X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/5c58ad2d1527936b4d30891497eef48bde0fe1f3..514702987c9252fcb0ab98882a6603b3bd0505ce:/ssh.c diff --git a/ssh.c b/ssh.c index dd8ffd57..115e902f 100644 --- a/ssh.c +++ b/ssh.c @@ -1,12 +1,12 @@ +#include #include #include #include #include -#include #include "putty.h" +#include "tree234.h" #include "ssh.h" -#include "scp.h" #ifndef FALSE #define FALSE 0 @@ -16,86 +16,264 @@ #endif #define logevent(s) { logevent(s); \ - if (!(flags & FLAG_CONNECTION) && (flags & FLAG_VERBOSE)) \ - fprintf(stderr, "%s\n", s); } - -#define SSH1_MSG_DISCONNECT 1 -#define SSH1_SMSG_PUBLIC_KEY 2 -#define SSH1_CMSG_SESSION_KEY 3 -#define SSH1_CMSG_USER 4 -#define SSH1_CMSG_AUTH_RSA 6 -#define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 -#define SSH1_CMSG_AUTH_RSA_RESPONSE 8 -#define SSH1_CMSG_AUTH_PASSWORD 9 -#define SSH1_CMSG_REQUEST_PTY 10 -#define SSH1_CMSG_WINDOW_SIZE 11 -#define SSH1_CMSG_EXEC_SHELL 12 -#define SSH1_CMSG_EXEC_CMD 13 -#define SSH1_SMSG_SUCCESS 14 -#define SSH1_SMSG_FAILURE 15 -#define SSH1_CMSG_STDIN_DATA 16 -#define SSH1_SMSG_STDOUT_DATA 17 -#define SSH1_SMSG_STDERR_DATA 18 -#define SSH1_CMSG_EOF 19 -#define SSH1_SMSG_EXIT_STATUS 20 -#define SSH1_CMSG_EXIT_CONFIRMATION 33 -#define SSH1_MSG_IGNORE 32 -#define SSH1_MSG_DEBUG 36 -#define SSH1_CMSG_AUTH_TIS 39 -#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 -#define SSH1_CMSG_AUTH_TIS_RESPONSE 41 -#define SSH1_CMSG_AUTH_CCARD 70 -#define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 -#define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 - -#define SSH1_AUTH_TIS 5 -#define SSH1_AUTH_CCARD 16 - -#define SSH_AGENTC_REQUEST_RSA_IDENTITIES 1 -#define SSH_AGENT_RSA_IDENTITIES_ANSWER 2 -#define SSH_AGENTC_RSA_CHALLENGE 3 -#define SSH_AGENT_RSA_RESPONSE 4 -#define SSH_AGENT_FAILURE 5 -#define SSH_AGENT_SUCCESS 6 -#define SSH_AGENTC_ADD_RSA_IDENTITY 7 -#define SSH_AGENTC_REMOVE_RSA_IDENTITY 8 - -#define SSH2_MSG_DISCONNECT 1 -#define SSH2_MSG_IGNORE 2 -#define SSH2_MSG_UNIMPLEMENTED 3 -#define SSH2_MSG_DEBUG 4 -#define SSH2_MSG_SERVICE_REQUEST 5 -#define SSH2_MSG_SERVICE_ACCEPT 6 -#define SSH2_MSG_KEXINIT 20 -#define SSH2_MSG_NEWKEYS 21 -#define SSH2_MSG_KEXDH_INIT 30 -#define SSH2_MSG_KEXDH_REPLY 31 -#define SSH2_MSG_USERAUTH_REQUEST 50 -#define SSH2_MSG_USERAUTH_FAILURE 51 -#define SSH2_MSG_USERAUTH_SUCCESS 52 -#define SSH2_MSG_USERAUTH_BANNER 53 -#define SSH2_MSG_USERAUTH_PK_OK 60 -#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 -#define SSH2_MSG_GLOBAL_REQUEST 80 -#define SSH2_MSG_REQUEST_SUCCESS 81 -#define SSH2_MSG_REQUEST_FAILURE 82 -#define SSH2_MSG_CHANNEL_OPEN 90 -#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 -#define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 -#define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 -#define SSH2_MSG_CHANNEL_DATA 94 -#define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 -#define SSH2_MSG_CHANNEL_EOF 96 -#define SSH2_MSG_CHANNEL_CLOSE 97 -#define SSH2_MSG_CHANNEL_REQUEST 98 -#define SSH2_MSG_CHANNEL_SUCCESS 99 -#define SSH2_MSG_CHANNEL_FAILURE 100 - -#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 -#define SSH2_OPEN_CONNECT_FAILED 2 -#define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 -#define SSH2_OPEN_RESOURCE_SHORTAGE 4 -#define SSH2_EXTENDED_DATA_STDERR 1 + if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \ + { fprintf(stderr, "%s\n", s); fflush(stderr); } } + +/* logevent, only printf-formatted. */ +void logeventf(char *fmt, ...) +{ + va_list ap; + char stuff[200]; + + va_start(ap, fmt); + vsprintf(stuff, fmt, ap); + va_end(ap); + logevent(stuff); +} + +#define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \ + (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \ + logeventf msg, connection_fatal msg ) + +#define SSH1_MSG_DISCONNECT 1 /* 0x1 */ +#define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */ +#define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */ +#define SSH1_CMSG_USER 4 /* 0x4 */ +#define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */ +#define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */ +#define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */ +#define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */ +#define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */ +#define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */ +#define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */ +#define SSH1_CMSG_EXEC_CMD 13 /* 0xd */ +#define SSH1_SMSG_SUCCESS 14 /* 0xe */ +#define SSH1_SMSG_FAILURE 15 /* 0xf */ +#define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */ +#define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */ +#define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */ +#define SSH1_CMSG_EOF 19 /* 0x13 */ +#define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */ +#define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */ +#define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */ +#define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */ +#define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */ +#define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */ +#define SSH1_SMSG_X11_OPEN 27 /* 0x1b */ +#define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */ +#define SSH1_MSG_PORT_OPEN 29 /* 0x1d */ +#define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */ +#define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */ +#define SSH1_MSG_IGNORE 32 /* 0x20 */ +#define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */ +#define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */ +#define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */ +#define SSH1_MSG_DEBUG 36 /* 0x24 */ +#define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */ +#define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */ +#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */ +#define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */ +#define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */ +#define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */ +#define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */ + +#define SSH1_AUTH_TIS 5 /* 0x5 */ +#define SSH1_AUTH_CCARD 16 /* 0x10 */ + +#define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */ +/* Mask for protoflags we will echo back to server if seen */ +#define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */ + +#define SSH2_MSG_DISCONNECT 1 /* 0x1 */ +#define SSH2_MSG_IGNORE 2 /* 0x2 */ +#define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */ +#define SSH2_MSG_DEBUG 4 /* 0x4 */ +#define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */ +#define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */ +#define SSH2_MSG_KEXINIT 20 /* 0x14 */ +#define SSH2_MSG_NEWKEYS 21 /* 0x15 */ +#define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */ +#define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */ +#define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */ +#define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */ +#define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */ +#define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */ +#define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */ +#define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */ +#define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */ +#define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */ +#define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */ +#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */ +#define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */ +#define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */ +#define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */ +#define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */ +#define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */ +#define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */ +#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */ +#define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */ +#define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */ +#define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */ +#define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */ +#define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */ +#define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */ +#define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */ +#define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */ +#define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */ + +/* + * Packet type contexts, so that ssh2_pkt_type can correctly decode + * the ambiguous type numbers back into the correct type strings. + */ +#define SSH2_PKTCTX_DHGROUP1 0x0001 +#define SSH2_PKTCTX_DHGEX 0x0002 +#define SSH2_PKTCTX_PUBLICKEY 0x0010 +#define SSH2_PKTCTX_PASSWORD 0x0020 +#define SSH2_PKTCTX_KBDINTER 0x0040 +#define SSH2_PKTCTX_AUTH_MASK 0x00F0 + +#define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */ +#define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */ +#define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */ +#define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */ +#define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */ +#define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */ +#define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */ +#define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */ +#define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */ +#define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */ +#define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */ +#define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */ +#define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */ +#define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */ +#define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */ + +static const char *const ssh2_disconnect_reasons[] = { + NULL, + "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT", + "SSH_DISCONNECT_PROTOCOL_ERROR", + "SSH_DISCONNECT_KEY_EXCHANGE_FAILED", + "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED", + "SSH_DISCONNECT_MAC_ERROR", + "SSH_DISCONNECT_COMPRESSION_ERROR", + "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE", + "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED", + "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE", + "SSH_DISCONNECT_CONNECTION_LOST", + "SSH_DISCONNECT_BY_APPLICATION", + "SSH_DISCONNECT_TOO_MANY_CONNECTIONS", + "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER", + "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE", + "SSH_DISCONNECT_ILLEGAL_USER_NAME", +}; + +#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */ +#define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */ +#define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */ +#define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */ + +#define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */ + +/* + * Various remote-bug flags. + */ +#define BUG_CHOKES_ON_SSH1_IGNORE 1 +#define BUG_SSH2_HMAC 2 +#define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4 +#define BUG_CHOKES_ON_RSA 8 +#define BUG_SSH2_RSA_PADDING 16 +#define BUG_SSH2_DERIVEKEY 32 +#define BUG_SSH2_DH_GEX 64 + +#define translate(x) if (type == x) return #x +#define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x +char *ssh1_pkt_type(int type) +{ + translate(SSH1_MSG_DISCONNECT); + translate(SSH1_SMSG_PUBLIC_KEY); + translate(SSH1_CMSG_SESSION_KEY); + translate(SSH1_CMSG_USER); + translate(SSH1_CMSG_AUTH_RSA); + translate(SSH1_SMSG_AUTH_RSA_CHALLENGE); + translate(SSH1_CMSG_AUTH_RSA_RESPONSE); + translate(SSH1_CMSG_AUTH_PASSWORD); + translate(SSH1_CMSG_REQUEST_PTY); + translate(SSH1_CMSG_WINDOW_SIZE); + translate(SSH1_CMSG_EXEC_SHELL); + translate(SSH1_CMSG_EXEC_CMD); + translate(SSH1_SMSG_SUCCESS); + translate(SSH1_SMSG_FAILURE); + translate(SSH1_CMSG_STDIN_DATA); + translate(SSH1_SMSG_STDOUT_DATA); + translate(SSH1_SMSG_STDERR_DATA); + translate(SSH1_CMSG_EOF); + translate(SSH1_SMSG_EXIT_STATUS); + translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION); + translate(SSH1_MSG_CHANNEL_OPEN_FAILURE); + translate(SSH1_MSG_CHANNEL_DATA); + translate(SSH1_MSG_CHANNEL_CLOSE); + translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION); + translate(SSH1_SMSG_X11_OPEN); + translate(SSH1_CMSG_PORT_FORWARD_REQUEST); + translate(SSH1_MSG_PORT_OPEN); + translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING); + translate(SSH1_SMSG_AGENT_OPEN); + translate(SSH1_MSG_IGNORE); + translate(SSH1_CMSG_EXIT_CONFIRMATION); + translate(SSH1_CMSG_X11_REQUEST_FORWARDING); + translate(SSH1_CMSG_AUTH_RHOSTS_RSA); + translate(SSH1_MSG_DEBUG); + translate(SSH1_CMSG_REQUEST_COMPRESSION); + translate(SSH1_CMSG_AUTH_TIS); + translate(SSH1_SMSG_AUTH_TIS_CHALLENGE); + translate(SSH1_CMSG_AUTH_TIS_RESPONSE); + translate(SSH1_CMSG_AUTH_CCARD); + translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE); + translate(SSH1_CMSG_AUTH_CCARD_RESPONSE); + return "unknown"; +} +char *ssh2_pkt_type(int pkt_ctx, int type) +{ + translate(SSH2_MSG_DISCONNECT); + translate(SSH2_MSG_IGNORE); + translate(SSH2_MSG_UNIMPLEMENTED); + translate(SSH2_MSG_DEBUG); + translate(SSH2_MSG_SERVICE_REQUEST); + translate(SSH2_MSG_SERVICE_ACCEPT); + translate(SSH2_MSG_KEXINIT); + translate(SSH2_MSG_NEWKEYS); + translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1); + translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1); + translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX); + translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX); + translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX); + translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX); + translate(SSH2_MSG_USERAUTH_REQUEST); + translate(SSH2_MSG_USERAUTH_FAILURE); + translate(SSH2_MSG_USERAUTH_SUCCESS); + translate(SSH2_MSG_USERAUTH_BANNER); + translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY); + translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD); + translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER); + translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER); + translate(SSH2_MSG_GLOBAL_REQUEST); + translate(SSH2_MSG_REQUEST_SUCCESS); + translate(SSH2_MSG_REQUEST_FAILURE); + translate(SSH2_MSG_CHANNEL_OPEN); + translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); + translate(SSH2_MSG_CHANNEL_OPEN_FAILURE); + translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST); + translate(SSH2_MSG_CHANNEL_DATA); + translate(SSH2_MSG_CHANNEL_EXTENDED_DATA); + translate(SSH2_MSG_CHANNEL_EOF); + translate(SSH2_MSG_CHANNEL_CLOSE); + translate(SSH2_MSG_CHANNEL_REQUEST); + translate(SSH2_MSG_CHANNEL_SUCCESS); + translate(SSH2_MSG_CHANNEL_FAILURE); + return "unknown"; +} +#undef translate +#undef translatec #define GET_32BIT(cp) \ (((unsigned long)(unsigned char)(cp)[0] << 24) | \ @@ -112,116 +290,215 @@ enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM }; /* Coroutine mechanics for the sillier bits of the code */ -#define crBegin1 static int crLine = 0; -#define crBegin2 switch(crLine) { case 0:; -#define crBegin crBegin1; crBegin2; -#define crFinish(z) } crLine = 0; return (z) -#define crFinishV } crLine = 0; return +#define crBegin(v) { int *crLine = &v; switch(v) { case 0:; +#define crState(t) \ + struct t *s; \ + if (!ssh->t) ssh->t = smalloc(sizeof(struct t)); \ + s = ssh->t; +#define crFinish(z) } *crLine = 0; return (z); } +#define crFinishV } *crLine = 0; return; } #define crReturn(z) \ do {\ - crLine=__LINE__; return (z); case __LINE__:;\ + *crLine =__LINE__; return (z); case __LINE__:;\ } while (0) #define crReturnV \ do {\ - crLine=__LINE__; return; case __LINE__:;\ + *crLine=__LINE__; return; case __LINE__:;\ } while (0) -#define crStop(z) do{ crLine = 0; return (z); }while(0) -#define crStopV do{ crLine = 0; return; }while(0) +#define crStop(z) do{ *crLine = 0; return (z); }while(0) +#define crStopV do{ *crLine = 0; return; }while(0) #define crWaitUntil(c) do { crReturn(0); } while (!(c)) #define crWaitUntilV(c) do { crReturnV; } while (!(c)) -extern struct ssh_cipher ssh_3des; -extern struct ssh_cipher ssh_3des_ssh2; -extern struct ssh_cipher ssh_des; -extern struct ssh_cipher ssh_blowfish; +typedef struct ssh_tag *Ssh; + +extern char *x11_init(Socket *, char *, void *); +extern void x11_close(Socket); +extern int x11_send(Socket, char *, int); +extern void x11_invent_auth(char *, int, char *, int); +extern void x11_unthrottle(Socket s); +extern void x11_override_throttle(Socket s, int enable); + +extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c); +extern char *pfd_addforward(char *desthost, int destport, int port); +extern void pfd_close(Socket s); +extern int pfd_send(Socket s, char *data, int len); +extern void pfd_confirm(Socket s); +extern void pfd_unthrottle(Socket s); +extern void pfd_override_throttle(Socket s, int enable); + +static void ssh2_pkt_init(Ssh, int pkt_type); +static void ssh2_pkt_addbool(Ssh, unsigned char value); +static void ssh2_pkt_adduint32(Ssh, unsigned long value); +static void ssh2_pkt_addstring_start(Ssh); +static void ssh2_pkt_addstring_str(Ssh, char *data); +static void ssh2_pkt_addstring_data(Ssh, char *data, int len); +static void ssh2_pkt_addstring(Ssh, char *data); +static char *ssh2_mpint_fmt(Bignum b, int *len); +static void ssh2_pkt_addmp(Ssh, Bignum b); +static int ssh2_pkt_construct(Ssh); +static void ssh2_pkt_send(Ssh); -/* for ssh 2; we miss out single-DES because it isn't supported */ -struct ssh_cipher *ciphers[] = { &ssh_3des_ssh2, &ssh_blowfish }; - -extern struct ssh_kex ssh_diffiehellman; -struct ssh_kex *kex_algs[] = { &ssh_diffiehellman }; +/* + * Buffer management constants. There are several of these for + * various different purposes: + * + * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up + * on a local data stream before we throttle the whole SSH + * connection (in SSH1 only). Throttling the whole connection is + * pretty drastic so we set this high in the hope it won't + * happen very often. + * + * - SSH_MAX_BACKLOG is the amount of backlog that must build up + * on the SSH connection itself before we defensively throttle + * _all_ local data streams. This is pretty drastic too (though + * thankfully unlikely in SSH2 since the window mechanism should + * ensure that the server never has any need to throttle its end + * of the connection), so we set this high as well. + * + * - OUR_V2_WINSIZE is the maximum window size we present on SSH2 + * channels. + */ -extern struct ssh_hostkey ssh_dss; -struct ssh_hostkey *hostkey_algs[] = { &ssh_dss }; +#define SSH1_BUFFER_LIMIT 32768 +#define SSH_MAX_BACKLOG 32768 +#define OUR_V2_WINSIZE 16384 -extern struct ssh_mac ssh_sha1; +const static struct ssh_kex *kex_algs[] = { + &ssh_diffiehellman_gex, + &ssh_diffiehellman +}; -SHA_State exhash; +const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss }; -static void nullmac_key(unsigned char *key) { } -static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { } -static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; } -struct ssh_mac ssh_mac_none = { +static void nullmac_key(unsigned char *key) +{ +} +static void nullmac_generate(unsigned char *blk, int len, + unsigned long seq) +{ +} +static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) +{ + return 1; +} +const static struct ssh_mac ssh_mac_none = { nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0 }; -struct ssh_mac *macs[] = { &ssh_sha1, &ssh_mac_none }; - -struct ssh_compress ssh_comp_none = { - "none" +const static struct ssh_mac *macs[] = { + &ssh_sha1, &ssh_md5, &ssh_mac_none +}; +const static struct ssh_mac *buggymacs[] = { + &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none }; -struct ssh_compress *compressions[] = { &ssh_comp_none }; - -static SOCKET s = INVALID_SOCKET; - -static unsigned char session_key[32]; -static struct ssh_cipher *cipher = NULL; -static struct ssh_cipher *cscipher = NULL; -static struct ssh_cipher *sccipher = NULL; -static struct ssh_mac *csmac = NULL; -static struct ssh_mac *scmac = NULL; -static struct ssh_compress *cscomp = NULL; -static struct ssh_compress *sccomp = NULL; -static struct ssh_kex *kex = NULL; -static struct ssh_hostkey *hostkey = NULL; -int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL; - -static char *savedhost; -static int ssh_send_ok; - -static enum { - SSH_STATE_BEFORE_SIZE, - SSH_STATE_INTERMED, - SSH_STATE_SESSION, - SSH_STATE_CLOSED -} ssh_state = SSH_STATE_BEFORE_SIZE; - -static int size_needed = FALSE; - -static void s_write (char *buf, int len) { - while (len > 0) { - int i = send (s, buf, len, 0); - noise_ultralight(i); - if (i <= 0) - fatalbox("Lost connection while sending"); - if (i > 0) - len -= i, buf += i; - } -} - -static int s_read (char *buf, int len) { - int ret = 0; - while (len > 0) { - int i = recv (s, buf, len, 0); - noise_ultralight(i); - if (i > 0) - len -= i, buf += i, ret += i; - else - return i; - } - return ret; -} -static void c_write (char *buf, int len) { - if (!(flags & FLAG_CONNECTION)) { - int i; - for (i = 0; i < len; i++) - if (buf[i] != '\r') - fputc(buf[i], stderr); - return; - } - while (len--) - c_write1(*buf++); +static void ssh_comp_none_init(void) +{ +} +static int ssh_comp_none_block(unsigned char *block, int len, + unsigned char **outblock, int *outlen) +{ + return 0; } +static int ssh_comp_none_disable(void) +{ + return 0; +} +const static struct ssh_compress ssh_comp_none = { + "none", + ssh_comp_none_init, ssh_comp_none_block, + ssh_comp_none_init, ssh_comp_none_block, + ssh_comp_none_disable +}; +extern const struct ssh_compress ssh_zlib; +const static struct ssh_compress *compressions[] = { + &ssh_zlib, &ssh_comp_none +}; + +enum { /* channel types */ + CHAN_MAINSESSION, + CHAN_X11, + CHAN_AGENT, + CHAN_SOCKDATA, + CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */ +}; + +/* + * 2-3-4 tree storing channels. + */ +struct ssh_channel { + Ssh ssh; /* pointer back to main context */ + unsigned remoteid, localid; + int type; + /* + * In SSH1, this value contains four bits: + * + * 1 We have sent SSH1_MSG_CHANNEL_CLOSE. + * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION. + * 4 We have received SSH1_MSG_CHANNEL_CLOSE. + * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION. + * + * A channel is completely finished with when all four bits are set. + */ + int closes; + union { + struct ssh1_data_channel { + int throttling; + } v1; + struct ssh2_data_channel { + bufchain outbuffer; + unsigned remwindow, remmaxpkt; + unsigned locwindow; + } v2; + } v; + union { + struct ssh_agent_channel { + unsigned char *message; + unsigned char msglen[4]; + int lensofar, totallen; + } a; + struct ssh_x11_channel { + Socket s; + } x11; + struct ssh_pfd_channel { + Socket s; + } pfd; + } u; +}; + +/* + * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH + * 2 use this structure in different ways, reflecting SSH 2's + * altogether saner approach to port forwarding. + * + * In SSH 1, you arrange a remote forwarding by sending the server + * the remote port number, and the local destination host:port. + * When a connection comes in, the server sends you back that + * host:port pair, and you connect to it. This is a ready-made + * security hole if you're not on the ball: a malicious server + * could send you back _any_ host:port pair, so if you trustingly + * connect to the address it gives you then you've just opened the + * entire inside of your corporate network just by connecting + * through it to a dodgy SSH server. Hence, we must store a list of + * host:port pairs we _are_ trying to forward to, and reject a + * connection request from the server if it's not in the list. + * + * In SSH 2, each side of the connection minds its own business and + * doesn't send unnecessary information to the other. You arrange a + * remote forwarding by sending the server just the remote port + * number. When a connection comes in, the server tells you which + * of its ports was connected to; and _you_ have to remember what + * local host:port pair went with that port number. + * + * Hence: in SSH 1 this structure stores host:port pairs we intend + * to allow connections to, and is indexed by those host:port + * pairs. In SSH 2 it stores a mapping from source port to + * destination host:port pair, and is indexed by source port. + */ +struct ssh_rportfwd { + unsigned sport, dport; + char dhost[256]; +}; struct Packet { long length; @@ -232,16 +509,243 @@ struct Packet { long maxlen; }; -static struct Packet pktin = { 0, 0, NULL, NULL, 0 }; -static struct Packet pktout = { 0, 0, NULL, NULL, 0 }; +static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt); +static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt); +static void ssh_size(void *handle, int width, int height); +static void ssh_special(void *handle, Telnet_Special); +static int ssh2_try_send(struct ssh_channel *c); +static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len); +static void ssh_throttle_all(Ssh ssh, int enable, int bufsize); +static void ssh2_set_window(struct ssh_channel *c, unsigned newwin); +static int ssh_sendbuffer(void *handle); + +struct rdpkt1_state_tag { + long len, pad, biglen, to_read; + unsigned long realcrc, gotcrc; + unsigned char *p; + int i; + int chunk; +}; + +struct rdpkt2_state_tag { + long len, pad, payload, packetlen, maclen; + int i; + int cipherblk; + unsigned long incoming_sequence; +}; + +struct ssh_tag { + const struct plug_function_table *fn; + /* the above field _must_ be first in the structure */ + + SHA_State exhash, exhashbase; + + Socket s; + + unsigned char session_key[32]; + int v1_compressing; + int v1_remote_protoflags; + int v1_local_protoflags; + int agentfwd_enabled; + int X11_fwd_enabled; + int remote_bugs; + const struct ssh_cipher *cipher; + const struct ssh2_cipher *cscipher, *sccipher; + const struct ssh_mac *csmac, *scmac; + const struct ssh_compress *cscomp, *sccomp; + const struct ssh_kex *kex; + const struct ssh_signkey *hostkey; + unsigned char v2_session_id[20]; + + char *savedhost; + int savedport; + int send_ok; + int echoing, editing; + + void *frontend; + + int term_width, term_height; + + tree234 *channels; /* indexed by local id */ + struct ssh_channel *mainchan; /* primary session channel */ + int exitcode; + + tree234 *rportfwds; + + enum { + SSH_STATE_PREPACKET, + SSH_STATE_BEFORE_SIZE, + SSH_STATE_INTERMED, + SSH_STATE_SESSION, + SSH_STATE_CLOSED + } state; + + int size_needed, eof_needed; + + struct Packet pktin; + struct Packet pktout; + unsigned char *deferred_send_data; + int deferred_len, deferred_size; + + /* + * Gross hack: pscp will try to start SFTP but fall back to + * scp1 if that fails. This variable is the means by which + * scp.c can reach into the SSH code and find out which one it + * got. + */ + int fallback_cmd; + + /* + * Used for username and password input. + */ + char *userpass_input_buffer; + int userpass_input_buflen; + int userpass_input_bufpos; + int userpass_input_echo; + + char *portfwd_strptr; + int pkt_ctx; + + int version; + int v1_throttle_count; + int overall_bufsize; + int throttled_all; + int v1_stdout_throttling; + int v2_outgoing_sequence; + + int ssh1_rdpkt_crstate; + int ssh2_rdpkt_crstate; + int do_ssh_init_crstate; + int ssh_gotdata_crstate; + int ssh1_protocol_crstate; + int do_ssh1_login_crstate; + int do_ssh2_transport_crstate; + int do_ssh2_authconn_crstate; + + void *do_ssh_init_state; + void *do_ssh1_login_state; + void *do_ssh2_transport_state; + void *do_ssh2_authconn_state; + + struct rdpkt1_state_tag rdpkt1_state; + struct rdpkt2_state_tag rdpkt2_state; + + void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt); + int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen); +}; + +static int ssh_channelcmp(void *av, void *bv) +{ + struct ssh_channel *a = (struct ssh_channel *) av; + struct ssh_channel *b = (struct ssh_channel *) bv; + if (a->localid < b->localid) + return -1; + if (a->localid > b->localid) + return +1; + return 0; +} +static int ssh_channelfind(void *av, void *bv) +{ + unsigned *a = (unsigned *) av; + struct ssh_channel *b = (struct ssh_channel *) bv; + if (*a < b->localid) + return -1; + if (*a > b->localid) + return +1; + return 0; +} + +static int ssh_rportcmp_ssh1(void *av, void *bv) +{ + struct ssh_rportfwd *a = (struct ssh_rportfwd *) av; + struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv; + int i; + if ( (i = strcmp(a->dhost, b->dhost)) != 0) + return i < 0 ? -1 : +1; + if (a->dport > b->dport) + return +1; + if (a->dport < b->dport) + return -1; + return 0; +} + +static int ssh_rportcmp_ssh2(void *av, void *bv) +{ + struct ssh_rportfwd *a = (struct ssh_rportfwd *) av; + struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv; + + if (a->sport > b->sport) + return +1; + if (a->sport < b->sport) + return -1; + return 0; +} + +static int alloc_channel_id(Ssh ssh) +{ + const unsigned CHANNEL_NUMBER_OFFSET = 256; + unsigned low, high, mid; + int tsize; + struct ssh_channel *c; + + /* + * First-fit allocation of channel numbers: always pick the + * lowest unused one. To do this, binary-search using the + * counted B-tree to find the largest channel ID which is in a + * contiguous sequence from the beginning. (Precisely + * everything in that sequence must have ID equal to its tree + * index plus CHANNEL_NUMBER_OFFSET.) + */ + tsize = count234(ssh->channels); + + low = -1; + high = tsize; + while (high - low > 1) { + mid = (high + low) / 2; + c = index234(ssh->channels, mid); + if (c->localid == mid + CHANNEL_NUMBER_OFFSET) + low = mid; /* this one is fine */ + else + high = mid; /* this one is past it */ + } + /* + * Now low points to either -1, or the tree index of the + * largest ID in the initial sequence. + */ + { + unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET; + assert(NULL == find234(ssh->channels, &i, ssh_channelfind)); + } + return low + 1 + CHANNEL_NUMBER_OFFSET; +} -static int ssh_version; -static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt); -static void ssh1_protocol(unsigned char *in, int inlen, int ispkt); -static void ssh2_protocol(unsigned char *in, int inlen, int ispkt); -static void ssh_size(void); +static void c_write(Ssh ssh, char *buf, int len) +{ + if ((flags & FLAG_STDERR)) { + int i; + for (i = 0; i < len; i++) + if (buf[i] != '\r') + fputc(buf[i], stderr); + return; + } + from_backend(ssh->frontend, 1, buf, len); +} + +static void c_write_untrusted(Ssh ssh, char *buf, int len) +{ + int i; + for (i = 0; i < len; i++) { + if (buf[i] == '\n') + c_write(ssh, "\r\n", 2); + else if ((buf[i] & 0x60) || (buf[i] == '\r')) + c_write(ssh, buf + i, 1); + } +} -static int (*s_rdpkt)(unsigned char **data, int *datalen); +static void c_write_str(Ssh ssh, char *buf) +{ + c_write(ssh, buf, strlen(buf)); +} /* * Collect incoming data in the incoming packet buffer. @@ -251,1233 +755,2130 @@ static int (*s_rdpkt)(unsigned char **data, int *datalen); * Return the additional nr of bytes needed, or 0 when * a complete packet is available. */ -static int ssh1_rdpkt(unsigned char **data, int *datalen) +static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen) { - static long len, pad, biglen, to_read; - static unsigned long realcrc, gotcrc; - static unsigned char *p; - static int i; + struct rdpkt1_state_tag *st = &ssh->rdpkt1_state; - crBegin; + crBegin(ssh->ssh1_rdpkt_crstate); -next_packet: + next_packet: - pktin.type = 0; - pktin.length = 0; + ssh->pktin.type = 0; + ssh->pktin.length = 0; - for (i = len = 0; i < 4; i++) { + for (st->i = st->len = 0; st->i < 4; st->i++) { while ((*datalen) == 0) - crReturn(4-i); - len = (len << 8) + **data; + crReturn(4 - st->i); + st->len = (st->len << 8) + **data; (*data)++, (*datalen)--; } -#ifdef FWHACK - if (len == 0x52656d6f) { /* "Remo"te server has closed ... */ - len = 0x300; /* big enough to carry to end */ + st->pad = 8 - (st->len % 8); + st->biglen = st->len + st->pad; + ssh->pktin.length = st->len - 5; + + if (ssh->pktin.maxlen < st->biglen) { + ssh->pktin.maxlen = st->biglen; + ssh->pktin.data = srealloc(ssh->pktin.data, st->biglen + APIEXTRA); } -#endif - pad = 8 - (len % 8); - biglen = len + pad; - pktin.length = len - 5; + st->to_read = st->biglen; + st->p = ssh->pktin.data; + while (st->to_read > 0) { + st->chunk = st->to_read; + while ((*datalen) == 0) + crReturn(st->to_read); + if (st->chunk > (*datalen)) + st->chunk = (*datalen); + memcpy(st->p, *data, st->chunk); + *data += st->chunk; + *datalen -= st->chunk; + st->p += st->chunk; + st->to_read -= st->chunk; + } - if (pktin.maxlen < biglen) { - pktin.maxlen = biglen; - pktin.data = (pktin.data == NULL ? malloc(biglen+APIEXTRA) : - realloc(pktin.data, biglen+APIEXTRA)); - if (!pktin.data) - fatalbox("Out of memory"); + if (ssh->cipher && detect_attack(ssh->pktin.data, st->biglen, NULL)) { + bombout(("Network attack (CRC compensation) detected!")); + crReturn(0); } - to_read = biglen; - p = pktin.data; - while (to_read > 0) { - static int chunk; - chunk = to_read; - while ((*datalen) == 0) - crReturn(to_read); - if (chunk > (*datalen)) - chunk = (*datalen); - memcpy(p, *data, chunk); - *data += chunk; - *datalen -= chunk; - p += chunk; - to_read -= chunk; + if (ssh->cipher) + ssh->cipher->decrypt(ssh->pktin.data, st->biglen); + + st->realcrc = crc32(ssh->pktin.data, st->biglen - 4); + st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4); + if (st->gotcrc != st->realcrc) { + bombout(("Incorrect CRC received on packet")); + crReturn(0); } - if (cipher) - cipher->decrypt(pktin.data, biglen); + ssh->pktin.body = ssh->pktin.data + st->pad + 1; + + if (ssh->v1_compressing) { + unsigned char *decompblk; + int decomplen; + zlib_decompress_block(ssh->pktin.body - 1, ssh->pktin.length + 1, + &decompblk, &decomplen); - pktin.type = pktin.data[pad]; - pktin.body = pktin.data + pad + 1; + if (ssh->pktin.maxlen < st->pad + decomplen) { + ssh->pktin.maxlen = st->pad + decomplen; + ssh->pktin.data = srealloc(ssh->pktin.data, + ssh->pktin.maxlen + APIEXTRA); + ssh->pktin.body = ssh->pktin.data + st->pad + 1; + } - realcrc = crc32(pktin.data, biglen-4); - gotcrc = GET_32BIT(pktin.data+biglen-4); - if (gotcrc != realcrc) { - fatalbox("Incorrect CRC received on packet"); + memcpy(ssh->pktin.body - 1, decompblk, decomplen); + sfree(decompblk); + ssh->pktin.length = decomplen - 1; } - if (pktin.type == SSH1_SMSG_STDOUT_DATA || - pktin.type == SSH1_SMSG_STDERR_DATA || - pktin.type == SSH1_MSG_DEBUG || - pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE || - pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) { - long strlen = GET_32BIT(pktin.body); - if (strlen + 4 != pktin.length) - fatalbox("Received data packet with bogus string length"); + ssh->pktin.type = ssh->pktin.body[-1]; + + log_packet(PKT_INCOMING, ssh->pktin.type, ssh1_pkt_type(ssh->pktin.type), + ssh->pktin.body, ssh->pktin.length); + + if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA || + ssh->pktin.type == SSH1_SMSG_STDERR_DATA || + ssh->pktin.type == SSH1_MSG_DEBUG || + ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE || + ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) { + long stringlen = GET_32BIT(ssh->pktin.body); + if (stringlen + 4 != ssh->pktin.length) { + bombout(("Received data packet with bogus string length")); + crReturn(0); + } } - if (pktin.type == SSH1_MSG_DEBUG) { + if (ssh->pktin.type == SSH1_MSG_DEBUG) { /* log debug message */ - char buf[80]; - int strlen = GET_32BIT(pktin.body); - strcpy(buf, "Remote: "); - if (strlen > 70) strlen = 70; - memcpy(buf+8, pktin.body+4, strlen); - buf[8+strlen] = '\0'; + char buf[512]; + int stringlen = GET_32BIT(ssh->pktin.body); + strcpy(buf, "Remote debug message: "); + if (stringlen > 480) + stringlen = 480; + memcpy(buf + 8, ssh->pktin.body + 4, stringlen); + buf[8 + stringlen] = '\0'; logevent(buf); goto next_packet; - } else if (pktin.type == SSH1_MSG_IGNORE) { + } else if (ssh->pktin.type == SSH1_MSG_IGNORE) { /* do nothing */ goto next_packet; } + if (ssh->pktin.type == SSH1_MSG_DISCONNECT) { + /* log reason code in disconnect message */ + char buf[256]; + unsigned msglen = GET_32BIT(ssh->pktin.body); + unsigned nowlen; + strcpy(buf, "Remote sent disconnect: "); + nowlen = strlen(buf); + if (msglen > sizeof(buf) - nowlen - 1) + msglen = sizeof(buf) - nowlen - 1; + memcpy(buf + nowlen, ssh->pktin.body + 4, msglen); + buf[nowlen + msglen] = '\0'; + /* logevent(buf); (this is now done within the bombout macro) */ + bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen)); + crReturn(0); + } + crFinish(0); } -static int ssh2_rdpkt(unsigned char **data, int *datalen) +static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen) { - static long len, pad, payload, packetlen, maclen; - static int i; - static int cipherblk; - static unsigned long incoming_sequence = 0; + struct rdpkt2_state_tag *st = &ssh->rdpkt2_state; - crBegin; + crBegin(ssh->ssh2_rdpkt_crstate); -next_packet: - - pktin.type = 0; - pktin.length = 0; - - if (cipher) - cipherblk = cipher->blksize; + next_packet: + ssh->pktin.type = 0; + ssh->pktin.length = 0; + if (ssh->sccipher) + st->cipherblk = ssh->sccipher->blksize; else - cipherblk = 8; - if (cipherblk < 8) - cipherblk = 8; - - if (pktin.maxlen < cipherblk) { - pktin.maxlen = cipherblk; - pktin.data = (pktin.data == NULL ? malloc(cipherblk+APIEXTRA) : - realloc(pktin.data, cipherblk+APIEXTRA)); - if (!pktin.data) - fatalbox("Out of memory"); + st->cipherblk = 8; + if (st->cipherblk < 8) + st->cipherblk = 8; + + if (ssh->pktin.maxlen < st->cipherblk) { + ssh->pktin.maxlen = st->cipherblk; + ssh->pktin.data = srealloc(ssh->pktin.data, st->cipherblk + APIEXTRA); } /* * Acquire and decrypt the first block of the packet. This will * contain the length and padding details. */ - for (i = len = 0; i < cipherblk; i++) { + for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) { while ((*datalen) == 0) - crReturn(cipherblk-i); - pktin.data[i] = *(*data)++; - (*datalen)--; + crReturn(st->cipherblk - st->i); + ssh->pktin.data[st->i] = *(*data)++; + (*datalen)--; } -#ifdef FWHACK - if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */ - /* FIXME */ - } -#endif - if (sccipher) - sccipher->decrypt(pktin.data, cipherblk); + + if (ssh->sccipher) + ssh->sccipher->decrypt(ssh->pktin.data, st->cipherblk); /* * Now get the length and padding figures. */ - len = GET_32BIT(pktin.data); - pad = pktin.data[4]; + st->len = GET_32BIT(ssh->pktin.data); + st->pad = ssh->pktin.data[4]; + + /* + * _Completely_ silly lengths should be stomped on before they + * do us any more damage. + */ + if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) { + bombout(("Incoming packet was garbled on decryption")); + crReturn(0); + } /* * This enables us to deduce the payload length. */ - payload = len - pad - 1; + st->payload = st->len - st->pad - 1; - pktin.length = payload + 5; + ssh->pktin.length = st->payload + 5; /* * So now we can work out the total packet length. */ - packetlen = len + 4; - maclen = scmac ? scmac->len : 0; + st->packetlen = st->len + 4; + st->maclen = ssh->scmac ? ssh->scmac->len : 0; /* * Adjust memory allocation if packet is too big. */ - if (pktin.maxlen < packetlen) { - pktin.maxlen = packetlen; - pktin.data = (pktin.data == NULL ? malloc(packetlen+APIEXTRA) : - realloc(pktin.data, packetlen+APIEXTRA)); - if (!pktin.data) - fatalbox("Out of memory"); + if (ssh->pktin.maxlen < st->packetlen + st->maclen) { + ssh->pktin.maxlen = st->packetlen + st->maclen; + ssh->pktin.data = srealloc(ssh->pktin.data, + ssh->pktin.maxlen + APIEXTRA); } /* * Read and decrypt the remainder of the packet. */ - for (i = cipherblk; i < packetlen + maclen; i++) { + for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen; + st->i++) { while ((*datalen) == 0) - crReturn(packetlen + maclen - i); - pktin.data[i] = *(*data)++; - (*datalen)--; + crReturn(st->packetlen + st->maclen - st->i); + ssh->pktin.data[st->i] = *(*data)++; + (*datalen)--; } /* Decrypt everything _except_ the MAC. */ - if (sccipher) - sccipher->decrypt(pktin.data + cipherblk, packetlen - cipherblk); - -#if 0 - debug(("Got packet len=%d pad=%d\r\n", len, pad)); - for (i = 0; i < packetlen; i++) - debug((" %02x", (unsigned char)pktin.data[i])); - debug(("\r\n")); -#endif + if (ssh->sccipher) + ssh->sccipher->decrypt(ssh->pktin.data + st->cipherblk, + st->packetlen - st->cipherblk); /* * Check the MAC. */ - if (scmac && !scmac->verify(pktin.data, len+4, incoming_sequence)) - fatalbox("Incorrect MAC received on packet"); - incoming_sequence++; /* whether or not we MACed */ + if (ssh->scmac + && !ssh->scmac->verify(ssh->pktin.data, st->len + 4, + st->incoming_sequence)) { + bombout(("Incorrect MAC received on packet")); + crReturn(0); + } + st->incoming_sequence++; /* whether or not we MACed */ - pktin.savedpos = 6; - pktin.type = pktin.data[5]; + /* + * Decompress packet payload. + */ + { + unsigned char *newpayload; + int newlen; + if (ssh->sccomp && + ssh->sccomp->decompress(ssh->pktin.data + 5, ssh->pktin.length - 5, + &newpayload, &newlen)) { + if (ssh->pktin.maxlen < newlen + 5) { + ssh->pktin.maxlen = newlen + 5; + ssh->pktin.data = srealloc(ssh->pktin.data, + ssh->pktin.maxlen + APIEXTRA); + } + ssh->pktin.length = 5 + newlen; + memcpy(ssh->pktin.data + 5, newpayload, newlen); + sfree(newpayload); + } + } - if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG) - goto next_packet; /* FIXME: print DEBUG message */ + ssh->pktin.savedpos = 6; + ssh->pktin.type = ssh->pktin.data[5]; - crFinish(0); -} + log_packet(PKT_INCOMING, ssh->pktin.type, + ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type), + ssh->pktin.data+6, ssh->pktin.length-6); -static void ssh_gotdata(unsigned char *data, int datalen) -{ - while (datalen > 0) { - if ( s_rdpkt(&data, &datalen) == 0 ) { - ssh_protocol(NULL, 0, 1); - if (ssh_state == SSH_STATE_CLOSED) { - return; + switch (ssh->pktin.type) { + /* + * These packets we must handle instantly. + */ + case SSH2_MSG_DISCONNECT: + { + /* log reason code in disconnect message */ + char buf[256]; + int reason = GET_32BIT(ssh->pktin.data + 6); + unsigned msglen = GET_32BIT(ssh->pktin.data + 10); + unsigned nowlen; + if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) { + sprintf(buf, "Received disconnect message (%s)", + ssh2_disconnect_reasons[reason]); + } else { + sprintf(buf, "Received disconnect message (unknown type %d)", + reason); } + logevent(buf); + strcpy(buf, "Disconnection message text: "); + nowlen = strlen(buf); + if (msglen > sizeof(buf) - nowlen - 1) + msglen = sizeof(buf) - nowlen - 1; + memcpy(buf + nowlen, ssh->pktin.data + 14, msglen); + buf[nowlen + msglen] = '\0'; + logevent(buf); + bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"", + reason, + (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ? + ssh2_disconnect_reasons[reason] : "unknown", + buf+nowlen)); + crReturn(0); } + break; + case SSH2_MSG_IGNORE: + goto next_packet; + case SSH2_MSG_DEBUG: + { + /* log the debug message */ + char buf[512]; + /* int display = ssh->pktin.body[6]; */ + int stringlen = GET_32BIT(ssh->pktin.data+7); + int prefix; + strcpy(buf, "Remote debug message: "); + prefix = strlen(buf); + if (stringlen > (int)(sizeof(buf)-prefix-1)) + stringlen = sizeof(buf)-prefix-1; + memcpy(buf + prefix, ssh->pktin.data + 11, stringlen); + buf[prefix + stringlen] = '\0'; + logevent(buf); + } + goto next_packet; /* FIXME: print the debug message */ + + /* + * These packets we need do nothing about here. + */ + case SSH2_MSG_UNIMPLEMENTED: + case SSH2_MSG_SERVICE_REQUEST: + case SSH2_MSG_SERVICE_ACCEPT: + case SSH2_MSG_KEXINIT: + case SSH2_MSG_NEWKEYS: + case SSH2_MSG_KEXDH_INIT: + case SSH2_MSG_KEXDH_REPLY: + /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */ + /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */ + case SSH2_MSG_KEX_DH_GEX_INIT: + case SSH2_MSG_KEX_DH_GEX_REPLY: + case SSH2_MSG_USERAUTH_REQUEST: + case SSH2_MSG_USERAUTH_FAILURE: + case SSH2_MSG_USERAUTH_SUCCESS: + case SSH2_MSG_USERAUTH_BANNER: + case SSH2_MSG_USERAUTH_PK_OK: + /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */ + /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */ + case SSH2_MSG_USERAUTH_INFO_RESPONSE: + case SSH2_MSG_GLOBAL_REQUEST: + case SSH2_MSG_REQUEST_SUCCESS: + case SSH2_MSG_REQUEST_FAILURE: + case SSH2_MSG_CHANNEL_OPEN: + case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: + case SSH2_MSG_CHANNEL_OPEN_FAILURE: + case SSH2_MSG_CHANNEL_WINDOW_ADJUST: + case SSH2_MSG_CHANNEL_DATA: + case SSH2_MSG_CHANNEL_EXTENDED_DATA: + case SSH2_MSG_CHANNEL_EOF: + case SSH2_MSG_CHANNEL_CLOSE: + case SSH2_MSG_CHANNEL_REQUEST: + case SSH2_MSG_CHANNEL_SUCCESS: + case SSH2_MSG_CHANNEL_FAILURE: + break; + + /* + * For anything else we send SSH2_MSG_UNIMPLEMENTED. + */ + default: + ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED); + ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1); + ssh2_pkt_send(ssh); + break; } -} + crFinish(0); +} -static void s_wrpkt_start(int type, int len) { +static void ssh1_pktout_size(Ssh ssh, int len) +{ int pad, biglen; len += 5; /* type and CRC */ - pad = 8 - (len%8); + pad = 8 - (len % 8); biglen = len + pad; - pktout.length = len-5; - if (pktout.maxlen < biglen) { - pktout.maxlen = biglen; + ssh->pktout.length = len - 5; + if (ssh->pktout.maxlen < biglen) { + ssh->pktout.maxlen = biglen; #ifdef MSCRYPTOAPI /* Allocate enough buffer space for extra block * for MS CryptEncrypt() */ - pktout.data = (pktout.data == NULL ? malloc(biglen+12) : - realloc(pktout.data, biglen+12)); + ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 12); #else - pktout.data = (pktout.data == NULL ? malloc(biglen+4) : - realloc(pktout.data, biglen+4)); + ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 4); #endif - if (!pktout.data) - fatalbox("Out of memory"); } + ssh->pktout.body = ssh->pktout.data + 4 + pad + 1; +} - pktout.type = type; - pktout.body = pktout.data+4+pad+1; +static void s_wrpkt_start(Ssh ssh, int type, int len) +{ + ssh1_pktout_size(ssh, len); + ssh->pktout.type = type; } -static void s_wrpkt(void) { +static int s_wrpkt_prepare(Ssh ssh) +{ int pad, len, biglen, i; unsigned long crc; - len = pktout.length + 5; /* type and CRC */ - pad = 8 - (len%8); + ssh->pktout.body[-1] = ssh->pktout.type; + + log_packet(PKT_OUTGOING, ssh->pktout.type, ssh1_pkt_type(ssh->pktout.type), + ssh->pktout.body, ssh->pktout.length); + + if (ssh->v1_compressing) { + unsigned char *compblk; + int complen; + zlib_compress_block(ssh->pktout.body - 1, ssh->pktout.length + 1, + &compblk, &complen); + ssh1_pktout_size(ssh, complen - 1); + memcpy(ssh->pktout.body - 1, compblk, complen); + sfree(compblk); + } + + len = ssh->pktout.length + 5; /* type and CRC */ + pad = 8 - (len % 8); biglen = len + pad; - pktout.body[-1] = pktout.type; - for (i=0; ipktout.data[i + 4] = random_byte(); + crc = crc32(ssh->pktout.data + 4, biglen - 4); + PUT_32BIT(ssh->pktout.data + biglen, crc); + PUT_32BIT(ssh->pktout.data, len); + + if (ssh->cipher) + ssh->cipher->encrypt(ssh->pktout.data + 4, biglen); + + return biglen + 4; +} - if (cipher) - cipher->encrypt(pktout.data+4, biglen); +static void s_wrpkt(Ssh ssh) +{ + int len, backlog; + len = s_wrpkt_prepare(ssh); + backlog = sk_write(ssh->s, ssh->pktout.data, len); + if (backlog > SSH_MAX_BACKLOG) + ssh_throttle_all(ssh, 1, backlog); +} - s_write(pktout.data, biglen+4); +static void s_wrpkt_defer(Ssh ssh) +{ + int len; + len = s_wrpkt_prepare(ssh); + if (ssh->deferred_len + len > ssh->deferred_size) { + ssh->deferred_size = ssh->deferred_len + len + 128; + ssh->deferred_send_data = srealloc(ssh->deferred_send_data, + ssh->deferred_size); + } + memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len); + ssh->deferred_len += len; } /* - * Construct a packet with the specified contents and - * send it to the server. + * Construct a packet with the specified contents. */ -static void send_packet(int pkttype, ...) +static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2) { - va_list args; unsigned char *p, *argp, argchar; unsigned long argint; int pktlen, argtype, arglen; Bignum bn; pktlen = 0; - va_start(args, pkttype); - while ((argtype = va_arg(args, int)) != PKT_END) { + while ((argtype = va_arg(ap1, int)) != PKT_END) { switch (argtype) { case PKT_INT: - (void) va_arg(args, int); + (void) va_arg(ap1, int); pktlen += 4; break; case PKT_CHAR: - (void) va_arg(args, char); + (void) va_arg(ap1, char); pktlen++; break; case PKT_DATA: - (void) va_arg(args, unsigned char *); - arglen = va_arg(args, int); + (void) va_arg(ap1, unsigned char *); + arglen = va_arg(ap1, int); pktlen += arglen; break; case PKT_STR: - argp = va_arg(args, unsigned char *); + argp = va_arg(ap1, unsigned char *); arglen = strlen(argp); pktlen += 4 + arglen; break; case PKT_BIGNUM: - bn = va_arg(args, Bignum); - pktlen += ssh1_bignum_length(bn); + bn = va_arg(ap1, Bignum); + pktlen += ssh1_bignum_length(bn); break; default: assert(0); } } - va_end(args); - s_wrpkt_start(pkttype, pktlen); - p = pktout.body; + s_wrpkt_start(ssh, pkttype, pktlen); + p = ssh->pktout.body; - va_start(args, pkttype); - while ((argtype = va_arg(args, int)) != PKT_END) { + while ((argtype = va_arg(ap2, int)) != PKT_END) { switch (argtype) { case PKT_INT: - argint = va_arg(args, int); + argint = va_arg(ap2, int); PUT_32BIT(p, argint); p += 4; break; case PKT_CHAR: - argchar = va_arg(args, unsigned char); + argchar = va_arg(ap2, unsigned char); *p = argchar; p++; break; case PKT_DATA: - argp = va_arg(args, unsigned char *); - arglen = va_arg(args, int); + argp = va_arg(ap2, unsigned char *); + arglen = va_arg(ap2, int); memcpy(p, argp, arglen); p += arglen; break; case PKT_STR: - argp = va_arg(args, unsigned char *); + argp = va_arg(ap2, unsigned char *); arglen = strlen(argp); PUT_32BIT(p, arglen); memcpy(p + 4, argp, arglen); p += 4 + arglen; break; case PKT_BIGNUM: - bn = va_arg(args, Bignum); - p += ssh1_write_bignum(p, bn); + bn = va_arg(ap2, Bignum); + p += ssh1_write_bignum(p, bn); break; } } - va_end(args); - - s_wrpkt(); } +static void send_packet(Ssh ssh, int pkttype, ...) +{ + va_list ap1, ap2; + va_start(ap1, pkttype); + va_start(ap2, pkttype); + construct_packet(ssh, pkttype, ap1, ap2); + s_wrpkt(ssh); +} -/* - * Connect to specified host and port. - * Returns an error message, or NULL on success. - * Also places the canonical host name into `realhost'. - */ -static char *connect_to_host(char *host, int port, char **realhost) -{ - SOCKADDR_IN addr; - struct hostent *h; - unsigned long a; -#ifdef FWHACK - char *FWhost; - int FWport; -#endif - - savedhost = malloc(1+strlen(host)); - if (!savedhost) - fatalbox("Out of memory"); - strcpy(savedhost, host); - - if (port < 0) - port = 22; /* default ssh port */ - -#ifdef FWHACK - FWhost = host; - FWport = port; - host = FWSTR; - port = 23; -#endif - - /* - * Try to find host. - */ - if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) { - if ( (h = gethostbyname(host)) == NULL) - switch (WSAGetLastError()) { - case WSAENETDOWN: return "Network is down"; - case WSAHOST_NOT_FOUND: case WSANO_DATA: - return "Host does not exist"; - case WSATRY_AGAIN: return "Host not found"; - default: return "gethostbyname: unknown error"; - } - memcpy (&a, h->h_addr, sizeof(a)); - *realhost = h->h_name; - } else - *realhost = host; -#ifdef FWHACK - *realhost = FWhost; -#endif - a = ntohl(a); - - /* - * Open socket. - */ - s = socket(AF_INET, SOCK_STREAM, 0); - if (s == INVALID_SOCKET) - switch (WSAGetLastError()) { - case WSAENETDOWN: return "Network is down"; - case WSAEAFNOSUPPORT: return "TCP/IP support not present"; - default: return "socket(): unknown error"; - } - - /* - * Bind to local address. - */ - addr.sin_family = AF_INET; - addr.sin_addr.s_addr = htonl(INADDR_ANY); - addr.sin_port = htons(0); - if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR) - switch (WSAGetLastError()) { - case WSAENETDOWN: return "Network is down"; - default: return "bind(): unknown error"; - } - - /* - * Connect to remote address. - */ - addr.sin_addr.s_addr = htonl(a); - addr.sin_port = htons((short)port); - if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR) - switch (WSAGetLastError()) { - case WSAENETDOWN: return "Network is down"; - case WSAECONNREFUSED: return "Connection refused"; - case WSAENETUNREACH: return "Network is unreachable"; - case WSAEHOSTUNREACH: return "No route to host"; - default: return "connect(): unknown error"; - } - -#ifdef FWHACK - send(s, "connect ", 8, 0); - send(s, FWhost, strlen(FWhost), 0); - { - char buf[20]; - sprintf(buf, " %d\n", FWport); - send (s, buf, strlen(buf), 0); - } -#endif - - return NULL; +static void defer_packet(Ssh ssh, int pkttype, ...) +{ + va_list ap1, ap2; + va_start(ap1, pkttype); + va_start(ap2, pkttype); + construct_packet(ssh, pkttype, ap1, ap2); + s_wrpkt_defer(ssh); } -static int ssh_versioncmp(char *a, char *b) { +static int ssh_versioncmp(char *a, char *b) +{ char *ae, *be; unsigned long av, bv; av = strtoul(a, &ae, 10); bv = strtoul(b, &be, 10); - if (av != bv) return (av < bv ? -1 : +1); - if (*ae == '.') ae++; - if (*be == '.') be++; + if (av != bv) + return (av < bv ? -1 : +1); + if (*ae == '.') + ae++; + if (*be == '.') + be++; av = strtoul(ae, &ae, 10); bv = strtoul(be, &be, 10); - if (av != bv) return (av < bv ? -1 : +1); + if (av != bv) + return (av < bv ? -1 : +1); return 0; } - /* - * Utility routine for putting an SSH-protocol `string' into a SHA - * state. + * Utility routines for putting an SSH-protocol `string' and + * `uint32' into a SHA state. */ #include -void sha_string(SHA_State *s, void *str, int len) { +static void sha_string(SHA_State * s, void *str, int len) +{ unsigned char lenblk[4]; PUT_32BIT(lenblk, len); SHA_Bytes(s, lenblk, 4); SHA_Bytes(s, str, len); } +static void sha_uint32(SHA_State * s, unsigned i) +{ + unsigned char intblk[4]; + PUT_32BIT(intblk, i); + SHA_Bytes(s, intblk, 4); +} + /* * SSH2 packet construction functions. */ -void ssh2_pkt_adddata(void *data, int len) { - pktout.length += len; - if (pktout.maxlen < pktout.length) { - pktout.maxlen = pktout.length + 256; - pktout.data = (pktout.data == NULL ? malloc(pktout.maxlen+APIEXTRA) : - realloc(pktout.data, pktout.maxlen+APIEXTRA)); - if (!pktout.data) - fatalbox("Out of memory"); +static void ssh2_pkt_ensure(Ssh ssh, int length) +{ + if (ssh->pktout.maxlen < length) { + ssh->pktout.maxlen = length + 256; + ssh->pktout.data = srealloc(ssh->pktout.data, + ssh->pktout.maxlen + APIEXTRA); + if (!ssh->pktout.data) + fatalbox("Out of memory"); } - memcpy(pktout.data+pktout.length-len, data, len); } -void ssh2_pkt_addbyte(unsigned char byte) { - ssh2_pkt_adddata(&byte, 1); +static void ssh2_pkt_adddata(Ssh ssh, void *data, int len) +{ + ssh->pktout.length += len; + ssh2_pkt_ensure(ssh, ssh->pktout.length); + memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len); +} +static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte) +{ + ssh2_pkt_adddata(ssh, &byte, 1); } -void ssh2_pkt_init(int pkt_type) { - pktout.length = 5; - ssh2_pkt_addbyte((unsigned char)pkt_type); +static void ssh2_pkt_init(Ssh ssh, int pkt_type) +{ + ssh->pktout.length = 5; + ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type); } -void ssh2_pkt_addbool(unsigned char value) { - ssh2_pkt_adddata(&value, 1); +static void ssh2_pkt_addbool(Ssh ssh, unsigned char value) +{ + ssh2_pkt_adddata(ssh, &value, 1); } -void ssh2_pkt_adduint32(unsigned long value) { +static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value) +{ unsigned char x[4]; PUT_32BIT(x, value); - ssh2_pkt_adddata(x, 4); + ssh2_pkt_adddata(ssh, x, 4); } -void ssh2_pkt_addstring_start(void) { - ssh2_pkt_adduint32(0); - pktout.savedpos = pktout.length; +static void ssh2_pkt_addstring_start(Ssh ssh) +{ + ssh2_pkt_adduint32(ssh, 0); + ssh->pktout.savedpos = ssh->pktout.length; } -void ssh2_pkt_addstring_str(char *data) { - ssh2_pkt_adddata(data, strlen(data)); - PUT_32BIT(pktout.data + pktout.savedpos - 4, - pktout.length - pktout.savedpos); +static void ssh2_pkt_addstring_str(Ssh ssh, char *data) +{ + ssh2_pkt_adddata(ssh, data, strlen(data)); + PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4, + ssh->pktout.length - ssh->pktout.savedpos); } -void ssh2_pkt_addstring_data(char *data, int len) { - ssh2_pkt_adddata(data, len); - PUT_32BIT(pktout.data + pktout.savedpos - 4, - pktout.length - pktout.savedpos); +static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len) +{ + ssh2_pkt_adddata(ssh, data, len); + PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4, + ssh->pktout.length - ssh->pktout.savedpos); } -void ssh2_pkt_addstring(char *data) { - ssh2_pkt_addstring_start(); - ssh2_pkt_addstring_str(data); +static void ssh2_pkt_addstring(Ssh ssh, char *data) +{ + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_str(ssh, data); } -char *ssh2_mpint_fmt(Bignum b, int *len) { +static char *ssh2_mpint_fmt(Bignum b, int *len) +{ unsigned char *p; - int i, n = b[0]; - p = malloc(n * 2 + 1); + int i, n = (bignum_bitcount(b) + 7) / 8; + p = smalloc(n + 1); if (!p) - fatalbox("out of memory"); + fatalbox("out of memory"); p[0] = 0; - for (i = 0; i < n; i++) { - p[i*2+1] = (b[n-i] >> 8) & 0xFF; - p[i*2+2] = (b[n-i] ) & 0xFF; - } + for (i = 1; i <= n; i++) + p[i] = bignum_byte(b, n - i); i = 0; - while (p[i] == 0 && (p[i+1] & 0x80) == 0) - i++; - memmove(p, p+i, n*2+1-i); - *len = n*2+1-i; + while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0) + i++; + memmove(p, p + i, n + 1 - i); + *len = n + 1 - i; return p; } -void ssh2_pkt_addmp(Bignum b) { +static void ssh2_pkt_addmp(Ssh ssh, Bignum b) +{ unsigned char *p; int len; p = ssh2_mpint_fmt(b, &len); - ssh2_pkt_addstring_start(); - ssh2_pkt_addstring_data(p, len); - free(p); + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, p, len); + sfree(p); } -void ssh2_pkt_send(void) { + +/* + * Construct an SSH2 final-form packet: compress it, encrypt it, + * put the MAC on it. Final packet, ready to be sent, is stored in + * ssh->pktout.data. Total length is returned. + */ +static int ssh2_pkt_construct(Ssh ssh) +{ int cipherblk, maclen, padding, i; - static unsigned long outgoing_sequence = 0; + + log_packet(PKT_OUTGOING, ssh->pktout.data[5], + ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]), + ssh->pktout.data + 6, ssh->pktout.length - 6); + + /* + * Compress packet payload. + */ + { + unsigned char *newpayload; + int newlen; + if (ssh->cscomp && + ssh->cscomp->compress(ssh->pktout.data + 5, ssh->pktout.length - 5, + &newpayload, &newlen)) { + ssh->pktout.length = 5; + ssh2_pkt_adddata(ssh, newpayload, newlen); + sfree(newpayload); + } + } /* * Add padding. At least four bytes, and must also bring total * length (minus MAC) up to a multiple of the block size. */ - cipherblk = cipher ? cipher->blksize : 8; /* block size */ - cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */ + cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */ + cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */ padding = 4; - padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk; - pktout.data[4] = padding; + padding += + (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk; + maclen = ssh->csmac ? ssh->csmac->len : 0; + ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen); + ssh->pktout.data[4] = padding; for (i = 0; i < padding; i++) - pktout.data[pktout.length + i] = random_byte(); - PUT_32BIT(pktout.data, pktout.length + padding - 4); - if (csmac) - csmac->generate(pktout.data, pktout.length + padding, - outgoing_sequence); - outgoing_sequence++; /* whether or not we MACed */ + ssh->pktout.data[ssh->pktout.length + i] = random_byte(); + PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4); + if (ssh->csmac) + ssh->csmac->generate(ssh->pktout.data, ssh->pktout.length + padding, + ssh->v2_outgoing_sequence); + ssh->v2_outgoing_sequence++; /* whether or not we MACed */ + + if (ssh->cscipher) + ssh->cscipher->encrypt(ssh->pktout.data, ssh->pktout.length + padding); + + /* Ready-to-send packet starts at ssh->pktout.data. We return length. */ + return ssh->pktout.length + padding + maclen; +} -#if 0 - debug(("Sending packet len=%d\r\n", pktout.length+padding)); - for (i = 0; i < pktout.length+padding; i++) - debug((" %02x", (unsigned char)pktout.data[i])); - debug(("\r\n")); -#endif +/* + * Construct and send an SSH2 packet immediately. + */ +static void ssh2_pkt_send(Ssh ssh) +{ + int len; + int backlog; + len = ssh2_pkt_construct(ssh); + backlog = sk_write(ssh->s, ssh->pktout.data, len); + if (backlog > SSH_MAX_BACKLOG) + ssh_throttle_all(ssh, 1, backlog); +} - if (cscipher) - cscipher->encrypt(pktout.data, pktout.length + padding); - maclen = csmac ? csmac->len : 0; +/* + * Construct an SSH2 packet and add it to a deferred data block. + * Useful for sending multiple packets in a single sk_write() call, + * to prevent a traffic-analysing listener from being able to work + * out the length of any particular packet (such as the password + * packet). + * + * Note that because SSH2 sequence-numbers its packets, this can + * NOT be used as an m4-style `defer' allowing packets to be + * constructed in one order and sent in another. + */ +static void ssh2_pkt_defer(Ssh ssh) +{ + int len = ssh2_pkt_construct(ssh); + if (ssh->deferred_len + len > ssh->deferred_size) { + ssh->deferred_size = ssh->deferred_len + len + 128; + ssh->deferred_send_data = srealloc(ssh->deferred_send_data, + ssh->deferred_size); + } + memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len); + ssh->deferred_len += len; +} - s_write(pktout.data, pktout.length + padding + maclen); +/* + * Send the whole deferred data block constructed by + * ssh2_pkt_defer() or SSH1's defer_packet(). + */ +static void ssh_pkt_defersend(Ssh ssh) +{ + int backlog; + backlog = sk_write(ssh->s, ssh->deferred_send_data, ssh->deferred_len); + ssh->deferred_len = ssh->deferred_size = 0; + sfree(ssh->deferred_send_data); + ssh->deferred_send_data = NULL; + if (backlog > SSH_MAX_BACKLOG) + ssh_throttle_all(ssh, 1, backlog); } #if 0 -void bndebug(char *string, Bignum b) { +void bndebug(char *string, Bignum b) +{ unsigned char *p; int i, len; p = ssh2_mpint_fmt(b, &len); debug(("%s", string)); for (i = 0; i < len; i++) - debug((" %02x", p[i])); - debug(("\r\n")); - free(p); + debug((" %02x", p[i])); + debug(("\n")); + sfree(p); } #endif -void sha_mpint(SHA_State *s, Bignum b) { +static void sha_mpint(SHA_State * s, Bignum b) +{ unsigned char *p; int len; p = ssh2_mpint_fmt(b, &len); sha_string(s, p, len); - free(p); + sfree(p); } /* * SSH2 packet decode functions. */ -unsigned long ssh2_pkt_getuint32(void) { +static unsigned long ssh2_pkt_getuint32(Ssh ssh) +{ unsigned long value; - if (pktin.length - pktin.savedpos < 4) - return 0; /* arrgh, no way to decline (FIXME?) */ - value = GET_32BIT(pktin.data+pktin.savedpos); - pktin.savedpos += 4; + if (ssh->pktin.length - ssh->pktin.savedpos < 4) + return 0; /* arrgh, no way to decline (FIXME?) */ + value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos); + ssh->pktin.savedpos += 4; return value; } -void ssh2_pkt_getstring(char **p, int *length) { +static int ssh2_pkt_getbool(Ssh ssh) +{ + unsigned long value; + if (ssh->pktin.length - ssh->pktin.savedpos < 1) + return 0; /* arrgh, no way to decline (FIXME?) */ + value = ssh->pktin.data[ssh->pktin.savedpos] != 0; + ssh->pktin.savedpos++; + return value; +} +static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length) +{ *p = NULL; - if (pktin.length - pktin.savedpos < 4) - return; - *length = GET_32BIT(pktin.data+pktin.savedpos); - pktin.savedpos += 4; - if (pktin.length - pktin.savedpos < *length) - return; - *p = pktin.data+pktin.savedpos; - pktin.savedpos += *length; -} -Bignum ssh2_pkt_getmp(void) { + *length = 0; + if (ssh->pktin.length - ssh->pktin.savedpos < 4) + return; + *length = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos); + ssh->pktin.savedpos += 4; + if (ssh->pktin.length - ssh->pktin.savedpos < *length) + return; + *p = ssh->pktin.data + ssh->pktin.savedpos; + ssh->pktin.savedpos += *length; +} +static Bignum ssh2_pkt_getmp(Ssh ssh) +{ char *p; - int i, j, length; + int length; Bignum b; - ssh2_pkt_getstring(&p, &length); + ssh2_pkt_getstring(ssh, &p, &length); if (!p) - return NULL; - if (p[0] & 0x80) - fatalbox("internal error: Can't handle negative mpints"); - b = newbn((length+1)/2); - for (i = 0; i < length; i++) { - j = length - 1 - i; - if (j & 1) - b[j/2+1] |= ((unsigned char)p[i]) << 8; - else - b[j/2+1] |= ((unsigned char)p[i]); + return NULL; + if (p[0] & 0x80) { + bombout(("internal error: Can't handle negative mpints")); + return NULL; } + b = bignum_from_bytes(p, length); return b; } -static int do_ssh_init(void) { - char c, *vsp; - char version[10]; - char vstring[80]; - char vlog[sizeof(vstring)+20]; - int i; +/* + * Helper function to add an SSH2 signature blob to a packet. + * Expects to be shown the public key blob as well as the signature + * blob. Normally works just like ssh2_pkt_addstring, but will + * fiddle with the signature packet if necessary for + * BUG_SSH2_RSA_PADDING. + */ +static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len, + void *sigblob_v, int sigblob_len) +{ + unsigned char *pkblob = (unsigned char *)pkblob_v; + unsigned char *sigblob = (unsigned char *)sigblob_v; -#ifdef FWHACK - i = 0; - while (s_read(&c, 1) == 1) { - if (c == 'S' && i < 2) i++; - else if (c == 'S' && i == 2) i = 2; - else if (c == 'H' && i == 2) break; - else i = 0; + /* dmemdump(pkblob, pkblob_len); */ + /* dmemdump(sigblob, sigblob_len); */ + + /* + * See if this is in fact an ssh-rsa signature and a buggy + * server; otherwise we can just do this the easy way. + */ + if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) && + (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) { + int pos, len, siglen; + + /* + * Find the byte length of the modulus. + */ + + pos = 4+7; /* skip over "ssh-rsa" */ + pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */ + len = GET_32BIT(pkblob+pos); /* find length of modulus */ + pos += 4; /* find modulus itself */ + while (len > 0 && pkblob[pos] == 0) + len--, pos++; + /* debug(("modulus length is %d\n", len)); */ + + /* + * Now find the signature integer. + */ + pos = 4+7; /* skip over "ssh-rsa" */ + siglen = GET_32BIT(sigblob+pos); + /* debug(("signature length is %d\n", siglen)); */ + + if (len != siglen) { + unsigned char newlen[4]; + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, sigblob, pos); + /* dmemdump(sigblob, pos); */ + pos += 4; /* point to start of actual sig */ + PUT_32BIT(newlen, len); + ssh2_pkt_addstring_data(ssh, newlen, 4); + /* dmemdump(newlen, 4); */ + newlen[0] = 0; + while (len-- > siglen) { + ssh2_pkt_addstring_data(ssh, newlen, 1); + /* dmemdump(newlen, 1); */ + } + ssh2_pkt_addstring_data(ssh, sigblob+pos, siglen); + /* dmemdump(sigblob+pos, siglen); */ + return; + } + + /* Otherwise fall through and do it the easy way. */ } -#else - if (s_read(&c,1) != 1 || c != 'S') return 0; - if (s_read(&c,1) != 1 || c != 'S') return 0; - if (s_read(&c,1) != 1 || c != 'H') return 0; -#endif - strcpy(vstring, "SSH-"); - vsp = vstring+4; - if (s_read(&c,1) != 1 || c != '-') return 0; - i = 0; + + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, sigblob, sigblob_len); +} + +/* + * Examine the remote side's version string and compare it against + * a list of known buggy implementations. + */ +static void ssh_detect_bugs(Ssh ssh, char *vstring) +{ + char *imp; /* pointer to implementation part */ + imp = vstring; + imp += strcspn(imp, "-"); + if (*imp) imp++; + imp += strcspn(imp, "-"); + if (*imp) imp++; + + ssh->remote_bugs = 0; + + if (cfg.sshbug_ignore1 == BUG_ON || + (cfg.sshbug_ignore1 == BUG_AUTO && + (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") || + !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") || + !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) { + /* + * These versions don't support SSH1_MSG_IGNORE, so we have + * to use a different defence against password length + * sniffing. + */ + ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE; + logevent("We believe remote version has SSH1 ignore bug"); + } + + if (cfg.sshbug_plainpw1 == BUG_ON || + (cfg.sshbug_plainpw1 == BUG_AUTO && + (!strcmp(imp, "Cisco-1.25")))) { + /* + * These versions need a plain password sent; they can't + * handle having a null and a random length of data after + * the password. + */ + ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD; + logevent("We believe remote version needs a plain SSH1 password"); + } + + if (cfg.sshbug_rsa1 == BUG_ON || + (cfg.sshbug_rsa1 == BUG_AUTO && + (!strcmp(imp, "Cisco-1.25")))) { + /* + * These versions apparently have no clue whatever about + * RSA authentication and will panic and die if they see + * an AUTH_RSA message. + */ + ssh->remote_bugs |= BUG_CHOKES_ON_RSA; + logevent("We believe remote version can't handle RSA authentication"); + } + + if (cfg.sshbug_hmac2 == BUG_ON || + (cfg.sshbug_hmac2 == BUG_AUTO && + (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) || + !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) || + !strncmp(imp, "2.1 ", 4)))) { + /* + * These versions have the HMAC bug. + */ + ssh->remote_bugs |= BUG_SSH2_HMAC; + logevent("We believe remote version has SSH2 HMAC bug"); + } + + if (cfg.sshbug_derivekey2 == BUG_ON || + (cfg.sshbug_derivekey2 == BUG_AUTO && + (!strncmp(imp, "2.0.", 4)))) { + /* + * These versions have the key-derivation bug (failing to + * include the literal shared secret in the hashes that + * generate the keys). + */ + ssh->remote_bugs |= BUG_SSH2_DERIVEKEY; + logevent("We believe remote version has SSH2 key-derivation bug"); + } + + if (cfg.sshbug_rsapad2 == BUG_ON || + (cfg.sshbug_rsapad2 == BUG_AUTO && + ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') || + (!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')))){ + /* + * These versions have the SSH2 RSA padding bug. + */ + ssh->remote_bugs |= BUG_SSH2_RSA_PADDING; + logevent("We believe remote version has SSH2 RSA padding bug"); + } + + if (cfg.sshbug_dhgex2 == BUG_ON) { + /* + * These versions have the SSH2 DH GEX bug. + */ + ssh->remote_bugs |= BUG_SSH2_DH_GEX; + logevent("We believe remote version has SSH2 DH group exchange bug"); + } +} + +static int do_ssh_init(Ssh ssh, unsigned char c) +{ + struct do_ssh_init_state { + int vslen; + char version[10]; + char *vstring; + int vstrsize; + int i; + int proto1, proto2; + }; + crState(do_ssh_init_state); + + crBegin(ssh->do_ssh_init_crstate); + + /* Search for the string "SSH-" in the input. */ + s->i = 0; while (1) { - if (s_read(&c,1) != 1) - return 0; - if (vsp < vstring+sizeof(vstring)-1) - *vsp++ = c; - if (i >= 0) { - if (c == '-') { - version[i] = '\0'; - i = -1; - } else if (i < sizeof(version)-1) - version[i++] = c; + static const int transS[] = { 1, 2, 2, 1 }; + static const int transH[] = { 0, 0, 3, 0 }; + static const int transminus[] = { 0, 0, 0, -1 }; + if (c == 'S') + s->i = transS[s->i]; + else if (c == 'H') + s->i = transH[s->i]; + else if (c == '-') + s->i = transminus[s->i]; + else + s->i = 0; + if (s->i < 0) + break; + crReturn(1); /* get another character */ + } + + s->vstrsize = 16; + s->vstring = smalloc(s->vstrsize); + strcpy(s->vstring, "SSH-"); + s->vslen = 4; + s->i = 0; + while (1) { + crReturn(1); /* get another char */ + if (s->vslen >= s->vstrsize - 1) { + s->vstrsize += 16; + s->vstring = srealloc(s->vstring, s->vstrsize); } - else if (c == '\n') + s->vstring[s->vslen++] = c; + if (s->i >= 0) { + if (c == '-') { + s->version[s->i] = '\0'; + s->i = -1; + } else if (s->i < sizeof(s->version) - 1) + s->version[s->i++] = c; + } else if (c == '\n') break; } - *vsp = 0; - sprintf(vlog, "Server version: %s", vstring); - vlog[strcspn(vlog, "\r\n")] = '\0'; - logevent(vlog); + ssh->agentfwd_enabled = FALSE; + ssh->rdpkt2_state.incoming_sequence = 0; + + s->vstring[s->vslen] = 0; + s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */ + { + char *vlog; + vlog = smalloc(20 + s->vslen); + sprintf(vlog, "Server version: %s", s->vstring); + logevent(vlog); + sfree(vlog); + } + ssh_detect_bugs(ssh, s->vstring); /* - * Server version "1.99" means we can choose whether we use v1 - * or v2 protocol. Choice is based on cfg.sshprot. + * Decide which SSH protocol version to support. */ - if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) { - /* - * This is a v2 server. Begin v2 protocol. - */ - char *verstring = "SSH-2.0-PuTTY"; - SHA_Init(&exhash); - /* - * Hash our version string and their version string. - */ - sha_string(&exhash, verstring, strlen(verstring)); - sha_string(&exhash, vstring, strcspn(vstring, "\r\n")); - sprintf(vstring, "%s\n", verstring); - sprintf(vlog, "We claim version: %s", verstring); - logevent(vlog); - logevent("Using SSH protocol version 2"); - s_write(vstring, strlen(vstring)); - ssh_protocol = ssh2_protocol; - ssh_version = 2; - s_rdpkt = ssh2_rdpkt; + + /* Anything strictly below "2.0" means protocol 1 is supported. */ + s->proto1 = ssh_versioncmp(s->version, "2.0") < 0; + /* Anything greater or equal to "1.99" means protocol 2 is supported. */ + s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0; + + if (cfg.sshprot == 0 && !s->proto1) { + bombout(("SSH protocol version 1 required by user but not provided by server")); + crReturn(0); + } + if (cfg.sshprot == 3 && !s->proto2) { + bombout(("SSH protocol version 2 required by user but not provided by server")); + crReturn(0); + } + + if (s->proto2 && (cfg.sshprot >= 2 || !s->proto1)) { + /* + * Use v2 protocol. + */ + char verstring[80], vlog[100]; + sprintf(verstring, "SSH-2.0-%s", sshver); + SHA_Init(&ssh->exhashbase); + /* + * Hash our version string and their version string. + */ + sha_string(&ssh->exhashbase, verstring, strlen(verstring)); + sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n")); + sprintf(vlog, "We claim version: %s", verstring); + logevent(vlog); + strcat(verstring, "\n"); + logevent("Using SSH protocol version 2"); + sk_write(ssh->s, verstring, strlen(verstring)); + ssh->protocol = ssh2_protocol; + ssh->version = 2; + ssh->s_rdpkt = ssh2_rdpkt; } else { - /* - * This is a v1 server. Begin v1 protocol. - */ - sprintf(vstring, "SSH-%s-PuTTY\n", - (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5")); - sprintf(vlog, "We claim version: %s", vstring); - vlog[strcspn(vlog, "\r\n")] = '\0'; - logevent(vlog); - logevent("Using SSH protocol version 1"); - s_write(vstring, strlen(vstring)); - ssh_protocol = ssh1_protocol; - ssh_version = 1; - s_rdpkt = ssh1_rdpkt; - } - ssh_send_ok = 0; + /* + * Use v1 protocol. + */ + char verstring[80], vlog[100]; + sprintf(verstring, "SSH-%s-%s", + (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"), + sshver); + sprintf(vlog, "We claim version: %s", verstring); + logevent(vlog); + strcat(verstring, "\n"); + + logevent("Using SSH protocol version 1"); + sk_write(ssh->s, verstring, strlen(verstring)); + ssh->protocol = ssh1_protocol; + ssh->version = 1; + ssh->s_rdpkt = ssh1_rdpkt; + } + ssh->state = SSH_STATE_BEFORE_SIZE; + + sfree(s->vstring); + + crFinish(0); +} + +static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen) +{ + crBegin(ssh->ssh_gotdata_crstate); + + /* + * To begin with, feed the characters one by one to the + * protocol initialisation / selection function do_ssh_init(). + * When that returns 0, we're done with the initial greeting + * exchange and can move on to packet discipline. + */ + while (1) { + int ret; /* need not be kept across crReturn */ + if (datalen == 0) + crReturnV; /* more data please */ + ret = do_ssh_init(ssh, *data); + data++; + datalen--; + if (ret == 0) + break; + } + + /* + * We emerge from that loop when the initial negotiation is + * over and we have selected an s_rdpkt function. Now pass + * everything to s_rdpkt, and then pass the resulting packets + * to the proper protocol handler. + */ + if (datalen == 0) + crReturnV; + while (1) { + while (datalen > 0) { + if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) { + if (ssh->state == SSH_STATE_CLOSED) { + return; + } + ssh->protocol(ssh, NULL, 0, 1); + if (ssh->state == SSH_STATE_CLOSED) { + return; + } + } + } + crReturnV; + } + crFinishV; +} + +static int ssh_closing(Plug plug, char *error_msg, int error_code, + int calling_back) +{ + Ssh ssh = (Ssh) plug; + ssh->state = SSH_STATE_CLOSED; + if (ssh->s) { + sk_close(ssh->s); + ssh->s = NULL; + } + if (error_msg) { + /* A socket error has occurred. */ + logevent(error_msg); + connection_fatal(error_msg); + } else { + /* Otherwise, the remote side closed the connection normally. */ + } + return 0; +} + +static int ssh_receive(Plug plug, int urgent, char *data, int len) +{ + Ssh ssh = (Ssh) plug; + ssh_gotdata(ssh, data, len); + if (ssh->state == SSH_STATE_CLOSED) { + if (ssh->s) { + sk_close(ssh->s); + ssh->s = NULL; + } + return 0; + } return 1; } +static void ssh_sent(Plug plug, int bufsize) +{ + Ssh ssh = (Ssh) plug; + /* + * If the send backlog on the SSH socket itself clears, we + * should unthrottle the whole world if it was throttled. + */ + if (bufsize < SSH_MAX_BACKLOG) + ssh_throttle_all(ssh, 0, bufsize); +} + +/* + * Connect to specified host and port. + * Returns an error message, or NULL on success. + * Also places the canonical host name into `realhost'. It must be + * freed by the caller. + */ +static char *connect_to_host(Ssh ssh, char *host, int port, + char **realhost, int nodelay) +{ + static const struct plug_function_table fn_table = { + ssh_closing, + ssh_receive, + ssh_sent, + NULL + }; + + SockAddr addr; + char *err; + + ssh->savedhost = smalloc(1 + strlen(host)); + if (!ssh->savedhost) + fatalbox("Out of memory"); + strcpy(ssh->savedhost, host); + + if (port < 0) + port = 22; /* default ssh port */ + ssh->savedport = port; + + /* + * Try to find host. + */ + { + char buf[200]; + sprintf(buf, "Looking up host \"%.170s\"", host); + logevent(buf); + } + addr = sk_namelookup(host, realhost); + if ((err = sk_addr_error(addr))) + return err; + + /* + * Open socket. + */ + { + char buf[200], addrbuf[100]; + sk_getaddr(addr, addrbuf, 100); + sprintf(buf, "Connecting to %.100s port %d", addrbuf, port); + logevent(buf); + } + ssh->fn = &fn_table; + ssh->s = new_connection(addr, *realhost, port, 0, 1, nodelay, (Plug) ssh); + if ((err = sk_socket_error(ssh->s))) { + ssh->s = NULL; + return err; + } + + return NULL; +} + +/* + * Throttle or unthrottle the SSH connection. + */ +static void ssh1_throttle(Ssh ssh, int adjust) +{ + int old_count = ssh->v1_throttle_count; + ssh->v1_throttle_count += adjust; + assert(ssh->v1_throttle_count >= 0); + if (ssh->v1_throttle_count && !old_count) { + sk_set_frozen(ssh->s, 1); + } else if (!ssh->v1_throttle_count && old_count) { + sk_set_frozen(ssh->s, 0); + } +} + +/* + * Throttle or unthrottle _all_ local data streams (for when sends + * on the SSH connection itself back up). + */ +static void ssh_throttle_all(Ssh ssh, int enable, int bufsize) +{ + int i; + struct ssh_channel *c; + + if (enable == ssh->throttled_all) + return; + ssh->throttled_all = enable; + ssh->overall_bufsize = bufsize; + if (!ssh->channels) + return; + for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) { + switch (c->type) { + case CHAN_MAINSESSION: + /* + * This is treated separately, outside the switch. + */ + break; + case CHAN_X11: + x11_override_throttle(c->u.x11.s, enable); + break; + case CHAN_AGENT: + /* Agent channels require no buffer management. */ + break; + case CHAN_SOCKDATA: + pfd_override_throttle(c->u.x11.s, enable); + break; + } + } +} + +/* + * Username and password input, abstracted off into routines + * reusable in several places - even between SSH1 and SSH2. + */ + +/* Set up a username or password input loop on a given buffer. */ +void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo) +{ + ssh->userpass_input_buffer = buffer; + ssh->userpass_input_buflen = buflen; + ssh->userpass_input_bufpos = 0; + ssh->userpass_input_echo = echo; +} + +/* + * Process some terminal data in the course of username/password + * input. Returns >0 for success (line of input returned in + * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0 + * for inconclusive (keep waiting for more input please). + */ +int process_userpass_input(Ssh ssh, unsigned char *in, int inlen) +{ + char c; + + while (inlen--) { + switch (c = *in++) { + case 10: + case 13: + ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0; + ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0; + return +1; + break; + case 8: + case 127: + if (ssh->userpass_input_bufpos > 0) { + if (ssh->userpass_input_echo) + c_write_str(ssh, "\b \b"); + ssh->userpass_input_bufpos--; + } + break; + case 21: + case 27: + while (ssh->userpass_input_bufpos > 0) { + if (ssh->userpass_input_echo) + c_write_str(ssh, "\b \b"); + ssh->userpass_input_bufpos--; + } + break; + case 3: + case 4: + return -1; + break; + default: + if (((c >= ' ' && c <= '~') || + ((unsigned char) c >= 160)) + && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) { + ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c; + if (ssh->userpass_input_echo) + c_write(ssh, &c, 1); + } + break; + } + } + return 0; +} + /* * Handle the key exchange and user authentication phases. */ -static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) +static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt) { - int i, j, len; - unsigned char *rsabuf, *keystr1, *keystr2; + int i, j; unsigned char cookie[8]; struct RSAKey servkey, hostkey; struct MD5Context md5c; - static unsigned long supported_ciphers_mask, supported_auths_mask; - static int tried_publickey; - static unsigned char session_id[16]; - int cipher_type; - - crBegin; - - if (!ispkt) crWaitUntil(ispkt); + struct do_ssh1_login_state { + int len; + unsigned char *rsabuf, *keystr1, *keystr2; + unsigned long supported_ciphers_mask, supported_auths_mask; + int tried_publickey, tried_agent; + int tis_auth_refused, ccard_auth_refused; + unsigned char session_id[16]; + int cipher_type; + char username[100]; + void *publickey_blob; + int publickey_bloblen; + char password[100]; + char prompt[200]; + int pos; + char c; + int pwpkt_type; + unsigned char request[5], *response, *p; + int responselen; + int keyi, nkeys; + int authed; + struct RSAKey key; + Bignum challenge; + char *commentp; + int commentlen; + }; + crState(do_ssh1_login_state); + + crBegin(ssh->do_ssh1_login_crstate); + + if (!ispkt) + crWaitUntil(ispkt); - if (pktin.type != SSH1_SMSG_PUBLIC_KEY) - fatalbox("Public key packet not received"); + if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) { + bombout(("Public key packet not received")); + crReturn(0); + } logevent("Received public keys"); - memcpy(cookie, pktin.body, 8); + memcpy(cookie, ssh->pktin.body, 8); - i = makekey(pktin.body+8, &servkey, &keystr1, 0); - j = makekey(pktin.body+8+i, &hostkey, &keystr2, 0); + i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0); + j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0); /* - * Hash the host key and print the hash in the log box. Just as - * a last resort in case the registry's host key checking is - * compromised, we'll allow the user some ability to verify - * host keys by eye. + * Log the host key fingerprint. */ - MD5Init(&md5c); - MD5Update(&md5c, keystr2, hostkey.bytes); - MD5Final(session_id, &md5c); { char logmsg[80]; - int i; - logevent("Host key MD5 is:"); + logevent("Host key fingerprint is:"); strcpy(logmsg, " "); - for (i = 0; i < 16; i++) - sprintf(logmsg+strlen(logmsg), "%02x", session_id[i]); + hostkey.comment = NULL; + rsa_fingerprint(logmsg + strlen(logmsg), + sizeof(logmsg) - strlen(logmsg), &hostkey); logevent(logmsg); } - supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j); - supported_auths_mask = GET_32BIT(pktin.body+16+i+j); + ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j); + s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j); + s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j); + + ssh->v1_local_protoflags = + ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED; + ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER; MD5Init(&md5c); - MD5Update(&md5c, keystr2, hostkey.bytes); - MD5Update(&md5c, keystr1, servkey.bytes); - MD5Update(&md5c, pktin.body, 8); - MD5Final(session_id, &md5c); + MD5Update(&md5c, s->keystr2, hostkey.bytes); + MD5Update(&md5c, s->keystr1, servkey.bytes); + MD5Update(&md5c, ssh->pktin.body, 8); + MD5Final(s->session_id, &md5c); - for (i=0; i<32; i++) - session_key[i] = random_byte(); + for (i = 0; i < 32; i++) + ssh->session_key[i] = random_byte(); - len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes); + s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes); - rsabuf = malloc(len); - if (!rsabuf) + s->rsabuf = smalloc(s->len); + if (!s->rsabuf) fatalbox("Out of memory"); /* * Verify the host key. */ { - /* - * First format the key into a string. - */ - int len = rsastr_len(&hostkey); - char *keystr = malloc(len); - if (!keystr) - fatalbox("Out of memory"); - rsastr_fmt(keystr, &hostkey); - verify_ssh_host_key(savedhost, keystr); - free(keystr); + /* + * First format the key into a string. + */ + int len = rsastr_len(&hostkey); + char fingerprint[100]; + char *keystr = smalloc(len); + if (!keystr) + fatalbox("Out of memory"); + rsastr_fmt(keystr, &hostkey); + rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey); + verify_ssh_host_key(ssh->savedhost, ssh->savedport, "rsa", keystr, + fingerprint); + sfree(keystr); } - for (i=0; i<32; i++) { - rsabuf[i] = session_key[i]; + for (i = 0; i < 32; i++) { + s->rsabuf[i] = ssh->session_key[i]; if (i < 16) - rsabuf[i] ^= session_id[i]; + s->rsabuf[i] ^= s->session_id[i]; } if (hostkey.bytes > servkey.bytes) { - rsaencrypt(rsabuf, 32, &servkey); - rsaencrypt(rsabuf, servkey.bytes, &hostkey); + rsaencrypt(s->rsabuf, 32, &servkey); + rsaencrypt(s->rsabuf, servkey.bytes, &hostkey); } else { - rsaencrypt(rsabuf, 32, &hostkey); - rsaencrypt(rsabuf, hostkey.bytes, &servkey); + rsaencrypt(s->rsabuf, 32, &hostkey); + rsaencrypt(s->rsabuf, hostkey.bytes, &servkey); } logevent("Encrypted session key"); - cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH : - cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES : - SSH_CIPHER_3DES; - if ((supported_ciphers_mask & (1 << cipher_type)) == 0) { - c_write("Selected cipher not supported, falling back to 3DES\r\n", 53); - cipher_type = SSH_CIPHER_3DES; + { + int cipher_chosen = 0, warn = 0; + char *cipher_string = NULL; + int i; + for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) { + int next_cipher = cfg.ssh_cipherlist[i]; + if (next_cipher == CIPHER_WARN) { + /* If/when we choose a cipher, warn about it */ + warn = 1; + } else if (next_cipher == CIPHER_AES) { + /* XXX Probably don't need to mention this. */ + logevent("AES not supported in SSH1, skipping"); + } else { + switch (next_cipher) { + case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES; + cipher_string = "3DES"; break; + case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH; + cipher_string = "Blowfish"; break; + case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES; + cipher_string = "single-DES"; break; + } + if (s->supported_ciphers_mask & (1 << s->cipher_type)) + cipher_chosen = 1; + } + } + if (!cipher_chosen) { + if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0) + bombout(("Server violates SSH 1 protocol by not " + "supporting 3DES encryption")); + else + /* shouldn't happen */ + bombout(("No supported ciphers found")); + crReturn(0); + } + + /* Warn about chosen cipher if necessary. */ + if (warn) + askcipher(cipher_string, 0); } - switch (cipher_type) { - case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break; - case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break; - case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break; + + switch (s->cipher_type) { + case SSH_CIPHER_3DES: + logevent("Using 3DES encryption"); + break; + case SSH_CIPHER_DES: + logevent("Using single-DES encryption"); + break; + case SSH_CIPHER_BLOWFISH: + logevent("Using Blowfish encryption"); + break; } - send_packet(SSH1_CMSG_SESSION_KEY, - PKT_CHAR, cipher_type, - PKT_DATA, cookie, 8, - PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF, - PKT_DATA, rsabuf, len, - PKT_INT, 0, - PKT_END); + send_packet(ssh, SSH1_CMSG_SESSION_KEY, + PKT_CHAR, s->cipher_type, + PKT_DATA, cookie, 8, + PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF, + PKT_DATA, s->rsabuf, s->len, + PKT_INT, ssh->v1_local_protoflags, PKT_END); logevent("Trying to enable encryption..."); - free(rsabuf); + sfree(s->rsabuf); - cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish : - cipher_type == SSH_CIPHER_DES ? &ssh_des : - &ssh_3des; - cipher->sesskey(session_key); + ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 : + s->cipher_type == SSH_CIPHER_DES ? &ssh_des : + &ssh_3des); + ssh->cipher->sesskey(ssh->session_key); crWaitUntil(ispkt); - if (pktin.type != SSH1_SMSG_SUCCESS) - fatalbox("Encryption not successfully enabled"); + if (ssh->pktin.type != SSH1_SMSG_SUCCESS) { + bombout(("Encryption not successfully enabled")); + crReturn(0); + } logevent("Successfully started encryption"); fflush(stdout); { - static char username[100]; - static int pos = 0; - static char c; - if ((flags & FLAG_CONNECTION) && !*cfg.username) { - c_write("login as: ", 10); - while (pos >= 0) { - crWaitUntil(!ispkt); - while (inlen--) switch (c = *in++) { - case 10: case 13: - username[pos] = 0; - pos = -1; - break; - case 8: case 127: - if (pos > 0) { - c_write("\b \b", 3); - pos--; - } - break; - case 21: case 27: - while (pos > 0) { - c_write("\b \b", 3); - pos--; - } - break; - case 3: case 4: - random_save_seed(); - exit(0); - break; - default: - if (((c >= ' ' && c <= '~') || - ((unsigned char)c >= 160)) && pos < 40) { - username[pos++] = c; - c_write(&c, 1); - } - break; + if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { + if (ssh_get_line && !ssh_getline_pw_only) { + if (!ssh_get_line("login as: ", + s->username, sizeof(s->username), FALSE)) { + /* + * get_line failed to get a username. + * Terminate. + */ + logevent("No username provided. Abandoning session."); + ssh->state = SSH_STATE_CLOSED; + crReturn(1); } + } else { + int ret; /* need not be kept over crReturn */ + c_write_str(ssh, "login as: "); + ssh->send_ok = 1; + + setup_userpass_input(ssh, s->username, sizeof(s->username), 1); + do { + crWaitUntil(!ispkt); + ret = process_userpass_input(ssh, in, inlen); + } while (ret == 0); + if (ret < 0) + cleanup_exit(0); + c_write_str(ssh, "\r\n"); } - c_write("\r\n", 2); - username[strcspn(username, "\n\r")] = '\0'; } else { - char stuff[200]; - strncpy(username, cfg.username, 99); - username[99] = '\0'; - if (flags & FLAG_VERBOSE) { - sprintf(stuff, "Sent username \"%s\".\r\n", username); - c_write(stuff, strlen(stuff)); - } + strncpy(s->username, cfg.username, sizeof(s->username)); + s->username[sizeof(s->username)-1] = '\0'; } - send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END); + send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END); { - char userlog[20+sizeof(username)]; - sprintf(userlog, "Sent username \"%s\"", username); + char userlog[22 + sizeof(s->username)]; + sprintf(userlog, "Sent username \"%s\"", s->username); logevent(userlog); + if (flags & FLAG_INTERACTIVE && + (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) { + strcat(userlog, "\r\n"); + c_write_str(ssh, userlog); + } } } crWaitUntil(ispkt); - tried_publickey = 0; - - while (pktin.type == SSH1_SMSG_FAILURE) { - static char password[100]; - static int pos; - static char c; - static int pwpkt_type; - /* - * Show password prompt, having first obtained it via a TIS - * or CryptoCard exchange if we're doing TIS or CryptoCard - * authentication. - */ - pwpkt_type = SSH1_CMSG_AUTH_PASSWORD; - if (agent_exists()) { - /* - * Attempt RSA authentication using Pageant. - */ - static unsigned char request[5], *response, *p; - static int responselen; - static int i, nkeys; - static int authed = FALSE; - void *r; - - logevent("Pageant is running. Requesting keys."); - - /* Request the keys held by the agent. */ - PUT_32BIT(request, 1); - request[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES; - agent_query(request, 5, &r, &responselen); - response = (unsigned char *)r; - if (response) { - p = response + 5; - nkeys = GET_32BIT(p); p += 4; - { char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys); - logevent(buf); } - for (i = 0; i < nkeys; i++) { - static struct RSAKey key; - static Bignum challenge; - - { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i); - logevent(buf); } - p += 4; - p += ssh1_read_bignum(p, &key.exponent); - p += ssh1_read_bignum(p, &key.modulus); - send_packet(SSH1_CMSG_AUTH_RSA, - PKT_BIGNUM, key.modulus, PKT_END); - crWaitUntil(ispkt); - if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) { - logevent("Key refused"); - continue; - } - logevent("Received RSA challenge"); - ssh1_read_bignum(pktin.body, &challenge); - { - char *agentreq, *q, *ret; - int len, retlen; - len = 1 + 4; /* message type, bit count */ - len += ssh1_bignum_length(key.exponent); - len += ssh1_bignum_length(key.modulus); - len += ssh1_bignum_length(challenge); - len += 16; /* session id */ - len += 4; /* response format */ - agentreq = malloc(4 + len); - PUT_32BIT(agentreq, len); - q = agentreq + 4; - *q++ = SSH_AGENTC_RSA_CHALLENGE; - PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus)); - q += 4; - q += ssh1_write_bignum(q, key.exponent); - q += ssh1_write_bignum(q, key.modulus); - q += ssh1_write_bignum(q, challenge); - memcpy(q, session_id, 16); q += 16; - PUT_32BIT(q, 1); /* response format */ - agent_query(agentreq, len+4, &ret, &retlen); - free(agentreq); - if (ret) { - if (ret[4] == SSH_AGENT_RSA_RESPONSE) { - logevent("Sending Pageant's response"); - send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE, - PKT_DATA, ret+5, 16, PKT_END); - free(ret); - crWaitUntil(ispkt); - if (pktin.type == SSH1_SMSG_SUCCESS) { - logevent("Pageant's response accepted"); - authed = TRUE; - } else - logevent("Pageant's response not accepted"); - } else { - logevent("Pageant failed to answer challenge"); - free(ret); - } - } else { - logevent("No reply received from Pageant"); - } - } - freebn(key.exponent); - freebn(key.modulus); - freebn(challenge); - if (authed) - break; - } - } - if (authed) - break; - } - if (*cfg.keyfile && !tried_publickey) - pwpkt_type = SSH1_CMSG_AUTH_RSA; + if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) { + /* We must not attempt PK auth. Pretend we've already tried it. */ + s->tried_publickey = s->tried_agent = 1; + } else { + s->tried_publickey = s->tried_agent = 0; + } + s->tis_auth_refused = s->ccard_auth_refused = 0; + /* Load the public half of cfg.keyfile so we notice if it's in Pageant */ + if (*cfg.keyfile) { + if (!rsakey_pubblob(cfg.keyfile, + &s->publickey_blob, &s->publickey_bloblen)) + s->publickey_blob = NULL; + } else + s->publickey_blob = NULL; + + while (ssh->pktin.type == SSH1_SMSG_FAILURE) { + s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD; + + if (agent_exists() && !s->tried_agent) { + /* + * Attempt RSA authentication using Pageant. + */ + void *r; + + s->authed = FALSE; + s->tried_agent = 1; + logevent("Pageant is running. Requesting keys."); + + /* Request the keys held by the agent. */ + PUT_32BIT(s->request, 1); + s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES; + agent_query(s->request, 5, &r, &s->responselen); + s->response = (unsigned char *) r; + if (s->response && s->responselen >= 5 && + s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) { + s->p = s->response + 5; + s->nkeys = GET_32BIT(s->p); + s->p += 4; + { + char buf[64]; + sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys); + logevent(buf); + } + for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) { + { + char buf[64]; + sprintf(buf, "Trying Pageant key #%d", s->keyi); + logevent(buf); + } + if (s->publickey_blob && + !memcmp(s->p, s->publickey_blob, + s->publickey_bloblen)) { + logevent("This key matches configured key file"); + s->tried_publickey = 1; + } + s->p += 4; + s->p += ssh1_read_bignum(s->p, &s->key.exponent); + s->p += ssh1_read_bignum(s->p, &s->key.modulus); + s->commentlen = GET_32BIT(s->p); + s->p += 4; + s->commentp = s->p; + s->p += s->commentlen; + send_packet(ssh, SSH1_CMSG_AUTH_RSA, + PKT_BIGNUM, s->key.modulus, PKT_END); + crWaitUntil(ispkt); + if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) { + logevent("Key refused"); + continue; + } + logevent("Received RSA challenge"); + ssh1_read_bignum(ssh->pktin.body, &s->challenge); + { + char *agentreq, *q, *ret; + void *vret; + int len, retlen; + len = 1 + 4; /* message type, bit count */ + len += ssh1_bignum_length(s->key.exponent); + len += ssh1_bignum_length(s->key.modulus); + len += ssh1_bignum_length(s->challenge); + len += 16; /* session id */ + len += 4; /* response format */ + agentreq = smalloc(4 + len); + PUT_32BIT(agentreq, len); + q = agentreq + 4; + *q++ = SSH1_AGENTC_RSA_CHALLENGE; + PUT_32BIT(q, bignum_bitcount(s->key.modulus)); + q += 4; + q += ssh1_write_bignum(q, s->key.exponent); + q += ssh1_write_bignum(q, s->key.modulus); + q += ssh1_write_bignum(q, s->challenge); + memcpy(q, s->session_id, 16); + q += 16; + PUT_32BIT(q, 1); /* response format */ + agent_query(agentreq, len + 4, &vret, &retlen); + ret = vret; + sfree(agentreq); + if (ret) { + if (ret[4] == SSH1_AGENT_RSA_RESPONSE) { + logevent("Sending Pageant's response"); + send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE, + PKT_DATA, ret + 5, 16, + PKT_END); + sfree(ret); + crWaitUntil(ispkt); + if (ssh->pktin.type == SSH1_SMSG_SUCCESS) { + logevent + ("Pageant's response accepted"); + if (flags & FLAG_VERBOSE) { + c_write_str(ssh, "Authenticated using" + " RSA key \""); + c_write(ssh, s->commentp, + s->commentlen); + c_write_str(ssh, "\" from agent\r\n"); + } + s->authed = TRUE; + } else + logevent + ("Pageant's response not accepted"); + } else { + logevent + ("Pageant failed to answer challenge"); + sfree(ret); + } + } else { + logevent("No reply received from Pageant"); + } + } + freebn(s->key.exponent); + freebn(s->key.modulus); + freebn(s->challenge); + if (s->authed) + break; + } + } + if (s->authed) + break; + } + if (*cfg.keyfile && !s->tried_publickey) + s->pwpkt_type = SSH1_CMSG_AUTH_RSA; + + if (cfg.try_tis_auth && + (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) && + !s->tis_auth_refused) { + s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE; + logevent("Requested TIS authentication"); + send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END); + crWaitUntil(ispkt); + if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) { + logevent("TIS authentication declined"); + if (flags & FLAG_INTERACTIVE) + c_write_str(ssh, "TIS authentication refused.\r\n"); + s->tis_auth_refused = 1; + continue; + } else { + int challengelen = GET_32BIT(ssh->pktin.body); + logevent("Received TIS challenge"); + if (challengelen > sizeof(s->prompt) - 1) + challengelen = sizeof(s->prompt) - 1;/* prevent overrun */ + memcpy(s->prompt, ssh->pktin.body + 4, challengelen); + /* Prompt heuristic comes from OpenSSH */ + strncpy(s->prompt + challengelen, + memchr(s->prompt, '\n', challengelen) ? + "": "\r\nResponse: ", + (sizeof s->prompt) - challengelen); + s->prompt[(sizeof s->prompt) - 1] = '\0'; + } + } + if (cfg.try_tis_auth && + (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) && + !s->ccard_auth_refused) { + s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE; + logevent("Requested CryptoCard authentication"); + send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END); + crWaitUntil(ispkt); + if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) { + logevent("CryptoCard authentication declined"); + c_write_str(ssh, "CryptoCard authentication refused.\r\n"); + s->ccard_auth_refused = 1; + continue; + } else { + int challengelen = GET_32BIT(ssh->pktin.body); + logevent("Received CryptoCard challenge"); + if (challengelen > sizeof(s->prompt) - 1) + challengelen = sizeof(s->prompt) - 1;/* prevent overrun */ + memcpy(s->prompt, ssh->pktin.body + 4, challengelen); + strncpy(s->prompt + challengelen, + memchr(s->prompt, '\n', challengelen) ? + "" : "\r\nResponse: ", + sizeof(s->prompt) - challengelen); + s->prompt[sizeof(s->prompt) - 1] = '\0'; + } + } + if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) { + sprintf(s->prompt, "%.90s@%.90s's password: ", + s->username, ssh->savedhost); + } + if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) { + char *comment = NULL; + int type; + char msgbuf[256]; + if (flags & FLAG_VERBOSE) + c_write_str(ssh, "Trying public key authentication.\r\n"); + sprintf(msgbuf, "Trying public key \"%.200s\"", cfg.keyfile); + logevent(msgbuf); + type = key_type(cfg.keyfile); + if (type != SSH_KEYTYPE_SSH1) { + sprintf(msgbuf, "Key is of wrong type (%s)", + key_type_to_str(type)); + logevent(msgbuf); + c_write_str(ssh, msgbuf); + c_write_str(ssh, "\r\n"); + s->tried_publickey = 1; + continue; + } + if (!rsakey_encrypted(cfg.keyfile, &comment)) { + if (flags & FLAG_VERBOSE) + c_write_str(ssh, "No passphrase required.\r\n"); + goto tryauth; + } + sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment); + sfree(comment); + } - if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD && !FLAG_WINDOWED) { - char prompt[200]; - sprintf(prompt, "%s@%s's password: ", cfg.username, savedhost); - if (!ssh_get_password(prompt, password, sizeof(password))) { - /* - * get_password failed to get a password (for - * example because one was supplied on the command - * line which has already failed to work). - * Terminate. - */ - logevent("No more passwords to try"); - ssh_state = SSH_STATE_CLOSED; - crReturn(1); - } + /* + * Show password prompt, having first obtained it via a TIS + * or CryptoCard exchange if we're doing TIS or CryptoCard + * authentication. + */ + if (ssh_get_line) { + if (!ssh_get_line(s->prompt, s->password, + sizeof(s->password), TRUE)) { + /* + * get_line failed to get a password (for example + * because one was supplied on the command line + * which has already failed to work). Terminate. + */ + send_packet(ssh, SSH1_MSG_DISCONNECT, + PKT_STR, "No more passwords available to try", + PKT_END); + logevent("Unable to authenticate"); + connection_fatal("Unable to authenticate"); + ssh->state = SSH_STATE_CLOSED; + crReturn(1); + } } else { + /* Prompt may have come from server. We've munged it a bit, so + * we know it to be zero-terminated at least once. */ + int ret; /* need not be saved over crReturn */ + c_write_untrusted(ssh, s->prompt, strlen(s->prompt)); + s->pos = 0; + + setup_userpass_input(ssh, s->password, sizeof(s->password), 0); + do { + crWaitUntil(!ispkt); + ret = process_userpass_input(ssh, in, inlen); + } while (ret == 0); + if (ret < 0) + cleanup_exit(0); + c_write_str(ssh, "\r\n"); + } - if (pktin.type == SSH1_SMSG_FAILURE && - cfg.try_tis_auth && - (supported_auths_mask & (1<pwpkt_type == SSH1_CMSG_AUTH_RSA) { + /* + * Try public key authentication with the specified + * key file. + */ + s->tried_publickey = 1; + + { + int ret = loadrsakey(cfg.keyfile, &s->key, s->password); + if (ret == 0) { + c_write_str(ssh, "Couldn't load private key from "); + c_write_str(ssh, cfg.keyfile); + c_write_str(ssh, ".\r\n"); + continue; /* go and try password */ + } + if (ret == -1) { + c_write_str(ssh, "Wrong passphrase.\r\n"); + s->tried_publickey = 0; + continue; /* try again */ + } + } - pos = 0; - while (pos >= 0) { - crWaitUntil(!ispkt); - while (inlen--) switch (c = *in++) { - case 10: case 13: - password[pos] = 0; - pos = -1; - break; - case 8: case 127: - if (pos > 0) - pos--; - break; - case 21: case 27: - pos = 0; - break; - case 3: case 4: - random_save_seed(); - exit(0); - break; - default: - if (((c >= ' ' && c <= '~') || - ((unsigned char)c >= 160)) && pos < sizeof(password)) - password[pos++] = c; - break; - } - } - c_write("\r\n", 2); - - } - - tryauth: - if (pwpkt_type == SSH1_CMSG_AUTH_RSA) { - /* - * Try public key authentication with the specified - * key file. - */ - static struct RSAKey pubkey; - static Bignum challenge, response; - static int i; - static unsigned char buffer[32]; - - tried_publickey = 1; - i = loadrsakey(cfg.keyfile, &pubkey, password); - if (i == 0) { - c_write("Couldn't load public key from ", 30); - c_write(cfg.keyfile, strlen(cfg.keyfile)); - c_write(".\r\n", 3); - continue; /* go and try password */ - } - if (i == -1) { - c_write("Wrong passphrase.\r\n", 19); - tried_publickey = 0; - continue; /* try again */ - } + /* + * Send a public key attempt. + */ + send_packet(ssh, SSH1_CMSG_AUTH_RSA, + PKT_BIGNUM, s->key.modulus, PKT_END); - /* - * Send a public key attempt. - */ - send_packet(SSH1_CMSG_AUTH_RSA, - PKT_BIGNUM, pubkey.modulus, PKT_END); - - crWaitUntil(ispkt); - if (pktin.type == SSH1_SMSG_FAILURE) { - if (flags & FLAG_VERBOSE) - c_write("Server refused our public key.\r\n", 32); - continue; /* go and try password */ - } - if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) - fatalbox("Bizarre response to offer of public key"); - ssh1_read_bignum(pktin.body, &challenge); - response = rsadecrypt(challenge, &pubkey); - freebn(pubkey.private_exponent); /* burn the evidence */ - - for (i = 0; i < 32; i += 2) { - buffer[i] = response[16-i/2] >> 8; - buffer[i+1] = response[16-i/2] & 0xFF; - } + crWaitUntil(ispkt); + if (ssh->pktin.type == SSH1_SMSG_FAILURE) { + c_write_str(ssh, "Server refused our public key.\r\n"); + continue; /* go and try password */ + } + if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) { + bombout(("Bizarre response to offer of public key")); + crReturn(0); + } - MD5Init(&md5c); - MD5Update(&md5c, buffer, 32); - MD5Update(&md5c, session_id, 16); - MD5Final(buffer, &md5c); - - send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE, - PKT_DATA, buffer, 16, PKT_END); - - crWaitUntil(ispkt); - if (pktin.type == SSH1_SMSG_FAILURE) { - if (flags & FLAG_VERBOSE) - c_write("Failed to authenticate with our public key.\r\n", - 45); - continue; /* go and try password */ - } else if (pktin.type != SSH1_SMSG_SUCCESS) { - fatalbox("Bizarre response to RSA authentication response"); - } + { + int i; + unsigned char buffer[32]; + Bignum challenge, response; - break; /* we're through! */ - } else { - send_packet(pwpkt_type, PKT_STR, password, PKT_END); - } + ssh1_read_bignum(ssh->pktin.body, &challenge); + response = rsadecrypt(challenge, &s->key); + freebn(s->key.private_exponent);/* burn the evidence */ + + for (i = 0; i < 32; i++) { + buffer[i] = bignum_byte(response, 31 - i); + } + + MD5Init(&md5c); + MD5Update(&md5c, buffer, 32); + MD5Update(&md5c, s->session_id, 16); + MD5Final(buffer, &md5c); + + send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE, + PKT_DATA, buffer, 16, PKT_END); + + freebn(challenge); + freebn(response); + } + + crWaitUntil(ispkt); + if (ssh->pktin.type == SSH1_SMSG_FAILURE) { + if (flags & FLAG_VERBOSE) + c_write_str(ssh, "Failed to authenticate with" + " our public key.\r\n"); + continue; /* go and try password */ + } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) { + bombout(("Bizarre response to RSA authentication response")); + crReturn(0); + } + + break; /* we're through! */ + } else { + if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) { + /* + * Defence against traffic analysis: we send a + * whole bunch of packets containing strings of + * different lengths. One of these strings is the + * password, in a SSH1_CMSG_AUTH_PASSWORD packet. + * The others are all random data in + * SSH1_MSG_IGNORE packets. This way a passive + * listener can't tell which is the password, and + * hence can't deduce the password length. + * + * Anybody with a password length greater than 16 + * bytes is going to have enough entropy in their + * password that a listener won't find it _that_ + * much help to know how long it is. So what we'll + * do is: + * + * - if password length < 16, we send 15 packets + * containing string lengths 1 through 15 + * + * - otherwise, we let N be the nearest multiple + * of 8 below the password length, and send 8 + * packets containing string lengths N through + * N+7. This won't obscure the order of + * magnitude of the password length, but it will + * introduce a bit of extra uncertainty. + * + * A few servers (the old 1.2.18 through 1.2.22) + * can't deal with SSH1_MSG_IGNORE. For these + * servers, we need an alternative defence. We make + * use of the fact that the password is interpreted + * as a C string: so we can append a NUL, then some + * random data. + * + * One server (a Cisco one) can deal with neither + * SSH1_MSG_IGNORE _nor_ a padded password string. + * For this server we are left with no defences + * against password length sniffing. + */ + if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) { + /* + * The server can deal with SSH1_MSG_IGNORE, so + * we can use the primary defence. + */ + int bottom, top, pwlen, i; + char *randomstr; + + pwlen = strlen(s->password); + if (pwlen < 16) { + bottom = 0; /* zero length passwords are OK! :-) */ + top = 15; + } else { + bottom = pwlen & ~7; + top = bottom + 7; + } + + assert(pwlen >= bottom && pwlen <= top); + + randomstr = smalloc(top + 1); + + for (i = bottom; i <= top; i++) { + if (i == pwlen) + defer_packet(ssh, s->pwpkt_type, + PKT_STR, s->password, PKT_END); + else { + for (j = 0; j < i; j++) { + do { + randomstr[j] = random_byte(); + } while (randomstr[j] == '\0'); + } + randomstr[i] = '\0'; + defer_packet(ssh, SSH1_MSG_IGNORE, + PKT_STR, randomstr, PKT_END); + } + } + logevent("Sending password with camouflage packets"); + ssh_pkt_defersend(ssh); + } + else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) { + /* + * The server can't deal with SSH1_MSG_IGNORE + * but can deal with padded passwords, so we + * can use the secondary defence. + */ + char string[64]; + char *ss; + int len; + + len = strlen(s->password); + if (len < sizeof(string)) { + ss = string; + strcpy(string, s->password); + len++; /* cover the zero byte */ + while (len < sizeof(string)) { + string[len++] = (char) random_byte(); + } + } else { + ss = s->password; + } + logevent("Sending length-padded password"); + send_packet(ssh, s->pwpkt_type, PKT_INT, len, + PKT_DATA, ss, len, PKT_END); + } else { + /* + * The server has _both_ + * BUG_CHOKES_ON_SSH1_IGNORE and + * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is + * therefore nothing we can do. + */ + int len; + len = strlen(s->password); + logevent("Sending unpadded password"); + send_packet(ssh, s->pwpkt_type, PKT_INT, len, + PKT_DATA, s->password, len, PKT_END); + } + } else { + send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END); + } + } logevent("Sent password"); - memset(password, 0, strlen(password)); + memset(s->password, 0, strlen(s->password)); crWaitUntil(ispkt); - if (pktin.type == SSH1_SMSG_FAILURE) { - if (flags & FLAG_VERBOSE) - c_write("Access denied\r\n", 15); + if (ssh->pktin.type == SSH1_SMSG_FAILURE) { + if (flags & FLAG_VERBOSE) + c_write_str(ssh, "Access denied\r\n"); logevent("Authentication refused"); - } else if (pktin.type == SSH1_MSG_DISCONNECT) { - logevent("Received disconnect request"); - ssh_state = SSH_STATE_CLOSED; - crReturn(1); - } else if (pktin.type != SSH1_SMSG_SUCCESS) { - fatalbox("Strange packet received, type %d", pktin.type); + } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) { + bombout(("Strange packet received, type %d", ssh->pktin.type)); + crReturn(0); } } @@ -1486,68 +2887,635 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) crFinish(1); } -static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { - crBegin; +void sshfwd_close(struct ssh_channel *c) +{ + Ssh ssh = c->ssh; + + if (c && !c->closes) { + /* + * If the channel's remoteid is -1, we have sent + * CHANNEL_OPEN for this channel, but it hasn't even been + * acknowledged by the server. So we must set a close flag + * on it now, and then when the server acks the channel + * open, we can close it then. + */ + if (((int)c->remoteid) != -1) { + if (ssh->version == 1) { + send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, + PKT_END); + } else { + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE); + ssh2_pkt_adduint32(ssh, c->remoteid); + ssh2_pkt_send(ssh); + } + } + c->closes = 1; /* sent MSG_CLOSE */ + if (c->type == CHAN_X11) { + c->u.x11.s = NULL; + logevent("Forwarded X11 connection terminated"); + } else if (c->type == CHAN_SOCKDATA || + c->type == CHAN_SOCKDATA_DORMANT) { + c->u.pfd.s = NULL; + logevent("Forwarded port closed"); + } + } +} + +int sshfwd_write(struct ssh_channel *c, char *buf, int len) +{ + Ssh ssh = c->ssh; + + if (ssh->version == 1) { + send_packet(ssh, SSH1_MSG_CHANNEL_DATA, + PKT_INT, c->remoteid, + PKT_INT, len, PKT_DATA, buf, len, PKT_END); + /* + * In SSH1 we can return 0 here - implying that forwarded + * connections are never individually throttled - because + * the only circumstance that can cause throttling will be + * the whole SSH connection backing up, in which case + * _everything_ will be throttled as a whole. + */ + return 0; + } else { + ssh2_add_channel_data(c, buf, len); + return ssh2_try_send(c); + } +} + +void sshfwd_unthrottle(struct ssh_channel *c, int bufsize) +{ + Ssh ssh = c->ssh; + + if (ssh->version == 1) { + if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) { + c->v.v1.throttling = 0; + ssh1_throttle(ssh, -1); + } + } else { + ssh2_set_window(c, OUR_V2_WINSIZE - bufsize); + } +} + +static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt) +{ + crBegin(ssh->ssh1_protocol_crstate); random_init(); - while (!do_ssh1_login(in, inlen, ispkt)) { + while (!do_ssh1_login(ssh, in, inlen, ispkt)) { + crReturnV; + } + if (ssh->state == SSH_STATE_CLOSED) crReturnV; + + if (cfg.agentfwd && agent_exists()) { + logevent("Requesting agent forwarding"); + send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END); + do { + crReturnV; + } while (!ispkt); + if (ssh->pktin.type != SSH1_SMSG_SUCCESS + && ssh->pktin.type != SSH1_SMSG_FAILURE) { + bombout(("Protocol confusion")); + crReturnV; + } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) { + logevent("Agent forwarding refused"); + } else { + logevent("Agent forwarding enabled"); + ssh->agentfwd_enabled = TRUE; + } + } + + if (cfg.x11_forward) { + char proto[20], data[64]; + logevent("Requesting X11 forwarding"); + x11_invent_auth(proto, sizeof(proto), data, sizeof(data)); + if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) { + send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING, + PKT_STR, proto, PKT_STR, data, + PKT_INT, 0, PKT_END); + } else { + send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING, + PKT_STR, proto, PKT_STR, data, PKT_END); + } + do { + crReturnV; + } while (!ispkt); + if (ssh->pktin.type != SSH1_SMSG_SUCCESS + && ssh->pktin.type != SSH1_SMSG_FAILURE) { + bombout(("Protocol confusion")); + crReturnV; + } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) { + logevent("X11 forwarding refused"); + } else { + logevent("X11 forwarding enabled"); + ssh->X11_fwd_enabled = TRUE; + } + } + + { + char type; + int n; + int sport,dport,sserv,dserv; + char sports[256], dports[256], host[256]; + char buf[1024]; + struct servent *se; + + ssh->rportfwds = newtree234(ssh_rportcmp_ssh1); + /* Add port forwardings. */ + ssh->portfwd_strptr = cfg.portfwd; + while (*ssh->portfwd_strptr) { + type = *ssh->portfwd_strptr++; + n = 0; + while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') + sports[n++] = *ssh->portfwd_strptr++; + sports[n] = 0; + if (*ssh->portfwd_strptr == '\t') + ssh->portfwd_strptr++; + n = 0; + while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') + host[n++] = *ssh->portfwd_strptr++; + host[n] = 0; + if (*ssh->portfwd_strptr == ':') + ssh->portfwd_strptr++; + n = 0; + while (*ssh->portfwd_strptr) + dports[n++] = *ssh->portfwd_strptr++; + dports[n] = 0; + ssh->portfwd_strptr++; + dport = atoi(dports); + dserv = 0; + if (dport == 0) { + dserv = 1; + se = getservbyname(dports, NULL); + if (se != NULL) { + dport = ntohs(se->s_port); + } else { + sprintf(buf, + "Service lookup failed for destination port \"%s\"", + dports); + logevent(buf); + } + } + sport = atoi(sports); + sserv = 0; + if (sport == 0) { + sserv = 1; + se = getservbyname(sports, NULL); + if (se != NULL) { + sport = ntohs(se->s_port); + } else { + sprintf(buf, + "Service lookup failed for source port \"%s\"", + sports); + logevent(buf); + } + } + if (sport && dport) { + if (type == 'L') { + pfd_addforward(host, dport, sport); + sprintf(buf, "Local port %.*s%.*s%d%.*s forwarding to" + " %s:%.*s%.*s%d%.*s", + sserv ? strlen(sports) : 0, sports, + sserv, "(", sport, sserv, ")", + host, + dserv ? strlen(dports) : 0, dports, + dserv, "(", dport, dserv, ")"); + logevent(buf); + } else { + struct ssh_rportfwd *pf; + pf = smalloc(sizeof(*pf)); + strcpy(pf->dhost, host); + pf->dport = dport; + if (add234(ssh->rportfwds, pf) != pf) { + sprintf(buf, + "Duplicate remote port forwarding to %s:%d", + host, dport); + logevent(buf); + sfree(pf); + } else { + sprintf(buf, "Requesting remote port %.*s%.*s%d%.*s" + " forward to %s:%.*s%.*s%d%.*s", + sserv ? strlen(sports) : 0, sports, + sserv, "(", sport, sserv, ")", + host, + dserv ? strlen(dports) : 0, dports, + dserv, "(", dport, dserv, ")"); + logevent(buf); + send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST, + PKT_INT, sport, + PKT_STR, host, + PKT_INT, dport, + PKT_END); + do { + crReturnV; + } while (!ispkt); + if (ssh->pktin.type != SSH1_SMSG_SUCCESS + && ssh->pktin.type != SSH1_SMSG_FAILURE) { + bombout(("Protocol confusion")); + crReturnV; + } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) { + c_write_str(ssh, "Server refused port" + " forwarding\r\n"); + } + logevent("Remote port forwarding enabled"); + } + } + } + } } - if (ssh_state == SSH_STATE_CLOSED) - crReturnV; if (!cfg.nopty) { - send_packet(SSH1_CMSG_REQUEST_PTY, - PKT_STR, cfg.termtype, - PKT_INT, rows, PKT_INT, cols, - PKT_INT, 0, PKT_INT, 0, - PKT_CHAR, 0, - PKT_END); - ssh_state = SSH_STATE_INTERMED; - do { crReturnV; } while (!ispkt); - if (pktin.type != SSH1_SMSG_SUCCESS && pktin.type != SSH1_SMSG_FAILURE) { - fatalbox("Protocol confusion"); - } else if (pktin.type == SSH1_SMSG_FAILURE) { - c_write("Server refused to allocate pty\r\n", 32); - } + send_packet(ssh, SSH1_CMSG_REQUEST_PTY, + PKT_STR, cfg.termtype, + PKT_INT, ssh->term_height, + PKT_INT, ssh->term_width, + PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END); + ssh->state = SSH_STATE_INTERMED; + do { + crReturnV; + } while (!ispkt); + if (ssh->pktin.type != SSH1_SMSG_SUCCESS + && ssh->pktin.type != SSH1_SMSG_FAILURE) { + bombout(("Protocol confusion")); + crReturnV; + } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) { + c_write_str(ssh, "Server refused to allocate pty\r\n"); + ssh->editing = ssh->echoing = 1; + } logevent("Allocated pty"); + } else { + ssh->editing = ssh->echoing = 1; } - if (*cfg.remote_cmd) - send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END); - else - send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END); - logevent("Started session"); + if (cfg.compression) { + send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END); + do { + crReturnV; + } while (!ispkt); + if (ssh->pktin.type != SSH1_SMSG_SUCCESS + && ssh->pktin.type != SSH1_SMSG_FAILURE) { + bombout(("Protocol confusion")); + crReturnV; + } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) { + c_write_str(ssh, "Server refused to compress\r\n"); + } + logevent("Started compression"); + ssh->v1_compressing = TRUE; + zlib_compress_init(); + zlib_decompress_init(); + } - ssh_state = SSH_STATE_SESSION; - if (size_needed) - ssh_size(); + /* + * Start the shell or command. + * + * Special case: if the first-choice command is an SSH2 + * subsystem (hence not usable here) and the second choice + * exists, we fall straight back to that. + */ + { + char *cmd = cfg.remote_cmd_ptr; + + if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) { + cmd = cfg.remote_cmd_ptr2; + ssh->fallback_cmd = TRUE; + } + if (*cmd) + send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END); + else + send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END); + logevent("Started session"); + } + + ssh->state = SSH_STATE_SESSION; + if (ssh->size_needed) + ssh_size(ssh, ssh->term_width, ssh->term_height); + if (ssh->eof_needed) + ssh_special(ssh, TS_EOF); - ssh_send_ok = 1; + ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */ + ssh->send_ok = 1; + ssh->channels = newtree234(ssh_channelcmp); while (1) { crReturnV; if (ispkt) { - if (pktin.type == SSH1_SMSG_STDOUT_DATA || - pktin.type == SSH1_SMSG_STDERR_DATA) { - long len = GET_32BIT(pktin.body); - c_write(pktin.body+4, len); - } else if (pktin.type == SSH1_MSG_DISCONNECT) { - ssh_state = SSH_STATE_CLOSED; + if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA || + ssh->pktin.type == SSH1_SMSG_STDERR_DATA) { + long len = GET_32BIT(ssh->pktin.body); + int bufsize = + from_backend(ssh->frontend, + ssh->pktin.type == SSH1_SMSG_STDERR_DATA, + ssh->pktin.body + 4, len); + if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) { + ssh->v1_stdout_throttling = 1; + ssh1_throttle(ssh, +1); + } + } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) { + ssh->state = SSH_STATE_CLOSED; logevent("Received disconnect request"); - } else if (pktin.type == SSH1_SMSG_SUCCESS) { + crReturnV; + } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) { + /* Remote side is trying to open a channel to talk to our + * X-Server. Give them back a local channel number. */ + struct ssh_channel *c; + + logevent("Received X11 connect request"); + /* Refuse if X11 forwarding is disabled. */ + if (!ssh->X11_fwd_enabled) { + send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END); + logevent("Rejected X11 connect request"); + } else { + c = smalloc(sizeof(struct ssh_channel)); + c->ssh = ssh; + + if (x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL) { + logevent("opening X11 forward connection failed"); + sfree(c); + send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(ssh->pktin.body), + PKT_END); + } else { + logevent + ("opening X11 forward connection succeeded"); + c->remoteid = GET_32BIT(ssh->pktin.body); + c->localid = alloc_channel_id(ssh); + c->closes = 0; + c->v.v1.throttling = 0; + c->type = CHAN_X11; /* identify channel type */ + add234(ssh->channels, c); + send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, + PKT_INT, c->remoteid, PKT_INT, + c->localid, PKT_END); + logevent("Opened X11 forward channel"); + } + } + } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) { + /* Remote side is trying to open a channel to talk to our + * agent. Give them back a local channel number. */ + struct ssh_channel *c; + + /* Refuse if agent forwarding is disabled. */ + if (!ssh->agentfwd_enabled) { + send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END); + } else { + c = smalloc(sizeof(struct ssh_channel)); + c->ssh = ssh; + c->remoteid = GET_32BIT(ssh->pktin.body); + c->localid = alloc_channel_id(ssh); + c->closes = 0; + c->v.v1.throttling = 0; + c->type = CHAN_AGENT; /* identify channel type */ + c->u.a.lensofar = 0; + add234(ssh->channels, c); + send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, + PKT_INT, c->remoteid, PKT_INT, c->localid, + PKT_END); + } + } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) { + /* Remote side is trying to open a channel to talk to a + * forwarded port. Give them back a local channel number. */ + struct ssh_channel *c; + struct ssh_rportfwd pf; + int hostsize, port; + char host[256], buf[1024]; + char *p, *h, *e; + c = smalloc(sizeof(struct ssh_channel)); + c->ssh = ssh; + + hostsize = GET_32BIT(ssh->pktin.body+4); + for(h = host, p = ssh->pktin.body+8; hostsize != 0; hostsize--) { + if (h+1 < host+sizeof(host)) + *h++ = *p; + p++; + } + *h = 0; + port = GET_32BIT(p); + + strcpy(pf.dhost, host); + pf.dport = port; + + if (find234(ssh->rportfwds, &pf, NULL) == NULL) { + sprintf(buf, "Rejected remote port open request for %s:%d", + host, port); + logevent(buf); + send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END); + } else { + sprintf(buf, "Received remote port open request for %s:%d", + host, port); + logevent(buf); + e = pfd_newconnect(&c->u.pfd.s, host, port, c); + if (e != NULL) { + char buf[256]; + sprintf(buf, "Port open failed: %s", e); + logevent(buf); + sfree(c); + send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(ssh->pktin.body), + PKT_END); + } else { + c->remoteid = GET_32BIT(ssh->pktin.body); + c->localid = alloc_channel_id(ssh); + c->closes = 0; + c->v.v1.throttling = 0; + c->type = CHAN_SOCKDATA; /* identify channel type */ + add234(ssh->channels, c); + send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, + PKT_INT, c->remoteid, PKT_INT, + c->localid, PKT_END); + logevent("Forwarded port opened successfully"); + } + } + + } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) { + unsigned int remoteid = GET_32BIT(ssh->pktin.body); + unsigned int localid = GET_32BIT(ssh->pktin.body+4); + struct ssh_channel *c; + + c = find234(ssh->channels, &remoteid, ssh_channelfind); + if (c && c->type == CHAN_SOCKDATA_DORMANT) { + c->remoteid = localid; + c->type = CHAN_SOCKDATA; + c->v.v1.throttling = 0; + pfd_confirm(c->u.pfd.s); + } + + if (c && c->closes) { + /* + * We have a pending close on this channel, + * which we decided on before the server acked + * the channel open. So now we know the + * remoteid, we can close it again. + */ + send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, + PKT_INT, c->remoteid, PKT_END); + } + + } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) { + unsigned int remoteid = GET_32BIT(ssh->pktin.body); + unsigned int localid = GET_32BIT(ssh->pktin.body+4); + struct ssh_channel *c; + + c = find234(ssh->channels, &remoteid, ssh_channelfind); + if (c && c->type == CHAN_SOCKDATA_DORMANT) { + logevent("Forwarded connection refused by server"); + pfd_close(c->u.pfd.s); + del234(ssh->channels, c); + sfree(c); + } + + } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE || + ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) { + /* Remote side closes a channel. */ + unsigned i = GET_32BIT(ssh->pktin.body); + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (c && ((int)c->remoteid) != -1) { + int closetype; + closetype = + (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2); + + if ((c->closes == 0) && (c->type == CHAN_X11)) { + logevent("Forwarded X11 connection terminated"); + assert(c->u.x11.s != NULL); + x11_close(c->u.x11.s); + c->u.x11.s = NULL; + } + if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) { + logevent("Forwarded port closed"); + assert(c->u.pfd.s != NULL); + pfd_close(c->u.pfd.s); + c->u.pfd.s = NULL; + } + + c->closes |= (closetype << 2); /* seen this message */ + if (!(c->closes & closetype)) { + send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid, + PKT_END); + c->closes |= closetype; /* sent it too */ + } + + if (c->closes == 15) { + del234(ssh->channels, c); + sfree(c); + } + } else { + bombout(("Received CHANNEL_CLOSE%s for %s channel %d\n", + ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" : + "_CONFIRMATION", c ? "half-open" : "nonexistent", + i)); + } + } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) { + /* Data sent down one of our channels. */ + int i = GET_32BIT(ssh->pktin.body); + int len = GET_32BIT(ssh->pktin.body + 4); + unsigned char *p = ssh->pktin.body + 8; + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (c) { + int bufsize; + switch (c->type) { + case CHAN_X11: + bufsize = x11_send(c->u.x11.s, p, len); + break; + case CHAN_SOCKDATA: + bufsize = pfd_send(c->u.pfd.s, p, len); + break; + case CHAN_AGENT: + /* Data for an agent message. Buffer it. */ + while (len > 0) { + if (c->u.a.lensofar < 4) { + int l = min(4 - c->u.a.lensofar, len); + memcpy(c->u.a.msglen + c->u.a.lensofar, p, + l); + p += l; + len -= l; + c->u.a.lensofar += l; + } + if (c->u.a.lensofar == 4) { + c->u.a.totallen = + 4 + GET_32BIT(c->u.a.msglen); + c->u.a.message = smalloc(c->u.a.totallen); + memcpy(c->u.a.message, c->u.a.msglen, 4); + } + if (c->u.a.lensofar >= 4 && len > 0) { + int l = + min(c->u.a.totallen - c->u.a.lensofar, + len); + memcpy(c->u.a.message + c->u.a.lensofar, p, + l); + p += l; + len -= l; + c->u.a.lensofar += l; + } + if (c->u.a.lensofar == c->u.a.totallen) { + void *reply, *sentreply; + int replylen; + agent_query(c->u.a.message, + c->u.a.totallen, &reply, + &replylen); + if (reply) + sentreply = reply; + else { + /* Fake SSH_AGENT_FAILURE. */ + sentreply = "\0\0\0\1\5"; + replylen = 5; + } + send_packet(ssh, SSH1_MSG_CHANNEL_DATA, + PKT_INT, c->remoteid, + PKT_INT, replylen, + PKT_DATA, sentreply, replylen, + PKT_END); + if (reply) + sfree(reply); + sfree(c->u.a.message); + c->u.a.lensofar = 0; + } + } + bufsize = 0; /* agent channels never back up */ + break; + } + if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) { + c->v.v1.throttling = 1; + ssh1_throttle(ssh, +1); + } + } + } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) { /* may be from EXEC_SHELL on some servers */ - } else if (pktin.type == SSH1_SMSG_FAILURE) { + } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) { /* may be from EXEC_SHELL on some servers * if no pty is available or in other odd cases. Ignore */ - } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) { - send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END); + } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) { + char buf[100]; + ssh->exitcode = GET_32BIT(ssh->pktin.body); + sprintf(buf, "Server sent command exit status %d", + ssh->exitcode); + logevent(buf); + send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END); + /* + * In case `helpful' firewalls or proxies tack + * extra human-readable text on the end of the + * session which we might mistake for another + * encrypted packet, we close the session once + * we've sent EXIT_CONFIRMATION. + */ + ssh->state = SSH_STATE_CLOSED; + crReturnV; } else { - fatalbox("Strange packet received: type %d", pktin.type); + bombout(("Strange packet received: type %d", ssh->pktin.type)); + crReturnV; } } else { - send_packet(SSH1_CMSG_STDIN_DATA, - PKT_INT, inlen, PKT_DATA, in, inlen, PKT_END); + while (inlen > 0) { + int len = min(inlen, 512); + send_packet(ssh, SSH1_CMSG_STDIN_DATA, + PKT_INT, len, PKT_DATA, in, len, PKT_END); + in += len; + inlen -= len; + } } } @@ -1557,297 +3525,540 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { /* * Utility routine for decoding comma-separated strings in KEXINIT. */ -int in_commasep_string(char *needle, char *haystack, int haylen) { +static int in_commasep_string(char *needle, char *haystack, int haylen) +{ int needlen = strlen(needle); while (1) { - /* - * Is it at the start of the string? - */ - if (haylen >= needlen && /* haystack is long enough */ - !memcmp(needle, haystack, needlen) && /* initial match */ - (haylen == needlen || haystack[needlen] == ',') - /* either , or EOS follows */ - ) - return 1; - /* - * If not, search for the next comma and resume after that. - * If no comma found, terminate. - */ - while (haylen > 0 && *haystack != ',') - haylen--, haystack++; - if (haylen == 0) - return 0; - haylen--, haystack++; /* skip over comma itself */ + /* + * Is it at the start of the string? + */ + if (haylen >= needlen && /* haystack is long enough */ + !memcmp(needle, haystack, needlen) && /* initial match */ + (haylen == needlen || haystack[needlen] == ',') + /* either , or EOS follows */ + ) + return 1; + /* + * If not, search for the next comma and resume after that. + * If no comma found, terminate. + */ + while (haylen > 0 && *haystack != ',') + haylen--, haystack++; + if (haylen == 0) + return 0; + haylen--, haystack++; /* skip over comma itself */ } } /* * SSH2 key creation method. */ -void ssh2_mkkey(Bignum K, char *H, char chr, char *keyspace) { +static void ssh2_mkkey(Ssh ssh, Bignum K, char *H, char *sessid, char chr, + char *keyspace) +{ SHA_State s; /* First 20 bytes. */ SHA_Init(&s); - sha_mpint(&s, K); + if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY)) + sha_mpint(&s, K); SHA_Bytes(&s, H, 20); SHA_Bytes(&s, &chr, 1); - SHA_Bytes(&s, H, 20); + SHA_Bytes(&s, sessid, 20); SHA_Final(&s, keyspace); /* Next 20 bytes. */ SHA_Init(&s); - sha_mpint(&s, K); + if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY)) + sha_mpint(&s, K); SHA_Bytes(&s, H, 20); SHA_Bytes(&s, keyspace, 20); - SHA_Final(&s, keyspace+20); + SHA_Final(&s, keyspace + 20); } /* * Handle the SSH2 transport layer. */ -static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) -{ - static int i, len; - static char *str; - static Bignum e, f, K; - static struct ssh_cipher *cscipher_tobe = NULL; - static struct ssh_cipher *sccipher_tobe = NULL; - static struct ssh_mac *csmac_tobe = NULL; - static struct ssh_mac *scmac_tobe = NULL; - static struct ssh_compress *cscomp_tobe = NULL; - static struct ssh_compress *sccomp_tobe = NULL; - static char *hostkeydata, *sigdata, *keystr; - static int hostkeylen, siglen; - static unsigned char exchange_hash[20]; - static unsigned char keyspace[40]; - - crBegin; +static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt) +{ + struct do_ssh2_transport_state { + int nbits, pbits, warn; + Bignum p, g, e, f, K; + int kex_init_value, kex_reply_value; + const struct ssh_mac **maclist; + int nmacs; + const struct ssh2_cipher *cscipher_tobe; + const struct ssh2_cipher *sccipher_tobe; + const struct ssh_mac *csmac_tobe; + const struct ssh_mac *scmac_tobe; + const struct ssh_compress *cscomp_tobe; + const struct ssh_compress *sccomp_tobe; + char *hostkeydata, *sigdata, *keystr, *fingerprint; + int hostkeylen, siglen; + void *hkey; /* actual host key */ + unsigned char exchange_hash[20]; + int n_preferred_ciphers; + const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX]; + const struct ssh_compress *preferred_comp; + int first_kex; + }; + crState(do_ssh2_transport_state); + + crBegin(ssh->do_ssh2_transport_crstate); + + s->cscipher_tobe = s->sccipher_tobe = NULL; + s->csmac_tobe = s->scmac_tobe = NULL; + s->cscomp_tobe = s->sccomp_tobe = NULL; + random_init(); + s->first_kex = 1; + + { + int i; + /* + * Set up the preferred ciphers. (NULL => warn below here) + */ + s->n_preferred_ciphers = 0; + for (i = 0; i < CIPHER_MAX; i++) { + switch (cfg.ssh_cipherlist[i]) { + case CIPHER_BLOWFISH: + s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish; + break; + case CIPHER_DES: + if (cfg.ssh2_des_cbc) { + s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des; + } + break; + case CIPHER_3DES: + s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des; + break; + case CIPHER_AES: + s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes; + break; + case CIPHER_WARN: + /* Flag for later. Don't bother if it's the last in + * the list. */ + if (i < CIPHER_MAX - 1) { + s->preferred_ciphers[s->n_preferred_ciphers++] = NULL; + } + break; + } + } + } - begin_key_exchange: /* - * Construct and send our key exchange packet. + * Set up preferred compression. */ - ssh2_pkt_init(SSH2_MSG_KEXINIT); - for (i = 0; i < 16; i++) - ssh2_pkt_addbyte((unsigned char)random_byte()); - /* List key exchange algorithms. */ - ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(kex_algs); i++) { - ssh2_pkt_addstring_str(kex_algs[i]->name); - if (i < lenof(kex_algs)-1) - ssh2_pkt_addstring_str(","); - } - /* List server host key algorithms. */ - ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(hostkey_algs); i++) { - ssh2_pkt_addstring_str(hostkey_algs[i]->name); - if (i < lenof(hostkey_algs)-1) - ssh2_pkt_addstring_str(","); - } - /* List client->server encryption algorithms. */ - ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(ciphers); i++) { - ssh2_pkt_addstring_str(ciphers[i]->name); - if (i < lenof(ciphers)-1) - ssh2_pkt_addstring_str(","); - } - /* List server->client encryption algorithms. */ - ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(ciphers); i++) { - ssh2_pkt_addstring_str(ciphers[i]->name); - if (i < lenof(ciphers)-1) - ssh2_pkt_addstring_str(","); - } - /* List client->server MAC algorithms. */ - ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(macs); i++) { - ssh2_pkt_addstring_str(macs[i]->name); - if (i < lenof(macs)-1) - ssh2_pkt_addstring_str(","); - } - /* List server->client MAC algorithms. */ - ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(macs); i++) { - ssh2_pkt_addstring_str(macs[i]->name); - if (i < lenof(macs)-1) - ssh2_pkt_addstring_str(","); - } - /* List client->server compression algorithms. */ - ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(compressions); i++) { - ssh2_pkt_addstring_str(compressions[i]->name); - if (i < lenof(compressions)-1) - ssh2_pkt_addstring_str(","); - } - /* List server->client compression algorithms. */ - ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(compressions); i++) { - ssh2_pkt_addstring_str(compressions[i]->name); - if (i < lenof(compressions)-1) - ssh2_pkt_addstring_str(","); - } - /* List client->server languages. Empty list. */ - ssh2_pkt_addstring_start(); - /* List server->client languages. Empty list. */ - ssh2_pkt_addstring_start(); - /* First KEX packet does _not_ follow, because we're not that brave. */ - ssh2_pkt_addbool(FALSE); - /* Reserved. */ - ssh2_pkt_adduint32(0); - sha_string(&exhash, pktout.data+5, pktout.length-5); - ssh2_pkt_send(); - - if (!ispkt) crWaitUntil(ispkt); - sha_string(&exhash, pktin.data+5, pktin.length-5); + if (cfg.compression) + s->preferred_comp = &ssh_zlib; + else + s->preferred_comp = &ssh_comp_none; + + /* + * Be prepared to work around the buggy MAC problem. + */ + if (ssh->remote_bugs & BUG_SSH2_HMAC) + s->maclist = buggymacs, s->nmacs = lenof(buggymacs); + else + s->maclist = macs, s->nmacs = lenof(macs); + + begin_key_exchange: + { + int i, j, cipherstr_started; + + /* + * Construct and send our key exchange packet. + */ + ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT); + for (i = 0; i < 16; i++) + ssh2_pkt_addbyte(ssh, (unsigned char) random_byte()); + /* List key exchange algorithms. */ + ssh2_pkt_addstring_start(ssh); + for (i = 0; i < lenof(kex_algs); i++) { + if (kex_algs[i] == &ssh_diffiehellman_gex && + (ssh->remote_bugs & BUG_SSH2_DH_GEX)) + continue; + ssh2_pkt_addstring_str(ssh, kex_algs[i]->name); + if (i < lenof(kex_algs) - 1) + ssh2_pkt_addstring_str(ssh, ","); + } + /* List server host key algorithms. */ + ssh2_pkt_addstring_start(ssh); + for (i = 0; i < lenof(hostkey_algs); i++) { + ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name); + if (i < lenof(hostkey_algs) - 1) + ssh2_pkt_addstring_str(ssh, ","); + } + /* List client->server encryption algorithms. */ + ssh2_pkt_addstring_start(ssh); + cipherstr_started = 0; + for (i = 0; i < s->n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = s->preferred_ciphers[i]; + if (!c) continue; /* warning flag */ + for (j = 0; j < c->nciphers; j++) { + if (cipherstr_started) + ssh2_pkt_addstring_str(ssh, ","); + ssh2_pkt_addstring_str(ssh, c->list[j]->name); + cipherstr_started = 1; + } + } + /* List server->client encryption algorithms. */ + ssh2_pkt_addstring_start(ssh); + cipherstr_started = 0; + for (i = 0; i < s->n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = s->preferred_ciphers[i]; + if (!c) continue; /* warning flag */ + for (j = 0; j < c->nciphers; j++) { + if (cipherstr_started) + ssh2_pkt_addstring_str(ssh, ","); + ssh2_pkt_addstring_str(ssh, c->list[j]->name); + cipherstr_started = 1; + } + } + /* List client->server MAC algorithms. */ + ssh2_pkt_addstring_start(ssh); + for (i = 0; i < s->nmacs; i++) { + ssh2_pkt_addstring_str(ssh, s->maclist[i]->name); + if (i < s->nmacs - 1) + ssh2_pkt_addstring_str(ssh, ","); + } + /* List server->client MAC algorithms. */ + ssh2_pkt_addstring_start(ssh); + for (i = 0; i < s->nmacs; i++) { + ssh2_pkt_addstring_str(ssh, s->maclist[i]->name); + if (i < s->nmacs - 1) + ssh2_pkt_addstring_str(ssh, ","); + } + /* List client->server compression algorithms. */ + ssh2_pkt_addstring_start(ssh); + for (i = 0; i < lenof(compressions) + 1; i++) { + const struct ssh_compress *c = + i == 0 ? s->preferred_comp : compressions[i - 1]; + ssh2_pkt_addstring_str(ssh, c->name); + if (i < lenof(compressions)) + ssh2_pkt_addstring_str(ssh, ","); + } + /* List server->client compression algorithms. */ + ssh2_pkt_addstring_start(ssh); + for (i = 0; i < lenof(compressions) + 1; i++) { + const struct ssh_compress *c = + i == 0 ? s->preferred_comp : compressions[i - 1]; + ssh2_pkt_addstring_str(ssh, c->name); + if (i < lenof(compressions)) + ssh2_pkt_addstring_str(ssh, ","); + } + /* List client->server languages. Empty list. */ + ssh2_pkt_addstring_start(ssh); + /* List server->client languages. Empty list. */ + ssh2_pkt_addstring_start(ssh); + /* First KEX packet does _not_ follow, because we're not that brave. */ + ssh2_pkt_addbool(ssh, FALSE); + /* Reserved. */ + ssh2_pkt_adduint32(ssh, 0); + } + + ssh->exhash = ssh->exhashbase; + sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5); + + ssh2_pkt_send(ssh); + + if (!ispkt) + crWaitUntil(ispkt); + sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5); /* * Now examine the other side's KEXINIT to see what we're up * to. */ - if (pktin.type != SSH2_MSG_KEXINIT) { - fatalbox("expected key exchange packet from server"); - } - kex = NULL; hostkey = NULL; cscipher_tobe = NULL; sccipher_tobe = NULL; - csmac_tobe = NULL; scmac_tobe = NULL; cscomp_tobe = NULL; sccomp_tobe = NULL; - pktin.savedpos += 16; /* skip garbage cookie */ - ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */ - for (i = 0; i < lenof(kex_algs); i++) { - if (in_commasep_string(kex_algs[i]->name, str, len)) { - kex = kex_algs[i]; - break; - } - } - ssh2_pkt_getstring(&str, &len); /* host key algorithms */ - for (i = 0; i < lenof(hostkey_algs); i++) { - if (in_commasep_string(hostkey_algs[i]->name, str, len)) { - hostkey = hostkey_algs[i]; - break; - } - } - ssh2_pkt_getstring(&str, &len); /* client->server cipher */ - for (i = 0; i < lenof(ciphers); i++) { - if (in_commasep_string(ciphers[i]->name, str, len)) { - cscipher_tobe = ciphers[i]; - break; - } - } - ssh2_pkt_getstring(&str, &len); /* server->client cipher */ - for (i = 0; i < lenof(ciphers); i++) { - if (in_commasep_string(ciphers[i]->name, str, len)) { - sccipher_tobe = ciphers[i]; - break; - } - } - ssh2_pkt_getstring(&str, &len); /* client->server mac */ - for (i = 0; i < lenof(macs); i++) { - if (in_commasep_string(macs[i]->name, str, len)) { - csmac_tobe = macs[i]; - break; - } - } - ssh2_pkt_getstring(&str, &len); /* server->client mac */ - for (i = 0; i < lenof(macs); i++) { - if (in_commasep_string(macs[i]->name, str, len)) { - scmac_tobe = macs[i]; - break; - } - } - ssh2_pkt_getstring(&str, &len); /* client->server compression */ - for (i = 0; i < lenof(compressions); i++) { - if (in_commasep_string(compressions[i]->name, str, len)) { - cscomp_tobe = compressions[i]; - break; - } + { + char *str; + int i, j, len; + + if (ssh->pktin.type != SSH2_MSG_KEXINIT) { + bombout(("expected key exchange packet from server")); + crReturn(0); + } + ssh->kex = NULL; + ssh->hostkey = NULL; + s->cscipher_tobe = NULL; + s->sccipher_tobe = NULL; + s->csmac_tobe = NULL; + s->scmac_tobe = NULL; + s->cscomp_tobe = NULL; + s->sccomp_tobe = NULL; + ssh->pktin.savedpos += 16; /* skip garbage cookie */ + ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */ + for (i = 0; i < lenof(kex_algs); i++) { + if (kex_algs[i] == &ssh_diffiehellman_gex && + (ssh->remote_bugs & BUG_SSH2_DH_GEX)) + continue; + if (in_commasep_string(kex_algs[i]->name, str, len)) { + ssh->kex = kex_algs[i]; + break; + } + } + ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */ + for (i = 0; i < lenof(hostkey_algs); i++) { + if (in_commasep_string(hostkey_algs[i]->name, str, len)) { + ssh->hostkey = hostkey_algs[i]; + break; + } + } + ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */ + s->warn = 0; + for (i = 0; i < s->n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = s->preferred_ciphers[i]; + if (!c) { + s->warn = 1; + } else { + for (j = 0; j < c->nciphers; j++) { + if (in_commasep_string(c->list[j]->name, str, len)) { + s->cscipher_tobe = c->list[j]; + break; + } + } + } + if (s->cscipher_tobe) { + if (s->warn) + askcipher(s->cscipher_tobe->name, 1); + break; + } + } + if (!s->cscipher_tobe) { + bombout(("Couldn't agree a client-to-server cipher (available: %s)", str)); + crReturn(0); + } + + ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */ + s->warn = 0; + for (i = 0; i < s->n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = s->preferred_ciphers[i]; + if (!c) { + s->warn = 1; + } else { + for (j = 0; j < c->nciphers; j++) { + if (in_commasep_string(c->list[j]->name, str, len)) { + s->sccipher_tobe = c->list[j]; + break; + } + } + } + if (s->sccipher_tobe) { + if (s->warn) + askcipher(s->sccipher_tobe->name, 2); + break; + } + } + if (!s->sccipher_tobe) { + bombout(("Couldn't agree a server-to-client cipher (available: %s)", str)); + crReturn(0); + } + + ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */ + for (i = 0; i < s->nmacs; i++) { + if (in_commasep_string(s->maclist[i]->name, str, len)) { + s->csmac_tobe = s->maclist[i]; + break; + } + } + ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */ + for (i = 0; i < s->nmacs; i++) { + if (in_commasep_string(s->maclist[i]->name, str, len)) { + s->scmac_tobe = s->maclist[i]; + break; + } + } + ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */ + for (i = 0; i < lenof(compressions) + 1; i++) { + const struct ssh_compress *c = + i == 0 ? s->preferred_comp : compressions[i - 1]; + if (in_commasep_string(c->name, str, len)) { + s->cscomp_tobe = c; + break; + } + } + ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */ + for (i = 0; i < lenof(compressions) + 1; i++) { + const struct ssh_compress *c = + i == 0 ? s->preferred_comp : compressions[i - 1]; + if (in_commasep_string(c->name, str, len)) { + s->sccomp_tobe = c; + break; + } + } } - ssh2_pkt_getstring(&str, &len); /* server->client compression */ - for (i = 0; i < lenof(compressions); i++) { - if (in_commasep_string(compressions[i]->name, str, len)) { - sccomp_tobe = compressions[i]; - break; - } + + /* + * Work out the number of bits of key we will need from the key + * exchange. We start with the maximum key length of either + * cipher... + */ + { + int csbits, scbits; + + csbits = s->cscipher_tobe->keylen; + scbits = s->sccipher_tobe->keylen; + s->nbits = (csbits > scbits ? csbits : scbits); } + /* The keys only have 160-bit entropy, since they're based on + * a SHA-1 hash. So cap the key size at 160 bits. */ + if (s->nbits > 160) + s->nbits = 160; /* - * Currently we only support Diffie-Hellman and DSS, so let's - * bomb out if those aren't selected. + * If we're doing Diffie-Hellman group exchange, start by + * requesting a group. */ - if (kex != &ssh_diffiehellman || hostkey != &ssh_dss) - fatalbox("internal fault: chaos in SSH 2 transport layer"); + if (ssh->kex == &ssh_diffiehellman_gex) { + logevent("Doing Diffie-Hellman group exchange"); + ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX; + /* + * Work out how big a DH group we will need to allow that + * much data. + */ + s->pbits = 512 << ((s->nbits - 1) / 64); + ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST); + ssh2_pkt_adduint32(ssh, s->pbits); + ssh2_pkt_send(ssh); + + crWaitUntil(ispkt); + if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) { + bombout(("expected key exchange group packet from server")); + crReturn(0); + } + s->p = ssh2_pkt_getmp(ssh); + s->g = ssh2_pkt_getmp(ssh); + dh_setup_group(s->p, s->g); + s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT; + s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY; + } else { + ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1; + dh_setup_group1(); + s->kex_init_value = SSH2_MSG_KEXDH_INIT; + s->kex_reply_value = SSH2_MSG_KEXDH_REPLY; + } + logevent("Doing Diffie-Hellman key exchange"); /* - * Now we begin the fun. Generate and send e for Diffie-Hellman. + * Now generate and send e for Diffie-Hellman. */ - e = dh_create_e(); - ssh2_pkt_init(SSH2_MSG_KEXDH_INIT); - ssh2_pkt_addmp(e); - ssh2_pkt_send(); + s->e = dh_create_e(s->nbits * 2); + ssh2_pkt_init(ssh, s->kex_init_value); + ssh2_pkt_addmp(ssh, s->e); + ssh2_pkt_send(ssh); crWaitUntil(ispkt); - if (pktin.type != SSH2_MSG_KEXDH_REPLY) { - fatalbox("expected key exchange packet from server"); + if (ssh->pktin.type != s->kex_reply_value) { + bombout(("expected key exchange reply packet from server")); + crReturn(0); } - ssh2_pkt_getstring(&hostkeydata, &hostkeylen); - f = ssh2_pkt_getmp(); - ssh2_pkt_getstring(&sigdata, &siglen); + ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen); + s->f = ssh2_pkt_getmp(ssh); + ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen); - K = dh_find_K(f); + s->K = dh_find_K(s->f); - sha_string(&exhash, hostkeydata, hostkeylen); - sha_mpint(&exhash, e); - sha_mpint(&exhash, f); - sha_mpint(&exhash, K); - SHA_Final(&exhash, exchange_hash); + sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen); + if (ssh->kex == &ssh_diffiehellman_gex) { + sha_uint32(&ssh->exhash, s->pbits); + sha_mpint(&ssh->exhash, s->p); + sha_mpint(&ssh->exhash, s->g); + } + sha_mpint(&ssh->exhash, s->e); + sha_mpint(&ssh->exhash, s->f); + sha_mpint(&ssh->exhash, s->K); + SHA_Final(&ssh->exhash, s->exchange_hash); + + dh_cleanup(); #if 0 - debug(("Exchange hash is:\r\n")); - for (i = 0; i < 20; i++) - debug((" %02x", exchange_hash[i])); - debug(("\r\n")); + debug(("Exchange hash is:\n")); + dmemdump(s->exchange_hash, 20); #endif - hostkey->setkey(hostkeydata, hostkeylen); - if (!hostkey->verifysig(sigdata, siglen, exchange_hash, 20)) - fatalbox("Server failed host key check"); - - /* - * Expect SSH2_MSG_NEWKEYS from server. - */ - crWaitUntil(ispkt); - if (pktin.type != SSH2_MSG_NEWKEYS) - fatalbox("expected new-keys packet from server"); + s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen); + if (!s->hkey || + !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen, + s->exchange_hash, 20)) { + bombout(("Server's host key did not match the signature supplied")); + crReturn(0); + } /* * Authenticate remote host: verify host key. (We've already * checked the signature of the exchange hash.) */ - keystr = hostkey->fmtkey(); - verify_ssh_host_key(savedhost, keystr); - free(keystr); + s->keystr = ssh->hostkey->fmtkey(s->hkey); + s->fingerprint = ssh->hostkey->fingerprint(s->hkey); + verify_ssh_host_key(ssh->savedhost, ssh->savedport, ssh->hostkey->keytype, + s->keystr, s->fingerprint); + if (s->first_kex) { /* don't bother logging this in rekeys */ + logevent("Host key fingerprint is:"); + logevent(s->fingerprint); + } + sfree(s->fingerprint); + sfree(s->keystr); + ssh->hostkey->freekey(s->hkey); /* * Send SSH2_MSG_NEWKEYS. */ - ssh2_pkt_init(SSH2_MSG_NEWKEYS); - ssh2_pkt_send(); + ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS); + ssh2_pkt_send(ssh); + + /* + * Expect SSH2_MSG_NEWKEYS from server. + */ + crWaitUntil(ispkt); + if (ssh->pktin.type != SSH2_MSG_NEWKEYS) { + bombout(("expected new-keys packet from server")); + crReturn(0); + } /* * Create and initialise session keys. */ - cscipher = cscipher_tobe; - sccipher = sccipher_tobe; - csmac = csmac_tobe; - scmac = scmac_tobe; - cscomp = cscomp_tobe; - sccomp = sccomp_tobe; + ssh->cscipher = s->cscipher_tobe; + ssh->sccipher = s->sccipher_tobe; + ssh->csmac = s->csmac_tobe; + ssh->scmac = s->scmac_tobe; + ssh->cscomp = s->cscomp_tobe; + ssh->sccomp = s->sccomp_tobe; + ssh->cscomp->compress_init(); + ssh->sccomp->decompress_init(); + /* + * Set IVs after keys. Here we use the exchange hash from the + * _first_ key exchange. + */ + { + unsigned char keyspace[40]; + if (s->first_kex) + memcpy(ssh->v2_session_id, s->exchange_hash, + sizeof(s->exchange_hash)); + ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace); + ssh->cscipher->setcskey(keyspace); + ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace); + ssh->sccipher->setsckey(keyspace); + ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace); + ssh->cscipher->setcsiv(keyspace); + ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace); + ssh->sccipher->setsciv(keyspace); + ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace); + ssh->csmac->setcskey(keyspace); + ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace); + ssh->scmac->setsckey(keyspace); + } + /* - * Set IVs after keys. + * If this is the first key exchange phase, we must pass the + * SSH2_MSG_NEWKEYS packet to the next layer, not because it + * wants to see it but because it will need time to initialise + * itself before it sees an actual packet. In subsequent key + * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because + * it would only confuse the layer above. */ - ssh2_mkkey(K, exchange_hash, 'C', keyspace); cscipher->setcskey(keyspace); - ssh2_mkkey(K, exchange_hash, 'D', keyspace); cscipher->setsckey(keyspace); - ssh2_mkkey(K, exchange_hash, 'A', keyspace); cscipher->setcsiv(keyspace); - ssh2_mkkey(K, exchange_hash, 'B', keyspace); sccipher->setsciv(keyspace); - ssh2_mkkey(K, exchange_hash, 'E', keyspace); csmac->setcskey(keyspace); - ssh2_mkkey(K, exchange_hash, 'F', keyspace); scmac->setsckey(keyspace); + if (!s->first_kex) { + crReturn(0); + } + s->first_kex = 0; /* * Now we're encrypting. Begin returning 1 to the protocol main @@ -1855,160 +4066,865 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) * transport. If we ever see a KEXINIT, we must go back to the * start. */ - do { - crReturn(1); - } while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)); + while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) { + crReturn(1); + } + logevent("Server initiated key re-exchange"); goto begin_key_exchange; crFinish(1); } /* - * SSH2: remote identifier for the main session channel. + * Add data to an SSH2 channel output buffer. */ -static unsigned long ssh_remote_channel; +static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, + int len) +{ + bufchain_add(&c->v.v2.outbuffer, buf, len); +} + +/* + * Attempt to send data on an SSH2 channel. + */ +static int ssh2_try_send(struct ssh_channel *c) +{ + Ssh ssh = c->ssh; + + while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) { + int len; + void *data; + bufchain_prefix(&c->v.v2.outbuffer, &data, &len); + if ((unsigned)len > c->v.v2.remwindow) + len = c->v.v2.remwindow; + if ((unsigned)len > c->v.v2.remmaxpkt) + len = c->v.v2.remmaxpkt; + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA); + ssh2_pkt_adduint32(ssh, c->remoteid); + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, data, len); + ssh2_pkt_send(ssh); + bufchain_consume(&c->v.v2.outbuffer, len); + c->v.v2.remwindow -= len; + } + + /* + * After having sent as much data as we can, return the amount + * still buffered. + */ + return bufchain_size(&c->v.v2.outbuffer); +} + +/* + * Potentially enlarge the window on an SSH2 channel. + */ +static void ssh2_set_window(struct ssh_channel *c, unsigned newwin) +{ + Ssh ssh = c->ssh; + + /* + * Never send WINDOW_ADJUST for a channel that the remote side + * already thinks it's closed; there's no point, since it won't + * be sending any more data anyway. + */ + if (c->closes != 0) + return; + + if (newwin > c->v.v2.locwindow) { + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST); + ssh2_pkt_adduint32(ssh, c->remoteid); + ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow); + ssh2_pkt_send(ssh); + c->v.v2.locwindow = newwin; + } +} /* * Handle the SSH2 userauth and connection layers. */ -static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) +static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt) { - static unsigned long remote_winsize; - static unsigned long remote_maxpkt; + struct do_ssh2_authconn_state { + enum { + AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE, + AUTH_PASSWORD, + AUTH_KEYBOARD_INTERACTIVE + } method; + enum { + AUTH_TYPE_NONE, + AUTH_TYPE_PUBLICKEY, + AUTH_TYPE_PUBLICKEY_OFFER_LOUD, + AUTH_TYPE_PUBLICKEY_OFFER_QUIET, + AUTH_TYPE_PASSWORD, + AUTH_TYPE_KEYBOARD_INTERACTIVE, + AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET + } type; + int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter; + int tried_pubkey_config, tried_agent, tried_keyb_inter; + int kbd_inter_running; + int we_are_in; + int num_prompts, curr_prompt, echo; + char username[100]; + int got_username; + char pwprompt[200]; + char password[100]; + void *publickey_blob; + int publickey_bloblen; + unsigned char request[5], *response, *p; + int responselen; + int keyi, nkeys; + int authed; + char *pkblob, *alg, *commentp; + int pklen, alglen, commentlen; + int siglen, retlen, len; + char *q, *agentreq, *ret; + int try_send; + }; + crState(do_ssh2_authconn_state); + + crBegin(ssh->do_ssh2_authconn_crstate); + + /* + * Request userauth protocol, and await a response to it. + */ + ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST); + ssh2_pkt_addstring(ssh, "ssh-userauth"); + ssh2_pkt_send(ssh); + crWaitUntilV(ispkt); + if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) { + bombout(("Server refused user authentication protocol")); + crReturnV; + } + + /* + * We repeat this whole loop, including the username prompt, + * until we manage a successful authentication. If the user + * types the wrong _password_, they can be sent back to the + * beginning to try another username, if this is configured on. + * (If they specify a username in the config, they are never + * asked, even if they do give a wrong password.) + * + * I think this best serves the needs of + * + * - the people who have no configuration, no keys, and just + * want to try repeated (username,password) pairs until they + * type both correctly + * + * - people who have keys and configuration but occasionally + * need to fall back to passwords + * + * - people with a key held in Pageant, who might not have + * logged in to a particular machine before; so they want to + * type a username, and then _either_ their key will be + * accepted, _or_ they will type a password. If they mistype + * the username they will want to be able to get back and + * retype it! + */ + s->username[0] = '\0'; + s->got_username = FALSE; + do { + /* + * Get a username. + */ + if (s->got_username && !cfg.change_username) { + /* + * We got a username last time round this loop, and + * with change_username turned off we don't try to get + * it again. + */ + } else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { + if (ssh_get_line && !ssh_getline_pw_only) { + if (!ssh_get_line("login as: ", + s->username, sizeof(s->username), FALSE)) { + /* + * get_line failed to get a username. + * Terminate. + */ + logevent("No username provided. Abandoning session."); + ssh->state = SSH_STATE_CLOSED; + crReturnV; + } + } else { + int ret; /* need not be saved across crReturn */ + c_write_str(ssh, "login as: "); + ssh->send_ok = 1; + setup_userpass_input(ssh, s->username, sizeof(s->username), 1); + do { + crWaitUntilV(!ispkt); + ret = process_userpass_input(ssh, in, inlen); + } while (ret == 0); + if (ret < 0) + cleanup_exit(0); + } + c_write_str(ssh, "\r\n"); + s->username[strcspn(s->username, "\n\r")] = '\0'; + } else { + char stuff[200]; + strncpy(s->username, cfg.username, sizeof(s->username)); + s->username[sizeof(s->username)-1] = '\0'; + if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) { + sprintf(stuff, "Using username \"%s\".\r\n", s->username); + c_write_str(ssh, stuff); + } + } + s->got_username = TRUE; + + /* + * Send an authentication request using method "none": (a) + * just in case it succeeds, and (b) so that we know what + * authentication methods we can usefully try next. + */ + ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + + ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(ssh, s->username); + ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */ + ssh2_pkt_addstring(ssh, "none"); /* method */ + ssh2_pkt_send(ssh); + s->type = AUTH_TYPE_NONE; + s->gotit = FALSE; + s->we_are_in = FALSE; + + s->tried_pubkey_config = FALSE; + s->tried_agent = FALSE; + s->tried_keyb_inter = FALSE; + s->kbd_inter_running = FALSE; + /* Load the pub half of cfg.keyfile so we notice if it's in Pageant */ + if (*cfg.keyfile) { + int keytype; + logeventf("Reading private key file \"%.150s\"", cfg.keyfile); + keytype = key_type(cfg.keyfile); + if (keytype == SSH_KEYTYPE_SSH2) { + s->publickey_blob = + ssh2_userkey_loadpub(cfg.keyfile, NULL, + &s->publickey_bloblen); + } else { + char msgbuf[256]; + logeventf("Unable to use this key file (%s)", + key_type_to_str(keytype)); + sprintf(msgbuf, "Unable to use key file \"%.150s\" (%s)\r\n", + cfg.keyfile, key_type_to_str(keytype)); + c_write_str(ssh, msgbuf); + s->publickey_blob = NULL; + } + } else + s->publickey_blob = NULL; + + while (1) { + /* + * Wait for the result of the last authentication request. + */ + if (!s->gotit) + crWaitUntilV(ispkt); + while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) { + char *banner; + int size; + /* + * Don't show the banner if we're operating in + * non-verbose non-interactive mode. (It's probably + * a script, which means nobody will read the + * banner _anyway_, and moreover the printing of + * the banner will screw up processing on the + * output of (say) plink.) + */ + if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) { + ssh2_pkt_getstring(ssh, &banner, &size); + if (banner) + c_write_untrusted(ssh, banner, size); + } + crWaitUntilV(ispkt); + } + if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) { + logevent("Access granted"); + s->we_are_in = TRUE; + break; + } + + if (s->kbd_inter_running && + ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) { + /* + * This is either a further set-of-prompts packet + * in keyboard-interactive authentication, or it's + * the same one and we came back here with `gotit' + * set. In the former case, we must reset the + * curr_prompt variable. + */ + if (!s->gotit) + s->curr_prompt = 0; + } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) { + bombout(("Strange packet received during authentication: type %d", + ssh->pktin.type)); + crReturnV; + } - crBegin; + s->gotit = FALSE; + + /* + * OK, we're now sitting on a USERAUTH_FAILURE message, so + * we can look at the string in it and know what we can + * helpfully try next. + */ + if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) { + char *methods; + int methlen; + ssh2_pkt_getstring(ssh, &methods, &methlen); + s->kbd_inter_running = FALSE; + if (!ssh2_pkt_getbool(ssh)) { + /* + * We have received an unequivocal Access + * Denied. This can translate to a variety of + * messages: + * + * - if we'd just tried "none" authentication, + * it's not worth printing anything at all + * + * - if we'd just tried a public key _offer_, + * the message should be "Server refused our + * key" (or no message at all if the key + * came from Pageant) + * + * - if we'd just tried anything else, the + * message really should be "Access denied". + * + * Additionally, if we'd just tried password + * authentication, we should break out of this + * whole loop so as to go back to the username + * prompt. + */ + if (s->type == AUTH_TYPE_NONE) { + /* do nothing */ + } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD || + s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) { + if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD) + c_write_str(ssh, "Server refused our key\r\n"); + logevent("Server refused public key"); + } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) { + /* server declined keyboard-interactive; ignore */ + } else { + c_write_str(ssh, "Access denied\r\n"); + logevent("Access denied"); + if (s->type == AUTH_TYPE_PASSWORD) { + s->we_are_in = FALSE; + break; + } + } + } else { + c_write_str(ssh, "Further authentication required\r\n"); + logevent("Further authentication required"); + } - /* - * Request userauth protocol, and await a response to it. - */ - ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST); - ssh2_pkt_addstring("ssh-userauth"); - ssh2_pkt_send(); - crWaitUntilV(ispkt); - if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) - fatalbox("Server refused user authentication protocol"); + s->can_pubkey = + in_commasep_string("publickey", methods, methlen); + s->can_passwd = + in_commasep_string("password", methods, methlen); + s->can_keyb_inter = cfg.try_ki_auth && + in_commasep_string("keyboard-interactive", methods, methlen); + } - /* - * FIXME: currently we support only password authentication. - * (This places us technically in violation of the SSH2 spec. - * We must fix this.) - */ - while (1) { - /* - * Get a username and a password. - */ - static char username[100]; - static char password[100]; - static int pos = 0; - static char c; - - if ((flags & FLAG_CONNECTION) && !*cfg.username) { - c_write("login as: ", 10); - while (pos >= 0) { - crWaitUntilV(!ispkt); - while (inlen--) switch (c = *in++) { - case 10: case 13: - username[pos] = 0; - pos = -1; - break; - case 8: case 127: - if (pos > 0) { - c_write("\b \b", 3); - pos--; + s->method = 0; + ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + + /* + * Most password/passphrase prompts will be + * non-echoing, so we set this to 0 by default. + * Exception is that some keyboard-interactive prompts + * can be echoing, in which case we'll set this to 1. + */ + s->echo = 0; + + if (!s->method && s->can_pubkey && + agent_exists() && !s->tried_agent) { + /* + * Attempt public-key authentication using Pageant. + */ + void *r; + s->authed = FALSE; + + ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY; + + s->tried_agent = TRUE; + + logevent("Pageant is running. Requesting keys."); + + /* Request the keys held by the agent. */ + PUT_32BIT(s->request, 1); + s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES; + agent_query(s->request, 5, &r, &s->responselen); + s->response = (unsigned char *) r; + if (s->response && s->responselen >= 5 && + s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) { + s->p = s->response + 5; + s->nkeys = GET_32BIT(s->p); + s->p += 4; + { + char buf[64]; + sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys); + logevent(buf); } - break; - case 21: case 27: - while (pos > 0) { - c_write("\b \b", 3); - pos--; + for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) { + void *vret; + + { + char buf[64]; + sprintf(buf, "Trying Pageant key #%d", s->keyi); + logevent(buf); + } + s->pklen = GET_32BIT(s->p); + s->p += 4; + if (s->publickey_blob && + s->pklen == s->publickey_bloblen && + !memcmp(s->p, s->publickey_blob, + s->publickey_bloblen)) { + logevent("This key matches configured key file"); + s->tried_pubkey_config = 1; + } + s->pkblob = s->p; + s->p += s->pklen; + s->alglen = GET_32BIT(s->pkblob); + s->alg = s->pkblob + 4; + s->commentlen = GET_32BIT(s->p); + s->p += 4; + s->commentp = s->p; + s->p += s->commentlen; + ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(ssh, s->username); + ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */ + ssh2_pkt_addstring(ssh, "publickey"); /* method */ + ssh2_pkt_addbool(ssh, FALSE); /* no signature included */ + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, s->alg, s->alglen); + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen); + ssh2_pkt_send(ssh); + + crWaitUntilV(ispkt); + if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) { + logevent("Key refused"); + continue; + } + + if (flags & FLAG_VERBOSE) { + c_write_str(ssh, "Authenticating with " + "public key \""); + c_write(ssh, s->commentp, s->commentlen); + c_write_str(ssh, "\" from agent\r\n"); + } + + /* + * Server is willing to accept the key. + * Construct a SIGN_REQUEST. + */ + ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(ssh, s->username); + ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */ + ssh2_pkt_addstring(ssh, "publickey"); /* method */ + ssh2_pkt_addbool(ssh, TRUE); + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, s->alg, s->alglen); + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen); + + s->siglen = ssh->pktout.length - 5 + 4 + 20; + s->len = 1; /* message type */ + s->len += 4 + s->pklen; /* key blob */ + s->len += 4 + s->siglen; /* data to sign */ + s->len += 4; /* flags */ + s->agentreq = smalloc(4 + s->len); + PUT_32BIT(s->agentreq, s->len); + s->q = s->agentreq + 4; + *s->q++ = SSH2_AGENTC_SIGN_REQUEST; + PUT_32BIT(s->q, s->pklen); + s->q += 4; + memcpy(s->q, s->pkblob, s->pklen); + s->q += s->pklen; + PUT_32BIT(s->q, s->siglen); + s->q += 4; + /* Now the data to be signed... */ + PUT_32BIT(s->q, 20); + s->q += 4; + memcpy(s->q, ssh->v2_session_id, 20); + s->q += 20; + memcpy(s->q, ssh->pktout.data + 5, + ssh->pktout.length - 5); + s->q += ssh->pktout.length - 5; + /* And finally the (zero) flags word. */ + PUT_32BIT(s->q, 0); + agent_query(s->agentreq, s->len + 4, &vret, &s->retlen); + s->ret = vret; + sfree(s->agentreq); + if (s->ret) { + if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) { + logevent("Sending Pageant's response"); + ssh2_add_sigblob(ssh, s->pkblob, s->pklen, + s->ret + 9, + GET_32BIT(s->ret + 5)); + ssh2_pkt_send(ssh); + s->authed = TRUE; + break; + } else { + logevent + ("Pageant failed to answer challenge"); + sfree(s->ret); + } + } } - break; - case 3: case 4: - random_save_seed(); - exit(0); - break; - default: - if (((c >= ' ' && c <= '~') || - ((unsigned char)c >= 160)) && pos < 40) { - username[pos++] = c; - c_write(&c, 1); + if (s->authed) + continue; + } + } + + if (!s->method && s->can_pubkey && s->publickey_blob + && !s->tried_pubkey_config) { + unsigned char *pub_blob; + char *algorithm, *comment; + int pub_blob_len; + + s->tried_pubkey_config = TRUE; + + ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY; + + /* + * Try the public key supplied in the configuration. + * + * First, offer the public blob to see if the server is + * willing to accept it. + */ + pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm, + &pub_blob_len); + if (pub_blob) { + ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(ssh, s->username); + ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */ + ssh2_pkt_addstring(ssh, "publickey"); /* method */ + ssh2_pkt_addbool(ssh, FALSE); /* no signature included */ + ssh2_pkt_addstring(ssh, algorithm); + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, pub_blob, pub_blob_len); + ssh2_pkt_send(ssh); + logevent("Offered public key"); /* FIXME */ + + crWaitUntilV(ispkt); + if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) { + s->gotit = TRUE; + s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD; + continue; /* key refused; give up on it */ } - break; + + logevent("Offer of public key accepted"); + /* + * Actually attempt a serious authentication using + * the key. + */ + if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) { + sprintf(s->pwprompt, + "Passphrase for key \"%.100s\": ", + comment); + s->need_pw = TRUE; + } else { + s->need_pw = FALSE; + } + c_write_str(ssh, "Authenticating with public key \""); + c_write_str(ssh, comment); + c_write_str(ssh, "\"\r\n"); + s->method = AUTH_PUBLICKEY_FILE; } } - c_write("\r\n", 2); - username[strcspn(username, "\n\r")] = '\0'; - } else { - char stuff[200]; - strncpy(username, cfg.username, 99); - username[99] = '\0'; - if (flags & FLAG_VERBOSE) { - sprintf(stuff, "Using username \"%s\".\r\n", username); - c_write(stuff, strlen(stuff)); + + if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) { + s->method = AUTH_KEYBOARD_INTERACTIVE; + s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE; + s->tried_keyb_inter = TRUE; + + ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER; + + ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(ssh, s->username); + ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */ + ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */ + ssh2_pkt_addstring(ssh, ""); /* lang */ + ssh2_pkt_addstring(ssh, ""); + ssh2_pkt_send(ssh); + + crWaitUntilV(ispkt); + if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) { + if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) + s->gotit = TRUE; + logevent("Keyboard-interactive authentication refused"); + s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET; + continue; + } + + s->kbd_inter_running = TRUE; + s->curr_prompt = 0; } - } - if (!(flags & FLAG_WINDOWED)) { - char prompt[200]; - sprintf(prompt, "%s@%s's password: ", cfg.username, savedhost); - if (!ssh_get_password(prompt, password, sizeof(password))) { - /* - * get_password failed to get a password (for - * example because one was supplied on the command - * line which has already failed to work). - * Terminate. - */ - logevent("No more passwords to try"); - ssh_state = SSH_STATE_CLOSED; - crReturnV; - } - } else { - c_write("password: ", 10); - - pos = 0; - while (pos >= 0) { - crWaitUntilV(!ispkt); - while (inlen--) switch (c = *in++) { - case 10: case 13: - password[pos] = 0; - pos = -1; - break; - case 8: case 127: - if (pos > 0) - pos--; - break; - case 21: case 27: - pos = 0; - break; - case 3: case 4: - random_save_seed(); - exit(0); - break; - default: - if (((c >= ' ' && c <= '~') || - ((unsigned char)c >= 160)) && pos < 40) - password[pos++] = c; - break; - } - } - c_write("\r\n", 2); - } + if (s->kbd_inter_running) { + s->method = AUTH_KEYBOARD_INTERACTIVE; + s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE; + s->tried_keyb_inter = TRUE; + + ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER; + + if (s->curr_prompt == 0) { + /* + * We've got a fresh USERAUTH_INFO_REQUEST. + * Display header data, and start going through + * the prompts. + */ + char *name, *inst, *lang; + int name_len, inst_len, lang_len; + + ssh2_pkt_getstring(ssh, &name, &name_len); + ssh2_pkt_getstring(ssh, &inst, &inst_len); + ssh2_pkt_getstring(ssh, &lang, &lang_len); + if (name_len > 0) { + c_write_untrusted(ssh, name, name_len); + c_write_str(ssh, "\r\n"); + } + if (inst_len > 0) { + c_write_untrusted(ssh, inst, inst_len); + c_write_str(ssh, "\r\n"); + } + s->num_prompts = ssh2_pkt_getuint32(ssh); + } + + /* + * If there are prompts remaining in the packet, + * display one and get a response. + */ + if (s->curr_prompt < s->num_prompts) { + char *prompt; + int prompt_len; + + ssh2_pkt_getstring(ssh, &prompt, &prompt_len); + if (prompt_len > 0) { + strncpy(s->pwprompt, prompt, sizeof(s->pwprompt)); + s->pwprompt[prompt_len < sizeof(s->pwprompt) ? + prompt_len : sizeof(s->pwprompt)-1] = '\0'; + } else { + strcpy(s->pwprompt, + ": "); + } + s->echo = ssh2_pkt_getbool(ssh); + s->need_pw = TRUE; + } else + s->need_pw = FALSE; + } - ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); - ssh2_pkt_addstring(username); - ssh2_pkt_addstring("ssh-connection"); /* service requested */ - ssh2_pkt_addstring("password"); - ssh2_pkt_addbool(FALSE); - ssh2_pkt_addstring(password); - ssh2_pkt_send(); + if (!s->method && s->can_passwd) { + s->method = AUTH_PASSWORD; + ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD; + sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username, + ssh->savedhost); + s->need_pw = TRUE; + } - crWaitUntilV(ispkt); - if (pktin.type != SSH2_MSG_USERAUTH_SUCCESS) { - c_write("Access denied\r\n", 15); - logevent("Authentication refused"); - } else - break; - } + if (s->need_pw) { + if (ssh_get_line) { + if (!ssh_get_line(s->pwprompt, s->password, + sizeof(s->password), TRUE)) { + /* + * get_line failed to get a password (for + * example because one was supplied on the + * command line which has already failed to + * work). Terminate. + */ + ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT); + ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION); + ssh2_pkt_addstring(ssh, "No more passwords available" + " to try"); + ssh2_pkt_addstring(ssh, "en"); /* language tag */ + ssh2_pkt_send(ssh); + logevent("Unable to authenticate"); + connection_fatal("Unable to authenticate"); + ssh->state = SSH_STATE_CLOSED; + crReturnV; + } + } else { + int ret; /* need not be saved across crReturn */ + c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt)); + ssh->send_ok = 1; + + setup_userpass_input(ssh, s->password, + sizeof(s->password), s->echo); + do { + crWaitUntilV(!ispkt); + ret = process_userpass_input(ssh, in, inlen); + } while (ret == 0); + if (ret < 0) + cleanup_exit(0); + c_write_str(ssh, "\r\n"); + } + } + + if (s->method == AUTH_PUBLICKEY_FILE) { + /* + * We have our passphrase. Now try the actual authentication. + */ + struct ssh2_userkey *key; + + key = ssh2_load_userkey(cfg.keyfile, s->password); + if (key == SSH2_WRONG_PASSPHRASE || key == NULL) { + if (key == SSH2_WRONG_PASSPHRASE) { + c_write_str(ssh, "Wrong passphrase\r\n"); + s->tried_pubkey_config = FALSE; + } else { + c_write_str(ssh, "Unable to load private key\r\n"); + s->tried_pubkey_config = TRUE; + } + /* Send a spurious AUTH_NONE to return to the top. */ + ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(ssh, s->username); + ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */ + ssh2_pkt_addstring(ssh, "none"); /* method */ + ssh2_pkt_send(ssh); + s->type = AUTH_TYPE_NONE; + } else { + unsigned char *pkblob, *sigblob, *sigdata; + int pkblob_len, sigblob_len, sigdata_len; + + /* + * We have loaded the private key and the server + * has announced that it's willing to accept it. + * Hallelujah. Generate a signature and send it. + */ + ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(ssh, s->username); + ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */ + ssh2_pkt_addstring(ssh, "publickey"); /* method */ + ssh2_pkt_addbool(ssh, TRUE); + ssh2_pkt_addstring(ssh, key->alg->name); + pkblob = key->alg->public_blob(key->data, &pkblob_len); + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, pkblob, pkblob_len); + + /* + * The data to be signed is: + * + * string session-id + * + * followed by everything so far placed in the + * outgoing packet. + */ + sigdata_len = ssh->pktout.length - 5 + 4 + 20; + sigdata = smalloc(sigdata_len); + PUT_32BIT(sigdata, 20); + memcpy(sigdata + 4, ssh->v2_session_id, 20); + memcpy(sigdata + 24, ssh->pktout.data + 5, + ssh->pktout.length - 5); + sigblob = key->alg->sign(key->data, sigdata, + sigdata_len, &sigblob_len); + ssh2_add_sigblob(ssh, pkblob, pkblob_len, + sigblob, sigblob_len); + sfree(pkblob); + sfree(sigblob); + sfree(sigdata); + + ssh2_pkt_send(ssh); + s->type = AUTH_TYPE_PUBLICKEY; + } + } else if (s->method == AUTH_PASSWORD) { + /* + * We send the password packet lumped tightly together with + * an SSH_MSG_IGNORE packet. The IGNORE packet contains a + * string long enough to make the total length of the two + * packets constant. This should ensure that a passive + * listener doing traffic analyis can't work out the length + * of the password. + * + * For this to work, we need an assumption about the + * maximum length of the password packet. I think 256 is + * pretty conservative. Anyone using a password longer than + * that probably doesn't have much to worry about from + * people who find out how long their password is! + */ + ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(ssh, s->username); + ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */ + ssh2_pkt_addstring(ssh, "password"); + ssh2_pkt_addbool(ssh, FALSE); + ssh2_pkt_addstring(ssh, s->password); + ssh2_pkt_defer(ssh); + /* + * We'll include a string that's an exact multiple of the + * cipher block size. If the cipher is NULL for some + * reason, we don't do this trick at all because we gain + * nothing by it. + */ + if (ssh->cscipher) { + int stringlen, i; + + stringlen = (256 - ssh->deferred_len); + stringlen += ssh->cscipher->blksize - 1; + stringlen -= (stringlen % ssh->cscipher->blksize); + if (ssh->cscomp) { + /* + * Temporarily disable actual compression, + * so we can guarantee to get this string + * exactly the length we want it. The + * compression-disabling routine should + * return an integer indicating how many + * bytes we should adjust our string length + * by. + */ + stringlen -= ssh->cscomp->disable_compression(); + } + ssh2_pkt_init(ssh, SSH2_MSG_IGNORE); + ssh2_pkt_addstring_start(ssh); + for (i = 0; i < stringlen; i++) { + char c = (char) random_byte(); + ssh2_pkt_addstring_data(ssh, &c, 1); + } + ssh2_pkt_defer(ssh); + } + ssh_pkt_defersend(ssh); + logevent("Sent password"); + s->type = AUTH_TYPE_PASSWORD; + } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) { + if (s->curr_prompt == 0) { + ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE); + ssh2_pkt_adduint32(ssh, s->num_prompts); + } + if (s->need_pw) { /* only add pw if we just got one! */ + ssh2_pkt_addstring(ssh, s->password); + memset(s->password, 0, sizeof(s->password)); + s->curr_prompt++; + } + if (s->curr_prompt >= s->num_prompts) { + ssh2_pkt_send(ssh); + } else { + /* + * If there are prompts remaining, we set + * `gotit' so that we won't attempt to get + * another packet. Then we go back round the + * loop and will end up retrieving another + * prompt out of the existing packet. Funky or + * what? + */ + s->gotit = TRUE; + } + s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE; + } else { + c_write_str(ssh, "No supported authentication methods" + " left to try!\r\n"); + logevent("No supported authentications offered." + " Disconnecting"); + ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT); + ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION); + ssh2_pkt_addstring(ssh, "No supported authentication" + " methods available"); + ssh2_pkt_addstring(ssh, "en"); /* language tag */ + ssh2_pkt_send(ssh); + ssh->state = SSH_STATE_CLOSED; + crReturnV; + } + } + } while (!s->we_are_in); /* * Now we're authenticated for the connection protocol. The @@ -2019,110 +4935,793 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) /* * So now create a channel with a session in it. */ - ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN); - ssh2_pkt_addstring("session"); - ssh2_pkt_adduint32(100); /* as good as any */ - ssh2_pkt_adduint32(0xFFFFFFFFUL); /* very big window which we ignore */ - ssh2_pkt_adduint32(0xFFFFFFFFUL); /* very big max pkt size */ - ssh2_pkt_send(); + ssh->channels = newtree234(ssh_channelcmp); + ssh->mainchan = smalloc(sizeof(struct ssh_channel)); + ssh->mainchan->ssh = ssh; + ssh->mainchan->localid = alloc_channel_id(ssh); + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN); + ssh2_pkt_addstring(ssh, "session"); + ssh2_pkt_adduint32(ssh, ssh->mainchan->localid); + ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE; + ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */ + ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */ + ssh2_pkt_send(ssh); crWaitUntilV(ispkt); - if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) { - fatalbox("Server refused to open a session"); - /* FIXME: error data comes back in FAILURE packet */ + if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) { + bombout(("Server refused to open a session")); + crReturnV; + /* FIXME: error data comes back in FAILURE packet */ } - if (ssh2_pkt_getuint32() != 100) { - fatalbox("Server's channel confirmation cited wrong channel"); + if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) { + bombout(("Server's channel confirmation cited wrong channel")); + crReturnV; } - ssh_remote_channel = ssh2_pkt_getuint32(); - remote_winsize = ssh2_pkt_getuint32(); - remote_maxpkt = ssh2_pkt_getuint32(); + ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh); + ssh->mainchan->type = CHAN_MAINSESSION; + ssh->mainchan->closes = 0; + ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh); + ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh); + bufchain_init(&ssh->mainchan->v.v2.outbuffer); + add234(ssh->channels, ssh->mainchan); logevent("Opened channel for session"); /* + * Potentially enable X11 forwarding. + */ + if (cfg.x11_forward) { + char proto[20], data[64]; + logevent("Requesting X11 forwarding"); + x11_invent_auth(proto, sizeof(proto), data, sizeof(data)); + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); + ssh2_pkt_addstring(ssh, "x11-req"); + ssh2_pkt_addbool(ssh, 1); /* want reply */ + ssh2_pkt_addbool(ssh, 0); /* many connections */ + ssh2_pkt_addstring(ssh, proto); + ssh2_pkt_addstring(ssh, data); + ssh2_pkt_adduint32(ssh, 0); /* screen number */ + ssh2_pkt_send(ssh); + + do { + crWaitUntilV(ispkt); + if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(ssh); + } + } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + + if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { + if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) { + bombout(("Unexpected response to X11 forwarding request:" + " packet type %d", ssh->pktin.type)); + crReturnV; + } + logevent("X11 forwarding refused"); + } else { + logevent("X11 forwarding enabled"); + ssh->X11_fwd_enabled = TRUE; + } + } + + /* + * Enable port forwardings. + */ + { + char type; + int n; + int sport,dport,sserv,dserv; + char sports[256], dports[256], host[256]; + char buf[1024]; + struct servent *se; + + ssh->rportfwds = newtree234(ssh_rportcmp_ssh2); + /* Add port forwardings. */ + ssh->portfwd_strptr = cfg.portfwd; + while (*ssh->portfwd_strptr) { + type = *ssh->portfwd_strptr++; + n = 0; + while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') + sports[n++] = *ssh->portfwd_strptr++; + sports[n] = 0; + if (*ssh->portfwd_strptr == '\t') + ssh->portfwd_strptr++; + n = 0; + while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') + host[n++] = *ssh->portfwd_strptr++; + host[n] = 0; + if (*ssh->portfwd_strptr == ':') + ssh->portfwd_strptr++; + n = 0; + while (*ssh->portfwd_strptr) + dports[n++] = *ssh->portfwd_strptr++; + dports[n] = 0; + ssh->portfwd_strptr++; + dport = atoi(dports); + dserv = 0; + if (dport == 0) { + dserv = 1; + se = getservbyname(dports, NULL); + if (se != NULL) { + dport = ntohs(se->s_port); + } else { + sprintf(buf, + "Service lookup failed for destination port \"%s\"", + dports); + logevent(buf); + } + } + sport = atoi(sports); + sserv = 0; + if (sport == 0) { + sserv = 1; + se = getservbyname(sports, NULL); + if (se != NULL) { + sport = ntohs(se->s_port); + } else { + sprintf(buf, + "Service lookup failed for source port \"%s\"", + sports); + logevent(buf); + } + } + if (sport && dport) { + if (type == 'L') { + pfd_addforward(host, dport, sport); + sprintf(buf, "Local port %.*s%.*s%d%.*s forwarding to" + " %s:%.*s%.*s%d%.*s", + sserv ? strlen(sports) : 0, sports, + sserv, "(", sport, sserv, ")", + host, + dserv ? strlen(dports) : 0, dports, + dserv, "(", dport, dserv, ")"); + logevent(buf); + } else { + struct ssh_rportfwd *pf; + pf = smalloc(sizeof(*pf)); + strcpy(pf->dhost, host); + pf->dport = dport; + pf->sport = sport; + if (add234(ssh->rportfwds, pf) != pf) { + sprintf(buf, + "Duplicate remote port forwarding to %s:%d", + host, dport); + logevent(buf); + sfree(pf); + } else { + sprintf(buf, "Requesting remote port %.*s%.*s%d%.*s" + " forward to %s:%.*s%.*s%d%.*s", + sserv ? strlen(sports) : 0, sports, + sserv, "(", sport, sserv, ")", + host, + dserv ? strlen(dports) : 0, dports, + dserv, "(", dport, dserv, ")"); + logevent(buf); + ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST); + ssh2_pkt_addstring(ssh, "tcpip-forward"); + ssh2_pkt_addbool(ssh, 1);/* want reply */ + if (cfg.rport_acceptall) + ssh2_pkt_addstring(ssh, "0.0.0.0"); + else + ssh2_pkt_addstring(ssh, "127.0.0.1"); + ssh2_pkt_adduint32(ssh, sport); + ssh2_pkt_send(ssh); + + do { + crWaitUntilV(ispkt); + if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c) + continue;/* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(ssh); + } + } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + + if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) { + if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) { + bombout(("Unexpected response to port " + "forwarding request: packet type %d", + ssh->pktin.type)); + crReturnV; + } + logevent("Server refused this port forwarding"); + } else { + logevent("Remote port forwarding enabled"); + } + } + } + } + } + } + + /* + * Potentially enable agent forwarding. + */ + if (cfg.agentfwd && agent_exists()) { + logevent("Requesting OpenSSH-style agent forwarding"); + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); + ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com"); + ssh2_pkt_addbool(ssh, 1); /* want reply */ + ssh2_pkt_send(ssh); + + do { + crWaitUntilV(ispkt); + if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(ssh); + } + } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + + if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { + if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) { + bombout(("Unexpected response to agent forwarding request:" + " packet type %d", ssh->pktin.type)); + crReturnV; + } + logevent("Agent forwarding refused"); + } else { + logevent("Agent forwarding enabled"); + ssh->agentfwd_enabled = TRUE; + } + } + + /* * Now allocate a pty for the session. */ - ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); - ssh2_pkt_adduint32(ssh_remote_channel); /* recipient channel */ - ssh2_pkt_addstring("pty-req"); - ssh2_pkt_addbool(1); /* want reply */ - ssh2_pkt_addstring(cfg.termtype); - ssh2_pkt_adduint32(cols); - ssh2_pkt_adduint32(rows); - ssh2_pkt_adduint32(0); /* pixel width */ - ssh2_pkt_adduint32(0); /* pixel height */ - ssh2_pkt_addstring_start(); - ssh2_pkt_addstring_data("\0", 1); /* TTY_OP_END, no special options */ - ssh2_pkt_send(); - - do { /* FIXME: pay attention to these */ - crWaitUntilV(ispkt); - } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); - - if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { - if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { - fatalbox("Server got confused by pty request"); - } - c_write("Server refused to allocate pty\r\n", 32); + if (!cfg.nopty) { + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */ + ssh2_pkt_addstring(ssh, "pty-req"); + ssh2_pkt_addbool(ssh, 1); /* want reply */ + ssh2_pkt_addstring(ssh, cfg.termtype); + ssh2_pkt_adduint32(ssh, ssh->term_width); + ssh2_pkt_adduint32(ssh, ssh->term_height); + ssh2_pkt_adduint32(ssh, 0); /* pixel width */ + ssh2_pkt_adduint32(ssh, 0); /* pixel height */ + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */ + ssh2_pkt_send(ssh); + ssh->state = SSH_STATE_INTERMED; + + do { + crWaitUntilV(ispkt); + if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(ssh); + } + } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + + if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { + if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) { + bombout(("Unexpected response to pty request:" + " packet type %d", ssh->pktin.type)); + crReturnV; + } + c_write_str(ssh, "Server refused to allocate pty\r\n"); + ssh->editing = ssh->echoing = 1; + } else { + logevent("Allocated pty"); + } } else { - logevent("Allocated pty"); + ssh->editing = ssh->echoing = 1; } /* - * Start a shell. + * Start a shell or a remote command. We may have to attempt + * this twice if the config data has provided a second choice + * of command. */ - ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); - ssh2_pkt_adduint32(ssh_remote_channel); /* recipient channel */ - ssh2_pkt_addstring("shell"); - ssh2_pkt_addbool(1); /* want reply */ - ssh2_pkt_send(); - do { /* FIXME: pay attention to these */ - crWaitUntilV(ispkt); - } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); - if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { - if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { - fatalbox("Server got confused by shell request"); - } - fatalbox("Server refused to start a shell"); - } else { - logevent("Started a shell"); + while (1) { + int subsys; + char *cmd; + + if (ssh->fallback_cmd) { + subsys = cfg.ssh_subsys2; + cmd = cfg.remote_cmd_ptr2; + } else { + subsys = cfg.ssh_subsys; + cmd = cfg.remote_cmd_ptr; + } + + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */ + if (subsys) { + ssh2_pkt_addstring(ssh, "subsystem"); + ssh2_pkt_addbool(ssh, 1); /* want reply */ + ssh2_pkt_addstring(ssh, cmd); + } else if (*cmd) { + ssh2_pkt_addstring(ssh, "exec"); + ssh2_pkt_addbool(ssh, 1); /* want reply */ + ssh2_pkt_addstring(ssh, cmd); + } else { + ssh2_pkt_addstring(ssh, "shell"); + ssh2_pkt_addbool(ssh, 1); /* want reply */ + } + ssh2_pkt_send(ssh); + do { + crWaitUntilV(ispkt); + if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(ssh); + } + } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { + if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) { + bombout(("Unexpected response to shell/command request:" + " packet type %d", ssh->pktin.type)); + crReturnV; + } + /* + * We failed to start the command. If this is the + * fallback command, we really are finished; if it's + * not, and if the fallback command exists, try falling + * back to it before complaining. + */ + if (!ssh->fallback_cmd && cfg.remote_cmd_ptr2 != NULL) { + logevent("Primary command failed; attempting fallback"); + ssh->fallback_cmd = TRUE; + continue; + } + bombout(("Server refused to start a shell/command")); + crReturnV; + } else { + logevent("Started a shell/command"); + } + break; } + ssh->state = SSH_STATE_SESSION; + if (ssh->size_needed) + ssh_size(ssh, ssh->term_width, ssh->term_height); + if (ssh->eof_needed) + ssh_special(ssh, TS_EOF); + /* * Transfer data! */ - ssh_send_ok = 1; + ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */ + ssh->send_ok = 1; while (1) { crReturnV; + s->try_send = FALSE; if (ispkt) { - if (pktin.type == SSH2_MSG_CHANNEL_DATA || - pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) { - char *data; - int length; - if (ssh2_pkt_getuint32() != 100) - continue; /* wrong channel */ - if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA && - ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR) - continue; /* extended but not stderr */ - ssh2_pkt_getstring(&data, &length); - if (data) - c_write(data, length); - } else if (pktin.type == SSH2_MSG_DISCONNECT) { - ssh_state = SSH_STATE_CLOSED; - logevent("Received disconnect request"); - } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) { - continue; /* exit status et al; ignore (FIXME?) */ - } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { - continue; /* ignore for now (FIXME!) */ + if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA || + ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) { + char *data; + int length; + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA && + ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR) + continue; /* extended but not stderr */ + ssh2_pkt_getstring(ssh, &data, &length); + if (data) { + int bufsize; + c->v.v2.locwindow -= length; + switch (c->type) { + case CHAN_MAINSESSION: + bufsize = + from_backend(ssh->frontend, ssh->pktin.type == + SSH2_MSG_CHANNEL_EXTENDED_DATA, + data, length); + break; + case CHAN_X11: + bufsize = x11_send(c->u.x11.s, data, length); + break; + case CHAN_SOCKDATA: + bufsize = pfd_send(c->u.pfd.s, data, length); + break; + case CHAN_AGENT: + while (length > 0) { + if (c->u.a.lensofar < 4) { + int l = min(4 - c->u.a.lensofar, length); + memcpy(c->u.a.msglen + c->u.a.lensofar, + data, l); + data += l; + length -= l; + c->u.a.lensofar += l; + } + if (c->u.a.lensofar == 4) { + c->u.a.totallen = + 4 + GET_32BIT(c->u.a.msglen); + c->u.a.message = smalloc(c->u.a.totallen); + memcpy(c->u.a.message, c->u.a.msglen, 4); + } + if (c->u.a.lensofar >= 4 && length > 0) { + int l = + min(c->u.a.totallen - c->u.a.lensofar, + length); + memcpy(c->u.a.message + c->u.a.lensofar, + data, l); + data += l; + length -= l; + c->u.a.lensofar += l; + } + if (c->u.a.lensofar == c->u.a.totallen) { + void *reply, *sentreply; + int replylen; + agent_query(c->u.a.message, + c->u.a.totallen, &reply, + &replylen); + if (reply) + sentreply = reply; + else { + /* Fake SSH_AGENT_FAILURE. */ + sentreply = "\0\0\0\1\5"; + replylen = 5; + } + ssh2_add_channel_data(c, sentreply, replylen); + s->try_send = TRUE; + if (reply) + sfree(reply); + sfree(c->u.a.message); + c->u.a.lensofar = 0; + } + } + bufsize = 0; + break; + } + /* + * If we are not buffering too much data, + * enlarge the window again at the remote side. + */ + if (bufsize < OUR_V2_WINSIZE) + ssh2_set_window(c, OUR_V2_WINSIZE - bufsize); + } + } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) { + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + + if (c->type == CHAN_X11) { + /* + * Remote EOF on an X11 channel means we should + * wrap up and close the channel ourselves. + */ + x11_close(c->u.x11.s); + sshfwd_close(c); + } else if (c->type == CHAN_AGENT) { + sshfwd_close(c); + } else if (c->type == CHAN_SOCKDATA) { + pfd_close(c->u.pfd.s); + sshfwd_close(c); + } + } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) { + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c || ((int)c->remoteid) == -1) { + bombout(("Received CHANNEL_CLOSE for %s channel %d\n", + c ? "half-open" : "nonexistent", i)); + } + /* Do pre-close processing on the channel. */ + switch (c->type) { + case CHAN_MAINSESSION: + break; /* nothing to see here, move along */ + case CHAN_X11: + if (c->u.x11.s != NULL) + x11_close(c->u.x11.s); + sshfwd_close(c); + break; + case CHAN_AGENT: + sshfwd_close(c); + break; + case CHAN_SOCKDATA: + if (c->u.pfd.s != NULL) + pfd_close(c->u.pfd.s); + sshfwd_close(c); + break; + } + if (c->closes == 0) { + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE); + ssh2_pkt_adduint32(ssh, c->remoteid); + ssh2_pkt_send(ssh); + } + del234(ssh->channels, c); + bufchain_clear(&c->v.v2.outbuffer); + sfree(c); + + /* + * See if that was the last channel left open. + */ + if (count234(ssh->channels) == 0) { +#if 0 + /* + * We used to send SSH_MSG_DISCONNECT here, + * because I'd believed that _every_ conforming + * SSH2 connection had to end with a disconnect + * being sent by at least one side; apparently + * I was wrong and it's perfectly OK to + * unceremoniously slam the connection shut + * when you're done, and indeed OpenSSH feels + * this is more polite than sending a + * DISCONNECT. So now we don't. + */ + logevent("All channels closed. Disconnecting"); + ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT); + ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION); + ssh2_pkt_addstring(ssh, "All open channels closed"); + ssh2_pkt_addstring(ssh, "en"); /* language tag */ + ssh2_pkt_send(ssh); +#endif + ssh->state = SSH_STATE_CLOSED; + crReturnV; + } + continue; /* remote sends close; ignore (FIXME) */ + } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(ssh); + s->try_send = TRUE; + } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) { + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + if (c->type != CHAN_SOCKDATA_DORMANT) + continue; /* dunno why they're confirming this */ + c->remoteid = ssh2_pkt_getuint32(ssh); + c->type = CHAN_SOCKDATA; + c->v.v2.remwindow = ssh2_pkt_getuint32(ssh); + c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh); + if (c->u.pfd.s) + pfd_confirm(c->u.pfd.s); + if (c->closes) { + /* + * We have a pending close on this channel, + * which we decided on before the server acked + * the channel open. So now we know the + * remoteid, we can close it again. + */ + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE); + ssh2_pkt_adduint32(ssh, c->remoteid); + ssh2_pkt_send(ssh); + } + } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) { + unsigned i = ssh2_pkt_getuint32(ssh); + struct ssh_channel *c; + c = find234(ssh->channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + if (c->type != CHAN_SOCKDATA_DORMANT) + continue; /* dunno why they're failing this */ + + logevent("Forwarded connection refused by server"); + + pfd_close(c->u.pfd.s); + + del234(ssh->channels, c); + sfree(c); + } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) { + unsigned localid; + char *type; + int typelen, want_reply; + struct ssh_channel *c; + + localid = ssh2_pkt_getuint32(ssh); + ssh2_pkt_getstring(ssh, &type, &typelen); + want_reply = ssh2_pkt_getbool(ssh); + + /* + * First, check that the channel exists. Otherwise, + * we can instantly disconnect with a rude message. + */ + c = find234(ssh->channels, &localid, ssh_channelfind); + if (!c) { + char buf[80]; + sprintf(buf, "Received channel request for nonexistent" + " channel %d", localid); + logevent(buf); + ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT); + ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION); + ssh2_pkt_addstring(ssh, buf); + ssh2_pkt_addstring(ssh, "en"); /* language tag */ + ssh2_pkt_send(ssh); + connection_fatal("%s", buf); + ssh->state = SSH_STATE_CLOSED; + crReturnV; + } + + /* + * Having got the channel number, we now look at + * the request type string to see if it's something + * we recognise. + */ + if (typelen == 11 && !memcmp(type, "exit-status", 11) && + c == ssh->mainchan) { + /* We recognise "exit-status" on the primary channel. */ + char buf[100]; + ssh->exitcode = ssh2_pkt_getuint32(ssh); + sprintf(buf, "Server sent command exit status %d", + ssh->exitcode); + logevent(buf); + if (want_reply) { + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS); + ssh2_pkt_adduint32(ssh, c->remoteid); + ssh2_pkt_send(ssh); + } + } else { + /* + * This is a channel request we don't know + * about, so we now either ignore the request + * or respond with CHANNEL_FAILURE, depending + * on want_reply. + */ + if (want_reply) { + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE); + ssh2_pkt_adduint32(ssh, c->remoteid); + ssh2_pkt_send(ssh); + } + } + } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) { + char *type; + int typelen, want_reply; + + ssh2_pkt_getstring(ssh, &type, &typelen); + want_reply = ssh2_pkt_getbool(ssh); + + /* + * We currently don't support any global requests + * at all, so we either ignore the request or + * respond with REQUEST_FAILURE, depending on + * want_reply. + */ + if (want_reply) { + ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE); + ssh2_pkt_send(ssh); + } + } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) { + char *type; + int typelen; + char *error = NULL; + struct ssh_channel *c; + unsigned remid, winsize, pktsize; + ssh2_pkt_getstring(ssh, &type, &typelen); + c = smalloc(sizeof(struct ssh_channel)); + c->ssh = ssh; + + remid = ssh2_pkt_getuint32(ssh); + winsize = ssh2_pkt_getuint32(ssh); + pktsize = ssh2_pkt_getuint32(ssh); + + if (typelen == 3 && !memcmp(type, "x11", 3)) { + if (!ssh->X11_fwd_enabled) + error = "X11 forwarding is not enabled"; + else if (x11_init(&c->u.x11.s, cfg.x11_display, c) != + NULL) { + error = "Unable to open an X11 connection"; + } else { + c->type = CHAN_X11; + } + } else if (typelen == 15 && + !memcmp(type, "forwarded-tcpip", 15)) { + struct ssh_rportfwd pf, *realpf; + char *dummy; + int dummylen; + ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */ + pf.sport = ssh2_pkt_getuint32(ssh); + realpf = find234(ssh->rportfwds, &pf, NULL); + if (realpf == NULL) { + error = "Remote port is not recognised"; + } else { + char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost, + realpf->dport, c); + char buf[1024]; + sprintf(buf, "Received remote port open request for %s:%d", + realpf->dhost, realpf->dport); + logevent(buf); + if (e != NULL) { + sprintf(buf, "Port open failed: %s", e); + logevent(buf); + error = "Port open failed"; + } else { + logevent("Forwarded port opened successfully"); + c->type = CHAN_SOCKDATA; + } + } + } else if (typelen == 22 && + !memcmp(type, "auth-agent@openssh.com", 3)) { + if (!ssh->agentfwd_enabled) + error = "Agent forwarding is not enabled"; + else { + c->type = CHAN_AGENT; /* identify channel type */ + c->u.a.lensofar = 0; + } + } else { + error = "Unsupported channel type requested"; + } + + c->remoteid = remid; + if (error) { + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE); + ssh2_pkt_adduint32(ssh, c->remoteid); + ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED); + ssh2_pkt_addstring(ssh, error); + ssh2_pkt_addstring(ssh, "en"); /* language tag */ + ssh2_pkt_send(ssh); + sfree(c); + } else { + c->localid = alloc_channel_id(ssh); + c->closes = 0; + c->v.v2.locwindow = OUR_V2_WINSIZE; + c->v.v2.remwindow = winsize; + c->v.v2.remmaxpkt = pktsize; + bufchain_init(&c->v.v2.outbuffer); + add234(ssh->channels, c); + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); + ssh2_pkt_adduint32(ssh, c->remoteid); + ssh2_pkt_adduint32(ssh, c->localid); + ssh2_pkt_adduint32(ssh, c->v.v2.locwindow); + ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */ + ssh2_pkt_send(ssh); + } } else { - fatalbox("Strange packet received: type %d", pktin.type); + bombout(("Strange packet received: type %d", ssh->pktin.type)); + crReturnV; } } else { - /* FIXME: for now, ignore window size */ - ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA); - ssh2_pkt_adduint32(ssh_remote_channel); - ssh2_pkt_addstring_start(); - ssh2_pkt_addstring_data(in, inlen); - ssh2_pkt_send(); + /* + * We have spare data. Add it to the channel buffer. + */ + ssh2_add_channel_data(ssh->mainchan, in, inlen); + s->try_send = TRUE; + } + if (s->try_send) { + int i; + struct ssh_channel *c; + /* + * Try to send data on all channels if we can. + */ + for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) { + int bufsize = ssh2_try_send(c); + if (bufsize == 0) { + switch (c->type) { + case CHAN_MAINSESSION: + /* stdin need not receive an unthrottle + * notification since it will be polled */ + break; + case CHAN_X11: + x11_unthrottle(c->u.x11.s); + break; + case CHAN_AGENT: + /* agent sockets are request/response and need no + * buffer management */ + break; + case CHAN_SOCKDATA: + pfd_unthrottle(c->u.pfd.s); + break; + } + } + } } } @@ -2132,115 +5731,174 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) /* * Handle the top-level SSH2 protocol. */ -static void ssh2_protocol(unsigned char *in, int inlen, int ispkt) +static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt) { - if (do_ssh2_transport(in, inlen, ispkt) == 0) - return; - do_ssh2_authconn(in, inlen, ispkt); + if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0) + return; + do_ssh2_authconn(ssh, in, inlen, ispkt); } /* - * Called to set up the connection. Will arrange for WM_NETEVENT - * messages to be passed to the specified window, whose window - * procedure should then call telnet_msg(). + * Called to set up the connection. * * Returns an error message, or NULL on success. */ -static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) { +static char *ssh_init(void *frontend_handle, void **backend_handle, + char *host, int port, char **realhost, int nodelay) +{ char *p; - + Ssh ssh; + + ssh = smalloc(sizeof(*ssh)); + ssh->s = NULL; + ssh->cipher = NULL; + ssh->cscipher = NULL; + ssh->sccipher = NULL; + ssh->csmac = NULL; + ssh->scmac = NULL; + ssh->cscomp = NULL; + ssh->sccomp = NULL; + ssh->kex = NULL; + ssh->hostkey = NULL; + ssh->exitcode = -1; + ssh->state = SSH_STATE_PREPACKET; + ssh->size_needed = FALSE; + ssh->eof_needed = FALSE; + { + static const struct Packet empty = { 0, 0, NULL, NULL, 0 }; + ssh->pktin = ssh->pktout = empty; + } + ssh->deferred_send_data = NULL; + ssh->deferred_len = 0; + ssh->deferred_size = 0; + ssh->fallback_cmd = 0; + ssh->pkt_ctx = 0; + ssh->v2_outgoing_sequence = 0; + ssh->ssh1_rdpkt_crstate = 0; + ssh->ssh2_rdpkt_crstate = 0; + ssh->do_ssh_init_crstate = 0; + ssh->ssh_gotdata_crstate = 0; + ssh->ssh1_protocol_crstate = 0; + ssh->do_ssh1_login_crstate = 0; + ssh->do_ssh2_transport_crstate = 0; + ssh->do_ssh2_authconn_crstate = 0; + ssh->do_ssh_init_state = NULL; + ssh->do_ssh1_login_state = NULL; + ssh->do_ssh2_transport_state = NULL; + ssh->do_ssh2_authconn_state = NULL; + + *backend_handle = ssh; + #ifdef MSCRYPTOAPI - if(crypto_startup() == 0) + if (crypto_startup() == 0) return "Microsoft high encryption pack not installed!"; #endif - p = connect_to_host(host, port, realhost); - if (p != NULL) - return p; + ssh->frontend = frontend_handle; + ssh->term_width = cfg.width; + ssh->term_height = cfg.height; - if (!do_ssh_init()) - return "Protocol initialisation error"; + ssh->send_ok = 0; + ssh->editing = 0; + ssh->echoing = 0; + ssh->v1_throttle_count = 0; + ssh->overall_bufsize = 0; + ssh->fallback_cmd = 0; - if (hwnd && WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ | FD_CLOSE) == SOCKET_ERROR) - switch (WSAGetLastError()) { - case WSAENETDOWN: return "Network is down"; - default: return "WSAAsyncSelect(): unknown error"; - } + p = connect_to_host(ssh, host, port, realhost, nodelay); + if (p != NULL) + return p; return NULL; } /* - * Process a WM_NETEVENT message. Will return 0 if the connection - * has closed, or <0 for a socket error. + * Called to send data down the Telnet connection. */ -static int ssh_msg (WPARAM wParam, LPARAM lParam) { - int ret; - char buf[256]; +static int ssh_send(void *handle, char *buf, int len) +{ + Ssh ssh = (Ssh) handle; - /* - * Because reading less than the whole of the available pending - * data can generate an FD_READ event, we need to allow for the - * possibility that FD_READ may arrive with FD_CLOSE already in - * the queue; so it's possible that we can get here even with s - * invalid. If so, we return 1 and don't worry about it. - */ - if (s == INVALID_SOCKET) - return 1; + if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL) + return 0; - if (WSAGETSELECTERROR(lParam) != 0) - return -WSAGETSELECTERROR(lParam); + ssh->protocol(ssh, buf, len, 0); - switch (WSAGETSELECTEVENT(lParam)) { - case FD_READ: - case FD_CLOSE: - ret = recv(s, buf, sizeof(buf), 0); - if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK) - return 1; - if (ret < 0) /* any _other_ error */ - return -10000-WSAGetLastError(); - if (ret == 0) { - s = INVALID_SOCKET; - return 0; - } - ssh_gotdata (buf, ret); - if (ssh_state == SSH_STATE_CLOSED) { - closesocket(s); - s = INVALID_SOCKET; - return 0; - } - return 1; - } - return 1; /* shouldn't happen, but WTF */ + return ssh_sendbuffer(ssh); } /* - * Called to send data down the Telnet connection. + * Called to query the current amount of buffered stdin data. */ -static void ssh_send (char *buf, int len) { - if (s == INVALID_SOCKET) - return; +static int ssh_sendbuffer(void *handle) +{ + Ssh ssh = (Ssh) handle; + int override_value; + + if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL) + return 0; + + /* + * If the SSH socket itself has backed up, add the total backup + * size on that to any individual buffer on the stdin channel. + */ + override_value = 0; + if (ssh->throttled_all) + override_value = ssh->overall_bufsize; + + if (ssh->version == 1) { + return override_value; + } else if (ssh->version == 2) { + if (!ssh->mainchan || ssh->mainchan->closes > 0) + return override_value; + else + return (override_value + + bufchain_size(&ssh->mainchan->v.v2.outbuffer)); + } - ssh_protocol(buf, len, 0); + return 0; } /* - * Called to set the size of the window from Telnet's POV. + * Called to set the size of the window from SSH's POV. */ -static void ssh_size(void) { - switch (ssh_state) { +static void ssh_size(void *handle, int width, int height) +{ + Ssh ssh = (Ssh) handle; + + ssh->term_width = width; + ssh->term_height = height; + + switch (ssh->state) { case SSH_STATE_BEFORE_SIZE: + case SSH_STATE_PREPACKET: case SSH_STATE_CLOSED: break; /* do nothing */ case SSH_STATE_INTERMED: - size_needed = TRUE; /* buffer for later */ + ssh->size_needed = TRUE; /* buffer for later */ break; case SSH_STATE_SESSION: - if (!cfg.nopty) { - send_packet(SSH1_CMSG_WINDOW_SIZE, - PKT_INT, rows, PKT_INT, cols, - PKT_INT, 0, PKT_INT, 0, PKT_END); - } + if (!cfg.nopty) { + if (!term) + return; + if (ssh->version == 1) { + send_packet(ssh, SSH1_CMSG_WINDOW_SIZE, + PKT_INT, ssh->term_height, + PKT_INT, ssh->term_width, + PKT_INT, 0, PKT_INT, 0, PKT_END); + } else { + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); + ssh2_pkt_addstring(ssh, "window-change"); + ssh2_pkt_addbool(ssh, 0); + ssh2_pkt_adduint32(ssh, ssh->term_width); + ssh2_pkt_adduint32(ssh, ssh->term_height); + ssh2_pkt_adduint32(ssh, 0); + ssh2_pkt_adduint32(ssh, 0); + ssh2_pkt_send(ssh); + } + } + break; } } @@ -2249,194 +5907,169 @@ static void ssh_size(void) { * can send an EOF and collect resulting output (e.g. `plink * hostname sort'). */ -static void ssh_special (Telnet_Special code) { +static void ssh_special(void *handle, Telnet_Special code) +{ + Ssh ssh = (Ssh) handle; + if (code == TS_EOF) { - if (ssh_version = 1) { - send_packet(SSH1_CMSG_EOF, PKT_END); - } else { - ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF); - ssh2_pkt_adduint32(ssh_remote_channel); - ssh2_pkt_send(); - } + if (ssh->state != SSH_STATE_SESSION) { + /* + * Buffer the EOF in case we are pre-SESSION, so we can + * send it as soon as we reach SESSION. + */ + if (code == TS_EOF) + ssh->eof_needed = TRUE; + return; + } + if (ssh->version == 1) { + send_packet(ssh, SSH1_CMSG_EOF, PKT_END); + } else { + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF); + ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); + ssh2_pkt_send(ssh); + } + logevent("Sent EOF message"); + } else if (code == TS_PING) { + if (ssh->state == SSH_STATE_CLOSED + || ssh->state == SSH_STATE_PREPACKET) return; + if (ssh->version == 1) { + if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) + send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END); + } else { + ssh2_pkt_init(ssh, SSH2_MSG_IGNORE); + ssh2_pkt_addstring_start(ssh); + ssh2_pkt_send(ssh); + } } else { - /* do nothing */ + /* do nothing */ } } +void *new_sock_channel(void *handle, Socket s) +{ + Ssh ssh = (Ssh) handle; + struct ssh_channel *c; + c = smalloc(sizeof(struct ssh_channel)); + c->ssh = ssh; + + if (c) { + c->remoteid = -1; /* to be set when open confirmed */ + c->localid = alloc_channel_id(ssh); + c->closes = 0; + c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */ + c->u.pfd.s = s; + bufchain_init(&c->v.v2.outbuffer); + add234(ssh->channels, c); + } + return c; +} /* - * Read and decrypt one incoming SSH packet. - * (only used by pSCP) + * This is called when stdout/stderr (the entity to which + * from_backend sends data) manages to clear some backlog. */ -static void get_packet(void) +void ssh_unthrottle(void *handle, int bufsize) { - unsigned char buf[4096], *p; - long to_read; - int len; - - p = NULL; - len = 0; - - while ((to_read = s_rdpkt(&p, &len)) > 0) { - if (to_read > sizeof(buf)) to_read = sizeof(buf); - len = s_read(buf, to_read); - if (len != to_read) { - closesocket(s); - s = INVALID_SOCKET; - return; + Ssh ssh = (Ssh) handle; + if (ssh->version == 1) { + if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) { + ssh->v1_stdout_throttling = 0; + ssh1_throttle(ssh, -1); } - p = buf; + } else { + if (ssh->mainchan && ssh->mainchan->closes == 0) + ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize); } - - assert(len == 0); } -/* - * Receive a block of data over the SSH link. Block until - * all data is available. Return nr of bytes read (0 if lost connection). - * (only used by pSCP) - */ -int ssh_scp_recv(unsigned char *buf, int len) +void ssh_send_port_open(void *handle, void *channel, char *hostname, + int port, char *org) { - static int pending_input_len = 0; - static unsigned char *pending_input_ptr; - int to_read = len; + Ssh ssh = (Ssh) handle; + struct ssh_channel *c = (struct ssh_channel *)channel; + char buf[1024]; - if (pending_input_len >= to_read) { - memcpy(buf, pending_input_ptr, to_read); - pending_input_ptr += to_read; - pending_input_len -= to_read; - return len; - } - - if (pending_input_len > 0) { - memcpy(buf, pending_input_ptr, pending_input_len); - buf += pending_input_len; - to_read -= pending_input_len; - pending_input_len = 0; - } + sprintf(buf, "Opening forwarded connection to %.512s:%d", hostname, port); + logevent(buf); - if (s == INVALID_SOCKET) - return 0; - while (to_read > 0) { - get_packet(); - if (s == INVALID_SOCKET) - return 0; - if (pktin.type == SSH1_SMSG_STDOUT_DATA) { - int plen = GET_32BIT(pktin.body); - if (plen <= to_read) { - memcpy(buf, pktin.body + 4, plen); - buf += plen; - to_read -= plen; - } else { - memcpy(buf, pktin.body + 4, to_read); - pending_input_len = plen - to_read; - pending_input_ptr = pktin.body + 4 + to_read; - to_read = 0; - } - } else if (pktin.type == SSH1_SMSG_STDERR_DATA) { - int plen = GET_32BIT(pktin.body); - fwrite(pktin.body + 4, plen, 1, stderr); - } else if (pktin.type == SSH1_MSG_DISCONNECT) { - logevent("Received disconnect request"); - } else if (pktin.type == SSH1_SMSG_SUCCESS || - pktin.type == SSH1_SMSG_FAILURE) { - /* ignore */ - } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) { - char logbuf[100]; - sprintf(logbuf, "Remote exit status: %d", GET_32BIT(pktin.body)); - logevent(logbuf); - send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END); - logevent("Closing connection"); - closesocket(s); - s = INVALID_SOCKET; - } else { - fatalbox("Strange packet received: type %d", pktin.type); - } + if (ssh->version == 1) { + send_packet(ssh, SSH1_MSG_PORT_OPEN, + PKT_INT, c->localid, + PKT_STR, hostname, + PKT_INT, port, + //PKT_STR, , + PKT_END); + } else { + ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN); + ssh2_pkt_addstring(ssh, "direct-tcpip"); + ssh2_pkt_adduint32(ssh, c->localid); + c->v.v2.locwindow = OUR_V2_WINSIZE; + ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */ + ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */ + ssh2_pkt_addstring(ssh, hostname); + ssh2_pkt_adduint32(ssh, port); + /* + * We make up values for the originator data; partly it's + * too much hassle to keep track, and partly I'm not + * convinced the server should be told details like that + * about my local network configuration. + */ + ssh2_pkt_addstring(ssh, "client-side-connection"); + ssh2_pkt_adduint32(ssh, 0); + ssh2_pkt_send(ssh); } +} + - return len; +static Socket ssh_socket(void *handle) +{ + Ssh ssh = (Ssh) handle; + return ssh->s; } -/* - * Send a block of data over the SSH link. - * Block until all data is sent. - * (only used by pSCP) - */ -void ssh_scp_send(unsigned char *buf, int len) +static int ssh_sendok(void *handle) { - if (s == INVALID_SOCKET) - return; - send_packet(SSH1_CMSG_STDIN_DATA, - PKT_INT, len, PKT_DATA, buf, len, PKT_END); + Ssh ssh = (Ssh) handle; + return ssh->send_ok; } -/* - * Send an EOF notification to the server. - * (only used by pSCP) - */ -void ssh_scp_send_eof(void) +static int ssh_ldisc(void *handle, int option) { - if (s == INVALID_SOCKET) - return; - send_packet(SSH1_CMSG_EOF, PKT_END); + Ssh ssh = (Ssh) handle; + if (option == LD_ECHO) + return ssh->echoing; + if (option == LD_EDIT) + return ssh->editing; + return FALSE; +} + +static int ssh_return_exitcode(void *handle) +{ + Ssh ssh = (Ssh) handle; + return ssh->exitcode; } /* - * Set up the connection, login on the remote host and - * start execution of a command. - * Returns an error message, or NULL on success. - * (only used by pSCP) + * Gross hack: pscp will try to start SFTP but fall back to scp1 if + * that fails. This variable is the means by which scp.c can reach + * into the SSH code and find out which one it got. */ -char *ssh_scp_init(char *host, int port, char *cmd, char **realhost) +extern int ssh_fallback_cmd(void *handle) { - char buf[160], *p; - -#ifdef MSCRYPTOAPI - if (crypto_startup() == 0) - return "Microsoft high encryption pack not installed!"; -#endif - - p = connect_to_host(host, port, realhost); - if (p != NULL) - return p; - - random_init(); - - if (!do_ssh_init()) - return "Protocol initialisation error"; - - /* Exchange keys and login */ - do { - get_packet(); - if (s == INVALID_SOCKET) - return "Connection closed by remote host"; - } while (!do_ssh1_login(NULL, 0, 1)); - - if (ssh_state == SSH_STATE_CLOSED) { - closesocket(s); - s = INVALID_SOCKET; - return "Session initialisation error"; - } - - /* Execute command */ - sprintf(buf, "Sending command: %.100s", cmd); - logevent(buf); - send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END); - - return NULL; + Ssh ssh = (Ssh) handle; + return ssh->fallback_cmd; } -static SOCKET ssh_socket(void) { return s; } - -static int ssh_sendok(void) { return ssh_send_ok; } - Backend ssh_backend = { ssh_init, - ssh_msg, ssh_send, + ssh_sendbuffer, ssh_size, ssh_special, ssh_socket, - ssh_sendok + ssh_return_exitcode, + ssh_sendok, + ssh_ldisc, + ssh_unthrottle, + 22 };