X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/374330e25a6b51c40436fa869a381dd510790f6e..8eebd22198133e95ce25af1dd15dead0a5389371:/ssh.c diff --git a/ssh.c b/ssh.c index f80055c9..6cc79bff 100644 --- a/ssh.c +++ b/ssh.c @@ -1,8 +1,12 @@ +#include #include #include -#include +#include +#include #include "putty.h" +#include "tree234.h" +#include "ssh.h" #ifndef FALSE #define FALSE 0 @@ -11,7 +15,266 @@ #define TRUE 1 #endif -#include "ssh.h" +#define logevent(s) { logevent(s); \ + if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \ + { fprintf(stderr, "%s\n", s); fflush(stderr); } } + +#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \ + (s ? sk_close(s), s = NULL : 0), \ + 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 + +static int ssh_pkt_ctx = 0; + +#define translate(x) if (type == x) return #x +#define translatec(x,ctx) if (type == x && (ssh_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 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) | \ + ((unsigned long)(unsigned char)(cp)[1] << 16) | \ + ((unsigned long)(unsigned char)(cp)[2] << 8) | \ + ((unsigned long)(unsigned char)(cp)[3])) + +#define PUT_32BIT(cp, value) { \ + (cp)[0] = (unsigned char)((value) >> 24); \ + (cp)[1] = (unsigned char)((value) >> 16); \ + (cp)[2] = (unsigned char)((value) >> 8); \ + (cp)[3] = (unsigned char)(value); } + +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; @@ -29,666 +292,5355 @@ } 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)) -#ifndef FALSE -#define FALSE 0 -#endif -#ifndef TRUE -#define TRUE 1 -#endif +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); -static SOCKET s = INVALID_SOCKET; +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 unsigned char session_key[32]; -static struct ssh_cipher *cipher = NULL; +static void ssh2_pkt_init(int pkt_type); +static void ssh2_pkt_addbool(unsigned char value); +static void ssh2_pkt_adduint32(unsigned long value); +static void ssh2_pkt_addstring_start(void); +static void ssh2_pkt_addstring_str(char *data); +static void ssh2_pkt_addstring_data(char *data, int len); +static void ssh2_pkt_addstring(char *data); +static char *ssh2_mpint_fmt(Bignum b, int *len); +static void ssh2_pkt_addmp(Bignum b); +static int ssh2_pkt_construct(void); +static void ssh2_pkt_send(void); -static char *savedhost; +/* + * 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. + */ -static enum { - SSH_STATE_BEFORE_SIZE, - SSH_STATE_INTERMED, - SSH_STATE_SESSION -} ssh_state = SSH_STATE_BEFORE_SIZE; +#define SSH1_BUFFER_LIMIT 32768 +#define SSH_MAX_BACKLOG 32768 +#define OUR_V2_WINSIZE 16384 -static int size_needed = FALSE; +const static struct ssh_kex *kex_algs[] = { + &ssh_diffiehellman_gex, + &ssh_diffiehellman +}; -static void s_write (char *buf, int len) { - while (len > 0) { - int i = send (s, buf, len, 0); - if (i > 0) - len -= i, buf += i; - } -} +const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss }; -static int s_read (char *buf, int len) { - int ret = 0; - while (len > 0) { - int i = recv (s, buf, len, 0); - if (i > 0) - len -= i, buf += i, ret += i; - else - return i; - } - return ret; +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 +}; +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 +}; -static void c_write (char *buf, int len) { - while (len--) { - int new_head = (inbuf_head + 1) & INBUF_MASK; - int c = (unsigned char) *buf; - if (new_head != inbuf_reap) { - inbuf[inbuf_head] = *buf++; - inbuf_head = new_head; - } - } +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 { + unsigned remoteid, localid; + int type; + 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; int type; - unsigned long crc; unsigned char *data; unsigned char *body; + long savedpos; long maxlen; }; -static struct Packet pktin = { 0, 0, 0, NULL, 0 }; -static struct Packet pktout = { 0, 0, 0, NULL, 0 }; +static SHA_State exhash, exhashbase; -static void ssh_protocol(unsigned char *in, int inlen, int ispkt); -static void ssh_size(void); +static Socket s = NULL; -static void ssh_gotdata(unsigned char *data, int datalen) { - static long len, biglen, to_read; - static unsigned char c, *p; - static int i, pad; - static char padding[8]; - static unsigned char word[4]; +static unsigned char session_key[32]; +static int ssh1_compressing; +static int ssh1_remote_protoflags; +static int ssh1_local_protoflags; +static int ssh_agentfwd_enabled; +static int ssh_X11_fwd_enabled; +static int ssh_remote_bugs; +static const struct ssh_cipher *cipher = NULL; +static const struct ssh2_cipher *cscipher = NULL; +static const struct ssh2_cipher *sccipher = NULL; +static const struct ssh_mac *csmac = NULL; +static const struct ssh_mac *scmac = NULL; +static const struct ssh_compress *cscomp = NULL; +static const struct ssh_compress *sccomp = NULL; +static const struct ssh_kex *kex = NULL; +static const struct ssh_signkey *hostkey = NULL; +static unsigned char ssh2_session_id[20]; +int (*ssh_get_line) (const char *prompt, char *str, int maxlen, + int is_pw) = NULL; - crBegin; - while (1) { - for (i = len = 0; i < 4; i++) { - while (datalen == 0) - crReturnV; - len = (len << 8) + *data; - data++, datalen--; - } +static char *savedhost; +static int savedport; +static int ssh_send_ok; +static int ssh_echoing, ssh_editing; - pad = 8 - (len%8); +static tree234 *ssh_channels; /* indexed by local id */ +static struct ssh_channel *mainchan; /* primary session channel */ +static int ssh_exitcode = -1; - biglen = len + pad; +static tree234 *ssh_rportfwds; - len -= 5; /* type and CRC */ +static enum { + SSH_STATE_PREPACKET, + SSH_STATE_BEFORE_SIZE, + SSH_STATE_INTERMED, + SSH_STATE_SESSION, + SSH_STATE_CLOSED +} ssh_state = SSH_STATE_PREPACKET; - pktin.length = len; - if (pktin.maxlen < biglen) { - pktin.maxlen = biglen; - pktin.data = (pktin.data == NULL ? malloc(biglen) : - realloc(pktin.data, biglen)); - if (!pktin.data) - fatalbox("Out of memory"); - } +static int size_needed = FALSE, eof_needed = FALSE; - p = pktin.data, to_read = biglen; - while (to_read > 0) { - static int chunk; - chunk = to_read; - while (datalen == 0) - crReturnV; - if (chunk > datalen) - chunk = datalen; - memcpy(p, data, chunk); - data += chunk; - datalen -= chunk; - p += chunk; - to_read -= chunk; - } +static struct Packet pktin = { 0, 0, NULL, NULL, 0 }; +static struct Packet pktout = { 0, 0, NULL, NULL, 0 }; +static unsigned char *deferred_send_data = NULL; +static int deferred_len = 0, deferred_size = 0; - if (cipher) - cipher->decrypt(pktin.data, biglen); +/* + * 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 ssh_fallback_cmd = 0; - pktin.type = pktin.data[pad]; - pktin.body = pktin.data+pad+1; +static int ssh_version; +static int ssh1_throttle_count; +static int ssh_overall_bufsize; +static int ssh_throttled_all; +static int ssh1_stdout_throttling; +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 ssh_special(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(int enable, int bufsize); +static void ssh2_set_window(struct ssh_channel *c, unsigned newwin); +static int (*s_rdpkt) (unsigned char **data, int *datalen); +static int ssh_sendbuffer(void); - if (pktin.type == 36) { /* SSH_MSG_DEBUG */ - /* FIXME: log it */ - } else - ssh_protocol(NULL, 0, 1); - } - crFinishV; +static struct rdpkt1_state_tag { + long len, pad, biglen, to_read; + unsigned long realcrc, gotcrc; + unsigned char *p; + int i; + int chunk; +} rdpkt1_state; + +static struct rdpkt2_state_tag { + long len, pad, payload, packetlen, maclen; + int i; + int cipherblk; + unsigned long incoming_sequence; +} rdpkt2_state; + +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 void s_wrpkt_start(int type, int len) { - int pad, biglen; +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; +} - len += 5; /* type and CRC */ - pad = 8 - (len%8); - biglen = len + pad; +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; - pktout.length = len-5; - if (pktout.maxlen < biglen) { - pktout.maxlen = biglen; - pktout.data = (pktout.data == NULL ? malloc(biglen) : - realloc(pktout.data, biglen)); - if (!pktout.data) - fatalbox("Out of memory"); + if (a->sport > b->sport) + return +1; + if (a->sport < b->sport) + return -1; + return 0; +} + +static int alloc_channel_id(void) +{ + 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; +} - pktout.type = type; - pktout.body = pktout.data+4+pad+1; +static void c_write(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(1, buf, len); } -static void s_wrpkt(void) { - int pad, len, biglen, i; - unsigned long crc; +static void c_write_untrusted(char *buf, int len) +{ + int i; + for (i = 0; i < len; i++) { + if (buf[i] == '\n') + c_write("\r\n", 2); + else if ((buf[i] & 0x60) || (buf[i] == '\r')) + c_write(buf + i, 1); + } +} - len = pktout.length + 5; /* type and CRC */ - pad = 8 - (len%8); - biglen = len + pad; +static void c_write_str(char *buf) +{ + c_write(buf, strlen(buf)); +} - pktout.body[-1] = pktout.type; - for (i=0; i> 24) & 0xFF); - pktout.data[biglen+1] = (unsigned char) ((crc >> 16) & 0xFF); - pktout.data[biglen+2] = (unsigned char) ((crc >> 8) & 0xFF); - pktout.data[biglen+3] = (unsigned char) (crc & 0xFF); + crBegin; - pktout.data[0] = (len >> 24) & 0xFF; - pktout.data[1] = (len >> 16) & 0xFF; - pktout.data[2] = (len >> 8) & 0xFF; - pktout.data[3] = len & 0xFF; + next_packet: - if (cipher) - cipher->encrypt(pktout.data+4, biglen); + pktin.type = 0; + pktin.length = 0; - s_write(pktout.data, biglen+4); -} + for (st->i = st->len = 0; st->i < 4; st->i++) { + while ((*datalen) == 0) + crReturn(4 - st->i); + st->len = (st->len << 8) + **data; + (*data)++, (*datalen)--; + } -static int do_ssh_init(void) { - char c; - char version[10]; - char vstring[40]; - int i; + st->pad = 8 - (st->len % 8); + st->biglen = st->len + st->pad; + pktin.length = st->len - 5; -#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; - } -#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 - if (s_read(&c,1) != 1 || c != '-') return 0; - i = 0; - while (1) { - if (s_read(&c,1) != 1) - return 0; - if (i >= 0) { - if (c == '-') { - version[i] = '\0'; - i = -1; - } else if (i < sizeof(version)-1) - version[i++] = c; - } - else if (c == '\n') - break; + if (pktin.maxlen < st->biglen) { + pktin.maxlen = st->biglen; + pktin.data = (pktin.data == NULL ? smalloc(st->biglen + APIEXTRA) : + srealloc(pktin.data, st->biglen + APIEXTRA)); + if (!pktin.data) + fatalbox("Out of memory"); } - sprintf(vstring, "SSH-%s-7.7.7\n", - (strcmp(version, "1.5") <= 0 ? version : "1.5")); - s_write(vstring, strlen(vstring)); -} + st->to_read = st->biglen; + st->p = 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; + } -static void ssh_protocol(unsigned char *in, int inlen, int ispkt) { - int i, j, len; - unsigned char session_id[16]; - unsigned char *rsabuf, *keystr1, *keystr2; - unsigned char cookie[8]; - struct RSAKey servkey, hostkey; - struct MD5Context md5c; + if (cipher && detect_attack(pktin.data, st->biglen, NULL)) { + bombout(("Network attack (CRC compensation) detected!")); + crReturn(0); + } - extern struct ssh_cipher ssh_3des; + if (cipher) + cipher->decrypt(pktin.data, st->biglen); - crBegin; + st->realcrc = crc32(pktin.data, st->biglen - 4); + st->gotcrc = GET_32BIT(pktin.data + st->biglen - 4); + if (st->gotcrc != st->realcrc) { + bombout(("Incorrect CRC received on packet")); + crReturn(0); + } - random_init(); + pktin.body = pktin.data + st->pad + 1; - while (!ispkt) - crReturnV; + if (ssh1_compressing) { + unsigned char *decompblk; + int decomplen; + zlib_decompress_block(pktin.body - 1, pktin.length + 1, + &decompblk, &decomplen); - if (pktin.type != 2) - fatalbox("Public key packet not received"); + if (pktin.maxlen < st->pad + decomplen) { + pktin.maxlen = st->pad + decomplen; + pktin.data = srealloc(pktin.data, pktin.maxlen + APIEXTRA); + pktin.body = pktin.data + st->pad + 1; + if (!pktin.data) + fatalbox("Out of memory"); + } - memcpy(cookie, pktin.body, 8); + memcpy(pktin.body - 1, decompblk, decomplen); + sfree(decompblk); + pktin.length = decomplen - 1; + } - MD5Init(&md5c); + pktin.type = pktin.body[-1]; - i = makekey(pktin.body+8, &servkey, &keystr1); + log_packet(PKT_INCOMING, pktin.type, ssh1_pkt_type(pktin.type), + pktin.body, pktin.length); - j = makekey(pktin.body+8+i, &hostkey, &keystr2); + 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 stringlen = GET_32BIT(pktin.body); + if (stringlen + 4 != pktin.length) { + bombout(("Received data packet with bogus string length")); + crReturn(0); + } + } - MD5Update(&md5c, keystr2, hostkey.bytes); - MD5Update(&md5c, keystr1, servkey.bytes); - MD5Update(&md5c, pktin.body, 8); + if (pktin.type == SSH1_MSG_DEBUG) { + /* log debug message */ + char buf[80]; + int stringlen = GET_32BIT(pktin.body); + strcpy(buf, "Remote: "); + if (stringlen > 70) + stringlen = 70; + memcpy(buf + 8, pktin.body + 4, stringlen); + buf[8 + stringlen] = '\0'; + logevent(buf); + goto next_packet; + } else if (pktin.type == SSH1_MSG_IGNORE) { + /* do nothing */ + goto next_packet; + } - MD5Final(session_id, &md5c); + if (pktin.type == SSH1_MSG_DISCONNECT) { + /* log reason code in disconnect message */ + char buf[256]; + unsigned msglen = GET_32BIT(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, pktin.body + 4, msglen); + buf[nowlen + msglen] = '\0'; + logevent(buf); + bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen)); + crReturn(0); + } - for (i=0; i<32; i++) - session_key[i] = random_byte(); + crFinish(0); +} - len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes); +static int ssh2_rdpkt(unsigned char **data, int *datalen) +{ + struct rdpkt2_state_tag *st = &rdpkt2_state; - rsabuf = malloc(len); - if (!rsabuf) - fatalbox("Out of memory"); + crBegin; - verify_ssh_host_key(savedhost, &hostkey); + next_packet: + pktin.type = 0; + pktin.length = 0; + if (sccipher) + st->cipherblk = sccipher->blksize; + else + st->cipherblk = 8; + if (st->cipherblk < 8) + st->cipherblk = 8; - for (i=0; i<32; i++) { - rsabuf[i] = session_key[i]; - if (i < 16) - rsabuf[i] ^= session_id[i]; + if (pktin.maxlen < st->cipherblk) { + pktin.maxlen = st->cipherblk; + pktin.data = + (pktin.data == + NULL ? smalloc(st->cipherblk + + APIEXTRA) : srealloc(pktin.data, + st->cipherblk + + APIEXTRA)); + if (!pktin.data) + fatalbox("Out of memory"); } - if (hostkey.bytes > servkey.bytes) { - rsaencrypt(rsabuf, 32, &servkey); - rsaencrypt(rsabuf, servkey.bytes, &hostkey); - } else { - rsaencrypt(rsabuf, 32, &hostkey); - rsaencrypt(rsabuf, hostkey.bytes, &servkey); + /* + * Acquire and decrypt the first block of the packet. This will + * contain the length and padding details. + */ + for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) { + while ((*datalen) == 0) + crReturn(st->cipherblk - st->i); + pktin.data[st->i] = *(*data)++; + (*datalen)--; } - s_wrpkt_start(3, len+15); - pktout.body[0] = 3; /* SSH_CIPHER_3DES */ - memcpy(pktout.body+1, cookie, 8); - pktout.body[9] = (len*8) >> 8; - pktout.body[10] = (len*8) & 0xFF; - memcpy(pktout.body+11, rsabuf, len); - pktout.body[len+11] = pktout.body[len+12] = 0; /* protocol flags */ - pktout.body[len+13] = pktout.body[len+14] = 0; - s_wrpkt(); + if (sccipher) + sccipher->decrypt(pktin.data, st->cipherblk); - free(rsabuf); + /* + * Now get the length and padding figures. + */ + st->len = GET_32BIT(pktin.data); + st->pad = pktin.data[4]; - cipher = &ssh_3des; - cipher->sesskey(session_key); + /* + * This enables us to deduce the payload length. + */ + st->payload = st->len - st->pad - 1; - do { crReturnV; } while (!ispkt); + pktin.length = st->payload + 5; + + /* + * So now we can work out the total packet length. + */ + st->packetlen = st->len + 4; + st->maclen = scmac ? scmac->len : 0; - if (pktin.type != 14) - fatalbox("Encryption not successfully enabled"); + /* + * Adjust memory allocation if packet is too big. + */ + if (pktin.maxlen < st->packetlen + st->maclen) { + pktin.maxlen = st->packetlen + st->maclen; + pktin.data = + (pktin.data == + NULL ? smalloc(pktin.maxlen + APIEXTRA) : srealloc(pktin.data, + pktin.maxlen + + + APIEXTRA)); + if (!pktin.data) + fatalbox("Out of memory"); + } - fflush(stdout); + /* + * Read and decrypt the remainder of the packet. + */ + for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen; + st->i++) { + while ((*datalen) == 0) + crReturn(st->packetlen + st->maclen - st->i); + pktin.data[st->i] = *(*data)++; + (*datalen)--; + } + /* Decrypt everything _except_ the MAC. */ + if (sccipher) + sccipher->decrypt(pktin.data + st->cipherblk, + st->packetlen - st->cipherblk); + + /* + * Check the MAC. + */ + if (scmac + && !scmac->verify(pktin.data, st->len + 4, + st->incoming_sequence)) { + bombout(("Incorrect MAC received on packet")); + crReturn(0); + } + st->incoming_sequence++; /* whether or not we MACed */ + + /* + * Decompress packet payload. + */ { - static char username[100]; - static int pos = 0; - static char c; - if (!*cfg.username) { - c_write("login as: ", 10); - while (pos >= 0) { - do { crReturnV; } while (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 <= '~' && pos < 40) { - username[pos++] = c; - c_write(&c, 1); - } - break; - } + unsigned char *newpayload; + int newlen; + if (sccomp && sccomp->decompress(pktin.data + 5, pktin.length - 5, + &newpayload, &newlen)) { + if (pktin.maxlen < newlen + 5) { + pktin.maxlen = newlen + 5; + pktin.data = + (pktin.data == + NULL ? smalloc(pktin.maxlen + + APIEXTRA) : srealloc(pktin.data, + pktin.maxlen + + APIEXTRA)); + if (!pktin.data) + fatalbox("Out of memory"); } - c_write("\r\n", 2); - username[strcspn(username, "\n\r")] = '\0'; - } else { - char stuff[200]; - strncpy(username, cfg.username, 99); - username[99] = '\0'; - sprintf(stuff, "Sent username \"%s\".\r\n", username); - c_write(stuff, strlen(stuff)); + pktin.length = 5 + newlen; + memcpy(pktin.data + 5, newpayload, newlen); + sfree(newpayload); } - s_wrpkt_start(4, 4+strlen(username)); - pktout.body[0] = pktout.body[1] = pktout.body[2] = 0; - pktout.body[3] = strlen(username); - memcpy(pktout.body+4, username, strlen(username)); - s_wrpkt(); } - do { crReturnV; } while (!ispkt); + pktin.savedpos = 6; + pktin.type = pktin.data[5]; - while (pktin.type == 15) { - static char password[100]; - static int pos; - static char c; - c_write("password: ", 10); - pos = 0; - while (pos >= 0) { - do { crReturnV; } while (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 <= '~' && pos < 40) - password[pos++] = c; - break; - } + log_packet(PKT_INCOMING, pktin.type, ssh2_pkt_type(pktin.type), + pktin.data+6, pktin.length-6); + + switch (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(pktin.data + 6); + unsigned msglen = GET_32BIT(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, 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 = pktin.body[6]; */ + int stringlen = GET_32BIT(pktin.data+7); + int prefix; + strcpy(buf, "Remote debug message: "); + prefix = strlen(buf); + if (stringlen > sizeof(buf)-prefix-1) + stringlen = sizeof(buf)-prefix-1; + memcpy(buf + prefix, pktin.data + 11, stringlen); + buf[prefix + stringlen] = '\0'; + logevent(buf); } - c_write("\r\n", 2); - s_wrpkt_start(9, 4+strlen(password)); - pktout.body[0] = pktout.body[1] = pktout.body[2] = 0; - pktout.body[3] = strlen(password); - memcpy(pktout.body+4, password, strlen(password)); - s_wrpkt(); - memset(password, 0, strlen(password)); - do { crReturnV; } while (!ispkt); - if (pktin.type == 15) { - c_write("Access denied\r\n", 15); - } else if (pktin.type != 14) { - fatalbox("Strange packet received, type %d", pktin.type); - } - } - - i = strlen(cfg.termtype); - s_wrpkt_start(10, i+5*4+1); - pktout.body[0] = (i >> 24) & 0xFF; - pktout.body[1] = (i >> 16) & 0xFF; - pktout.body[2] = (i >> 8) & 0xFF; - pktout.body[3] = i & 0xFF; - memcpy(pktout.body+4, cfg.termtype, i); - i += 4; - pktout.body[i++] = (rows >> 24) & 0xFF; - pktout.body[i++] = (rows >> 16) & 0xFF; - pktout.body[i++] = (rows >> 8) & 0xFF; - pktout.body[i++] = rows & 0xFF; - pktout.body[i++] = (cols >> 24) & 0xFF; - pktout.body[i++] = (cols >> 16) & 0xFF; - pktout.body[i++] = (cols >> 8) & 0xFF; - pktout.body[i++] = cols & 0xFF; - memset(pktout.body+i, 0, 9); /* 0 pixwidth, 0 pixheight, 0.b endofopt */ - s_wrpkt(); - ssh_state = SSH_STATE_INTERMED; - do { crReturnV; } while (!ispkt); - if (pktin.type != 14 && pktin.type != 15) { - fatalbox("Protocol confusion"); - } else if (pktin.type == 15) { - c_write("Server refused to allocate pty\r\n", 32); + 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(SSH2_MSG_UNIMPLEMENTED); + ssh2_pkt_adduint32(st->incoming_sequence - 1); + ssh2_pkt_send(); + break; } - s_wrpkt_start(12, 0); - s_wrpkt(); + crFinish(0); +} - ssh_state = SSH_STATE_SESSION; - if (size_needed) - ssh_size(); +static void ssh1_pktout_size(int len) +{ + int pad, biglen; - while (1) { + len += 5; /* type and CRC */ + pad = 8 - (len % 8); + biglen = len + pad; + + pktout.length = len - 5; + if (pktout.maxlen < biglen) { + pktout.maxlen = biglen; +#ifdef MSCRYPTOAPI + /* Allocate enough buffer space for extra block + * for MS CryptEncrypt() */ + pktout.data = (pktout.data == NULL ? smalloc(biglen + 12) : + srealloc(pktout.data, biglen + 12)); +#else + pktout.data = (pktout.data == NULL ? smalloc(biglen + 4) : + srealloc(pktout.data, biglen + 4)); +#endif + if (!pktout.data) + fatalbox("Out of memory"); + } + pktout.body = pktout.data + 4 + pad + 1; +} + +static void s_wrpkt_start(int type, int len) +{ + ssh1_pktout_size(len); + pktout.type = type; +} + +static int s_wrpkt_prepare(void) +{ + int pad, len, biglen, i; + unsigned long crc; + + pktout.body[-1] = pktout.type; + + log_packet(PKT_OUTGOING, pktout.type, ssh1_pkt_type(pktout.type), + pktout.body, pktout.length); + + if (ssh1_compressing) { + unsigned char *compblk; + int complen; + zlib_compress_block(pktout.body - 1, pktout.length + 1, + &compblk, &complen); + ssh1_pktout_size(complen - 1); + memcpy(pktout.body - 1, compblk, complen); + sfree(compblk); + } + + len = pktout.length + 5; /* type and CRC */ + pad = 8 - (len % 8); + biglen = len + pad; + + for (i = 0; i < pad; i++) + pktout.data[i + 4] = random_byte(); + crc = crc32(pktout.data + 4, biglen - 4); + PUT_32BIT(pktout.data + biglen, crc); + PUT_32BIT(pktout.data, len); + + if (cipher) + cipher->encrypt(pktout.data + 4, biglen); + + return biglen + 4; +} + +static void s_wrpkt(void) +{ + int len, backlog; + len = s_wrpkt_prepare(); + backlog = sk_write(s, pktout.data, len); + if (backlog > SSH_MAX_BACKLOG) + ssh_throttle_all(1, backlog); +} + +static void s_wrpkt_defer(void) +{ + int len; + len = s_wrpkt_prepare(); + if (deferred_len + len > deferred_size) { + deferred_size = deferred_len + len + 128; + deferred_send_data = srealloc(deferred_send_data, deferred_size); + } + memcpy(deferred_send_data + deferred_len, pktout.data, len); + deferred_len += len; +} + +/* + * Construct a packet with the specified contents. + */ +static void construct_packet(int pkttype, va_list ap1, va_list ap2) +{ + unsigned char *p, *argp, argchar; + unsigned long argint; + int pktlen, argtype, arglen; + Bignum bn; + + pktlen = 0; + while ((argtype = va_arg(ap1, int)) != PKT_END) { + switch (argtype) { + case PKT_INT: + (void) va_arg(ap1, int); + pktlen += 4; + break; + case PKT_CHAR: + (void) va_arg(ap1, char); + pktlen++; + break; + case PKT_DATA: + (void) va_arg(ap1, unsigned char *); + arglen = va_arg(ap1, int); + pktlen += arglen; + break; + case PKT_STR: + argp = va_arg(ap1, unsigned char *); + arglen = strlen(argp); + pktlen += 4 + arglen; + break; + case PKT_BIGNUM: + bn = va_arg(ap1, Bignum); + pktlen += ssh1_bignum_length(bn); + break; + default: + assert(0); + } + } + + s_wrpkt_start(pkttype, pktlen); + p = pktout.body; + + while ((argtype = va_arg(ap2, int)) != PKT_END) { + switch (argtype) { + case PKT_INT: + argint = va_arg(ap2, int); + PUT_32BIT(p, argint); + p += 4; + break; + case PKT_CHAR: + argchar = va_arg(ap2, unsigned char); + *p = argchar; + p++; + break; + case PKT_DATA: + argp = va_arg(ap2, unsigned char *); + arglen = va_arg(ap2, int); + memcpy(p, argp, arglen); + p += arglen; + break; + case PKT_STR: + 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(ap2, Bignum); + p += ssh1_write_bignum(p, bn); + break; + } + } +} + +static void send_packet(int pkttype, ...) +{ + va_list ap1, ap2; + va_start(ap1, pkttype); + va_start(ap2, pkttype); + construct_packet(pkttype, ap1, ap2); + s_wrpkt(); +} + +static void defer_packet(int pkttype, ...) +{ + va_list ap1, ap2; + va_start(ap1, pkttype); + va_start(ap2, pkttype); + construct_packet(pkttype, ap1, ap2); + s_wrpkt_defer(); +} + +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++; + av = strtoul(ae, &ae, 10); + bv = strtoul(be, &be, 10); + if (av != bv) + return (av < bv ? -1 : +1); + return 0; +} + + +/* + * Utility routines for putting an SSH-protocol `string' and + * `uint32' into a SHA state. + */ +#include +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. + */ +static void ssh2_pkt_ensure(int length) +{ + if (pktout.maxlen < length) { + pktout.maxlen = length + 256; + pktout.data = + (pktout.data == + NULL ? smalloc(pktout.maxlen + + APIEXTRA) : srealloc(pktout.data, + pktout.maxlen + + APIEXTRA)); + if (!pktout.data) + fatalbox("Out of memory"); + } +} +static void ssh2_pkt_adddata(void *data, int len) +{ + pktout.length += len; + ssh2_pkt_ensure(pktout.length); + memcpy(pktout.data + pktout.length - len, data, len); +} +static void ssh2_pkt_addbyte(unsigned char byte) +{ + ssh2_pkt_adddata(&byte, 1); +} +static void ssh2_pkt_init(int pkt_type) +{ + pktout.length = 5; + ssh2_pkt_addbyte((unsigned char) pkt_type); +} +static void ssh2_pkt_addbool(unsigned char value) +{ + ssh2_pkt_adddata(&value, 1); +} +static void ssh2_pkt_adduint32(unsigned long value) +{ + unsigned char x[4]; + PUT_32BIT(x, value); + ssh2_pkt_adddata(x, 4); +} +static void ssh2_pkt_addstring_start(void) +{ + ssh2_pkt_adduint32(0); + pktout.savedpos = pktout.length; +} +static 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_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(char *data) +{ + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_str(data); +} +static char *ssh2_mpint_fmt(Bignum b, int *len) +{ + unsigned char *p; + int i, n = (bignum_bitcount(b) + 7) / 8; + p = smalloc(n + 1); + if (!p) + fatalbox("out of memory"); + p[0] = 0; + for (i = 1; i <= n; i++) + p[i] = bignum_byte(b, n - i); + i = 0; + 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; +} +static void ssh2_pkt_addmp(Bignum b) +{ + unsigned char *p; + int len; + p = ssh2_mpint_fmt(b, &len); + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(p, len); + sfree(p); +} + +/* + * Construct an SSH2 final-form packet: compress it, encrypt it, + * put the MAC on it. Final packet, ready to be sent, is stored in + * pktout.data. Total length is returned. + */ +static int ssh2_pkt_construct(void) +{ + int cipherblk, maclen, padding, i; + static unsigned long outgoing_sequence = 0; + + log_packet(PKT_OUTGOING, pktout.data[5], ssh2_pkt_type(pktout.data[5]), + pktout.data + 6, pktout.length - 6); + + /* + * Compress packet payload. + */ + { + unsigned char *newpayload; + int newlen; + if (cscomp && cscomp->compress(pktout.data + 5, pktout.length - 5, + &newpayload, &newlen)) { + pktout.length = 5; + ssh2_pkt_adddata(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 = cscipher ? cscipher->blksize : 8; /* block size */ + cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */ + padding = 4; + padding += + (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk; + maclen = csmac ? csmac->len : 0; + ssh2_pkt_ensure(pktout.length + padding + maclen); + 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 */ + + if (cscipher) + cscipher->encrypt(pktout.data, pktout.length + padding); + + /* Ready-to-send packet starts at pktout.data. We return length. */ + return pktout.length + padding + maclen; +} + +/* + * Construct and send an SSH2 packet immediately. + */ +static void ssh2_pkt_send(void) +{ + int len; + int backlog; + len = ssh2_pkt_construct(); + backlog = sk_write(s, pktout.data, len); + if (backlog > SSH_MAX_BACKLOG) + ssh_throttle_all(1, backlog); +} + +/* + * 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(void) +{ + int len = ssh2_pkt_construct(); + if (deferred_len + len > deferred_size) { + deferred_size = deferred_len + len + 128; + deferred_send_data = srealloc(deferred_send_data, deferred_size); + } + memcpy(deferred_send_data + deferred_len, pktout.data, len); + deferred_len += len; +} + +/* + * Send the whole deferred data block constructed by + * ssh2_pkt_defer() or SSH1's defer_packet(). + */ +static void ssh_pkt_defersend(void) +{ + int backlog; + backlog = sk_write(s, deferred_send_data, deferred_len); + deferred_len = deferred_size = 0; + sfree(deferred_send_data); + deferred_send_data = NULL; + if (backlog > SSH_MAX_BACKLOG) + ssh_throttle_all(1, backlog); +} + +#if 0 +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(("\n")); + sfree(p); +} +#endif + +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); + sfree(p); +} + +/* + * SSH2 packet decode functions. + */ +static unsigned long ssh2_pkt_getuint32(void) +{ + 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; + return value; +} +static int ssh2_pkt_getbool(void) +{ + unsigned long value; + if (pktin.length - pktin.savedpos < 1) + return 0; /* arrgh, no way to decline (FIXME?) */ + value = pktin.data[pktin.savedpos] != 0; + pktin.savedpos++; + return value; +} +static void ssh2_pkt_getstring(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; +} +static Bignum ssh2_pkt_getmp(void) +{ + char *p; + int length; + Bignum b; + + ssh2_pkt_getstring(&p, &length); + if (!p) + return NULL; + if (p[0] & 0x80) { + bombout(("internal error: Can't handle negative mpints")); + return NULL; + } + b = bignum_from_bytes(p, length); + return b; +} + +/* + * Examine the remote side's version string and compare it against + * a list of known buggy implementations. + */ +static void ssh_detect_bugs(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 (!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 (!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 (!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 (!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"); + } +} + +static int do_ssh_init(unsigned char c) +{ + static int vslen; + static char version[10]; + static char *vstring; + static int vstrsize; + static char *vlog; + static int i; + + crBegin; + + /* Search for the string "SSH-" in the input. */ + i = 0; + while (1) { + 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') + i = transS[i]; + else if (c == 'H') + i = transH[i]; + else if (c == '-') + i = transminus[i]; + else + i = 0; + if (i < 0) + break; + crReturn(1); /* get another character */ + } + + vstrsize = 16; + vstring = smalloc(vstrsize); + strcpy(vstring, "SSH-"); + vslen = 4; + i = 0; + while (1) { + crReturn(1); /* get another char */ + if (vslen >= vstrsize - 1) { + vstrsize += 16; + vstring = srealloc(vstring, vstrsize); + } + vstring[vslen++] = c; + if (i >= 0) { + if (c == '-') { + version[i] = '\0'; + i = -1; + } else if (i < sizeof(version) - 1) + version[i++] = c; + } else if (c == '\n') + break; + } + + ssh_agentfwd_enabled = FALSE; + rdpkt2_state.incoming_sequence = 0; + + vstring[vslen] = 0; + vlog = smalloc(20 + vslen); + vstring[strcspn (vstring, "\r\n")] = '\0'; /* remove end-of-line chars */ + sprintf(vlog, "Server version: %s", vstring); + logevent(vlog); + ssh_detect_bugs(vstring); + sfree(vlog); + + /* + * Server version "1.99" means we can choose whether we use v1 + * or v2 protocol. Choice is based on cfg.sshprot. + */ + if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) { + /* + * This is a v2 server. Begin v2 protocol. + */ + char verstring[80], vlog[100]; + sprintf(verstring, "SSH-2.0-%s", sshver); + SHA_Init(&exhashbase); + /* + * Hash our version string and their version string. + */ + sha_string(&exhashbase, verstring, strlen(verstring)); + sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n")); + sprintf(vlog, "We claim version: %s", verstring); + logevent(vlog); + strcat(verstring, "\n"); + logevent("Using SSH protocol version 2"); + sk_write(s, verstring, strlen(verstring)); + ssh_protocol = ssh2_protocol; + ssh_version = 2; + s_rdpkt = ssh2_rdpkt; + } else { + /* + * This is a v1 server. Begin v1 protocol. + */ + char verstring[80], vlog[100]; + sprintf(verstring, "SSH-%s-%s", + (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"), + sshver); + sprintf(vlog, "We claim version: %s", verstring); + logevent(vlog); + strcat(verstring, "\n"); + logevent("Using SSH protocol version 1"); + sk_write(s, verstring, strlen(verstring)); + ssh_protocol = ssh1_protocol; + ssh_version = 1; + s_rdpkt = ssh1_rdpkt; + } + ssh_state = SSH_STATE_BEFORE_SIZE; + + sfree(vstring); + + crFinish(0); +} + +static void ssh_gotdata(unsigned char *data, int datalen) +{ + crBegin; + + /* + * 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; + if (datalen == 0) + crReturnV; /* more data please */ + ret = do_ssh_init(*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 (s_rdpkt(&data, &datalen) == 0) { + if (ssh_state == SSH_STATE_CLOSED) { + return; + } + ssh_protocol(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_state = SSH_STATE_CLOSED; + if (s) { + sk_close(s); + s = NULL; + } + if (error_msg) { + /* A socket error has occurred. */ + 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_gotdata(data, len); + if (ssh_state == SSH_STATE_CLOSED) { + if (s) { + sk_close(s); + s = NULL; + } + return 0; + } + return 1; +} + +static void ssh_sent(Plug plug, int bufsize) +{ + /* + * 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(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(char *host, int port, char **realhost, int nodelay) +{ + static struct plug_function_table fn_table = { + ssh_closing, + ssh_receive, + ssh_sent, + NULL + }, *fn_table_ptr = &fn_table; + + SockAddr addr; + char *err; +#ifdef FWHACK + char *FWhost; + int FWport; +#endif + + savedhost = smalloc(1 + strlen(host)); + if (!savedhost) + fatalbox("Out of memory"); + strcpy(savedhost, host); + + if (port < 0) + port = 22; /* default ssh port */ + savedport = port; + +#ifdef FWHACK + FWhost = host; + FWport = port; + host = FWSTR; + port = 23; +#endif + + /* + * 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; + +#ifdef FWHACK + *realhost = strdup(FWhost); +#endif + + /* + * Open socket. + */ + { + char buf[200], addrbuf[100]; + sk_getaddr(addr, addrbuf, 100); + sprintf(buf, "Connecting to %.100s port %d", addrbuf, port); + logevent(buf); + } + s = new_connection(addr, *realhost, port, 0, 1, nodelay, &fn_table_ptr); + if ((err = sk_socket_error(s))) { + s = NULL; + return err; + } + +#ifdef FWHACK + sk_write(s, "connect ", 8); + sk_write(s, FWhost, strlen(FWhost)); + { + char buf[20]; + sprintf(buf, " %d\n", FWport); + sk_write(s, buf, strlen(buf)); + } +#endif + + return NULL; +} + +/* + * Throttle or unthrottle the SSH connection. + */ +static void ssh1_throttle(int adjust) +{ + int old_count = ssh1_throttle_count; + ssh1_throttle_count += adjust; + assert(ssh1_throttle_count >= 0); + if (ssh1_throttle_count && !old_count) { + sk_set_frozen(s, 1); + } else if (!ssh1_throttle_count && old_count) { + sk_set_frozen(s, 0); + } +} + +/* + * Throttle or unthrottle _all_ local data streams (for when sends + * on the SSH connection itself back up). + */ +static void ssh_throttle_all(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; + } + } +} + +/* + * Handle the key exchange and user authentication phases. + */ +static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) +{ + int i, j; + static int len; + static unsigned char *rsabuf, *keystr1, *keystr2; + unsigned char cookie[8]; + struct RSAKey servkey, hostkey; + struct MD5Context md5c; + static unsigned long supported_ciphers_mask, supported_auths_mask; + static int tried_publickey, tried_agent; + static int tis_auth_refused, ccard_auth_refused; + static unsigned char session_id[16]; + static int cipher_type; + static char username[100]; + static void *publickey_blob; + int publickey_bloblen; + + crBegin; + + if (!ispkt) + crWaitUntil(ispkt); + + if (pktin.type != SSH1_SMSG_PUBLIC_KEY) { + bombout(("Public key packet not received")); + crReturn(0); + } + + logevent("Received public keys"); + + memcpy(cookie, pktin.body, 8); + + i = makekey(pktin.body + 8, &servkey, &keystr1, 0); + j = makekey(pktin.body + 8 + i, &hostkey, &keystr2, 0); + + /* + * Log the host key fingerprint. + */ + { + char logmsg[80]; + logevent("Host key fingerprint is:"); + strcpy(logmsg, " "); + hostkey.comment = NULL; + rsa_fingerprint(logmsg + strlen(logmsg), + sizeof(logmsg) - strlen(logmsg), &hostkey); + logevent(logmsg); + } + + ssh1_remote_protoflags = GET_32BIT(pktin.body + 8 + i + j); + supported_ciphers_mask = GET_32BIT(pktin.body + 12 + i + j); + supported_auths_mask = GET_32BIT(pktin.body + 16 + i + j); + + ssh1_local_protoflags = + ssh1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED; + ssh1_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); + + for (i = 0; i < 32; i++) + session_key[i] = random_byte(); + + len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes); + + rsabuf = smalloc(len); + if (!rsabuf) + fatalbox("Out of memory"); + + /* + * Verify the host key. + */ + { + /* + * 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(savedhost, savedport, "rsa", keystr, + fingerprint); + sfree(keystr); + } + + for (i = 0; i < 32; i++) { + rsabuf[i] = session_key[i]; + if (i < 16) + rsabuf[i] ^= session_id[i]; + } + + if (hostkey.bytes > servkey.bytes) { + rsaencrypt(rsabuf, 32, &servkey); + rsaencrypt(rsabuf, servkey.bytes, &hostkey); + } else { + rsaencrypt(rsabuf, 32, &hostkey); + rsaencrypt(rsabuf, hostkey.bytes, &servkey); + } + + logevent("Encrypted session key"); + + { + int cipher_chosen = 0, warn = 0; + char *cipher_string = NULL; + 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: cipher_type = SSH_CIPHER_3DES; + cipher_string = "3DES"; break; + case CIPHER_BLOWFISH: cipher_type = SSH_CIPHER_BLOWFISH; + cipher_string = "Blowfish"; break; + case CIPHER_DES: cipher_type = SSH_CIPHER_DES; + cipher_string = "single-DES"; break; + } + if (supported_ciphers_mask & (1 << cipher_type)) + cipher_chosen = 1; + } + } + if (!cipher_chosen) { + if ((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; + } + + 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, ssh1_local_protoflags, PKT_END); + + logevent("Trying to enable encryption..."); + + sfree(rsabuf); + + cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 : + cipher_type == SSH_CIPHER_DES ? &ssh_des : &ssh_3des; + cipher->sesskey(session_key); + + crWaitUntil(ispkt); + + if (pktin.type != SSH1_SMSG_SUCCESS) { + bombout(("Encryption not successfully enabled")); + crReturn(0); + } + + logevent("Successfully started encryption"); + + fflush(stdout); + { + static int pos = 0; + static char c; + if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { + if (ssh_get_line) { + if (!ssh_get_line("login as: ", + username, sizeof(username), FALSE)) { + /* + * get_line failed to get a username. + * Terminate. + */ + logevent("No username provided. Abandoning session."); + ssh_state = SSH_STATE_CLOSED; + crReturn(1); + } + } else { + c_write_str("login as: "); + ssh_send_ok = 1; + 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_str("\b \b"); + pos--; + } + break; + case 21: + case 27: + while (pos > 0) { + c_write_str("\b \b"); + pos--; + } + break; + case 3: + case 4: + cleanup_exit(0); + break; + default: + if (((c >= ' ' && c <= '~') || + ((unsigned char) c >= 160)) + && pos < sizeof(username)-1) { + username[pos++] = c; + c_write(&c, 1); + } + break; + } + } + c_write_str("\r\n"); + username[strcspn(username, "\n\r")] = '\0'; + } + } else { + strncpy(username, cfg.username, 99); + username[99] = '\0'; + } + + send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END); + { + char userlog[22 + sizeof(username)]; + sprintf(userlog, "Sent username \"%s\"", username); + logevent(userlog); + if (flags & FLAG_INTERACTIVE && + (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) { + strcat(userlog, "\r\n"); + c_write_str(userlog); + } + } + } + + crWaitUntil(ispkt); + + if ((ssh_remote_bugs & BUG_CHOKES_ON_RSA)) { + /* We must not attempt PK auth. Pretend we've already tried it. */ + tried_publickey = tried_agent = 1; + } else { + tried_publickey = tried_agent = 0; + } + tis_auth_refused = 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, &publickey_blob, &publickey_bloblen)) + publickey_blob = NULL; + } else + publickey_blob = NULL; + + while (pktin.type == SSH1_SMSG_FAILURE) { + static char password[100]; + static char prompt[200]; + static int pos; + static char c; + static int pwpkt_type; + pwpkt_type = SSH1_CMSG_AUTH_PASSWORD; + + if (agent_exists() && !tried_agent) { + /* + * 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; + + tried_agent = 1; + logevent("Pageant is running. Requesting keys."); + + /* Request the keys held by the agent. */ + PUT_32BIT(request, 1); + request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES; + agent_query(request, 5, &r, &responselen); + response = (unsigned char *) r; + if (response && responselen >= 5 && + response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) { + p = response + 5; + nkeys = GET_32BIT(p); + p += 4; + { + char buf[64]; + sprintf(buf, "Pageant has %d SSH1 keys", nkeys); + logevent(buf); + } + for (i = 0; i < nkeys; i++) { + static struct RSAKey key; + static Bignum challenge; + static char *commentp; + static int commentlen; + + { + char buf[64]; + sprintf(buf, "Trying Pageant key #%d", i); + logevent(buf); + } + if (publickey_blob && + !memcmp(p, publickey_blob, publickey_bloblen)) { + logevent("This key matches configured key file"); + tried_publickey = 1; + } + p += 4; + p += ssh1_read_bignum(p, &key.exponent); + p += ssh1_read_bignum(p, &key.modulus); + commentlen = GET_32BIT(p); + p += 4; + commentp = p; + p += commentlen; + 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; + void *vret; + 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 = smalloc(4 + len); + PUT_32BIT(agentreq, len); + q = agentreq + 4; + *q++ = SSH1_AGENTC_RSA_CHALLENGE; + PUT_32BIT(q, 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, &vret, &retlen); + ret = vret; + sfree(agentreq); + if (ret) { + if (ret[4] == SSH1_AGENT_RSA_RESPONSE) { + logevent("Sending Pageant's response"); + send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE, + PKT_DATA, ret + 5, 16, + PKT_END); + sfree(ret); + crWaitUntil(ispkt); + if (pktin.type == SSH1_SMSG_SUCCESS) { + logevent + ("Pageant's response accepted"); + if (flags & FLAG_VERBOSE) { + c_write_str + ("Authenticated using RSA key \""); + c_write(commentp, commentlen); + c_write_str("\" from agent\r\n"); + } + 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(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 (cfg.try_tis_auth && + (supported_auths_mask & (1 << SSH1_AUTH_TIS)) && + !tis_auth_refused) { + pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE; + logevent("Requested TIS authentication"); + send_packet(SSH1_CMSG_AUTH_TIS, PKT_END); + crWaitUntil(ispkt); + if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) { + logevent("TIS authentication declined"); + if (flags & FLAG_INTERACTIVE) + c_write_str("TIS authentication refused.\r\n"); + tis_auth_refused = 1; + continue; + } else { + int challengelen = ((pktin.body[0] << 24) | + (pktin.body[1] << 16) | + (pktin.body[2] << 8) | + (pktin.body[3])); + logevent("Received TIS challenge"); + if (challengelen > sizeof(prompt) - 1) + challengelen = sizeof(prompt) - 1; /* prevent overrun */ + memcpy(prompt, pktin.body + 4, challengelen); + /* Prompt heuristic comes from OpenSSH */ + strncpy(prompt + challengelen, + memchr(prompt, '\n', challengelen) ? + "": "\r\nResponse: ", + (sizeof prompt) - challengelen); + prompt[(sizeof prompt) - 1] = '\0'; + } + } + if (cfg.try_tis_auth && + (supported_auths_mask & (1 << SSH1_AUTH_CCARD)) && + !ccard_auth_refused) { + pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE; + logevent("Requested CryptoCard authentication"); + send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END); + crWaitUntil(ispkt); + if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) { + logevent("CryptoCard authentication declined"); + c_write_str("CryptoCard authentication refused.\r\n"); + ccard_auth_refused = 1; + continue; + } else { + int challengelen = ((pktin.body[0] << 24) | + (pktin.body[1] << 16) | + (pktin.body[2] << 8) | + (pktin.body[3])); + logevent("Received CryptoCard challenge"); + if (challengelen > sizeof(prompt) - 1) + challengelen = sizeof(prompt) - 1; /* prevent overrun */ + memcpy(prompt, pktin.body + 4, challengelen); + strncpy(prompt + challengelen, + memchr(prompt, '\n', challengelen) ? + "" : "\r\nResponse: ", + sizeof(prompt) - challengelen); + prompt[sizeof(prompt) - 1] = '\0'; + } + } + if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) { + sprintf(prompt, "%.90s@%.90s's password: ", + username, savedhost); + } + if (pwpkt_type == SSH1_CMSG_AUTH_RSA) { + char *comment = NULL; + if (flags & FLAG_VERBOSE) + c_write_str("Trying public key authentication.\r\n"); + if (!rsakey_encrypted(cfg.keyfile, &comment)) { + if (flags & FLAG_VERBOSE) + c_write_str("No passphrase required.\r\n"); + goto tryauth; + } + sprintf(prompt, "Passphrase for key \"%.100s\": ", comment); + sfree(comment); + } + + /* + * 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(prompt, password, sizeof(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(SSH1_MSG_DISCONNECT, + PKT_STR, "No more passwords available to try", + PKT_END); + 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. */ + c_write_untrusted(prompt, strlen(prompt)); + pos = 0; + ssh_send_ok = 1; + 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: + cleanup_exit(0); + break; + default: + if (pos < sizeof(password)-1) + password[pos++] = c; + break; + } + } + c_write_str("\r\n"); + } + + 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_str("Couldn't load private key from "); + c_write_str(cfg.keyfile); + c_write_str(".\r\n"); + continue; /* go and try password */ + } + if (i == -1) { + c_write_str("Wrong passphrase.\r\n"); + tried_publickey = 0; + continue; /* try again */ + } + + /* + * 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) { + c_write_str("Server refused our public key.\r\n"); + continue; /* go and try password */ + } + if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) { + bombout(("Bizarre response to offer of public key")); + crReturn(0); + } + ssh1_read_bignum(pktin.body, &challenge); + response = rsadecrypt(challenge, &pubkey); + freebn(pubkey.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, 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_str + ("Failed to authenticate with our public key.\r\n"); + continue; /* go and try password */ + } else if (pktin.type != SSH1_SMSG_SUCCESS) { + bombout( + ("Bizarre response to RSA authentication response")); + crReturn(0); + } + + break; /* we're through! */ + } else { + if (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(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(pwpkt_type, PKT_STR, password, + PKT_END); + else { + for (j = 0; j < i; j++) { + do { + randomstr[j] = random_byte(); + } while (randomstr[j] == '\0'); + } + randomstr[i] = '\0'; + defer_packet(SSH1_MSG_IGNORE, + PKT_STR, randomstr, PKT_END); + } + } + logevent("Sending password with camouflage packets"); + ssh_pkt_defersend(); + } + 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 *s; + int len; + + len = strlen(password); + if (len < sizeof(string)) { + s = string; + strcpy(string, password); + len++; /* cover the zero byte */ + while (len < sizeof(string)) { + string[len++] = (char) random_byte(); + } + } else { + s = password; + } + logevent("Sending length-padded password"); + send_packet(pwpkt_type, PKT_INT, len, + PKT_DATA, s, 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(password); + logevent("Sending unpadded password"); + send_packet(pwpkt_type, PKT_INT, len, + PKT_DATA, password, len, PKT_END); + } + } else { + send_packet(pwpkt_type, PKT_STR, password, PKT_END); + } + } + logevent("Sent password"); + memset(password, 0, strlen(password)); + crWaitUntil(ispkt); + if (pktin.type == SSH1_SMSG_FAILURE) { + if (flags & FLAG_VERBOSE) + c_write_str("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) { + bombout(("Strange packet received, type %d", pktin.type)); + crReturn(0); + } + } + + logevent("Authentication successful"); + + crFinish(1); +} + +void sshfwd_close(struct ssh_channel *c) +{ + 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 (c->remoteid != -1) { + if (ssh_version == 1) { + send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, + PKT_END); + } else { + ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } + } + c->closes = 1; + 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) +{ + if (ssh_version == 1) { + send_packet(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) +{ + if (ssh_version == 1) { + if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) { + c->v.v1.throttling = 0; + ssh1_throttle(-1); + } + } else { + ssh2_set_window(c, OUR_V2_WINSIZE - bufsize); + } +} + +static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) +{ + crBegin; + + random_init(); + + while (!do_ssh1_login(in, inlen, ispkt)) { + crReturnV; + } + if (ssh_state == SSH_STATE_CLOSED) + crReturnV; + + if (cfg.agentfwd && agent_exists()) { + logevent("Requesting agent forwarding"); + send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END); + do { + crReturnV; + } while (!ispkt); + if (pktin.type != SSH1_SMSG_SUCCESS + && pktin.type != SSH1_SMSG_FAILURE) { + bombout(("Protocol confusion")); + crReturnV; + } else if (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 (ssh1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) { + send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING, + PKT_STR, proto, PKT_STR, data, + PKT_INT, 0, PKT_END); + } else { + send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING, + PKT_STR, proto, PKT_STR, data, PKT_END); + } + do { + crReturnV; + } while (!ispkt); + if (pktin.type != SSH1_SMSG_SUCCESS + && pktin.type != SSH1_SMSG_FAILURE) { + bombout(("Protocol confusion")); + crReturnV; + } else if (pktin.type == SSH1_SMSG_FAILURE) { + logevent("X11 forwarding refused"); + } else { + logevent("X11 forwarding enabled"); + ssh_X11_fwd_enabled = TRUE; + } + } + + { + char type, *e; + int n; + int sport,dport; + char sports[256], dports[256], host[256]; + char buf[1024]; + + ssh_rportfwds = newtree234(ssh_rportcmp_ssh1); + /* Add port forwardings. */ + e = cfg.portfwd; + while (*e) { + type = *e++; + n = 0; + while (*e && *e != '\t') + sports[n++] = *e++; + sports[n] = 0; + if (*e == '\t') + e++; + n = 0; + while (*e && *e != ':') + host[n++] = *e++; + host[n] = 0; + if (*e == ':') + e++; + n = 0; + while (*e) + dports[n++] = *e++; + dports[n] = 0; + e++; + dport = atoi(dports); + sport = atoi(sports); + if (sport && dport) { + if (type == 'L') { + pfd_addforward(host, dport, sport); + sprintf(buf, "Local port %d forwarding to %s:%d", + sport, host, dport); + 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 %d forward to %s:%d", + sport, host, dport); + logevent(buf); + send_packet(SSH1_CMSG_PORT_FORWARD_REQUEST, + PKT_INT, sport, + PKT_STR, host, + PKT_INT, dport, + PKT_END); + } + } + } + } + } + + 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) { + bombout(("Protocol confusion")); + crReturnV; + } else if (pktin.type == SSH1_SMSG_FAILURE) { + c_write_str("Server refused to allocate pty\r\n"); + ssh_editing = ssh_echoing = 1; + } + logevent("Allocated pty"); + } else { + ssh_editing = ssh_echoing = 1; + } + + if (cfg.compression) { + send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END); + do { + crReturnV; + } while (!ispkt); + if (pktin.type != SSH1_SMSG_SUCCESS + && pktin.type != SSH1_SMSG_FAILURE) { + bombout(("Protocol confusion")); + crReturnV; + } else if (pktin.type == SSH1_SMSG_FAILURE) { + c_write_str("Server refused to compress\r\n"); + } + logevent("Started compression"); + ssh1_compressing = TRUE; + zlib_compress_init(); + zlib_decompress_init(); + } + + /* + * 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(SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END); + else + send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END); + logevent("Started session"); + } + + ssh_state = SSH_STATE_SESSION; + if (size_needed) + ssh_size(); + if (eof_needed) + ssh_special(TS_EOF); + + 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 == 17 || pktin.type == 18) { - long len = 0; - for (i = 0; i < 4; i++) - len = (len << 8) + pktin.body[i]; - c_write(pktin.body+4, len); - } else if (pktin.type == 1) { - /* SSH_MSG_DISCONNECT: do nothing */ - } else if (pktin.type == 14) { - /* SSH_MSG_SUCCESS: may be from EXEC_SHELL on some servers */ - } else if (pktin.type == 15) { - /* SSH_MSG_FAILURE: may be from EXEC_SHELL on some servers + if (pktin.type == SSH1_SMSG_STDOUT_DATA || + pktin.type == SSH1_SMSG_STDERR_DATA) { + long len = GET_32BIT(pktin.body); + int bufsize = + from_backend(pktin.type == SSH1_SMSG_STDERR_DATA, + pktin.body + 4, len); + if (!ssh1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) { + ssh1_stdout_throttling = 1; + ssh1_throttle(+1); + } + } else if (pktin.type == SSH1_MSG_DISCONNECT) { + ssh_state = SSH_STATE_CLOSED; + logevent("Received disconnect request"); + crReturnV; + } else if (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(SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(pktin.body), PKT_END); + logevent("Rejected X11 connect request"); + } else { + c = smalloc(sizeof(struct ssh_channel)); + + if (x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL) { + logevent("opening X11 forward connection failed"); + sfree(c); + send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(pktin.body), + PKT_END); + } else { + logevent + ("opening X11 forward connection succeeded"); + c->remoteid = GET_32BIT(pktin.body); + c->localid = alloc_channel_id(); + c->closes = 0; + c->v.v1.throttling = 0; + c->type = CHAN_X11; /* identify channel type */ + add234(ssh_channels, c); + send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, + PKT_INT, c->remoteid, PKT_INT, + c->localid, PKT_END); + logevent("Opened X11 forward channel"); + } + } + } else if (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(SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(pktin.body), PKT_END); + } else { + c = smalloc(sizeof(struct ssh_channel)); + c->remoteid = GET_32BIT(pktin.body); + c->localid = alloc_channel_id(); + 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(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, + PKT_INT, c->remoteid, PKT_INT, c->localid, + PKT_END); + } + } else if (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)); + + hostsize = GET_32BIT(pktin.body+4); + for(h = host, p = 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(SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(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(SSH1_MSG_CHANNEL_OPEN_FAILURE, + PKT_INT, GET_32BIT(pktin.body), + PKT_END); + } else { + c->remoteid = GET_32BIT(pktin.body); + c->localid = alloc_channel_id(); + c->closes = 0; + c->v.v1.throttling = 0; + c->type = CHAN_SOCKDATA; /* identify channel type */ + add234(ssh_channels, c); + send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION, + PKT_INT, c->remoteid, PKT_INT, + c->localid, PKT_END); + logevent("Forwarded port opened successfully"); + } + } + + } else if (pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) { + unsigned int remoteid = GET_32BIT(pktin.body); + unsigned int localid = GET_32BIT(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(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, + PKT_END); + } + + } else if (pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) { + unsigned int remoteid = GET_32BIT(pktin.body); + unsigned int localid = GET_32BIT(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 (pktin.type == SSH1_MSG_CHANNEL_CLOSE || + pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) { + /* Remote side closes a channel. */ + unsigned i = GET_32BIT(pktin.body); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (c) { + int closetype; + closetype = + (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2); + if (!(c->closes & closetype)) + send_packet(pktin.type, PKT_INT, c->remoteid, + PKT_END); + 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; + if (c->closes == 3) { + del234(ssh_channels, c); + sfree(c); + } + } + } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) { + /* Data sent down one of our channels. */ + int i = GET_32BIT(pktin.body); + int len = GET_32BIT(pktin.body + 4); + unsigned char *p = 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(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(+1); + } + } + } else if (pktin.type == SSH1_SMSG_SUCCESS) { + /* may be from EXEC_SHELL on some servers */ + } else if (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 == 20) { - /* EXITSTATUS */ - s_wrpkt_start(33, 0); - s_wrpkt(); + } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) { + char buf[100]; + ssh_exitcode = GET_32BIT(pktin.body); + sprintf(buf, "Server sent command exit status %d", + ssh_exitcode); + logevent(buf); + send_packet(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 { + bombout(("Strange packet received: type %d", pktin.type)); + crReturnV; + } + } else { + while (inlen > 0) { + int len = min(inlen, 512); + send_packet(SSH1_CMSG_STDIN_DATA, + PKT_INT, len, PKT_DATA, in, len, PKT_END); + in += len; + inlen -= len; + } + } + } + + crFinishV; +} + +/* + * Utility routine for decoding comma-separated strings in KEXINIT. + */ +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 */ + } +} + +/* + * SSH2 key creation method. + */ +static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr, + char *keyspace) +{ + SHA_State s; + /* First 20 bytes. */ + SHA_Init(&s); + sha_mpint(&s, K); + SHA_Bytes(&s, H, 20); + SHA_Bytes(&s, &chr, 1); + SHA_Bytes(&s, sessid, 20); + SHA_Final(&s, keyspace); + /* Next 20 bytes. */ + SHA_Init(&s); + sha_mpint(&s, K); + SHA_Bytes(&s, H, 20); + SHA_Bytes(&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, j, len, nbits, pbits, warn; + static char *str; + static Bignum p, g, e, f, K; + static int kex_init_value, kex_reply_value; + static const struct ssh_mac **maclist; + static int nmacs; + static const struct ssh2_cipher *cscipher_tobe = NULL; + static const struct ssh2_cipher *sccipher_tobe = NULL; + static const struct ssh_mac *csmac_tobe = NULL; + static const struct ssh_mac *scmac_tobe = NULL; + static const struct ssh_compress *cscomp_tobe = NULL; + static const struct ssh_compress *sccomp_tobe = NULL; + static char *hostkeydata, *sigdata, *keystr, *fingerprint; + static int hostkeylen, siglen; + static void *hkey; /* actual host key */ + static unsigned char exchange_hash[20]; + static unsigned char keyspace[40]; + static int n_preferred_ciphers; + static const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX]; + static const struct ssh_compress *preferred_comp; + static int cipherstr_started; + static int first_kex; + + crBegin; + random_init(); + first_kex = 1; + + /* + * Set up the preferred ciphers. (NULL => warn below here) + */ + n_preferred_ciphers = 0; + for (i = 0; i < CIPHER_MAX; i++) { + switch (cfg.ssh_cipherlist[i]) { + case CIPHER_BLOWFISH: + preferred_ciphers[n_preferred_ciphers] = &ssh2_blowfish; + n_preferred_ciphers++; + break; + case CIPHER_DES: + if (cfg.ssh2_des_cbc) { + preferred_ciphers[n_preferred_ciphers] = &ssh2_des; + n_preferred_ciphers++; + } + break; + case CIPHER_3DES: + preferred_ciphers[n_preferred_ciphers] = &ssh2_3des; + n_preferred_ciphers++; + break; + case CIPHER_AES: + preferred_ciphers[n_preferred_ciphers] = &ssh2_aes; + n_preferred_ciphers++; + break; + case CIPHER_WARN: + /* Flag for later. Don't bother if it's the last in + * the list. */ + if (i < CIPHER_MAX - 1) { + preferred_ciphers[n_preferred_ciphers] = NULL; + n_preferred_ciphers++; + } + break; + } + } + + /* + * Set up preferred compression. + */ + if (cfg.compression) + preferred_comp = &ssh_zlib; + else + preferred_comp = &ssh_comp_none; + + /* + * Be prepared to work around the buggy MAC problem. + */ + if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC)) + maclist = buggymacs, nmacs = lenof(buggymacs); + else + maclist = macs, nmacs = lenof(macs); + + begin_key_exchange: + /* + * Construct and send our key exchange packet. + */ + 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(); + cipherstr_started = 0; + for (i = 0; i < n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = preferred_ciphers[i]; + if (!c) continue; /* warning flag */ + for (j = 0; j < c->nciphers; j++) { + if (cipherstr_started) + ssh2_pkt_addstring_str(","); + ssh2_pkt_addstring_str(c->list[j]->name); + cipherstr_started = 1; + } + } + /* List server->client encryption algorithms. */ + ssh2_pkt_addstring_start(); + cipherstr_started = 0; + for (i = 0; i < n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = preferred_ciphers[i]; + if (!c) continue; /* warning flag */ + for (j = 0; j < c->nciphers; j++) { + if (cipherstr_started) + ssh2_pkt_addstring_str(","); + ssh2_pkt_addstring_str(c->list[j]->name); + cipherstr_started = 1; + } + } + /* List client->server MAC algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < nmacs; i++) { + ssh2_pkt_addstring_str(maclist[i]->name); + if (i < nmacs - 1) + ssh2_pkt_addstring_str(","); + } + /* List server->client MAC algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < nmacs; i++) { + ssh2_pkt_addstring_str(maclist[i]->name); + if (i < nmacs - 1) + ssh2_pkt_addstring_str(","); + } + /* List client->server compression algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < lenof(compressions) + 1; i++) { + const struct ssh_compress *c = + i == 0 ? preferred_comp : compressions[i - 1]; + ssh2_pkt_addstring_str(c->name); + if (i < lenof(compressions)) + ssh2_pkt_addstring_str(","); + } + /* List server->client compression algorithms. */ + ssh2_pkt_addstring_start(); + for (i = 0; i < lenof(compressions) + 1; i++) { + const struct ssh_compress *c = + i == 0 ? preferred_comp : compressions[i - 1]; + ssh2_pkt_addstring_str(c->name); + if (i < lenof(compressions)) + 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); + + exhash = exhashbase; + 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); + + /* + * Now examine the other side's KEXINIT to see what we're up + * to. + */ + if (pktin.type != SSH2_MSG_KEXINIT) { + bombout(("expected key exchange packet from server")); + crReturn(0); + } + 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 */ + warn = 0; + for (i = 0; i < n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = preferred_ciphers[i]; + if (!c) { + warn = 1; + } else { + for (j = 0; j < c->nciphers; j++) { + if (in_commasep_string(c->list[j]->name, str, len)) { + cscipher_tobe = c->list[j]; + break; + } + } + } + if (cscipher_tobe) { + if (warn) + askcipher(cscipher_tobe->name, 1); + break; + } + } + if (!cscipher_tobe) { + bombout(("Couldn't agree a client-to-server cipher (available: %s)", str)); + crReturn(0); + } + + ssh2_pkt_getstring(&str, &len); /* server->client cipher */ + warn = 0; + for (i = 0; i < n_preferred_ciphers; i++) { + const struct ssh2_ciphers *c = preferred_ciphers[i]; + if (!c) { + warn = 1; + } else { + for (j = 0; j < c->nciphers; j++) { + if (in_commasep_string(c->list[j]->name, str, len)) { + sccipher_tobe = c->list[j]; + break; + } + } + } + if (sccipher_tobe) { + if (warn) + askcipher(sccipher_tobe->name, 2); + break; + } + } + if (!sccipher_tobe) { + bombout(("Couldn't agree a server-to-client cipher (available: %s)", str)); + crReturn(0); + } + + ssh2_pkt_getstring(&str, &len); /* client->server mac */ + for (i = 0; i < nmacs; i++) { + if (in_commasep_string(maclist[i]->name, str, len)) { + csmac_tobe = maclist[i]; + break; + } + } + ssh2_pkt_getstring(&str, &len); /* server->client mac */ + for (i = 0; i < nmacs; i++) { + if (in_commasep_string(maclist[i]->name, str, len)) { + scmac_tobe = maclist[i]; + break; + } + } + ssh2_pkt_getstring(&str, &len); /* client->server compression */ + for (i = 0; i < lenof(compressions) + 1; i++) { + const struct ssh_compress *c = + i == 0 ? preferred_comp : compressions[i - 1]; + if (in_commasep_string(c->name, str, len)) { + cscomp_tobe = c; + break; + } + } + ssh2_pkt_getstring(&str, &len); /* server->client compression */ + for (i = 0; i < lenof(compressions) + 1; i++) { + const struct ssh_compress *c = + i == 0 ? preferred_comp : compressions[i - 1]; + if (in_commasep_string(c->name, str, len)) { + sccomp_tobe = c; + 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 = cscipher_tobe->keylen; + scbits = sccipher_tobe->keylen; + 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 (nbits > 160) + nbits = 160; + + /* + * If we're doing Diffie-Hellman group exchange, start by + * requesting a group. + */ + if (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. + */ + pbits = 512 << ((nbits - 1) / 64); + ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST); + ssh2_pkt_adduint32(pbits); + ssh2_pkt_send(); + + crWaitUntil(ispkt); + if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) { + bombout(("expected key exchange group packet from server")); + crReturn(0); + } + p = ssh2_pkt_getmp(); + g = ssh2_pkt_getmp(); + dh_setup_group(p, g); + kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT; + kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY; + } else { + ssh_pkt_ctx |= SSH2_PKTCTX_DHGROUP1; + dh_setup_group1(); + kex_init_value = SSH2_MSG_KEXDH_INIT; + kex_reply_value = SSH2_MSG_KEXDH_REPLY; + } + + logevent("Doing Diffie-Hellman key exchange"); + /* + * Now generate and send e for Diffie-Hellman. + */ + e = dh_create_e(nbits * 2); + ssh2_pkt_init(kex_init_value); + ssh2_pkt_addmp(e); + ssh2_pkt_send(); + + crWaitUntil(ispkt); + if (pktin.type != 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); + + K = dh_find_K(f); + + sha_string(&exhash, hostkeydata, hostkeylen); + if (kex == &ssh_diffiehellman_gex) { + sha_uint32(&exhash, pbits); + sha_mpint(&exhash, p); + sha_mpint(&exhash, g); + } + sha_mpint(&exhash, e); + sha_mpint(&exhash, f); + sha_mpint(&exhash, K); + SHA_Final(&exhash, exchange_hash); + + dh_cleanup(); + +#if 0 + debug(("Exchange hash is:\n")); + dmemdump(exchange_hash, 20); +#endif + + hkey = hostkey->newkey(hostkeydata, hostkeylen); + if (!hkey || + !hostkey->verifysig(hkey, sigdata, siglen, 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(hkey); + fingerprint = hostkey->fingerprint(hkey); + verify_ssh_host_key(savedhost, savedport, hostkey->keytype, + keystr, fingerprint); + if (first_kex) { /* don't bother logging this in rekeys */ + logevent("Host key fingerprint is:"); + logevent(fingerprint); + } + sfree(fingerprint); + sfree(keystr); + hostkey->freekey(hkey); + + /* + * Send SSH2_MSG_NEWKEYS. + */ + ssh2_pkt_init(SSH2_MSG_NEWKEYS); + ssh2_pkt_send(); + + /* + * Expect SSH2_MSG_NEWKEYS from server. + */ + crWaitUntil(ispkt); + if (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; + cscomp->compress_init(); + sccomp->decompress_init(); + /* + * Set IVs after keys. Here we use the exchange hash from the + * _first_ key exchange. + */ + if (first_kex) + memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash)); + ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace); + cscipher->setcskey(keyspace); + ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace); + sccipher->setsckey(keyspace); + ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace); + cscipher->setcsiv(keyspace); + ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace); + sccipher->setsciv(keyspace); + ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace); + csmac->setcskey(keyspace); + ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace); + scmac->setsckey(keyspace); + + /* + * 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. + */ + if (!first_kex) { + crReturn(0); + } + first_kex = 0; + + /* + * Now we're encrypting. Begin returning 1 to the protocol main + * function so that other things can run on top of the + * transport. If we ever see a KEXINIT, we must go back to the + * start. + */ + while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) { + crReturn(1); + } + logevent("Server initiated key re-exchange"); + goto begin_key_exchange; + + crFinish(1); +} + +/* + * Add data to an SSH2 channel output buffer. + */ +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) +{ + 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(SSH2_MSG_CHANNEL_DATA); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(data, len); + ssh2_pkt_send(); + 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) +{ + /* + * 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(SSH2_MSG_CHANNEL_WINDOW_ADJUST); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_adduint32(newwin - c->v.v2.locwindow); + ssh2_pkt_send(); + 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 enum { + AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE, + AUTH_PASSWORD, + AUTH_KEYBOARD_INTERACTIVE + } method; + static 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; + static int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter; + static int tried_pubkey_config, tried_agent, tried_keyb_inter; + static int kbd_inter_running; + static int we_are_in; + static int num_prompts, echo; + static char username[100]; + static int got_username; + static char pwprompt[200]; + static char password[100]; + static void *publickey_blob; + static int publickey_bloblen; + + crBegin; + + /* + * 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) { + 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 are sent back to the + * beginning to try another username. (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! + */ + username[0] = '\0'; + got_username = FALSE; + do { + static int pos; + static char c; + + /* + * Get a username. + */ + pos = 0; + if (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) { + if (!ssh_get_line("login as: ", + username, sizeof(username), FALSE)) { + /* + * get_line failed to get a username. + * Terminate. + */ + logevent("No username provided. Abandoning session."); + ssh_state = SSH_STATE_CLOSED; + crReturnV; + } + } else { + c_write_str("login as: "); + ssh_send_ok = 1; + 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_str("\b \b"); + pos--; + } + break; + case 21: + case 27: + while (pos > 0) { + c_write_str("\b \b"); + pos--; + } + break; + case 3: + case 4: + cleanup_exit(0); + break; + default: + if (((c >= ' ' && c <= '~') || + ((unsigned char) c >= 160)) + && pos < sizeof(username)-1) { + username[pos++] = c; + c_write(&c, 1); + } + break; + } + } + } + c_write_str("\r\n"); + username[strcspn(username, "\n\r")] = '\0'; + } else { + char stuff[200]; + strncpy(username, cfg.username, 99); + username[99] = '\0'; + if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) { + sprintf(stuff, "Using username \"%s\".\r\n", username); + c_write_str(stuff); + } + } + 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(SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(username); + ssh2_pkt_addstring("ssh-connection"); /* service requested */ + ssh2_pkt_addstring("none"); /* method */ + ssh2_pkt_send(); + type = AUTH_TYPE_NONE; + gotit = FALSE; + we_are_in = FALSE; + + tried_pubkey_config = FALSE; + tried_agent = FALSE; + tried_keyb_inter = FALSE; + kbd_inter_running = FALSE; + /* Load the pub half of cfg.keyfile so we notice if it's in Pageant */ + if (*cfg.keyfile) { + publickey_blob = ssh2_userkey_loadpub(cfg.keyfile, NULL, + &publickey_bloblen); + } else + publickey_blob = NULL; + + while (1) { + /* + * Wait for the result of the last authentication request. + */ + if (!gotit) + crWaitUntilV(ispkt); + while (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(&banner, &size); + if (banner) + c_write_untrusted(banner, size); + } + crWaitUntilV(ispkt); + } + if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) { + logevent("Access granted"); + we_are_in = TRUE; + break; + } + + if (kbd_inter_running && + pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) { + /* + * This is a further prompt in keyboard-interactive + * authentication. Do nothing. + */ + } else if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) { + bombout(("Strange packet received during authentication: type %d", + pktin.type)); + crReturnV; + } + + 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 (pktin.type == SSH2_MSG_USERAUTH_FAILURE) { + char *methods; + int methlen; + ssh2_pkt_getstring(&methods, &methlen); + kbd_inter_running = FALSE; + if (!ssh2_pkt_getbool()) { + /* + * 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 (type == AUTH_TYPE_NONE) { + /* do nothing */ + } else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD || + type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) { + if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD) + c_write_str("Server refused our key\r\n"); + logevent("Server refused public key"); + } else if (type == AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) { + /* server declined keyboard-interactive; ignore */ + } else { + c_write_str("Access denied\r\n"); + logevent("Access denied"); + if (type == AUTH_TYPE_PASSWORD) { + we_are_in = FALSE; + break; + } + } + } else { + c_write_str("Further authentication required\r\n"); + logevent("Further authentication required"); + } + + can_pubkey = + in_commasep_string("publickey", methods, methlen); + can_passwd = + in_commasep_string("password", methods, methlen); + can_keyb_inter = cfg.try_ki_auth && + in_commasep_string("keyboard-interactive", methods, methlen); + } + + method = 0; + ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK; + + if (!method && can_pubkey && agent_exists() && !tried_agent) { + /* + * Attempt public-key authentication using Pageant. + */ + static unsigned char request[5], *response, *p; + static int responselen; + static int i, nkeys; + static int authed = FALSE; + void *r; + + ssh_pkt_ctx |= SSH2_PKTCTX_PUBLICKEY; + + tried_agent = TRUE; + + logevent("Pageant is running. Requesting keys."); + + /* Request the keys held by the agent. */ + PUT_32BIT(request, 1); + request[4] = SSH2_AGENTC_REQUEST_IDENTITIES; + agent_query(request, 5, &r, &responselen); + response = (unsigned char *) r; + if (response && responselen >= 5 && + response[4] == SSH2_AGENT_IDENTITIES_ANSWER) { + p = response + 5; + nkeys = GET_32BIT(p); + p += 4; + { + char buf[64]; + sprintf(buf, "Pageant has %d SSH2 keys", nkeys); + logevent(buf); + } + for (i = 0; i < nkeys; i++) { + static char *pkblob, *alg, *commentp; + static int pklen, alglen, commentlen; + static int siglen, retlen, len; + static char *q, *agentreq, *ret; + void *vret; + + { + char buf[64]; + sprintf(buf, "Trying Pageant key #%d", i); + logevent(buf); + } + pklen = GET_32BIT(p); + p += 4; + if (publickey_blob && + pklen == publickey_bloblen && + !memcmp(p, publickey_blob, publickey_bloblen)) { + logevent("This key matches configured key file"); + tried_pubkey_config = 1; + } + pkblob = p; + p += pklen; + alglen = GET_32BIT(pkblob); + alg = pkblob + 4; + commentlen = GET_32BIT(p); + p += 4; + commentp = p; + p += commentlen; + ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(username); + ssh2_pkt_addstring("ssh-connection"); /* service requested */ + ssh2_pkt_addstring("publickey"); /* method */ + ssh2_pkt_addbool(FALSE); /* no signature included */ + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(alg, alglen); + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(pkblob, pklen); + ssh2_pkt_send(); + + crWaitUntilV(ispkt); + if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) { + logevent("Key refused"); + continue; + } + + if (flags & FLAG_VERBOSE) { + c_write_str + ("Authenticating with public key \""); + c_write(commentp, commentlen); + c_write_str("\" from agent\r\n"); + } + + /* + * Server is willing to accept the key. + * Construct a SIGN_REQUEST. + */ + ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(username); + ssh2_pkt_addstring("ssh-connection"); /* service requested */ + ssh2_pkt_addstring("publickey"); /* method */ + ssh2_pkt_addbool(TRUE); + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(alg, alglen); + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(pkblob, pklen); + + siglen = pktout.length - 5 + 4 + 20; + len = 1; /* message type */ + len += 4 + pklen; /* key blob */ + len += 4 + siglen; /* data to sign */ + len += 4; /* flags */ + agentreq = smalloc(4 + len); + PUT_32BIT(agentreq, len); + q = agentreq + 4; + *q++ = SSH2_AGENTC_SIGN_REQUEST; + PUT_32BIT(q, pklen); + q += 4; + memcpy(q, pkblob, pklen); + q += pklen; + PUT_32BIT(q, siglen); + q += 4; + /* Now the data to be signed... */ + PUT_32BIT(q, 20); + q += 4; + memcpy(q, ssh2_session_id, 20); + q += 20; + memcpy(q, pktout.data + 5, pktout.length - 5); + q += pktout.length - 5; + /* And finally the (zero) flags word. */ + PUT_32BIT(q, 0); + agent_query(agentreq, len + 4, &vret, &retlen); + ret = vret; + sfree(agentreq); + if (ret) { + if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) { + logevent("Sending Pageant's response"); + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(ret + 9, + GET_32BIT(ret + + 5)); + ssh2_pkt_send(); + authed = TRUE; + break; + } else { + logevent + ("Pageant failed to answer challenge"); + sfree(ret); + } + } + } + if (authed) + continue; + } + } + + if (!method && can_pubkey && *cfg.keyfile + && !tried_pubkey_config) { + unsigned char *pub_blob; + char *algorithm, *comment; + int pub_blob_len; + + tried_pubkey_config = TRUE; + + 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(SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(username); + ssh2_pkt_addstring("ssh-connection"); /* service requested */ + ssh2_pkt_addstring("publickey"); /* method */ + ssh2_pkt_addbool(FALSE); /* no signature included */ + ssh2_pkt_addstring(algorithm); + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(pub_blob, pub_blob_len); + ssh2_pkt_send(); + logevent("Offered public key"); /* FIXME */ + + crWaitUntilV(ispkt); + if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) { + gotit = TRUE; + type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD; + continue; /* key refused; give up on it */ + } + + logevent("Offer of public key accepted"); + /* + * Actually attempt a serious authentication using + * the key. + */ + if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) { + sprintf(pwprompt, + "Passphrase for key \"%.100s\": ", + comment); + need_pw = TRUE; + } else { + need_pw = FALSE; + } + c_write_str("Authenticating with public key \""); + c_write_str(comment); + c_write_str("\"\r\n"); + method = AUTH_PUBLICKEY_FILE; + } + } + + if (!method && can_keyb_inter && !tried_keyb_inter) { + method = AUTH_KEYBOARD_INTERACTIVE; + type = AUTH_TYPE_KEYBOARD_INTERACTIVE; + tried_keyb_inter = TRUE; + + ssh_pkt_ctx |= SSH2_PKTCTX_KBDINTER; + + ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(username); + ssh2_pkt_addstring("ssh-connection"); /* service requested */ + ssh2_pkt_addstring("keyboard-interactive"); /* method */ + ssh2_pkt_addstring(""); /* lang */ + ssh2_pkt_addstring(""); + ssh2_pkt_send(); + + crWaitUntilV(ispkt); + if (pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) { + if (pktin.type == SSH2_MSG_USERAUTH_FAILURE) + gotit = TRUE; + logevent("Keyboard-interactive authentication refused"); + type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET; + continue; + } + + kbd_inter_running = TRUE; + } + + if (kbd_inter_running) { + method = AUTH_KEYBOARD_INTERACTIVE; + type = AUTH_TYPE_KEYBOARD_INTERACTIVE; + tried_keyb_inter = TRUE; + + ssh_pkt_ctx |= SSH2_PKTCTX_KBDINTER; + + /* We've got packet with that "interactive" info + dump banners, and set its prompt as ours */ + { + char *name, *inst, *lang, *prompt; + int name_len, inst_len, lang_len, prompt_len; + ssh2_pkt_getstring(&name, &name_len); + ssh2_pkt_getstring(&inst, &inst_len); + ssh2_pkt_getstring(&lang, &lang_len); + if (name_len > 0) + c_write_untrusted(name, name_len); + if (inst_len > 0) + c_write_untrusted(inst, inst_len); + num_prompts = ssh2_pkt_getuint32(); + + ssh2_pkt_getstring(&prompt, &prompt_len); + strncpy(pwprompt, prompt, sizeof(pwprompt)); + pwprompt[prompt_len < sizeof(pwprompt) ? + prompt_len : sizeof(pwprompt)-1] = '\0'; + need_pw = TRUE; + + echo = ssh2_pkt_getbool(); + } + } + + if (!method && can_passwd) { + method = AUTH_PASSWORD; + ssh_pkt_ctx |= SSH2_PKTCTX_PASSWORD; + sprintf(pwprompt, "%.90s@%.90s's password: ", username, + savedhost); + need_pw = TRUE; + } + + if (need_pw) { + if (ssh_get_line) { + if (!ssh_get_line(pwprompt, password, + sizeof(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(SSH2_MSG_DISCONNECT); + ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION); + ssh2_pkt_addstring + ("No more passwords available to try"); + ssh2_pkt_addstring("en"); /* language tag */ + ssh2_pkt_send(); + connection_fatal("Unable to authenticate"); + ssh_state = SSH_STATE_CLOSED; + crReturnV; + } + } else { + static int pos = 0; + static char c; + + c_write_untrusted(pwprompt, strlen(pwprompt)); + ssh_send_ok = 1; + + 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: + cleanup_exit(0); + break; + default: + if (pos < sizeof(password)-1) + password[pos++] = c; + break; + } + } + c_write_str("\r\n"); + } + } + + if (method == AUTH_PUBLICKEY_FILE) { + /* + * We have our passphrase. Now try the actual authentication. + */ + struct ssh2_userkey *key; + + key = ssh2_load_userkey(cfg.keyfile, password); + if (key == SSH2_WRONG_PASSPHRASE || key == NULL) { + if (key == SSH2_WRONG_PASSPHRASE) { + c_write_str("Wrong passphrase\r\n"); + tried_pubkey_config = FALSE; + } else { + c_write_str("Unable to load private key\r\n"); + tried_pubkey_config = TRUE; + } + /* Send a spurious AUTH_NONE to return to the top. */ + ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(username); + ssh2_pkt_addstring("ssh-connection"); /* service requested */ + ssh2_pkt_addstring("none"); /* method */ + ssh2_pkt_send(); + type = AUTH_TYPE_NONE; + } else { + unsigned char *blob, *sigdata; + int blob_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(SSH2_MSG_USERAUTH_REQUEST); + ssh2_pkt_addstring(username); + ssh2_pkt_addstring("ssh-connection"); /* service requested */ + ssh2_pkt_addstring("publickey"); /* method */ + ssh2_pkt_addbool(TRUE); + ssh2_pkt_addstring(key->alg->name); + blob = key->alg->public_blob(key->data, &blob_len); + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(blob, blob_len); + sfree(blob); + + /* + * The data to be signed is: + * + * string session-id + * + * followed by everything so far placed in the + * outgoing packet. + */ + sigdata_len = pktout.length - 5 + 4 + 20; + sigdata = smalloc(sigdata_len); + PUT_32BIT(sigdata, 20); + memcpy(sigdata + 4, ssh2_session_id, 20); + memcpy(sigdata + 24, pktout.data + 5, + pktout.length - 5); + blob = + key->alg->sign(key->data, sigdata, sigdata_len, + &blob_len); + ssh2_pkt_addstring_start(); + ssh2_pkt_addstring_data(blob, blob_len); + sfree(blob); + sfree(sigdata); + + ssh2_pkt_send(); + type = AUTH_TYPE_PUBLICKEY; + } + } else if (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(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_defer(); + /* + * 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 (cscipher) { + int stringlen, i; + + stringlen = (256 - deferred_len); + stringlen += cscipher->blksize - 1; + stringlen -= (stringlen % cscipher->blksize); + if (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 -= cscomp->disable_compression(); + } + ssh2_pkt_init(SSH2_MSG_IGNORE); + ssh2_pkt_addstring_start(); + for (i = 0; i < stringlen; i++) { + char c = (char) random_byte(); + ssh2_pkt_addstring_data(&c, 1); + } + ssh2_pkt_defer(); + } + ssh_pkt_defersend(); + logevent("Sent password"); + type = AUTH_TYPE_PASSWORD; + } else if (method == AUTH_KEYBOARD_INTERACTIVE) { + ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE); + ssh2_pkt_adduint32(num_prompts); + ssh2_pkt_addstring(password); + memset(password, 0, sizeof(password)); + ssh2_pkt_send(); + type = AUTH_TYPE_KEYBOARD_INTERACTIVE; } else { - fatalbox("Strange packet received: type %d", pktin.type); + c_write_str + ("No supported authentication methods left to try!\r\n"); + logevent + ("No supported authentications offered. Disconnecting"); + ssh2_pkt_init(SSH2_MSG_DISCONNECT); + ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION); + ssh2_pkt_addstring + ("No supported authentication methods available"); + ssh2_pkt_addstring("en"); /* language tag */ + ssh2_pkt_send(); + ssh_state = SSH_STATE_CLOSED; + crReturnV; } - } else { - s_wrpkt_start(16, 4+inlen); - pktout.body[0] = (inlen >> 24) & 0xFF; - pktout.body[1] = (inlen >> 16) & 0xFF; - pktout.body[2] = (inlen >> 8) & 0xFF; - pktout.body[3] = inlen & 0xFF; - memcpy(pktout.body+4, in, inlen); - s_wrpkt(); } - } + } while (!we_are_in); - crFinishV; -} + /* + * Now we're authenticated for the connection protocol. The + * connection protocol will automatically have started at this + * point; there's no need to send SERVICE_REQUEST. + */ -/* - * 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(). - * - * Returns an error message, or NULL on success. - * - * Also places the canonical host name into `realhost'. - */ -static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) { - SOCKADDR_IN addr; - struct hostent *h; - unsigned long a; -#ifdef FWHACK - char *FWhost; - int FWport; -#endif + /* + * So now create a channel with a session in it. + */ + ssh_channels = newtree234(ssh_channelcmp); + mainchan = smalloc(sizeof(struct ssh_channel)); + mainchan->localid = alloc_channel_id(); + ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN); + ssh2_pkt_addstring("session"); + ssh2_pkt_adduint32(mainchan->localid); + mainchan->v.v2.locwindow = OUR_V2_WINSIZE; + ssh2_pkt_adduint32(mainchan->v.v2.locwindow); /* our window size */ + ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */ + ssh2_pkt_send(); + crWaitUntilV(ispkt); + if (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() != mainchan->localid) { + bombout(("Server's channel confirmation cited wrong channel")); + crReturnV; + } + mainchan->remoteid = ssh2_pkt_getuint32(); + mainchan->type = CHAN_MAINSESSION; + mainchan->closes = 0; + mainchan->v.v2.remwindow = ssh2_pkt_getuint32(); + mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(); + bufchain_init(&mainchan->v.v2.outbuffer); + add234(ssh_channels, mainchan); + logevent("Opened channel for session"); - savedhost = malloc(1+strlen(host)); - if (!savedhost) - fatalbox("Out of memory"); - strcpy(savedhost, host); + /* + * 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(SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(mainchan->remoteid); + ssh2_pkt_addstring("x11-req"); + ssh2_pkt_addbool(1); /* want reply */ + ssh2_pkt_addbool(0); /* many connections */ + ssh2_pkt_addstring(proto); + ssh2_pkt_addstring(data); + ssh2_pkt_adduint32(0); /* screen number */ + ssh2_pkt_send(); -#ifdef FWHACK - FWhost = host; - FWport = port; - host = FWSTR; - port = 23; -#endif + do { + crWaitUntilV(ispkt); + if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(); + } + } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + + if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { + if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { + bombout(("Unexpected response to X11 forwarding request:" + " packet type %d", pktin.type)); + crReturnV; + } + logevent("X11 forwarding refused"); + } else { + logevent("X11 forwarding enabled"); + ssh_X11_fwd_enabled = TRUE; + } + } /* - * Try to find host. + * Enable port forwardings. */ - 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); + { + static char *e; /* preserve across crReturn */ + char type; + int n; + int sport,dport; + char sports[256], dports[256], host[256]; + char buf[1024]; - if (port < 0) - port = 22; /* default ssh port */ + ssh_rportfwds = newtree234(ssh_rportcmp_ssh2); + /* Add port forwardings. */ + e = cfg.portfwd; + while (*e) { + type = *e++; + n = 0; + while (*e && *e != '\t') + sports[n++] = *e++; + sports[n] = 0; + if (*e == '\t') + e++; + n = 0; + while (*e && *e != ':') + host[n++] = *e++; + host[n] = 0; + if (*e == ':') + e++; + n = 0; + while (*e) + dports[n++] = *e++; + dports[n] = 0; + e++; + dport = atoi(dports); + sport = atoi(sports); + if (sport && dport) { + if (type == 'L') { + pfd_addforward(host, dport, sport); + sprintf(buf, "Local port %d forwarding to %s:%d", + sport, host, dport); + 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 %d (forwarded to %s:%d)", + sport, host, dport); + logevent(buf); + ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST); + ssh2_pkt_addstring("tcpip-forward"); + ssh2_pkt_addbool(1);/* want reply */ + if (cfg.rport_acceptall) + ssh2_pkt_addstring("0.0.0.0"); + else + ssh2_pkt_addstring("127.0.0.1"); + ssh2_pkt_adduint32(sport); + ssh2_pkt_send(); + + do { + crWaitUntilV(ispkt); + if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue;/* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(); + } + } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + + if (pktin.type != SSH2_MSG_REQUEST_SUCCESS) { + if (pktin.type != SSH2_MSG_REQUEST_FAILURE) { + bombout(("Unexpected response to port " + "forwarding request: packet type %d", + pktin.type)); + crReturnV; + } + logevent("Server refused this port forwarding"); + } else { + logevent("Remote port forwarding enabled"); + } + } + } + } + } + } /* - * Open socket. + * Potentially enable agent forwarding. */ - 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"; + if (cfg.agentfwd && agent_exists()) { + logevent("Requesting OpenSSH-style agent forwarding"); + ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(mainchan->remoteid); + ssh2_pkt_addstring("auth-agent-req@openssh.com"); + ssh2_pkt_addbool(1); /* want reply */ + ssh2_pkt_send(); + + do { + crWaitUntilV(ispkt); + if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(); + } + } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + + if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { + if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { + bombout(("Unexpected response to agent forwarding request:" + " packet type %d", pktin.type)); + crReturnV; + } + logevent("Agent forwarding refused"); + } else { + logevent("Agent forwarding enabled"); + ssh_agentfwd_enabled = TRUE; } + } /* - * Bind to local address. + * Now allocate a pty for the session. */ - 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"; + if (!cfg.nopty) { + ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(mainchan->remoteid); /* 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(); + ssh_state = SSH_STATE_INTERMED; + + do { + crWaitUntilV(ispkt); + if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(); + } + } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + + if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { + if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { + bombout(("Unexpected response to pty request:" + " packet type %d", pktin.type)); + crReturnV; + } + c_write_str("Server refused to allocate pty\r\n"); + ssh_editing = ssh_echoing = 1; + } else { + logevent("Allocated pty"); } + } else { + ssh_editing = ssh_echoing = 1; + } /* - * Connect to remote address. + * 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. */ - 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"; + 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; } -#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); + ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */ + if (subsys) { + ssh2_pkt_addstring("subsystem"); + ssh2_pkt_addbool(1); /* want reply */ + ssh2_pkt_addstring(cmd); + } else if (*cmd) { + ssh2_pkt_addstring("exec"); + ssh2_pkt_addbool(1); /* want reply */ + ssh2_pkt_addstring(cmd); + } else { + ssh2_pkt_addstring("shell"); + ssh2_pkt_addbool(1); /* want reply */ + } + ssh2_pkt_send(); + do { + crWaitUntilV(ispkt); + if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(); + } + } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST); + if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) { + if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { + bombout(("Unexpected response to shell/command request:" + " packet type %d", 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 (size_needed) + ssh_size(); + if (eof_needed) + ssh_special(TS_EOF); + + /* + * Transfer data! + */ + ldisc_send(NULL, 0, 0); /* cause ldisc to notice changes */ + ssh_send_ok = 1; + while (1) { + static int try_send; + crReturnV; + try_send = FALSE; + if (ispkt) { + if (pktin.type == SSH2_MSG_CHANNEL_DATA || + pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) { + char *data; + int length; + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent 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) { + int bufsize; + c->v.v2.locwindow -= length; + switch (c->type) { + case CHAN_MAINSESSION: + bufsize = + from_backend(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); + 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 (pktin.type == SSH2_MSG_DISCONNECT) { + ssh_state = SSH_STATE_CLOSED; + logevent("Received disconnect message"); + crReturnV; + } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) { + unsigned i = ssh2_pkt_getuint32(); + 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 (pktin.type == SSH2_MSG_CHANNEL_CLOSE) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + /* 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(SSH2_MSG_CHANNEL_CLOSE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } + 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(SSH2_MSG_DISCONNECT); + ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION); + ssh2_pkt_addstring("All open channels closed"); + ssh2_pkt_addstring("en"); /* language tag */ + ssh2_pkt_send(); #endif + ssh_state = SSH_STATE_CLOSED; + crReturnV; + } + continue; /* remote sends close; ignore (FIXME) */ + } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + c->v.v2.remwindow += ssh2_pkt_getuint32(); + try_send = TRUE; + } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) { + unsigned i = ssh2_pkt_getuint32(); + 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(); + c->type = CHAN_SOCKDATA; + c->v.v2.remwindow = ssh2_pkt_getuint32(); + c->v.v2.remmaxpkt = ssh2_pkt_getuint32(); + bufchain_init(&c->v.v2.outbuffer); + 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(SSH2_MSG_CHANNEL_CLOSE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } + } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) { + unsigned i = ssh2_pkt_getuint32(); + 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 */ - if (!do_ssh_init()) - return "Protocol initialisation error"; + logevent("Forwarded connection refused by server"); - if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ | FD_CLOSE) == SOCKET_ERROR) - switch (WSAGetLastError()) { - case WSAENETDOWN: return "Network is down"; - default: return "WSAAsyncSelect(): unknown error"; + pfd_close(c->u.pfd.s); + + del234(ssh_channels, c); + sfree(c); + } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) { + unsigned localid; + char *type; + int typelen, want_reply; + struct ssh_channel *c; + + localid = ssh2_pkt_getuint32(); + ssh2_pkt_getstring(&type, &typelen); + want_reply = ssh2_pkt_getbool(); + + /* + * 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(SSH2_MSG_DISCONNECT); + ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION); + ssh2_pkt_addstring(buf); + ssh2_pkt_addstring("en"); /* language tag */ + ssh2_pkt_send(); + connection_fatal(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 == mainchan) { + /* We recognise "exit-status" on the primary channel. */ + char buf[100]; + ssh_exitcode = ssh2_pkt_getuint32(); + sprintf(buf, "Server sent command exit status %d", + ssh_exitcode); + logevent(buf); + if (want_reply) { + ssh2_pkt_init(SSH2_MSG_CHANNEL_SUCCESS); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } + } 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(SSH2_MSG_CHANNEL_FAILURE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } + } + } else if (pktin.type == SSH2_MSG_GLOBAL_REQUEST) { + char *type; + int typelen, want_reply; + + ssh2_pkt_getstring(&type, &typelen); + want_reply = ssh2_pkt_getbool(); + + /* + * 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(SSH2_MSG_REQUEST_FAILURE); + ssh2_pkt_send(); + } + } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) { + char *type; + int typelen; + char *error = NULL; + struct ssh_channel *c; + unsigned remid, winsize, pktsize; + ssh2_pkt_getstring(&type, &typelen); + c = smalloc(sizeof(struct ssh_channel)); + + remid = ssh2_pkt_getuint32(); + winsize = ssh2_pkt_getuint32(); + pktsize = ssh2_pkt_getuint32(); + + 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(&dummy, &dummylen);/* skip address */ + pf.sport = ssh2_pkt_getuint32(); + 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(SSH2_MSG_CHANNEL_OPEN_FAILURE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED); + ssh2_pkt_addstring(error); + ssh2_pkt_addstring("en"); /* language tag */ + ssh2_pkt_send(); + sfree(c); + } else { + c->localid = alloc_channel_id(); + 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(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_adduint32(c->localid); + ssh2_pkt_adduint32(c->v.v2.locwindow); + ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */ + ssh2_pkt_send(); + } + } else { + bombout(("Strange packet received: type %d", pktin.type)); + crReturnV; + } + } else { + /* + * We have spare data. Add it to the channel buffer. + */ + ssh2_add_channel_data(mainchan, in, inlen); + try_send = TRUE; + } + if (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; + } + } + } } + } - return NULL; + crFinishV; +} + +/* + * Handle the top-level SSH2 protocol. + */ +static void ssh2_protocol(unsigned char *in, int inlen, int ispkt) +{ + if (do_ssh2_transport(in, inlen, ispkt) == 0) + return; + do_ssh2_authconn(in, inlen, ispkt); } /* - * Process a WM_NETEVENT message. Will return 0 if the connection - * has closed, or <0 for a socket error. + * Called to set up the connection. + * + * Returns an error message, or NULL on success. */ -static int ssh_msg (WPARAM wParam, LPARAM lParam) { - int ret; - char buf[256]; +static char *ssh_init(char *host, int port, char **realhost, int nodelay) +{ + char *p; - if (s == INVALID_SOCKET) /* how the hell did we get here?! */ - return -5000; +#ifdef MSCRYPTOAPI + if (crypto_startup() == 0) + return "Microsoft high encryption pack not installed!"; +#endif - if (WSAGETSELECTERROR(lParam) != 0) - return -WSAGETSELECTERROR(lParam); + ssh_send_ok = 0; + ssh_editing = 0; + ssh_echoing = 0; + ssh1_throttle_count = 0; + ssh_overall_bufsize = 0; + ssh_fallback_cmd = 0; - switch (WSAGETSELECTEVENT(lParam)) { - case FD_READ: - 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; /* can't happen, in theory */ - } - ssh_gotdata (buf, ret); - return 1; - case FD_CLOSE: - s = INVALID_SOCKET; - return 0; - } - return 1; /* shouldn't happen, but WTF */ + p = connect_to_host(host, port, realhost, nodelay); + if (p != NULL) + return p; + + return NULL; } /* * Called to send data down the Telnet connection. */ -static void ssh_send (char *buf, int len) { - if (s == INVALID_SOCKET) - return; +static int ssh_send(char *buf, int len) +{ + if (s == NULL || ssh_protocol == NULL) + return 0; ssh_protocol(buf, len, 0); + + return ssh_sendbuffer(); +} + +/* + * Called to query the current amount of buffered stdin data. + */ +static int ssh_sendbuffer(void) +{ + int override_value; + + if (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 (!mainchan || mainchan->closes > 0) + return override_value; + else + return override_value + bufchain_size(&mainchan->v.v2.outbuffer); + } + + 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) { +static void ssh_size(void) +{ 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 */ break; case SSH_STATE_SESSION: - s_wrpkt_start(11, 16); - pktout.body[0] = (rows >> 24) & 0xFF; - pktout.body[1] = (rows >> 16) & 0xFF; - pktout.body[2] = (rows >> 8) & 0xFF; - pktout.body[3] = rows & 0xFF; - pktout.body[4] = (cols >> 24) & 0xFF; - pktout.body[5] = (cols >> 16) & 0xFF; - pktout.body[6] = (cols >> 8) & 0xFF; - pktout.body[7] = cols & 0xFF; - memset(pktout.body+8, 0, 8); - s_wrpkt(); + if (!cfg.nopty) { + if (ssh_version == 1) { + send_packet(SSH1_CMSG_WINDOW_SIZE, + PKT_INT, rows, PKT_INT, cols, + PKT_INT, 0, PKT_INT, 0, PKT_END); + } else { + ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); + ssh2_pkt_adduint32(mainchan->remoteid); + ssh2_pkt_addstring("window-change"); + ssh2_pkt_addbool(0); + ssh2_pkt_adduint32(cols); + ssh2_pkt_adduint32(rows); + ssh2_pkt_adduint32(0); + ssh2_pkt_adduint32(0); + ssh2_pkt_send(); + } + } + break; + } +} + +/* + * Send Telnet special codes. TS_EOF is useful for `plink', so you + * can send an EOF and collect resulting output (e.g. `plink + * hostname sort'). + */ +static void ssh_special(Telnet_Special code) +{ + if (code == TS_EOF) { + 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) + eof_needed = TRUE; + return; + } + if (ssh_version == 1) { + send_packet(SSH1_CMSG_EOF, PKT_END); + } else { + ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF); + ssh2_pkt_adduint32(mainchan->remoteid); + ssh2_pkt_send(); + } + 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) { + send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END); + } else { + ssh2_pkt_init(SSH2_MSG_IGNORE); + ssh2_pkt_addstring_start(); + ssh2_pkt_send(); + } + } else { + /* do nothing */ + } +} + +void *new_sock_channel(Socket s) +{ + struct ssh_channel *c; + c = smalloc(sizeof(struct ssh_channel)); + + if (c) { + c->remoteid = -1; /* to be set when open confirmed */ + c->localid = alloc_channel_id(); + c->closes = 0; + c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */ + c->u.pfd.s = s; + add234(ssh_channels, c); } + return c; } /* - * (Send Telnet special codes) + * This is called when stdout/stderr (the entity to which + * from_backend sends data) manages to clear some backlog. */ -static void ssh_special (Telnet_Special code) { - /* do nothing */ +void ssh_unthrottle(int bufsize) +{ + if (ssh_version == 1) { + if (ssh1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) { + ssh1_stdout_throttling = 0; + ssh1_throttle(-1); + } + } else { + if (mainchan && mainchan->closes == 0) + ssh2_set_window(mainchan, OUR_V2_WINSIZE - bufsize); + } +} + +void ssh_send_port_open(void *channel, char *hostname, int port, char *org) +{ + struct ssh_channel *c = (struct ssh_channel *)channel; + char buf[1024]; + + sprintf(buf, "Opening forwarded connection to %.512s:%d", hostname, port); + logevent(buf); + + if (ssh_version == 1) { + send_packet(SSH1_MSG_PORT_OPEN, + PKT_INT, c->localid, + PKT_STR, hostname, + PKT_INT, port, + //PKT_STR, , + PKT_END); + } else { + ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN); + ssh2_pkt_addstring("direct-tcpip"); + ssh2_pkt_adduint32(c->localid); + c->v.v2.locwindow = OUR_V2_WINSIZE; + ssh2_pkt_adduint32(c->v.v2.locwindow);/* our window size */ + ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */ + ssh2_pkt_addstring(hostname); + ssh2_pkt_adduint32(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("client-side-connection"); + ssh2_pkt_adduint32(0); + ssh2_pkt_send(); + } +} + + +static Socket ssh_socket(void) +{ + return s; +} + +static int ssh_sendok(void) +{ + return ssh_send_ok; +} + +static int ssh_ldisc(int option) +{ + if (option == LD_ECHO) + return ssh_echoing; + if (option == LD_EDIT) + return ssh_editing; + return FALSE; +} + +static int ssh_return_exitcode(void) +{ + return ssh_exitcode; } Backend ssh_backend = { ssh_init, - ssh_msg, ssh_send, + ssh_sendbuffer, ssh_size, - ssh_special + ssh_special, + ssh_socket, + ssh_return_exitcode, + ssh_sendok, + ssh_ldisc, + ssh_unthrottle, + 22 };