X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/e055a386af9c83d4a04e72f7c58805f1197df8be..5471d09ad63fc6216fb9c2a3b52ca9c93821a054:/ssh.c diff --git a/ssh.c b/ssh.c index 92afd085..be346593 100644 --- a/ssh.c +++ b/ssh.c @@ -15,111 +15,150 @@ #define TRUE 1 #endif +/* uncomment this for packet level debugging */ +/* #define DUMP_PACKETS */ + #define logevent(s) { logevent(s); \ if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \ - fprintf(stderr, "%s\n", s); } - -#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, sk_close(s), \ - s = NULL, 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_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */ -#define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */ -#define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */ -#define SSH1_MSG_IGNORE 32 /* 0x20 */ -#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 SSH_AGENTC_REQUEST_RSA_IDENTITIES 1 /* 0x1 */ -#define SSH_AGENT_RSA_IDENTITIES_ANSWER 2 /* 0x2 */ -#define SSH_AGENTC_RSA_CHALLENGE 3 /* 0x3 */ -#define SSH_AGENT_RSA_RESPONSE 4 /* 0x4 */ -#define SSH_AGENT_FAILURE 5 /* 0x5 */ -#define SSH_AGENT_SUCCESS 6 /* 0x6 */ -#define SSH_AGENTC_ADD_RSA_IDENTITY 7 /* 0x7 */ -#define SSH_AGENTC_REMOVE_RSA_IDENTITY 8 /* 0x8 */ - -#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_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_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 */ - -#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_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 */ + { 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 */ + +#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 GET_32BIT(cp) \ (((unsigned long)(unsigned char)(cp)[0] << 24) | \ @@ -154,11 +193,45 @@ enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM }; #define crWaitUntil(c) do { crReturn(0); } while (!(c)) #define crWaitUntilV(c) do { crReturnV; } while (!(c)) -extern const struct ssh_cipher ssh_3des; -extern const struct ssh_cipher ssh_3des_ssh2; -extern const struct ssh_cipher ssh_des; -extern const struct ssh_cipher ssh_blowfish_ssh1; -extern const struct ssh_cipher ssh_blowfish_ssh2; +extern char *x11_init(Socket *, char *, void *); +extern void x11_close(Socket); +extern int x11_send(Socket, char *, int); +extern void x11_invent_auth(char *, int, char *, int); +extern void x11_unthrottle(Socket s); +extern void x11_override_throttle(Socket s, int enable); + +extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c); +extern char *pfd_addforward(char *desthost, int destport, int port); +extern void pfd_close(Socket s); +extern int pfd_send(Socket s, char *data, int len); +extern void pfd_confirm(Socket s); +extern void pfd_unthrottle(Socket s); +extern void pfd_override_throttle(Socket s, int enable); + +/* + * 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. + */ + +#define SSH1_BUFFER_LIMIT 32768 +#define SSH_MAX_BACKLOG 32768 +#define OUR_V2_WINSIZE 16384 /* * Ciphers for SSH2. We miss out single-DES because it isn't @@ -166,40 +239,70 @@ extern const struct ssh_cipher ssh_blowfish_ssh2; * SSH1. (3DES uses outer chaining; Blowfish has the opposite * endianness and different-sized keys.) */ -const static struct ssh_cipher *ciphers[] = { &ssh_blowfish_ssh2, &ssh_3des_ssh2 }; - -extern const struct ssh_kex ssh_diffiehellman; -const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman }; +const static struct ssh2_ciphers *ciphers[] = { + &ssh2_aes, + &ssh2_blowfish, + &ssh2_3des, +}; -extern const struct ssh_signkey ssh_dss; -const static struct ssh_signkey *hostkey_algs[] = { &ssh_dss }; +const static struct ssh_kex *kex_algs[] = { + &ssh_diffiehellman_gex, + &ssh_diffiehellman +}; -extern const struct ssh_mac ssh_md5, ssh_sha1, ssh_sha1_buggy; +const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss }; -static void nullmac_key(unsigned char *key) { } -static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { } -static int nullmac_verify(unsigned char *blk, int len, unsigned long seq) { return 1; } +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 }; + &ssh_sha1, &ssh_md5, &ssh_mac_none +}; const static struct ssh_mac *buggymacs[] = { - &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none }; + &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none +}; -static void ssh_comp_none_init(void) { } +static void ssh_comp_none_init(void) +{ +} static int ssh_comp_none_block(unsigned char *block, int len, - unsigned char **outblock, int *outlen) { + 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_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 }; + &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. @@ -209,19 +312,64 @@ struct ssh_channel { int type; int closes; union { - struct ssh_agent_channel { - unsigned char *message; - unsigned char msglen[4]; - int lensofar, totallen; - } a; - struct ssh2_data_channel { - unsigned char *outbuffer; - unsigned outbuflen, outbufsize; - unsigned remwindow, remmaxpkt; - } v2; + 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; @@ -231,50 +379,72 @@ struct Packet { long maxlen; }; -static SHA_State exhash; +static SHA_State exhash, exhashbase; static Socket s = NULL; 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 ssh_cipher *cscipher = NULL; -static const struct ssh_cipher *sccipher = 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; -int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL; +static unsigned char ssh2_session_id[20]; +int (*ssh_get_line) (const char *prompt, char *str, int maxlen, + int is_pw) = NULL; static char *savedhost; static int savedport; static int ssh_send_ok; +static int ssh_echoing, ssh_editing; -static tree234 *ssh_channels; /* indexed by local id */ +static tree234 *ssh_channels; /* indexed by local id */ static struct ssh_channel *mainchan; /* primary session channel */ +static tree234 *ssh_rportfwds; + static enum { + SSH_STATE_PREPACKET, SSH_STATE_BEFORE_SIZE, SSH_STATE_INTERMED, SSH_STATE_SESSION, SSH_STATE_CLOSED -} ssh_state = SSH_STATE_BEFORE_SIZE; +} ssh_state = SSH_STATE_PREPACKET; -static int size_needed = FALSE; +static int size_needed = FALSE, eof_needed = FALSE; 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; static int ssh_version; -static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt); +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 int (*s_rdpkt)(unsigned char **data, int *datalen); +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); static struct rdpkt1_state_tag { long len, pad, biglen, to_read; @@ -291,32 +461,119 @@ static struct rdpkt2_state_tag { 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; +static int ssh_channelcmp(void *av, void *bv) +{ + struct ssh_channel *a = (struct ssh_channel *) av; + struct ssh_channel *b = (struct ssh_channel *) bv; + if (a->localid < b->localid) + return -1; + if (a->localid > b->localid) + return +1; + return 0; +} +static int ssh_channelfind(void *av, void *bv) +{ + unsigned *a = (unsigned *) av; + struct ssh_channel *b = (struct ssh_channel *) bv; + if (*a < b->localid) + return -1; + if (*a > b->localid) + return +1; + return 0; +} + +static int ssh_rportcmp_ssh1(void *av, void *bv) +{ + struct ssh_rportfwd *a = (struct ssh_rportfwd *) av; + struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv; + int i; + if ( (i = strcmp(a->dhost, b->dhost)) != 0) + return i < 0 ? -1 : +1; + if (a->dport > b->dport) + return +1; + if (a->dport < b->dport) + return -1; return 0; } -static int ssh_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; + +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; + int i; + if (a->sport > b->sport) + return +1; + if (a->sport < b->sport) + return -1; return 0; } -static void c_write (char *buf, int len) { +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; +} + +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); + int i; + for (i = 0; i < len; i++) + if (buf[i] != '\r') + fputc(buf[i], stderr); return; } from_backend(1, buf, len); } +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); + } +} + +static void c_write_str(char *buf) +{ + c_write(buf, strlen(buf)); +} + /* * Collect incoming data in the incoming packet buffer. * Decipher and verify the packet when it is completely read. @@ -331,21 +588,21 @@ static int ssh1_rdpkt(unsigned char **data, int *datalen) crBegin; -next_packet: + next_packet: pktin.type = 0; pktin.length = 0; for (st->i = st->len = 0; st->i < 4; st->i++) { while ((*datalen) == 0) - crReturn(4-st->i); + crReturn(4 - st->i); st->len = (st->len << 8) + **data; (*data)++, (*datalen)--; } #ifdef FWHACK - if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */ - st->len = 0x300; /* big enough to carry to end */ + if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */ + st->len = 0x300; /* big enough to carry to end */ } #endif @@ -355,8 +612,8 @@ next_packet: if (pktin.maxlen < st->biglen) { pktin.maxlen = st->biglen; - pktin.data = (pktin.data == NULL ? malloc(st->biglen+APIEXTRA) : - realloc(pktin.data, st->biglen+APIEXTRA)); + pktin.data = (pktin.data == NULL ? smalloc(st->biglen + APIEXTRA) : + srealloc(pktin.data, st->biglen + APIEXTRA)); if (!pktin.data) fatalbox("Out of memory"); } @@ -364,7 +621,7 @@ next_packet: st->to_read = st->biglen; st->p = pktin.data; while (st->to_read > 0) { - st->chunk = st->to_read; + st->chunk = st->to_read; while ((*datalen) == 0) crReturn(st->to_read); if (st->chunk > (*datalen)) @@ -378,18 +635,16 @@ next_packet: if (cipher) cipher->decrypt(pktin.data, st->biglen); -#if 0 - debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad)); - for (st->i = 0; st->i < st->biglen; st->i++) - debug((" %02x", (unsigned char)pktin.data[st->i])); - debug(("\r\n")); +#ifdef DUMP_PACKETS + debug(("Got packet len=%d pad=%d\n", st->len, st->pad)); + dmemdump(pktin.data, st->biglen); #endif - st->realcrc = crc32(pktin.data, st->biglen-4); - st->gotcrc = GET_32BIT(pktin.data+st->biglen-4); + 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); + crReturn(0); } pktin.body = pktin.data + st->pad + 1; @@ -397,44 +652,40 @@ next_packet: if (ssh1_compressing) { unsigned char *decompblk; int decomplen; -#if 0 - int i; +#ifdef DUMP_PACKETS debug(("Packet payload pre-decompression:\n")); - for (i = -1; i < pktin.length; i++) - debug((" %02x", (unsigned char)pktin.body[i])); - debug(("\r\n")); + dmemdump(pktin.body - 1, pktin.length + 1); #endif - zlib_decompress_block(pktin.body-1, pktin.length+1, + zlib_decompress_block(pktin.body - 1, pktin.length + 1, &decompblk, &decomplen); if (pktin.maxlen < st->pad + decomplen) { pktin.maxlen = st->pad + decomplen; - pktin.data = realloc(pktin.data, pktin.maxlen+APIEXTRA); + pktin.data = srealloc(pktin.data, pktin.maxlen + APIEXTRA); + pktin.body = pktin.data + st->pad + 1; if (!pktin.data) fatalbox("Out of memory"); } - memcpy(pktin.body-1, decompblk, decomplen); - free(decompblk); - pktin.length = decomplen-1; -#if 0 + memcpy(pktin.body - 1, decompblk, decomplen); + sfree(decompblk); + pktin.length = decomplen - 1; +#ifdef DUMP_PACKETS debug(("Packet payload post-decompression:\n")); - for (i = -1; i < pktin.length; i++) - debug((" %02x", (unsigned char)pktin.body[i])); - debug(("\r\n")); + dmemdump(pktin.body - 1, pktin.length + 1); #endif } 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) { + pktin.type == SSH1_SMSG_STDERR_DATA || + pktin.type == SSH1_MSG_DEBUG || + pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE || + pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) { long strlen = GET_32BIT(pktin.body); if (strlen + 4 != pktin.length) { bombout(("Received data packet with bogus string length")); - crReturn(0); - } + crReturn(0); + } } pktin.type = pktin.body[-1]; @@ -444,9 +695,10 @@ next_packet: char buf[80]; int strlen = GET_32BIT(pktin.body); strcpy(buf, "Remote: "); - if (strlen > 70) strlen = 70; - memcpy(buf+8, pktin.body+4, strlen); - buf[8+strlen] = '\0'; + if (strlen > 70) + strlen = 70; + memcpy(buf + 8, pktin.body + 4, strlen); + buf[8 + strlen] = '\0'; logevent(buf); goto next_packet; } else if (pktin.type == SSH1_MSG_IGNORE) { @@ -454,6 +706,20 @@ next_packet: goto next_packet; } + 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); + } + crFinish(0); } @@ -463,20 +729,24 @@ static int ssh2_rdpkt(unsigned char **data, int *datalen) crBegin; -next_packet: + next_packet: pktin.type = 0; pktin.length = 0; if (sccipher) - st->cipherblk = sccipher->blksize; + st->cipherblk = sccipher->blksize; else - st->cipherblk = 8; + st->cipherblk = 8; if (st->cipherblk < 8) - st->cipherblk = 8; + st->cipherblk = 8; if (pktin.maxlen < st->cipherblk) { pktin.maxlen = st->cipherblk; - pktin.data = (pktin.data == NULL ? malloc(st->cipherblk+APIEXTRA) : - realloc(pktin.data, st->cipherblk+APIEXTRA)); + pktin.data = + (pktin.data == + NULL ? smalloc(st->cipherblk + + APIEXTRA) : srealloc(pktin.data, + st->cipherblk + + APIEXTRA)); if (!pktin.data) fatalbox("Out of memory"); } @@ -485,19 +755,19 @@ next_packet: * 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++) { + for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) { while ((*datalen) == 0) - crReturn(st->cipherblk-st->i); + crReturn(st->cipherblk - st->i); pktin.data[st->i] = *(*data)++; - (*datalen)--; + (*datalen)--; } #ifdef FWHACK - if (!memcmp(pktin.data, "Remo", 4)) {/* "Remo"te server has closed ... */ - /* FIXME */ + if (!memcmp(pktin.data, "Remo", 4)) { /* "Remo"te server has closed ... */ + /* FIXME */ } #endif if (sccipher) - sccipher->decrypt(pktin.data, st->cipherblk); + sccipher->decrypt(pktin.data, st->cipherblk); /* * Now get the length and padding figures. @@ -521,10 +791,14 @@ next_packet: /* * 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 ? malloc(pktin.maxlen+APIEXTRA) : - realloc(pktin.data, pktin.maxlen+APIEXTRA)); + 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"); } @@ -532,32 +806,33 @@ next_packet: /* * Read and decrypt the remainder of the packet. */ - for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen; st->i++) { + 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)--; + (*datalen)--; } /* Decrypt everything _except_ the MAC. */ if (sccipher) - sccipher->decrypt(pktin.data + st->cipherblk, - st->packetlen - st->cipherblk); + sccipher->decrypt(pktin.data + st->cipherblk, + st->packetlen - st->cipherblk); -#if 0 - debug(("Got packet len=%d pad=%d\r\n", st->len, st->pad)); - for (st->i = 0; st->i < st->packetlen; st->i++) - debug((" %02x", (unsigned char)pktin.data[st->i])); - debug(("\r\n")); +#ifdef DUMP_PACKETS + debug(("Got packet len=%d pad=%d\n", st->len, st->pad)); + dmemdump(pktin.data, st->packetlen); #endif /* * Check the MAC. */ - if (scmac && !scmac->verify(pktin.data, st->len+4, st->incoming_sequence)) { + if (scmac + && !scmac->verify(pktin.data, st->len + 4, + st->incoming_sequence)) { bombout(("Incorrect MAC received on packet")); - crReturn(0); + crReturn(0); } - st->incoming_sequence++; /* whether or not we MACed */ + st->incoming_sequence++; /* whether or not we MACed */ /* * Decompress packet payload. @@ -565,25 +840,27 @@ next_packet: { unsigned char *newpayload; int newlen; - if (sccomp && sccomp->decompress(pktin.data+5, pktin.length-5, + 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 ? malloc(pktin.maxlen+APIEXTRA) : - realloc(pktin.data, pktin.maxlen+APIEXTRA)); + 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"); } pktin.length = 5 + newlen; - memcpy(pktin.data+5, newpayload, newlen); -#if 0 - debug(("Post-decompression payload:\r\n")); - for (st->i = 0; st->i < newlen; st->i++) - debug((" %02x", (unsigned char)pktin.data[5+st->i])); - debug(("\r\n")); + memcpy(pktin.data + 5, newpayload, newlen); +#ifdef DUMP_PACKETS + debug(("Post-decompression payload:\n")); + dmemdump(pktin.data + 5, newlen); #endif - free(newpayload); + sfree(newpayload); } } @@ -591,297 +868,384 @@ next_packet: pktin.type = pktin.data[5]; if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG) - goto next_packet; /* FIXME: print DEBUG message */ + goto next_packet; /* FIXME: print DEBUG message */ + + if (pktin.type == 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); + } crFinish(0); } -static void ssh1_pktout_size(int len) { +static void ssh1_pktout_size(int len) +{ int pad, biglen; len += 5; /* type and CRC */ - pad = 8 - (len%8); + pad = 8 - (len % 8); biglen = len + pad; - pktout.length = len-5; + 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 ? malloc(biglen+12) : - realloc(pktout.data, biglen+12)); + pktout.data = (pktout.data == NULL ? smalloc(biglen + 12) : + srealloc(pktout.data, biglen + 12)); #else - pktout.data = (pktout.data == NULL ? malloc(biglen+4) : - realloc(pktout.data, biglen+4)); + 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; + pktout.body = pktout.data + 4 + pad + 1; } -static void s_wrpkt_start(int type, int len) { +static void s_wrpkt_start(int type, int len) +{ ssh1_pktout_size(len); pktout.type = type; } -static void s_wrpkt(void) { +static int s_wrpkt_prepare(void) +{ int pad, len, biglen, i; unsigned long crc; pktout.body[-1] = pktout.type; +#ifdef DUMP_PACKETS + debug(("Packet payload pre-compression:\n")); + dmemdump(pktout.body - 1, pktout.length + 1); +#endif + if (ssh1_compressing) { unsigned char *compblk; int complen; -#if 0 - debug(("Packet payload pre-compression:\n")); - for (i = -1; i < pktout.length; i++) - debug((" %02x", (unsigned char)pktout.body[i])); - debug(("\r\n")); -#endif - zlib_compress_block(pktout.body-1, pktout.length+1, + zlib_compress_block(pktout.body - 1, pktout.length + 1, &compblk, &complen); - ssh1_pktout_size(complen-1); - memcpy(pktout.body-1, compblk, complen); - free(compblk); -#if 0 + ssh1_pktout_size(complen - 1); + memcpy(pktout.body - 1, compblk, complen); + sfree(compblk); +#ifdef DUMP_PACKETS debug(("Packet payload post-compression:\n")); - for (i = -1; i < pktout.length; i++) - debug((" %02x", (unsigned char)pktout.body[i])); - debug(("\r\n")); + dmemdump(pktout.body - 1, pktout.length + 1); #endif } len = pktout.length + 5; /* type and CRC */ - pad = 8 - (len%8); + pad = 8 - (len % 8); biglen = len + pad; - for (i=0; iencrypt(pktout.data+4, biglen); + cipher->encrypt(pktout.data + 4, biglen); + + return biglen + 4; +} - sk_write(s, pktout.data, 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 and - * send it to the server. + * Construct a packet with the specified contents. */ -static void send_packet(int pkttype, ...) +static void construct_packet(int pkttype, va_list ap1, va_list ap2) { - va_list args; unsigned char *p, *argp, argchar; unsigned long argint; int pktlen, argtype, arglen; Bignum bn; pktlen = 0; - va_start(args, pkttype); - while ((argtype = va_arg(args, int)) != PKT_END) { + while ((argtype = va_arg(ap1, int)) != PKT_END) { switch (argtype) { case PKT_INT: - (void) va_arg(args, int); + (void) va_arg(ap1, int); pktlen += 4; break; case PKT_CHAR: - (void) va_arg(args, char); + (void) va_arg(ap1, char); pktlen++; break; case PKT_DATA: - (void) va_arg(args, unsigned char *); - arglen = va_arg(args, int); + (void) va_arg(ap1, unsigned char *); + arglen = va_arg(ap1, int); pktlen += arglen; break; case PKT_STR: - argp = va_arg(args, unsigned char *); + argp = va_arg(ap1, unsigned char *); arglen = strlen(argp); pktlen += 4 + arglen; break; case PKT_BIGNUM: - bn = va_arg(args, Bignum); - pktlen += ssh1_bignum_length(bn); + bn = va_arg(ap1, Bignum); + pktlen += ssh1_bignum_length(bn); break; default: assert(0); } } - va_end(args); s_wrpkt_start(pkttype, pktlen); p = pktout.body; - va_start(args, pkttype); - while ((argtype = va_arg(args, int)) != PKT_END) { + while ((argtype = va_arg(ap2, int)) != PKT_END) { switch (argtype) { case PKT_INT: - argint = va_arg(args, int); + argint = va_arg(ap2, int); PUT_32BIT(p, argint); p += 4; break; case PKT_CHAR: - argchar = va_arg(args, unsigned char); + argchar = va_arg(ap2, unsigned char); *p = argchar; p++; break; case PKT_DATA: - argp = va_arg(args, unsigned char *); - arglen = va_arg(args, int); + argp = va_arg(ap2, unsigned char *); + arglen = va_arg(ap2, int); memcpy(p, argp, arglen); p += arglen; break; case PKT_STR: - argp = va_arg(args, unsigned char *); + argp = va_arg(ap2, unsigned char *); arglen = strlen(argp); PUT_32BIT(p, arglen); memcpy(p + 4, argp, arglen); p += 4 + arglen; break; case PKT_BIGNUM: - bn = va_arg(args, Bignum); - p += ssh1_write_bignum(p, bn); + bn = va_arg(ap2, Bignum); + p += ssh1_write_bignum(p, bn); break; } } - va_end(args); +} +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 int ssh_versioncmp(char *a, char *b) { +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++; + if (av != bv) + return (av < bv ? -1 : +1); + if (*ae == '.') + ae++; + if (*be == '.') + be++; av = strtoul(ae, &ae, 10); bv = strtoul(be, &be, 10); - if (av != bv) return (av < bv ? -1 : +1); + if (av != bv) + return (av < bv ? -1 : +1); return 0; } /* - * Utility routine for putting an SSH-protocol `string' into a SHA - * state. + * Utility routines for putting an SSH-protocol `string' and + * `uint32' into a SHA state. */ #include -static void sha_string(SHA_State *s, void *str, int len) { +static void sha_string(SHA_State * s, void *str, int len) +{ unsigned char lenblk[4]; PUT_32BIT(lenblk, len); SHA_Bytes(s, lenblk, 4); SHA_Bytes(s, str, len); } +static void sha_uint32(SHA_State * s, unsigned i) +{ + unsigned char intblk[4]; + PUT_32BIT(intblk, i); + SHA_Bytes(s, intblk, 4); +} + /* * SSH2 packet construction functions. */ -static void ssh2_pkt_adddata(void *data, int len) { - pktout.length += len; - if (pktout.maxlen < pktout.length) { - pktout.maxlen = pktout.length + 256; - pktout.data = (pktout.data == NULL ? malloc(pktout.maxlen+APIEXTRA) : - realloc(pktout.data, pktout.maxlen+APIEXTRA)); - if (!pktout.data) - fatalbox("Out of memory"); +static void ssh2_pkt_ensure(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"); } - memcpy(pktout.data+pktout.length-len, data, len); } -static void ssh2_pkt_addbyte(unsigned char byte) { +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) { +static void ssh2_pkt_init(int pkt_type) +{ pktout.length = 5; - ssh2_pkt_addbyte((unsigned char)pkt_type); + ssh2_pkt_addbyte((unsigned char) pkt_type); } -static void ssh2_pkt_addbool(unsigned char value) { +static void ssh2_pkt_addbool(unsigned char value) +{ ssh2_pkt_adddata(&value, 1); } -static void ssh2_pkt_adduint32(unsigned long value) { +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) { +static void ssh2_pkt_addstring_start(void) +{ ssh2_pkt_adduint32(0); pktout.savedpos = pktout.length; } -static void ssh2_pkt_addstring_str(char *data) { +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); + pktout.length - pktout.savedpos); } -static void ssh2_pkt_addstring_data(char *data, int len) { +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); + pktout.length - pktout.savedpos); } -static void ssh2_pkt_addstring(char *data) { +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) { +static char *ssh2_mpint_fmt(Bignum b, int *len) +{ unsigned char *p; - int i, n = b[0]; - p = malloc(n * 2 + 1); + int i, n = (bignum_bitcount(b) + 7) / 8; + p = smalloc(n + 1); if (!p) - fatalbox("out of memory"); + fatalbox("out of memory"); p[0] = 0; - for (i = 0; i < n; i++) { - p[i*2+1] = (b[n-i] >> 8) & 0xFF; - p[i*2+2] = (b[n-i] ) & 0xFF; - } + for (i = 1; i <= n; i++) + p[i] = bignum_byte(b, n - i); i = 0; - while (p[i] == 0 && (p[i+1] & 0x80) == 0) - i++; - memmove(p, p+i, n*2+1-i); - *len = n*2+1-i; + while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0) + i++; + memmove(p, p + i, n + 1 - i); + *len = n + 1 - i; return p; } -static void ssh2_pkt_addmp(Bignum b) { +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); - free(p); + sfree(p); } -static void ssh2_pkt_send(void) { + +/* + * Construct an SSH2 final-form packet: compress it, encrypt it, + * put the MAC on it. Final packet, ready to be sent, is stored in + * pktout.data. Total length is returned. + */ +static int ssh2_pkt_construct(void) +{ int cipherblk, maclen, padding, i; static unsigned long outgoing_sequence = 0; /* * Compress packet payload. */ -#if 0 - debug(("Pre-compression payload:\r\n")); - for (i = 5; i < pktout.length; i++) - debug((" %02x", (unsigned char)pktout.data[i])); - debug(("\r\n")); +#ifdef DUMP_PACKETS + debug(("Pre-compression payload:\n")); + dmemdump(pktout.data + 5, pktout.length - 5); #endif { unsigned char *newpayload; int newlen; - if (cscomp && cscomp->compress(pktout.data+5, pktout.length-5, + if (cscomp && cscomp->compress(pktout.data + 5, pktout.length - 5, &newpayload, &newlen)) { pktout.length = 5; ssh2_pkt_adddata(newpayload, newlen); - free(newpayload); + sfree(newpayload); } } @@ -889,105 +1253,204 @@ static void ssh2_pkt_send(void) { * Add padding. At least four bytes, and must also bring total * length (minus MAC) up to a multiple of the block size. */ - cipherblk = cipher ? cipher->blksize : 8; /* block size */ - cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */ + cipherblk = 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; + 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(); + 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 */ + csmac->generate(pktout.data, pktout.length + padding, + outgoing_sequence); + outgoing_sequence++; /* whether or not we MACed */ -#if 0 - debug(("Sending packet len=%d\r\n", pktout.length+padding)); - for (i = 0; i < pktout.length+padding; i++) - debug((" %02x", (unsigned char)pktout.data[i])); - debug(("\r\n")); +#ifdef DUMP_PACKETS + debug(("Sending packet len=%d\n", pktout.length + padding)); + dmemdump(pktout.data, pktout.length + padding); #endif if (cscipher) - cscipher->encrypt(pktout.data, pktout.length + padding); - maclen = csmac ? csmac->len : 0; + cscipher->encrypt(pktout.data, pktout.length + padding); - sk_write(s, pktout.data, pktout.length + padding + maclen); + /* 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) { +void bndebug(char *string, Bignum b) +{ unsigned char *p; int i, len; p = ssh2_mpint_fmt(b, &len); debug(("%s", string)); for (i = 0; i < len; i++) - debug((" %02x", p[i])); - debug(("\r\n")); - free(p); + debug((" %02x", p[i])); + debug(("\n")); + sfree(p); } #endif -static void sha_mpint(SHA_State *s, Bignum b) { +static void sha_mpint(SHA_State * s, Bignum b) +{ unsigned char *p; int len; p = ssh2_mpint_fmt(b, &len); sha_string(s, p, len); - free(p); + sfree(p); } /* * SSH2 packet decode functions. */ -static unsigned long ssh2_pkt_getuint32(void) { +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); + return 0; /* arrgh, no way to decline (FIXME?) */ + value = GET_32BIT(pktin.data + pktin.savedpos); pktin.savedpos += 4; return value; } -static void ssh2_pkt_getstring(char **p, int *length) { +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); + return; + *length = GET_32BIT(pktin.data + pktin.savedpos); pktin.savedpos += 4; if (pktin.length - pktin.savedpos < *length) - return; - *p = pktin.data+pktin.savedpos; + return; + *p = pktin.data + pktin.savedpos; pktin.savedpos += *length; } -static Bignum ssh2_pkt_getmp(void) { +static Bignum ssh2_pkt_getmp(void) +{ char *p; - int i, j, length; + int length; Bignum b; ssh2_pkt_getstring(&p, &length); if (!p) - return NULL; + return NULL; if (p[0] & 0x80) { - bombout(("internal error: Can't handle negative mpints")); - return NULL; - } - b = newbn((length+1)/2); - for (i = 0; i < length; i++) { - j = length - 1 - i; - if (j & 1) - b[j/2+1] |= ((unsigned char)p[i]) << 8; - else - b[j/2+1] |= ((unsigned char)p[i]); - } - while (b[0] > 1 && b[b[0]] == 0) b[0]--; + bombout(("internal error: Can't handle negative mpints")); + return NULL; + } + b = bignum_from_bytes(p, length); return b; } -static int do_ssh_init(unsigned char c) { - static char *vsp; +/* + * 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")) { + /* + * 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 (!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[80]; - static char vlog[sizeof(vstring)+20]; + static char *vstring; + static int vstrsize; + static char *vlog; static int i; crBegin; @@ -998,79 +1461,96 @@ static int do_ssh_init(unsigned char c) { static const int transS[] = { 1, 2, 2, 1 }; static const int transH[] = { 0, 0, 3, 0 }; static const int transminus[] = { 0, 0, 0, -1 }; - if (c == 'S') i = transS[i]; - else if (c == 'H') i = transH[i]; - else if (c == '-') i = transminus[i]; - else i = 0; + 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 */ } + vstring = smalloc(16); + vstrsize = 16; strcpy(vstring, "SSH-"); - vsp = vstring+4; + vslen = 4; i = 0; while (1) { crReturn(1); /* get another char */ - if (vsp < vstring+sizeof(vstring)-1) - *vsp++ = c; + 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) + } else if (i < sizeof(version) - 1) version[i++] = c; - } - else if (c == '\n') + } else if (c == '\n') break; } ssh_agentfwd_enabled = FALSE; rdpkt2_state.incoming_sequence = 0; - *vsp = 0; + vstring[vslen] = 0; + vlog = smalloc(20 + vslen); sprintf(vlog, "Server version: %s", vstring); + ssh_detect_bugs(vstring); vlog[strcspn(vlog, "\r\n")] = '\0'; logevent(vlog); + 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 = "SSH-2.0-PuTTY"; - SHA_Init(&exhash); - /* - * Hash our version string and their version string. - */ - sha_string(&exhash, verstring, strlen(verstring)); - sha_string(&exhash, vstring, strcspn(vstring, "\r\n")); - sprintf(vstring, "%s\n", verstring); - sprintf(vlog, "We claim version: %s", verstring); - logevent(vlog); - logevent("Using SSH protocol version 2"); - sk_write(s, vstring, strlen(vstring)); - ssh_protocol = ssh2_protocol; - ssh_version = 2; - s_rdpkt = ssh2_rdpkt; + /* + * 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. - */ - sprintf(vstring, "SSH-%s-PuTTY\n", - (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5")); - sprintf(vlog, "We claim version: %s", vstring); - vlog[strcspn(vlog, "\r\n")] = '\0'; - logevent(vlog); - logevent("Using SSH protocol version 1"); - sk_write(s, vstring, strlen(vstring)); - ssh_protocol = ssh1_protocol; - ssh_version = 1; - s_rdpkt = ssh1_rdpkt; + /* + * 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); } @@ -1090,7 +1570,8 @@ static void ssh_gotdata(unsigned char *data, int datalen) if (datalen == 0) crReturnV; /* more data please */ ret = do_ssh_init(*data); - data++; datalen--; + data++; + datalen--; if (ret == 0) break; } @@ -1105,7 +1586,7 @@ static void ssh_gotdata(unsigned char *data, int datalen) crReturnV; while (1) { while (datalen > 0) { - if ( s_rdpkt(&data, &datalen) == 0 ) { + if (s_rdpkt(&data, &datalen) == 0) { ssh_protocol(NULL, 0, 1); if (ssh_state == SSH_STATE_CLOSED) { return; @@ -1117,31 +1598,61 @@ static void ssh_gotdata(unsigned char *data, int datalen) crFinishV; } -static int ssh_receive(Socket skt, int urgent, char *data, int len) { - if (!len) { - /* Connection has closed. */ - sk_close(s); - s = NULL; - return 0; +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. */ } - ssh_gotdata (data, len); + 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; + 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'. + * 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) { + 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 @@ -1149,7 +1660,7 @@ static char *connect_to_host(char *host, int port, char **realhost) int FWport; #endif - savedhost = malloc(1+strlen(host)); + savedhost = smalloc(1 + strlen(host)); if (!savedhost) fatalbox("Out of memory"); strcpy(savedhost, host); @@ -1169,18 +1680,18 @@ static char *connect_to_host(char *host, int port, char **realhost) * Try to find host. */ addr = sk_namelookup(host, realhost); - if ( (err = sk_addr_error(addr)) ) + if ((err = sk_addr_error(addr))) return err; #ifdef FWHACK - *realhost = FWhost; + *realhost = strdup(FWhost); #endif /* * Open socket. */ - s = sk_new(addr, port, ssh_receive); - if ( (err = sk_socket_error(s)) ) + s = sk_new(addr, port, 0, 1, &fn_table_ptr); + if ((err = sk_socket_error(s))) return err; #ifdef FWHACK @@ -1197,36 +1708,88 @@ static char *connect_to_host(char *host, int port, char **realhost) } /* + * 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, len; - unsigned char *rsabuf, *keystr1, *keystr2; + 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; static unsigned char session_id[16]; - int cipher_type; + static int cipher_type; static char username[100]; crBegin; - if (!ispkt) crWaitUntil(ispkt); + if (!ispkt) + crWaitUntil(ispkt); if (pktin.type != SSH1_SMSG_PUBLIC_KEY) { bombout(("Public key packet not received")); - crReturn(0); + 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); + i = makekey(pktin.body + 8, &servkey, &keystr1, 0); + j = makekey(pktin.body + 8 + i, &hostkey, &keystr2, 0); /* * Log the host key fingerprint. @@ -1235,14 +1798,19 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) char logmsg[80]; logevent("Host key fingerprint is:"); strcpy(logmsg, " "); - hostkey.comment = NULL; - rsa_fingerprint(logmsg+strlen(logmsg), sizeof(logmsg)-strlen(logmsg), - &hostkey); + hostkey.comment = NULL; + rsa_fingerprint(logmsg + strlen(logmsg), + sizeof(logmsg) - strlen(logmsg), &hostkey); logevent(logmsg); } - supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j); - supported_auths_mask = GET_32BIT(pktin.body+16+i+j); + 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); @@ -1250,12 +1818,12 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) MD5Update(&md5c, pktin.body, 8); MD5Final(session_id, &md5c); - for (i=0; i<32; i++) + for (i = 0; i < 32; i++) session_key[i] = random_byte(); len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes); - rsabuf = malloc(len); + rsabuf = smalloc(len); if (!rsabuf) fatalbox("Out of memory"); @@ -1263,21 +1831,22 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) * Verify the host key. */ { - /* - * First format the key into a string. - */ - int len = rsastr_len(&hostkey); - char fingerprint[100]; - char *keystr = malloc(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); - free(keystr); - } - - for (i=0; i<32; i++) { + /* + * 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]; @@ -1293,41 +1862,63 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) logevent("Encrypted session key"); - cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH : - cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES : - SSH_CIPHER_3DES; + switch (cfg.cipher) { + case CIPHER_BLOWFISH: + cipher_type = SSH_CIPHER_BLOWFISH; + break; + case CIPHER_DES: + cipher_type = SSH_CIPHER_DES; + break; + case CIPHER_3DES: + cipher_type = SSH_CIPHER_3DES; + break; + case CIPHER_AES: + c_write_str("AES not supported in SSH1, falling back to 3DES\r\n"); + cipher_type = SSH_CIPHER_3DES; + break; + } if ((supported_ciphers_mask & (1 << cipher_type)) == 0) { - c_write("Selected cipher not supported, falling back to 3DES\r\n", 53); + c_write_str + ("Selected cipher not supported, falling back to 3DES\r\n"); cipher_type = SSH_CIPHER_3DES; + if ((supported_ciphers_mask & (1 << cipher_type)) == 0) { + bombout(("Server violates SSH 1 protocol by " + "not supporting 3DES encryption")); + crReturn(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; + case SSH_CIPHER_3DES: + logevent("Using 3DES encryption"); + break; + case SSH_CIPHER_DES: + logevent("Using single-DES encryption"); + break; + case SSH_CIPHER_BLOWFISH: + logevent("Using Blowfish encryption"); + break; } send_packet(SSH1_CMSG_SESSION_KEY, - PKT_CHAR, cipher_type, - PKT_DATA, cookie, 8, - PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF, - PKT_DATA, rsabuf, len, - PKT_INT, 0, - PKT_END); + 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..."); - free(rsabuf); + sfree(rsabuf); cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 : - cipher_type == SSH_CIPHER_DES ? &ssh_des : - &ssh_3des; + 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); + crReturn(0); } logevent("Successfully started encryption"); @@ -1337,42 +1928,61 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) static int pos = 0; static char c; if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { - c_write("login as: ", 10); - 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("\b \b", 3); - pos--; - } - break; - case 21: case 27: - while (pos > 0) { - c_write("\b \b", 3); - pos--; - } - break; - case 3: case 4: - random_save_seed(); - exit(0); - break; - default: - if (((c >= ' ' && c <= '~') || - ((unsigned char)c >= 160)) && pos < 40) { - username[pos++] = c; - c_write(&c, 1); - } - break; + if (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: + random_save_seed(); + 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'; } - c_write("\r\n", 2); - username[strcspn(username, "\n\r")] = '\0'; } else { strncpy(username, cfg.username, 99); username[99] = '\0'; @@ -1380,13 +1990,13 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END); { - char userlog[22+sizeof(username)]; + char userlog[22 + sizeof(username)]; sprintf(userlog, "Sent username \"%s\"", username); logevent(userlog); - if (flags & FLAG_INTERACTIVE && - (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) { + if (flags & FLAG_INTERACTIVE && + (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) { strcat(userlog, "\r\n"); - c_write(userlog, strlen(userlog)); + c_write_str(userlog); } } } @@ -1400,312 +2010,423 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) static char prompt[200]; static int pos; static char c; - static int pwpkt_type; - /* - * Show password prompt, having first obtained it via a TIS - * or CryptoCard exchange if we're doing TIS or CryptoCard - * authentication. - */ - pwpkt_type = SSH1_CMSG_AUTH_PASSWORD; - if (agent_exists()) { - /* - * Attempt RSA authentication using Pageant. - */ - static unsigned char request[5], *response, *p; - static int responselen; - static int i, nkeys; - static int authed = FALSE; - void *r; - - logevent("Pageant is running. Requesting keys."); - - /* Request the keys held by the agent. */ - PUT_32BIT(request, 1); - request[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES; - agent_query(request, 5, &r, &responselen); - response = (unsigned char *)r; - if (response) { - p = response + 5; - nkeys = GET_32BIT(p); p += 4; - { char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys); - logevent(buf); } - for (i = 0; i < nkeys; i++) { - static struct RSAKey key; - static Bignum challenge; - static char *commentp; - static int commentlen; - - { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i); - logevent(buf); } - p += 4; - p += ssh1_read_bignum(p, &key.exponent); - p += ssh1_read_bignum(p, &key.modulus); - 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; - int len, retlen; - len = 1 + 4; /* message type, bit count */ - len += ssh1_bignum_length(key.exponent); - len += ssh1_bignum_length(key.modulus); - len += ssh1_bignum_length(challenge); - len += 16; /* session id */ - len += 4; /* response format */ - agentreq = malloc(4 + len); - PUT_32BIT(agentreq, len); - q = agentreq + 4; - *q++ = SSH_AGENTC_RSA_CHALLENGE; - PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus)); - q += 4; - q += ssh1_write_bignum(q, key.exponent); - q += ssh1_write_bignum(q, key.modulus); - q += ssh1_write_bignum(q, challenge); - memcpy(q, session_id, 16); q += 16; - PUT_32BIT(q, 1); /* response format */ - agent_query(agentreq, len+4, &ret, &retlen); - free(agentreq); - if (ret) { - if (ret[4] == SSH_AGENT_RSA_RESPONSE) { - logevent("Sending Pageant's response"); - send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE, - PKT_DATA, ret+5, 16, PKT_END); - free(ret); - crWaitUntil(ispkt); - if (pktin.type == SSH1_SMSG_SUCCESS) { - logevent("Pageant's response accepted"); - if (flags & FLAG_VERBOSE) { - c_write("Authenticated using RSA key \"", - 29); - c_write(commentp, commentlen); - c_write("\" from agent\r\n", 14); - } - authed = TRUE; - } else - logevent("Pageant's response not accepted"); - } else { - logevent("Pageant failed to answer challenge"); - free(ret); - } - } else { - logevent("No reply received from Pageant"); - } - } - freebn(key.exponent); - freebn(key.modulus); - freebn(challenge); - if (authed) - break; - } - } - if (authed) - break; - } - if (*cfg.keyfile && !tried_publickey) - pwpkt_type = SSH1_CMSG_AUTH_RSA; - - if (pktin.type == SSH1_SMSG_FAILURE && - cfg.try_tis_auth && - (supported_auths_mask & (1< sizeof(prompt)-1) - challengelen = sizeof(prompt)-1; /* prevent overrun */ - memcpy(prompt, pktin.body+4, challengelen); - prompt[challengelen] = '\0'; - } - } - if (pktin.type == SSH1_SMSG_FAILURE && - cfg.try_tis_auth && - (supported_auths_mask & (1< sizeof(prompt)-1) - challengelen = sizeof(prompt)-1; /* prevent overrun */ - memcpy(prompt, pktin.body+4, challengelen); - strncpy(prompt + 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("Trying public key authentication.\r\n", 35); - if (!rsakey_encrypted(cfg.keyfile, &comment)) { - if (flags & FLAG_VERBOSE) - c_write("No passphrase required.\r\n", 25); - goto tryauth; - } - sprintf(prompt, "Passphrase for key \"%.100s\": ", comment); - free(comment); - } - - if (ssh_get_password) { - if (!ssh_get_password(prompt, password, sizeof(password))) { - /* - * get_password failed to get a password (for - * example because one was supplied on the command - * line which has already failed to work). - * Terminate. - */ - logevent("No more passwords to try"); - ssh_state = SSH_STATE_CLOSED; - crReturn(1); - } - } else { - c_write(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: - random_save_seed(); - exit(0); - break; - default: - if (((c >= ' ' && c <= '~') || - ((unsigned char)c >= 160)) && pos < sizeof(password)) - password[pos++] = c; - break; - } - } - c_write("\r\n", 2); - } - - tryauth: - if (pwpkt_type == SSH1_CMSG_AUTH_RSA) { - /* - * Try public key authentication with the specified - * key file. - */ - static struct RSAKey pubkey; - static Bignum challenge, response; - static int i; - static unsigned char buffer[32]; - - tried_publickey = 1; - i = loadrsakey(cfg.keyfile, &pubkey, NULL, password); - if (i == 0) { - c_write("Couldn't load public key from ", 30); - c_write(cfg.keyfile, strlen(cfg.keyfile)); - c_write(".\r\n", 3); - continue; /* go and try password */ - } - if (i == -1) { - c_write("Wrong passphrase.\r\n", 19); - tried_publickey = 0; - continue; /* try again */ - } - - /* - * Send a public key attempt. - */ - send_packet(SSH1_CMSG_AUTH_RSA, - PKT_BIGNUM, pubkey.modulus, PKT_END); - - crWaitUntil(ispkt); - if (pktin.type == SSH1_SMSG_FAILURE) { - c_write("Server refused our public key.\r\n", 32); - 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 += 2) { - buffer[i] = response[16-i/2] >> 8; - buffer[i+1] = response[16-i/2] & 0xFF; - } - - MD5Init(&md5c); - MD5Update(&md5c, buffer, 32); - MD5Update(&md5c, session_id, 16); - MD5Final(buffer, &md5c); - - send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE, - PKT_DATA, buffer, 16, PKT_END); - - crWaitUntil(ispkt); - if (pktin.type == SSH1_SMSG_FAILURE) { - if (flags & FLAG_VERBOSE) - c_write("Failed to authenticate with our public key.\r\n", - 45); - continue; /* go and try password */ - } else if (pktin.type != SSH1_SMSG_SUCCESS) { - bombout(("Bizarre response to RSA authentication response")); - crReturn(0); - } - - break; /* we're through! */ - } else { - send_packet(pwpkt_type, PKT_STR, password, PKT_END); - } - logevent("Sent password"); - memset(password, 0, strlen(password)); + static int pwpkt_type; + /* + * Show password prompt, having first obtained it via a TIS + * or CryptoCard exchange if we're doing TIS or CryptoCard + * authentication. + */ + pwpkt_type = SSH1_CMSG_AUTH_PASSWORD; + if (agent_exists()) { + /* + * Attempt RSA authentication using Pageant. + */ + static unsigned char request[5], *response, *p; + static int responselen; + static int i, nkeys; + static int authed = FALSE; + void *r; + + logevent("Pageant is running. Requesting keys."); + + /* Request the keys held by the agent. */ + PUT_32BIT(request, 1); + request[4] = 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); + } + 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 (pktin.type == SSH1_SMSG_FAILURE && + cfg.try_tis_auth && + (supported_auths_mask & (1 << SSH1_AUTH_TIS))) { + 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"); + } 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[challengelen] = '\0'; + } + } + if (pktin.type == SSH1_SMSG_FAILURE && + cfg.try_tis_auth && + (supported_auths_mask & (1 << SSH1_AUTH_CCARD))) { + 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"); + } 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, "\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); + } + + 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 { + c_write_str(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: + random_save_seed(); + 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 public 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. + */ + if (ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) { + 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; + } + send_packet(pwpkt_type, PKT_INT, len, + PKT_DATA, s, len, PKT_END); + } else { + 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); + } + } + ssh_pkt_defersend(); + } + } 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("Access denied\r\n", 15); + 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; + ssh_state = SSH_STATE_CLOSED; crReturn(1); } else if (pktin.type != SSH1_SMSG_SUCCESS) { bombout(("Strange packet received, type %d", pktin.type)); - crReturn(0); + crReturn(0); } } @@ -1714,7 +2435,62 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) crFinish(1); } -static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { +void sshfwd_close(struct ssh_channel *c) +{ + if (c && !c->closes) { + 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->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(); @@ -1723,180 +2499,419 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { crReturnV; } if (ssh_state == SSH_STATE_CLOSED) - crReturnV; + 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"); + 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("Server refused to allocate pty\r\n", 32); - } + 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("Server refused to compress\r\n", 32); - } + 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(); } - if (*cfg.remote_cmd) - send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd, PKT_END); + if (*cfg.remote_cmd_ptr) + send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cfg.remote_cmd_ptr, + PKT_END); else - send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END); + 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); /* cause ldisc to notice changes */ ssh_send_ok = 1; ssh_channels = newtree234(ssh_channelcmp); - begin_session(); while (1) { crReturnV; if (ispkt) { if (pktin.type == SSH1_SMSG_STDOUT_DATA || - pktin.type == SSH1_SMSG_STDERR_DATA) { + pktin.type == SSH1_SMSG_STDERR_DATA) { long len = GET_32BIT(pktin.body); - from_backend(pktin.type == SSH1_SMSG_STDERR_DATA, - pktin.body+4, len); + int bufsize = + from_backend(pktin.type == SSH1_SMSG_STDERR_DATA, + pktin.body + 4, len); + if (bufsize > SSH1_BUFFER_LIMIT) { + ssh1_stdout_throttling = 1; + ssh1_throttle(+1); + } } else if (pktin.type == SSH1_MSG_DISCONNECT) { - ssh_state = SSH_STATE_CLOSED; + ssh_state = SSH_STATE_CLOSED; logevent("Received disconnect request"); - crReturnV; - } 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. */ - unsigned i; - struct ssh_channel *c; - enum234 e; + 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); + PKT_INT, GET_32BIT(pktin.body), PKT_END); } else { - i = 1; - for (c = first234(ssh_channels, &e); c; c = next234(&e)) { - if (c->localid > i) - break; /* found a free number */ - i = c->localid + 1; - } - c = malloc(sizeof(struct ssh_channel)); + c = smalloc(sizeof(struct ssh_channel)); c->remoteid = GET_32BIT(pktin.body); - c->localid = i; + c->localid = alloc_channel_id(); c->closes = 0; - c->type = SSH1_SMSG_AGENT_OPEN;/* identify channel type */ + 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; + pfd_confirm(c->u.pfd.s); + } + } 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); - send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END); - c->closes |= closetype; - if (c->closes == 3) { - del234(ssh_channels, c); - free(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) { - switch(c->type) { - case SSH1_SMSG_AGENT_OPEN: - /* 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 = malloc(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) - free(reply); - free(c->u.a.message); - c->u.a.lensofar = 0; - } - } - break; - } - } + /* 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 (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) { @@ -1906,7 +2921,7 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END); } else { bombout(("Strange packet received: type %d", pktin.type)); - crReturnV; + crReturnV; } } else { while (inlen > 0) { @@ -1925,48 +2940,51 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { /* * Utility routine for decoding comma-separated strings in KEXINIT. */ -static int in_commasep_string(char *needle, char *haystack, int haylen) { +static int in_commasep_string(char *needle, char *haystack, int haylen) +{ int needlen = strlen(needle); while (1) { - /* - * Is it at the start of the string? - */ - if (haylen >= needlen && /* haystack is long enough */ - !memcmp(needle, haystack, needlen) && /* initial match */ - (haylen == needlen || haystack[needlen] == ',') - /* either , or EOS follows */ - ) - return 1; - /* - * If not, search for the next comma and resume after that. - * If no comma found, terminate. - */ - while (haylen > 0 && *haystack != ',') - haylen--, haystack++; - if (haylen == 0) - return 0; - haylen--, haystack++; /* skip over comma itself */ + /* + * Is it at the start of the string? + */ + if (haylen >= needlen && /* haystack is long enough */ + !memcmp(needle, haystack, needlen) && /* initial match */ + (haylen == needlen || haystack[needlen] == ',') + /* either , or EOS follows */ + ) + return 1; + /* + * If not, search for the next comma and resume after that. + * If no comma found, terminate. + */ + while (haylen > 0 && *haystack != ',') + haylen--, haystack++; + if (haylen == 0) + return 0; + haylen--, haystack++; /* skip over comma itself */ } } /* * SSH2 key creation method. */ -static void ssh2_mkkey(Bignum K, char *H, char chr, char *keyspace) { +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, H, 20); + 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); + SHA_Final(&s, keyspace + 20); } /* @@ -1974,13 +2992,14 @@ static void ssh2_mkkey(Bignum K, char *H, char chr, char *keyspace) { */ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) { - static int i, len; + static int i, j, len, nbits, pbits; static char *str; - static Bignum e, f, K; + 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 ssh_cipher *cscipher_tobe = NULL; - static const struct ssh_cipher *sccipher_tobe = NULL; + 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; @@ -1990,25 +3009,29 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) static void *hkey; /* actual host key */ static unsigned char exchange_hash[20]; static unsigned char keyspace[40]; - static const struct ssh_cipher *preferred_cipher; + static const struct ssh2_ciphers *preferred_cipher; static const struct ssh_compress *preferred_comp; + static int first_kex; crBegin; random_init(); + first_kex = 1; /* * Set up the preferred cipher and compression. */ if (cfg.cipher == CIPHER_BLOWFISH) { - preferred_cipher = &ssh_blowfish_ssh2; + preferred_cipher = &ssh2_blowfish; } else if (cfg.cipher == CIPHER_DES) { - logevent("Single DES not supported in SSH2; using 3DES"); - preferred_cipher = &ssh_3des_ssh2; + logevent("Single DES not supported in SSH2; using 3DES"); + preferred_cipher = &ssh2_3des; } else if (cfg.cipher == CIPHER_3DES) { - preferred_cipher = &ssh_3des_ssh2; + preferred_cipher = &ssh2_3des; + } else if (cfg.cipher == CIPHER_AES) { + preferred_cipher = &ssh2_aes; } else { - /* Shouldn't happen, but we do want to initialise to _something_. */ - preferred_cipher = &ssh_3des_ssh2; + /* Shouldn't happen, but we do want to initialise to _something_. */ + preferred_cipher = &ssh2_3des; } if (cfg.compression) preferred_comp = &ssh_zlib; @@ -2018,77 +3041,85 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) /* * Be prepared to work around the buggy MAC problem. */ - if (cfg.buggymac) - maclist = buggymacs, nmacs = lenof(buggymacs); + if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC)) + maclist = buggymacs, nmacs = lenof(buggymacs); else - maclist = macs, nmacs = lenof(macs); + maclist = macs, nmacs = lenof(macs); - begin_key_exchange: + 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()); + 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(","); + 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(","); + ssh2_pkt_addstring_str(hostkey_algs[i]->name); + if (i < lenof(hostkey_algs) - 1) + ssh2_pkt_addstring_str(","); } /* List client->server encryption algorithms. */ ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(ciphers)+1; i++) { - const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1]; - ssh2_pkt_addstring_str(c->name); - if (i < lenof(ciphers)) - ssh2_pkt_addstring_str(","); + for (i = 0; i < lenof(ciphers) + 1; i++) { + const struct ssh2_ciphers *c = + i == 0 ? preferred_cipher : ciphers[i - 1]; + for (j = 0; j < c->nciphers; j++) { + ssh2_pkt_addstring_str(c->list[j]->name); + if (i < lenof(ciphers) || j < c->nciphers - 1) + ssh2_pkt_addstring_str(","); + } } /* List server->client encryption algorithms. */ ssh2_pkt_addstring_start(); - for (i = 0; i < lenof(ciphers)+1; i++) { - const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1]; - ssh2_pkt_addstring_str(c->name); - if (i < lenof(ciphers)) - ssh2_pkt_addstring_str(","); + for (i = 0; i < lenof(ciphers) + 1; i++) { + const struct ssh2_ciphers *c = + i == 0 ? preferred_cipher : ciphers[i - 1]; + for (j = 0; j < c->nciphers; j++) { + ssh2_pkt_addstring_str(c->list[j]->name); + if (i < lenof(ciphers) || j < c->nciphers - 1) + ssh2_pkt_addstring_str(","); + } } /* 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(","); + 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(","); + 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(","); + 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(","); + 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(); @@ -2098,105 +3129,167 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) ssh2_pkt_addbool(FALSE); /* Reserved. */ ssh2_pkt_adduint32(0); - sha_string(&exhash, pktout.data+5, pktout.length-5); + + 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); + 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); + 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 */ + 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; - } + 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; - } + if (in_commasep_string(hostkey_algs[i]->name, str, len)) { + hostkey = hostkey_algs[i]; + break; + } } ssh2_pkt_getstring(&str, &len); /* client->server cipher */ - for (i = 0; i < lenof(ciphers)+1; i++) { - const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1]; - if (in_commasep_string(c->name, str, len)) { - cscipher_tobe = c; - break; - } + for (i = 0; i < lenof(ciphers) + 1; i++) { + const struct ssh2_ciphers *c = + i == 0 ? preferred_cipher : ciphers[i - 1]; + 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) + break; } ssh2_pkt_getstring(&str, &len); /* server->client cipher */ - for (i = 0; i < lenof(ciphers)+1; i++) { - const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1]; - if (in_commasep_string(c->name, str, len)) { - sccipher_tobe = c; - break; - } + for (i = 0; i < lenof(ciphers) + 1; i++) { + const struct ssh2_ciphers *c = + i == 0 ? preferred_cipher : ciphers[i - 1]; + 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) + break; } 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; - } + 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; - } + 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; - } + 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; - } + 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; + } } /* - * Currently we only support Diffie-Hellman and DSS, so let's - * bomb out if those aren't selected. + * 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... */ - if (kex != &ssh_diffiehellman || hostkey != &ssh_dss) { - bombout(("internal fault: chaos in SSH 2 transport layer")); - crReturn(0); + { + 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; /* - * Now we begin the fun. Generate and send e for Diffie-Hellman. + * If we're doing Diffie-Hellman group exchange, start by + * requesting a group. */ - e = dh_create_e(); - ssh2_pkt_init(SSH2_MSG_KEXDH_INIT); + if (kex == &ssh_diffiehellman_gex) { + logevent("Doing Diffie-Hellman group exchange"); + /* + * 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 { + 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 != SSH2_MSG_KEXDH_REPLY) { - bombout(("expected key exchange packet from server")); - crReturn(0); + 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(); @@ -2205,22 +3298,28 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) 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:\r\n")); - for (i = 0; i < 20; i++) - debug((" %02x", exchange_hash[i])); - debug(("\r\n")); + debug(("Exchange hash is:\n")); + dmemdump(exchange_hash, 20); #endif hkey = hostkey->newkey(hostkeydata, hostkeylen); - if (!hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) { - bombout(("Server failed host key check")); - crReturn(0); + if (!hkey || + !hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) { + bombout(("Server's host key did not match the signature supplied")); + crReturn(0); } /* @@ -2228,8 +3327,8 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) */ crWaitUntil(ispkt); if (pktin.type != SSH2_MSG_NEWKEYS) { - bombout(("expected new-keys packet from server")); - crReturn(0); + bombout(("expected new-keys packet from server")); + crReturn(0); } /* @@ -2239,11 +3338,13 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) keystr = hostkey->fmtkey(hkey); fingerprint = hostkey->fingerprint(hkey); verify_ssh_host_key(savedhost, savedport, hostkey->keytype, - keystr, fingerprint); - logevent("Host key fingerprint is:"); - logevent(fingerprint); - free(fingerprint); - free(keystr); + 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); /* @@ -2264,14 +3365,36 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) cscomp->compress_init(); sccomp->decompress_init(); /* - * Set IVs after keys. + * Set IVs after keys. Here we use the exchange hash from the + * _first_ key exchange. */ - ssh2_mkkey(K, exchange_hash, 'C', keyspace); cscipher->setcskey(keyspace); - ssh2_mkkey(K, exchange_hash, 'D', keyspace); cscipher->setsckey(keyspace); - ssh2_mkkey(K, exchange_hash, 'A', keyspace); cscipher->setcsiv(keyspace); - ssh2_mkkey(K, exchange_hash, 'B', keyspace); sccipher->setsciv(keyspace); - ssh2_mkkey(K, exchange_hash, 'E', keyspace); csmac->setcskey(keyspace); - ssh2_mkkey(K, exchange_hash, 'F', keyspace); scmac->setsckey(keyspace); + if (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 @@ -2279,21 +3402,94 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) * transport. If we ever see a KEXINIT, we must go back to the * start. */ - do { - crReturn(1); - } while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)); + while (!(ispkt && 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) +{ + 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 unsigned long remote_winsize; - static unsigned long remote_maxpkt; + 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 char pwprompt[200]; + static char password[100]; crBegin; @@ -2305,133 +3501,697 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) ssh2_pkt_send(); crWaitUntilV(ispkt); if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) { - bombout(("Server refused user authentication protocol")); - crReturnV; + bombout(("Server refused user authentication protocol")); + crReturnV; } /* - * FIXME: currently we support only password authentication. - * (This places us technically in violation of the SSH2 spec. - * We must fix this.) + * 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! */ - while (1) { - /* - * Get a username and a password. - */ - static char username[100]; - static char password[100]; - static int pos = 0; + do { + static int pos; static char c; + /* + * Get a username. + */ + pos = 0; if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { - c_write("login as: ", 10); - 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("\b \b", 3); - pos--; - } - break; - case 21: case 27: - while (pos > 0) { - c_write("\b \b", 3); - pos--; - } - break; - case 3: case 4: - random_save_seed(); - exit(0); - break; - default: - if (((c >= ' ' && c <= '~') || - ((unsigned char)c >= 160)) && pos < 40) { - username[pos++] = c; - c_write(&c, 1); - } - break; + if (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: + random_save_seed(); + 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("\r\n", 2); + 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)) { + if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) { sprintf(stuff, "Using username \"%s\".\r\n", username); - c_write(stuff, strlen(stuff)); + c_write_str(stuff); } } - if (ssh_get_password) { - char prompt[200]; - sprintf(prompt, "%.90s@%.90s's password: ", username, savedhost); - if (!ssh_get_password(prompt, password, sizeof(password))) { - /* - * get_password failed to get a password (for - * example because one was supplied on the command - * line which has already failed to work). - * Terminate. - */ - logevent("No more passwords to try"); - ssh_state = SSH_STATE_CLOSED; - crReturnV; - } - } else { - c_write("password: ", 10); - 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: - random_save_seed(); - exit(0); - break; - default: - if (((c >= ' ' && c <= '~') || - ((unsigned char)c >= 160)) && pos < 40) - password[pos++] = c; - break; - } - } - c_write("\r\n", 2); - } + /* + * 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. + */ + 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; + + 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; + } - ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST); - ssh2_pkt_addstring(username); - ssh2_pkt_addstring("ssh-connection"); /* service requested */ - ssh2_pkt_addstring("password"); - ssh2_pkt_addbool(FALSE); - ssh2_pkt_addstring(password); - ssh2_pkt_send(); - - crWaitUntilV(ispkt); - if (pktin.type != SSH2_MSG_USERAUTH_SUCCESS) { - c_write("Access denied\r\n", 15); - logevent("Authentication refused"); - } else - 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_passwd = + in_commasep_string("password", methods, methlen); + can_keyb_inter = + in_commasep_string("keyboard-interactive", methods, methlen); + } + + method = 0; + + if (!method && can_keyb_inter && !tried_keyb_inter) { + method = AUTH_KEYBOARD_INTERACTIVE; + type = AUTH_TYPE_KEYBOARD_INTERACTIVE; + tried_keyb_inter = TRUE; + + 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; + + /* 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)); + need_pw = TRUE; + + echo = ssh2_pkt_getbool(); + } + } + + 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; + + 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; + 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; + + /* + * 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_passwd) { + method = AUTH_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: + random_save_seed(); + 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 { + 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; + } + } + } while (!we_are_in); /* * Now we're authenticated for the connection protocol. The @@ -2442,218 +4202,604 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) /* * So now create a channel with a session in it. */ - mainchan = malloc(sizeof(struct ssh_channel)); - mainchan->localid = 100; /* as good as any */ + 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); - ssh2_pkt_adduint32(0x8000UL); /* our window size */ - ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */ + 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 */ + 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; + bombout(("Server's channel confirmation cited wrong channel")); + crReturnV; } mainchan->remoteid = ssh2_pkt_getuint32(); - mainchan->u.v2.remwindow = ssh2_pkt_getuint32(); - mainchan->u.v2.remmaxpkt = ssh2_pkt_getuint32(); - mainchan->u.v2.outbuffer = NULL; - mainchan->u.v2.outbuflen = mainchan->u.v2.outbufsize = 0; + 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"); /* + * 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(); + + 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(("Server got confused by X11 forwarding request")); + crReturnV; + } + logevent("X11 forwarding refused"); + } else { + logevent("X11 forwarding enabled"); + ssh_X11_fwd_enabled = TRUE; + } + } + + /* + * Enable port forwardings. + */ + { + static char *e; /* preserve across crReturn */ + char type; + int n; + int sport,dport; + char sports[256], dports[256], host[256]; + char buf[1024]; + + 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 */ + 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(("Server got confused by port forwarding request")); + crReturnV; + } + logevent("Server refused this port forwarding"); + } else { + logevent("Remote port forwarding enabled"); + } + } + } + } + } + } + + /* + * Potentially enable agent forwarding. + */ + if (cfg.agentfwd && agent_exists()) { + logevent("Requesting OpenSSH-style agent forwarding"); + ssh2_pkt_init(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( + ("Server got confused by agent forwarding request")); + crReturnV; + } + logevent("Agent forwarding refused"); + } else { + logevent("Agent forwarding enabled"); + ssh_agentfwd_enabled = TRUE; + } + } + + /* * Now allocate a pty for the session. */ 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) { - /* FIXME: be able to handle other channels here */ - if (ssh2_pkt_getuint32() != mainchan->localid) - continue; /* wrong channel */ - mainchan->u.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(("Server got confused by pty request")); - crReturnV; - } - c_write("Server refused to allocate pty\r\n", 32); - } else { - logevent("Allocated pty"); - } + 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(("Server got confused by pty request")); + 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; } /* * Start a shell or a remote command. */ ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST); - ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */ - if (*cfg.remote_cmd) { - ssh2_pkt_addstring("exec"); - ssh2_pkt_addbool(1); /* want reply */ - ssh2_pkt_addstring(cfg.remote_cmd); + ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */ + if (cfg.ssh_subsys) { + ssh2_pkt_addstring("subsystem"); + ssh2_pkt_addbool(1); /* want reply */ + ssh2_pkt_addstring(cfg.remote_cmd_ptr); + } else if (*cfg.remote_cmd_ptr) { + ssh2_pkt_addstring("exec"); + ssh2_pkt_addbool(1); /* want reply */ + ssh2_pkt_addstring(cfg.remote_cmd_ptr); } else { - ssh2_pkt_addstring("shell"); - ssh2_pkt_addbool(1); /* want reply */ + ssh2_pkt_addstring("shell"); + ssh2_pkt_addbool(1); /* want reply */ } ssh2_pkt_send(); do { - crWaitUntilV(ispkt); - if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { - /* FIXME: be able to handle other channels here */ - if (ssh2_pkt_getuint32() != mainchan->localid) - continue; /* wrong channel */ - mainchan->u.v2.remwindow += ssh2_pkt_getuint32(); - } + 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(("Server got confused by shell/command request")); - crReturnV; - } - bombout(("Server refused to start a shell/command")); - crReturnV; + if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) { + bombout(("Server got confused by shell/command request")); + crReturnV; + } + bombout(("Server refused to start a shell/command")); + crReturnV; } else { - logevent("Started a shell/command"); + logevent("Started a shell/command"); } ssh_state = SSH_STATE_SESSION; if (size_needed) ssh_size(); + if (eof_needed) + ssh_special(TS_EOF); /* * Transfer data! */ + ldisc_send(NULL, 0); /* cause ldisc to notice changes */ ssh_send_ok = 1; - begin_session(); while (1) { - static int try_send; + static int try_send; crReturnV; - try_send = FALSE; + try_send = FALSE; if (ispkt) { if (pktin.type == SSH2_MSG_CHANNEL_DATA || - pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) { - char *data; - int length; - /* FIXME: be able to handle other channels here */ - if (ssh2_pkt_getuint32() != mainchan->localid) - continue; /* wrong channel */ - if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA && - ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR) - continue; /* extended but not stderr */ - ssh2_pkt_getstring(&data, &length); - if (data) { - from_backend(pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA, - data, length); - /* - * Enlarge the window again at the remote side, - * just in case it ever runs down and they fail - * to send us any more data. - */ - ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST); - ssh2_pkt_adduint32(mainchan->remoteid); - ssh2_pkt_adduint32(length); - ssh2_pkt_send(); - } + 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; + ssh_state = SSH_STATE_CLOSED; logevent("Received disconnect message"); - crReturnV; + crReturnV; } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) { - continue; /* exit status et al; ignore (FIXME?) */ + continue; /* exit status et al; ignore (FIXME?) */ } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) { - continue; /* remote sends EOF; ignore */ + 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) { - /* FIXME: be able to handle other channels here */ - if (ssh2_pkt_getuint32() != mainchan->localid) - continue; /* wrong channel */ - ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); - ssh2_pkt_adduint32(mainchan->remoteid); - ssh2_pkt_send(); - /* FIXME: mark the channel as closed */ - if (1 /* FIXME: "all channels are closed" */) { - 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(); - ssh_state = SSH_STATE_CLOSED; - crReturnV; - } - continue; /* remote sends close; ignore (FIXME) */ + unsigned i = ssh2_pkt_getuint32(); + struct ssh_channel *c; + + c = find234(ssh_channels, &i, ssh_channelfind); + if (!c) + continue; /* nonexistent channel */ + if (c->closes == 0) { + ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE); + ssh2_pkt_adduint32(c->remoteid); + ssh2_pkt_send(); + } + /* Do pre-close processing on the channel. */ + switch (c->type) { + case CHAN_MAINSESSION: + break; /* nothing to see here, move along */ + case CHAN_X11: + break; + case CHAN_AGENT: + break; + case CHAN_SOCKDATA: + break; + } + 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) { + 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(); + ssh_state = SSH_STATE_CLOSED; + crReturnV; + } + continue; /* remote sends close; ignore (FIXME) */ } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) { - /* FIXME: be able to handle other channels here */ - if (ssh2_pkt_getuint32() != mainchan->localid) - continue; /* wrong channel */ - mainchan->u.v2.remwindow += ssh2_pkt_getuint32(); - try_send = TRUE; + 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->closes = 0; + c->v.v2.remwindow = ssh2_pkt_getuint32(); + c->v.v2.remmaxpkt = ssh2_pkt_getuint32(); + bufchain_init(&c->v.v2.outbuffer); + pfd_confirm(c->u.pfd.s); + } 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; + crReturnV; } } else { - /* - * We have spare data. Add it to the channel buffer. - */ - if (mainchan->u.v2.outbufsize < - mainchan->u.v2.outbuflen + inlen) { - mainchan->u.v2.outbufsize = - mainchan->u.v2.outbuflen + inlen + 1024; - mainchan->u.v2.outbuffer = srealloc(mainchan->u.v2.outbuffer, - mainchan->u.v2.outbufsize); - } - memcpy(mainchan->u.v2.outbuffer + mainchan->u.v2.outbuflen, - in, inlen); - mainchan->u.v2.outbuflen += inlen; - try_send = TRUE; + /* + * 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; + } + } + } } - if (try_send) { - /* - * Try to send data on the channel if we can. (FIXME: - * on _all_ channels.) - */ - while (mainchan->u.v2.remwindow > 0 && - mainchan->u.v2.outbuflen > 0) { - unsigned len = mainchan->u.v2.remwindow; - if (len > mainchan->u.v2.outbuflen) - len = mainchan->u.v2.outbuflen; - if (len > mainchan->u.v2.remmaxpkt) - len = mainchan->u.v2.remmaxpkt; - ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA); - ssh2_pkt_adduint32(mainchan->remoteid); - ssh2_pkt_addstring_start(); - ssh2_pkt_addstring_data(mainchan->u.v2.outbuffer, len); - ssh2_pkt_send(); - mainchan->u.v2.outbuflen -= len; - memmove(mainchan->u.v2.outbuffer, mainchan->u.v2.outbuffer+len, - mainchan->u.v2.outbuflen); - mainchan->u.v2.remwindow -= len; - } - } } crFinishV; @@ -2665,7 +4811,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) static void ssh2_protocol(unsigned char *in, int inlen, int ispkt) { if (do_ssh2_transport(in, inlen, ispkt) == 0) - return; + return; do_ssh2_authconn(in, inlen, ispkt); } @@ -2674,15 +4820,20 @@ static void ssh2_protocol(unsigned char *in, int inlen, int ispkt) * * Returns an error message, or NULL on success. */ -static char *ssh_init (char *host, int port, char **realhost) { +static char *ssh_init(char *host, int port, char **realhost) +{ char *p; - + #ifdef MSCRYPTOAPI - if(crypto_startup() == 0) + if (crypto_startup() == 0) return "Microsoft high encryption pack not installed!"; #endif ssh_send_ok = 0; + ssh_editing = 0; + ssh_echoing = 0; + ssh1_throttle_count = 0; + ssh_overall_bufsize = 0; p = connect_to_host(host, port, realhost); if (p != NULL) @@ -2694,42 +4845,78 @@ static char *ssh_init (char *host, int port, char **realhost) { /* * Called to send data down the Telnet connection. */ -static void ssh_send (char *buf, int len) { +static int ssh_send(char *buf, int len) +{ if (s == NULL || ssh_protocol == NULL) - return; + 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 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: - 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(); - } - } + 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; } } @@ -2738,39 +4925,139 @@ static void ssh_size(void) { * can send an EOF and collect resulting output (e.g. `plink * hostname sort'). */ -static void ssh_special (Telnet_Special code) { +static void ssh_special(Telnet_Special code) +{ if (code == TS_EOF) { - if (ssh_version == 1) { - send_packet(SSH1_CMSG_EOF, PKT_END); - } else { - ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF); - ssh2_pkt_adduint32(mainchan->remoteid); - ssh2_pkt_send(); - } - logevent("Sent EOF message"); + 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_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(); - } + 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; +} + +/* + * This is called when stdout/stderr (the entity to which + * from_backend sends data) manages to clear some backlog. + */ +void ssh_unthrottle(int bufsize) +{ + if (ssh_version == 1) { + if (bufsize < SSH1_BUFFER_LIMIT) { + ssh1_stdout_throttling = 0; + ssh1_throttle(-1); + } } else { - /* do nothing */ + if (mainchan && mainchan->closes == 0) + ssh2_set_window(mainchan, OUR_V2_WINSIZE - bufsize); } } -static Socket ssh_socket(void) { return s; } +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_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; +} Backend ssh_backend = { ssh_init, ssh_send, + ssh_sendbuffer, ssh_size, ssh_special, ssh_socket, ssh_sendok, + ssh_ldisc, + ssh_unthrottle, 22 };