X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/63b00c83637c5c4f20bb6e4fb9ec2fb906d3c8a2..50526e4712f04d911b20f45259e545e726d7377a:/ssh.c diff --git a/ssh.c b/ssh.c index ea1fe02a..1d328ae2 100644 --- a/ssh.c +++ b/ssh.c @@ -68,6 +68,10 @@ #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 */ @@ -179,9 +183,7 @@ const static struct ssh2_ciphers *ciphers[] = { }; const static struct ssh_kex *kex_algs[] = { -#ifdef DO_DIFFIE_HELLMAN_GEX &ssh_diffiehellman_gex, -#endif &ssh_diffiehellman }; const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss }; @@ -258,6 +260,8 @@ 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; @@ -271,7 +275,8 @@ static const struct ssh_compress *sccomp = NULL; static const struct ssh_kex *kex = NULL; static const struct ssh_signkey *hostkey = NULL; static unsigned char ssh2_session_id[20]; -int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = NULL; +int (*ssh_get_line)(const char *prompt, char *str, int maxlen, + int is_pw) = NULL; static char *savedhost; static int savedport; @@ -348,6 +353,16 @@ static void c_write (char *buf, int len) { 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)); } @@ -433,11 +448,13 @@ next_packet: unsigned char *decompblk; int decomplen; #if 0 - int i; - debug(("Packet payload pre-decompression:\n")); - for (i = -1; i < pktin.length; i++) - debug((" %02x", (unsigned char)pktin.body[i])); - debug(("\r\n")); + { + int i; + debug(("Packet payload pre-decompression:\n")); + for (i = -1; i < pktin.length; i++) + debug((" %02x", (unsigned char)pktin.body[i])); + debug(("\r\n")); + } #endif zlib_decompress_block(pktin.body-1, pktin.length+1, &decompblk, &decomplen); @@ -454,10 +471,13 @@ next_packet: sfree(decompblk); pktin.length = decomplen-1; #if 0 - debug(("Packet payload post-decompression:\n")); - for (i = -1; i < pktin.length; i++) - debug((" %02x", (unsigned char)pktin.body[i])); - debug(("\r\n")); + { + int i; + debug(("Packet payload post-decompression:\n")); + for (i = -1; i < pktin.length; i++) + debug((" %02x", (unsigned char)pktin.body[i])); + debug(("\r\n")); + } #endif } @@ -1136,10 +1156,11 @@ static void ssh_detect_bugs(char *vstring) { } static int do_ssh_init(unsigned char c) { - static char *vsp; + static char 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; @@ -1159,13 +1180,18 @@ static int do_ssh_init(unsigned char c) { 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'; @@ -1180,7 +1206,11 @@ static int do_ssh_init(unsigned char c) { ssh_agentfwd_enabled = FALSE; rdpkt2_state.incoming_sequence = 0; - *vsp = 0; + vstring[vslen] = 0; + if (vslen > 80) + vlog = smalloc(20 + vslen); + else + vlog = smalloc(100); sprintf(vlog, "Server version: %s", vstring); ssh_detect_bugs(vstring); vlog[strcspn(vlog, "\r\n")] = '\0'; @@ -1194,7 +1224,8 @@ static int do_ssh_init(unsigned char c) { /* * This is a v2 server. Begin v2 protocol. */ - char *verstring = "SSH-2.0-PuTTY"; + char verstring[80]; + sprintf(verstring, "SSH-2.0-%s", sshver); SHA_Init(&exhashbase); /* * Hash our version string and their version string. @@ -1213,8 +1244,9 @@ static int do_ssh_init(unsigned char c) { /* * This is a v1 server. Begin v1 protocol. */ - sprintf(vstring, "SSH-%s-PuTTY\n", - (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5")); + sprintf(vstring, "SSH-%s-%s\n", + (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"), + sshver); sprintf(vlog, "We claim version: %s", vstring); vlog[strcspn(vlog, "\r\n")] = '\0'; logevent(vlog); @@ -1226,6 +1258,9 @@ static int do_ssh_init(unsigned char c) { } ssh_state = SSH_STATE_BEFORE_SIZE; + sfree(vstring); + sfree(vlog); + crFinish(0); } @@ -1271,21 +1306,20 @@ static void ssh_gotdata(unsigned char *data, int datalen) crFinishV; } -static int ssh_receive(Socket skt, int urgent, char *data, int len) { - if (urgent==3) { +static int ssh_closing (Plug plug, char *error_msg, int error_code, int calling_back) { + ssh_state = SSH_STATE_CLOSED; + sk_close(s); + s = NULL; + if (error_msg) { /* A socket error has occurred. */ - ssh_state = SSH_STATE_CLOSED; - sk_close(s); - s = NULL; - connection_fatal(data); - return 0; - } else if (!len) { - /* Connection has closed. */ - ssh_state = SSH_STATE_CLOSED; - sk_close(s); - s = NULL; - return 0; + connection_fatal (error_msg); + } else { + /* Otherwise, the remote side closed the connection normally. */ } + return 0; +} + +static int ssh_receive(Plug plug, int urgent, char *data, int len) { ssh_gotdata (data, len); if (ssh_state == SSH_STATE_CLOSED) { if (s) { @@ -1304,6 +1338,11 @@ static int ssh_receive(Socket skt, int urgent, char *data, int len) { */ static char *connect_to_host(char *host, int port, char **realhost) { + static struct plug_function_table fn_table = { + ssh_closing, + ssh_receive + }, *fn_table_ptr = &fn_table; + SockAddr addr; char *err; #ifdef FWHACK @@ -1341,7 +1380,7 @@ static char *connect_to_host(char *host, int port, char **realhost) /* * Open socket. */ - s = sk_new(addr, port, 0, 1, ssh_receive); + s = sk_new(addr, port, 0, 1, &fn_table_ptr); if ( (err = sk_socket_error(s)) ) return err; @@ -1403,9 +1442,13 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) logevent(logmsg); } + ssh1_remote_protoflags = GET_32BIT(pktin.body+8+i+j); supported_ciphers_mask = GET_32BIT(pktin.body+12+i+j); supported_auths_mask = GET_32BIT(pktin.body+16+i+j); + ssh1_local_protoflags = ssh1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED; + ssh1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER; + MD5Init(&md5c); MD5Update(&md5c, keystr2, hostkey.bytes); MD5Update(&md5c, keystr1, servkey.bytes); @@ -1479,7 +1522,7 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) PKT_DATA, cookie, 8, PKT_CHAR, (len*8) >> 8, PKT_CHAR, (len*8) & 0xFF, PKT_DATA, rsabuf, len, - PKT_INT, 0, + PKT_INT, ssh1_local_protoflags, PKT_END); logevent("Trying to enable encryption..."); @@ -1505,43 +1548,56 @@ 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_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 < 40) { - username[pos++] = c; - c_write(&c, 1); - } - break; - } - } - c_write_str("\r\n"); - username[strcspn(username, "\n\r")] = '\0'; - } else { + 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 < 40) { + username[pos++] = c; + c_write(&c, 1); + } + break; + } + } + c_write_str("\r\n"); + username[strcspn(username, "\n\r")] = '\0'; + } + } else { strncpy(username, cfg.username, 99); username[99] = '\0'; } @@ -1592,7 +1648,8 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES; agent_query(request, 5, &r, &responselen); response = (unsigned char *)r; - if (response) { + 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); @@ -1743,13 +1800,12 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) sfree(comment); } - if (ssh_get_password) { - if (!ssh_get_password(prompt, password, sizeof(password))) { + if (ssh_get_line) { + if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) { /* - * get_password failed to get a password (for - * example because one was supplied on the command - * line which has already failed to work). - * Terminate. + * get_line 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; @@ -1913,7 +1969,7 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) pwlen = strlen(password); if (pwlen < 16) { - bottom = 1; + bottom = 0; /* zero length passwords are OK! :-) */ top = 15; } else { bottom = pwlen &~ 7; @@ -1967,7 +2023,7 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) } void sshfwd_close(struct ssh_channel *c) { - if (c) { + if (c && !c->closes) { if (ssh_version == 1) { send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid, PKT_END); } else { @@ -2026,10 +2082,16 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { char proto[20], data[64]; logevent("Requesting X11 forwarding"); x11_invent_auth(proto, sizeof(proto), data, sizeof(data)); - send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING, - PKT_STR, proto, PKT_STR, data, - PKT_INT, 0, - PKT_END); + 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")); @@ -2078,8 +2140,8 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { 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); logevent("Started session"); @@ -2331,7 +2393,7 @@ static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr, char *keyspace */ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) { - static int i, j, len, nbits; + static int i, j, len, nbits, pbits; static char *str; static Bignum p, g, e, f, K; static int kex_init_value, kex_reply_value; @@ -2554,30 +2616,34 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) } /* + * Work out the number of bits of key we will need from the key + * exchange. We start with the maximum key length of either + * cipher... + */ + { + int csbits, scbits; + + csbits = cscipher_tobe->keylen; + scbits = sccipher_tobe->keylen; + nbits = (csbits > scbits ? csbits : scbits); + } + /* The keys only have 160-bit entropy, since they're based on + * a SHA-1 hash. So cap the key size at 160 bits. */ + if (nbits > 160) nbits = 160; + + /* * If we're doing Diffie-Hellman group exchange, start by * requesting a group. */ if (kex == &ssh_diffiehellman_gex) { - int csbits, scbits; - logevent("Doing Diffie-Hellman group exchange"); /* - * Work out number of bits. We start with the maximum key - * length of either cipher... - */ - 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; - /* - * ... and then work out how big a DH group we will need to - * allow that much data. - */ - nbits = 512 << ((nbits-1) / 64); + * 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(nbits); + ssh2_pkt_adduint32(pbits); ssh2_pkt_send(); crWaitUntil(ispkt); @@ -2600,7 +2666,7 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) /* * Now generate and send e for Diffie-Hellman. */ - e = dh_create_e(); + e = dh_create_e(nbits*2); ssh2_pkt_init(kex_init_value); ssh2_pkt_addmp(e); ssh2_pkt_send(); @@ -2618,7 +2684,7 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt) sha_string(&exhash, hostkeydata, hostkeylen); if (kex == &ssh_diffiehellman_gex) { - sha_uint32(&exhash, nbits); + sha_uint32(&exhash, pbits); sha_mpint(&exhash, p); sha_mpint(&exhash, g); } @@ -2841,40 +2907,53 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) */ pos = 0; if ((flags & FLAG_INTERACTIVE) && !*cfg.username) { - 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 < 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 < 40) { + username[pos++] = c; + c_write(&c, 1); + } + break; + } + } + } c_write_str("\r\n"); username[strcspn(username, "\n\r")] = '\0'; } else { @@ -2911,7 +2990,21 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) if (!gotit) crWaitUntilV(ispkt); while (pktin.type == SSH2_MSG_USERAUTH_BANNER) { - /* FIXME: should support this */ + 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) { @@ -3003,7 +3096,8 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) request[4] = SSH2_AGENTC_REQUEST_IDENTITIES; agent_query(request, 5, &r, &responselen); response = (unsigned char *)r; - if (response) { + 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); @@ -3039,9 +3133,11 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) continue; } - c_write_str("Authenticating with public key \""); - c_write(commentp, commentlen); - c_write_str("\" from agent\r\n"); + 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. @@ -3156,13 +3252,14 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) } if (need_pw) { - if (ssh_get_password) { - if (!ssh_get_password(pwprompt, password, sizeof(password))) { + if (ssh_get_line) { + if (!ssh_get_line(pwprompt, password, + sizeof(password), TRUE)) { /* - * get_password failed to get a password (for - * example because one was supplied on the command - * line which has already failed to work). - * Terminate. + * get_line 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; @@ -3423,9 +3520,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) * Potentially enable agent forwarding. */ if (cfg.agentfwd && agent_exists()) { - char proto[20], data[64]; logevent("Requesting OpenSSH-style agent 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("auth-agent-req@openssh.com"); @@ -3508,11 +3603,11 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) if (cfg.ssh_subsys) { ssh2_pkt_addstring("subsystem"); ssh2_pkt_addbool(1); /* want reply */ - ssh2_pkt_addstring(cfg.remote_cmd); - } else if (*cfg.remote_cmd) { + 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); + ssh2_pkt_addstring(cfg.remote_cmd_ptr); } else { ssh2_pkt_addstring("shell"); ssh2_pkt_addbool(1); /* want reply */ @@ -3699,7 +3794,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) c = find234(ssh_channels, &i, ssh_channelfind); if (!c) continue; /* nonexistent channel */ - mainchan->v2.remwindow += ssh2_pkt_getuint32(); + c->v2.remwindow += ssh2_pkt_getuint32(); try_send = TRUE; } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) { char *type;