X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/7d503c31cbea063f19c830295662e12be44640e2..ff89646a8828ce862d53b96a19ee6469dabce71a:/ssh.c diff --git a/ssh.c b/ssh.c index 801f67f9..f48d1426 100644 --- a/ssh.c +++ b/ssh.c @@ -17,7 +17,7 @@ #define logevent(s) { logevent(s); \ if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \ - fprintf(stderr, "%s\n", s); } + { fprintf(stderr, "%s\n", s); fflush(stderr); } } #define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \ (s ? sk_close(s), s = NULL : 0), \ @@ -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 */ @@ -114,6 +118,29 @@ #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 */ @@ -179,9 +206,7 @@ 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 }; @@ -202,10 +227,12 @@ static int ssh_comp_none_block(unsigned char *block, int len, unsigned char **outblock, int *outlen) { return 0; } +static int ssh_comp_none_disable(void) { return 0; } const static struct ssh_compress ssh_comp_none = { "none", ssh_comp_none_init, ssh_comp_none_block, - ssh_comp_none_init, ssh_comp_none_block + ssh_comp_none_init, ssh_comp_none_block, + ssh_comp_none_disable }; extern const struct ssh_compress ssh_zlib; const static struct ssh_compress *compressions[] = { @@ -256,6 +283,8 @@ 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; @@ -269,7 +298,8 @@ 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; @@ -335,6 +365,42 @@ static int ssh_channelfind(void *av, void *bv) { return 0; } +static int alloc_channel_id(void) { + const unsigned CHANNEL_NUMBER_OFFSET = 256; + unsigned low, high, mid; + int tsize; + struct ssh_channel *c; + + /* + * First-fit allocation of channel numbers: always pick the + * lowest unused one. To do this, binary-search using the + * counted B-tree to find the largest channel ID which is in a + * contiguous sequence from the beginning. (Precisely + * everything in that sequence must have ID equal to its tree + * index plus CHANNEL_NUMBER_OFFSET.) + */ + tsize = count234(ssh_channels); + + low = -1; high = tsize; + while (high - low > 1) { + mid = (high + low) / 2; + c = index234(ssh_channels, mid); + if (c->localid == mid + CHANNEL_NUMBER_OFFSET) + low = mid; /* this one is fine */ + else + high = mid; /* this one is past it */ + } + /* + * Now low points to either -1, or the tree index of the + * largest ID in the initial sequence. + */ + { + unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET; + assert(NULL == find234(ssh_channels, &i, ssh_channelfind)); + } + return low + 1 + CHANNEL_NUMBER_OFFSET; +} + static void c_write (char *buf, int len) { if ((flags & FLAG_STDERR)) { int i; @@ -346,6 +412,16 @@ 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)); } @@ -431,11 +507,13 @@ 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); @@ -452,10 +530,13 @@ 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 } @@ -488,6 +569,20 @@ 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); } @@ -627,6 +722,28 @@ next_packet: if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG) 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); } @@ -906,7 +1023,7 @@ static void ssh2_pkt_addstring(char *data) { } static char *ssh2_mpint_fmt(Bignum b, int *len) { unsigned char *p; - int i, n = (ssh1_bignum_bitcount(b)+7)/8; + int i, n = (bignum_bitcount(b)+7)/8; p = smalloc(n + 1); if (!p) fatalbox("out of memory"); @@ -1106,7 +1223,9 @@ 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; @@ -1134,10 +1253,11 @@ 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; @@ -1157,13 +1277,18 @@ 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'; @@ -1178,11 +1303,13 @@ static int do_ssh_init(unsigned char c) { 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 @@ -1192,18 +1319,19 @@ 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], 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(vstring, "%s\n", verstring); sprintf(vlog, "We claim version: %s", verstring); logevent(vlog); + strcat(verstring, "\n"); logevent("Using SSH protocol version 2"); - sk_write(s, vstring, strlen(vstring)); + sk_write(s, verstring, strlen(verstring)); ssh_protocol = ssh2_protocol; ssh_version = 2; s_rdpkt = ssh2_rdpkt; @@ -1211,19 +1339,23 @@ 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(vlog, "We claim version: %s", vstring); - vlog[strcspn(vlog, "\r\n")] = '\0'; + 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, vstring, strlen(vstring)); + 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); } @@ -1269,21 +1401,20 @@ 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) { @@ -1302,6 +1433,11 @@ 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 @@ -1339,7 +1475,7 @@ 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; @@ -1401,9 +1537,13 @@ 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); @@ -1465,6 +1605,11 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) if ((supported_ciphers_mask & (1 << cipher_type)) == 0) { 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; @@ -1477,7 +1622,7 @@ 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..."); @@ -1503,43 +1648,56 @@ 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'; } @@ -1590,7 +1748,8 @@ 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); @@ -1630,7 +1789,7 @@ static int do_ssh1_login(unsigned char *in, int inlen, int ispkt) PUT_32BIT(agentreq, len); q = agentreq + 4; *q++ = SSH1_AGENTC_RSA_CHALLENGE; - PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus)); + PUT_32BIT(q, bignum_bitcount(key.modulus)); q += 4; q += ssh1_write_bignum(q, key.exponent); q += ssh1_write_bignum(q, key.modulus); @@ -1741,13 +1900,12 @@ 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; @@ -1911,7 +2069,7 @@ 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; @@ -1965,7 +2123,7 @@ 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 { @@ -2024,10 +2182,16 @@ 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")); @@ -2076,8 +2240,8 @@ 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"); @@ -2106,9 +2270,7 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { } 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. */ - unsigned i; - struct ssh_channel *c, *d; - enum234 e; + struct ssh_channel *c; logevent("Received X11 connect request"); /* Refuse if X11 forwarding is disabled. */ @@ -2128,13 +2290,8 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { PKT_END); } else { logevent("opening X11 forward connection succeeded"); - for (i=1, d = first234(ssh_channels, &e); d; d = next234(&e)) { - if (d->localid > i) - break; /* found a free number */ - i = d->localid + 1; - } c->remoteid = GET_32BIT(pktin.body); - c->localid = i; + c->localid = alloc_channel_id(); c->closes = 0; c->type = CHAN_X11; /* identify channel type */ add234(ssh_channels, c); @@ -2147,9 +2304,7 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { } 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; /* Refuse if agent forwarding is disabled. */ if (!ssh_agentfwd_enabled) { @@ -2157,15 +2312,9 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { 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 = smalloc(sizeof(struct ssh_channel)); c->remoteid = GET_32BIT(pktin.body); - c->localid = i; + c->localid = alloc_channel_id(); c->closes = 0; c->type = CHAN_AGENT; /* identify channel type */ c->u.a.lensofar = 0; @@ -2183,7 +2332,8 @@ static void ssh1_protocol(unsigned char *in, int inlen, int ispkt) { if (c) { int closetype; closetype = (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2); - send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END); + if (!(c->closes & closetype)) + send_packet(pktin.type, PKT_INT, c->remoteid, PKT_END); if ((c->closes == 0) && (c->type == CHAN_X11)) { logevent("X11 connection closed"); assert(c->u.x11.s != NULL); @@ -2329,7 +2479,7 @@ 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; @@ -2552,30 +2702,34 @@ 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); @@ -2598,7 +2752,7 @@ 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(); @@ -2616,7 +2770,7 @@ 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); } @@ -2839,40 +2993,53 @@ 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 { @@ -2909,7 +3076,21 @@ 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) { @@ -2921,6 +3102,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) { bombout(("Strange packet received during authentication: type %d", pktin.type)); + crReturnV; } gotit = FALSE; @@ -2982,7 +3164,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) method = 0; - if (!method && can_pubkey && agent_exists && !tried_agent) { + if (!method && can_pubkey && agent_exists() && !tried_agent) { /* * Attempt public-key authentication using Pageant. */ @@ -3001,7 +3183,8 @@ 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); @@ -3037,9 +3220,11 @@ 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. @@ -3154,13 +3339,14 @@ 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; @@ -3347,8 +3533,9 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) /* * So now create a channel with a session in it. */ + ssh_channels = newtree234(ssh_channelcmp); mainchan = smalloc(sizeof(struct ssh_channel)); - mainchan->localid = 100; /* as good as any */ + mainchan->localid = alloc_channel_id(); ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN); ssh2_pkt_addstring("session"); ssh2_pkt_adduint32(mainchan->localid); @@ -3372,7 +3559,6 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) mainchan->v2.remmaxpkt = ssh2_pkt_getuint32(); mainchan->v2.outbuffer = NULL; mainchan->v2.outbuflen = mainchan->v2.outbufsize = 0; - ssh_channels = newtree234(ssh_channelcmp); add234(ssh_channels, mainchan); logevent("Opened channel for session"); @@ -3421,9 +3607,7 @@ 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"); @@ -3506,11 +3690,11 @@ 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 */ @@ -3653,7 +3837,6 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) { unsigned i = ssh2_pkt_getuint32(); struct ssh_channel *c; - enum234 e; c = find234(ssh_channels, &i, ssh_channelfind); if (!c) @@ -3679,8 +3862,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) /* * See if that was the last channel left open. */ - c = first234(ssh_channels, &e); - if (!c) { + if (count234(ssh_channels) == 0) { logevent("All channels closed. Disconnecting"); ssh2_pkt_init(SSH2_MSG_DISCONNECT); ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION); @@ -3697,7 +3879,7 @@ 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; @@ -3737,17 +3919,7 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) ssh2_pkt_send(); sfree(c); } else { - struct ssh_channel *d; - unsigned i; - enum234 e; - - for (i=1, d = first234(ssh_channels, &e); d; - d = next234(&e)) { - if (d->localid > i) - break; /* found a free number */ - i = d->localid + 1; - } - c->localid = i; + c->localid = alloc_channel_id(); c->closes = 0; c->v2.remwindow = ssh2_pkt_getuint32(); c->v2.remmaxpkt = ssh2_pkt_getuint32(); @@ -3773,12 +3945,12 @@ static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt) try_send = TRUE; } if (try_send) { - enum234 e; + int i; struct ssh_channel *c; /* * Try to send data on all channels if we can. */ - for (c = first234(ssh_channels, &e); c; c = next234(&e)) + for (i = 0; NULL != (c = index234(ssh_channels, i)); i++) ssh2_try_send(c); } }