projects / u / mdw / putty / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
Three more patches from RDB: one to make Atomica work right, one to
[u/mdw/putty] / ssh.c
CommitLineData
8df7a775 1#include <windows.h>
374330e2 2#include <stdio.h>
3#include <stdlib.h>
fb09bf1c 4#include <stdarg.h>
5#include <assert.h>
374330e2 6
7#include "putty.h"
dacbd0e8 8#include "tree234.h"
fb09bf1c 9#include "ssh.h"
374330e2 10
11#ifndef FALSE
12#define FALSE 0
13#endif
14#ifndef TRUE
15#define TRUE 1
16#endif
17
765c4200 18/* uncomment this for packet level debugging */
19/* #define DUMP_PACKETS */
20
fb09bf1c 21#define logevent(s) { logevent(s); \
67779be7 22 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
b4453f49 23 { fprintf(stderr, "%s\n", s); fflush(stderr); } }
fb09bf1c 24
3cd52910 25#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \
4a8fc3c4 26 (s ? sk_close(s), s = NULL : 0), \
3cd52910 27 connection_fatal msg )
8d5de777 28
32874aea 29#define SSH1_MSG_DISCONNECT 1 /* 0x1 */
30#define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
31#define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
32#define SSH1_CMSG_USER 4 /* 0x4 */
33#define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
34#define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
35#define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
36#define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
37#define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
38#define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
39#define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
40#define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
41#define SSH1_SMSG_SUCCESS 14 /* 0xe */
42#define SSH1_SMSG_FAILURE 15 /* 0xf */
43#define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
44#define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
45#define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
46#define SSH1_CMSG_EOF 19 /* 0x13 */
47#define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
48#define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
49#define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
50#define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
51#define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
52#define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
53#define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
54#define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
55#define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
56#define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
57#define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
58#define SSH1_MSG_IGNORE 32 /* 0x20 */
59#define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
60#define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
61#define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
62#define SSH1_MSG_DEBUG 36 /* 0x24 */
63#define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
64#define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
65#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
66#define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
67#define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
68#define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
69#define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
70
71#define SSH1_AUTH_TIS 5 /* 0x5 */
72#define SSH1_AUTH_CCARD 16 /* 0x10 */
73
74#define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
b96dc54c 75/* Mask for protoflags we will echo back to server if seen */
32874aea 76#define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
77
78#define SSH2_MSG_DISCONNECT 1 /* 0x1 */
79#define SSH2_MSG_IGNORE 2 /* 0x2 */
80#define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
81#define SSH2_MSG_DEBUG 4 /* 0x4 */
82#define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
83#define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
84#define SSH2_MSG_KEXINIT 20 /* 0x14 */
85#define SSH2_MSG_NEWKEYS 21 /* 0x15 */
86#define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
87#define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
88#define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
89#define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
90#define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
91#define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
92#define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
93#define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
94#define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
95#define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
96#define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
97#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
761187b6 98#define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
99#define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
32874aea 100#define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
101#define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
102#define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
103#define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
104#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
105#define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
106#define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
107#define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
108#define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
109#define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
110#define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
111#define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
112#define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
113#define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
114
115#define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
116#define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
117#define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
118#define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
119#define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
120#define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
121#define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
122#define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
123#define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
124#define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
125#define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
126#define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
127#define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
128#define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
129#define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
38c4a8da 130
131static const char *const ssh2_disconnect_reasons[] = {
132 NULL,
133 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
134 "SSH_DISCONNECT_PROTOCOL_ERROR",
135 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
136 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
137 "SSH_DISCONNECT_MAC_ERROR",
138 "SSH_DISCONNECT_COMPRESSION_ERROR",
139 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
140 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
141 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
142 "SSH_DISCONNECT_CONNECTION_LOST",
143 "SSH_DISCONNECT_BY_APPLICATION",
144 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
145 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
146 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
147 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
148};
9005f3ba 149
32874aea 150#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
151#define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
152#define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
153#define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
d211621f 154
32874aea 155#define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
fb09bf1c 156
7d503c31 157/*
158 * Various remote-bug flags.
159 */
160#define BUG_CHOKES_ON_SSH1_IGNORE 1
161#define BUG_SSH2_HMAC 2
162
fb09bf1c 163#define GET_32BIT(cp) \
164 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
165 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
166 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
167 ((unsigned long)(unsigned char)(cp)[3]))
168
169#define PUT_32BIT(cp, value) { \
170 (cp)[0] = (unsigned char)((value) >> 24); \
171 (cp)[1] = (unsigned char)((value) >> 16); \
172 (cp)[2] = (unsigned char)((value) >> 8); \
173 (cp)[3] = (unsigned char)(value); }
174
7cca0d81 175enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
972a41c8 176
374330e2 177/* Coroutine mechanics for the sillier bits of the code */
178#define crBegin1 static int crLine = 0;
179#define crBegin2 switch(crLine) { case 0:;
180#define crBegin crBegin1; crBegin2;
181#define crFinish(z) } crLine = 0; return (z)
182#define crFinishV } crLine = 0; return
183#define crReturn(z) \
184 do {\
185 crLine=__LINE__; return (z); case __LINE__:;\
186 } while (0)
187#define crReturnV \
188 do {\
189 crLine=__LINE__; return; case __LINE__:;\
190 } while (0)
191#define crStop(z) do{ crLine = 0; return (z); }while(0)
192#define crStopV do{ crLine = 0; return; }while(0)
fb09bf1c 193#define crWaitUntil(c) do { crReturn(0); } while (!(c))
7cca0d81 194#define crWaitUntilV(c) do { crReturnV; } while (!(c))
374330e2 195
32874aea 196extern char *x11_init(Socket *, char *, void *);
197extern void x11_close(Socket);
5471d09a 198extern int x11_send(Socket, char *, int);
9c964e85 199extern void x11_invent_auth(char *, int, char *, int);
5471d09a 200extern void x11_unthrottle(Socket s);
201extern void x11_override_throttle(Socket s, int enable);
9c964e85 202
d74d141c 203extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c);
204extern char *pfd_addforward(char *desthost, int destport, int port);
205extern void pfd_close(Socket s);
5471d09a 206extern int pfd_send(Socket s, char *data, int len);
d74d141c 207extern void pfd_confirm(Socket s);
5471d09a 208extern void pfd_unthrottle(Socket s);
209extern void pfd_override_throttle(Socket s, int enable);
210
211/*
212 * Buffer management constants. There are several of these for
213 * various different purposes:
214 *
215 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
216 * on a local data stream before we throttle the whole SSH
217 * connection (in SSH1 only). Throttling the whole connection is
218 * pretty drastic so we set this high in the hope it won't
219 * happen very often.
220 *
221 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
222 * on the SSH connection itself before we defensively throttle
223 * _all_ local data streams. This is pretty drastic too (though
224 * thankfully unlikely in SSH2 since the window mechanism should
225 * ensure that the server never has any need to throttle its end
226 * of the connection), so we set this high as well.
227 *
228 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
229 * channels.
230 */
231
232#define SSH1_BUFFER_LIMIT 32768
233#define SSH_MAX_BACKLOG 32768
234#define OUR_V2_WINSIZE 16384
d74d141c 235
5e8358ad 236/*
237 * Ciphers for SSH2. We miss out single-DES because it isn't
238 * supported; also 3DES and Blowfish are both done differently from
239 * SSH1. (3DES uses outer chaining; Blowfish has the opposite
240 * endianness and different-sized keys.)
5e8358ad 241 */
0a3f1d48 242const static struct ssh2_ciphers *ciphers[] = {
243 &ssh2_aes,
244 &ssh2_blowfish,
245 &ssh2_3des,
8479e33c 246};
e5574168 247
a92dd380 248const static struct ssh_kex *kex_algs[] = {
a92dd380 249 &ssh_diffiehellman_gex,
32874aea 250 &ssh_diffiehellman
251};
e5574168 252
85cc02bb 253const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
e5574168 254
32874aea 255static void nullmac_key(unsigned char *key)
256{
257}
258static void nullmac_generate(unsigned char *blk, int len,
259 unsigned long seq)
260{
261}
262static int nullmac_verify(unsigned char *blk, int len, unsigned long seq)
263{
264 return 1;
265}
57476f6b 266const static struct ssh_mac ssh_mac_none = {
d39f364a 267 nullmac_key, nullmac_key, nullmac_generate, nullmac_verify, "none", 0
e5574168 268};
8b2715b2 269const static struct ssh_mac *macs[] = {
32874aea 270 &ssh_sha1, &ssh_md5, &ssh_mac_none
271};
8b2715b2 272const static struct ssh_mac *buggymacs[] = {
32874aea 273 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
274};
e5574168 275
32874aea 276static void ssh_comp_none_init(void)
277{
278}
4ba9b64b 279static int ssh_comp_none_block(unsigned char *block, int len,
32874aea 280 unsigned char **outblock, int *outlen)
281{
282 return 0;
283}
284static int ssh_comp_none_disable(void)
285{
4ba9b64b 286 return 0;
287}
57476f6b 288const static struct ssh_compress ssh_comp_none = {
4ba9b64b 289 "none",
290 ssh_comp_none_init, ssh_comp_none_block,
63b00c83 291 ssh_comp_none_init, ssh_comp_none_block,
292 ssh_comp_none_disable
e5574168 293};
4ba9b64b 294extern const struct ssh_compress ssh_zlib;
295const static struct ssh_compress *compressions[] = {
32874aea 296 &ssh_zlib, &ssh_comp_none
297};
374330e2 298
32874aea 299enum { /* channel types */
783415f8 300 CHAN_MAINSESSION,
301 CHAN_X11,
302 CHAN_AGENT,
bc240b21 303 CHAN_SOCKDATA,
304 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
783415f8 305};
306
dacbd0e8 307/*
308 * 2-3-4 tree storing channels.
309 */
310struct ssh_channel {
d211621f 311 unsigned remoteid, localid;
dacbd0e8 312 int type;
313 int closes;
5471d09a 314 union {
315 struct ssh1_data_channel {
316 int throttling;
317 } v1;
318 struct ssh2_data_channel {
319 bufchain outbuffer;
320 unsigned remwindow, remmaxpkt;
321 unsigned locwindow;
322 } v2;
323 } v;
dacbd0e8 324 union {
32874aea 325 struct ssh_agent_channel {
326 unsigned char *message;
327 unsigned char msglen[4];
328 int lensofar, totallen;
329 } a;
330 struct ssh_x11_channel {
331 Socket s;
332 } x11;
d74d141c 333 struct ssh_pfd_channel {
334 Socket s;
335 } pfd;
dacbd0e8 336 } u;
337};
57476f6b 338
d74d141c 339/*
bc240b21 340 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
341 * 2 use this structure in different ways, reflecting SSH 2's
342 * altogether saner approach to port forwarding.
343 *
344 * In SSH 1, you arrange a remote forwarding by sending the server
345 * the remote port number, and the local destination host:port.
346 * When a connection comes in, the server sends you back that
347 * host:port pair, and you connect to it. This is a ready-made
348 * security hole if you're not on the ball: a malicious server
349 * could send you back _any_ host:port pair, so if you trustingly
350 * connect to the address it gives you then you've just opened the
351 * entire inside of your corporate network just by connecting
352 * through it to a dodgy SSH server. Hence, we must store a list of
353 * host:port pairs we _are_ trying to forward to, and reject a
354 * connection request from the server if it's not in the list.
355 *
356 * In SSH 2, each side of the connection minds its own business and
357 * doesn't send unnecessary information to the other. You arrange a
358 * remote forwarding by sending the server just the remote port
359 * number. When a connection comes in, the server tells you which
360 * of its ports was connected to; and _you_ have to remember what
361 * local host:port pair went with that port number.
362 *
363 * Hence: in SSH 1 this structure stores host:port pairs we intend
364 * to allow connections to, and is indexed by those host:port
365 * pairs. In SSH 2 it stores a mapping from source port to
366 * destination host:port pair, and is indexed by source port.
d74d141c 367 */
368struct ssh_rportfwd {
bc240b21 369 unsigned sport, dport;
370 char dhost[256];
d74d141c 371};
372
57476f6b 373struct Packet {
374 long length;
375 int type;
376 unsigned char *data;
377 unsigned char *body;
378 long savedpos;
379 long maxlen;
380};
381
0db56f73 382static SHA_State exhash, exhashbase;
57476f6b 383
8df7a775 384static Socket s = NULL;
57476f6b 385
386static unsigned char session_key[32];
4ba9b64b 387static int ssh1_compressing;
b96dc54c 388static int ssh1_remote_protoflags;
389static int ssh1_local_protoflags;
db7d555c 390static int ssh_agentfwd_enabled;
9c964e85 391static int ssh_X11_fwd_enabled;
7d503c31 392static int ssh_remote_bugs;
57476f6b 393static const struct ssh_cipher *cipher = NULL;
0a3f1d48 394static const struct ssh2_cipher *cscipher = NULL;
395static const struct ssh2_cipher *sccipher = NULL;
57476f6b 396static const struct ssh_mac *csmac = NULL;
397static const struct ssh_mac *scmac = NULL;
398static const struct ssh_compress *cscomp = NULL;
399static const struct ssh_compress *sccomp = NULL;
400static const struct ssh_kex *kex = NULL;
e055a386 401static const struct ssh_signkey *hostkey = NULL;
65a22376 402static unsigned char ssh2_session_id[20];
32874aea 403int (*ssh_get_line) (const char *prompt, char *str, int maxlen,
404 int is_pw) = NULL;
57476f6b 405
406static char *savedhost;
407static int savedport;
408static int ssh_send_ok;
0965bee0 409static int ssh_echoing, ssh_editing;
57476f6b 410
32874aea 411static tree234 *ssh_channels; /* indexed by local id */
57476f6b 412static struct ssh_channel *mainchan; /* primary session channel */
413
d74d141c 414static tree234 *ssh_rportfwds;
415
57476f6b 416static enum {
3687d221 417 SSH_STATE_PREPACKET,
57476f6b 418 SSH_STATE_BEFORE_SIZE,
419 SSH_STATE_INTERMED,
420 SSH_STATE_SESSION,
421 SSH_STATE_CLOSED
3687d221 422} ssh_state = SSH_STATE_PREPACKET;
57476f6b 423
3687d221 424static int size_needed = FALSE, eof_needed = FALSE;
57476f6b 425
426static struct Packet pktin = { 0, 0, NULL, NULL, 0 };
427static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
b185170a 428static unsigned char *deferred_send_data = NULL;
429static int deferred_len = 0, deferred_size = 0;
57476f6b 430
fd5e5847 431/*
432 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
433 * that fails. This variable is the means by which scp.c can reach
434 * into the SSH code and find out which one it got.
435 */
436int ssh_fallback_cmd = 0;
437
57476f6b 438static int ssh_version;
5471d09a 439static int ssh1_throttle_count;
440static int ssh_overall_bufsize;
441static int ssh_throttled_all;
442static int ssh1_stdout_throttling;
32874aea 443static void (*ssh_protocol) (unsigned char *in, int inlen, int ispkt);
57476f6b 444static void ssh1_protocol(unsigned char *in, int inlen, int ispkt);
445static void ssh2_protocol(unsigned char *in, int inlen, int ispkt);
446static void ssh_size(void);
32874aea 447static void ssh_special(Telnet_Special);
5471d09a 448static int ssh2_try_send(struct ssh_channel *c);
32874aea 449static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
450 int len);
5471d09a 451static void ssh_throttle_all(int enable, int bufsize);
452static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
32874aea 453static int (*s_rdpkt) (unsigned char **data, int *datalen);
5471d09a 454static int ssh_sendbuffer(void);
57476f6b 455
456static struct rdpkt1_state_tag {
457 long len, pad, biglen, to_read;
458 unsigned long realcrc, gotcrc;
459 unsigned char *p;
460 int i;
461 int chunk;
462} rdpkt1_state;
463
960e736a 464static struct rdpkt2_state_tag {
465 long len, pad, payload, packetlen, maclen;
466 int i;
467 int cipherblk;
468 unsigned long incoming_sequence;
469} rdpkt2_state;
470
32874aea 471static int ssh_channelcmp(void *av, void *bv)
472{
473 struct ssh_channel *a = (struct ssh_channel *) av;
474 struct ssh_channel *b = (struct ssh_channel *) bv;
475 if (a->localid < b->localid)
476 return -1;
477 if (a->localid > b->localid)
478 return +1;
dacbd0e8 479 return 0;
480}
32874aea 481static int ssh_channelfind(void *av, void *bv)
482{
483 unsigned *a = (unsigned *) av;
484 struct ssh_channel *b = (struct ssh_channel *) bv;
485 if (*a < b->localid)
486 return -1;
487 if (*a > b->localid)
488 return +1;
dacbd0e8 489 return 0;
490}
491
bc240b21 492static int ssh_rportcmp_ssh1(void *av, void *bv)
d74d141c 493{
494 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
495 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
496 int i;
bc240b21 497 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
d74d141c 498 return i < 0 ? -1 : +1;
bc240b21 499 if (a->dport > b->dport)
500 return +1;
501 if (a->dport < b->dport)
502 return -1;
503 return 0;
504}
505
506static int ssh_rportcmp_ssh2(void *av, void *bv)
507{
508 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
509 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
cdcbdf3b 510
bc240b21 511 if (a->sport > b->sport)
d74d141c 512 return +1;
bc240b21 513 if (a->sport < b->sport)
514 return -1;
d74d141c 515 return 0;
516}
517
32874aea 518static int alloc_channel_id(void)
519{
260f3dec 520 const unsigned CHANNEL_NUMBER_OFFSET = 256;
521 unsigned low, high, mid;
d2371c81 522 int tsize;
523 struct ssh_channel *c;
524
525 /*
526 * First-fit allocation of channel numbers: always pick the
527 * lowest unused one. To do this, binary-search using the
528 * counted B-tree to find the largest channel ID which is in a
529 * contiguous sequence from the beginning. (Precisely
530 * everything in that sequence must have ID equal to its tree
531 * index plus CHANNEL_NUMBER_OFFSET.)
532 */
533 tsize = count234(ssh_channels);
534
32874aea 535 low = -1;
536 high = tsize;
d2371c81 537 while (high - low > 1) {
538 mid = (high + low) / 2;
539 c = index234(ssh_channels, mid);
540 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
541 low = mid; /* this one is fine */
542 else
543 high = mid; /* this one is past it */
544 }
545 /*
546 * Now low points to either -1, or the tree index of the
547 * largest ID in the initial sequence.
548 */
549 {
550 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
551 assert(NULL == find234(ssh_channels, &i, ssh_channelfind));
552 }
553 return low + 1 + CHANNEL_NUMBER_OFFSET;
554}
555
32874aea 556static void c_write(char *buf, int len)
557{
67779be7 558 if ((flags & FLAG_STDERR)) {
32874aea 559 int i;
560 for (i = 0; i < len; i++)
561 if (buf[i] != '\r')
562 fputc(buf[i], stderr);
fb09bf1c 563 return;
564 }
fe50e814 565 from_backend(1, buf, len);
3bdaf79d 566}
567
32874aea 568static void c_write_untrusted(char *buf, int len)
569{
a209e957 570 int i;
571 for (i = 0; i < len; i++) {
32874aea 572 if (buf[i] == '\n')
573 c_write("\r\n", 2);
574 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
575 c_write(buf + i, 1);
a209e957 576 }
577}
578
32874aea 579static void c_write_str(char *buf)
580{
1408a877 581 c_write(buf, strlen(buf));
582}
583
fb09bf1c 584/*
585 * Collect incoming data in the incoming packet buffer.
e5574168 586 * Decipher and verify the packet when it is completely read.
587 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
fb09bf1c 588 * Update the *data and *datalen variables.
589 * Return the additional nr of bytes needed, or 0 when
590 * a complete packet is available.
591 */
e5574168 592static int ssh1_rdpkt(unsigned char **data, int *datalen)
fb09bf1c 593{
57476f6b 594 struct rdpkt1_state_tag *st = &rdpkt1_state;
374330e2 595
596 crBegin;
374330e2 597
32874aea 598 next_packet:
37508af4 599
fb09bf1c 600 pktin.type = 0;
601 pktin.length = 0;
374330e2 602
57476f6b 603 for (st->i = st->len = 0; st->i < 4; st->i++) {
fb09bf1c 604 while ((*datalen) == 0)
32874aea 605 crReturn(4 - st->i);
57476f6b 606 st->len = (st->len << 8) + **data;
fb09bf1c 607 (*data)++, (*datalen)--;
608 }
374330e2 609
fb09bf1c 610#ifdef FWHACK
32874aea 611 if (st->len == 0x52656d6f) { /* "Remo"te server has closed ... */
612 st->len = 0x300; /* big enough to carry to end */
fb09bf1c 613 }
614#endif
374330e2 615
57476f6b 616 st->pad = 8 - (st->len % 8);
617 st->biglen = st->len + st->pad;
618 pktin.length = st->len - 5;
fb09bf1c 619
57476f6b 620 if (pktin.maxlen < st->biglen) {
621 pktin.maxlen = st->biglen;
32874aea 622 pktin.data = (pktin.data == NULL ? smalloc(st->biglen + APIEXTRA) :
623 srealloc(pktin.data, st->biglen + APIEXTRA));
fb09bf1c 624 if (!pktin.data)
625 fatalbox("Out of memory");
626 }
374330e2 627
57476f6b 628 st->to_read = st->biglen;
629 st->p = pktin.data;
630 while (st->to_read > 0) {
32874aea 631 st->chunk = st->to_read;
fb09bf1c 632 while ((*datalen) == 0)
57476f6b 633 crReturn(st->to_read);
634 if (st->chunk > (*datalen))
635 st->chunk = (*datalen);
636 memcpy(st->p, *data, st->chunk);
637 *data += st->chunk;
638 *datalen -= st->chunk;
639 st->p += st->chunk;
640 st->to_read -= st->chunk;
fb09bf1c 641 }
374330e2 642
fb09bf1c 643 if (cipher)
57476f6b 644 cipher->decrypt(pktin.data, st->biglen);
765c4200 645#ifdef DUMP_PACKETS
646 debug(("Got packet len=%d pad=%d\n", st->len, st->pad));
647 dmemdump(pktin.data, st->biglen);
698a5108 648#endif
374330e2 649
32874aea 650 st->realcrc = crc32(pktin.data, st->biglen - 4);
651 st->gotcrc = GET_32BIT(pktin.data + st->biglen - 4);
57476f6b 652 if (st->gotcrc != st->realcrc) {
8d5de777 653 bombout(("Incorrect CRC received on packet"));
32874aea 654 crReturn(0);
fb09bf1c 655 }
572f871e 656
4ba9b64b 657 pktin.body = pktin.data + st->pad + 1;
658
659 if (ssh1_compressing) {
660 unsigned char *decompblk;
661 int decomplen;
765c4200 662#ifdef DUMP_PACKETS
663 debug(("Packet payload pre-decompression:\n"));
32874aea 664 dmemdump(pktin.body - 1, pktin.length + 1);
4ba9b64b 665#endif
32874aea 666 zlib_decompress_block(pktin.body - 1, pktin.length + 1,
4ba9b64b 667 &decompblk, &decomplen);
668
669 if (pktin.maxlen < st->pad + decomplen) {
670 pktin.maxlen = st->pad + decomplen;
32874aea 671 pktin.data = srealloc(pktin.data, pktin.maxlen + APIEXTRA);
672 pktin.body = pktin.data + st->pad + 1;
4ba9b64b 673 if (!pktin.data)
674 fatalbox("Out of memory");
675 }
676
32874aea 677 memcpy(pktin.body - 1, decompblk, decomplen);
dcbde236 678 sfree(decompblk);
32874aea 679 pktin.length = decomplen - 1;
765c4200 680#ifdef DUMP_PACKETS
681 debug(("Packet payload post-decompression:\n"));
32874aea 682 dmemdump(pktin.body - 1, pktin.length + 1);
4ba9b64b 683#endif
684 }
685
e5574168 686 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
32874aea 687 pktin.type == SSH1_SMSG_STDERR_DATA ||
688 pktin.type == SSH1_MSG_DEBUG ||
689 pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
690 pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
fb09bf1c 691 long strlen = GET_32BIT(pktin.body);
8d5de777 692 if (strlen + 4 != pktin.length) {
693 bombout(("Received data packet with bogus string length"));
32874aea 694 crReturn(0);
695 }
fb09bf1c 696 }
697
4ba9b64b 698 pktin.type = pktin.body[-1];
699
e5574168 700 if (pktin.type == SSH1_MSG_DEBUG) {
fb09bf1c 701 /* log debug message */
702 char buf[80];
703 int strlen = GET_32BIT(pktin.body);
704 strcpy(buf, "Remote: ");
32874aea 705 if (strlen > 70)
706 strlen = 70;
707 memcpy(buf + 8, pktin.body + 4, strlen);
708 buf[8 + strlen] = '\0';
fb09bf1c 709 logevent(buf);
710 goto next_packet;
e5574168 711 } else if (pktin.type == SSH1_MSG_IGNORE) {
fb09bf1c 712 /* do nothing */
713 goto next_packet;
714 }
715
38c4a8da 716 if (pktin.type == SSH1_MSG_DISCONNECT) {
717 /* log reason code in disconnect message */
718 char buf[256];
260f3dec 719 unsigned msglen = GET_32BIT(pktin.body);
720 unsigned nowlen;
38c4a8da 721 strcpy(buf, "Remote sent disconnect: ");
722 nowlen = strlen(buf);
32874aea 723 if (msglen > sizeof(buf) - nowlen - 1)
724 msglen = sizeof(buf) - nowlen - 1;
725 memcpy(buf + nowlen, pktin.body + 4, msglen);
726 buf[nowlen + msglen] = '\0';
38c4a8da 727 logevent(buf);
4eb195cc 728 bombout(("Server sent disconnect message:\n\"%s\"", buf+nowlen));
e14d0f19 729 crReturn(0);
38c4a8da 730 }
731
fb09bf1c 732 crFinish(0);
733}
734
e5574168 735static int ssh2_rdpkt(unsigned char **data, int *datalen)
736{
960e736a 737 struct rdpkt2_state_tag *st = &rdpkt2_state;
e5574168 738
739 crBegin;
740
32874aea 741 next_packet:
e5574168 742 pktin.type = 0;
743 pktin.length = 0;
960e736a 744 if (sccipher)
32874aea 745 st->cipherblk = sccipher->blksize;
e5574168 746 else
32874aea 747 st->cipherblk = 8;
960e736a 748 if (st->cipherblk < 8)
32874aea 749 st->cipherblk = 8;
960e736a 750
751 if (pktin.maxlen < st->cipherblk) {
752 pktin.maxlen = st->cipherblk;
32874aea 753 pktin.data =
754 (pktin.data ==
755 NULL ? smalloc(st->cipherblk +
756 APIEXTRA) : srealloc(pktin.data,
757 st->cipherblk +
758 APIEXTRA));
e5574168 759 if (!pktin.data)
760 fatalbox("Out of memory");
761 }
762
763 /*
764 * Acquire and decrypt the first block of the packet. This will
765 * contain the length and padding details.
766 */
32874aea 767 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
e5574168 768 while ((*datalen) == 0)
32874aea 769 crReturn(st->cipherblk - st->i);
960e736a 770 pktin.data[st->i] = *(*data)++;
32874aea 771 (*datalen)--;
e5574168 772 }
773#ifdef FWHACK
32874aea 774 if (!memcmp(pktin.data, "Remo", 4)) { /* "Remo"te server has closed ... */
775 /* FIXME */
e5574168 776 }
777#endif
778 if (sccipher)
32874aea 779 sccipher->decrypt(pktin.data, st->cipherblk);
e5574168 780
781 /*
782 * Now get the length and padding figures.
783 */
960e736a 784 st->len = GET_32BIT(pktin.data);
785 st->pad = pktin.data[4];
e5574168 786
787 /*
788 * This enables us to deduce the payload length.
789 */
960e736a 790 st->payload = st->len - st->pad - 1;
e5574168 791
960e736a 792 pktin.length = st->payload + 5;
e5574168 793
794 /*
795 * So now we can work out the total packet length.
796 */
960e736a 797 st->packetlen = st->len + 4;
798 st->maclen = scmac ? scmac->len : 0;
e5574168 799
800 /*
801 * Adjust memory allocation if packet is too big.
802 */
32874aea 803 if (pktin.maxlen < st->packetlen + st->maclen) {
804 pktin.maxlen = st->packetlen + st->maclen;
805 pktin.data =
806 (pktin.data ==
807 NULL ? smalloc(pktin.maxlen + APIEXTRA) : srealloc(pktin.data,
808 pktin.maxlen
809 +
810 APIEXTRA));
e5574168 811 if (!pktin.data)
812 fatalbox("Out of memory");
813 }
814
815 /*
816 * Read and decrypt the remainder of the packet.
817 */
32874aea 818 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
819 st->i++) {
e5574168 820 while ((*datalen) == 0)
960e736a 821 crReturn(st->packetlen + st->maclen - st->i);
822 pktin.data[st->i] = *(*data)++;
32874aea 823 (*datalen)--;
e5574168 824 }
825 /* Decrypt everything _except_ the MAC. */
826 if (sccipher)
32874aea 827 sccipher->decrypt(pktin.data + st->cipherblk,
828 st->packetlen - st->cipherblk);
e5574168 829
765c4200 830#ifdef DUMP_PACKETS
831 debug(("Got packet len=%d pad=%d\n", st->len, st->pad));
832 dmemdump(pktin.data, st->packetlen);
7cca0d81 833#endif
d39f364a 834
e5574168 835 /*
836 * Check the MAC.
837 */
32874aea 838 if (scmac
839 && !scmac->verify(pktin.data, st->len + 4,
840 st->incoming_sequence)) {
8d5de777 841 bombout(("Incorrect MAC received on packet"));
32874aea 842 crReturn(0);
8d5de777 843 }
32874aea 844 st->incoming_sequence++; /* whether or not we MACed */
e5574168 845
4ba9b64b 846 /*
847 * Decompress packet payload.
848 */
849 {
850 unsigned char *newpayload;
851 int newlen;
32874aea 852 if (sccomp && sccomp->decompress(pktin.data + 5, pktin.length - 5,
4ba9b64b 853 &newpayload, &newlen)) {
32874aea 854 if (pktin.maxlen < newlen + 5) {
855 pktin.maxlen = newlen + 5;
856 pktin.data =
857 (pktin.data ==
858 NULL ? smalloc(pktin.maxlen +
859 APIEXTRA) : srealloc(pktin.data,
860 pktin.maxlen +
861 APIEXTRA));
4ba9b64b 862 if (!pktin.data)
863 fatalbox("Out of memory");
864 }
865 pktin.length = 5 + newlen;
32874aea 866 memcpy(pktin.data + 5, newpayload, newlen);
765c4200 867#ifdef DUMP_PACKETS
868 debug(("Post-decompression payload:\n"));
32874aea 869 dmemdump(pktin.data + 5, newlen);
4ba9b64b 870#endif
871
dcbde236 872 sfree(newpayload);
4ba9b64b 873 }
874 }
875
e5574168 876 pktin.savedpos = 6;
877 pktin.type = pktin.data[5];
e5574168 878
7cca0d81 879 if (pktin.type == SSH2_MSG_IGNORE || pktin.type == SSH2_MSG_DEBUG)
32874aea 880 goto next_packet; /* FIXME: print DEBUG message */
e5574168 881
38c4a8da 882 if (pktin.type == SSH2_MSG_DISCONNECT) {
883 /* log reason code in disconnect message */
884 char buf[256];
32874aea 885 int reason = GET_32BIT(pktin.data + 6);
886 unsigned msglen = GET_32BIT(pktin.data + 10);
260f3dec 887 unsigned nowlen;
38c4a8da 888 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
889 sprintf(buf, "Received disconnect message (%s)",
890 ssh2_disconnect_reasons[reason]);
891 } else {
32874aea 892 sprintf(buf, "Received disconnect message (unknown type %d)",
893 reason);
38c4a8da 894 }
895 logevent(buf);
896 strcpy(buf, "Disconnection message text: ");
897 nowlen = strlen(buf);
32874aea 898 if (msglen > sizeof(buf) - nowlen - 1)
899 msglen = sizeof(buf) - nowlen - 1;
900 memcpy(buf + nowlen, pktin.data + 14, msglen);
901 buf[nowlen + msglen] = '\0';
38c4a8da 902 logevent(buf);
4eb195cc 903 bombout(("Server sent disconnect message\ntype %d (%s):\n\"%s\"",
904 reason,
905 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
906 ssh2_disconnect_reasons[reason] : "unknown",
907 buf+nowlen));
e14d0f19 908 crReturn(0);
38c4a8da 909 }
910
e5574168 911 crFinish(0);
912}
913
32874aea 914static void ssh1_pktout_size(int len)
915{
374330e2 916 int pad, biglen;
917
918 len += 5; /* type and CRC */
32874aea 919 pad = 8 - (len % 8);
374330e2 920 biglen = len + pad;
921
32874aea 922 pktout.length = len - 5;
374330e2 923 if (pktout.maxlen < biglen) {
924 pktout.maxlen = biglen;
8f203108 925#ifdef MSCRYPTOAPI
fb09bf1c 926 /* Allocate enough buffer space for extra block
8f203108 927 * for MS CryptEncrypt() */
32874aea 928 pktout.data = (pktout.data == NULL ? smalloc(biglen + 12) :
929 srealloc(pktout.data, biglen + 12));
8f203108 930#else
32874aea 931 pktout.data = (pktout.data == NULL ? smalloc(biglen + 4) :
932 srealloc(pktout.data, biglen + 4));
8f203108 933#endif
374330e2 934 if (!pktout.data)
935 fatalbox("Out of memory");
936 }
32874aea 937 pktout.body = pktout.data + 4 + pad + 1;
4ba9b64b 938}
374330e2 939
32874aea 940static void s_wrpkt_start(int type, int len)
941{
4ba9b64b 942 ssh1_pktout_size(len);
374330e2 943 pktout.type = type;
374330e2 944}
945
32874aea 946static int s_wrpkt_prepare(void)
947{
374330e2 948 int pad, len, biglen, i;
949 unsigned long crc;
950
4ba9b64b 951 pktout.body[-1] = pktout.type;
952
765c4200 953#ifdef DUMP_PACKETS
7d503c31 954 debug(("Packet payload pre-compression:\n"));
32874aea 955 dmemdump(pktout.body - 1, pktout.length + 1);
7d503c31 956#endif
957
4ba9b64b 958 if (ssh1_compressing) {
959 unsigned char *compblk;
960 int complen;
32874aea 961 zlib_compress_block(pktout.body - 1, pktout.length + 1,
4ba9b64b 962 &compblk, &complen);
32874aea 963 ssh1_pktout_size(complen - 1);
964 memcpy(pktout.body - 1, compblk, complen);
dcbde236 965 sfree(compblk);
765c4200 966#ifdef DUMP_PACKETS
4ba9b64b 967 debug(("Packet payload post-compression:\n"));
32874aea 968 dmemdump(pktout.body - 1, pktout.length + 1);
4ba9b64b 969#endif
970 }
971
374330e2 972 len = pktout.length + 5; /* type and CRC */
32874aea 973 pad = 8 - (len % 8);
374330e2 974 biglen = len + pad;
975
32874aea 976 for (i = 0; i < pad; i++)
977 pktout.data[i + 4] = random_byte();
978 crc = crc32(pktout.data + 4, biglen - 4);
979 PUT_32BIT(pktout.data + biglen, crc);
fb09bf1c 980 PUT_32BIT(pktout.data, len);
374330e2 981
765c4200 982#ifdef DUMP_PACKETS
32874aea 983 debug(("Sending packet len=%d\n", biglen + 4));
984 dmemdump(pktout.data, biglen + 4);
698a5108 985#endif
374330e2 986 if (cipher)
32874aea 987 cipher->encrypt(pktout.data + 4, biglen);
374330e2 988
32874aea 989 return biglen + 4;
39065bed 990}
991
32874aea 992static void s_wrpkt(void)
993{
5471d09a 994 int len, backlog;
39065bed 995 len = s_wrpkt_prepare();
5471d09a 996 backlog = sk_write(s, pktout.data, len);
997 if (backlog > SSH_MAX_BACKLOG)
998 ssh_throttle_all(1, backlog);
39065bed 999}
1000
32874aea 1001static void s_wrpkt_defer(void)
1002{
39065bed 1003 int len;
1004 len = s_wrpkt_prepare();
1005 if (deferred_len + len > deferred_size) {
32874aea 1006 deferred_size = deferred_len + len + 128;
1007 deferred_send_data = srealloc(deferred_send_data, deferred_size);
39065bed 1008 }
32874aea 1009 memcpy(deferred_send_data + deferred_len, pktout.data, len);
39065bed 1010 deferred_len += len;
374330e2 1011}
1012
fb09bf1c 1013/*
39065bed 1014 * Construct a packet with the specified contents.
fb09bf1c 1015 */
39065bed 1016static void construct_packet(int pkttype, va_list ap1, va_list ap2)
fb09bf1c 1017{
fb09bf1c 1018 unsigned char *p, *argp, argchar;
1019 unsigned long argint;
1020 int pktlen, argtype, arglen;
7cca0d81 1021 Bignum bn;
fb09bf1c 1022
1023 pktlen = 0;
39065bed 1024 while ((argtype = va_arg(ap1, int)) != PKT_END) {
fb09bf1c 1025 switch (argtype) {
1026 case PKT_INT:
39065bed 1027 (void) va_arg(ap1, int);
fb09bf1c 1028 pktlen += 4;
1029 break;
1030 case PKT_CHAR:
39065bed 1031 (void) va_arg(ap1, char);
fb09bf1c 1032 pktlen++;
1033 break;
1034 case PKT_DATA:
39065bed 1035 (void) va_arg(ap1, unsigned char *);
1036 arglen = va_arg(ap1, int);
fb09bf1c 1037 pktlen += arglen;
1038 break;
1039 case PKT_STR:
39065bed 1040 argp = va_arg(ap1, unsigned char *);
fb09bf1c 1041 arglen = strlen(argp);
1042 pktlen += 4 + arglen;
1043 break;
7cca0d81 1044 case PKT_BIGNUM:
39065bed 1045 bn = va_arg(ap1, Bignum);
32874aea 1046 pktlen += ssh1_bignum_length(bn);
7cca0d81 1047 break;
fb09bf1c 1048 default:
1049 assert(0);
1050 }
1051 }
fb09bf1c 1052
1053 s_wrpkt_start(pkttype, pktlen);
1054 p = pktout.body;
1055
39065bed 1056 while ((argtype = va_arg(ap2, int)) != PKT_END) {
fb09bf1c 1057 switch (argtype) {
1058 case PKT_INT:
39065bed 1059 argint = va_arg(ap2, int);
fb09bf1c 1060 PUT_32BIT(p, argint);
1061 p += 4;
1062 break;
1063 case PKT_CHAR:
39065bed 1064 argchar = va_arg(ap2, unsigned char);
fb09bf1c 1065 *p = argchar;
1066 p++;
1067 break;
1068 case PKT_DATA:
39065bed 1069 argp = va_arg(ap2, unsigned char *);
1070 arglen = va_arg(ap2, int);
fb09bf1c 1071 memcpy(p, argp, arglen);
1072 p += arglen;
1073 break;
1074 case PKT_STR:
39065bed 1075 argp = va_arg(ap2, unsigned char *);
fb09bf1c 1076 arglen = strlen(argp);
1077 PUT_32BIT(p, arglen);
1078 memcpy(p + 4, argp, arglen);
1079 p += 4 + arglen;
1080 break;
7cca0d81 1081 case PKT_BIGNUM:
39065bed 1082 bn = va_arg(ap2, Bignum);
32874aea 1083 p += ssh1_write_bignum(p, bn);
7cca0d81 1084 break;
fb09bf1c 1085 }
1086 }
39065bed 1087}
fb09bf1c 1088
32874aea 1089static void send_packet(int pkttype, ...)
1090{
39065bed 1091 va_list ap1, ap2;
1092 va_start(ap1, pkttype);
1093 va_start(ap2, pkttype);
1094 construct_packet(pkttype, ap1, ap2);
fb09bf1c 1095 s_wrpkt();
1096}
1097
32874aea 1098static void defer_packet(int pkttype, ...)
1099{
39065bed 1100 va_list ap1, ap2;
1101 va_start(ap1, pkttype);
1102 va_start(ap2, pkttype);
1103 construct_packet(pkttype, ap1, ap2);
1104 s_wrpkt_defer();
1105}
1106
32874aea 1107static int ssh_versioncmp(char *a, char *b)
1108{
9697bfd2 1109 char *ae, *be;
1110 unsigned long av, bv;
1111
43aa02a7 1112 av = strtoul(a, &ae, 10);
1113 bv = strtoul(b, &be, 10);
32874aea 1114 if (av != bv)
1115 return (av < bv ? -1 : +1);
1116 if (*ae == '.')
1117 ae++;
1118 if (*be == '.')
1119 be++;
43aa02a7 1120 av = strtoul(ae, &ae, 10);
1121 bv = strtoul(be, &be, 10);
32874aea 1122 if (av != bv)
1123 return (av < bv ? -1 : +1);
9697bfd2 1124 return 0;
1125}
1126
e5574168 1127
1128/*
a92dd380 1129 * Utility routines for putting an SSH-protocol `string' and
1130 * `uint32' into a SHA state.
e5574168 1131 */
1132#include <stdio.h>
32874aea 1133static void sha_string(SHA_State * s, void *str, int len)
1134{
e5574168 1135 unsigned char lenblk[4];
e5574168 1136 PUT_32BIT(lenblk, len);
e5574168 1137 SHA_Bytes(s, lenblk, 4);
e5574168 1138 SHA_Bytes(s, str, len);
1139}
1140
32874aea 1141static void sha_uint32(SHA_State * s, unsigned i)
1142{
a92dd380 1143 unsigned char intblk[4];
1144 PUT_32BIT(intblk, i);
1145 SHA_Bytes(s, intblk, 4);
1146}
1147
7cca0d81 1148/*
1149 * SSH2 packet construction functions.
1150 */
32874aea 1151static void ssh2_pkt_ensure(int length)
1152{
783415f8 1153 if (pktout.maxlen < length) {
32874aea 1154 pktout.maxlen = length + 256;
1155 pktout.data =
1156 (pktout.data ==
1157 NULL ? smalloc(pktout.maxlen +
1158 APIEXTRA) : srealloc(pktout.data,
1159 pktout.maxlen +
1160 APIEXTRA));
1161 if (!pktout.data)
1162 fatalbox("Out of memory");
7cca0d81 1163 }
783415f8 1164}
32874aea 1165static void ssh2_pkt_adddata(void *data, int len)
1166{
783415f8 1167 pktout.length += len;
1168 ssh2_pkt_ensure(pktout.length);
32874aea 1169 memcpy(pktout.data + pktout.length - len, data, len);
7cca0d81 1170}
32874aea 1171static void ssh2_pkt_addbyte(unsigned char byte)
1172{
7cca0d81 1173 ssh2_pkt_adddata(&byte, 1);
1174}
32874aea 1175static void ssh2_pkt_init(int pkt_type)
1176{
7cca0d81 1177 pktout.length = 5;
32874aea 1178 ssh2_pkt_addbyte((unsigned char) pkt_type);
7cca0d81 1179}
32874aea 1180static void ssh2_pkt_addbool(unsigned char value)
1181{
7cca0d81 1182 ssh2_pkt_adddata(&value, 1);
1183}
32874aea 1184static void ssh2_pkt_adduint32(unsigned long value)
1185{
7cca0d81 1186 unsigned char x[4];
1187 PUT_32BIT(x, value);
1188 ssh2_pkt_adddata(x, 4);
1189}
32874aea 1190static void ssh2_pkt_addstring_start(void)
1191{
7cca0d81 1192 ssh2_pkt_adduint32(0);
1193 pktout.savedpos = pktout.length;
1194}
32874aea 1195static void ssh2_pkt_addstring_str(char *data)
1196{
7cca0d81 1197 ssh2_pkt_adddata(data, strlen(data));
1198 PUT_32BIT(pktout.data + pktout.savedpos - 4,
32874aea 1199 pktout.length - pktout.savedpos);
7cca0d81 1200}
32874aea 1201static void ssh2_pkt_addstring_data(char *data, int len)
1202{
7cca0d81 1203 ssh2_pkt_adddata(data, len);
1204 PUT_32BIT(pktout.data + pktout.savedpos - 4,
32874aea 1205 pktout.length - pktout.savedpos);
7cca0d81 1206}
32874aea 1207static void ssh2_pkt_addstring(char *data)
1208{
7cca0d81 1209 ssh2_pkt_addstring_start();
1210 ssh2_pkt_addstring_str(data);
1211}
32874aea 1212static char *ssh2_mpint_fmt(Bignum b, int *len)
1213{
7cca0d81 1214 unsigned char *p;
32874aea 1215 int i, n = (bignum_bitcount(b) + 7) / 8;
3709bfe9 1216 p = smalloc(n + 1);
7cca0d81 1217 if (!p)
32874aea 1218 fatalbox("out of memory");
7cca0d81 1219 p[0] = 0;
3709bfe9 1220 for (i = 1; i <= n; i++)
32874aea 1221 p[i] = bignum_byte(b, n - i);
7cca0d81 1222 i = 0;
32874aea 1223 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1224 i++;
1225 memmove(p, p + i, n + 1 - i);
1226 *len = n + 1 - i;
7cca0d81 1227 return p;
1228}
32874aea 1229static void ssh2_pkt_addmp(Bignum b)
1230{
7cca0d81 1231 unsigned char *p;
1232 int len;
1233 p = ssh2_mpint_fmt(b, &len);
1234 ssh2_pkt_addstring_start();
1235 ssh2_pkt_addstring_data(p, len);
dcbde236 1236 sfree(p);
7cca0d81 1237}
b185170a 1238
1239/*
1240 * Construct an SSH2 final-form packet: compress it, encrypt it,
1241 * put the MAC on it. Final packet, ready to be sent, is stored in
1242 * pktout.data. Total length is returned.
1243 */
32874aea 1244static int ssh2_pkt_construct(void)
1245{
7cca0d81 1246 int cipherblk, maclen, padding, i;
1247 static unsigned long outgoing_sequence = 0;
1248
1249 /*
4ba9b64b 1250 * Compress packet payload.
1251 */
765c4200 1252#ifdef DUMP_PACKETS
1253 debug(("Pre-compression payload:\n"));
32874aea 1254 dmemdump(pktout.data + 5, pktout.length - 5);
4ba9b64b 1255#endif
1256 {
1257 unsigned char *newpayload;
1258 int newlen;
32874aea 1259 if (cscomp && cscomp->compress(pktout.data + 5, pktout.length - 5,
4ba9b64b 1260 &newpayload, &newlen)) {
1261 pktout.length = 5;
1262 ssh2_pkt_adddata(newpayload, newlen);
dcbde236 1263 sfree(newpayload);
4ba9b64b 1264 }
1265 }
1266
1267 /*
7cca0d81 1268 * Add padding. At least four bytes, and must also bring total
1269 * length (minus MAC) up to a multiple of the block size.
1270 */
32874aea 1271 cipherblk = cscipher ? cscipher->blksize : 8; /* block size */
1272 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
7cca0d81 1273 padding = 4;
32874aea 1274 padding +=
1275 (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
783415f8 1276 maclen = csmac ? csmac->len : 0;
1277 ssh2_pkt_ensure(pktout.length + padding + maclen);
7cca0d81 1278 pktout.data[4] = padding;
1279 for (i = 0; i < padding; i++)
32874aea 1280 pktout.data[pktout.length + i] = random_byte();
7cca0d81 1281 PUT_32BIT(pktout.data, pktout.length + padding - 4);
1282 if (csmac)
32874aea 1283 csmac->generate(pktout.data, pktout.length + padding,
1284 outgoing_sequence);
1285 outgoing_sequence++; /* whether or not we MACed */
7cca0d81 1286
765c4200 1287#ifdef DUMP_PACKETS
32874aea 1288 debug(("Sending packet len=%d\n", pktout.length + padding));
1289 dmemdump(pktout.data, pktout.length + padding);
7cca0d81 1290#endif
1291
1292 if (cscipher)
32874aea 1293 cscipher->encrypt(pktout.data, pktout.length + padding);
7cca0d81 1294
b185170a 1295 /* Ready-to-send packet starts at pktout.data. We return length. */
1296 return pktout.length + padding + maclen;
1297}
1298
1299/*
1300 * Construct and send an SSH2 packet immediately.
1301 */
32874aea 1302static void ssh2_pkt_send(void)
1303{
5471d09a 1304 int len;
1305 int backlog;
1306 len = ssh2_pkt_construct();
1307 backlog = sk_write(s, pktout.data, len);
1308 if (backlog > SSH_MAX_BACKLOG)
1309 ssh_throttle_all(1, backlog);
b185170a 1310}
1311
1312/*
1313 * Construct an SSH2 packet and add it to a deferred data block.
1314 * Useful for sending multiple packets in a single sk_write() call,
1315 * to prevent a traffic-analysing listener from being able to work
1316 * out the length of any particular packet (such as the password
1317 * packet).
1318 *
1319 * Note that because SSH2 sequence-numbers its packets, this can
1320 * NOT be used as an m4-style `defer' allowing packets to be
1321 * constructed in one order and sent in another.
1322 */
32874aea 1323static void ssh2_pkt_defer(void)
1324{
b185170a 1325 int len = ssh2_pkt_construct();
1326 if (deferred_len + len > deferred_size) {
32874aea 1327 deferred_size = deferred_len + len + 128;
1328 deferred_send_data = srealloc(deferred_send_data, deferred_size);
b185170a 1329 }
32874aea 1330 memcpy(deferred_send_data + deferred_len, pktout.data, len);
b185170a 1331 deferred_len += len;
1332}
1333
1334/*
1335 * Send the whole deferred data block constructed by
39065bed 1336 * ssh2_pkt_defer() or SSH1's defer_packet().
b185170a 1337 */
32874aea 1338static void ssh_pkt_defersend(void)
1339{
5471d09a 1340 int backlog;
1341 backlog = sk_write(s, deferred_send_data, deferred_len);
b185170a 1342 deferred_len = deferred_size = 0;
1343 sfree(deferred_send_data);
1344 deferred_send_data = NULL;
5471d09a 1345 if (backlog > SSH_MAX_BACKLOG)
1346 ssh_throttle_all(1, backlog);
7cca0d81 1347}
1348
1349#if 0
32874aea 1350void bndebug(char *string, Bignum b)
1351{
7cca0d81 1352 unsigned char *p;
1353 int i, len;
1354 p = ssh2_mpint_fmt(b, &len);
1355 debug(("%s", string));
1356 for (i = 0; i < len; i++)
32874aea 1357 debug((" %02x", p[i]));
765c4200 1358 debug(("\n"));
dcbde236 1359 sfree(p);
7cca0d81 1360}
1361#endif
1362
32874aea 1363static void sha_mpint(SHA_State * s, Bignum b)
1364{
7cca0d81 1365 unsigned char *p;
1366 int len;
1367 p = ssh2_mpint_fmt(b, &len);
1368 sha_string(s, p, len);
dcbde236 1369 sfree(p);
7cca0d81 1370}
1371
1372/*
1373 * SSH2 packet decode functions.
1374 */
32874aea 1375static unsigned long ssh2_pkt_getuint32(void)
1376{
7cca0d81 1377 unsigned long value;
1378 if (pktin.length - pktin.savedpos < 4)
32874aea 1379 return 0; /* arrgh, no way to decline (FIXME?) */
1380 value = GET_32BIT(pktin.data + pktin.savedpos);
7cca0d81 1381 pktin.savedpos += 4;
1382 return value;
1383}
32874aea 1384static int ssh2_pkt_getbool(void)
1385{
65a22376 1386 unsigned long value;
1387 if (pktin.length - pktin.savedpos < 1)
32874aea 1388 return 0; /* arrgh, no way to decline (FIXME?) */
65a22376 1389 value = pktin.data[pktin.savedpos] != 0;
1390 pktin.savedpos++;
1391 return value;
1392}
32874aea 1393static void ssh2_pkt_getstring(char **p, int *length)
1394{
7cca0d81 1395 *p = NULL;
1396 if (pktin.length - pktin.savedpos < 4)
32874aea 1397 return;
1398 *length = GET_32BIT(pktin.data + pktin.savedpos);
7cca0d81 1399 pktin.savedpos += 4;
1400 if (pktin.length - pktin.savedpos < *length)
32874aea 1401 return;
1402 *p = pktin.data + pktin.savedpos;
7cca0d81 1403 pktin.savedpos += *length;
1404}
32874aea 1405static Bignum ssh2_pkt_getmp(void)
1406{
7cca0d81 1407 char *p;
3709bfe9 1408 int length;
7cca0d81 1409 Bignum b;
1410
1411 ssh2_pkt_getstring(&p, &length);
1412 if (!p)
32874aea 1413 return NULL;
8d5de777 1414 if (p[0] & 0x80) {
32874aea 1415 bombout(("internal error: Can't handle negative mpints"));
1416 return NULL;
8d5de777 1417 }
3709bfe9 1418 b = bignum_from_bytes(p, length);
7cca0d81 1419 return b;
1420}
1421
7d503c31 1422/*
1423 * Examine the remote side's version string and compare it against
1424 * a list of known buggy implementations.
1425 */
32874aea 1426static void ssh_detect_bugs(char *vstring)
1427{
1428 char *imp; /* pointer to implementation part */
7d503c31 1429 imp = vstring;
1430 imp += strcspn(imp, "-");
32874aea 1431 if (*imp)
1432 imp++;
7d503c31 1433 imp += strcspn(imp, "-");
32874aea 1434 if (*imp)
1435 imp++;
7d503c31 1436
1437 ssh_remote_bugs = 0;
1438
1439 if (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
32874aea 1440 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1441 !strcmp(imp, "1.2.22")) {
1442 /*
1443 * These versions don't support SSH1_MSG_IGNORE, so we have
1444 * to use a different defence against password length
1445 * sniffing.
1446 */
1447 ssh_remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1448 logevent("We believe remote version has SSH1 ignore bug");
7d503c31 1449 }
1450
1451 if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
32874aea 1452 !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
1453 !strncmp(imp, "2.1 ", 4)) {
1454 /*
1455 * These versions have the HMAC bug.
1456 */
1457 ssh_remote_bugs |= BUG_SSH2_HMAC;
1458 logevent("We believe remote version has SSH2 HMAC bug");
7d503c31 1459 }
1460}
1461
32874aea 1462static int do_ssh_init(unsigned char c)
1463{
2d466ffd 1464 static int vslen;
8df7a775 1465 static char version[10];
50526e47 1466 static char *vstring;
1467 static int vstrsize;
1468 static char *vlog;
8df7a775 1469 static int i;
374330e2 1470
8df7a775 1471 crBegin;
1472
1473 /* Search for the string "SSH-" in the input. */
374330e2 1474 i = 0;
8df7a775 1475 while (1) {
1476 static const int transS[] = { 1, 2, 2, 1 };
1477 static const int transH[] = { 0, 0, 3, 0 };
1478 static const int transminus[] = { 0, 0, 0, -1 };
32874aea 1479 if (c == 'S')
1480 i = transS[i];
1481 else if (c == 'H')
1482 i = transH[i];
1483 else if (c == '-')
1484 i = transminus[i];
1485 else
1486 i = 0;
8df7a775 1487 if (i < 0)
1488 break;
1489 crReturn(1); /* get another character */
374330e2 1490 }
8df7a775 1491
50526e47 1492 vstring = smalloc(16);
1493 vstrsize = 16;
c5e9c988 1494 strcpy(vstring, "SSH-");
50526e47 1495 vslen = 4;
374330e2 1496 i = 0;
1497 while (1) {
8df7a775 1498 crReturn(1); /* get another char */
32874aea 1499 if (vslen >= vstrsize - 1) {
1500 vstrsize += 16;
1501 vstring = srealloc(vstring, vstrsize);
1502 }
1503 vstring[vslen++] = c;
374330e2 1504 if (i >= 0) {
1505 if (c == '-') {
1506 version[i] = '\0';
1507 i = -1;
32874aea 1508 } else if (i < sizeof(version) - 1)
374330e2 1509 version[i++] = c;
32874aea 1510 } else if (c == '\n')
374330e2 1511 break;
1512 }
1513
db7d555c 1514 ssh_agentfwd_enabled = FALSE;
960e736a 1515 rdpkt2_state.incoming_sequence = 0;
1516
50526e47 1517 vstring[vslen] = 0;
9275ca8a 1518 vlog = smalloc(20 + vslen);
c5e9c988 1519 sprintf(vlog, "Server version: %s", vstring);
7d503c31 1520 ssh_detect_bugs(vstring);
c5e9c988 1521 vlog[strcspn(vlog, "\r\n")] = '\0';
1522 logevent(vlog);
9275ca8a 1523 sfree(vlog);
c5e9c988 1524
adf799dd 1525 /*
1526 * Server version "1.99" means we can choose whether we use v1
1527 * or v2 protocol. Choice is based on cfg.sshprot.
1528 */
1529 if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
32874aea 1530 /*
1531 * This is a v2 server. Begin v2 protocol.
1532 */
1533 char verstring[80], vlog[100];
1534 sprintf(verstring, "SSH-2.0-%s", sshver);
1535 SHA_Init(&exhashbase);
1536 /*
1537 * Hash our version string and their version string.
1538 */
1539 sha_string(&exhashbase, verstring, strlen(verstring));
1540 sha_string(&exhashbase, vstring, strcspn(vstring, "\r\n"));
1541 sprintf(vlog, "We claim version: %s", verstring);
1542 logevent(vlog);
1543 strcat(verstring, "\n");
1544 logevent("Using SSH protocol version 2");
1545 sk_write(s, verstring, strlen(verstring));
1546 ssh_protocol = ssh2_protocol;
1547 ssh_version = 2;
1548 s_rdpkt = ssh2_rdpkt;
e5574168 1549 } else {
32874aea 1550 /*
1551 * This is a v1 server. Begin v1 protocol.
1552 */
1553 char verstring[80], vlog[100];
1554 sprintf(verstring, "SSH-%s-%s",
1555 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"),
1556 sshver);
1557 sprintf(vlog, "We claim version: %s", verstring);
1558 logevent(vlog);
1559 strcat(verstring, "\n");
1560 logevent("Using SSH protocol version 1");
1561 sk_write(s, verstring, strlen(verstring));
1562 ssh_protocol = ssh1_protocol;
1563 ssh_version = 1;
1564 s_rdpkt = ssh1_rdpkt;
e5574168 1565 }
3687d221 1566 ssh_state = SSH_STATE_BEFORE_SIZE;
8df7a775 1567
50526e47 1568 sfree(vstring);
50526e47 1569
8df7a775 1570 crFinish(0);
1571}
1572
1573static void ssh_gotdata(unsigned char *data, int datalen)
1574{
1575 crBegin;
1576
1577 /*
1578 * To begin with, feed the characters one by one to the
1579 * protocol initialisation / selection function do_ssh_init().
1580 * When that returns 0, we're done with the initial greeting
1581 * exchange and can move on to packet discipline.
1582 */
1583 while (1) {
1584 int ret;
1585 if (datalen == 0)
1586 crReturnV; /* more data please */
1587 ret = do_ssh_init(*data);
32874aea 1588 data++;
1589 datalen--;
8df7a775 1590 if (ret == 0)
1591 break;
1592 }
1593
1594 /*
1595 * We emerge from that loop when the initial negotiation is
1596 * over and we have selected an s_rdpkt function. Now pass
1597 * everything to s_rdpkt, and then pass the resulting packets
1598 * to the proper protocol handler.
1599 */
1600 if (datalen == 0)
1601 crReturnV;
1602 while (1) {
1603 while (datalen > 0) {
32874aea 1604 if (s_rdpkt(&data, &datalen) == 0) {
e14d0f19 1605 if (ssh_state == SSH_STATE_CLOSED) {
1606 return;
1607 }
8df7a775 1608 ssh_protocol(NULL, 0, 1);
1609 if (ssh_state == SSH_STATE_CLOSED) {
1610 return;
1611 }
1612 }
1613 }
1614 crReturnV;
1615 }
1616 crFinishV;
1617}
1618
32874aea 1619static int ssh_closing(Plug plug, char *error_msg, int error_code,
1620 int calling_back)
1621{
7e78000d 1622 ssh_state = SSH_STATE_CLOSED;
f3ab576e 1623 if (s) {
1624 sk_close(s);
1625 s = NULL;
1626 }
7e78000d 1627 if (error_msg) {
32874aea 1628 /* A socket error has occurred. */
1629 connection_fatal(error_msg);
7e78000d 1630 } else {
1631 /* Otherwise, the remote side closed the connection normally. */
8df7a775 1632 }
7e78000d 1633 return 0;
1634}
1635
32874aea 1636static int ssh_receive(Plug plug, int urgent, char *data, int len)
1637{
1638 ssh_gotdata(data, len);
3257deae 1639 if (ssh_state == SSH_STATE_CLOSED) {
32874aea 1640 if (s) {
1641 sk_close(s);
1642 s = NULL;
1643 }
1644 return 0;
3257deae 1645 }
fef97f43 1646 return 1;
374330e2 1647}
1648
5471d09a 1649static void ssh_sent(Plug plug, int bufsize)
1650{
1651 /*
1652 * If the send backlog on the SSH socket itself clears, we
1653 * should unthrottle the whole world if it was throttled.
1654 */
1655 if (bufsize < SSH_MAX_BACKLOG)
1656 ssh_throttle_all(0, bufsize);
1657}
1658
fb09bf1c 1659/*
8df7a775 1660 * Connect to specified host and port.
1661 * Returns an error message, or NULL on success.
6e1ebb76 1662 * Also places the canonical host name into `realhost'. It must be
1663 * freed by the caller.
8df7a775 1664 */
1665static char *connect_to_host(char *host, int port, char **realhost)
1666{
7e78000d 1667 static struct plug_function_table fn_table = {
1668 ssh_closing,
5471d09a 1669 ssh_receive,
1670 ssh_sent,
1671 NULL
7e78000d 1672 }, *fn_table_ptr = &fn_table;
1673
8df7a775 1674 SockAddr addr;
1675 char *err;
1676#ifdef FWHACK
1677 char *FWhost;
1678 int FWport;
1679#endif
1680
32874aea 1681 savedhost = smalloc(1 + strlen(host));
8df7a775 1682 if (!savedhost)
1683 fatalbox("Out of memory");
1684 strcpy(savedhost, host);
1685
1686 if (port < 0)
1687 port = 22; /* default ssh port */
1688 savedport = port;
1689
1690#ifdef FWHACK
1691 FWhost = host;
1692 FWport = port;
1693 host = FWSTR;
1694 port = 23;
1695#endif
1696
1697 /*
1698 * Try to find host.
1699 */
3ad9d396 1700 {
1701 char buf[200];
1702 sprintf(buf, "Looking up host \"%.170s\"", host);
1703 logevent(buf);
1704 }
8df7a775 1705 addr = sk_namelookup(host, realhost);
32874aea 1706 if ((err = sk_addr_error(addr)))
8df7a775 1707 return err;
1708
1709#ifdef FWHACK
6e1ebb76 1710 *realhost = strdup(FWhost);
8df7a775 1711#endif
1712
1713 /*
1714 * Open socket.
1715 */
3ad9d396 1716 {
1717 char buf[200], addrbuf[100];
1718 sk_getaddr(addr, addrbuf, 100);
1719 sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
1720 logevent(buf);
1721 }
7e78000d 1722 s = sk_new(addr, port, 0, 1, &fn_table_ptr);
32874aea 1723 if ((err = sk_socket_error(s)))
8df7a775 1724 return err;
1725
1726#ifdef FWHACK
1727 sk_write(s, "connect ", 8);
1728 sk_write(s, FWhost, strlen(FWhost));
1729 {
1730 char buf[20];
1731 sprintf(buf, " %d\n", FWport);
1732 sk_write(s, buf, strlen(buf));
1733 }
1734#endif
1735
1736 return NULL;
1737}
1738
1739/*
5471d09a 1740 * Throttle or unthrottle the SSH connection.
1741 */
1742static void ssh1_throttle(int adjust)
1743{
1744 int old_count = ssh1_throttle_count;
1745 ssh1_throttle_count += adjust;
1746 assert(ssh1_throttle_count >= 0);
1747 if (ssh1_throttle_count && !old_count) {
1748 sk_set_frozen(s, 1);
1749 } else if (!ssh1_throttle_count && old_count) {
1750 sk_set_frozen(s, 0);
1751 }
1752}
1753
1754/*
1755 * Throttle or unthrottle _all_ local data streams (for when sends
1756 * on the SSH connection itself back up).
1757 */
1758static void ssh_throttle_all(int enable, int bufsize)
1759{
1760 int i;
1761 struct ssh_channel *c;
1762
1763 if (enable == ssh_throttled_all)
1764 return;
1765 ssh_throttled_all = enable;
1766 ssh_overall_bufsize = bufsize;
1767 if (!ssh_channels)
1768 return;
1769 for (i = 0; NULL != (c = index234(ssh_channels, i)); i++) {
1770 switch (c->type) {
1771 case CHAN_MAINSESSION:
1772 /*
1773 * This is treated separately, outside the switch.
1774 */
1775 break;
1776 case CHAN_X11:
1777 x11_override_throttle(c->u.x11.s, enable);
1778 break;
1779 case CHAN_AGENT:
1780 /* Agent channels require no buffer management. */
1781 break;
1782 case CHAN_SOCKDATA:
1783 pfd_override_throttle(c->u.x11.s, enable);
1784 break;
1785 }
1786 }
1787}
1788
1789/*
fb09bf1c 1790 * Handle the key exchange and user authentication phases.
1791 */
e5574168 1792static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
fb09bf1c 1793{
2d466ffd 1794 int i, j;
1795 static int len;
1796 static unsigned char *rsabuf, *keystr1, *keystr2;
374330e2 1797 unsigned char cookie[8];
1798 struct RSAKey servkey, hostkey;
1799 struct MD5Context md5c;
ccbfb941 1800 static unsigned long supported_ciphers_mask, supported_auths_mask;
7cca0d81 1801 static int tried_publickey;
614a20a0 1802 static int tis_auth_refused, ccard_auth_refused;
7cca0d81 1803 static unsigned char session_id[16];
2d466ffd 1804 static int cipher_type;
b585ec46 1805 static char username[100];
374330e2 1806
374330e2 1807 crBegin;
1808
32874aea 1809 if (!ispkt)
1810 crWaitUntil(ispkt);
374330e2 1811
8d5de777 1812 if (pktin.type != SSH1_SMSG_PUBLIC_KEY) {
1813 bombout(("Public key packet not received"));
32874aea 1814 crReturn(0);
8d5de777 1815 }
374330e2 1816
c5e9c988 1817 logevent("Received public keys");
374330e2 1818
c5e9c988 1819 memcpy(cookie, pktin.body, 8);
374330e2 1820
32874aea 1821 i = makekey(pktin.body + 8, &servkey, &keystr1, 0);
1822 j = makekey(pktin.body + 8 + i, &hostkey, &keystr2, 0);
374330e2 1823
c5e9c988 1824 /*
1c2a93c4 1825 * Log the host key fingerprint.
c5e9c988 1826 */
c5e9c988 1827 {
1828 char logmsg[80];
1c2a93c4 1829 logevent("Host key fingerprint is:");
c5e9c988 1830 strcpy(logmsg, " ");
32874aea 1831 hostkey.comment = NULL;
1832 rsa_fingerprint(logmsg + strlen(logmsg),
1833 sizeof(logmsg) - strlen(logmsg), &hostkey);
c5e9c988 1834 logevent(logmsg);
1835 }
1836
32874aea 1837 ssh1_remote_protoflags = GET_32BIT(pktin.body + 8 + i + j);
1838 supported_ciphers_mask = GET_32BIT(pktin.body + 12 + i + j);
1839 supported_auths_mask = GET_32BIT(pktin.body + 16 + i + j);
bea1ef5f 1840
32874aea 1841 ssh1_local_protoflags =
1842 ssh1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
b96dc54c 1843 ssh1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
1844
c5e9c988 1845 MD5Init(&md5c);
374330e2 1846 MD5Update(&md5c, keystr2, hostkey.bytes);
1847 MD5Update(&md5c, keystr1, servkey.bytes);
1848 MD5Update(&md5c, pktin.body, 8);
374330e2 1849 MD5Final(session_id, &md5c);
1850
32874aea 1851 for (i = 0; i < 32; i++)
374330e2 1852 session_key[i] = random_byte();
1853
1854 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
1855
dcbde236 1856 rsabuf = smalloc(len);
374330e2 1857 if (!rsabuf)
1858 fatalbox("Out of memory");
1859
89ee5268 1860 /*
1861 * Verify the host key.
1862 */
1863 {
32874aea 1864 /*
1865 * First format the key into a string.
1866 */
1867 int len = rsastr_len(&hostkey);
1868 char fingerprint[100];
1869 char *keystr = smalloc(len);
1870 if (!keystr)
1871 fatalbox("Out of memory");
1872 rsastr_fmt(keystr, &hostkey);
1873 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
1874 verify_ssh_host_key(savedhost, savedport, "rsa", keystr,
1875 fingerprint);
1876 sfree(keystr);
1877 }
1878
1879 for (i = 0; i < 32; i++) {
374330e2 1880 rsabuf[i] = session_key[i];
1881 if (i < 16)
1882 rsabuf[i] ^= session_id[i];
1883 }
1884
1885 if (hostkey.bytes > servkey.bytes) {
1886 rsaencrypt(rsabuf, 32, &servkey);
1887 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
1888 } else {
1889 rsaencrypt(rsabuf, 32, &hostkey);
1890 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
1891 }
1892
c5e9c988 1893 logevent("Encrypted session key");
1894
ca20bfcf 1895 {
1896 int cipher_chosen = 0, warn = 0;
1897 char *cipher_string = NULL;
1898 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
1899 int next_cipher = cfg.ssh_cipherlist[i];
1900 if (next_cipher == CIPHER_WARN) {
1901 /* If/when we choose a cipher, warn about it */
1902 warn = 1;
1903 } else if (next_cipher == CIPHER_AES) {
1904 /* XXX Probably don't need to mention this. */
1905 logevent("AES not supported in SSH1, skipping");
1906 } else {
1907 switch (next_cipher) {
1908 case CIPHER_3DES: cipher_type = SSH_CIPHER_3DES;
1909 cipher_string = "3DES"; break;
1910 case CIPHER_BLOWFISH: cipher_type = SSH_CIPHER_BLOWFISH;
1911 cipher_string = "Blowfish"; break;
1912 case CIPHER_DES: cipher_type = SSH_CIPHER_DES;
1913 cipher_string = "single-DES"; break;
1914 }
1915 if (supported_ciphers_mask & (1 << cipher_type))
1916 cipher_chosen = 1;
1917 }
1918 }
1919 if (!cipher_chosen) {
1920 if ((supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
1921 bombout(("Server violates SSH 1 protocol by not "
1922 "supporting 3DES encryption"));
1923 else
1924 /* shouldn't happen */
1925 bombout(("No supported ciphers found"));
a99a05c0 1926 crReturn(0);
1927 }
ca20bfcf 1928
1929 /* Warn about chosen cipher if necessary. */
1930 if (warn)
1931 askcipher(cipher_string, 0);
bea1ef5f 1932 }
ca20bfcf 1933
c5e9c988 1934 switch (cipher_type) {
32874aea 1935 case SSH_CIPHER_3DES:
1936 logevent("Using 3DES encryption");
1937 break;
1938 case SSH_CIPHER_DES:
1939 logevent("Using single-DES encryption");
1940 break;
1941 case SSH_CIPHER_BLOWFISH:
1942 logevent("Using Blowfish encryption");
1943 break;
c5e9c988 1944 }
bea1ef5f 1945
e5574168 1946 send_packet(SSH1_CMSG_SESSION_KEY,
32874aea 1947 PKT_CHAR, cipher_type,
1948 PKT_DATA, cookie, 8,
1949 PKT_CHAR, (len * 8) >> 8, PKT_CHAR, (len * 8) & 0xFF,
1950 PKT_DATA, rsabuf, len,
1951 PKT_INT, ssh1_local_protoflags, PKT_END);
fb09bf1c 1952
c5e9c988 1953 logevent("Trying to enable encryption...");
374330e2 1954
dcbde236 1955 sfree(rsabuf);
374330e2 1956
5e8358ad 1957 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
32874aea 1958 cipher_type == SSH_CIPHER_DES ? &ssh_des : &ssh_3des;
374330e2 1959 cipher->sesskey(session_key);
1960
fb09bf1c 1961 crWaitUntil(ispkt);
374330e2 1962
8d5de777 1963 if (pktin.type != SSH1_SMSG_SUCCESS) {
1964 bombout(("Encryption not successfully enabled"));
32874aea 1965 crReturn(0);
8d5de777 1966 }
374330e2 1967
c5e9c988 1968 logevent("Successfully started encryption");
1969
374330e2 1970 fflush(stdout);
1971 {
374330e2 1972 static int pos = 0;
1973 static char c;
67779be7 1974 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
32874aea 1975 if (ssh_get_line) {
1976 if (!ssh_get_line("login as: ",
1977 username, sizeof(username), FALSE)) {
1978 /*
1979 * get_line failed to get a username.
1980 * Terminate.
1981 */
1982 logevent("No username provided. Abandoning session.");
1983 ssh_state = SSH_STATE_CLOSED;
1984 crReturn(1);
1985 }
1986 } else {
1987 c_write_str("login as: ");
1988 ssh_send_ok = 1;
1989 while (pos >= 0) {
1990 crWaitUntil(!ispkt);
1991 while (inlen--)
1992 switch (c = *in++) {
1993 case 10:
1994 case 13:
1995 username[pos] = 0;
1996 pos = -1;
1997 break;
1998 case 8:
1999 case 127:
2000 if (pos > 0) {
2001 c_write_str("\b \b");
2002 pos--;
2003 }
2004 break;
2005 case 21:
2006 case 27:
2007 while (pos > 0) {
2008 c_write_str("\b \b");
2009 pos--;
2010 }
2011 break;
2012 case 3:
2013 case 4:
2014 random_save_seed();
2015 exit(0);
2016 break;
2017 default:
2018 if (((c >= ' ' && c <= '~') ||
51b2fb65 2019 ((unsigned char) c >= 160))
2020 && pos < sizeof(username)-1) {
32874aea 2021 username[pos++] = c;
2022 c_write(&c, 1);
2023 }
2024 break;
2025 }
2026 }
2027 c_write_str("\r\n");
2028 username[strcspn(username, "\n\r")] = '\0';
2029 }
2030 } else {
374330e2 2031 strncpy(username, cfg.username, 99);
2032 username[99] = '\0';
374330e2 2033 }
fb09bf1c 2034
e5574168 2035 send_packet(SSH1_CMSG_USER, PKT_STR, username, PKT_END);
c5e9c988 2036 {
32874aea 2037 char userlog[22 + sizeof(username)];
c5e9c988 2038 sprintf(userlog, "Sent username \"%s\"", username);
2039 logevent(userlog);
32874aea 2040 if (flags & FLAG_INTERACTIVE &&
2041 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
3c8e959b 2042 strcat(userlog, "\r\n");
32874aea 2043 c_write_str(userlog);
3c8e959b 2044 }
c5e9c988 2045 }
374330e2 2046 }
2047
fb09bf1c 2048 crWaitUntil(ispkt);
374330e2 2049
7cca0d81 2050 tried_publickey = 0;
614a20a0 2051 tis_auth_refused = ccard_auth_refused = 0;
7cca0d81 2052
e5574168 2053 while (pktin.type == SSH1_SMSG_FAILURE) {
374330e2 2054 static char password[100];
a52f067e 2055 static char prompt[200];
374330e2 2056 static int pos;
2057 static char c;
32874aea 2058 static int pwpkt_type;
32874aea 2059 pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
614a20a0 2060
32874aea 2061 if (agent_exists()) {
2062 /*
2063 * Attempt RSA authentication using Pageant.
2064 */
2065 static unsigned char request[5], *response, *p;
2066 static int responselen;
2067 static int i, nkeys;
2068 static int authed = FALSE;
2069 void *r;
2070
2071 logevent("Pageant is running. Requesting keys.");
2072
2073 /* Request the keys held by the agent. */
2074 PUT_32BIT(request, 1);
2075 request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2076 agent_query(request, 5, &r, &responselen);
2077 response = (unsigned char *) r;
2078 if (response && responselen >= 5 &&
2079 response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2080 p = response + 5;
2081 nkeys = GET_32BIT(p);
2082 p += 4;
2083 {
2084 char buf[64];
2085 sprintf(buf, "Pageant has %d SSH1 keys", nkeys);
2086 logevent(buf);
2087 }
2088 for (i = 0; i < nkeys; i++) {
2089 static struct RSAKey key;
2090 static Bignum challenge;
2091 static char *commentp;
2092 static int commentlen;
2093
2094 {
2095 char buf[64];
2096 sprintf(buf, "Trying Pageant key #%d", i);
2097 logevent(buf);
2098 }
2099 p += 4;
2100 p += ssh1_read_bignum(p, &key.exponent);
2101 p += ssh1_read_bignum(p, &key.modulus);
2102 commentlen = GET_32BIT(p);
2103 p += 4;
2104 commentp = p;
2105 p += commentlen;
2106 send_packet(SSH1_CMSG_AUTH_RSA,
2107 PKT_BIGNUM, key.modulus, PKT_END);
2108 crWaitUntil(ispkt);
2109 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2110 logevent("Key refused");
2111 continue;
2112 }
2113 logevent("Received RSA challenge");
2114 ssh1_read_bignum(pktin.body, &challenge);
2115 {
2116 char *agentreq, *q, *ret;
2d466ffd 2117 void *vret;
32874aea 2118 int len, retlen;
2119 len = 1 + 4; /* message type, bit count */
2120 len += ssh1_bignum_length(key.exponent);
2121 len += ssh1_bignum_length(key.modulus);
2122 len += ssh1_bignum_length(challenge);
2123 len += 16; /* session id */
2124 len += 4; /* response format */
2125 agentreq = smalloc(4 + len);
2126 PUT_32BIT(agentreq, len);
2127 q = agentreq + 4;
2128 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2129 PUT_32BIT(q, bignum_bitcount(key.modulus));
2130 q += 4;
2131 q += ssh1_write_bignum(q, key.exponent);
2132 q += ssh1_write_bignum(q, key.modulus);
2133 q += ssh1_write_bignum(q, challenge);
2134 memcpy(q, session_id, 16);
2135 q += 16;
2136 PUT_32BIT(q, 1); /* response format */
2d466ffd 2137 agent_query(agentreq, len + 4, &vret, &retlen);
2138 ret = vret;
32874aea 2139 sfree(agentreq);
2140 if (ret) {
2141 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2142 logevent("Sending Pageant's response");
2143 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
2144 PKT_DATA, ret + 5, 16,
2145 PKT_END);
2146 sfree(ret);
2147 crWaitUntil(ispkt);
2148 if (pktin.type == SSH1_SMSG_SUCCESS) {
2149 logevent
2150 ("Pageant's response accepted");
2151 if (flags & FLAG_VERBOSE) {
2152 c_write_str
2153 ("Authenticated using RSA key \"");
2154 c_write(commentp, commentlen);
2155 c_write_str("\" from agent\r\n");
2156 }
2157 authed = TRUE;
2158 } else
2159 logevent
2160 ("Pageant's response not accepted");
2161 } else {
2162 logevent
2163 ("Pageant failed to answer challenge");
2164 sfree(ret);
2165 }
2166 } else {
2167 logevent("No reply received from Pageant");
2168 }
2169 }
2170 freebn(key.exponent);
2171 freebn(key.modulus);
2172 freebn(challenge);
2173 if (authed)
2174 break;
2175 }
2176 }
2177 if (authed)
2178 break;
2179 }
2180 if (*cfg.keyfile && !tried_publickey)
2181 pwpkt_type = SSH1_CMSG_AUTH_RSA;
2182
614a20a0 2183 if (cfg.try_tis_auth &&
2184 (supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2185 !tis_auth_refused) {
32874aea 2186 pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2187 logevent("Requested TIS authentication");
2188 send_packet(SSH1_CMSG_AUTH_TIS, PKT_END);
2189 crWaitUntil(ispkt);
2190 if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2191 logevent("TIS authentication declined");
2192 if (flags & FLAG_INTERACTIVE)
2193 c_write_str("TIS authentication refused.\r\n");
614a20a0 2194 tis_auth_refused = 1;
2195 continue;
32874aea 2196 } else {
2197 int challengelen = ((pktin.body[0] << 24) |
2198 (pktin.body[1] << 16) |
2199 (pktin.body[2] << 8) |
2200 (pktin.body[3]));
2201 logevent("Received TIS challenge");
2202 if (challengelen > sizeof(prompt) - 1)
2203 challengelen = sizeof(prompt) - 1; /* prevent overrun */
2204 memcpy(prompt, pktin.body + 4, challengelen);
614a20a0 2205 /* Prompt heuristic comes from OpenSSH */
2206 strncpy(prompt + challengelen,
2207 memchr(prompt, '\n', challengelen) ?
2208 "": "\r\nResponse: ",
2209 (sizeof prompt) - challengelen);
2210 prompt[(sizeof prompt) - 1] = '\0';
32874aea 2211 }
2212 }
614a20a0 2213 if (cfg.try_tis_auth &&
2214 (supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2215 !ccard_auth_refused) {
32874aea 2216 pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2217 logevent("Requested CryptoCard authentication");
2218 send_packet(SSH1_CMSG_AUTH_CCARD, PKT_END);
2219 crWaitUntil(ispkt);
2220 if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2221 logevent("CryptoCard authentication declined");
2222 c_write_str("CryptoCard authentication refused.\r\n");
614a20a0 2223 ccard_auth_refused = 1;
2224 continue;
32874aea 2225 } else {
2226 int challengelen = ((pktin.body[0] << 24) |
2227 (pktin.body[1] << 16) |
2228 (pktin.body[2] << 8) |
2229 (pktin.body[3]));
2230 logevent("Received CryptoCard challenge");
2231 if (challengelen > sizeof(prompt) - 1)
2232 challengelen = sizeof(prompt) - 1; /* prevent overrun */
2233 memcpy(prompt, pktin.body + 4, challengelen);
614a20a0 2234 strncpy(prompt + challengelen,
2235 memchr(prompt, '\n', challengelen) ?
2236 "" : "\r\nResponse: ",
32874aea 2237 sizeof(prompt) - challengelen);
2238 prompt[sizeof(prompt) - 1] = '\0';
2239 }
2240 }
2241 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2242 sprintf(prompt, "%.90s@%.90s's password: ",
2243 username, savedhost);
2244 }
2245 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2246 char *comment = NULL;
2247 if (flags & FLAG_VERBOSE)
2248 c_write_str("Trying public key authentication.\r\n");
2249 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
2250 if (flags & FLAG_VERBOSE)
2251 c_write_str("No passphrase required.\r\n");
2252 goto tryauth;
2253 }
2254 sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
2255 sfree(comment);
2256 }
a52f067e 2257
614a20a0 2258 /*
2259 * Show password prompt, having first obtained it via a TIS
2260 * or CryptoCard exchange if we're doing TIS or CryptoCard
2261 * authentication.
2262 */
fa17a66e 2263 if (ssh_get_line) {
2264 if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) {
32874aea 2265 /*
2266 * get_line failed to get a password (for example
2267 * because one was supplied on the command line
2268 * which has already failed to work). Terminate.
2269 */
2bc6a386 2270 send_packet(SSH1_MSG_DISCONNECT,
2271 PKT_STR, "No more passwords available to try",
2272 PKT_END);
2273 connection_fatal("Unable to authenticate");
32874aea 2274 ssh_state = SSH_STATE_CLOSED;
2275 crReturn(1);
2276 }
fb09bf1c 2277 } else {
614a20a0 2278 /* Prompt may have come from server. We've munged it a bit, so
2279 * we know it to be zero-terminated at least once. */
2280 c_write_untrusted(prompt, strlen(prompt));
32874aea 2281 pos = 0;
2282 ssh_send_ok = 1;
2283 while (pos >= 0) {
2284 crWaitUntil(!ispkt);
2285 while (inlen--)
2286 switch (c = *in++) {
2287 case 10:
2288 case 13:
2289 password[pos] = 0;
2290 pos = -1;
2291 break;
2292 case 8:
2293 case 127:
2294 if (pos > 0)
2295 pos--;
2296 break;
2297 case 21:
2298 case 27:
2299 pos = 0;
2300 break;
2301 case 3:
2302 case 4:
2303 random_save_seed();
2304 exit(0);
2305 break;
2306 default:
51b2fb65 2307 if (pos < sizeof(password)-1)
32874aea 2308 password[pos++] = c;
2309 break;
2310 }
2311 }
2312 c_write_str("\r\n");
2313 }
2314
2315 tryauth:
7cca0d81 2316 if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
32874aea 2317 /*
2318 * Try public key authentication with the specified
2319 * key file.
2320 */
2321 static struct RSAKey pubkey;
2322 static Bignum challenge, response;
2323 static int i;
2324 static unsigned char buffer[32];
2325
2326 tried_publickey = 1;
2327 i = loadrsakey(cfg.keyfile, &pubkey, password);
2328 if (i == 0) {
7963af2f 2329 c_write_str("Couldn't load private key from ");
32874aea 2330 c_write_str(cfg.keyfile);
2331 c_write_str(".\r\n");
2332 continue; /* go and try password */
2333 }
2334 if (i == -1) {
2335 c_write_str("Wrong passphrase.\r\n");
2336 tried_publickey = 0;
2337 continue; /* try again */
2338 }
2339
2340 /*
2341 * Send a public key attempt.
2342 */
2343 send_packet(SSH1_CMSG_AUTH_RSA,
2344 PKT_BIGNUM, pubkey.modulus, PKT_END);
2345
2346 crWaitUntil(ispkt);
2347 if (pktin.type == SSH1_SMSG_FAILURE) {
2348 c_write_str("Server refused our public key.\r\n");
2349 continue; /* go and try password */
2350 }
2351 if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2352 bombout(("Bizarre response to offer of public key"));
2353 crReturn(0);
2354 }
2355 ssh1_read_bignum(pktin.body, &challenge);
2356 response = rsadecrypt(challenge, &pubkey);
2357 freebn(pubkey.private_exponent); /* burn the evidence */
2358
2359 for (i = 0; i < 32; i++) {
2360 buffer[i] = bignum_byte(response, 31 - i);
2361 }
2362
2363 MD5Init(&md5c);
2364 MD5Update(&md5c, buffer, 32);
2365 MD5Update(&md5c, session_id, 16);
2366 MD5Final(buffer, &md5c);
2367
2368 send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
2369 PKT_DATA, buffer, 16, PKT_END);
2370
2371 crWaitUntil(ispkt);
2372 if (pktin.type == SSH1_SMSG_FAILURE) {
2373 if (flags & FLAG_VERBOSE)
2374 c_write_str
2375 ("Failed to authenticate with our public key.\r\n");
2376 continue; /* go and try password */
2377 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
2378 bombout(
2379 ("Bizarre response to RSA authentication response"));
2380 crReturn(0);
2381 }
2382
2383 break; /* we're through! */
2384 } else {
2385 if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2386 /*
2387 * Defence against traffic analysis: we send a
2388 * whole bunch of packets containing strings of
2389 * different lengths. One of these strings is the
2390 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2391 * The others are all random data in
2392 * SSH1_MSG_IGNORE packets. This way a passive
2393 * listener can't tell which is the password, and
2394 * hence can't deduce the password length.
2395 *
2396 * Anybody with a password length greater than 16
2397 * bytes is going to have enough entropy in their
2398 * password that a listener won't find it _that_
2399 * much help to know how long it is. So what we'll
2400 * do is:
2401 *
2402 * - if password length < 16, we send 15 packets
2403 * containing string lengths 1 through 15
2404 *
2405 * - otherwise, we let N be the nearest multiple
2406 * of 8 below the password length, and send 8
2407 * packets containing string lengths N through
2408 * N+7. This won't obscure the order of
2409 * magnitude of the password length, but it will
2410 * introduce a bit of extra uncertainty.
2411 *
2412 * A few servers (the old 1.2.18 through 1.2.22)
2413 * can't deal with SSH1_MSG_IGNORE. For these
2414 * servers, we need an alternative defence. We make
2415 * use of the fact that the password is interpreted
2416 * as a C string: so we can append a NUL, then some
2417 * random data.
2418 */
2419 if (ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) {
2420 char string[64];
2421 char *s;
2422 int len;
2423
2424 len = strlen(password);
2425 if (len < sizeof(string)) {
2426 s = string;
2427 strcpy(string, password);
2428 len++; /* cover the zero byte */
2429 while (len < sizeof(string)) {
2430 string[len++] = (char) random_byte();
2431 }
2432 } else {
2433 s = password;
2434 }
2435 send_packet(pwpkt_type, PKT_INT, len,
2436 PKT_DATA, s, len, PKT_END);
2437 } else {
2438 int bottom, top, pwlen, i;
2439 char *randomstr;
2440
2441 pwlen = strlen(password);
2442 if (pwlen < 16) {
2443 bottom = 0; /* zero length passwords are OK! :-) */
2444 top = 15;
2445 } else {
2446 bottom = pwlen & ~7;
2447 top = bottom + 7;
2448 }
2449
2450 assert(pwlen >= bottom && pwlen <= top);
2451
2452 randomstr = smalloc(top + 1);
2453
2454 for (i = bottom; i <= top; i++) {
2455 if (i == pwlen)
2456 defer_packet(pwpkt_type, PKT_STR, password,
2457 PKT_END);
2458 else {
2459 for (j = 0; j < i; j++) {
2460 do {
2461 randomstr[j] = random_byte();
2462 } while (randomstr[j] == '\0');
2463 }
2464 randomstr[i] = '\0';
2465 defer_packet(SSH1_MSG_IGNORE,
2466 PKT_STR, randomstr, PKT_END);
2467 }
2468 }
2469 ssh_pkt_defersend();
2470 }
2471 } else {
2472 send_packet(pwpkt_type, PKT_STR, password, PKT_END);
2473 }
2474 }
c5e9c988 2475 logevent("Sent password");
374330e2 2476 memset(password, 0, strlen(password));
fb09bf1c 2477 crWaitUntil(ispkt);
e5574168 2478 if (pktin.type == SSH1_SMSG_FAILURE) {
32874aea 2479 if (flags & FLAG_VERBOSE)
2480 c_write_str("Access denied\r\n");
c5e9c988 2481 logevent("Authentication refused");
e5574168 2482 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
fb09bf1c 2483 logevent("Received disconnect request");
32874aea 2484 ssh_state = SSH_STATE_CLOSED;
85ee8208 2485 crReturn(1);
e5574168 2486 } else if (pktin.type != SSH1_SMSG_SUCCESS) {
8d5de777 2487 bombout(("Strange packet received, type %d", pktin.type));
32874aea 2488 crReturn(0);
374330e2 2489 }
2490 }
2491
c5e9c988 2492 logevent("Authentication successful");
2493
fb09bf1c 2494 crFinish(1);
2495}
2496
32874aea 2497void sshfwd_close(struct ssh_channel *c)
2498{
80e48603 2499 if (c && !c->closes) {
32874aea 2500 if (ssh_version == 1) {
2501 send_packet(SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2502 PKT_END);
2503 } else {
2504 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
2505 ssh2_pkt_adduint32(c->remoteid);
2506 ssh2_pkt_send();
2507 }
2508 c->closes = 1;
2509 if (c->type == CHAN_X11) {
2510 c->u.x11.s = NULL;
d74d141c 2511 logevent("Forwarded X11 connection terminated");
2512 } else if (c->type == CHAN_SOCKDATA) {
2513 c->u.pfd.s = NULL;
2514 logevent("Forwarded port closed");
32874aea 2515 }
2516 }
2517}
2518
5471d09a 2519int sshfwd_write(struct ssh_channel *c, char *buf, int len)
32874aea 2520{
783415f8 2521 if (ssh_version == 1) {
32874aea 2522 send_packet(SSH1_MSG_CHANNEL_DATA,
2523 PKT_INT, c->remoteid,
2524 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
5471d09a 2525 /*
2526 * In SSH1 we can return 0 here - implying that forwarded
2527 * connections are never individually throttled - because
2528 * the only circumstance that can cause throttling will be
2529 * the whole SSH connection backing up, in which case
2530 * _everything_ will be throttled as a whole.
2531 */
2532 return 0;
783415f8 2533 } else {
32874aea 2534 ssh2_add_channel_data(c, buf, len);
5471d09a 2535 return ssh2_try_send(c);
2536 }
2537}
2538
2539void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
2540{
2541 if (ssh_version == 1) {
2542 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
2543 c->v.v1.throttling = 0;
2544 ssh1_throttle(-1);
2545 }
2546 } else {
2547 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
783415f8 2548 }
9c964e85 2549}
2550
32874aea 2551static void ssh1_protocol(unsigned char *in, int inlen, int ispkt)
2552{
fb09bf1c 2553 crBegin;
2554
2555 random_init();
2556
e5574168 2557 while (!do_ssh1_login(in, inlen, ispkt)) {
fb09bf1c 2558 crReturnV;
85ee8208 2559 }
2560 if (ssh_state == SSH_STATE_CLOSED)
32874aea 2561 crReturnV;
fb09bf1c 2562
979310f1 2563 if (cfg.agentfwd && agent_exists()) {
32874aea 2564 logevent("Requesting agent forwarding");
2565 send_packet(SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
2566 do {
2567 crReturnV;
2568 } while (!ispkt);
2569 if (pktin.type != SSH1_SMSG_SUCCESS
2570 && pktin.type != SSH1_SMSG_FAILURE) {
2571 bombout(("Protocol confusion"));
2572 crReturnV;
2573 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2574 logevent("Agent forwarding refused");
2575 } else {
2576 logevent("Agent forwarding enabled");
db7d555c 2577 ssh_agentfwd_enabled = TRUE;
2578 }
dacbd0e8 2579 }
2580
9c964e85 2581 if (cfg.x11_forward) {
32874aea 2582 char proto[20], data[64];
2583 logevent("Requesting X11 forwarding");
2584 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
2585 if (ssh1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
2586 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2587 PKT_STR, proto, PKT_STR, data,
2588 PKT_INT, 0, PKT_END);
2589 } else {
2590 send_packet(SSH1_CMSG_X11_REQUEST_FORWARDING,
2591 PKT_STR, proto, PKT_STR, data, PKT_END);
2592 }
2593 do {
2594 crReturnV;
2595 } while (!ispkt);
2596 if (pktin.type != SSH1_SMSG_SUCCESS
2597 && pktin.type != SSH1_SMSG_FAILURE) {
2598 bombout(("Protocol confusion"));
2599 crReturnV;
2600 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2601 logevent("X11 forwarding refused");
2602 } else {
2603 logevent("X11 forwarding enabled");
9c964e85 2604 ssh_X11_fwd_enabled = TRUE;
2605 }
2606 }
2607
d74d141c 2608 {
2609 char type, *e;
2610 int n;
2611 int sport,dport;
2612 char sports[256], dports[256], host[256];
2613 char buf[1024];
2614
bc240b21 2615 ssh_rportfwds = newtree234(ssh_rportcmp_ssh1);
d74d141c 2616 /* Add port forwardings. */
2617 e = cfg.portfwd;
2618 while (*e) {
2619 type = *e++;
2620 n = 0;
2621 while (*e && *e != '\t')
2622 sports[n++] = *e++;
2623 sports[n] = 0;
2624 if (*e == '\t')
2625 e++;
2626 n = 0;
2627 while (*e && *e != ':')
2628 host[n++] = *e++;
2629 host[n] = 0;
2630 if (*e == ':')
2631 e++;
2632 n = 0;
2633 while (*e)
2634 dports[n++] = *e++;
2635 dports[n] = 0;
2636 e++;
2637 dport = atoi(dports);
2638 sport = atoi(sports);
2639 if (sport && dport) {
2640 if (type == 'L') {
2641 pfd_addforward(host, dport, sport);
2642 sprintf(buf, "Local port %d forwarding to %s:%d",
2643 sport, host, dport);
2644 logevent(buf);
2645 } else {
2646 struct ssh_rportfwd *pf;
2647 pf = smalloc(sizeof(*pf));
bc240b21 2648 strcpy(pf->dhost, host);
2649 pf->dport = dport;
d74d141c 2650 if (add234(ssh_rportfwds, pf) != pf) {
2651 sprintf(buf,
95bc8819 2652 "Duplicate remote port forwarding to %s:%d",
d74d141c 2653 host, dport);
2654 logevent(buf);
bc240b21 2655 sfree(pf);
d74d141c 2656 } else {
2657 sprintf(buf, "Requesting remote port %d forward to %s:%d",
2658 sport, host, dport);
2659 logevent(buf);
2660 send_packet(SSH1_CMSG_PORT_FORWARD_REQUEST,
2661 PKT_INT, sport,
2662 PKT_STR, host,
2663 PKT_INT, dport,
2664 PKT_END);
2665 }
2666 }
2667 }
2668 }
2669 }
2670
fef97f43 2671 if (!cfg.nopty) {
e5574168 2672 send_packet(SSH1_CMSG_REQUEST_PTY,
32874aea 2673 PKT_STR, cfg.termtype,
2674 PKT_INT, rows, PKT_INT, cols,
2675 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
2676 ssh_state = SSH_STATE_INTERMED;
2677 do {
2678 crReturnV;
2679 } while (!ispkt);
2680 if (pktin.type != SSH1_SMSG_SUCCESS
2681 && pktin.type != SSH1_SMSG_FAILURE) {
2682 bombout(("Protocol confusion"));
2683 crReturnV;
2684 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2685 c_write_str("Server refused to allocate pty\r\n");
2686 ssh_editing = ssh_echoing = 1;
2687 }
c5e9c988 2688 logevent("Allocated pty");
0965bee0 2689 } else {
32874aea 2690 ssh_editing = ssh_echoing = 1;
374330e2 2691 }
2692
4ba9b64b 2693 if (cfg.compression) {
32874aea 2694 send_packet(SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
2695 do {
2696 crReturnV;
2697 } while (!ispkt);
2698 if (pktin.type != SSH1_SMSG_SUCCESS
2699 && pktin.type != SSH1_SMSG_FAILURE) {
2700 bombout(("Protocol confusion"));
2701 crReturnV;
2702 } else if (pktin.type == SSH1_SMSG_FAILURE) {
2703 c_write_str("Server refused to compress\r\n");
2704 }
4ba9b64b 2705 logevent("Started compression");
2706 ssh1_compressing = TRUE;
2707 zlib_compress_init();
2708 zlib_decompress_init();
2709 }
2710
fd5e5847 2711 /*
2712 * Start the shell or command.
2713 *
2714 * Special case: if the first-choice command is an SSH2
2715 * subsystem (hence not usable here) and the second choice
2716 * exists, we fall straight back to that.
2717 */
2718 {
2719 char *cmd = cfg.remote_cmd_ptr;
2720
2721 if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) {
2722 cmd = cfg.remote_cmd_ptr2;
2723 ssh_fallback_cmd = TRUE;
2724 }
2725 if (*cmd)
2726 send_packet(SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
2727 else
2728 send_packet(SSH1_CMSG_EXEC_SHELL, PKT_END);
2729 logevent("Started session");
2730 }
374330e2 2731
2732 ssh_state = SSH_STATE_SESSION;
2733 if (size_needed)
2734 ssh_size();
3687d221 2735 if (eof_needed)
32874aea 2736 ssh_special(TS_EOF);
374330e2 2737
32874aea 2738 ldisc_send(NULL, 0); /* cause ldisc to notice changes */
8ccc75b0 2739 ssh_send_ok = 1;
dacbd0e8 2740 ssh_channels = newtree234(ssh_channelcmp);
374330e2 2741 while (1) {
2742 crReturnV;
2743 if (ispkt) {
e5574168 2744 if (pktin.type == SSH1_SMSG_STDOUT_DATA ||
32874aea 2745 pktin.type == SSH1_SMSG_STDERR_DATA) {
fb09bf1c 2746 long len = GET_32BIT(pktin.body);
5471d09a 2747 int bufsize =
2748 from_backend(pktin.type == SSH1_SMSG_STDERR_DATA,
2749 pktin.body + 4, len);
90347b95 2750 if (!ssh1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
5471d09a 2751 ssh1_stdout_throttling = 1;
2752 ssh1_throttle(+1);
2753 }
e5574168 2754 } else if (pktin.type == SSH1_MSG_DISCONNECT) {
32874aea 2755 ssh_state = SSH_STATE_CLOSED;
c5e9c988 2756 logevent("Received disconnect request");
32874aea 2757 crReturnV;
2758 } else if (pktin.type == SSH1_SMSG_X11_OPEN) {
2759 /* Remote side is trying to open a channel to talk to our
2760 * X-Server. Give them back a local channel number. */
2761 struct ssh_channel *c;
9c964e85 2762
2763 logevent("Received X11 connect request");
2764 /* Refuse if X11 forwarding is disabled. */
2765 if (!ssh_X11_fwd_enabled) {
2766 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
32874aea 2767 PKT_INT, GET_32BIT(pktin.body), PKT_END);
9c964e85 2768 logevent("Rejected X11 connect request");
2769 } else {
9c964e85 2770 c = smalloc(sizeof(struct ssh_channel));
2771
32874aea 2772 if (x11_init(&c->u.x11.s, cfg.x11_display, c) != NULL) {
2773 logevent("opening X11 forward connection failed");
2774 sfree(c);
2775 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2776 PKT_INT, GET_32BIT(pktin.body),
2777 PKT_END);
9c964e85 2778 } else {
32874aea 2779 logevent
2780 ("opening X11 forward connection succeeded");
2781 c->remoteid = GET_32BIT(pktin.body);
2782 c->localid = alloc_channel_id();
2783 c->closes = 0;
5471d09a 2784 c->v.v1.throttling = 0;
32874aea 2785 c->type = CHAN_X11; /* identify channel type */
2786 add234(ssh_channels, c);
2787 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2788 PKT_INT, c->remoteid, PKT_INT,
2789 c->localid, PKT_END);
2790 logevent("Opened X11 forward channel");
9c964e85 2791 }
2792 }
32874aea 2793 } else if (pktin.type == SSH1_SMSG_AGENT_OPEN) {
2794 /* Remote side is trying to open a channel to talk to our
2795 * agent. Give them back a local channel number. */
2796 struct ssh_channel *c;
db7d555c 2797
2798 /* Refuse if agent forwarding is disabled. */
2799 if (!ssh_agentfwd_enabled) {
2800 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
32874aea 2801 PKT_INT, GET_32BIT(pktin.body), PKT_END);
db7d555c 2802 } else {
dcbde236 2803 c = smalloc(sizeof(struct ssh_channel));
db7d555c 2804 c->remoteid = GET_32BIT(pktin.body);
d2371c81 2805 c->localid = alloc_channel_id();
db7d555c 2806 c->closes = 0;
5471d09a 2807 c->v.v1.throttling = 0;
32874aea 2808 c->type = CHAN_AGENT; /* identify channel type */
db7d555c 2809 c->u.a.lensofar = 0;
2810 add234(ssh_channels, c);
2811 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2812 PKT_INT, c->remoteid, PKT_INT, c->localid,
2813 PKT_END);
2814 }
d74d141c 2815 } else if (pktin.type == SSH1_MSG_PORT_OPEN) {
2816 /* Remote side is trying to open a channel to talk to a
2817 * forwarded port. Give them back a local channel number. */
2818 struct ssh_channel *c;
2819 struct ssh_rportfwd pf;
2820 int hostsize, port;
2821 char host[256], buf[1024];
2822 char *p, *h, *e;
2823 c = smalloc(sizeof(struct ssh_channel));
2824
2825 hostsize = GET_32BIT(pktin.body+4);
2826 for(h = host, p = pktin.body+8; hostsize != 0; hostsize--) {
2827 if (h+1 < host+sizeof(host))
2828 *h++ = *p;
95bc8819 2829 p++;
d74d141c 2830 }
2831 *h = 0;
2832 port = GET_32BIT(p);
2833
bc240b21 2834 strcpy(pf.dhost, host);
2835 pf.dport = port;
d74d141c 2836
2837 if (find234(ssh_rportfwds, &pf, NULL) == NULL) {
2838 sprintf(buf, "Rejected remote port open request for %s:%d",
2839 host, port);
2840 logevent(buf);
2841 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2842 PKT_INT, GET_32BIT(pktin.body), PKT_END);
2843 } else {
2844 sprintf(buf, "Received remote port open request for %s:%d",
2845 host, port);
2846 logevent(buf);
2847 e = pfd_newconnect(&c->u.pfd.s, host, port, c);
2848 if (e != NULL) {
2849 char buf[256];
2850 sprintf(buf, "Port open failed: %s", e);
2851 logevent(buf);
2852 sfree(c);
2853 send_packet(SSH1_MSG_CHANNEL_OPEN_FAILURE,
2854 PKT_INT, GET_32BIT(pktin.body),
2855 PKT_END);
2856 } else {
2857 c->remoteid = GET_32BIT(pktin.body);
2858 c->localid = alloc_channel_id();
2859 c->closes = 0;
5471d09a 2860 c->v.v1.throttling = 0;
d74d141c 2861 c->type = CHAN_SOCKDATA; /* identify channel type */
2862 add234(ssh_channels, c);
2863 send_packet(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
2864 PKT_INT, c->remoteid, PKT_INT,
2865 c->localid, PKT_END);
2866 logevent("Forwarded port opened successfully");
2867 }
2868 }
2869
2870 } else if (pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
bc240b21 2871 unsigned int remoteid = GET_32BIT(pktin.body);
2872 unsigned int localid = GET_32BIT(pktin.body+4);
2873 struct ssh_channel *c;
2874
2875 c = find234(ssh_channels, &remoteid, ssh_channelfind);
2876 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
2877 c->remoteid = localid;
2878 c->type = CHAN_SOCKDATA;
2879 pfd_confirm(c->u.pfd.s);
2880 }
d74d141c 2881
724cface 2882 } else if (pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
2883 unsigned int remoteid = GET_32BIT(pktin.body);
2884 unsigned int localid = GET_32BIT(pktin.body+4);
2885 struct ssh_channel *c;
2886
2887 c = find234(ssh_channels, &remoteid, ssh_channelfind);
2888 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
2889 logevent("Forwarded connection refused by server");
2890 pfd_close(c->u.pfd.s);
2891 del234(ssh_channels, c);
2892 sfree(c);
2893 }
2894
db7d555c 2895 } else if (pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
2896 pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
32874aea 2897 /* Remote side closes a channel. */
2898 unsigned i = GET_32BIT(pktin.body);
2899 struct ssh_channel *c;
2900 c = find234(ssh_channels, &i, ssh_channelfind);
2901 if (c) {
2902 int closetype;
2903 closetype =
2904 (pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
2905 if (!(c->closes & closetype))
2906 send_packet(pktin.type, PKT_INT, c->remoteid,
2907 PKT_END);
783415f8 2908 if ((c->closes == 0) && (c->type == CHAN_X11)) {
d74d141c 2909 logevent("Forwarded X11 connection terminated");
9c964e85 2910 assert(c->u.x11.s != NULL);
2911 x11_close(c->u.x11.s);
2912 c->u.x11.s = NULL;
2913 }
d74d141c 2914 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
2915 logevent("Forwarded port closed");
2916 assert(c->u.pfd.s != NULL);
2917 pfd_close(c->u.pfd.s);
2918 c->u.pfd.s = NULL;
2919 }
32874aea 2920 c->closes |= closetype;
2921 if (c->closes == 3) {
2922 del234(ssh_channels, c);
2923 sfree(c);
2924 }
2925 }
2926 } else if (pktin.type == SSH1_MSG_CHANNEL_DATA) {
2927 /* Data sent down one of our channels. */
2928 int i = GET_32BIT(pktin.body);
2929 int len = GET_32BIT(pktin.body + 4);
2930 unsigned char *p = pktin.body + 8;
2931 struct ssh_channel *c;
2932 c = find234(ssh_channels, &i, ssh_channelfind);
2933 if (c) {
5471d09a 2934 int bufsize;
32874aea 2935 switch (c->type) {
2936 case CHAN_X11:
5471d09a 2937 bufsize = x11_send(c->u.x11.s, p, len);
9c964e85 2938 break;
d74d141c 2939 case CHAN_SOCKDATA:
5471d09a 2940 bufsize = pfd_send(c->u.pfd.s, p, len);
bc240b21 2941 break;
32874aea 2942 case CHAN_AGENT:
2943 /* Data for an agent message. Buffer it. */
2944 while (len > 0) {
2945 if (c->u.a.lensofar < 4) {
2946 int l = min(4 - c->u.a.lensofar, len);
2947 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
2948 l);
2949 p += l;
2950 len -= l;
2951 c->u.a.lensofar += l;
2952 }
2953 if (c->u.a.lensofar == 4) {
2954 c->u.a.totallen =
2955 4 + GET_32BIT(c->u.a.msglen);
2956 c->u.a.message = smalloc(c->u.a.totallen);
2957 memcpy(c->u.a.message, c->u.a.msglen, 4);
2958 }
2959 if (c->u.a.lensofar >= 4 && len > 0) {
2960 int l =
2961 min(c->u.a.totallen - c->u.a.lensofar,
2962 len);
2963 memcpy(c->u.a.message + c->u.a.lensofar, p,
2964 l);
2965 p += l;
2966 len -= l;
2967 c->u.a.lensofar += l;
2968 }
2969 if (c->u.a.lensofar == c->u.a.totallen) {
2970 void *reply, *sentreply;
2971 int replylen;
2972 agent_query(c->u.a.message,
2973 c->u.a.totallen, &reply,
2974 &replylen);
2975 if (reply)
2976 sentreply = reply;
2977 else {
2978 /* Fake SSH_AGENT_FAILURE. */
2979 sentreply = "\0\0\0\1\5";
2980 replylen = 5;
2981 }
2982 send_packet(SSH1_MSG_CHANNEL_DATA,
2983 PKT_INT, c->remoteid,
2984 PKT_INT, replylen,
2985 PKT_DATA, sentreply, replylen,
2986 PKT_END);
2987 if (reply)
2988 sfree(reply);
2989 sfree(c->u.a.message);
2990 c->u.a.lensofar = 0;
2991 }
2992 }
5471d09a 2993 bufsize = 0; /* agent channels never back up */
32874aea 2994 break;
2995 }
90347b95 2996 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
5471d09a 2997 c->v.v1.throttling = 1;
2998 ssh1_throttle(+1);
2999 }
32874aea 3000 }
e5574168 3001 } else if (pktin.type == SSH1_SMSG_SUCCESS) {
972a41c8 3002 /* may be from EXEC_SHELL on some servers */
e5574168 3003 } else if (pktin.type == SSH1_SMSG_FAILURE) {
972a41c8 3004 /* may be from EXEC_SHELL on some servers
374330e2 3005 * if no pty is available or in other odd cases. Ignore */
e5574168 3006 } else if (pktin.type == SSH1_SMSG_EXIT_STATUS) {
3007 send_packet(SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
374330e2 3008 } else {
8d5de777 3009 bombout(("Strange packet received: type %d", pktin.type));
32874aea 3010 crReturnV;
374330e2 3011 }
3012 } else {
8df7a775 3013 while (inlen > 0) {
3014 int len = min(inlen, 512);
3015 send_packet(SSH1_CMSG_STDIN_DATA,
3016 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3017 in += len;
3018 inlen -= len;
3019 }
374330e2 3020 }
3021 }
3022
3023 crFinishV;
3024}
3025
3026/*
e5574168 3027 * Utility routine for decoding comma-separated strings in KEXINIT.
3028 */
32874aea 3029static int in_commasep_string(char *needle, char *haystack, int haylen)
3030{
e5574168 3031 int needlen = strlen(needle);
3032 while (1) {
32874aea 3033 /*
3034 * Is it at the start of the string?
3035 */
3036 if (haylen >= needlen && /* haystack is long enough */
3037 !memcmp(needle, haystack, needlen) && /* initial match */
3038 (haylen == needlen || haystack[needlen] == ',')
3039 /* either , or EOS follows */
3040 )
3041 return 1;
3042 /*
3043 * If not, search for the next comma and resume after that.
3044 * If no comma found, terminate.
3045 */
3046 while (haylen > 0 && *haystack != ',')
3047 haylen--, haystack++;
3048 if (haylen == 0)
3049 return 0;
3050 haylen--, haystack++; /* skip over comma itself */
e5574168 3051 }
3052}
3053
3054/*
d39f364a 3055 * SSH2 key creation method.
3056 */
32874aea 3057static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr,
3058 char *keyspace)
3059{
d39f364a 3060 SHA_State s;
3061 /* First 20 bytes. */
3062 SHA_Init(&s);
3063 sha_mpint(&s, K);
3064 SHA_Bytes(&s, H, 20);
3065 SHA_Bytes(&s, &chr, 1);
5e0d7cb8 3066 SHA_Bytes(&s, sessid, 20);
d39f364a 3067 SHA_Final(&s, keyspace);
3068 /* Next 20 bytes. */
3069 SHA_Init(&s);
3070 sha_mpint(&s, K);
3071 SHA_Bytes(&s, H, 20);
3072 SHA_Bytes(&s, keyspace, 20);
32874aea 3073 SHA_Final(&s, keyspace + 20);
d39f364a 3074}
3075
3076/*
7cca0d81 3077 * Handle the SSH2 transport layer.
e5574168 3078 */
7cca0d81 3079static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
e5574168 3080{
ca20bfcf 3081 static int i, j, len, nbits, pbits, warn;
e5574168 3082 static char *str;
a92dd380 3083 static Bignum p, g, e, f, K;
3084 static int kex_init_value, kex_reply_value;
7591b9ff 3085 static const struct ssh_mac **maclist;
8b2715b2 3086 static int nmacs;
0a3f1d48 3087 static const struct ssh2_cipher *cscipher_tobe = NULL;
3088 static const struct ssh2_cipher *sccipher_tobe = NULL;
57476f6b 3089 static const struct ssh_mac *csmac_tobe = NULL;
3090 static const struct ssh_mac *scmac_tobe = NULL;
3091 static const struct ssh_compress *cscomp_tobe = NULL;
3092 static const struct ssh_compress *sccomp_tobe = NULL;
d5859615 3093 static char *hostkeydata, *sigdata, *keystr, *fingerprint;
e5574168 3094 static int hostkeylen, siglen;
e055a386 3095 static void *hkey; /* actual host key */
e5574168 3096 static unsigned char exchange_hash[20];
d39f364a 3097 static unsigned char keyspace[40];
ca20bfcf 3098 static int n_preferred_ciphers;
3099 static const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
4ba9b64b 3100 static const struct ssh_compress *preferred_comp;
0db56f73 3101 static int first_kex;
e5574168 3102
3103 crBegin;
7cca0d81 3104 random_init();
0db56f73 3105 first_kex = 1;
e5574168 3106
5e8358ad 3107 /*
ca20bfcf 3108 * Set up the preferred ciphers. (NULL => warn below here)
5e8358ad 3109 */
ca20bfcf 3110 n_preferred_ciphers = 0;
3111 for (i = 0; i < CIPHER_MAX; i++) {
3112 switch (cfg.ssh_cipherlist[i]) {
3113 case CIPHER_BLOWFISH:
3114 preferred_ciphers[n_preferred_ciphers] = &ssh2_blowfish;
3115 n_preferred_ciphers++;
3116 break;
3117 case CIPHER_DES:
3118 /* Not supported in SSH2; silently drop */
3119 break;
3120 case CIPHER_3DES:
3121 preferred_ciphers[n_preferred_ciphers] = &ssh2_3des;
3122 n_preferred_ciphers++;
3123 break;
3124 case CIPHER_AES:
3125 preferred_ciphers[n_preferred_ciphers] = &ssh2_aes;
3126 n_preferred_ciphers++;
3127 break;
3128 case CIPHER_WARN:
3129 /* Flag for later. Don't bother if it's the last in
3130 * the list. */
3131 if (i < CIPHER_MAX - 1) {
3132 preferred_ciphers[n_preferred_ciphers] = NULL;
3133 n_preferred_ciphers++;
3134 }
3135 break;
3136 }
5e8358ad 3137 }
ca20bfcf 3138
3139 /*
3140 * Set up preferred compression.
3141 */
4ba9b64b 3142 if (cfg.compression)
3143 preferred_comp = &ssh_zlib;
3144 else
3145 preferred_comp = &ssh_comp_none;
5e8358ad 3146
7591b9ff 3147 /*
3148 * Be prepared to work around the buggy MAC problem.
3149 */
7d503c31 3150 if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC))
32874aea 3151 maclist = buggymacs, nmacs = lenof(buggymacs);
7591b9ff 3152 else
32874aea 3153 maclist = macs, nmacs = lenof(macs);
7591b9ff 3154
32874aea 3155 begin_key_exchange:
e5574168 3156 /*
3157 * Construct and send our key exchange packet.
3158 */
3159 ssh2_pkt_init(SSH2_MSG_KEXINIT);
3160 for (i = 0; i < 16; i++)
32874aea 3161 ssh2_pkt_addbyte((unsigned char) random_byte());
e5574168 3162 /* List key exchange algorithms. */
3163 ssh2_pkt_addstring_start();
3164 for (i = 0; i < lenof(kex_algs); i++) {
32874aea 3165 ssh2_pkt_addstring_str(kex_algs[i]->name);
3166 if (i < lenof(kex_algs) - 1)
3167 ssh2_pkt_addstring_str(",");
e5574168 3168 }
3169 /* List server host key algorithms. */
3170 ssh2_pkt_addstring_start();
3171 for (i = 0; i < lenof(hostkey_algs); i++) {
32874aea 3172 ssh2_pkt_addstring_str(hostkey_algs[i]->name);
3173 if (i < lenof(hostkey_algs) - 1)
3174 ssh2_pkt_addstring_str(",");
e5574168 3175 }
3176 /* List client->server encryption algorithms. */
3177 ssh2_pkt_addstring_start();
ca20bfcf 3178 for (i = 0; i < n_preferred_ciphers; i++) {
3179 const struct ssh2_ciphers *c = preferred_ciphers[i];
3180 if (!c) continue; /* warning flag */
32874aea 3181 for (j = 0; j < c->nciphers; j++) {
3182 ssh2_pkt_addstring_str(c->list[j]->name);
ca20bfcf 3183 if (i < n_preferred_ciphers || j < c->nciphers - 1)
32874aea 3184 ssh2_pkt_addstring_str(",");
3185 }
e5574168 3186 }
3187 /* List server->client encryption algorithms. */
3188 ssh2_pkt_addstring_start();
ca20bfcf 3189 for (i = 0; i < n_preferred_ciphers; i++) {
3190 const struct ssh2_ciphers *c = preferred_ciphers[i];
3191 if (!c) continue; /* warning flag */
32874aea 3192 for (j = 0; j < c->nciphers; j++) {
3193 ssh2_pkt_addstring_str(c->list[j]->name);
ca20bfcf 3194 if (i < n_preferred_ciphers || j < c->nciphers - 1)
32874aea 3195 ssh2_pkt_addstring_str(",");
3196 }
e5574168 3197 }
3198 /* List client->server MAC algorithms. */
3199 ssh2_pkt_addstring_start();
8b2715b2 3200 for (i = 0; i < nmacs; i++) {
32874aea 3201 ssh2_pkt_addstring_str(maclist[i]->name);
3202 if (i < nmacs - 1)
3203 ssh2_pkt_addstring_str(",");
e5574168 3204 }
3205 /* List server->client MAC algorithms. */
3206 ssh2_pkt_addstring_start();
8b2715b2 3207 for (i = 0; i < nmacs; i++) {
32874aea 3208 ssh2_pkt_addstring_str(maclist[i]->name);
3209 if (i < nmacs - 1)
3210 ssh2_pkt_addstring_str(",");
e5574168 3211 }
3212 /* List client->server compression algorithms. */
3213 ssh2_pkt_addstring_start();
32874aea 3214 for (i = 0; i < lenof(compressions) + 1; i++) {
3215 const struct ssh_compress *c =
3216 i == 0 ? preferred_comp : compressions[i - 1];
3217 ssh2_pkt_addstring_str(c->name);
3218 if (i < lenof(compressions))
3219 ssh2_pkt_addstring_str(",");
e5574168 3220 }
3221 /* List server->client compression algorithms. */
3222 ssh2_pkt_addstring_start();
32874aea 3223 for (i = 0; i < lenof(compressions) + 1; i++) {
3224 const struct ssh_compress *c =
3225 i == 0 ? preferred_comp : compressions[i - 1];
3226 ssh2_pkt_addstring_str(c->name);
3227 if (i < lenof(compressions))
3228 ssh2_pkt_addstring_str(",");
e5574168 3229 }
3230 /* List client->server languages. Empty list. */
3231 ssh2_pkt_addstring_start();
3232 /* List server->client languages. Empty list. */
3233 ssh2_pkt_addstring_start();
3234 /* First KEX packet does _not_ follow, because we're not that brave. */
3235 ssh2_pkt_addbool(FALSE);
3236 /* Reserved. */
3237 ssh2_pkt_adduint32(0);
0db56f73 3238
3239 exhash = exhashbase;
32874aea 3240 sha_string(&exhash, pktout.data + 5, pktout.length - 5);
0db56f73 3241
e5574168 3242 ssh2_pkt_send();
3243
32874aea 3244 if (!ispkt)
3245 crWaitUntil(ispkt);
3246 sha_string(&exhash, pktin.data + 5, pktin.length - 5);
e5574168 3247
3248 /*
3249 * Now examine the other side's KEXINIT to see what we're up
3250 * to.
3251 */
7cca0d81 3252 if (pktin.type != SSH2_MSG_KEXINIT) {
32874aea 3253 bombout(("expected key exchange packet from server"));
3254 crReturn(0);
7cca0d81 3255 }
32874aea 3256 kex = NULL;
3257 hostkey = NULL;
3258 cscipher_tobe = NULL;
3259 sccipher_tobe = NULL;
3260 csmac_tobe = NULL;
3261 scmac_tobe = NULL;
3262 cscomp_tobe = NULL;
3263 sccomp_tobe = NULL;
3264 pktin.savedpos += 16; /* skip garbage cookie */
e5574168 3265 ssh2_pkt_getstring(&str, &len); /* key exchange algorithms */
3266 for (i = 0; i < lenof(kex_algs); i++) {
32874aea 3267 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3268 kex = kex_algs[i];
3269 break;
3270 }
e5574168 3271 }
3272 ssh2_pkt_getstring(&str, &len); /* host key algorithms */
3273 for (i = 0; i < lenof(hostkey_algs); i++) {
32874aea 3274 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3275 hostkey = hostkey_algs[i];
3276 break;
3277 }
e5574168 3278 }
3279 ssh2_pkt_getstring(&str, &len); /* client->server cipher */
ca20bfcf 3280 warn = 0;
3281 for (i = 0; i < n_preferred_ciphers; i++) {
3282 const struct ssh2_ciphers *c = preferred_ciphers[i];
3283 if (!c) {
3284 warn = 1;
3285 } else {
3286 for (j = 0; j < c->nciphers; j++) {
3287 if (in_commasep_string(c->list[j]->name, str, len)) {
3288 cscipher_tobe = c->list[j];
3289 break;
3290 }
32874aea 3291 }
3292 }
ca20bfcf 3293 if (cscipher_tobe) {
3294 if (warn)
3295 askcipher(cscipher_tobe->name, 1);
32874aea 3296 break;
ca20bfcf 3297 }
e5574168 3298 }
3299 ssh2_pkt_getstring(&str, &len); /* server->client cipher */
ca20bfcf 3300 warn = 0;
3301 for (i = 0; i < n_preferred_ciphers; i++) {
3302 const struct ssh2_ciphers *c = preferred_ciphers[i];
3303 if (!c) {
3304 warn = 1;
3305 } else {
3306 for (j = 0; j < c->nciphers; j++) {
3307 if (in_commasep_string(c->list[j]->name, str, len)) {
3308 sccipher_tobe = c->list[j];
3309 break;
3310 }
32874aea 3311 }
3312 }
ca20bfcf 3313 if (sccipher_tobe) {
3314 if (warn)
3315 askcipher(sccipher_tobe->name, 2);
32874aea 3316 break;
ca20bfcf 3317 }
e5574168 3318 }
3319 ssh2_pkt_getstring(&str, &len); /* client->server mac */
8b2715b2 3320 for (i = 0; i < nmacs; i++) {
32874aea 3321 if (in_commasep_string(maclist[i]->name, str, len)) {
3322 csmac_tobe = maclist[i];
3323 break;
3324 }
e5574168 3325 }
3326 ssh2_pkt_getstring(&str, &len); /* server->client mac */
8b2715b2 3327 for (i = 0; i < nmacs; i++) {
32874aea 3328 if (in_commasep_string(maclist[i]->name, str, len)) {
3329 scmac_tobe = maclist[i];
3330 break;
3331 }
e5574168 3332 }
3333 ssh2_pkt_getstring(&str, &len); /* client->server compression */
32874aea 3334 for (i = 0; i < lenof(compressions) + 1; i++) {
3335 const struct ssh_compress *c =
3336 i == 0 ? preferred_comp : compressions[i - 1];
3337 if (in_commasep_string(c->name, str, len)) {
3338 cscomp_tobe = c;
3339 break;
3340 }
e5574168 3341 }
3342 ssh2_pkt_getstring(&str, &len); /* server->client compression */
32874aea 3343 for (i = 0; i < lenof(compressions) + 1; i++) {
3344 const struct ssh_compress *c =
3345 i == 0 ? preferred_comp : compressions[i - 1];
3346 if (in_commasep_string(c->name, str, len)) {
3347 sccomp_tobe = c;
3348 break;
3349 }
e5574168 3350 }
e5574168 3351
3352 /*
7bd5a860 3353 * Work out the number of bits of key we will need from the key
3354 * exchange. We start with the maximum key length of either
3355 * cipher...
3356 */
3357 {
32874aea 3358 int csbits, scbits;
7bd5a860 3359
3360 csbits = cscipher_tobe->keylen;
3361 scbits = sccipher_tobe->keylen;
3362 nbits = (csbits > scbits ? csbits : scbits);
3363 }
3364 /* The keys only have 160-bit entropy, since they're based on
3365 * a SHA-1 hash. So cap the key size at 160 bits. */
32874aea 3366 if (nbits > 160)
3367 nbits = 160;
7bd5a860 3368
3369 /*
a92dd380 3370 * If we're doing Diffie-Hellman group exchange, start by
3371 * requesting a group.
e5574168 3372 */
a92dd380 3373 if (kex == &ssh_diffiehellman_gex) {
32874aea 3374 logevent("Doing Diffie-Hellman group exchange");
3375 /*
3376 * Work out how big a DH group we will need to allow that
3377 * much data.
7bd5a860 3378 */
32874aea 3379 pbits = 512 << ((nbits - 1) / 64);
3380 ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
3381 ssh2_pkt_adduint32(pbits);
3382 ssh2_pkt_send();
3383
3384 crWaitUntil(ispkt);
3385 if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
3386 bombout(("expected key exchange group packet from server"));
3387 crReturn(0);
3388 }
3389 p = ssh2_pkt_getmp();
3390 g = ssh2_pkt_getmp();
3391 dh_setup_group(p, g);
3392 kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
3393 kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
a92dd380 3394 } else {
32874aea 3395 dh_setup_group1();
3396 kex_init_value = SSH2_MSG_KEXDH_INIT;
3397 kex_reply_value = SSH2_MSG_KEXDH_REPLY;
8d5de777 3398 }
e5574168 3399
a92dd380 3400 logevent("Doing Diffie-Hellman key exchange");
e5574168 3401 /*
a92dd380 3402 * Now generate and send e for Diffie-Hellman.
e5574168 3403 */
32874aea 3404 e = dh_create_e(nbits * 2);
a92dd380 3405 ssh2_pkt_init(kex_init_value);
e5574168 3406 ssh2_pkt_addmp(e);
3407 ssh2_pkt_send();
3408
3409 crWaitUntil(ispkt);
a92dd380 3410 if (pktin.type != kex_reply_value) {
32874aea 3411 bombout(("expected key exchange reply packet from server"));
3412 crReturn(0);
7cca0d81 3413 }
e5574168 3414 ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
3415 f = ssh2_pkt_getmp();
e5574168 3416 ssh2_pkt_getstring(&sigdata, &siglen);
3417
3418 K = dh_find_K(f);
e5574168 3419
3420 sha_string(&exhash, hostkeydata, hostkeylen);
a92dd380 3421 if (kex == &ssh_diffiehellman_gex) {
32874aea 3422 sha_uint32(&exhash, pbits);
3423 sha_mpint(&exhash, p);
3424 sha_mpint(&exhash, g);
a92dd380 3425 }
e5574168 3426 sha_mpint(&exhash, e);
3427 sha_mpint(&exhash, f);
3428 sha_mpint(&exhash, K);
3429 SHA_Final(&exhash, exchange_hash);
3430
3709bfe9 3431 dh_cleanup();
3432
7cca0d81 3433#if 0
765c4200 3434 debug(("Exchange hash is:\n"));
3435 dmemdump(exchange_hash, 20);
7cca0d81 3436#endif
3437
e055a386 3438 hkey = hostkey->newkey(hostkeydata, hostkeylen);
f7259d10 3439 if (!hkey ||
3440 !hostkey->verifysig(hkey, sigdata, siglen, exchange_hash, 20)) {
3441 bombout(("Server's host key did not match the signature supplied"));
32874aea 3442 crReturn(0);
8d5de777 3443 }
e5574168 3444
3445 /*
7cca0d81 3446 * Expect SSH2_MSG_NEWKEYS from server.
d39f364a 3447 */
7cca0d81 3448 crWaitUntil(ispkt);
8d5de777 3449 if (pktin.type != SSH2_MSG_NEWKEYS) {
32874aea 3450 bombout(("expected new-keys packet from server"));
3451 crReturn(0);
8d5de777 3452 }
d39f364a 3453
3454 /*
7cca0d81 3455 * Authenticate remote host: verify host key. (We've already
3456 * checked the signature of the exchange hash.)
e5574168 3457 */
e055a386 3458 keystr = hostkey->fmtkey(hkey);
3459 fingerprint = hostkey->fingerprint(hkey);
d4857987 3460 verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
32874aea 3461 keystr, fingerprint);
3462 if (first_kex) { /* don't bother logging this in rekeys */
5e0d7cb8 3463 logevent("Host key fingerprint is:");
3464 logevent(fingerprint);
3465 }
dcbde236 3466 sfree(fingerprint);
3467 sfree(keystr);
e055a386 3468 hostkey->freekey(hkey);
d39f364a 3469
3470 /*
7cca0d81 3471 * Send SSH2_MSG_NEWKEYS.
d39f364a 3472 */
3473 ssh2_pkt_init(SSH2_MSG_NEWKEYS);
3474 ssh2_pkt_send();
d39f364a 3475
3476 /*
3477 * Create and initialise session keys.
3478 */
3479 cscipher = cscipher_tobe;
3480 sccipher = sccipher_tobe;
3481 csmac = csmac_tobe;
3482 scmac = scmac_tobe;
3483 cscomp = cscomp_tobe;
3484 sccomp = sccomp_tobe;
4ba9b64b 3485 cscomp->compress_init();
3486 sccomp->decompress_init();
d39f364a 3487 /*
5e0d7cb8 3488 * Set IVs after keys. Here we use the exchange hash from the
3489 * _first_ key exchange.
d39f364a 3490 */
5e0d7cb8 3491 if (first_kex)
65a22376 3492 memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash));
3493 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace);
5e0d7cb8 3494 cscipher->setcskey(keyspace);
65a22376 3495 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace);
5e0d7cb8 3496 sccipher->setsckey(keyspace);
65a22376 3497 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace);
5e0d7cb8 3498 cscipher->setcsiv(keyspace);
65a22376 3499 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace);
5e0d7cb8 3500 sccipher->setsciv(keyspace);
65a22376 3501 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace);
5e0d7cb8 3502 csmac->setcskey(keyspace);
65a22376 3503 ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace);
5e0d7cb8 3504 scmac->setsckey(keyspace);
d39f364a 3505
033b4cef 3506 /*
0db56f73 3507 * If this is the first key exchange phase, we must pass the
3508 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
3509 * wants to see it but because it will need time to initialise
3510 * itself before it sees an actual packet. In subsequent key
3511 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
3512 * it would only confuse the layer above.
3513 */
3514 if (!first_kex) {
32874aea 3515 crReturn(0);
0db56f73 3516 }
3517 first_kex = 0;
3518
3519 /*
7cca0d81 3520 * Now we're encrypting. Begin returning 1 to the protocol main
3521 * function so that other things can run on top of the
3522 * transport. If we ever see a KEXINIT, we must go back to the
3523 * start.
033b4cef 3524 */
e96adf72 3525 while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) {
32874aea 3526 crReturn(1);
e96adf72 3527 }
5e0d7cb8 3528 logevent("Server initiated key re-exchange");
7cca0d81 3529 goto begin_key_exchange;
e5574168 3530
3531 crFinish(1);
3532}
3533
7cca0d81 3534/*
783415f8 3535 * Add data to an SSH2 channel output buffer.
3536 */
32874aea 3537static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
3538 int len)
3539{
5471d09a 3540 bufchain_add(&c->v.v2.outbuffer, buf, len);
783415f8 3541}
3542
3543/*
3544 * Attempt to send data on an SSH2 channel.
3545 */
5471d09a 3546static int ssh2_try_send(struct ssh_channel *c)
32874aea 3547{
5471d09a 3548 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
3549 int len;
3550 void *data;
3551 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
3552 if ((unsigned)len > c->v.v2.remwindow)
3553 len = c->v.v2.remwindow;
3554 if ((unsigned)len > c->v.v2.remmaxpkt)
3555 len = c->v.v2.remmaxpkt;
32874aea 3556 ssh2_pkt_init(SSH2_MSG_CHANNEL_DATA);
3557 ssh2_pkt_adduint32(c->remoteid);
3558 ssh2_pkt_addstring_start();
5471d09a 3559 ssh2_pkt_addstring_data(data, len);
32874aea 3560 ssh2_pkt_send();
5471d09a 3561 bufchain_consume(&c->v.v2.outbuffer, len);
3562 c->v.v2.remwindow -= len;
3563 }
3564
3565 /*
3566 * After having sent as much data as we can, return the amount
3567 * still buffered.
3568 */
3569 return bufchain_size(&c->v.v2.outbuffer);
3570}
3571
3572/*
3573 * Potentially enlarge the window on an SSH2 channel.
3574 */
3575static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
3576{
3577 if (newwin > c->v.v2.locwindow) {
3578 ssh2_pkt_init(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
3579 ssh2_pkt_adduint32(c->remoteid);
3580 ssh2_pkt_adduint32(newwin - c->v.v2.locwindow);
3581 ssh2_pkt_send();
3582 c->v.v2.locwindow = newwin;
783415f8 3583 }
3584}
3585
3586/*
7cca0d81 3587 * Handle the SSH2 userauth and connection layers.
3588 */
3589static void do_ssh2_authconn(unsigned char *in, int inlen, int ispkt)
3590{
65a22376 3591 static enum {
32874aea 3592 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
761187b6 3593 AUTH_PASSWORD,
3594 AUTH_KEYBOARD_INTERACTIVE
65a22376 3595 } method;
1408a877 3596 static enum {
32874aea 3597 AUTH_TYPE_NONE,
3598 AUTH_TYPE_PUBLICKEY,
3599 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
3600 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
761187b6 3601 AUTH_TYPE_PASSWORD,
4bdf7c46 3602 AUTH_TYPE_KEYBOARD_INTERACTIVE,
3603 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
1408a877 3604 } type;
761187b6 3605 static int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
3606 static int tried_pubkey_config, tried_agent, tried_keyb_inter;
b3186d64 3607 static int kbd_inter_running;
1408a877 3608 static int we_are_in;
761187b6 3609 static int num_prompts, echo;
65a22376 3610 static char username[100];
3611 static char pwprompt[200];
3612 static char password[100];
7cca0d81 3613
e5574168 3614 crBegin;
3615
7cca0d81 3616 /*
3617 * Request userauth protocol, and await a response to it.
3618 */
3619 ssh2_pkt_init(SSH2_MSG_SERVICE_REQUEST);
3620 ssh2_pkt_addstring("ssh-userauth");
3621 ssh2_pkt_send();
3622 crWaitUntilV(ispkt);
8d5de777 3623 if (pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
32874aea 3624 bombout(("Server refused user authentication protocol"));
3625 crReturnV;
8d5de777 3626 }
7cca0d81 3627
3628 /*
1408a877 3629 * We repeat this whole loop, including the username prompt,
3630 * until we manage a successful authentication. If the user
3631 * types the wrong _password_, they are sent back to the
3632 * beginning to try another username. (If they specify a
3633 * username in the config, they are never asked, even if they
3634 * do give a wrong password.)
3635 *
3636 * I think this best serves the needs of
3637 *
3638 * - the people who have no configuration, no keys, and just
3639 * want to try repeated (username,password) pairs until they
3640 * type both correctly
3641 *
3642 * - people who have keys and configuration but occasionally
3643 * need to fall back to passwords
3644 *
3645 * - people with a key held in Pageant, who might not have
3646 * logged in to a particular machine before; so they want to
3647 * type a username, and then _either_ their key will be
3648 * accepted, _or_ they will type a password. If they mistype
3649 * the username they will want to be able to get back and
3650 * retype it!
7cca0d81 3651 */
1408a877 3652 do {
3653 static int pos;
7cca0d81 3654 static char c;
e5574168 3655
1408a877 3656 /*
3657 * Get a username.
3658 */
3659 pos = 0;
67779be7 3660 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
32874aea 3661 if (ssh_get_line) {
3662 if (!ssh_get_line("login as: ",
3663 username, sizeof(username), FALSE)) {
3664 /*
3665 * get_line failed to get a username.
3666 * Terminate.
3667 */
3668 logevent("No username provided. Abandoning session.");
3669 ssh_state = SSH_STATE_CLOSED;
3670 crReturnV;
3671 }
3672 } else {
3673 c_write_str("login as: ");
3674 ssh_send_ok = 1;
3675 while (pos >= 0) {
3676 crWaitUntilV(!ispkt);
3677 while (inlen--)
3678 switch (c = *in++) {
3679 case 10:
3680 case 13:
3681 username[pos] = 0;
3682 pos = -1;
3683 break;
3684 case 8:
3685 case 127:
3686 if (pos > 0) {
3687 c_write_str("\b \b");
3688 pos--;
3689 }
3690 break;
3691 case 21:
3692 case 27:
3693 while (pos > 0) {
3694 c_write_str("\b \b");
3695 pos--;
3696 }
3697 break;
3698 case 3:
3699 case 4:
3700 random_save_seed();
3701 exit(0);
3702 break;
3703 default:
3704 if (((c >= ' ' && c <= '~') ||
51b2fb65 3705 ((unsigned char) c >= 160))
3706 && pos < sizeof(username)-1) {
32874aea 3707 username[pos++] = c;
3708 c_write(&c, 1);
3709 }
3710 break;
3711 }
3712 }
3713 }
1408a877 3714 c_write_str("\r\n");
7cca0d81 3715 username[strcspn(username, "\n\r")] = '\0';
3716 } else {
3717 char stuff[200];
3718 strncpy(username, cfg.username, 99);
3719 username[99] = '\0';
65a22376 3720 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
7cca0d81 3721 sprintf(stuff, "Using username \"%s\".\r\n", username);
1408a877 3722 c_write_str(stuff);
7cca0d81 3723 }
3724 }
3725
65a22376 3726 /*
1408a877 3727 * Send an authentication request using method "none": (a)
3728 * just in case it succeeds, and (b) so that we know what
3729 * authentication methods we can usefully try next.
65a22376 3730 */
1408a877 3731 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3732 ssh2_pkt_addstring(username);
32874aea 3733 ssh2_pkt_addstring("ssh-connection"); /* service requested */
1408a877 3734 ssh2_pkt_addstring("none"); /* method */
3735 ssh2_pkt_send();
3736 type = AUTH_TYPE_NONE;
3737 gotit = FALSE;
3738 we_are_in = FALSE;
7cca0d81 3739
1408a877 3740 tried_pubkey_config = FALSE;
1983e559 3741 tried_agent = FALSE;
b3186d64 3742 tried_keyb_inter = FALSE;
3743 kbd_inter_running = FALSE;
65a22376 3744
1408a877 3745 while (1) {
3746 /*
3747 * Wait for the result of the last authentication request.
3748 */
3749 if (!gotit)
3750 crWaitUntilV(ispkt);
3751 while (pktin.type == SSH2_MSG_USERAUTH_BANNER) {
32874aea 3752 char *banner;
3753 int size;
3754 /*
3755 * Don't show the banner if we're operating in
3756 * non-verbose non-interactive mode. (It's probably
3757 * a script, which means nobody will read the
3758 * banner _anyway_, and moreover the printing of
3759 * the banner will screw up processing on the
3760 * output of (say) plink.)
3761 */
3762 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
3763 ssh2_pkt_getstring(&banner, &size);
3764 if (banner)
3765 c_write_untrusted(banner, size);
3766 }
1408a877 3767 crWaitUntilV(ispkt);
3768 }
3769 if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
3770 logevent("Access granted");
3771 we_are_in = TRUE;
3772 break;
3773 }
65a22376 3774
b3186d64 3775 if (kbd_inter_running &&
3776 pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
3777 /*
3778 * This is a further prompt in keyboard-interactive
3779 * authentication. Do nothing.
3780 */
6bb26b30 3781 } else if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
b3186d64 3782 bombout(("Strange packet received during authentication: type %d",
1408a877 3783 pktin.type));
38c4a8da 3784 crReturnV;
65a22376 3785 }
3786
1408a877 3787 gotit = FALSE;
65a22376 3788
1408a877 3789 /*
3790 * OK, we're now sitting on a USERAUTH_FAILURE message, so
3791 * we can look at the string in it and know what we can
3792 * helpfully try next.
3793 */
b3186d64 3794 if (pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
1408a877 3795 char *methods;
3796 int methlen;
3797 ssh2_pkt_getstring(&methods, &methlen);
b3186d64 3798 kbd_inter_running = FALSE;
1408a877 3799 if (!ssh2_pkt_getbool()) {
3800 /*
3801 * We have received an unequivocal Access
3802 * Denied. This can translate to a variety of
3803 * messages:
3804 *
3805 * - if we'd just tried "none" authentication,
3806 * it's not worth printing anything at all
3807 *
3808 * - if we'd just tried a public key _offer_,
3809 * the message should be "Server refused our
3810 * key" (or no message at all if the key
3811 * came from Pageant)
3812 *
3813 * - if we'd just tried anything else, the
3814 * message really should be "Access denied".
3815 *
3816 * Additionally, if we'd just tried password
3817 * authentication, we should break out of this
3818 * whole loop so as to go back to the username
3819 * prompt.
3820 */
3821 if (type == AUTH_TYPE_NONE) {
3822 /* do nothing */
3823 } else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
3824 type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
3825 if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
3826 c_write_str("Server refused our key\r\n");
3827 logevent("Server refused public key");
4bdf7c46 3828 } else if (type == AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
3829 /* server declined keyboard-interactive; ignore */
1408a877 3830 } else {
3831 c_write_str("Access denied\r\n");
3832 logevent("Access denied");
3833 if (type == AUTH_TYPE_PASSWORD) {
3834 we_are_in = FALSE;
3835 break;
3836 }
3837 }
3838 } else {
3839 c_write_str("Further authentication required\r\n");
3840 logevent("Further authentication required");
3841 }
65a22376 3842
32874aea 3843 can_pubkey =
3844 in_commasep_string("publickey", methods, methlen);
3845 can_passwd =
3846 in_commasep_string("password", methods, methlen);
761187b6 3847 can_keyb_inter =
3848 in_commasep_string("keyboard-interactive", methods, methlen);
1408a877 3849 }
65a22376 3850
1408a877 3851 method = 0;
65a22376 3852
78afa559 3853 if (!method && can_pubkey && agent_exists() && !tried_agent) {
1983e559 3854 /*
3855 * Attempt public-key authentication using Pageant.
3856 */
3857 static unsigned char request[5], *response, *p;
3858 static int responselen;
3859 static int i, nkeys;
3860 static int authed = FALSE;
3861 void *r;
3862
3863 tried_agent = TRUE;
3864
3865 logevent("Pageant is running. Requesting keys.");
3866
3867 /* Request the keys held by the agent. */
3868 PUT_32BIT(request, 1);
3869 request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
3870 agent_query(request, 5, &r, &responselen);
32874aea 3871 response = (unsigned char *) r;
95797139 3872 if (response && responselen >= 5 &&
32874aea 3873 response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
1983e559 3874 p = response + 5;
32874aea 3875 nkeys = GET_32BIT(p);
3876 p += 4;
3877 {
3878 char buf[64];
3879 sprintf(buf, "Pageant has %d SSH2 keys", nkeys);
3880 logevent(buf);
3881 }
1983e559 3882 for (i = 0; i < nkeys; i++) {
3883 static char *pkblob, *alg, *commentp;
3884 static int pklen, alglen, commentlen;
3885 static int siglen, retlen, len;
3886 static char *q, *agentreq, *ret;
2d466ffd 3887 void *vret;
1983e559 3888
32874aea 3889 {
3890 char buf[64];
3891 sprintf(buf, "Trying Pageant key #%d", i);
3892 logevent(buf);
3893 }
3894 pklen = GET_32BIT(p);
3895 p += 4;
3896 pkblob = p;
3897 p += pklen;
1983e559 3898 alglen = GET_32BIT(pkblob);
3899 alg = pkblob + 4;
32874aea 3900 commentlen = GET_32BIT(p);
3901 p += 4;
3902 commentp = p;
3903 p += commentlen;
1983e559 3904 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3905 ssh2_pkt_addstring(username);
32874aea 3906 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3907 ssh2_pkt_addstring("publickey"); /* method */
3908 ssh2_pkt_addbool(FALSE); /* no signature included */
1983e559 3909 ssh2_pkt_addstring_start();
3910 ssh2_pkt_addstring_data(alg, alglen);
3911 ssh2_pkt_addstring_start();
3912 ssh2_pkt_addstring_data(pkblob, pklen);
3913 ssh2_pkt_send();
3914
3915 crWaitUntilV(ispkt);
3916 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
3917 logevent("Key refused");
3918 continue;
3919 }
3920
32874aea 3921 if (flags & FLAG_VERBOSE) {
3922 c_write_str
3923 ("Authenticating with public key \"");
3924 c_write(commentp, commentlen);
3925 c_write_str("\" from agent\r\n");
3926 }
1983e559 3927
3928 /*
3929 * Server is willing to accept the key.
3930 * Construct a SIGN_REQUEST.
3931 */
3932 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
3933 ssh2_pkt_addstring(username);
32874aea 3934 ssh2_pkt_addstring("ssh-connection"); /* service requested */
3935 ssh2_pkt_addstring("publickey"); /* method */
1983e559 3936 ssh2_pkt_addbool(TRUE);
3937 ssh2_pkt_addstring_start();
3938 ssh2_pkt_addstring_data(alg, alglen);
3939 ssh2_pkt_addstring_start();
3940 ssh2_pkt_addstring_data(pkblob, pklen);
3941
3942 siglen = pktout.length - 5 + 4 + 20;
32874aea 3943 len = 1; /* message type */
3944 len += 4 + pklen; /* key blob */
3945 len += 4 + siglen; /* data to sign */
3946 len += 4; /* flags */
1983e559 3947 agentreq = smalloc(4 + len);
3948 PUT_32BIT(agentreq, len);
3949 q = agentreq + 4;
3950 *q++ = SSH2_AGENTC_SIGN_REQUEST;
32874aea 3951 PUT_32BIT(q, pklen);
3952 q += 4;
3953 memcpy(q, pkblob, pklen);
3954 q += pklen;
3955 PUT_32BIT(q, siglen);
3956 q += 4;
1983e559 3957 /* Now the data to be signed... */
32874aea 3958 PUT_32BIT(q, 20);
3959 q += 4;
3960 memcpy(q, ssh2_session_id, 20);
3961 q += 20;
3962 memcpy(q, pktout.data + 5, pktout.length - 5);
3963 q += pktout.length - 5;
1983e559 3964 /* And finally the (zero) flags word. */
3965 PUT_32BIT(q, 0);
2d466ffd 3966 agent_query(agentreq, len + 4, &vret, &retlen);
3967 ret = vret;
1983e559 3968 sfree(agentreq);
3969 if (ret) {
3970 if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
3971 logevent("Sending Pageant's response");
3972 ssh2_pkt_addstring_start();
32874aea 3973 ssh2_pkt_addstring_data(ret + 9,
3974 GET_32BIT(ret +
3975 5));
1983e559 3976 ssh2_pkt_send();
3977 authed = TRUE;
3978 break;
3979 } else {
32874aea 3980 logevent
3981 ("Pageant failed to answer challenge");
1983e559 3982 sfree(ret);
3983 }
3984 }
3985 }
3986 if (authed)
3987 continue;
3988 }
3989 }
3990
32874aea 3991 if (!method && can_pubkey && *cfg.keyfile
3992 && !tried_pubkey_config) {
1408a877 3993 unsigned char *pub_blob;
3994 char *algorithm, *comment;
3995 int pub_blob_len;
65a22376 3996
1408a877 3997 tried_pubkey_config = TRUE;
65a22376 3998
65a22376 3999 /*
1408a877 4000 * Try the public key supplied in the configuration.
4001 *
4002 * First, offer the public blob to see if the server is
4003 * willing to accept it.
65a22376 4004 */
1408a877 4005 pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
4006 &pub_blob_len);
4007 if (pub_blob) {
4008 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4009 ssh2_pkt_addstring(username);
32874aea 4010 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4011 ssh2_pkt_addstring("publickey"); /* method */
4012 ssh2_pkt_addbool(FALSE); /* no signature included */
1408a877 4013 ssh2_pkt_addstring(algorithm);
4014 ssh2_pkt_addstring_start();
4015 ssh2_pkt_addstring_data(pub_blob, pub_blob_len);
4016 ssh2_pkt_send();
32874aea 4017 logevent("Offered public key"); /* FIXME */
1408a877 4018
4019 crWaitUntilV(ispkt);
4020 if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4021 gotit = TRUE;
4022 type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
32874aea 4023 continue; /* key refused; give up on it */
1408a877 4024 }
65a22376 4025
1408a877 4026 logevent("Offer of public key accepted");
65a22376 4027 /*
1408a877 4028 * Actually attempt a serious authentication using
4029 * the key.
65a22376 4030 */
1408a877 4031 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
32874aea 4032 sprintf(pwprompt,
4033 "Passphrase for key \"%.100s\": ",
4034 comment);
1408a877 4035 need_pw = TRUE;
4036 } else {
4037 need_pw = FALSE;
4038 }
4039 c_write_str("Authenticating with public key \"");
4040 c_write_str(comment);
4041 c_write_str("\"\r\n");
4042 method = AUTH_PUBLICKEY_FILE;
65a22376 4043 }
1408a877 4044 }
4045
af659722 4046 if (!method && can_keyb_inter && !tried_keyb_inter) {
4047 method = AUTH_KEYBOARD_INTERACTIVE;
4048 type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4049 tried_keyb_inter = TRUE;
4050
4051 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4052 ssh2_pkt_addstring(username);
4053 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4054 ssh2_pkt_addstring("keyboard-interactive"); /* method */
4055 ssh2_pkt_addstring(""); /* lang */
4056 ssh2_pkt_addstring("");
4057 ssh2_pkt_send();
4058
4059 crWaitUntilV(ispkt);
4060 if (pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4061 if (pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4062 gotit = TRUE;
4063 logevent("Keyboard-interactive authentication refused");
4064 type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4065 continue;
4066 }
4067
4068 kbd_inter_running = TRUE;
4069 }
4070
4071 if (kbd_inter_running) {
4072 method = AUTH_KEYBOARD_INTERACTIVE;
4073 type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4074 tried_keyb_inter = TRUE;
4075
4076 /* We've got packet with that "interactive" info
4077 dump banners, and set its prompt as ours */
4078 {
4079 char *name, *inst, *lang, *prompt;
4080 int name_len, inst_len, lang_len, prompt_len;
4081 ssh2_pkt_getstring(&name, &name_len);
4082 ssh2_pkt_getstring(&inst, &inst_len);
4083 ssh2_pkt_getstring(&lang, &lang_len);
4084 if (name_len > 0)
4085 c_write_untrusted(name, name_len);
4086 if (inst_len > 0)
4087 c_write_untrusted(inst, inst_len);
4088 num_prompts = ssh2_pkt_getuint32();
4089
4090 ssh2_pkt_getstring(&prompt, &prompt_len);
4091 strncpy(pwprompt, prompt, sizeof(pwprompt));
4092 need_pw = TRUE;
4093
4094 echo = ssh2_pkt_getbool();
4095 }
4096 }
4097
1408a877 4098 if (!method && can_passwd) {
4099 method = AUTH_PASSWORD;
32874aea 4100 sprintf(pwprompt, "%.90s@%.90s's password: ", username,
4101 savedhost);
1408a877 4102 need_pw = TRUE;
4103 }
4104
4105 if (need_pw) {
fa17a66e 4106 if (ssh_get_line) {
4107 if (!ssh_get_line(pwprompt, password,
32874aea 4108 sizeof(password), TRUE)) {
1408a877 4109 /*
fa17a66e 4110 * get_line failed to get a password (for
4111 * example because one was supplied on the
4112 * command line which has already failed to
4113 * work). Terminate.
1408a877 4114 */
2bc6a386 4115 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
4116 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
4117 ssh2_pkt_addstring
4118 ("No more passwords available to try");
4119 ssh2_pkt_addstring("en"); /* language tag */
4120 ssh2_pkt_send();
4121 connection_fatal("Unable to authenticate");
1408a877 4122 ssh_state = SSH_STATE_CLOSED;
4123 crReturnV;
4124 }
4125 } else {
4126 static int pos = 0;
4127 static char c;
4128
761187b6 4129 c_write_untrusted(pwprompt, strlen(pwprompt));
1408a877 4130 ssh_send_ok = 1;
4131
4132 pos = 0;
4133 while (pos >= 0) {
4134 crWaitUntilV(!ispkt);
32874aea 4135 while (inlen--)
4136 switch (c = *in++) {
4137 case 10:
4138 case 13:
4139 password[pos] = 0;
4140 pos = -1;
4141 break;
4142 case 8:
4143 case 127:
4144 if (pos > 0)
4145 pos--;
4146 break;
4147 case 21:
4148 case 27:
4149 pos = 0;
4150 break;
4151 case 3:
4152 case 4:
4153 random_save_seed();
4154 exit(0);
4155 break;
4156 default:
51b2fb65 4157 if (pos < sizeof(password)-1)
32874aea 4158 password[pos++] = c;
4159 break;
4160 }
65a22376 4161 }
1408a877 4162 c_write_str("\r\n");
65a22376 4163 }
65a22376 4164 }
65a22376 4165
1408a877 4166 if (method == AUTH_PUBLICKEY_FILE) {
4167 /*
4168 * We have our passphrase. Now try the actual authentication.
4169 */
4170 struct ssh2_userkey *key;
65a22376 4171
1408a877 4172 key = ssh2_load_userkey(cfg.keyfile, password);
4173 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4174 if (key == SSH2_WRONG_PASSPHRASE) {
4175 c_write_str("Wrong passphrase\r\n");
4176 tried_pubkey_config = FALSE;
4177 } else {
4178 c_write_str("Unable to load private key\r\n");
4179 tried_pubkey_config = TRUE;
4180 }
4181 /* Send a spurious AUTH_NONE to return to the top. */
4182 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4183 ssh2_pkt_addstring(username);
32874aea 4184 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4185 ssh2_pkt_addstring("none"); /* method */
1408a877 4186 ssh2_pkt_send();
4187 type = AUTH_TYPE_NONE;
4188 } else {
4189 unsigned char *blob, *sigdata;
4190 int blob_len, sigdata_len;
65a22376 4191
1408a877 4192 /*
4193 * We have loaded the private key and the server
4194 * has announced that it's willing to accept it.
4195 * Hallelujah. Generate a signature and send it.
4196 */
4197 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4198 ssh2_pkt_addstring(username);
32874aea 4199 ssh2_pkt_addstring("ssh-connection"); /* service requested */
4200 ssh2_pkt_addstring("publickey"); /* method */
1408a877 4201 ssh2_pkt_addbool(TRUE);
4202 ssh2_pkt_addstring(key->alg->name);
4203 blob = key->alg->public_blob(key->data, &blob_len);
4204 ssh2_pkt_addstring_start();
4205 ssh2_pkt_addstring_data(blob, blob_len);
4206 sfree(blob);
4207
4208 /*
4209 * The data to be signed is:
4210 *
4211 * string session-id
4212 *
4213 * followed by everything so far placed in the
4214 * outgoing packet.
4215 */
4216 sigdata_len = pktout.length - 5 + 4 + 20;
4217 sigdata = smalloc(sigdata_len);
4218 PUT_32BIT(sigdata, 20);
32874aea 4219 memcpy(sigdata + 4, ssh2_session_id, 20);
4220 memcpy(sigdata + 24, pktout.data + 5,
4221 pktout.length - 5);
4222 blob =
4223 key->alg->sign(key->data, sigdata, sigdata_len,
4224 &blob_len);
1408a877 4225 ssh2_pkt_addstring_start();
4226 ssh2_pkt_addstring_data(blob, blob_len);
4227 sfree(blob);
4228 sfree(sigdata);
4229
4230 ssh2_pkt_send();
4231 type = AUTH_TYPE_PUBLICKEY;
4232 }
4233 } else if (method == AUTH_PASSWORD) {
65a22376 4234 /*
1408a877 4235 * We send the password packet lumped tightly together with
4236 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4237 * string long enough to make the total length of the two
4238 * packets constant. This should ensure that a passive
4239 * listener doing traffic analyis can't work out the length
4240 * of the password.
4241 *
4242 * For this to work, we need an assumption about the
4243 * maximum length of the password packet. I think 256 is
4244 * pretty conservative. Anyone using a password longer than
4245 * that probably doesn't have much to worry about from
4246 * people who find out how long their password is!
65a22376 4247 */
4248 ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
4249 ssh2_pkt_addstring(username);
32874aea 4250 ssh2_pkt_addstring("ssh-connection"); /* service requested */
1408a877 4251 ssh2_pkt_addstring("password");
4252 ssh2_pkt_addbool(FALSE);
4253 ssh2_pkt_addstring(password);
4254 ssh2_pkt_defer();
65a22376 4255 /*
1408a877 4256 * We'll include a string that's an exact multiple of the
4257 * cipher block size. If the cipher is NULL for some
4258 * reason, we don't do this trick at all because we gain
4259 * nothing by it.
65a22376 4260 */
32874aea 4261 if (cscipher) {
4262 int stringlen, i;
4263
4264 stringlen = (256 - deferred_len);
4265 stringlen += cscipher->blksize - 1;
4266 stringlen -= (stringlen % cscipher->blksize);
4267 if (cscomp) {
4268 /*
4269 * Temporarily disable actual compression,
4270 * so we can guarantee to get this string
4271 * exactly the length we want it. The
4272 * compression-disabling routine should
4273 * return an integer indicating how many
4274 * bytes we should adjust our string length
4275 * by.
4276 */
4277 stringlen -= cscomp->disable_compression();
4278 }
1408a877 4279 ssh2_pkt_init(SSH2_MSG_IGNORE);
4280 ssh2_pkt_addstring_start();
6e9e9520 4281 for (i = 0; i < stringlen; i++) {
32874aea 4282 char c = (char) random_byte();
4283 ssh2_pkt_addstring_data(&c, 1);
65a22376 4284 }
1408a877 4285 ssh2_pkt_defer();
65a22376 4286 }
39065bed 4287 ssh_pkt_defersend();
0d43337a 4288 logevent("Sent password");
1408a877 4289 type = AUTH_TYPE_PASSWORD;
761187b6 4290 } else if (method == AUTH_KEYBOARD_INTERACTIVE) {
4291 ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
4292 ssh2_pkt_adduint32(num_prompts);
4293 ssh2_pkt_addstring(password);
4294 memset(password, 0, sizeof(password));
4295 ssh2_pkt_send();
4296 type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
1408a877 4297 } else {
32874aea 4298 c_write_str
4299 ("No supported authentication methods left to try!\r\n");
4300 logevent
4301 ("No supported authentications offered. Disconnecting");
1408a877 4302 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
4303 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
32874aea 4304 ssh2_pkt_addstring
4305 ("No supported authentication methods available");
4306 ssh2_pkt_addstring("en"); /* language tag */
1408a877 4307 ssh2_pkt_send();
4308 ssh_state = SSH_STATE_CLOSED;
4309 crReturnV;
65a22376 4310 }
65a22376 4311 }
1408a877 4312 } while (!we_are_in);
7cca0d81 4313
4314 /*
4315 * Now we're authenticated for the connection protocol. The
4316 * connection protocol will automatically have started at this
4317 * point; there's no need to send SERVICE_REQUEST.
4318 */
4319
4320 /*
4321 * So now create a channel with a session in it.
4322 */
d2371c81 4323 ssh_channels = newtree234(ssh_channelcmp);
dcbde236 4324 mainchan = smalloc(sizeof(struct ssh_channel));
d2371c81 4325 mainchan->localid = alloc_channel_id();
7cca0d81 4326 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
4327 ssh2_pkt_addstring("session");
d211621f 4328 ssh2_pkt_adduint32(mainchan->localid);
5471d09a 4329 mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
4330 ssh2_pkt_adduint32(mainchan->v.v2.locwindow); /* our window size */
32874aea 4331 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
7cca0d81 4332 ssh2_pkt_send();
4333 crWaitUntilV(ispkt);
4334 if (pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
32874aea 4335 bombout(("Server refused to open a session"));
4336 crReturnV;
4337 /* FIXME: error data comes back in FAILURE packet */
7cca0d81 4338 }
d211621f 4339 if (ssh2_pkt_getuint32() != mainchan->localid) {
32874aea 4340 bombout(("Server's channel confirmation cited wrong channel"));
4341 crReturnV;
7cca0d81 4342 }
d211621f 4343 mainchan->remoteid = ssh2_pkt_getuint32();
783415f8 4344 mainchan->type = CHAN_MAINSESSION;
4345 mainchan->closes = 0;
5471d09a 4346 mainchan->v.v2.remwindow = ssh2_pkt_getuint32();
4347 mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32();
4348 bufchain_init(&mainchan->v.v2.outbuffer);
783415f8 4349 add234(ssh_channels, mainchan);
7cca0d81 4350 logevent("Opened channel for session");
4351
4352 /*
783415f8 4353 * Potentially enable X11 forwarding.
4354 */
4355 if (cfg.x11_forward) {
32874aea 4356 char proto[20], data[64];
4357 logevent("Requesting X11 forwarding");
4358 x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
4359 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4360 ssh2_pkt_adduint32(mainchan->remoteid);
4361 ssh2_pkt_addstring("x11-req");
4362 ssh2_pkt_addbool(1); /* want reply */
4363 ssh2_pkt_addbool(0); /* many connections */
4364 ssh2_pkt_addstring(proto);
4365 ssh2_pkt_addstring(data);
4366 ssh2_pkt_adduint32(0); /* screen number */
4367 ssh2_pkt_send();
4368
4369 do {
4370 crWaitUntilV(ispkt);
4371 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
4372 unsigned i = ssh2_pkt_getuint32();
4373 struct ssh_channel *c;
4374 c = find234(ssh_channels, &i, ssh_channelfind);
4375 if (!c)
4376 continue; /* nonexistent channel */
5471d09a 4377 c->v.v2.remwindow += ssh2_pkt_getuint32();
32874aea 4378 }
4379 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4380
4381 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
4382 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
4383 bombout(("Server got confused by X11 forwarding request"));
4384 crReturnV;
4385 }
4386 logevent("X11 forwarding refused");
4387 } else {
4388 logevent("X11 forwarding enabled");
783415f8 4389 ssh_X11_fwd_enabled = TRUE;
32874aea 4390 }
783415f8 4391 }
4392
4393 /*
bc240b21 4394 * Enable port forwardings.
4395 */
4396 {
4397 static char *e; /* preserve across crReturn */
4398 char type;
4399 int n;
4400 int sport,dport;
4401 char sports[256], dports[256], host[256];
4402 char buf[1024];
4403
4404 ssh_rportfwds = newtree234(ssh_rportcmp_ssh2);
4405 /* Add port forwardings. */
4406 e = cfg.portfwd;
4407 while (*e) {
4408 type = *e++;
4409 n = 0;
4410 while (*e && *e != '\t')
4411 sports[n++] = *e++;
4412 sports[n] = 0;
4413 if (*e == '\t')
4414 e++;
4415 n = 0;
4416 while (*e && *e != ':')
4417 host[n++] = *e++;
4418 host[n] = 0;
4419 if (*e == ':')
4420 e++;
4421 n = 0;
4422 while (*e)
4423 dports[n++] = *e++;
4424 dports[n] = 0;
4425 e++;
4426 dport = atoi(dports);
4427 sport = atoi(sports);
4428 if (sport && dport) {
4429 if (type == 'L') {
4430 pfd_addforward(host, dport, sport);
4431 sprintf(buf, "Local port %d forwarding to %s:%d",
4432 sport, host, dport);
4433 logevent(buf);
4434 } else {
4435 struct ssh_rportfwd *pf;
4436 pf = smalloc(sizeof(*pf));
4437 strcpy(pf->dhost, host);
4438 pf->dport = dport;
4439 pf->sport = sport;
4440 if (add234(ssh_rportfwds, pf) != pf) {
4441 sprintf(buf,
95bc8819 4442 "Duplicate remote port forwarding to %s:%d",
bc240b21 4443 host, dport);
4444 logevent(buf);
4445 sfree(pf);
4446 } else {
4447 sprintf(buf, "Requesting remote port %d (forwarded to %s:%d)",
4448 sport, host, dport);
4449 logevent(buf);
4450 ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
4451 ssh2_pkt_addstring("tcpip-forward");
4452 ssh2_pkt_addbool(1);/* want reply */
4453 ssh2_pkt_addstring("127.0.0.1");
4454 ssh2_pkt_adduint32(sport);
4455 ssh2_pkt_send();
4456
4457 do {
4458 crWaitUntilV(ispkt);
4459 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
4460 unsigned i = ssh2_pkt_getuint32();
4461 struct ssh_channel *c;
4462 c = find234(ssh_channels, &i, ssh_channelfind);
4463 if (!c)
4464 continue;/* nonexistent channel */
5471d09a 4465 c->v.v2.remwindow += ssh2_pkt_getuint32();
bc240b21 4466 }
4467 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4468
4469 if (pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
4470 if (pktin.type != SSH2_MSG_REQUEST_FAILURE) {
4471 bombout(("Server got confused by port forwarding request"));
4472 crReturnV;
4473 }
4474 logevent("Server refused this port forwarding");
4475 } else {
4476 logevent("Remote port forwarding enabled");
4477 }
4478 }
4479 }
4480 }
4481 }
4482 }
4483
4484 /*
36c2a3e9 4485 * Potentially enable agent forwarding.
4486 */
4487 if (cfg.agentfwd && agent_exists()) {
32874aea 4488 logevent("Requesting OpenSSH-style agent forwarding");
4489 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4490 ssh2_pkt_adduint32(mainchan->remoteid);
4491 ssh2_pkt_addstring("auth-agent-req@openssh.com");
4492 ssh2_pkt_addbool(1); /* want reply */
4493 ssh2_pkt_send();
4494
4495 do {
4496 crWaitUntilV(ispkt);
4497 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
4498 unsigned i = ssh2_pkt_getuint32();
4499 struct ssh_channel *c;
4500 c = find234(ssh_channels, &i, ssh_channelfind);
4501 if (!c)
4502 continue; /* nonexistent channel */
5471d09a 4503 c->v.v2.remwindow += ssh2_pkt_getuint32();
32874aea 4504 }
4505 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4506
4507 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
4508 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
4509 bombout(
4510 ("Server got confused by agent forwarding request"));
4511 crReturnV;
4512 }
4513 logevent("Agent forwarding refused");
4514 } else {
4515 logevent("Agent forwarding enabled");
36c2a3e9 4516 ssh_agentfwd_enabled = TRUE;
32874aea 4517 }
36c2a3e9 4518 }
4519
4520 /*
7cca0d81 4521 * Now allocate a pty for the session.
4522 */
67779be7 4523 if (!cfg.nopty) {
32874aea 4524 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4525 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
4526 ssh2_pkt_addstring("pty-req");
4527 ssh2_pkt_addbool(1); /* want reply */
4528 ssh2_pkt_addstring(cfg.termtype);
4529 ssh2_pkt_adduint32(cols);
4530 ssh2_pkt_adduint32(rows);
4531 ssh2_pkt_adduint32(0); /* pixel width */
4532 ssh2_pkt_adduint32(0); /* pixel height */
4533 ssh2_pkt_addstring_start();
4534 ssh2_pkt_addstring_data("\0", 1); /* TTY_OP_END, no special options */
4535 ssh2_pkt_send();
4536 ssh_state = SSH_STATE_INTERMED;
4537
4538 do {
4539 crWaitUntilV(ispkt);
4540 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
4541 unsigned i = ssh2_pkt_getuint32();
4542 struct ssh_channel *c;
4543 c = find234(ssh_channels, &i, ssh_channelfind);
4544 if (!c)
4545 continue; /* nonexistent channel */
5471d09a 4546 c->v.v2.remwindow += ssh2_pkt_getuint32();
32874aea 4547 }
4548 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4549
4550 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
4551 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
4552 bombout(("Server got confused by pty request"));
4553 crReturnV;
4554 }
4555 c_write_str("Server refused to allocate pty\r\n");
4556 ssh_editing = ssh_echoing = 1;
4557 } else {
4558 logevent("Allocated pty");
4559 }
0965bee0 4560 } else {
32874aea 4561 ssh_editing = ssh_echoing = 1;
7cca0d81 4562 }
4563
4564 /*
fd5e5847 4565 * Start a shell or a remote command. We may have to attempt
4566 * this twice if the config data has provided a second choice
4567 * of command.
7cca0d81 4568 */
fd5e5847 4569 while (1) {
4570 int subsys;
4571 char *cmd;
4572
4573 if (ssh_fallback_cmd) {
4574 subsys = cfg.ssh_subsys2;
4575 cmd = cfg.remote_cmd_ptr2;
4576 } else {
4577 subsys = cfg.ssh_subsys;
4578 cmd = cfg.remote_cmd_ptr;
4579 }
4580
4581 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
4582 ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
4583 if (subsys) {
4584 ssh2_pkt_addstring("subsystem");
4585 ssh2_pkt_addbool(1); /* want reply */
4586 ssh2_pkt_addstring(cmd);
4587 } else if (*cmd) {
4588 ssh2_pkt_addstring("exec");
4589 ssh2_pkt_addbool(1); /* want reply */
4590 ssh2_pkt_addstring(cmd);
4591 } else {
4592 ssh2_pkt_addstring("shell");
4593 ssh2_pkt_addbool(1); /* want reply */
32874aea 4594 }
fd5e5847 4595 ssh2_pkt_send();
4596 do {
4597 crWaitUntilV(ispkt);
4598 if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
4599 unsigned i = ssh2_pkt_getuint32();
4600 struct ssh_channel *c;
4601 c = find234(ssh_channels, &i, ssh_channelfind);
4602 if (!c)
4603 continue; /* nonexistent channel */
4604 c->v.v2.remwindow += ssh2_pkt_getuint32();
4605 }
4606 } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4607 if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
4608 if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
4609 bombout(("Server got confused by shell/command request"));
4610 crReturnV;
4611 }
4612 /*
4613 * We failed to start the command. If this is the
4614 * fallback command, we really are finished; if it's
4615 * not, and if the fallback command exists, try falling
4616 * back to it before complaining.
4617 */
4618 if (!ssh_fallback_cmd && cfg.remote_cmd_ptr2 != NULL) {
4619 logevent("Primary command failed; attempting fallback");
4620 ssh_fallback_cmd = TRUE;
4621 continue;
4622 }
4623 bombout(("Server refused to start a shell/command"));
32874aea 4624 crReturnV;
fd5e5847 4625 } else {
4626 logevent("Started a shell/command");
32874aea 4627 }
fd5e5847 4628 break;
7cca0d81 4629 }
4630
6e48c3fe 4631 ssh_state = SSH_STATE_SESSION;
4632 if (size_needed)
4633 ssh_size();
3687d221 4634 if (eof_needed)
32874aea 4635 ssh_special(TS_EOF);
6e48c3fe 4636
7cca0d81 4637 /*
4638 * Transfer data!
4639 */
32874aea 4640 ldisc_send(NULL, 0); /* cause ldisc to notice changes */
8ccc75b0 4641 ssh_send_ok = 1;
7cca0d81 4642 while (1) {
32874aea 4643 static int try_send;
e5574168 4644 crReturnV;
32874aea 4645 try_send = FALSE;
7cca0d81 4646 if (ispkt) {
4647 if (pktin.type == SSH2_MSG_CHANNEL_DATA ||
32874aea 4648 pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
4649 char *data;
4650 int length;
4651 unsigned i = ssh2_pkt_getuint32();
4652 struct ssh_channel *c;
4653 c = find234(ssh_channels, &i, ssh_channelfind);
4654 if (!c)
4655 continue; /* nonexistent channel */
4656 if (pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
4657 ssh2_pkt_getuint32() != SSH2_EXTENDED_DATA_STDERR)
4658 continue; /* extended but not stderr */
4659 ssh2_pkt_getstring(&data, &length);
4660 if (data) {
5471d09a 4661 int bufsize;
4662 c->v.v2.locwindow -= length;
32874aea 4663 switch (c->type) {
4664 case CHAN_MAINSESSION:
5471d09a 4665 bufsize =
4666 from_backend(pktin.type ==
4667 SSH2_MSG_CHANNEL_EXTENDED_DATA,
4668 data, length);
32874aea 4669 break;
4670 case CHAN_X11:
5471d09a 4671 bufsize = x11_send(c->u.x11.s, data, length);
32874aea 4672 break;
d74d141c 4673 case CHAN_SOCKDATA:
5471d09a 4674 bufsize = pfd_send(c->u.pfd.s, data, length);
bc240b21 4675 break;
36c2a3e9 4676 case CHAN_AGENT:
32874aea 4677 while (length > 0) {
4678 if (c->u.a.lensofar < 4) {
4679 int l = min(4 - c->u.a.lensofar, length);
4680 memcpy(c->u.a.msglen + c->u.a.lensofar,
4681 data, l);
4682 data += l;
4683 length -= l;
4684 c->u.a.lensofar += l;
4685 }
4686 if (c->u.a.lensofar == 4) {
4687 c->u.a.totallen =
4688 4 + GET_32BIT(c->u.a.msglen);
4689 c->u.a.message = smalloc(c->u.a.totallen);
4690 memcpy(c->u.a.message, c->u.a.msglen, 4);
4691 }
4692 if (c->u.a.lensofar >= 4 && length > 0) {
4693 int l =
4694 min(c->u.a.totallen - c->u.a.lensofar,
4695 length);
4696 memcpy(c->u.a.message + c->u.a.lensofar,
4697 data, l);
4698 data += l;
4699 length -= l;
4700 c->u.a.lensofar += l;
4701 }
4702 if (c->u.a.lensofar == c->u.a.totallen) {
4703 void *reply, *sentreply;
4704 int replylen;
4705 agent_query(c->u.a.message,
4706 c->u.a.totallen, &reply,
4707 &replylen);
4708 if (reply)
4709 sentreply = reply;
4710 else {
4711 /* Fake SSH_AGENT_FAILURE. */
4712 sentreply = "\0\0\0\1\5";
4713 replylen = 5;
4714 }
4715 ssh2_add_channel_data(c, sentreply,
4716 replylen);
36c2a3e9 4717 try_send = TRUE;
32874aea 4718 if (reply)
4719 sfree(reply);
4720 sfree(c->u.a.message);
4721 c->u.a.lensofar = 0;
4722 }
4723 }
5471d09a 4724 bufsize = 0;
32874aea 4725 break;
4726 }
4727 /*
5471d09a 4728 * If we are not buffering too much data,
4729 * enlarge the window again at the remote side.
32874aea 4730 */
5471d09a 4731 if (bufsize < OUR_V2_WINSIZE)
4732 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
32874aea 4733 }
7cca0d81 4734 } else if (pktin.type == SSH2_MSG_DISCONNECT) {
32874aea 4735 ssh_state = SSH_STATE_CLOSED;
d211621f 4736 logevent("Received disconnect message");
32874aea 4737 crReturnV;
7cca0d81 4738 } else if (pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
32874aea 4739 continue; /* exit status et al; ignore (FIXME?) */
d211621f 4740 } else if (pktin.type == SSH2_MSG_CHANNEL_EOF) {
32874aea 4741 unsigned i = ssh2_pkt_getuint32();
4742 struct ssh_channel *c;
4743
4744 c = find234(ssh_channels, &i, ssh_channelfind);
4745 if (!c)
4746 continue; /* nonexistent channel */
4747
4748 if (c->type == CHAN_X11) {
4749 /*
4750 * Remote EOF on an X11 channel means we should
4751 * wrap up and close the channel ourselves.
4752 */
4753 x11_close(c->u.x11.s);
4754 sshfwd_close(c);
4755 } else if (c->type == CHAN_AGENT) {
36c2a3e9 4756 sshfwd_close(c);
d74d141c 4757 } else if (c->type == CHAN_SOCKDATA) {
bc240b21 4758 pfd_close(c->u.pfd.s);
4759 sshfwd_close(c);
36c2a3e9 4760 }
d211621f 4761 } else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
32874aea 4762 unsigned i = ssh2_pkt_getuint32();
4763 struct ssh_channel *c;
4764
4765 c = find234(ssh_channels, &i, ssh_channelfind);
4766 if (!c)
4767 continue; /* nonexistent channel */
32874aea 4768 /* Do pre-close processing on the channel. */
4769 switch (c->type) {
4770 case CHAN_MAINSESSION:
4771 break; /* nothing to see here, move along */
4772 case CHAN_X11:
92f157bd 4773 if (c->u.x11.s != NULL)
4774 x11_close(c->u.x11.s);
4775 sshfwd_close(c);
32874aea 4776 break;
4777 case CHAN_AGENT:
92f157bd 4778 sshfwd_close(c);
32874aea 4779 break;
d74d141c 4780 case CHAN_SOCKDATA:
92f157bd 4781 if (c->u.pfd.s != NULL)
4782 pfd_close(c->u.pfd.s);
4783 sshfwd_close(c);
bc240b21 4784 break;
32874aea 4785 }
92f157bd 4786 if (c->closes == 0) {
4787 ssh2_pkt_init(SSH2_MSG_CHANNEL_CLOSE);
4788 ssh2_pkt_adduint32(c->remoteid);
4789 ssh2_pkt_send();
4790 }
32874aea 4791 del234(ssh_channels, c);
5471d09a 4792 bufchain_clear(&c->v.v2.outbuffer);
32874aea 4793 sfree(c);
4794
4795 /*
4796 * See if that was the last channel left open.
4797 */
4798 if (count234(ssh_channels) == 0) {
4799 logevent("All channels closed. Disconnecting");
4800 ssh2_pkt_init(SSH2_MSG_DISCONNECT);
4801 ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
4802 ssh2_pkt_addstring("All open channels closed");
4803 ssh2_pkt_addstring("en"); /* language tag */
4804 ssh2_pkt_send();
4805 ssh_state = SSH_STATE_CLOSED;
4806 crReturnV;
4807 }
4808 continue; /* remote sends close; ignore (FIXME) */
7cca0d81 4809 } else if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
32874aea 4810 unsigned i = ssh2_pkt_getuint32();
4811 struct ssh_channel *c;
4812 c = find234(ssh_channels, &i, ssh_channelfind);
4813 if (!c)
4814 continue; /* nonexistent channel */
5471d09a 4815 c->v.v2.remwindow += ssh2_pkt_getuint32();
32874aea 4816 try_send = TRUE;
bc240b21 4817 } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
4818 unsigned i = ssh2_pkt_getuint32();
4819 struct ssh_channel *c;
4820 c = find234(ssh_channels, &i, ssh_channelfind);
4821 if (!c)
4822 continue; /* nonexistent channel */
4823 if (c->type != CHAN_SOCKDATA_DORMANT)
4824 continue; /* dunno why they're confirming this */
4825 c->remoteid = ssh2_pkt_getuint32();
4826 c->type = CHAN_SOCKDATA;
4827 c->closes = 0;
5471d09a 4828 c->v.v2.remwindow = ssh2_pkt_getuint32();
4829 c->v.v2.remmaxpkt = ssh2_pkt_getuint32();
4830 bufchain_init(&c->v.v2.outbuffer);
bc240b21 4831 pfd_confirm(c->u.pfd.s);
724cface 4832 } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
4833 unsigned i = ssh2_pkt_getuint32();
4834 struct ssh_channel *c;
4835 c = find234(ssh_channels, &i, ssh_channelfind);
4836 if (!c)
4837 continue; /* nonexistent channel */
4838 if (c->type != CHAN_SOCKDATA_DORMANT)
4839 continue; /* dunno why they're failing this */
4840
4841 logevent("Forwarded connection refused by server");
4842
4843 pfd_close(c->u.pfd.s);
4844
4845 del234(ssh_channels, c);
4846 sfree(c);
783415f8 4847 } else if (pktin.type == SSH2_MSG_CHANNEL_OPEN) {
32874aea 4848 char *type;
4849 int typelen;
4850 char *error = NULL;
4851 struct ssh_channel *c;
bc240b21 4852 unsigned remid, winsize, pktsize;
32874aea 4853 ssh2_pkt_getstring(&type, &typelen);
4854 c = smalloc(sizeof(struct ssh_channel));
4855
bc240b21 4856 remid = ssh2_pkt_getuint32();
4857 winsize = ssh2_pkt_getuint32();
4858 pktsize = ssh2_pkt_getuint32();
4859
32874aea 4860 if (typelen == 3 && !memcmp(type, "x11", 3)) {
4861 if (!ssh_X11_fwd_enabled)
4862 error = "X11 forwarding is not enabled";
4863 else if (x11_init(&c->u.x11.s, cfg.x11_display, c) !=
4864 NULL) {
4865 error = "Unable to open an X11 connection";
4866 } else {
4867 c->type = CHAN_X11;
4868 }
bc240b21 4869 } else if (typelen == 15 &&
4870 !memcmp(type, "forwarded-tcpip", 15)) {
4871 struct ssh_rportfwd pf, *realpf;
4872 char *dummy;
4873 int dummylen;
4874 ssh2_pkt_getstring(&dummy, &dummylen);/* skip address */
4875 pf.sport = ssh2_pkt_getuint32();
4876 realpf = find234(ssh_rportfwds, &pf, NULL);
4877 if (realpf == NULL) {
4878 error = "Remote port is not recognised";
4879 } else {
4880 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
4881 realpf->dport, c);
4882 char buf[1024];
4883 sprintf(buf, "Received remote port open request for %s:%d",
4884 realpf->dhost, realpf->dport);
4885 logevent(buf);
4886 if (e != NULL) {
4887 sprintf(buf, "Port open failed: %s", e);
4888 logevent(buf);
4889 error = "Port open failed";
4890 } else {
4891 logevent("Forwarded port opened successfully");
4892 c->type = CHAN_SOCKDATA;
4893 }
4894 }
32874aea 4895 } else if (typelen == 22 &&
36c2a3e9 4896 !memcmp(type, "auth-agent@openssh.com", 3)) {
32874aea 4897 if (!ssh_agentfwd_enabled)
4898 error = "Agent forwarding is not enabled";
36c2a3e9 4899 else {
32874aea 4900 c->type = CHAN_AGENT; /* identify channel type */
36c2a3e9 4901 c->u.a.lensofar = 0;
32874aea 4902 }
4903 } else {
4904 error = "Unsupported channel type requested";
4905 }
4906
bc240b21 4907 c->remoteid = remid;
32874aea 4908 if (error) {
4909 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_FAILURE);
4910 ssh2_pkt_adduint32(c->remoteid);
4911 ssh2_pkt_adduint32(SSH2_OPEN_CONNECT_FAILED);
4912 ssh2_pkt_addstring(error);
4913 ssh2_pkt_addstring("en"); /* language tag */
4914 ssh2_pkt_send();
4915 sfree(c);
4916 } else {
4917 c->localid = alloc_channel_id();
4918 c->closes = 0;
5471d09a 4919 c->v.v2.locwindow = OUR_V2_WINSIZE;
4920 c->v.v2.remwindow = winsize;
4921 c->v.v2.remmaxpkt = pktsize;
4922 bufchain_init(&c->v.v2.outbuffer);
32874aea 4923 add234(ssh_channels, c);
4924 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
4925 ssh2_pkt_adduint32(c->remoteid);
4926 ssh2_pkt_adduint32(c->localid);
5471d09a 4927 ssh2_pkt_adduint32(c->v.v2.locwindow);
32874aea 4928 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
4929 ssh2_pkt_send();
4930 }
7cca0d81 4931 } else {
8d5de777 4932 bombout(("Strange packet received: type %d", pktin.type));
32874aea 4933 crReturnV;
7cca0d81 4934 }
4935 } else {
32874aea 4936 /*
4937 * We have spare data. Add it to the channel buffer.
4938 */
4939 ssh2_add_channel_data(mainchan, in, inlen);
4940 try_send = TRUE;
4941 }
4942 if (try_send) {
4943 int i;
4944 struct ssh_channel *c;
4945 /*
4946 * Try to send data on all channels if we can.
4947 */
5471d09a 4948 for (i = 0; NULL != (c = index234(ssh_channels, i)); i++) {
4949 int bufsize = ssh2_try_send(c);
4950 if (bufsize == 0) {
4951 switch (c->type) {
4952 case CHAN_MAINSESSION:
4953 /* stdin need not receive an unthrottle
4954 * notification since it will be polled */
4955 break;
4956 case CHAN_X11:
4957 x11_unthrottle(c->u.x11.s);
4958 break;
4959 case CHAN_AGENT:
4960 /* agent sockets are request/response and need no
4961 * buffer management */
4962 break;
4963 case CHAN_SOCKDATA:
4964 pfd_unthrottle(c->u.pfd.s);
4965 break;
4966 }
4967 }
4968 }
7cca0d81 4969 }
e5574168 4970 }
4971
4972 crFinishV;
4973}
4974
4975/*
7cca0d81 4976 * Handle the top-level SSH2 protocol.
4977 */
4978static void ssh2_protocol(unsigned char *in, int inlen, int ispkt)
4979{
4980 if (do_ssh2_transport(in, inlen, ispkt) == 0)
32874aea 4981 return;
7cca0d81 4982 do_ssh2_authconn(in, inlen, ispkt);
4983}
4984
4985/*
8df7a775 4986 * Called to set up the connection.
374330e2 4987 *
4988 * Returns an error message, or NULL on success.
374330e2 4989 */
32874aea 4990static char *ssh_init(char *host, int port, char **realhost)
4991{
fb09bf1c 4992 char *p;
32874aea 4993
8f203108 4994#ifdef MSCRYPTOAPI
32874aea 4995 if (crypto_startup() == 0)
8f203108 4996 return "Microsoft high encryption pack not installed!";
4997#endif
374330e2 4998
8df7a775 4999 ssh_send_ok = 0;
0965bee0 5000 ssh_editing = 0;
5001 ssh_echoing = 0;
5471d09a 5002 ssh1_throttle_count = 0;
5003 ssh_overall_bufsize = 0;
fd5e5847 5004 ssh_fallback_cmd = 0;
8df7a775 5005
fb09bf1c 5006 p = connect_to_host(host, port, realhost);
5007 if (p != NULL)
5008 return p;
374330e2 5009
374330e2 5010 return NULL;
5011}
5012
5013/*
374330e2 5014 * Called to send data down the Telnet connection.
5015 */
5471d09a 5016static int ssh_send(char *buf, int len)
32874aea 5017{
f78051a1 5018 if (s == NULL || ssh_protocol == NULL)
5471d09a 5019 return 0;
374330e2 5020
5021 ssh_protocol(buf, len, 0);
5471d09a 5022
5023 return ssh_sendbuffer();
5024}
5025
5026/*
5027 * Called to query the current amount of buffered stdin data.
5028 */
5029static int ssh_sendbuffer(void)
5030{
5031 int override_value;
5032
5033 if (s == NULL || ssh_protocol == NULL)
5034 return 0;
5035
5036 /*
5037 * If the SSH socket itself has backed up, add the total backup
5038 * size on that to any individual buffer on the stdin channel.
5039 */
5040 override_value = 0;
5041 if (ssh_throttled_all)
5042 override_value = ssh_overall_bufsize;
5043
5044 if (ssh_version == 1) {
5045 return override_value;
5046 } else if (ssh_version == 2) {
5047 if (!mainchan || mainchan->closes > 0)
5048 return override_value;
5049 else
5050 return override_value + bufchain_size(&mainchan->v.v2.outbuffer);
5051 }
5052
5053 return 0;
374330e2 5054}
5055
5056/*
6e48c3fe 5057 * Called to set the size of the window from SSH's POV.
374330e2 5058 */
32874aea 5059static void ssh_size(void)
5060{
374330e2 5061 switch (ssh_state) {
5062 case SSH_STATE_BEFORE_SIZE:
3687d221 5063 case SSH_STATE_PREPACKET:
21248260 5064 case SSH_STATE_CLOSED:
374330e2 5065 break; /* do nothing */
5066 case SSH_STATE_INTERMED:
5067 size_needed = TRUE; /* buffer for later */
5068 break;
5069 case SSH_STATE_SESSION:
32874aea 5070 if (!cfg.nopty) {
5071 if (ssh_version == 1) {
5072 send_packet(SSH1_CMSG_WINDOW_SIZE,
5073 PKT_INT, rows, PKT_INT, cols,
5074 PKT_INT, 0, PKT_INT, 0, PKT_END);
5075 } else {
5076 ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
5077 ssh2_pkt_adduint32(mainchan->remoteid);
5078 ssh2_pkt_addstring("window-change");
5079 ssh2_pkt_addbool(0);
5080 ssh2_pkt_adduint32(cols);
5081 ssh2_pkt_adduint32(rows);
5082 ssh2_pkt_adduint32(0);
5083 ssh2_pkt_adduint32(0);
5084 ssh2_pkt_send();
5085 }
5086 }
5087 break;
374330e2 5088 }
5089}
5090
5091/*
6abbf9e3 5092 * Send Telnet special codes. TS_EOF is useful for `plink', so you
5093 * can send an EOF and collect resulting output (e.g. `plink
5094 * hostname sort').
374330e2 5095 */
32874aea 5096static void ssh_special(Telnet_Special code)
5097{
6abbf9e3 5098 if (code == TS_EOF) {
32874aea 5099 if (ssh_state != SSH_STATE_SESSION) {
5100 /*
5101 * Buffer the EOF in case we are pre-SESSION, so we can
5102 * send it as soon as we reach SESSION.
5103 */
5104 if (code == TS_EOF)
5105 eof_needed = TRUE;
5106 return;
5107 }
5108 if (ssh_version == 1) {
5109 send_packet(SSH1_CMSG_EOF, PKT_END);
5110 } else {
5111 ssh2_pkt_init(SSH2_MSG_CHANNEL_EOF);
5112 ssh2_pkt_adduint32(mainchan->remoteid);
5113 ssh2_pkt_send();
5114 }
5115 logevent("Sent EOF message");
ec55b220 5116 } else if (code == TS_PING) {
32874aea 5117 if (ssh_state == SSH_STATE_CLOSED
5118 || ssh_state == SSH_STATE_PREPACKET) return;
5119 if (ssh_version == 1) {
5120 send_packet(SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
5121 } else {
5122 ssh2_pkt_init(SSH2_MSG_IGNORE);
5123 ssh2_pkt_addstring_start();
5124 ssh2_pkt_send();
5125 }
6abbf9e3 5126 } else {
32874aea 5127 /* do nothing */
6abbf9e3 5128 }
374330e2 5129}
5130
d74d141c 5131void *new_sock_channel(Socket s)
5132{
5133 struct ssh_channel *c;
5134 c = smalloc(sizeof(struct ssh_channel));
5135
5136 if (c) {
bc240b21 5137 c->remoteid = -1; /* to be set when open confirmed */
d74d141c 5138 c->localid = alloc_channel_id();
5139 c->closes = 0;
bc240b21 5140 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
d74d141c 5141 c->u.pfd.s = s;
5142 add234(ssh_channels, c);
5143 }
5144 return c;
5145}
5146
5471d09a 5147/*
5148 * This is called when stdout/stderr (the entity to which
5149 * from_backend sends data) manages to clear some backlog.
5150 */
5151void ssh_unthrottle(int bufsize)
5152{
5153 if (ssh_version == 1) {
90347b95 5154 if (ssh1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
5471d09a 5155 ssh1_stdout_throttling = 0;
5156 ssh1_throttle(-1);
5157 }
5158 } else {
5159 if (mainchan && mainchan->closes == 0)
5160 ssh2_set_window(mainchan, OUR_V2_WINSIZE - bufsize);
5161 }
5162}
5163
d74d141c 5164void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
5165{
5166 struct ssh_channel *c = (struct ssh_channel *)channel;
5167 char buf[1024];
5168
5169 sprintf(buf, "Opening forwarded connection to %.512s:%d", hostname, port);
5170 logevent(buf);
5171
bc240b21 5172 if (ssh_version == 1) {
5173 send_packet(SSH1_MSG_PORT_OPEN,
5174 PKT_INT, c->localid,
5175 PKT_STR, hostname,
5176 PKT_INT, port,
5177 //PKT_STR, <org:orgport>,
5178 PKT_END);
5179 } else {
5180 ssh2_pkt_init(SSH2_MSG_CHANNEL_OPEN);
5181 ssh2_pkt_addstring("direct-tcpip");
5182 ssh2_pkt_adduint32(c->localid);
5471d09a 5183 c->v.v2.locwindow = OUR_V2_WINSIZE;
5184 ssh2_pkt_adduint32(c->v.v2.locwindow);/* our window size */
bc240b21 5185 ssh2_pkt_adduint32(0x4000UL); /* our max pkt size */
5186 ssh2_pkt_addstring(hostname);
5187 ssh2_pkt_adduint32(port);
5188 /*
5189 * We make up values for the originator data; partly it's
5190 * too much hassle to keep track, and partly I'm not
5191 * convinced the server should be told details like that
5192 * about my local network configuration.
5193 */
5194 ssh2_pkt_addstring("client-side-connection");
5195 ssh2_pkt_adduint32(0);
5196 ssh2_pkt_send();
5197 }
d74d141c 5198}
5199
5200
32874aea 5201static Socket ssh_socket(void)
5202{
5203 return s;
5204}
8ccc75b0 5205
32874aea 5206static int ssh_sendok(void)
5207{
5208 return ssh_send_ok;
5209}
fb09bf1c 5210
32874aea 5211static int ssh_ldisc(int option)
5212{
5213 if (option == LD_ECHO)
5214 return ssh_echoing;
5215 if (option == LD_EDIT)
5216 return ssh_editing;
0965bee0 5217 return FALSE;
5218}
5219
374330e2 5220Backend ssh_backend = {
5221 ssh_init,
374330e2 5222 ssh_send,
5471d09a 5223 ssh_sendbuffer,
374330e2 5224 ssh_size,
4017be6d 5225 ssh_special,
8ccc75b0 5226 ssh_socket,
97db3be4 5227 ssh_sendok,
0965bee0 5228 ssh_ldisc,
5471d09a 5229 ssh_unthrottle,
97db3be4 5230 22
bc240b21 5231};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator