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Implement access to the SSH agent. This ought to make agent
[u/mdw/putty] / ssh.c
CommitLineData
374330e2 1#include <stdio.h>
2#include <stdlib.h>
fb09bf1c 3#include <stdarg.h>
4#include <assert.h>
374330e2 5
6#include "putty.h"
dacbd0e8 7#include "tree234.h"
fb09bf1c 8#include "ssh.h"
374330e2 9
10#ifndef FALSE
11#define FALSE 0
12#endif
13#ifndef TRUE
14#define TRUE 1
15#endif
16
32874aea 17#define SSH1_MSG_DISCONNECT 1 /* 0x1 */
18#define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
19#define SSH1_CMSG_SESSION_KEY 3 /* 0x3 */
20#define SSH1_CMSG_USER 4 /* 0x4 */
21#define SSH1_CMSG_AUTH_RSA 6 /* 0x6 */
22#define SSH1_SMSG_AUTH_RSA_CHALLENGE 7 /* 0x7 */
23#define SSH1_CMSG_AUTH_RSA_RESPONSE 8 /* 0x8 */
24#define SSH1_CMSG_AUTH_PASSWORD 9 /* 0x9 */
25#define SSH1_CMSG_REQUEST_PTY 10 /* 0xa */
26#define SSH1_CMSG_WINDOW_SIZE 11 /* 0xb */
27#define SSH1_CMSG_EXEC_SHELL 12 /* 0xc */
28#define SSH1_CMSG_EXEC_CMD 13 /* 0xd */
29#define SSH1_SMSG_SUCCESS 14 /* 0xe */
30#define SSH1_SMSG_FAILURE 15 /* 0xf */
31#define SSH1_CMSG_STDIN_DATA 16 /* 0x10 */
32#define SSH1_SMSG_STDOUT_DATA 17 /* 0x11 */
33#define SSH1_SMSG_STDERR_DATA 18 /* 0x12 */
34#define SSH1_CMSG_EOF 19 /* 0x13 */
35#define SSH1_SMSG_EXIT_STATUS 20 /* 0x14 */
36#define SSH1_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* 0x15 */
37#define SSH1_MSG_CHANNEL_OPEN_FAILURE 22 /* 0x16 */
38#define SSH1_MSG_CHANNEL_DATA 23 /* 0x17 */
39#define SSH1_MSG_CHANNEL_CLOSE 24 /* 0x18 */
40#define SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* 0x19 */
41#define SSH1_SMSG_X11_OPEN 27 /* 0x1b */
42#define SSH1_CMSG_PORT_FORWARD_REQUEST 28 /* 0x1c */
43#define SSH1_MSG_PORT_OPEN 29 /* 0x1d */
44#define SSH1_CMSG_AGENT_REQUEST_FORWARDING 30 /* 0x1e */
45#define SSH1_SMSG_AGENT_OPEN 31 /* 0x1f */
46#define SSH1_MSG_IGNORE 32 /* 0x20 */
47#define SSH1_CMSG_EXIT_CONFIRMATION 33 /* 0x21 */
48#define SSH1_CMSG_X11_REQUEST_FORWARDING 34 /* 0x22 */
49#define SSH1_CMSG_AUTH_RHOSTS_RSA 35 /* 0x23 */
50#define SSH1_MSG_DEBUG 36 /* 0x24 */
51#define SSH1_CMSG_REQUEST_COMPRESSION 37 /* 0x25 */
52#define SSH1_CMSG_AUTH_TIS 39 /* 0x27 */
53#define SSH1_SMSG_AUTH_TIS_CHALLENGE 40 /* 0x28 */
54#define SSH1_CMSG_AUTH_TIS_RESPONSE 41 /* 0x29 */
55#define SSH1_CMSG_AUTH_CCARD 70 /* 0x46 */
56#define SSH1_SMSG_AUTH_CCARD_CHALLENGE 71 /* 0x47 */
57#define SSH1_CMSG_AUTH_CCARD_RESPONSE 72 /* 0x48 */
58
59#define SSH1_AUTH_TIS 5 /* 0x5 */
60#define SSH1_AUTH_CCARD 16 /* 0x10 */
61
62#define SSH1_PROTOFLAG_SCREEN_NUMBER 1 /* 0x1 */
b96dc54c 63/* Mask for protoflags we will echo back to server if seen */
32874aea 64#define SSH1_PROTOFLAGS_SUPPORTED 0 /* 0x1 */
65
66#define SSH2_MSG_DISCONNECT 1 /* 0x1 */
67#define SSH2_MSG_IGNORE 2 /* 0x2 */
68#define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
69#define SSH2_MSG_DEBUG 4 /* 0x4 */
70#define SSH2_MSG_SERVICE_REQUEST 5 /* 0x5 */
71#define SSH2_MSG_SERVICE_ACCEPT 6 /* 0x6 */
72#define SSH2_MSG_KEXINIT 20 /* 0x14 */
73#define SSH2_MSG_NEWKEYS 21 /* 0x15 */
74#define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
75#define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
76#define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
77#define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
78#define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
79#define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
80#define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
81#define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
82#define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
83#define SSH2_MSG_USERAUTH_BANNER 53 /* 0x35 */
84#define SSH2_MSG_USERAUTH_PK_OK 60 /* 0x3c */
85#define SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ 60 /* 0x3c */
761187b6 86#define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
87#define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
32874aea 88#define SSH2_MSG_GLOBAL_REQUEST 80 /* 0x50 */
89#define SSH2_MSG_REQUEST_SUCCESS 81 /* 0x51 */
90#define SSH2_MSG_REQUEST_FAILURE 82 /* 0x52 */
91#define SSH2_MSG_CHANNEL_OPEN 90 /* 0x5a */
92#define SSH2_MSG_CHANNEL_OPEN_CONFIRMATION 91 /* 0x5b */
93#define SSH2_MSG_CHANNEL_OPEN_FAILURE 92 /* 0x5c */
94#define SSH2_MSG_CHANNEL_WINDOW_ADJUST 93 /* 0x5d */
95#define SSH2_MSG_CHANNEL_DATA 94 /* 0x5e */
96#define SSH2_MSG_CHANNEL_EXTENDED_DATA 95 /* 0x5f */
97#define SSH2_MSG_CHANNEL_EOF 96 /* 0x60 */
98#define SSH2_MSG_CHANNEL_CLOSE 97 /* 0x61 */
99#define SSH2_MSG_CHANNEL_REQUEST 98 /* 0x62 */
100#define SSH2_MSG_CHANNEL_SUCCESS 99 /* 0x63 */
101#define SSH2_MSG_CHANNEL_FAILURE 100 /* 0x64 */
102
00db133f 103/*
104 * Packet type contexts, so that ssh2_pkt_type can correctly decode
105 * the ambiguous type numbers back into the correct type strings.
106 */
107#define SSH2_PKTCTX_DHGROUP1 0x0001
108#define SSH2_PKTCTX_DHGEX 0x0002
109#define SSH2_PKTCTX_PUBLICKEY 0x0010
110#define SSH2_PKTCTX_PASSWORD 0x0020
111#define SSH2_PKTCTX_KBDINTER 0x0040
112#define SSH2_PKTCTX_AUTH_MASK 0x00F0
113
32874aea 114#define SSH2_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT 1 /* 0x1 */
115#define SSH2_DISCONNECT_PROTOCOL_ERROR 2 /* 0x2 */
116#define SSH2_DISCONNECT_KEY_EXCHANGE_FAILED 3 /* 0x3 */
117#define SSH2_DISCONNECT_HOST_AUTHENTICATION_FAILED 4 /* 0x4 */
118#define SSH2_DISCONNECT_MAC_ERROR 5 /* 0x5 */
119#define SSH2_DISCONNECT_COMPRESSION_ERROR 6 /* 0x6 */
120#define SSH2_DISCONNECT_SERVICE_NOT_AVAILABLE 7 /* 0x7 */
121#define SSH2_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED 8 /* 0x8 */
122#define SSH2_DISCONNECT_HOST_KEY_NOT_VERIFIABLE 9 /* 0x9 */
123#define SSH2_DISCONNECT_CONNECTION_LOST 10 /* 0xa */
124#define SSH2_DISCONNECT_BY_APPLICATION 11 /* 0xb */
125#define SSH2_DISCONNECT_TOO_MANY_CONNECTIONS 12 /* 0xc */
126#define SSH2_DISCONNECT_AUTH_CANCELLED_BY_USER 13 /* 0xd */
127#define SSH2_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE 14 /* 0xe */
128#define SSH2_DISCONNECT_ILLEGAL_USER_NAME 15 /* 0xf */
38c4a8da 129
130static const char *const ssh2_disconnect_reasons[] = {
131 NULL,
132 "SSH_DISCONNECT_HOST_NOT_ALLOWED_TO_CONNECT",
133 "SSH_DISCONNECT_PROTOCOL_ERROR",
134 "SSH_DISCONNECT_KEY_EXCHANGE_FAILED",
135 "SSH_DISCONNECT_HOST_AUTHENTICATION_FAILED",
136 "SSH_DISCONNECT_MAC_ERROR",
137 "SSH_DISCONNECT_COMPRESSION_ERROR",
138 "SSH_DISCONNECT_SERVICE_NOT_AVAILABLE",
139 "SSH_DISCONNECT_PROTOCOL_VERSION_NOT_SUPPORTED",
140 "SSH_DISCONNECT_HOST_KEY_NOT_VERIFIABLE",
141 "SSH_DISCONNECT_CONNECTION_LOST",
142 "SSH_DISCONNECT_BY_APPLICATION",
143 "SSH_DISCONNECT_TOO_MANY_CONNECTIONS",
144 "SSH_DISCONNECT_AUTH_CANCELLED_BY_USER",
145 "SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE",
146 "SSH_DISCONNECT_ILLEGAL_USER_NAME",
147};
9005f3ba 148
32874aea 149#define SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED 1 /* 0x1 */
150#define SSH2_OPEN_CONNECT_FAILED 2 /* 0x2 */
151#define SSH2_OPEN_UNKNOWN_CHANNEL_TYPE 3 /* 0x3 */
152#define SSH2_OPEN_RESOURCE_SHORTAGE 4 /* 0x4 */
d211621f 153
32874aea 154#define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
fb09bf1c 155
7d503c31 156/*
157 * Various remote-bug flags.
158 */
159#define BUG_CHOKES_ON_SSH1_IGNORE 1
160#define BUG_SSH2_HMAC 2
bd358db1 161#define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
0df73905 162#define BUG_CHOKES_ON_RSA 8
1dd353b5 163#define BUG_SSH2_RSA_PADDING 16
088bde77 164#define BUG_SSH2_DERIVEKEY 32
8e975795 165#define BUG_SSH2_DH_GEX 64
bd358db1 166
00db133f 167#define translate(x) if (type == x) return #x
51470298 168#define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
00db133f 169char *ssh1_pkt_type(int type)
170{
171 translate(SSH1_MSG_DISCONNECT);
172 translate(SSH1_SMSG_PUBLIC_KEY);
173 translate(SSH1_CMSG_SESSION_KEY);
174 translate(SSH1_CMSG_USER);
175 translate(SSH1_CMSG_AUTH_RSA);
176 translate(SSH1_SMSG_AUTH_RSA_CHALLENGE);
177 translate(SSH1_CMSG_AUTH_RSA_RESPONSE);
178 translate(SSH1_CMSG_AUTH_PASSWORD);
179 translate(SSH1_CMSG_REQUEST_PTY);
180 translate(SSH1_CMSG_WINDOW_SIZE);
181 translate(SSH1_CMSG_EXEC_SHELL);
182 translate(SSH1_CMSG_EXEC_CMD);
183 translate(SSH1_SMSG_SUCCESS);
184 translate(SSH1_SMSG_FAILURE);
185 translate(SSH1_CMSG_STDIN_DATA);
186 translate(SSH1_SMSG_STDOUT_DATA);
187 translate(SSH1_SMSG_STDERR_DATA);
188 translate(SSH1_CMSG_EOF);
189 translate(SSH1_SMSG_EXIT_STATUS);
190 translate(SSH1_MSG_CHANNEL_OPEN_CONFIRMATION);
191 translate(SSH1_MSG_CHANNEL_OPEN_FAILURE);
192 translate(SSH1_MSG_CHANNEL_DATA);
193 translate(SSH1_MSG_CHANNEL_CLOSE);
194 translate(SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION);
195 translate(SSH1_SMSG_X11_OPEN);
196 translate(SSH1_CMSG_PORT_FORWARD_REQUEST);
197 translate(SSH1_MSG_PORT_OPEN);
198 translate(SSH1_CMSG_AGENT_REQUEST_FORWARDING);
199 translate(SSH1_SMSG_AGENT_OPEN);
200 translate(SSH1_MSG_IGNORE);
201 translate(SSH1_CMSG_EXIT_CONFIRMATION);
202 translate(SSH1_CMSG_X11_REQUEST_FORWARDING);
203 translate(SSH1_CMSG_AUTH_RHOSTS_RSA);
204 translate(SSH1_MSG_DEBUG);
205 translate(SSH1_CMSG_REQUEST_COMPRESSION);
206 translate(SSH1_CMSG_AUTH_TIS);
207 translate(SSH1_SMSG_AUTH_TIS_CHALLENGE);
208 translate(SSH1_CMSG_AUTH_TIS_RESPONSE);
209 translate(SSH1_CMSG_AUTH_CCARD);
210 translate(SSH1_SMSG_AUTH_CCARD_CHALLENGE);
211 translate(SSH1_CMSG_AUTH_CCARD_RESPONSE);
212 return "unknown";
213}
51470298 214char *ssh2_pkt_type(int pkt_ctx, int type)
00db133f 215{
216 translate(SSH2_MSG_DISCONNECT);
217 translate(SSH2_MSG_IGNORE);
218 translate(SSH2_MSG_UNIMPLEMENTED);
219 translate(SSH2_MSG_DEBUG);
220 translate(SSH2_MSG_SERVICE_REQUEST);
221 translate(SSH2_MSG_SERVICE_ACCEPT);
222 translate(SSH2_MSG_KEXINIT);
223 translate(SSH2_MSG_NEWKEYS);
224 translatec(SSH2_MSG_KEXDH_INIT, SSH2_PKTCTX_DHGROUP1);
225 translatec(SSH2_MSG_KEXDH_REPLY, SSH2_PKTCTX_DHGROUP1);
226 translatec(SSH2_MSG_KEX_DH_GEX_REQUEST, SSH2_PKTCTX_DHGEX);
227 translatec(SSH2_MSG_KEX_DH_GEX_GROUP, SSH2_PKTCTX_DHGEX);
228 translatec(SSH2_MSG_KEX_DH_GEX_INIT, SSH2_PKTCTX_DHGEX);
229 translatec(SSH2_MSG_KEX_DH_GEX_REPLY, SSH2_PKTCTX_DHGEX);
230 translate(SSH2_MSG_USERAUTH_REQUEST);
231 translate(SSH2_MSG_USERAUTH_FAILURE);
232 translate(SSH2_MSG_USERAUTH_SUCCESS);
233 translate(SSH2_MSG_USERAUTH_BANNER);
234 translatec(SSH2_MSG_USERAUTH_PK_OK, SSH2_PKTCTX_PUBLICKEY);
235 translatec(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, SSH2_PKTCTX_PASSWORD);
236 translatec(SSH2_MSG_USERAUTH_INFO_REQUEST, SSH2_PKTCTX_KBDINTER);
237 translatec(SSH2_MSG_USERAUTH_INFO_RESPONSE, SSH2_PKTCTX_KBDINTER);
238 translate(SSH2_MSG_GLOBAL_REQUEST);
239 translate(SSH2_MSG_REQUEST_SUCCESS);
240 translate(SSH2_MSG_REQUEST_FAILURE);
241 translate(SSH2_MSG_CHANNEL_OPEN);
242 translate(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
243 translate(SSH2_MSG_CHANNEL_OPEN_FAILURE);
244 translate(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
245 translate(SSH2_MSG_CHANNEL_DATA);
246 translate(SSH2_MSG_CHANNEL_EXTENDED_DATA);
247 translate(SSH2_MSG_CHANNEL_EOF);
248 translate(SSH2_MSG_CHANNEL_CLOSE);
249 translate(SSH2_MSG_CHANNEL_REQUEST);
250 translate(SSH2_MSG_CHANNEL_SUCCESS);
251 translate(SSH2_MSG_CHANNEL_FAILURE);
252 return "unknown";
253}
254#undef translate
255#undef translatec
7d503c31 256
fb09bf1c 257#define GET_32BIT(cp) \
258 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
259 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
260 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
261 ((unsigned long)(unsigned char)(cp)[3]))
262
263#define PUT_32BIT(cp, value) { \
264 (cp)[0] = (unsigned char)((value) >> 24); \
265 (cp)[1] = (unsigned char)((value) >> 16); \
266 (cp)[2] = (unsigned char)((value) >> 8); \
267 (cp)[3] = (unsigned char)(value); }
268
7cca0d81 269enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
972a41c8 270
374330e2 271/* Coroutine mechanics for the sillier bits of the code */
51470298 272#define crBegin(v) { int *crLine = &v; switch(v) { case 0:;
273#define crState(t) \
274 struct t *s; \
275 if (!ssh->t) ssh->t = smalloc(sizeof(struct t)); \
276 s = ssh->t;
277#define crFinish(z) } *crLine = 0; return (z); }
278#define crFinishV } *crLine = 0; return; }
374330e2 279#define crReturn(z) \
280 do {\
51470298 281 *crLine =__LINE__; return (z); case __LINE__:;\
374330e2 282 } while (0)
283#define crReturnV \
284 do {\
51470298 285 *crLine=__LINE__; return; case __LINE__:;\
374330e2 286 } while (0)
51470298 287#define crStop(z) do{ *crLine = 0; return (z); }while(0)
288#define crStopV do{ *crLine = 0; return; }while(0)
fb09bf1c 289#define crWaitUntil(c) do { crReturn(0); } while (!(c))
7cca0d81 290#define crWaitUntilV(c) do { crReturnV; } while (!(c))
374330e2 291
51470298 292typedef struct ssh_tag *Ssh;
293
302121de 294extern char *x11_init(Socket *, char *, void *, void *);
32874aea 295extern void x11_close(Socket);
5471d09a 296extern int x11_send(Socket, char *, int);
302121de 297extern void *x11_invent_auth(char *, int, char *, int);
5471d09a 298extern void x11_unthrottle(Socket s);
299extern void x11_override_throttle(Socket s, int enable);
9c964e85 300
d74d141c 301extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c);
6b78788a 302extern char *pfd_addforward(char *desthost, int destport, int port,
303 void *backhandle);
d74d141c 304extern void pfd_close(Socket s);
5471d09a 305extern int pfd_send(Socket s, char *data, int len);
d74d141c 306extern void pfd_confirm(Socket s);
5471d09a 307extern void pfd_unthrottle(Socket s);
308extern void pfd_override_throttle(Socket s, int enable);
309
51470298 310static void ssh2_pkt_init(Ssh, int pkt_type);
311static void ssh2_pkt_addbool(Ssh, unsigned char value);
312static void ssh2_pkt_adduint32(Ssh, unsigned long value);
313static void ssh2_pkt_addstring_start(Ssh);
314static void ssh2_pkt_addstring_str(Ssh, char *data);
315static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
316static void ssh2_pkt_addstring(Ssh, char *data);
3d63ca2e 317static char *ssh2_mpint_fmt(Bignum b, int *len);
51470298 318static void ssh2_pkt_addmp(Ssh, Bignum b);
319static int ssh2_pkt_construct(Ssh);
320static void ssh2_pkt_send(Ssh);
3d63ca2e 321
5471d09a 322/*
323 * Buffer management constants. There are several of these for
324 * various different purposes:
325 *
326 * - SSH1_BUFFER_LIMIT is the amount of backlog that must build up
327 * on a local data stream before we throttle the whole SSH
328 * connection (in SSH1 only). Throttling the whole connection is
329 * pretty drastic so we set this high in the hope it won't
330 * happen very often.
331 *
332 * - SSH_MAX_BACKLOG is the amount of backlog that must build up
333 * on the SSH connection itself before we defensively throttle
334 * _all_ local data streams. This is pretty drastic too (though
335 * thankfully unlikely in SSH2 since the window mechanism should
336 * ensure that the server never has any need to throttle its end
337 * of the connection), so we set this high as well.
338 *
339 * - OUR_V2_WINSIZE is the maximum window size we present on SSH2
340 * channels.
341 */
342
343#define SSH1_BUFFER_LIMIT 32768
344#define SSH_MAX_BACKLOG 32768
345#define OUR_V2_WINSIZE 16384
d74d141c 346
a92dd380 347const static struct ssh_kex *kex_algs[] = {
a92dd380 348 &ssh_diffiehellman_gex,
32874aea 349 &ssh_diffiehellman
350};
e5574168 351
85cc02bb 352const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
e5574168 353
e0e1a00d 354static void *nullmac_make_context(void)
355{
356 return NULL;
357}
358static void nullmac_free_context(void *handle)
359{
360}
361static void nullmac_key(void *handle, unsigned char *key)
32874aea 362{
363}
e0e1a00d 364static void nullmac_generate(void *handle, unsigned char *blk, int len,
32874aea 365 unsigned long seq)
366{
367}
e0e1a00d 368static int nullmac_verify(void *handle, unsigned char *blk, int len,
369 unsigned long seq)
32874aea 370{
371 return 1;
372}
57476f6b 373const static struct ssh_mac ssh_mac_none = {
e0e1a00d 374 nullmac_make_context, nullmac_free_context, nullmac_key,
375 nullmac_generate, nullmac_verify, "none", 0
e5574168 376};
8b2715b2 377const static struct ssh_mac *macs[] = {
32874aea 378 &ssh_sha1, &ssh_md5, &ssh_mac_none
379};
8b2715b2 380const static struct ssh_mac *buggymacs[] = {
32874aea 381 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
382};
e5574168 383
5366aed8 384static void *ssh_comp_none_init(void)
385{
386 return NULL;
387}
388static void ssh_comp_none_cleanup(void *handle)
32874aea 389{
390}
5366aed8 391static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
32874aea 392 unsigned char **outblock, int *outlen)
393{
394 return 0;
395}
5366aed8 396static int ssh_comp_none_disable(void *handle)
32874aea 397{
4ba9b64b 398 return 0;
399}
57476f6b 400const static struct ssh_compress ssh_comp_none = {
4ba9b64b 401 "none",
5366aed8 402 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
403 ssh_comp_none_init, ssh_comp_none_cleanup, ssh_comp_none_block,
404 ssh_comp_none_disable, NULL
e5574168 405};
4ba9b64b 406extern const struct ssh_compress ssh_zlib;
407const static struct ssh_compress *compressions[] = {
32874aea 408 &ssh_zlib, &ssh_comp_none
409};
374330e2 410
32874aea 411enum { /* channel types */
783415f8 412 CHAN_MAINSESSION,
413 CHAN_X11,
414 CHAN_AGENT,
bc240b21 415 CHAN_SOCKDATA,
416 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
783415f8 417};
418
dacbd0e8 419/*
420 * 2-3-4 tree storing channels.
421 */
422struct ssh_channel {
51470298 423 Ssh ssh; /* pointer back to main context */
d211621f 424 unsigned remoteid, localid;
dacbd0e8 425 int type;
0357890f 426 /*
427 * In SSH1, this value contains four bits:
428 *
429 * 1 We have sent SSH1_MSG_CHANNEL_CLOSE.
430 * 2 We have sent SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
431 * 4 We have received SSH1_MSG_CHANNEL_CLOSE.
432 * 8 We have received SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION.
433 *
434 * A channel is completely finished with when all four bits are set.
435 */
dacbd0e8 436 int closes;
5471d09a 437 union {
438 struct ssh1_data_channel {
439 int throttling;
440 } v1;
441 struct ssh2_data_channel {
442 bufchain outbuffer;
443 unsigned remwindow, remmaxpkt;
444 unsigned locwindow;
445 } v2;
446 } v;
dacbd0e8 447 union {
32874aea 448 struct ssh_agent_channel {
449 unsigned char *message;
450 unsigned char msglen[4];
451 int lensofar, totallen;
452 } a;
453 struct ssh_x11_channel {
454 Socket s;
455 } x11;
d74d141c 456 struct ssh_pfd_channel {
457 Socket s;
458 } pfd;
dacbd0e8 459 } u;
460};
57476f6b 461
d74d141c 462/*
bc240b21 463 * 2-3-4 tree storing remote->local port forwardings. SSH 1 and SSH
464 * 2 use this structure in different ways, reflecting SSH 2's
465 * altogether saner approach to port forwarding.
466 *
467 * In SSH 1, you arrange a remote forwarding by sending the server
468 * the remote port number, and the local destination host:port.
469 * When a connection comes in, the server sends you back that
470 * host:port pair, and you connect to it. This is a ready-made
471 * security hole if you're not on the ball: a malicious server
472 * could send you back _any_ host:port pair, so if you trustingly
473 * connect to the address it gives you then you've just opened the
474 * entire inside of your corporate network just by connecting
475 * through it to a dodgy SSH server. Hence, we must store a list of
476 * host:port pairs we _are_ trying to forward to, and reject a
477 * connection request from the server if it's not in the list.
478 *
479 * In SSH 2, each side of the connection minds its own business and
480 * doesn't send unnecessary information to the other. You arrange a
481 * remote forwarding by sending the server just the remote port
482 * number. When a connection comes in, the server tells you which
483 * of its ports was connected to; and _you_ have to remember what
484 * local host:port pair went with that port number.
485 *
486 * Hence: in SSH 1 this structure stores host:port pairs we intend
487 * to allow connections to, and is indexed by those host:port
488 * pairs. In SSH 2 it stores a mapping from source port to
489 * destination host:port pair, and is indexed by source port.
d74d141c 490 */
491struct ssh_rportfwd {
bc240b21 492 unsigned sport, dport;
493 char dhost[256];
d74d141c 494};
495
57476f6b 496struct Packet {
497 long length;
498 int type;
499 unsigned char *data;
500 unsigned char *body;
501 long savedpos;
502 long maxlen;
503};
504
51470298 505static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
506static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
507static void ssh_size(void *handle, int width, int height);
508static void ssh_special(void *handle, Telnet_Special);
5471d09a 509static int ssh2_try_send(struct ssh_channel *c);
51470298 510static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
511static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
5471d09a 512static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
51470298 513static int ssh_sendbuffer(void *handle);
57476f6b 514
51470298 515struct rdpkt1_state_tag {
57476f6b 516 long len, pad, biglen, to_read;
517 unsigned long realcrc, gotcrc;
518 unsigned char *p;
519 int i;
520 int chunk;
51470298 521};
57476f6b 522
51470298 523struct rdpkt2_state_tag {
960e736a 524 long len, pad, payload, packetlen, maclen;
525 int i;
526 int cipherblk;
527 unsigned long incoming_sequence;
51470298 528};
529
530struct ssh_tag {
531 const struct plug_function_table *fn;
532 /* the above field _must_ be first in the structure */
533
534 SHA_State exhash, exhashbase;
535
536 Socket s;
537
b9d7bcad 538 void *ldisc;
a8327734 539 void *logctx;
b9d7bcad 540
51470298 541 unsigned char session_key[32];
542 int v1_compressing;
543 int v1_remote_protoflags;
544 int v1_local_protoflags;
545 int agentfwd_enabled;
546 int X11_fwd_enabled;
547 int remote_bugs;
548 const struct ssh_cipher *cipher;
371e569c 549 void *v1_cipher_ctx;
0183b242 550 void *crcda_ctx;
51470298 551 const struct ssh2_cipher *cscipher, *sccipher;
371e569c 552 void *cs_cipher_ctx, *sc_cipher_ctx;
51470298 553 const struct ssh_mac *csmac, *scmac;
e0e1a00d 554 void *cs_mac_ctx, *sc_mac_ctx;
51470298 555 const struct ssh_compress *cscomp, *sccomp;
5366aed8 556 void *cs_comp_ctx, *sc_comp_ctx;
51470298 557 const struct ssh_kex *kex;
558 const struct ssh_signkey *hostkey;
559 unsigned char v2_session_id[20];
27cd7fc2 560 void *kex_ctx;
51470298 561
562 char *savedhost;
563 int savedport;
564 int send_ok;
565 int echoing, editing;
566
567 void *frontend;
568
569 int term_width, term_height;
570
571 tree234 *channels; /* indexed by local id */
572 struct ssh_channel *mainchan; /* primary session channel */
573 int exitcode;
574
575 tree234 *rportfwds;
576
577 enum {
578 SSH_STATE_PREPACKET,
579 SSH_STATE_BEFORE_SIZE,
580 SSH_STATE_INTERMED,
581 SSH_STATE_SESSION,
582 SSH_STATE_CLOSED
583 } state;
584
585 int size_needed, eof_needed;
586
587 struct Packet pktin;
588 struct Packet pktout;
589 unsigned char *deferred_send_data;
590 int deferred_len, deferred_size;
591
592 /*
593 * Gross hack: pscp will try to start SFTP but fall back to
594 * scp1 if that fails. This variable is the means by which
595 * scp.c can reach into the SSH code and find out which one it
596 * got.
597 */
598 int fallback_cmd;
599
600 /*
601 * Used for username and password input.
602 */
603 char *userpass_input_buffer;
604 int userpass_input_buflen;
605 int userpass_input_bufpos;
606 int userpass_input_echo;
607
608 char *portfwd_strptr;
609 int pkt_ctx;
610
302121de 611 void *x11auth;
612
51470298 613 int version;
614 int v1_throttle_count;
615 int overall_bufsize;
616 int throttled_all;
617 int v1_stdout_throttling;
618 int v2_outgoing_sequence;
619
620 int ssh1_rdpkt_crstate;
621 int ssh2_rdpkt_crstate;
622 int do_ssh_init_crstate;
623 int ssh_gotdata_crstate;
624 int ssh1_protocol_crstate;
625 int do_ssh1_login_crstate;
626 int do_ssh2_transport_crstate;
627 int do_ssh2_authconn_crstate;
628
629 void *do_ssh_init_state;
630 void *do_ssh1_login_state;
631 void *do_ssh2_transport_state;
632 void *do_ssh2_authconn_state;
633
634 struct rdpkt1_state_tag rdpkt1_state;
635 struct rdpkt2_state_tag rdpkt2_state;
636
637 void (*protocol) (Ssh ssh, unsigned char *in, int inlen, int ispkt);
638 int (*s_rdpkt) (Ssh ssh, unsigned char **data, int *datalen);
639};
960e736a 640
a8327734 641#define logevent(s) { logevent(ssh->frontend, s); \
642 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
643 { fprintf(stderr, "%s\n", s); fflush(stderr); } }
644
645/* logevent, only printf-formatted. */
646void logeventf(Ssh ssh, char *fmt, ...)
647{
648 va_list ap;
649 char stuff[200];
650
651 va_start(ap, fmt);
652 vsprintf(stuff, fmt, ap);
653 va_end(ap);
654 logevent(stuff);
655}
656
657#define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
658 (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \
659 logeventf msg, connection_fatal msg )
660
32874aea 661static int ssh_channelcmp(void *av, void *bv)
662{
663 struct ssh_channel *a = (struct ssh_channel *) av;
664 struct ssh_channel *b = (struct ssh_channel *) bv;
665 if (a->localid < b->localid)
666 return -1;
667 if (a->localid > b->localid)
668 return +1;
dacbd0e8 669 return 0;
670}
32874aea 671static int ssh_channelfind(void *av, void *bv)
672{
673 unsigned *a = (unsigned *) av;
674 struct ssh_channel *b = (struct ssh_channel *) bv;
675 if (*a < b->localid)
676 return -1;
677 if (*a > b->localid)
678 return +1;
dacbd0e8 679 return 0;
680}
681
bc240b21 682static int ssh_rportcmp_ssh1(void *av, void *bv)
d74d141c 683{
684 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
685 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
686 int i;
bc240b21 687 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
d74d141c 688 return i < 0 ? -1 : +1;
bc240b21 689 if (a->dport > b->dport)
690 return +1;
691 if (a->dport < b->dport)
692 return -1;
693 return 0;
694}
695
696static int ssh_rportcmp_ssh2(void *av, void *bv)
697{
698 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
699 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
cdcbdf3b 700
bc240b21 701 if (a->sport > b->sport)
d74d141c 702 return +1;
bc240b21 703 if (a->sport < b->sport)
704 return -1;
d74d141c 705 return 0;
706}
707
51470298 708static int alloc_channel_id(Ssh ssh)
32874aea 709{
260f3dec 710 const unsigned CHANNEL_NUMBER_OFFSET = 256;
711 unsigned low, high, mid;
d2371c81 712 int tsize;
713 struct ssh_channel *c;
714
715 /*
716 * First-fit allocation of channel numbers: always pick the
717 * lowest unused one. To do this, binary-search using the
718 * counted B-tree to find the largest channel ID which is in a
719 * contiguous sequence from the beginning. (Precisely
720 * everything in that sequence must have ID equal to its tree
721 * index plus CHANNEL_NUMBER_OFFSET.)
722 */
51470298 723 tsize = count234(ssh->channels);
d2371c81 724
32874aea 725 low = -1;
726 high = tsize;
d2371c81 727 while (high - low > 1) {
728 mid = (high + low) / 2;
51470298 729 c = index234(ssh->channels, mid);
d2371c81 730 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
731 low = mid; /* this one is fine */
732 else
733 high = mid; /* this one is past it */
734 }
735 /*
736 * Now low points to either -1, or the tree index of the
737 * largest ID in the initial sequence.
738 */
739 {
740 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
51470298 741 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
d2371c81 742 }
743 return low + 1 + CHANNEL_NUMBER_OFFSET;
744}
745
51470298 746static void c_write(Ssh ssh, char *buf, int len)
32874aea 747{
67779be7 748 if ((flags & FLAG_STDERR)) {
32874aea 749 int i;
750 for (i = 0; i < len; i++)
751 if (buf[i] != '\r')
752 fputc(buf[i], stderr);
fb09bf1c 753 return;
754 }
51470298 755 from_backend(ssh->frontend, 1, buf, len);
3bdaf79d 756}
757
51470298 758static void c_write_untrusted(Ssh ssh, char *buf, int len)
32874aea 759{
a209e957 760 int i;
761 for (i = 0; i < len; i++) {
32874aea 762 if (buf[i] == '\n')
51470298 763 c_write(ssh, "\r\n", 2);
32874aea 764 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
51470298 765 c_write(ssh, buf + i, 1);
a209e957 766 }
767}
768
51470298 769static void c_write_str(Ssh ssh, char *buf)
32874aea 770{
51470298 771 c_write(ssh, buf, strlen(buf));
1408a877 772}
773
fb09bf1c 774/*
775 * Collect incoming data in the incoming packet buffer.
e5574168 776 * Decipher and verify the packet when it is completely read.
777 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
fb09bf1c 778 * Update the *data and *datalen variables.
779 * Return the additional nr of bytes needed, or 0 when
780 * a complete packet is available.
781 */
51470298 782static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
fb09bf1c 783{
51470298 784 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
374330e2 785
51470298 786 crBegin(ssh->ssh1_rdpkt_crstate);
374330e2 787
32874aea 788 next_packet:
37508af4 789
51470298 790 ssh->pktin.type = 0;
791 ssh->pktin.length = 0;
374330e2 792
57476f6b 793 for (st->i = st->len = 0; st->i < 4; st->i++) {
fb09bf1c 794 while ((*datalen) == 0)
32874aea 795 crReturn(4 - st->i);
57476f6b 796 st->len = (st->len << 8) + **data;
fb09bf1c 797 (*data)++, (*datalen)--;
798 }
374330e2 799
57476f6b 800 st->pad = 8 - (st->len % 8);
801 st->biglen = st->len + st->pad;
51470298 802 ssh->pktin.length = st->len - 5;
fb09bf1c 803
51470298 804 if (ssh->pktin.maxlen < st->biglen) {
805 ssh->pktin.maxlen = st->biglen;
806 ssh->pktin.data = srealloc(ssh->pktin.data, st->biglen + APIEXTRA);
fb09bf1c 807 }
374330e2 808
57476f6b 809 st->to_read = st->biglen;
51470298 810 st->p = ssh->pktin.data;
57476f6b 811 while (st->to_read > 0) {
32874aea 812 st->chunk = st->to_read;
fb09bf1c 813 while ((*datalen) == 0)
57476f6b 814 crReturn(st->to_read);
815 if (st->chunk > (*datalen))
816 st->chunk = (*datalen);
817 memcpy(st->p, *data, st->chunk);
818 *data += st->chunk;
819 *datalen -= st->chunk;
820 st->p += st->chunk;
821 st->to_read -= st->chunk;
fb09bf1c 822 }
374330e2 823
0183b242 824 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
825 st->biglen, NULL)) {
a8327734 826 bombout((ssh,"Network attack (CRC compensation) detected!"));
9a3a93a5 827 crReturn(0);
828 }
829
51470298 830 if (ssh->cipher)
371e569c 831 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
374330e2 832
51470298 833 st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
834 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
57476f6b 835 if (st->gotcrc != st->realcrc) {
a8327734 836 bombout((ssh,"Incorrect CRC received on packet"));
32874aea 837 crReturn(0);
fb09bf1c 838 }
572f871e 839
51470298 840 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
4ba9b64b 841
51470298 842 if (ssh->v1_compressing) {
4ba9b64b 843 unsigned char *decompblk;
844 int decomplen;
5366aed8 845 zlib_decompress_block(ssh->sc_comp_ctx,
846 ssh->pktin.body - 1, ssh->pktin.length + 1,
4ba9b64b 847 &decompblk, &decomplen);
848
51470298 849 if (ssh->pktin.maxlen < st->pad + decomplen) {
850 ssh->pktin.maxlen = st->pad + decomplen;
851 ssh->pktin.data = srealloc(ssh->pktin.data,
852 ssh->pktin.maxlen + APIEXTRA);
853 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
4ba9b64b 854 }
855
51470298 856 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
dcbde236 857 sfree(decompblk);
51470298 858 ssh->pktin.length = decomplen - 1;
4ba9b64b 859 }
860
51470298 861 ssh->pktin.type = ssh->pktin.body[-1];
00db133f 862
a8327734 863 if (ssh->logctx)
864 log_packet(ssh->logctx,
865 PKT_INCOMING, ssh->pktin.type,
866 ssh1_pkt_type(ssh->pktin.type),
867 ssh->pktin.body, ssh->pktin.length);
00db133f 868
51470298 869 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
870 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
871 ssh->pktin.type == SSH1_MSG_DEBUG ||
872 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
873 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
874 long stringlen = GET_32BIT(ssh->pktin.body);
875 if (stringlen + 4 != ssh->pktin.length) {
a8327734 876 bombout((ssh,"Received data packet with bogus string length"));
32874aea 877 crReturn(0);
878 }
fb09bf1c 879 }
880
51470298 881 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
fb09bf1c 882 /* log debug message */
eb4504cc 883 char buf[512];
51470298 884 int stringlen = GET_32BIT(ssh->pktin.body);
eb4504cc 885 strcpy(buf, "Remote debug message: ");
886 if (stringlen > 480)
887 stringlen = 480;
51470298 888 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
3d63ca2e 889 buf[8 + stringlen] = '\0';
fb09bf1c 890 logevent(buf);
891 goto next_packet;
51470298 892 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
fb09bf1c 893 /* do nothing */
894 goto next_packet;
895 }
896
51470298 897 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
38c4a8da 898 /* log reason code in disconnect message */
899 char buf[256];
51470298 900 unsigned msglen = GET_32BIT(ssh->pktin.body);
260f3dec 901 unsigned nowlen;
38c4a8da 902 strcpy(buf, "Remote sent disconnect: ");
903 nowlen = strlen(buf);
32874aea 904 if (msglen > sizeof(buf) - nowlen - 1)
905 msglen = sizeof(buf) - nowlen - 1;
51470298 906 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
32874aea 907 buf[nowlen + msglen] = '\0';
247308b5 908 /* logevent(buf); (this is now done within the bombout macro) */
a8327734 909 bombout((ssh,"Server sent disconnect message:\n\"%s\"", buf+nowlen));
e14d0f19 910 crReturn(0);
38c4a8da 911 }
912
fb09bf1c 913 crFinish(0);
914}
915
51470298 916static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
e5574168 917{
51470298 918 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
e5574168 919
51470298 920 crBegin(ssh->ssh2_rdpkt_crstate);
e5574168 921
32874aea 922 next_packet:
51470298 923 ssh->pktin.type = 0;
924 ssh->pktin.length = 0;
925 if (ssh->sccipher)
926 st->cipherblk = ssh->sccipher->blksize;
e5574168 927 else
32874aea 928 st->cipherblk = 8;
960e736a 929 if (st->cipherblk < 8)
32874aea 930 st->cipherblk = 8;
960e736a 931
51470298 932 if (ssh->pktin.maxlen < st->cipherblk) {
933 ssh->pktin.maxlen = st->cipherblk;
934 ssh->pktin.data = srealloc(ssh->pktin.data, st->cipherblk + APIEXTRA);
e5574168 935 }
936
937 /*
938 * Acquire and decrypt the first block of the packet. This will
939 * contain the length and padding details.
940 */
32874aea 941 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
e5574168 942 while ((*datalen) == 0)
32874aea 943 crReturn(st->cipherblk - st->i);
51470298 944 ssh->pktin.data[st->i] = *(*data)++;
32874aea 945 (*datalen)--;
e5574168 946 }
4252c9cc 947
51470298 948 if (ssh->sccipher)
371e569c 949 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
950 ssh->pktin.data, st->cipherblk);
e5574168 951
952 /*
953 * Now get the length and padding figures.
954 */
51470298 955 st->len = GET_32BIT(ssh->pktin.data);
956 st->pad = ssh->pktin.data[4];
e5574168 957
958 /*
717dc483 959 * _Completely_ silly lengths should be stomped on before they
960 * do us any more damage.
961 */
962 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
a8327734 963 bombout((ssh,"Incoming packet was garbled on decryption"));
717dc483 964 crReturn(0);
965 }
966
967 /*
e5574168 968 * This enables us to deduce the payload length.
969 */
960e736a 970 st->payload = st->len - st->pad - 1;
e5574168 971
51470298 972 ssh->pktin.length = st->payload + 5;
e5574168 973
974 /*
975 * So now we can work out the total packet length.
976 */
960e736a 977 st->packetlen = st->len + 4;
51470298 978 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
e5574168 979
980 /*
981 * Adjust memory allocation if packet is too big.
982 */
51470298 983 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
984 ssh->pktin.maxlen = st->packetlen + st->maclen;
985 ssh->pktin.data = srealloc(ssh->pktin.data,
986 ssh->pktin.maxlen + APIEXTRA);
e5574168 987 }
988
989 /*
990 * Read and decrypt the remainder of the packet.
991 */
32874aea 992 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
993 st->i++) {
e5574168 994 while ((*datalen) == 0)
960e736a 995 crReturn(st->packetlen + st->maclen - st->i);
51470298 996 ssh->pktin.data[st->i] = *(*data)++;
32874aea 997 (*datalen)--;
e5574168 998 }
999 /* Decrypt everything _except_ the MAC. */
51470298 1000 if (ssh->sccipher)
371e569c 1001 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1002 ssh->pktin.data + st->cipherblk,
51470298 1003 st->packetlen - st->cipherblk);
e5574168 1004
1005 /*
1006 * Check the MAC.
1007 */
51470298 1008 if (ssh->scmac
e0e1a00d 1009 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
51470298 1010 st->incoming_sequence)) {
a8327734 1011 bombout((ssh,"Incorrect MAC received on packet"));
32874aea 1012 crReturn(0);
8d5de777 1013 }
32874aea 1014 st->incoming_sequence++; /* whether or not we MACed */
e5574168 1015
4ba9b64b 1016 /*
1017 * Decompress packet payload.
1018 */
1019 {
1020 unsigned char *newpayload;
1021 int newlen;
51470298 1022 if (ssh->sccomp &&
5366aed8 1023 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1024 ssh->pktin.data + 5, ssh->pktin.length - 5,
51470298 1025 &newpayload, &newlen)) {
1026 if (ssh->pktin.maxlen < newlen + 5) {
1027 ssh->pktin.maxlen = newlen + 5;
1028 ssh->pktin.data = srealloc(ssh->pktin.data,
1029 ssh->pktin.maxlen + APIEXTRA);
4ba9b64b 1030 }
51470298 1031 ssh->pktin.length = 5 + newlen;
1032 memcpy(ssh->pktin.data + 5, newpayload, newlen);
dcbde236 1033 sfree(newpayload);
4ba9b64b 1034 }
1035 }
1036
51470298 1037 ssh->pktin.savedpos = 6;
1038 ssh->pktin.type = ssh->pktin.data[5];
e5574168 1039
a8327734 1040 if (ssh->logctx)
1041 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1042 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1043 ssh->pktin.data+6, ssh->pktin.length-6);
00db133f 1044
51470298 1045 switch (ssh->pktin.type) {
3d63ca2e 1046 /*
1047 * These packets we must handle instantly.
1048 */
1049 case SSH2_MSG_DISCONNECT:
1050 {
1051 /* log reason code in disconnect message */
1052 char buf[256];
51470298 1053 int reason = GET_32BIT(ssh->pktin.data + 6);
1054 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
3d63ca2e 1055 unsigned nowlen;
1056 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1057 sprintf(buf, "Received disconnect message (%s)",
1058 ssh2_disconnect_reasons[reason]);
1059 } else {
1060 sprintf(buf, "Received disconnect message (unknown type %d)",
1061 reason);
1062 }
1063 logevent(buf);
1064 strcpy(buf, "Disconnection message text: ");
1065 nowlen = strlen(buf);
1066 if (msglen > sizeof(buf) - nowlen - 1)
1067 msglen = sizeof(buf) - nowlen - 1;
51470298 1068 memcpy(buf + nowlen, ssh->pktin.data + 14, msglen);
3d63ca2e 1069 buf[nowlen + msglen] = '\0';
1070 logevent(buf);
a8327734 1071 bombout((ssh,"Server sent disconnect message\ntype %d (%s):\n\"%s\"",
3d63ca2e 1072 reason,
1073 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1074 ssh2_disconnect_reasons[reason] : "unknown",
1075 buf+nowlen));
1076 crReturn(0);
1077 }
1078 break;
1079 case SSH2_MSG_IGNORE:
1080 goto next_packet;
1081 case SSH2_MSG_DEBUG:
1082 {
1083 /* log the debug message */
1084 char buf[512];
51470298 1085 /* int display = ssh->pktin.body[6]; */
1086 int stringlen = GET_32BIT(ssh->pktin.data+7);
3d63ca2e 1087 int prefix;
1088 strcpy(buf, "Remote debug message: ");
1089 prefix = strlen(buf);
51470298 1090 if (stringlen > (int)(sizeof(buf)-prefix-1))
3d63ca2e 1091 stringlen = sizeof(buf)-prefix-1;
51470298 1092 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
3d63ca2e 1093 buf[prefix + stringlen] = '\0';
1094 logevent(buf);
38c4a8da 1095 }
3d63ca2e 1096 goto next_packet; /* FIXME: print the debug message */
1097
1098 /*
1099 * These packets we need do nothing about here.
1100 */
1101 case SSH2_MSG_UNIMPLEMENTED:
1102 case SSH2_MSG_SERVICE_REQUEST:
1103 case SSH2_MSG_SERVICE_ACCEPT:
1104 case SSH2_MSG_KEXINIT:
1105 case SSH2_MSG_NEWKEYS:
1106 case SSH2_MSG_KEXDH_INIT:
1107 case SSH2_MSG_KEXDH_REPLY:
1108 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1109 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1110 case SSH2_MSG_KEX_DH_GEX_INIT:
1111 case SSH2_MSG_KEX_DH_GEX_REPLY:
1112 case SSH2_MSG_USERAUTH_REQUEST:
1113 case SSH2_MSG_USERAUTH_FAILURE:
1114 case SSH2_MSG_USERAUTH_SUCCESS:
1115 case SSH2_MSG_USERAUTH_BANNER:
1116 case SSH2_MSG_USERAUTH_PK_OK:
1117 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1118 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1119 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1120 case SSH2_MSG_GLOBAL_REQUEST:
1121 case SSH2_MSG_REQUEST_SUCCESS:
1122 case SSH2_MSG_REQUEST_FAILURE:
1123 case SSH2_MSG_CHANNEL_OPEN:
1124 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1125 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1126 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1127 case SSH2_MSG_CHANNEL_DATA:
1128 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1129 case SSH2_MSG_CHANNEL_EOF:
1130 case SSH2_MSG_CHANNEL_CLOSE:
1131 case SSH2_MSG_CHANNEL_REQUEST:
1132 case SSH2_MSG_CHANNEL_SUCCESS:
1133 case SSH2_MSG_CHANNEL_FAILURE:
1134 break;
1135
1136 /*
1137 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1138 */
1139 default:
51470298 1140 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1141 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1142 ssh2_pkt_send(ssh);
3d63ca2e 1143 break;
38c4a8da 1144 }
1145
e5574168 1146 crFinish(0);
1147}
1148
51470298 1149static void ssh1_pktout_size(Ssh ssh, int len)
32874aea 1150{
374330e2 1151 int pad, biglen;
1152
1153 len += 5; /* type and CRC */
32874aea 1154 pad = 8 - (len % 8);
374330e2 1155 biglen = len + pad;
1156
51470298 1157 ssh->pktout.length = len - 5;
1158 if (ssh->pktout.maxlen < biglen) {
1159 ssh->pktout.maxlen = biglen;
8f203108 1160#ifdef MSCRYPTOAPI
fb09bf1c 1161 /* Allocate enough buffer space for extra block
8f203108 1162 * for MS CryptEncrypt() */
51470298 1163 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 12);
8f203108 1164#else
51470298 1165 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 4);
8f203108 1166#endif
374330e2 1167 }
51470298 1168 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
4ba9b64b 1169}
374330e2 1170
51470298 1171static void s_wrpkt_start(Ssh ssh, int type, int len)
32874aea 1172{
51470298 1173 ssh1_pktout_size(ssh, len);
1174 ssh->pktout.type = type;
374330e2 1175}
1176
51470298 1177static int s_wrpkt_prepare(Ssh ssh)
32874aea 1178{
374330e2 1179 int pad, len, biglen, i;
1180 unsigned long crc;
1181
51470298 1182 ssh->pktout.body[-1] = ssh->pktout.type;
4ba9b64b 1183
a8327734 1184 if (ssh->logctx)
1185 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1186 ssh1_pkt_type(ssh->pktout.type),
1187 ssh->pktout.body, ssh->pktout.length);
00db133f 1188
51470298 1189 if (ssh->v1_compressing) {
4ba9b64b 1190 unsigned char *compblk;
1191 int complen;
5366aed8 1192 zlib_compress_block(ssh->cs_comp_ctx,
1193 ssh->pktout.body - 1, ssh->pktout.length + 1,
4ba9b64b 1194 &compblk, &complen);
51470298 1195 ssh1_pktout_size(ssh, complen - 1);
1196 memcpy(ssh->pktout.body - 1, compblk, complen);
dcbde236 1197 sfree(compblk);
4ba9b64b 1198 }
1199
51470298 1200 len = ssh->pktout.length + 5; /* type and CRC */
32874aea 1201 pad = 8 - (len % 8);
374330e2 1202 biglen = len + pad;
1203
32874aea 1204 for (i = 0; i < pad; i++)
51470298 1205 ssh->pktout.data[i + 4] = random_byte();
1206 crc = crc32(ssh->pktout.data + 4, biglen - 4);
1207 PUT_32BIT(ssh->pktout.data + biglen, crc);
1208 PUT_32BIT(ssh->pktout.data, len);
374330e2 1209
51470298 1210 if (ssh->cipher)
371e569c 1211 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
374330e2 1212
32874aea 1213 return biglen + 4;
39065bed 1214}
1215
51470298 1216static void s_wrpkt(Ssh ssh)
32874aea 1217{
5471d09a 1218 int len, backlog;
51470298 1219 len = s_wrpkt_prepare(ssh);
1220 backlog = sk_write(ssh->s, ssh->pktout.data, len);
5471d09a 1221 if (backlog > SSH_MAX_BACKLOG)
51470298 1222 ssh_throttle_all(ssh, 1, backlog);
39065bed 1223}
1224
51470298 1225static void s_wrpkt_defer(Ssh ssh)
32874aea 1226{
39065bed 1227 int len;
51470298 1228 len = s_wrpkt_prepare(ssh);
1229 if (ssh->deferred_len + len > ssh->deferred_size) {
1230 ssh->deferred_size = ssh->deferred_len + len + 128;
1231 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1232 ssh->deferred_size);
39065bed 1233 }
51470298 1234 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1235 ssh->deferred_len += len;
374330e2 1236}
1237
fb09bf1c 1238/*
39065bed 1239 * Construct a packet with the specified contents.
fb09bf1c 1240 */
51470298 1241static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
fb09bf1c 1242{
fb09bf1c 1243 unsigned char *p, *argp, argchar;
1244 unsigned long argint;
1245 int pktlen, argtype, arglen;
7cca0d81 1246 Bignum bn;
fb09bf1c 1247
1248 pktlen = 0;
39065bed 1249 while ((argtype = va_arg(ap1, int)) != PKT_END) {
fb09bf1c 1250 switch (argtype) {
1251 case PKT_INT:
39065bed 1252 (void) va_arg(ap1, int);
fb09bf1c 1253 pktlen += 4;
1254 break;
1255 case PKT_CHAR:
1ec39246 1256 (void) va_arg(ap1, int);
fb09bf1c 1257 pktlen++;
1258 break;
1259 case PKT_DATA:
39065bed 1260 (void) va_arg(ap1, unsigned char *);
1261 arglen = va_arg(ap1, int);
fb09bf1c 1262 pktlen += arglen;
1263 break;
1264 case PKT_STR:
39065bed 1265 argp = va_arg(ap1, unsigned char *);
fb09bf1c 1266 arglen = strlen(argp);
1267 pktlen += 4 + arglen;
1268 break;
7cca0d81 1269 case PKT_BIGNUM:
39065bed 1270 bn = va_arg(ap1, Bignum);
32874aea 1271 pktlen += ssh1_bignum_length(bn);
7cca0d81 1272 break;
fb09bf1c 1273 default:
1274 assert(0);
1275 }
1276 }
fb09bf1c 1277
51470298 1278 s_wrpkt_start(ssh, pkttype, pktlen);
1279 p = ssh->pktout.body;
fb09bf1c 1280
39065bed 1281 while ((argtype = va_arg(ap2, int)) != PKT_END) {
fb09bf1c 1282 switch (argtype) {
1283 case PKT_INT:
39065bed 1284 argint = va_arg(ap2, int);
fb09bf1c 1285 PUT_32BIT(p, argint);
1286 p += 4;
1287 break;
1288 case PKT_CHAR:
1ec39246 1289 argchar = (unsigned char) va_arg(ap2, int);
fb09bf1c 1290 *p = argchar;
1291 p++;
1292 break;
1293 case PKT_DATA:
39065bed 1294 argp = va_arg(ap2, unsigned char *);
1295 arglen = va_arg(ap2, int);
fb09bf1c 1296 memcpy(p, argp, arglen);
1297 p += arglen;
1298 break;
1299 case PKT_STR:
39065bed 1300 argp = va_arg(ap2, unsigned char *);
fb09bf1c 1301 arglen = strlen(argp);
1302 PUT_32BIT(p, arglen);
1303 memcpy(p + 4, argp, arglen);
1304 p += 4 + arglen;
1305 break;
7cca0d81 1306 case PKT_BIGNUM:
39065bed 1307 bn = va_arg(ap2, Bignum);
32874aea 1308 p += ssh1_write_bignum(p, bn);
7cca0d81 1309 break;
fb09bf1c 1310 }
1311 }
39065bed 1312}
fb09bf1c 1313
51470298 1314static void send_packet(Ssh ssh, int pkttype, ...)
32874aea 1315{
39065bed 1316 va_list ap1, ap2;
1317 va_start(ap1, pkttype);
1318 va_start(ap2, pkttype);
51470298 1319 construct_packet(ssh, pkttype, ap1, ap2);
1320 s_wrpkt(ssh);
fb09bf1c 1321}
1322
51470298 1323static void defer_packet(Ssh ssh, int pkttype, ...)
32874aea 1324{
39065bed 1325 va_list ap1, ap2;
1326 va_start(ap1, pkttype);
1327 va_start(ap2, pkttype);
51470298 1328 construct_packet(ssh, pkttype, ap1, ap2);
1329 s_wrpkt_defer(ssh);
39065bed 1330}
1331
32874aea 1332static int ssh_versioncmp(char *a, char *b)
1333{
9697bfd2 1334 char *ae, *be;
1335 unsigned long av, bv;
1336
43aa02a7 1337 av = strtoul(a, &ae, 10);
1338 bv = strtoul(b, &be, 10);
32874aea 1339 if (av != bv)
1340 return (av < bv ? -1 : +1);
1341 if (*ae == '.')
1342 ae++;
1343 if (*be == '.')
1344 be++;
43aa02a7 1345 av = strtoul(ae, &ae, 10);
1346 bv = strtoul(be, &be, 10);
32874aea 1347 if (av != bv)
1348 return (av < bv ? -1 : +1);
9697bfd2 1349 return 0;
1350}
1351
e5574168 1352/*
a92dd380 1353 * Utility routines for putting an SSH-protocol `string' and
1354 * `uint32' into a SHA state.
e5574168 1355 */
1356#include <stdio.h>
32874aea 1357static void sha_string(SHA_State * s, void *str, int len)
1358{
e5574168 1359 unsigned char lenblk[4];
e5574168 1360 PUT_32BIT(lenblk, len);
e5574168 1361 SHA_Bytes(s, lenblk, 4);
e5574168 1362 SHA_Bytes(s, str, len);
1363}
1364
32874aea 1365static void sha_uint32(SHA_State * s, unsigned i)
1366{
a92dd380 1367 unsigned char intblk[4];
1368 PUT_32BIT(intblk, i);
1369 SHA_Bytes(s, intblk, 4);
1370}
1371
7cca0d81 1372/*
1373 * SSH2 packet construction functions.
1374 */
51470298 1375static void ssh2_pkt_ensure(Ssh ssh, int length)
32874aea 1376{
51470298 1377 if (ssh->pktout.maxlen < length) {
1378 ssh->pktout.maxlen = length + 256;
1379 ssh->pktout.data = srealloc(ssh->pktout.data,
1380 ssh->pktout.maxlen + APIEXTRA);
1381 if (!ssh->pktout.data)
32874aea 1382 fatalbox("Out of memory");
7cca0d81 1383 }
783415f8 1384}
51470298 1385static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
32874aea 1386{
51470298 1387 ssh->pktout.length += len;
1388 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1389 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
7cca0d81 1390}
51470298 1391static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
32874aea 1392{
51470298 1393 ssh2_pkt_adddata(ssh, &byte, 1);
7cca0d81 1394}
51470298 1395static void ssh2_pkt_init(Ssh ssh, int pkt_type)
32874aea 1396{
51470298 1397 ssh->pktout.length = 5;
1398 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
7cca0d81 1399}
51470298 1400static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
32874aea 1401{
51470298 1402 ssh2_pkt_adddata(ssh, &value, 1);
7cca0d81 1403}
51470298 1404static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
32874aea 1405{
7cca0d81 1406 unsigned char x[4];
1407 PUT_32BIT(x, value);
51470298 1408 ssh2_pkt_adddata(ssh, x, 4);
7cca0d81 1409}
51470298 1410static void ssh2_pkt_addstring_start(Ssh ssh)
32874aea 1411{
51470298 1412 ssh2_pkt_adduint32(ssh, 0);
1413 ssh->pktout.savedpos = ssh->pktout.length;
7cca0d81 1414}
51470298 1415static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
32874aea 1416{
51470298 1417 ssh2_pkt_adddata(ssh, data, strlen(data));
1418 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1419 ssh->pktout.length - ssh->pktout.savedpos);
7cca0d81 1420}
51470298 1421static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
32874aea 1422{
51470298 1423 ssh2_pkt_adddata(ssh, data, len);
1424 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1425 ssh->pktout.length - ssh->pktout.savedpos);
7cca0d81 1426}
51470298 1427static void ssh2_pkt_addstring(Ssh ssh, char *data)
32874aea 1428{
51470298 1429 ssh2_pkt_addstring_start(ssh);
1430 ssh2_pkt_addstring_str(ssh, data);
7cca0d81 1431}
32874aea 1432static char *ssh2_mpint_fmt(Bignum b, int *len)
1433{
7cca0d81 1434 unsigned char *p;
32874aea 1435 int i, n = (bignum_bitcount(b) + 7) / 8;
3709bfe9 1436 p = smalloc(n + 1);
7cca0d81 1437 if (!p)
32874aea 1438 fatalbox("out of memory");
7cca0d81 1439 p[0] = 0;
3709bfe9 1440 for (i = 1; i <= n; i++)
32874aea 1441 p[i] = bignum_byte(b, n - i);
7cca0d81 1442 i = 0;
32874aea 1443 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1444 i++;
1445 memmove(p, p + i, n + 1 - i);
1446 *len = n + 1 - i;
7cca0d81 1447 return p;
1448}
51470298 1449static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
32874aea 1450{
7cca0d81 1451 unsigned char *p;
1452 int len;
1453 p = ssh2_mpint_fmt(b, &len);
51470298 1454 ssh2_pkt_addstring_start(ssh);
1455 ssh2_pkt_addstring_data(ssh, p, len);
dcbde236 1456 sfree(p);
7cca0d81 1457}
b185170a 1458
1459/*
1460 * Construct an SSH2 final-form packet: compress it, encrypt it,
1461 * put the MAC on it. Final packet, ready to be sent, is stored in
51470298 1462 * ssh->pktout.data. Total length is returned.
b185170a 1463 */
51470298 1464static int ssh2_pkt_construct(Ssh ssh)
32874aea 1465{
7cca0d81 1466 int cipherblk, maclen, padding, i;
7cca0d81 1467
a8327734 1468 if (ssh->logctx)
1469 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1470 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1471 ssh->pktout.data + 6, ssh->pktout.length - 6);
00db133f 1472
7cca0d81 1473 /*
4ba9b64b 1474 * Compress packet payload.
1475 */
4ba9b64b 1476 {
1477 unsigned char *newpayload;
1478 int newlen;
51470298 1479 if (ssh->cscomp &&
5366aed8 1480 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1481 ssh->pktout.length - 5,
51470298 1482 &newpayload, &newlen)) {
1483 ssh->pktout.length = 5;
1484 ssh2_pkt_adddata(ssh, newpayload, newlen);
dcbde236 1485 sfree(newpayload);
4ba9b64b 1486 }
1487 }
1488
1489 /*
7cca0d81 1490 * Add padding. At least four bytes, and must also bring total
1491 * length (minus MAC) up to a multiple of the block size.
1492 */
51470298 1493 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
32874aea 1494 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
7cca0d81 1495 padding = 4;
32874aea 1496 padding +=
51470298 1497 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1498 maclen = ssh->csmac ? ssh->csmac->len : 0;
1499 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1500 ssh->pktout.data[4] = padding;
7cca0d81 1501 for (i = 0; i < padding; i++)
51470298 1502 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1503 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1504 if (ssh->csmac)
e0e1a00d 1505 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1506 ssh->pktout.length + padding,
51470298 1507 ssh->v2_outgoing_sequence);
1508 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1509
1510 if (ssh->cscipher)
371e569c 1511 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1512 ssh->pktout.data, ssh->pktout.length + padding);
51470298 1513
1514 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1515 return ssh->pktout.length + padding + maclen;
b185170a 1516}
1517
1518/*
1519 * Construct and send an SSH2 packet immediately.
1520 */
51470298 1521static void ssh2_pkt_send(Ssh ssh)
32874aea 1522{
5471d09a 1523 int len;
1524 int backlog;
51470298 1525 len = ssh2_pkt_construct(ssh);
1526 backlog = sk_write(ssh->s, ssh->pktout.data, len);
5471d09a 1527 if (backlog > SSH_MAX_BACKLOG)
51470298 1528 ssh_throttle_all(ssh, 1, backlog);
b185170a 1529}
1530
1531/*
1532 * Construct an SSH2 packet and add it to a deferred data block.
1533 * Useful for sending multiple packets in a single sk_write() call,
1534 * to prevent a traffic-analysing listener from being able to work
1535 * out the length of any particular packet (such as the password
1536 * packet).
1537 *
1538 * Note that because SSH2 sequence-numbers its packets, this can
1539 * NOT be used as an m4-style `defer' allowing packets to be
1540 * constructed in one order and sent in another.
1541 */
51470298 1542static void ssh2_pkt_defer(Ssh ssh)
32874aea 1543{
51470298 1544 int len = ssh2_pkt_construct(ssh);
1545 if (ssh->deferred_len + len > ssh->deferred_size) {
1546 ssh->deferred_size = ssh->deferred_len + len + 128;
1547 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1548 ssh->deferred_size);
b185170a 1549 }
51470298 1550 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1551 ssh->deferred_len += len;
b185170a 1552}
1553
1554/*
1555 * Send the whole deferred data block constructed by
39065bed 1556 * ssh2_pkt_defer() or SSH1's defer_packet().
b185170a 1557 */
51470298 1558static void ssh_pkt_defersend(Ssh ssh)
32874aea 1559{
5471d09a 1560 int backlog;
51470298 1561 backlog = sk_write(ssh->s, ssh->deferred_send_data, ssh->deferred_len);
1562 ssh->deferred_len = ssh->deferred_size = 0;
1563 sfree(ssh->deferred_send_data);
1564 ssh->deferred_send_data = NULL;
5471d09a 1565 if (backlog > SSH_MAX_BACKLOG)
51470298 1566 ssh_throttle_all(ssh, 1, backlog);
7cca0d81 1567}
1568
1569#if 0
32874aea 1570void bndebug(char *string, Bignum b)
1571{
7cca0d81 1572 unsigned char *p;
1573 int i, len;
1574 p = ssh2_mpint_fmt(b, &len);
1575 debug(("%s", string));
1576 for (i = 0; i < len; i++)
32874aea 1577 debug((" %02x", p[i]));
765c4200 1578 debug(("\n"));
dcbde236 1579 sfree(p);
7cca0d81 1580}
1581#endif
1582
32874aea 1583static void sha_mpint(SHA_State * s, Bignum b)
1584{
7cca0d81 1585 unsigned char *p;
1586 int len;
1587 p = ssh2_mpint_fmt(b, &len);
1588 sha_string(s, p, len);
dcbde236 1589 sfree(p);
7cca0d81 1590}
1591
1592/*
1593 * SSH2 packet decode functions.
1594 */
51470298 1595static unsigned long ssh2_pkt_getuint32(Ssh ssh)
32874aea 1596{
7cca0d81 1597 unsigned long value;
51470298 1598 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
32874aea 1599 return 0; /* arrgh, no way to decline (FIXME?) */
51470298 1600 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1601 ssh->pktin.savedpos += 4;
7cca0d81 1602 return value;
1603}
51470298 1604static int ssh2_pkt_getbool(Ssh ssh)
32874aea 1605{
65a22376 1606 unsigned long value;
51470298 1607 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
32874aea 1608 return 0; /* arrgh, no way to decline (FIXME?) */
51470298 1609 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1610 ssh->pktin.savedpos++;
65a22376 1611 return value;
1612}
51470298 1613static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
32874aea 1614{
7cca0d81 1615 *p = NULL;
45068b27 1616 *length = 0;
51470298 1617 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
32874aea 1618 return;
51470298 1619 *length = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1620 ssh->pktin.savedpos += 4;
1621 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
32874aea 1622 return;
51470298 1623 *p = ssh->pktin.data + ssh->pktin.savedpos;
1624 ssh->pktin.savedpos += *length;
7cca0d81 1625}
51470298 1626static Bignum ssh2_pkt_getmp(Ssh ssh)
32874aea 1627{
7cca0d81 1628 char *p;
3709bfe9 1629 int length;
7cca0d81 1630 Bignum b;
1631
51470298 1632 ssh2_pkt_getstring(ssh, &p, &length);
7cca0d81 1633 if (!p)
32874aea 1634 return NULL;
8d5de777 1635 if (p[0] & 0x80) {
a8327734 1636 bombout((ssh,"internal error: Can't handle negative mpints"));
32874aea 1637 return NULL;
8d5de777 1638 }
3709bfe9 1639 b = bignum_from_bytes(p, length);
7cca0d81 1640 return b;
1641}
1642
7d503c31 1643/*
1dd353b5 1644 * Helper function to add an SSH2 signature blob to a packet.
1645 * Expects to be shown the public key blob as well as the signature
1646 * blob. Normally works just like ssh2_pkt_addstring, but will
1647 * fiddle with the signature packet if necessary for
1648 * BUG_SSH2_RSA_PADDING.
1649 */
51470298 1650static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1dd353b5 1651 void *sigblob_v, int sigblob_len)
1652{
1653 unsigned char *pkblob = (unsigned char *)pkblob_v;
1654 unsigned char *sigblob = (unsigned char *)sigblob_v;
1655
1656 /* dmemdump(pkblob, pkblob_len); */
1657 /* dmemdump(sigblob, sigblob_len); */
1658
1659 /*
1660 * See if this is in fact an ssh-rsa signature and a buggy
1661 * server; otherwise we can just do this the easy way.
1662 */
51470298 1663 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1dd353b5 1664 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1665 int pos, len, siglen;
1666
1667 /*
1668 * Find the byte length of the modulus.
1669 */
1670
1671 pos = 4+7; /* skip over "ssh-rsa" */
1672 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1673 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1674 pos += 4; /* find modulus itself */
1675 while (len > 0 && pkblob[pos] == 0)
1676 len--, pos++;
1677 /* debug(("modulus length is %d\n", len)); */
1678
1679 /*
1680 * Now find the signature integer.
1681 */
1682 pos = 4+7; /* skip over "ssh-rsa" */
1683 siglen = GET_32BIT(sigblob+pos);
1684 /* debug(("signature length is %d\n", siglen)); */
1685
1686 if (len != siglen) {
1687 unsigned char newlen[4];
51470298 1688 ssh2_pkt_addstring_start(ssh);
1689 ssh2_pkt_addstring_data(ssh, sigblob, pos);
1dd353b5 1690 /* dmemdump(sigblob, pos); */
1691 pos += 4; /* point to start of actual sig */
1692 PUT_32BIT(newlen, len);
51470298 1693 ssh2_pkt_addstring_data(ssh, newlen, 4);
1dd353b5 1694 /* dmemdump(newlen, 4); */
1695 newlen[0] = 0;
1696 while (len-- > siglen) {
51470298 1697 ssh2_pkt_addstring_data(ssh, newlen, 1);
1dd353b5 1698 /* dmemdump(newlen, 1); */
1699 }
51470298 1700 ssh2_pkt_addstring_data(ssh, sigblob+pos, siglen);
1dd353b5 1701 /* dmemdump(sigblob+pos, siglen); */
1702 return;
1703 }
1704
1705 /* Otherwise fall through and do it the easy way. */
1706 }
1707
51470298 1708 ssh2_pkt_addstring_start(ssh);
1709 ssh2_pkt_addstring_data(ssh, sigblob, sigblob_len);
1dd353b5 1710}
1711
1712/*
7d503c31 1713 * Examine the remote side's version string and compare it against
1714 * a list of known buggy implementations.
1715 */
51470298 1716static void ssh_detect_bugs(Ssh ssh, char *vstring)
32874aea 1717{
1718 char *imp; /* pointer to implementation part */
7d503c31 1719 imp = vstring;
1720 imp += strcspn(imp, "-");
bd358db1 1721 if (*imp) imp++;
7d503c31 1722 imp += strcspn(imp, "-");
bd358db1 1723 if (*imp) imp++;
7d503c31 1724
51470298 1725 ssh->remote_bugs = 0;
7d503c31 1726
2c9c6388 1727 if (cfg.sshbug_ignore1 == BUG_ON ||
1728 (cfg.sshbug_ignore1 == BUG_AUTO &&
1729 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1730 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1731 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
32874aea 1732 /*
1733 * These versions don't support SSH1_MSG_IGNORE, so we have
1734 * to use a different defence against password length
1735 * sniffing.
1736 */
51470298 1737 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
32874aea 1738 logevent("We believe remote version has SSH1 ignore bug");
7d503c31 1739 }
1740
2c9c6388 1741 if (cfg.sshbug_plainpw1 == BUG_ON ||
1742 (cfg.sshbug_plainpw1 == BUG_AUTO &&
1743 (!strcmp(imp, "Cisco-1.25")))) {
bd358db1 1744 /*
1745 * These versions need a plain password sent; they can't
1746 * handle having a null and a random length of data after
1747 * the password.
1748 */
51470298 1749 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
bd358db1 1750 logevent("We believe remote version needs a plain SSH1 password");
1751 }
1752
2c9c6388 1753 if (cfg.sshbug_rsa1 == BUG_ON ||
1754 (cfg.sshbug_rsa1 == BUG_AUTO &&
1755 (!strcmp(imp, "Cisco-1.25")))) {
0df73905 1756 /*
1757 * These versions apparently have no clue whatever about
1758 * RSA authentication and will panic and die if they see
1759 * an AUTH_RSA message.
1760 */
51470298 1761 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
0df73905 1762 logevent("We believe remote version can't handle RSA authentication");
1763 }
1764
2c9c6388 1765 if (cfg.sshbug_hmac2 == BUG_ON ||
1766 (cfg.sshbug_hmac2 == BUG_AUTO &&
1767 (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
1768 !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
1769 !strncmp(imp, "2.1 ", 4)))) {
32874aea 1770 /*
1771 * These versions have the HMAC bug.
1772 */
51470298 1773 ssh->remote_bugs |= BUG_SSH2_HMAC;
32874aea 1774 logevent("We believe remote version has SSH2 HMAC bug");
7d503c31 1775 }
1dd353b5 1776
2c9c6388 1777 if (cfg.sshbug_derivekey2 == BUG_ON ||
1778 (cfg.sshbug_derivekey2 == BUG_AUTO &&
1779 (!strncmp(imp, "2.0.", 4)))) {
088bde77 1780 /*
1781 * These versions have the key-derivation bug (failing to
1782 * include the literal shared secret in the hashes that
1783 * generate the keys).
1784 */
51470298 1785 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
088bde77 1786 logevent("We believe remote version has SSH2 key-derivation bug");
1787 }
1788
2c9c6388 1789 if (cfg.sshbug_rsapad2 == BUG_ON ||
1790 (cfg.sshbug_rsapad2 == BUG_AUTO &&
1791 ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') ||
1792 (!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')))){
1dd353b5 1793 /*
1794 * These versions have the SSH2 RSA padding bug.
1795 */
51470298 1796 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1dd353b5 1797 logevent("We believe remote version has SSH2 RSA padding bug");
1798 }
8e975795 1799
1800 if (cfg.sshbug_dhgex2 == BUG_ON) {
1801 /*
1802 * These versions have the SSH2 DH GEX bug.
1803 */
51470298 1804 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
8e975795 1805 logevent("We believe remote version has SSH2 DH group exchange bug");
1806 }
7d503c31 1807}
1808
51470298 1809static int do_ssh_init(Ssh ssh, unsigned char c)
32874aea 1810{
51470298 1811 struct do_ssh_init_state {
1812 int vslen;
1813 char version[10];
1814 char *vstring;
1815 int vstrsize;
1816 int i;
1817 int proto1, proto2;
1818 };
1819 crState(do_ssh_init_state);
374330e2 1820
51470298 1821 crBegin(ssh->do_ssh_init_crstate);
8df7a775 1822
1823 /* Search for the string "SSH-" in the input. */
51470298 1824 s->i = 0;
8df7a775 1825 while (1) {
1826 static const int transS[] = { 1, 2, 2, 1 };
1827 static const int transH[] = { 0, 0, 3, 0 };
1828 static const int transminus[] = { 0, 0, 0, -1 };
32874aea 1829 if (c == 'S')
51470298 1830 s->i = transS[s->i];
32874aea 1831 else if (c == 'H')
51470298 1832 s->i = transH[s->i];
32874aea 1833 else if (c == '-')
51470298 1834 s->i = transminus[s->i];
32874aea 1835 else
51470298 1836 s->i = 0;
1837 if (s->i < 0)
8df7a775 1838 break;
1839 crReturn(1); /* get another character */
374330e2 1840 }
8df7a775 1841
51470298 1842 s->vstrsize = 16;
1843 s->vstring = smalloc(s->vstrsize);
1844 strcpy(s->vstring, "SSH-");
1845 s->vslen = 4;
1846 s->i = 0;
374330e2 1847 while (1) {
8df7a775 1848 crReturn(1); /* get another char */
51470298 1849 if (s->vslen >= s->vstrsize - 1) {
1850 s->vstrsize += 16;
1851 s->vstring = srealloc(s->vstring, s->vstrsize);
32874aea 1852 }
51470298 1853 s->vstring[s->vslen++] = c;
1854 if (s->i >= 0) {
374330e2 1855 if (c == '-') {
51470298 1856 s->version[s->i] = '\0';
1857 s->i = -1;
1858 } else if (s->i < sizeof(s->version) - 1)
1859 s->version[s->i++] = c;
32874aea 1860 } else if (c == '\n')
374330e2 1861 break;
1862 }
1863
51470298 1864 ssh->agentfwd_enabled = FALSE;
1865 ssh->rdpkt2_state.incoming_sequence = 0;
960e736a 1866
51470298 1867 s->vstring[s->vslen] = 0;
1868 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1869 {
1870 char *vlog;
1871 vlog = smalloc(20 + s->vslen);
1872 sprintf(vlog, "Server version: %s", s->vstring);
1873 logevent(vlog);
1874 sfree(vlog);
1875 }
1876 ssh_detect_bugs(ssh, s->vstring);
c5e9c988 1877
adf799dd 1878 /*
38d228a2 1879 * Decide which SSH protocol version to support.
adf799dd 1880 */
38d228a2 1881
1882 /* Anything strictly below "2.0" means protocol 1 is supported. */
51470298 1883 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
38d228a2 1884 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
51470298 1885 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
38d228a2 1886
51470298 1887 if (cfg.sshprot == 0 && !s->proto1) {
a8327734 1888 bombout((ssh,"SSH protocol version 1 required by user but not provided by server"));
38d228a2 1889 crReturn(0);
1890 }
51470298 1891 if (cfg.sshprot == 3 && !s->proto2) {
a8327734 1892 bombout((ssh,"SSH protocol version 2 required by user but not provided by server"));
38d228a2 1893 crReturn(0);
1894 }
1895
51470298 1896 if (s->proto2 && (cfg.sshprot >= 2 || !s->proto1)) {
32874aea 1897 /*
38d228a2 1898 * Use v2 protocol.
32874aea 1899 */
1900 char verstring[80], vlog[100];
1901 sprintf(verstring, "SSH-2.0-%s", sshver);
51470298 1902 SHA_Init(&ssh->exhashbase);
32874aea 1903 /*
1904 * Hash our version string and their version string.
1905 */
51470298 1906 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1907 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
32874aea 1908 sprintf(vlog, "We claim version: %s", verstring);
1909 logevent(vlog);
1910 strcat(verstring, "\n");
1911 logevent("Using SSH protocol version 2");
51470298 1912 sk_write(ssh->s, verstring, strlen(verstring));
1913 ssh->protocol = ssh2_protocol;
1914 ssh->version = 2;
1915 ssh->s_rdpkt = ssh2_rdpkt;
e5574168 1916 } else {
32874aea 1917 /*
38d228a2 1918 * Use v1 protocol.
32874aea 1919 */
1920 char verstring[80], vlog[100];
1921 sprintf(verstring, "SSH-%s-%s",
51470298 1922 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
32874aea 1923 sshver);
1924 sprintf(vlog, "We claim version: %s", verstring);
1925 logevent(vlog);
1926 strcat(verstring, "\n");
759712a6 1927
32874aea 1928 logevent("Using SSH protocol version 1");
51470298 1929 sk_write(ssh->s, verstring, strlen(verstring));
1930 ssh->protocol = ssh1_protocol;
1931 ssh->version = 1;
1932 ssh->s_rdpkt = ssh1_rdpkt;
e5574168 1933 }
51470298 1934 ssh->state = SSH_STATE_BEFORE_SIZE;
8df7a775 1935
51470298 1936 sfree(s->vstring);
50526e47 1937
8df7a775 1938 crFinish(0);
1939}
1940
51470298 1941static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
8df7a775 1942{
51470298 1943 crBegin(ssh->ssh_gotdata_crstate);
8df7a775 1944
1945 /*
1946 * To begin with, feed the characters one by one to the
1947 * protocol initialisation / selection function do_ssh_init().
1948 * When that returns 0, we're done with the initial greeting
1949 * exchange and can move on to packet discipline.
1950 */
1951 while (1) {
51470298 1952 int ret; /* need not be kept across crReturn */
8df7a775 1953 if (datalen == 0)
1954 crReturnV; /* more data please */
51470298 1955 ret = do_ssh_init(ssh, *data);
32874aea 1956 data++;
1957 datalen--;
8df7a775 1958 if (ret == 0)
1959 break;
1960 }
1961
1962 /*
1963 * We emerge from that loop when the initial negotiation is
1964 * over and we have selected an s_rdpkt function. Now pass
1965 * everything to s_rdpkt, and then pass the resulting packets
1966 * to the proper protocol handler.
1967 */
1968 if (datalen == 0)
1969 crReturnV;
1970 while (1) {
1971 while (datalen > 0) {
51470298 1972 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
1973 if (ssh->state == SSH_STATE_CLOSED) {
e14d0f19 1974 return;
1975 }
51470298 1976 ssh->protocol(ssh, NULL, 0, 1);
1977 if (ssh->state == SSH_STATE_CLOSED) {
8df7a775 1978 return;
1979 }
1980 }
1981 }
1982 crReturnV;
1983 }
1984 crFinishV;
1985}
1986
32874aea 1987static int ssh_closing(Plug plug, char *error_msg, int error_code,
1988 int calling_back)
1989{
51470298 1990 Ssh ssh = (Ssh) plug;
1991 ssh->state = SSH_STATE_CLOSED;
1992 if (ssh->s) {
1993 sk_close(ssh->s);
1994 ssh->s = NULL;
f3ab576e 1995 }
7e78000d 1996 if (error_msg) {
32874aea 1997 /* A socket error has occurred. */
247308b5 1998 logevent(error_msg);
a8327734 1999 connection_fatal(ssh->frontend, error_msg);
7e78000d 2000 } else {
2001 /* Otherwise, the remote side closed the connection normally. */
8df7a775 2002 }
7e78000d 2003 return 0;
2004}
2005
32874aea 2006static int ssh_receive(Plug plug, int urgent, char *data, int len)
2007{
51470298 2008 Ssh ssh = (Ssh) plug;
2009 ssh_gotdata(ssh, data, len);
2010 if (ssh->state == SSH_STATE_CLOSED) {
2011 if (ssh->s) {
2012 sk_close(ssh->s);
2013 ssh->s = NULL;
32874aea 2014 }
2015 return 0;
3257deae 2016 }
fef97f43 2017 return 1;
374330e2 2018}
2019
5471d09a 2020static void ssh_sent(Plug plug, int bufsize)
2021{
51470298 2022 Ssh ssh = (Ssh) plug;
5471d09a 2023 /*
2024 * If the send backlog on the SSH socket itself clears, we
2025 * should unthrottle the whole world if it was throttled.
2026 */
2027 if (bufsize < SSH_MAX_BACKLOG)
51470298 2028 ssh_throttle_all(ssh, 0, bufsize);
5471d09a 2029}
2030
fb09bf1c 2031/*
8df7a775 2032 * Connect to specified host and port.
2033 * Returns an error message, or NULL on success.
6e1ebb76 2034 * Also places the canonical host name into `realhost'. It must be
2035 * freed by the caller.
8df7a775 2036 */
51470298 2037static char *connect_to_host(Ssh ssh, char *host, int port,
2038 char **realhost, int nodelay)
8df7a775 2039{
51470298 2040 static const struct plug_function_table fn_table = {
7e78000d 2041 ssh_closing,
5471d09a 2042 ssh_receive,
2043 ssh_sent,
2044 NULL
51470298 2045 };
7e78000d 2046
8df7a775 2047 SockAddr addr;
2048 char *err;
8df7a775 2049
51470298 2050 ssh->savedhost = smalloc(1 + strlen(host));
2051 if (!ssh->savedhost)
8df7a775 2052 fatalbox("Out of memory");
51470298 2053 strcpy(ssh->savedhost, host);
8df7a775 2054
2055 if (port < 0)
2056 port = 22; /* default ssh port */
51470298 2057 ssh->savedport = port;
8df7a775 2058
2059 /*
2060 * Try to find host.
2061 */
3ad9d396 2062 {
2063 char buf[200];
2064 sprintf(buf, "Looking up host \"%.170s\"", host);
2065 logevent(buf);
2066 }
8df7a775 2067 addr = sk_namelookup(host, realhost);
32874aea 2068 if ((err = sk_addr_error(addr)))
8df7a775 2069 return err;
2070
8df7a775 2071 /*
2072 * Open socket.
2073 */
3ad9d396 2074 {
2075 char buf[200], addrbuf[100];
2076 sk_getaddr(addr, addrbuf, 100);
2077 sprintf(buf, "Connecting to %.100s port %d", addrbuf, port);
2078 logevent(buf);
2079 }
51470298 2080 ssh->fn = &fn_table;
2081 ssh->s = new_connection(addr, *realhost, port, 0, 1, nodelay, (Plug) ssh);
2082 if ((err = sk_socket_error(ssh->s))) {
2083 ssh->s = NULL;
8df7a775 2084 return err;
67c4ba2e 2085 }
8df7a775 2086
8df7a775 2087 return NULL;
2088}
2089
2090/*
5471d09a 2091 * Throttle or unthrottle the SSH connection.
2092 */
51470298 2093static void ssh1_throttle(Ssh ssh, int adjust)
5471d09a 2094{
51470298 2095 int old_count = ssh->v1_throttle_count;
2096 ssh->v1_throttle_count += adjust;
2097 assert(ssh->v1_throttle_count >= 0);
2098 if (ssh->v1_throttle_count && !old_count) {
2099 sk_set_frozen(ssh->s, 1);
2100 } else if (!ssh->v1_throttle_count && old_count) {
2101 sk_set_frozen(ssh->s, 0);
5471d09a 2102 }
2103}
2104
2105/*
2106 * Throttle or unthrottle _all_ local data streams (for when sends
2107 * on the SSH connection itself back up).
2108 */
51470298 2109static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
5471d09a 2110{
2111 int i;
2112 struct ssh_channel *c;
2113
51470298 2114 if (enable == ssh->throttled_all)
5471d09a 2115 return;
51470298 2116 ssh->throttled_all = enable;
2117 ssh->overall_bufsize = bufsize;
2118 if (!ssh->channels)
5471d09a 2119 return;
51470298 2120 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5471d09a 2121 switch (c->type) {
2122 case CHAN_MAINSESSION:
2123 /*
2124 * This is treated separately, outside the switch.
2125 */
2126 break;
2127 case CHAN_X11:
2128 x11_override_throttle(c->u.x11.s, enable);
2129 break;
2130 case CHAN_AGENT:
2131 /* Agent channels require no buffer management. */
2132 break;
2133 case CHAN_SOCKDATA:
2134 pfd_override_throttle(c->u.x11.s, enable);
2135 break;
2136 }
2137 }
2138}
2139
2140/*
51470298 2141 * Username and password input, abstracted off into routines
2142 * reusable in several places - even between SSH1 and SSH2.
0405e71f 2143 */
0405e71f 2144
2145/* Set up a username or password input loop on a given buffer. */
51470298 2146void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
0405e71f 2147{
51470298 2148 ssh->userpass_input_buffer = buffer;
2149 ssh->userpass_input_buflen = buflen;
2150 ssh->userpass_input_bufpos = 0;
2151 ssh->userpass_input_echo = echo;
0405e71f 2152}
2153
2154/*
2155 * Process some terminal data in the course of username/password
2156 * input. Returns >0 for success (line of input returned in
2157 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2158 * for inconclusive (keep waiting for more input please).
2159 */
51470298 2160int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
0405e71f 2161{
2162 char c;
2163
2164 while (inlen--) {
2165 switch (c = *in++) {
2166 case 10:
2167 case 13:
51470298 2168 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2169 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
0405e71f 2170 return +1;
2171 break;
2172 case 8:
2173 case 127:
51470298 2174 if (ssh->userpass_input_bufpos > 0) {
2175 if (ssh->userpass_input_echo)
2176 c_write_str(ssh, "\b \b");
2177 ssh->userpass_input_bufpos--;
0405e71f 2178 }
2179 break;
2180 case 21:
2181 case 27:
51470298 2182 while (ssh->userpass_input_bufpos > 0) {
2183 if (ssh->userpass_input_echo)
2184 c_write_str(ssh, "\b \b");
2185 ssh->userpass_input_bufpos--;
0405e71f 2186 }
2187 break;
2188 case 3:
2189 case 4:
2190 return -1;
2191 break;
2192 default:
2193 if (((c >= ' ' && c <= '~') ||
2194 ((unsigned char) c >= 160))
51470298 2195 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2196 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2197 if (ssh->userpass_input_echo)
2198 c_write(ssh, &c, 1);
0405e71f 2199 }
2200 break;
2201 }
2202 }
2203 return 0;
2204}
2205
2206/*
fb09bf1c 2207 * Handle the key exchange and user authentication phases.
2208 */
51470298 2209static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
fb09bf1c 2210{
2d466ffd 2211 int i, j;
374330e2 2212 unsigned char cookie[8];
2213 struct RSAKey servkey, hostkey;
2214 struct MD5Context md5c;
51470298 2215 struct do_ssh1_login_state {
2216 int len;
2217 unsigned char *rsabuf, *keystr1, *keystr2;
2218 unsigned long supported_ciphers_mask, supported_auths_mask;
2219 int tried_publickey, tried_agent;
2220 int tis_auth_refused, ccard_auth_refused;
2221 unsigned char session_id[16];
2222 int cipher_type;
2223 char username[100];
2224 void *publickey_blob;
2225 int publickey_bloblen;
2226 char password[100];
2227 char prompt[200];
2228 int pos;
2229 char c;
2230 int pwpkt_type;
2231 unsigned char request[5], *response, *p;
2232 int responselen;
2233 int keyi, nkeys;
2234 int authed;
2235 struct RSAKey key;
2236 Bignum challenge;
2237 char *commentp;
2238 int commentlen;
2239 };
2240 crState(do_ssh1_login_state);
2241
2242 crBegin(ssh->do_ssh1_login_crstate);
374330e2 2243
32874aea 2244 if (!ispkt)
2245 crWaitUntil(ispkt);
374330e2 2246
51470298 2247 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
a8327734 2248 bombout((ssh,"Public key packet not received"));
32874aea 2249 crReturn(0);
8d5de777 2250 }
374330e2 2251
c5e9c988 2252 logevent("Received public keys");
374330e2 2253
51470298 2254 memcpy(cookie, ssh->pktin.body, 8);
374330e2 2255
51470298 2256 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2257 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
374330e2 2258
c5e9c988 2259 /*
1c2a93c4 2260 * Log the host key fingerprint.
c5e9c988 2261 */
c5e9c988 2262 {
2263 char logmsg[80];
1c2a93c4 2264 logevent("Host key fingerprint is:");
c5e9c988 2265 strcpy(logmsg, " ");
32874aea 2266 hostkey.comment = NULL;
2267 rsa_fingerprint(logmsg + strlen(logmsg),
2268 sizeof(logmsg) - strlen(logmsg), &hostkey);
c5e9c988 2269 logevent(logmsg);
2270 }
2271
51470298 2272 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2273 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2274 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
bea1ef5f 2275
51470298 2276 ssh->v1_local_protoflags =
2277 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2278 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
b96dc54c 2279
c5e9c988 2280 MD5Init(&md5c);
51470298 2281 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2282 MD5Update(&md5c, s->keystr1, servkey.bytes);
2283 MD5Update(&md5c, ssh->pktin.body, 8);
2284 MD5Final(s->session_id, &md5c);
374330e2 2285
32874aea 2286 for (i = 0; i < 32; i++)
51470298 2287 ssh->session_key[i] = random_byte();
374330e2 2288
51470298 2289 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
374330e2 2290
51470298 2291 s->rsabuf = smalloc(s->len);
2292 if (!s->rsabuf)
374330e2 2293 fatalbox("Out of memory");
2294
89ee5268 2295 /*
2296 * Verify the host key.
2297 */
2298 {
32874aea 2299 /*
2300 * First format the key into a string.
2301 */
2302 int len = rsastr_len(&hostkey);
2303 char fingerprint[100];
2304 char *keystr = smalloc(len);
2305 if (!keystr)
2306 fatalbox("Out of memory");
2307 rsastr_fmt(keystr, &hostkey);
2308 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
a8327734 2309 verify_ssh_host_key(ssh->frontend,
2310 ssh->savedhost, ssh->savedport, "rsa", keystr,
32874aea 2311 fingerprint);
2312 sfree(keystr);
2313 }
2314
2315 for (i = 0; i < 32; i++) {
51470298 2316 s->rsabuf[i] = ssh->session_key[i];
374330e2 2317 if (i < 16)
51470298 2318 s->rsabuf[i] ^= s->session_id[i];
374330e2 2319 }
2320
2321 if (hostkey.bytes > servkey.bytes) {
51470298 2322 rsaencrypt(s->rsabuf, 32, &servkey);
2323 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
374330e2 2324 } else {
51470298 2325 rsaencrypt(s->rsabuf, 32, &hostkey);
2326 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
374330e2 2327 }
2328
c5e9c988 2329 logevent("Encrypted session key");
2330
ca20bfcf 2331 {
2332 int cipher_chosen = 0, warn = 0;
2333 char *cipher_string = NULL;
51470298 2334 int i;
ca20bfcf 2335 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2336 int next_cipher = cfg.ssh_cipherlist[i];
2337 if (next_cipher == CIPHER_WARN) {
2338 /* If/when we choose a cipher, warn about it */
2339 warn = 1;
2340 } else if (next_cipher == CIPHER_AES) {
2341 /* XXX Probably don't need to mention this. */
2342 logevent("AES not supported in SSH1, skipping");
2343 } else {
2344 switch (next_cipher) {
51470298 2345 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
ca20bfcf 2346 cipher_string = "3DES"; break;
51470298 2347 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
ca20bfcf 2348 cipher_string = "Blowfish"; break;
51470298 2349 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
ca20bfcf 2350 cipher_string = "single-DES"; break;
2351 }
51470298 2352 if (s->supported_ciphers_mask & (1 << s->cipher_type))
ca20bfcf 2353 cipher_chosen = 1;
2354 }
2355 }
2356 if (!cipher_chosen) {
51470298 2357 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
a8327734 2358 bombout((ssh,"Server violates SSH 1 protocol by not "
ca20bfcf 2359 "supporting 3DES encryption"));
2360 else
2361 /* shouldn't happen */
a8327734 2362 bombout((ssh,"No supported ciphers found"));
a99a05c0 2363 crReturn(0);
2364 }
ca20bfcf 2365
2366 /* Warn about chosen cipher if necessary. */
2367 if (warn)
a8327734 2368 askcipher(ssh->frontend, cipher_string, 0);
bea1ef5f 2369 }
ca20bfcf 2370
51470298 2371 switch (s->cipher_type) {
32874aea 2372 case SSH_CIPHER_3DES:
2373 logevent("Using 3DES encryption");
2374 break;
2375 case SSH_CIPHER_DES:
2376 logevent("Using single-DES encryption");
2377 break;
2378 case SSH_CIPHER_BLOWFISH:
2379 logevent("Using Blowfish encryption");
2380 break;
c5e9c988 2381 }
bea1ef5f 2382
51470298 2383 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2384 PKT_CHAR, s->cipher_type,
32874aea 2385 PKT_DATA, cookie, 8,
51470298 2386 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2387 PKT_DATA, s->rsabuf, s->len,
2388 PKT_INT, ssh->v1_local_protoflags, PKT_END);
fb09bf1c 2389
c5e9c988 2390 logevent("Trying to enable encryption...");
374330e2 2391
51470298 2392 sfree(s->rsabuf);
374330e2 2393
51470298 2394 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2395 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2396 &ssh_3des);
371e569c 2397 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2398 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2399 {
2400 char buf[256];
2401 sprintf(buf, "Initialised %.200s encryption", ssh->cipher->text_name);
2402 logevent(buf);
2403 }
374330e2 2404
0183b242 2405 ssh->crcda_ctx = crcda_make_context();
2406 logevent("Installing CRC compensation attack detector");
2407
fb09bf1c 2408 crWaitUntil(ispkt);
374330e2 2409
51470298 2410 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
a8327734 2411 bombout((ssh,"Encryption not successfully enabled"));
32874aea 2412 crReturn(0);
8d5de777 2413 }
374330e2 2414
c5e9c988 2415 logevent("Successfully started encryption");
2416
374330e2 2417 fflush(stdout);
2418 {
67779be7 2419 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
c0a81592 2420 if (ssh_get_line && !ssh_getline_pw_only) {
32874aea 2421 if (!ssh_get_line("login as: ",
51470298 2422 s->username, sizeof(s->username), FALSE)) {
32874aea 2423 /*
2424 * get_line failed to get a username.
2425 * Terminate.
2426 */
2427 logevent("No username provided. Abandoning session.");
51470298 2428 ssh->state = SSH_STATE_CLOSED;
32874aea 2429 crReturn(1);
2430 }
2431 } else {
51470298 2432 int ret; /* need not be kept over crReturn */
2433 c_write_str(ssh, "login as: ");
2434 ssh->send_ok = 1;
0405e71f 2435
51470298 2436 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
0405e71f 2437 do {
32874aea 2438 crWaitUntil(!ispkt);
51470298 2439 ret = process_userpass_input(ssh, in, inlen);
0405e71f 2440 } while (ret == 0);
2441 if (ret < 0)
2442 cleanup_exit(0);
51470298 2443 c_write_str(ssh, "\r\n");
32874aea 2444 }
2445 } else {
51470298 2446 strncpy(s->username, cfg.username, sizeof(s->username));
2447 s->username[sizeof(s->username)-1] = '\0';
374330e2 2448 }
fb09bf1c 2449
51470298 2450 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
c5e9c988 2451 {
51470298 2452 char userlog[22 + sizeof(s->username)];
2453 sprintf(userlog, "Sent username \"%s\"", s->username);
c5e9c988 2454 logevent(userlog);
32874aea 2455 if (flags & FLAG_INTERACTIVE &&
2456 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
3c8e959b 2457 strcat(userlog, "\r\n");
51470298 2458 c_write_str(ssh, userlog);
3c8e959b 2459 }
c5e9c988 2460 }
374330e2 2461 }
2462
fb09bf1c 2463 crWaitUntil(ispkt);
374330e2 2464
51470298 2465 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
0df73905 2466 /* We must not attempt PK auth. Pretend we've already tried it. */
51470298 2467 s->tried_publickey = s->tried_agent = 1;
0df73905 2468 } else {
51470298 2469 s->tried_publickey = s->tried_agent = 0;
0df73905 2470 }
51470298 2471 s->tis_auth_refused = s->ccard_auth_refused = 0;
396778f1 2472 /* Load the public half of cfg.keyfile so we notice if it's in Pageant */
2473 if (*cfg.keyfile) {
51470298 2474 if (!rsakey_pubblob(cfg.keyfile,
2475 &s->publickey_blob, &s->publickey_bloblen))
2476 s->publickey_blob = NULL;
396778f1 2477 } else
51470298 2478 s->publickey_blob = NULL;
7cca0d81 2479
51470298 2480 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2481 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
614a20a0 2482
51470298 2483 if (agent_exists() && !s->tried_agent) {
32874aea 2484 /*
2485 * Attempt RSA authentication using Pageant.
2486 */
32874aea 2487 void *r;
2488
51470298 2489 s->authed = FALSE;
2490 s->tried_agent = 1;
32874aea 2491 logevent("Pageant is running. Requesting keys.");
2492
2493 /* Request the keys held by the agent. */
51470298 2494 PUT_32BIT(s->request, 1);
2495 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2496 agent_query(s->request, 5, &r, &s->responselen);
2497 s->response = (unsigned char *) r;
2498 if (s->response && s->responselen >= 5 &&
2499 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2500 s->p = s->response + 5;
2501 s->nkeys = GET_32BIT(s->p);
2502 s->p += 4;
32874aea 2503 {
2504 char buf[64];
51470298 2505 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
32874aea 2506 logevent(buf);
2507 }
51470298 2508 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
32874aea 2509 {
2510 char buf[64];
51470298 2511 sprintf(buf, "Trying Pageant key #%d", s->keyi);
32874aea 2512 logevent(buf);
2513 }
51470298 2514 if (s->publickey_blob &&
2515 !memcmp(s->p, s->publickey_blob,
2516 s->publickey_bloblen)) {
396778f1 2517 logevent("This key matches configured key file");
51470298 2518 s->tried_publickey = 1;
396778f1 2519 }
51470298 2520 s->p += 4;
2521 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2522 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2523 s->commentlen = GET_32BIT(s->p);
2524 s->p += 4;
2525 s->commentp = s->p;
2526 s->p += s->commentlen;
2527 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2528 PKT_BIGNUM, s->key.modulus, PKT_END);
32874aea 2529 crWaitUntil(ispkt);
51470298 2530 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
32874aea 2531 logevent("Key refused");
2532 continue;
2533 }
2534 logevent("Received RSA challenge");
51470298 2535 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
32874aea 2536 {
2537 char *agentreq, *q, *ret;
2d466ffd 2538 void *vret;
32874aea 2539 int len, retlen;
2540 len = 1 + 4; /* message type, bit count */
51470298 2541 len += ssh1_bignum_length(s->key.exponent);
2542 len += ssh1_bignum_length(s->key.modulus);
2543 len += ssh1_bignum_length(s->challenge);
32874aea 2544 len += 16; /* session id */
2545 len += 4; /* response format */
2546 agentreq = smalloc(4 + len);
2547 PUT_32BIT(agentreq, len);
2548 q = agentreq + 4;
2549 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
51470298 2550 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
32874aea 2551 q += 4;
51470298 2552 q += ssh1_write_bignum(q, s->key.exponent);
2553 q += ssh1_write_bignum(q, s->key.modulus);
2554 q += ssh1_write_bignum(q, s->challenge);
2555 memcpy(q, s->session_id, 16);
32874aea 2556 q += 16;
2557 PUT_32BIT(q, 1); /* response format */
2d466ffd 2558 agent_query(agentreq, len + 4, &vret, &retlen);
2559 ret = vret;
32874aea 2560 sfree(agentreq);
2561 if (ret) {
2562 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2563 logevent("Sending Pageant's response");
51470298 2564 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
32874aea 2565 PKT_DATA, ret + 5, 16,
2566 PKT_END);
2567 sfree(ret);
2568 crWaitUntil(ispkt);
51470298 2569 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
32874aea 2570 logevent
2571 ("Pageant's response accepted");
2572 if (flags & FLAG_VERBOSE) {
51470298 2573 c_write_str(ssh, "Authenticated using"
2574 " RSA key \"");
2575 c_write(ssh, s->commentp,
2576 s->commentlen);
2577 c_write_str(ssh, "\" from agent\r\n");
32874aea 2578 }
51470298 2579 s->authed = TRUE;
32874aea 2580 } else
2581 logevent
2582 ("Pageant's response not accepted");
2583 } else {
2584 logevent
2585 ("Pageant failed to answer challenge");
2586 sfree(ret);
2587 }
2588 } else {
2589 logevent("No reply received from Pageant");
2590 }
2591 }
51470298 2592 freebn(s->key.exponent);
2593 freebn(s->key.modulus);
2594 freebn(s->challenge);
2595 if (s->authed)
32874aea 2596 break;
2597 }
2598 }
51470298 2599 if (s->authed)
32874aea 2600 break;
2601 }
51470298 2602 if (*cfg.keyfile && !s->tried_publickey)
2603 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
32874aea 2604
614a20a0 2605 if (cfg.try_tis_auth &&
51470298 2606 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2607 !s->tis_auth_refused) {
2608 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
32874aea 2609 logevent("Requested TIS authentication");
51470298 2610 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
32874aea 2611 crWaitUntil(ispkt);
51470298 2612 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
32874aea 2613 logevent("TIS authentication declined");
2614 if (flags & FLAG_INTERACTIVE)
51470298 2615 c_write_str(ssh, "TIS authentication refused.\r\n");
2616 s->tis_auth_refused = 1;
614a20a0 2617 continue;
32874aea 2618 } else {
51470298 2619 int challengelen = GET_32BIT(ssh->pktin.body);
32874aea 2620 logevent("Received TIS challenge");
51470298 2621 if (challengelen > sizeof(s->prompt) - 1)
2622 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2623 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
614a20a0 2624 /* Prompt heuristic comes from OpenSSH */
51470298 2625 strncpy(s->prompt + challengelen,
2626 memchr(s->prompt, '\n', challengelen) ?
614a20a0 2627 "": "\r\nResponse: ",
51470298 2628 (sizeof s->prompt) - challengelen);
2629 s->prompt[(sizeof s->prompt) - 1] = '\0';
32874aea 2630 }
2631 }
614a20a0 2632 if (cfg.try_tis_auth &&
51470298 2633 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2634 !s->ccard_auth_refused) {
2635 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
32874aea 2636 logevent("Requested CryptoCard authentication");
51470298 2637 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
32874aea 2638 crWaitUntil(ispkt);
51470298 2639 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
32874aea 2640 logevent("CryptoCard authentication declined");
51470298 2641 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2642 s->ccard_auth_refused = 1;
614a20a0 2643 continue;
32874aea 2644 } else {
51470298 2645 int challengelen = GET_32BIT(ssh->pktin.body);
32874aea 2646 logevent("Received CryptoCard challenge");
51470298 2647 if (challengelen > sizeof(s->prompt) - 1)
2648 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2649 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2650 strncpy(s->prompt + challengelen,
2651 memchr(s->prompt, '\n', challengelen) ?
614a20a0 2652 "" : "\r\nResponse: ",
51470298 2653 sizeof(s->prompt) - challengelen);
2654 s->prompt[sizeof(s->prompt) - 1] = '\0';
32874aea 2655 }
2656 }
51470298 2657 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2658 sprintf(s->prompt, "%.90s@%.90s's password: ",
2659 s->username, ssh->savedhost);
32874aea 2660 }
51470298 2661 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
32874aea 2662 char *comment = NULL;
231ee168 2663 int type;
2664 char msgbuf[256];
32874aea 2665 if (flags & FLAG_VERBOSE)
51470298 2666 c_write_str(ssh, "Trying public key authentication.\r\n");
231ee168 2667 sprintf(msgbuf, "Trying public key \"%.200s\"", cfg.keyfile);
2668 logevent(msgbuf);
2669 type = key_type(cfg.keyfile);
2670 if (type != SSH_KEYTYPE_SSH1) {
2671 sprintf(msgbuf, "Key is of wrong type (%s)",
2672 key_type_to_str(type));
2673 logevent(msgbuf);
51470298 2674 c_write_str(ssh, msgbuf);
2675 c_write_str(ssh, "\r\n");
2676 s->tried_publickey = 1;
231ee168 2677 continue;
2678 }
32874aea 2679 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
2680 if (flags & FLAG_VERBOSE)
51470298 2681 c_write_str(ssh, "No passphrase required.\r\n");
32874aea 2682 goto tryauth;
2683 }
51470298 2684 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
32874aea 2685 sfree(comment);
2686 }
a52f067e 2687
614a20a0 2688 /*
2689 * Show password prompt, having first obtained it via a TIS
2690 * or CryptoCard exchange if we're doing TIS or CryptoCard
2691 * authentication.
2692 */
fa17a66e 2693 if (ssh_get_line) {
51470298 2694 if (!ssh_get_line(s->prompt, s->password,
2695 sizeof(s->password), TRUE)) {
32874aea 2696 /*
2697 * get_line failed to get a password (for example
2698 * because one was supplied on the command line
2699 * which has already failed to work). Terminate.
2700 */
51470298 2701 send_packet(ssh, SSH1_MSG_DISCONNECT,
2bc6a386 2702 PKT_STR, "No more passwords available to try",
2703 PKT_END);
247308b5 2704 logevent("Unable to authenticate");
a8327734 2705 connection_fatal(ssh->frontend, "Unable to authenticate");
51470298 2706 ssh->state = SSH_STATE_CLOSED;
32874aea 2707 crReturn(1);
2708 }
fb09bf1c 2709 } else {
614a20a0 2710 /* Prompt may have come from server. We've munged it a bit, so
2711 * we know it to be zero-terminated at least once. */
51470298 2712 int ret; /* need not be saved over crReturn */
2713 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2714 s->pos = 0;
0405e71f 2715
51470298 2716 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
0405e71f 2717 do {
32874aea 2718 crWaitUntil(!ispkt);
51470298 2719 ret = process_userpass_input(ssh, in, inlen);
0405e71f 2720 } while (ret == 0);
2721 if (ret < 0)
2722 cleanup_exit(0);
51470298 2723 c_write_str(ssh, "\r\n");
32874aea 2724 }
2725
2726 tryauth:
51470298 2727 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
32874aea 2728 /*
2729 * Try public key authentication with the specified
2730 * key file.
2731 */
51470298 2732 s->tried_publickey = 1;
2733
2734 {
2735 int ret = loadrsakey(cfg.keyfile, &s->key, s->password);
2736 if (ret == 0) {
2737 c_write_str(ssh, "Couldn't load private key from ");
2738 c_write_str(ssh, cfg.keyfile);
2739 c_write_str(ssh, ".\r\n");
2740 continue; /* go and try password */
2741 }
2742 if (ret == -1) {
2743 c_write_str(ssh, "Wrong passphrase.\r\n");
2744 s->tried_publickey = 0;
2745 continue; /* try again */
2746 }
32874aea 2747 }
2748
2749 /*
2750 * Send a public key attempt.
2751 */
51470298 2752 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2753 PKT_BIGNUM, s->key.modulus, PKT_END);
32874aea 2754
2755 crWaitUntil(ispkt);
51470298 2756 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2757 c_write_str(ssh, "Server refused our public key.\r\n");
32874aea 2758 continue; /* go and try password */
2759 }
51470298 2760 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
a8327734 2761 bombout((ssh,"Bizarre response to offer of public key"));
32874aea 2762 crReturn(0);
2763 }
32874aea 2764
51470298 2765 {
2766 int i;
2767 unsigned char buffer[32];
2768 Bignum challenge, response;
2769
2770 ssh1_read_bignum(ssh->pktin.body, &challenge);
2771 response = rsadecrypt(challenge, &s->key);
2772 freebn(s->key.private_exponent);/* burn the evidence */
32874aea 2773
51470298 2774 for (i = 0; i < 32; i++) {
2775 buffer[i] = bignum_byte(response, 31 - i);
2776 }
2777
2778 MD5Init(&md5c);
2779 MD5Update(&md5c, buffer, 32);
2780 MD5Update(&md5c, s->session_id, 16);
2781 MD5Final(buffer, &md5c);
32874aea 2782
51470298 2783 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2784 PKT_DATA, buffer, 16, PKT_END);
2785
2786 freebn(challenge);
2787 freebn(response);
2788 }
32874aea 2789
2790 crWaitUntil(ispkt);
51470298 2791 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
32874aea 2792 if (flags & FLAG_VERBOSE)
51470298 2793 c_write_str(ssh, "Failed to authenticate with"
2794 " our public key.\r\n");
32874aea 2795 continue; /* go and try password */
51470298 2796 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
a8327734 2797 bombout((ssh,"Bizarre response to RSA authentication response"));
32874aea 2798 crReturn(0);
2799 }
2800
2801 break; /* we're through! */
2802 } else {
51470298 2803 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
32874aea 2804 /*
2805 * Defence against traffic analysis: we send a
2806 * whole bunch of packets containing strings of
2807 * different lengths. One of these strings is the
2808 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2809 * The others are all random data in
2810 * SSH1_MSG_IGNORE packets. This way a passive
2811 * listener can't tell which is the password, and
2812 * hence can't deduce the password length.
2813 *
2814 * Anybody with a password length greater than 16
2815 * bytes is going to have enough entropy in their
2816 * password that a listener won't find it _that_
2817 * much help to know how long it is. So what we'll
2818 * do is:
2819 *
2820 * - if password length < 16, we send 15 packets
2821 * containing string lengths 1 through 15
2822 *
2823 * - otherwise, we let N be the nearest multiple
2824 * of 8 below the password length, and send 8
2825 * packets containing string lengths N through
2826 * N+7. This won't obscure the order of
2827 * magnitude of the password length, but it will
2828 * introduce a bit of extra uncertainty.
2829 *
2830 * A few servers (the old 1.2.18 through 1.2.22)
2831 * can't deal with SSH1_MSG_IGNORE. For these
2832 * servers, we need an alternative defence. We make
2833 * use of the fact that the password is interpreted
2834 * as a C string: so we can append a NUL, then some
2835 * random data.
bd358db1 2836 *
2837 * One server (a Cisco one) can deal with neither
2838 * SSH1_MSG_IGNORE _nor_ a padded password string.
2839 * For this server we are left with no defences
2840 * against password length sniffing.
32874aea 2841 */
51470298 2842 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
b17c8428 2843 /*
2844 * The server can deal with SSH1_MSG_IGNORE, so
2845 * we can use the primary defence.
2846 */
32874aea 2847 int bottom, top, pwlen, i;
2848 char *randomstr;
2849
51470298 2850 pwlen = strlen(s->password);
32874aea 2851 if (pwlen < 16) {
2852 bottom = 0; /* zero length passwords are OK! :-) */
2853 top = 15;
2854 } else {
2855 bottom = pwlen & ~7;
2856 top = bottom + 7;
2857 }
2858
2859 assert(pwlen >= bottom && pwlen <= top);
2860
2861 randomstr = smalloc(top + 1);
2862
2863 for (i = bottom; i <= top; i++) {
2864 if (i == pwlen)
51470298 2865 defer_packet(ssh, s->pwpkt_type,
2866 PKT_STR, s->password, PKT_END);
32874aea 2867 else {
2868 for (j = 0; j < i; j++) {
2869 do {
2870 randomstr[j] = random_byte();
2871 } while (randomstr[j] == '\0');
2872 }
2873 randomstr[i] = '\0';
51470298 2874 defer_packet(ssh, SSH1_MSG_IGNORE,
32874aea 2875 PKT_STR, randomstr, PKT_END);
2876 }
2877 }
bd358db1 2878 logevent("Sending password with camouflage packets");
51470298 2879 ssh_pkt_defersend(ssh);
bd358db1 2880 }
51470298 2881 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
b17c8428 2882 /*
2883 * The server can't deal with SSH1_MSG_IGNORE
2884 * but can deal with padded passwords, so we
2885 * can use the secondary defence.
2886 */
bd358db1 2887 char string[64];
51470298 2888 char *ss;
bd358db1 2889 int len;
2890
51470298 2891 len = strlen(s->password);
bd358db1 2892 if (len < sizeof(string)) {
51470298 2893 ss = string;
2894 strcpy(string, s->password);
bd358db1 2895 len++; /* cover the zero byte */
2896 while (len < sizeof(string)) {
2897 string[len++] = (char) random_byte();
2898 }
2899 } else {
51470298 2900 ss = s->password;
bd358db1 2901 }
2902 logevent("Sending length-padded password");
51470298 2903 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2904 PKT_DATA, ss, len, PKT_END);
bd358db1 2905 } else {
2906 /*
2907 * The server has _both_
2908 * BUG_CHOKES_ON_SSH1_IGNORE and
2909 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2910 * therefore nothing we can do.
2911 */
2912 int len;
51470298 2913 len = strlen(s->password);
bd358db1 2914 logevent("Sending unpadded password");
51470298 2915 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2916 PKT_DATA, s->password, len, PKT_END);
32874aea 2917 }
2918 } else {
51470298 2919 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
32874aea 2920 }
2921 }
c5e9c988 2922 logevent("Sent password");
51470298 2923 memset(s->password, 0, strlen(s->password));
fb09bf1c 2924 crWaitUntil(ispkt);
51470298 2925 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
32874aea 2926 if (flags & FLAG_VERBOSE)
51470298 2927 c_write_str(ssh, "Access denied\r\n");
c5e9c988 2928 logevent("Authentication refused");
51470298 2929 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
a8327734 2930 bombout((ssh,"Strange packet received, type %d", ssh->pktin.type));
32874aea 2931 crReturn(0);
374330e2 2932 }
2933 }
2934
c5e9c988 2935 logevent("Authentication successful");
2936
fb09bf1c 2937 crFinish(1);
2938}
2939
32874aea 2940void sshfwd_close(struct ssh_channel *c)
2941{
51470298 2942 Ssh ssh = c->ssh;
2943
80e48603 2944 if (c && !c->closes) {
4ed34d25 2945 /*
2946 * If the channel's remoteid is -1, we have sent
2947 * CHANNEL_OPEN for this channel, but it hasn't even been
2948 * acknowledged by the server. So we must set a close flag
2949 * on it now, and then when the server acks the channel
2950 * open, we can close it then.
2951 */
36cac739 2952 if (((int)c->remoteid) != -1) {
51470298 2953 if (ssh->version == 1) {
2954 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
4ed34d25 2955 PKT_END);
2956 } else {
51470298 2957 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
2958 ssh2_pkt_adduint32(ssh, c->remoteid);
2959 ssh2_pkt_send(ssh);
4ed34d25 2960 }
32874aea 2961 }
0357890f 2962 c->closes = 1; /* sent MSG_CLOSE */
32874aea 2963 if (c->type == CHAN_X11) {
2964 c->u.x11.s = NULL;
d74d141c 2965 logevent("Forwarded X11 connection terminated");
4ed34d25 2966 } else if (c->type == CHAN_SOCKDATA ||
2967 c->type == CHAN_SOCKDATA_DORMANT) {
d74d141c 2968 c->u.pfd.s = NULL;
2969 logevent("Forwarded port closed");
32874aea 2970 }
2971 }
2972}
2973
5471d09a 2974int sshfwd_write(struct ssh_channel *c, char *buf, int len)
32874aea 2975{
51470298 2976 Ssh ssh = c->ssh;
2977
2978 if (ssh->version == 1) {
2979 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
32874aea 2980 PKT_INT, c->remoteid,
2981 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
5471d09a 2982 /*
2983 * In SSH1 we can return 0 here - implying that forwarded
2984 * connections are never individually throttled - because
2985 * the only circumstance that can cause throttling will be
2986 * the whole SSH connection backing up, in which case
2987 * _everything_ will be throttled as a whole.
2988 */
2989 return 0;
783415f8 2990 } else {
32874aea 2991 ssh2_add_channel_data(c, buf, len);
5471d09a 2992 return ssh2_try_send(c);
2993 }
2994}
2995
2996void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
2997{
51470298 2998 Ssh ssh = c->ssh;
2999
3000 if (ssh->version == 1) {
5471d09a 3001 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3002 c->v.v1.throttling = 0;
51470298 3003 ssh1_throttle(ssh, -1);
5471d09a 3004 }
3005 } else {
3006 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
783415f8 3007 }
9c964e85 3008}
3009
51470298 3010static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
32874aea 3011{
51470298 3012 crBegin(ssh->ssh1_protocol_crstate);
fb09bf1c 3013
3014 random_init();
3015
51470298 3016 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
fb09bf1c 3017 crReturnV;
85ee8208 3018 }
51470298 3019 if (ssh->state == SSH_STATE_CLOSED)
32874aea 3020 crReturnV;
fb09bf1c 3021
979310f1 3022 if (cfg.agentfwd && agent_exists()) {
32874aea 3023 logevent("Requesting agent forwarding");
51470298 3024 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
32874aea 3025 do {
3026 crReturnV;
3027 } while (!ispkt);
51470298 3028 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3029 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
a8327734 3030 bombout((ssh,"Protocol confusion"));
32874aea 3031 crReturnV;
51470298 3032 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
32874aea 3033 logevent("Agent forwarding refused");
3034 } else {
3035 logevent("Agent forwarding enabled");
51470298 3036 ssh->agentfwd_enabled = TRUE;
db7d555c 3037 }
dacbd0e8 3038 }
3039
9c964e85 3040 if (cfg.x11_forward) {
32874aea 3041 char proto[20], data[64];
3042 logevent("Requesting X11 forwarding");
302121de 3043 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3044 data, sizeof(data));
51470298 3045 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3046 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
32874aea 3047 PKT_STR, proto, PKT_STR, data,
3048 PKT_INT, 0, PKT_END);
3049 } else {
51470298 3050 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
32874aea 3051 PKT_STR, proto, PKT_STR, data, PKT_END);
3052 }
3053 do {
3054 crReturnV;
3055 } while (!ispkt);
51470298 3056 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3057 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
a8327734 3058 bombout((ssh,"Protocol confusion"));
32874aea 3059 crReturnV;
51470298 3060 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
32874aea 3061 logevent("X11 forwarding refused");
3062 } else {
3063 logevent("X11 forwarding enabled");
51470298 3064 ssh->X11_fwd_enabled = TRUE;
9c964e85 3065 }
3066 }
3067
d74d141c 3068 {
9bf696b1 3069 char type;
d74d141c 3070 int n;
a4fc0d74 3071 int sport,dport,sserv,dserv;
d74d141c 3072 char sports[256], dports[256], host[256];
3073 char buf[1024];
3074
51470298 3075 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
d74d141c 3076 /* Add port forwardings. */
51470298 3077 ssh->portfwd_strptr = cfg.portfwd;
3078 while (*ssh->portfwd_strptr) {
3079 type = *ssh->portfwd_strptr++;
d74d141c 3080 n = 0;
51470298 3081 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t')
3082 sports[n++] = *ssh->portfwd_strptr++;
d74d141c 3083 sports[n] = 0;
51470298 3084 if (*ssh->portfwd_strptr == '\t')
3085 ssh->portfwd_strptr++;
d74d141c 3086 n = 0;
51470298 3087 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':')
3088 host[n++] = *ssh->portfwd_strptr++;
d74d141c 3089 host[n] = 0;
51470298 3090 if (*ssh->portfwd_strptr == ':')
3091 ssh->portfwd_strptr++;
d74d141c 3092 n = 0;
51470298 3093 while (*ssh->portfwd_strptr)
3094 dports[n++] = *ssh->portfwd_strptr++;
d74d141c 3095 dports[n] = 0;
51470298 3096 ssh->portfwd_strptr++;
d74d141c 3097 dport = atoi(dports);
a4fc0d74 3098 dserv = 0;
3099 if (dport == 0) {
3100 dserv = 1;
68a49acb 3101 dport = net_service_lookup(dports);
3102 if (!dport) {
a4fc0d74 3103 sprintf(buf,
3104 "Service lookup failed for destination port \"%s\"",
3105 dports);
3106 logevent(buf);
3107 }
3108 }
d74d141c 3109 sport = atoi(sports);
a4fc0d74 3110 sserv = 0;
3111 if (sport == 0) {
3112 sserv = 1;
68a49acb 3113 sport = net_service_lookup(sports);
3114 if (!sport) {
a4fc0d74 3115 sprintf(buf,
3116 "Service lookup failed for source port \"%s\"",
3117 sports);
3118 logevent(buf);
3119 }
3120 }
d74d141c 3121 if (sport && dport) {
3122 if (type == 'L') {
6b78788a 3123 pfd_addforward(host, dport, sport, ssh);
a4fc0d74 3124 sprintf(buf, "Local port %.*s%.*s%d%.*s forwarding to"
3125 " %s:%.*s%.*s%d%.*s",
68a49acb 3126 (int)(sserv ? strlen(sports) : 0), sports,
a4fc0d74 3127 sserv, "(", sport, sserv, ")",
3128 host,
68a49acb 3129 (int)(dserv ? strlen(dports) : 0), dports,
a4fc0d74 3130 dserv, "(", dport, dserv, ")");
d74d141c 3131 logevent(buf);
3132 } else {
3133 struct ssh_rportfwd *pf;
3134 pf = smalloc(sizeof(*pf));
bc240b21 3135 strcpy(pf->dhost, host);
3136 pf->dport = dport;
51470298 3137 if (add234(ssh->rportfwds, pf) != pf) {
d74d141c 3138 sprintf(buf,
95bc8819 3139 "Duplicate remote port forwarding to %s:%d",
d74d141c 3140 host, dport);
3141 logevent(buf);
bc240b21 3142 sfree(pf);
d74d141c 3143 } else {
a4fc0d74 3144 sprintf(buf, "Requesting remote port %.*s%.*s%d%.*s"
3145 " forward to %s:%.*s%.*s%d%.*s",
68a49acb 3146 (int)(sserv ? strlen(sports) : 0), sports,
a4fc0d74 3147 sserv, "(", sport, sserv, ")",
3148 host,
68a49acb 3149 (int)(dserv ? strlen(dports) : 0), dports,
a4fc0d74 3150 dserv, "(", dport, dserv, ")");
d74d141c 3151 logevent(buf);
51470298 3152 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
d74d141c 3153 PKT_INT, sport,
3154 PKT_STR, host,
3155 PKT_INT, dport,
3156 PKT_END);
9bf696b1 3157 do {
3158 crReturnV;
3159 } while (!ispkt);
51470298 3160 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3161 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
a8327734 3162 bombout((ssh,"Protocol confusion"));
9bf696b1 3163 crReturnV;
51470298 3164 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3165 c_write_str(ssh, "Server refused port"
3166 " forwarding\r\n");
9bf696b1 3167 }
3168 logevent("Remote port forwarding enabled");
d74d141c 3169 }
3170 }
3171 }
3172 }
3173 }
3174
fef97f43 3175 if (!cfg.nopty) {
51470298 3176 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
32874aea 3177 PKT_STR, cfg.termtype,
51470298 3178 PKT_INT, ssh->term_height,
3179 PKT_INT, ssh->term_width,
32874aea 3180 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
51470298 3181 ssh->state = SSH_STATE_INTERMED;
32874aea 3182 do {
3183 crReturnV;
3184 } while (!ispkt);
51470298 3185 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3186 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
a8327734 3187 bombout((ssh,"Protocol confusion"));
32874aea 3188 crReturnV;
51470298 3189 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3190 c_write_str(ssh, "Server refused to allocate pty\r\n");
3191 ssh->editing = ssh->echoing = 1;
32874aea 3192 }
c5e9c988 3193 logevent("Allocated pty");
0965bee0 3194 } else {
51470298 3195 ssh->editing = ssh->echoing = 1;
374330e2 3196 }
3197
4ba9b64b 3198 if (cfg.compression) {
51470298 3199 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
32874aea 3200 do {
3201 crReturnV;
3202 } while (!ispkt);
51470298 3203 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3204 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
a8327734 3205 bombout((ssh,"Protocol confusion"));
32874aea 3206 crReturnV;
51470298 3207 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3208 c_write_str(ssh, "Server refused to compress\r\n");
32874aea 3209 }
4ba9b64b 3210 logevent("Started compression");
51470298 3211 ssh->v1_compressing = TRUE;
5366aed8 3212 ssh->cs_comp_ctx = zlib_compress_init();
3213 logevent("Initialised zlib (RFC1950) compression");
3214 ssh->sc_comp_ctx = zlib_decompress_init();
3215 logevent("Initialised zlib (RFC1950) decompression");
4ba9b64b 3216 }
3217
fd5e5847 3218 /*
3219 * Start the shell or command.
3220 *
3221 * Special case: if the first-choice command is an SSH2
3222 * subsystem (hence not usable here) and the second choice
3223 * exists, we fall straight back to that.
3224 */
3225 {
3226 char *cmd = cfg.remote_cmd_ptr;
3227
3228 if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) {
3229 cmd = cfg.remote_cmd_ptr2;
51470298 3230 ssh->fallback_cmd = TRUE;
fd5e5847 3231 }
3232 if (*cmd)
51470298 3233 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
fd5e5847 3234 else
51470298 3235 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
fd5e5847 3236 logevent("Started session");
3237 }
374330e2 3238
51470298 3239 ssh->state = SSH_STATE_SESSION;
3240 if (ssh->size_needed)
3241 ssh_size(ssh, ssh->term_width, ssh->term_height);
3242 if (ssh->eof_needed)
3243 ssh_special(ssh, TS_EOF);
374330e2 3244
b9d7bcad 3245 if (ssh->ldisc)
3246 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
51470298 3247 ssh->send_ok = 1;
3248 ssh->channels = newtree234(ssh_channelcmp);
374330e2 3249 while (1) {
3250 crReturnV;
3251 if (ispkt) {
51470298 3252 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3253 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3254 long len = GET_32BIT(ssh->pktin.body);
5471d09a 3255 int bufsize =
51470298 3256 from_backend(ssh->frontend,
3257 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3258 ssh->pktin.body + 4, len);
3259 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3260 ssh->v1_stdout_throttling = 1;
3261 ssh1_throttle(ssh, +1);
5471d09a 3262 }
51470298 3263 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3264 ssh->state = SSH_STATE_CLOSED;
c5e9c988 3265 logevent("Received disconnect request");
32874aea 3266 crReturnV;
51470298 3267 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
32874aea 3268 /* Remote side is trying to open a channel to talk to our
3269 * X-Server. Give them back a local channel number. */
3270 struct ssh_channel *c;
9c964e85 3271
3272 logevent("Received X11 connect request");
3273 /* Refuse if X11 forwarding is disabled. */
51470298 3274 if (!ssh->X11_fwd_enabled) {
3275 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3276 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
9c964e85 3277 logevent("Rejected X11 connect request");
3278 } else {
9c964e85 3279 c = smalloc(sizeof(struct ssh_channel));
51470298 3280 c->ssh = ssh;
9c964e85 3281
302121de 3282 if (x11_init(&c->u.x11.s, cfg.x11_display, c,
3283 ssh->x11auth) != NULL) {
32874aea 3284 logevent("opening X11 forward connection failed");
3285 sfree(c);
51470298 3286 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3287 PKT_INT, GET_32BIT(ssh->pktin.body),
32874aea 3288 PKT_END);
9c964e85 3289 } else {
32874aea 3290 logevent
3291 ("opening X11 forward connection succeeded");
51470298 3292 c->remoteid = GET_32BIT(ssh->pktin.body);
3293 c->localid = alloc_channel_id(ssh);
32874aea 3294 c->closes = 0;
5471d09a 3295 c->v.v1.throttling = 0;
32874aea 3296 c->type = CHAN_X11; /* identify channel type */
51470298 3297 add234(ssh->channels, c);
3298 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
32874aea 3299 PKT_INT, c->remoteid, PKT_INT,
3300 c->localid, PKT_END);
3301 logevent("Opened X11 forward channel");
9c964e85 3302 }
3303 }
51470298 3304 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
32874aea 3305 /* Remote side is trying to open a channel to talk to our
3306 * agent. Give them back a local channel number. */
3307 struct ssh_channel *c;
db7d555c 3308
3309 /* Refuse if agent forwarding is disabled. */
51470298 3310 if (!ssh->agentfwd_enabled) {
3311 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3312 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
db7d555c 3313 } else {
dcbde236 3314 c = smalloc(sizeof(struct ssh_channel));
51470298 3315 c->ssh = ssh;
3316 c->remoteid = GET_32BIT(ssh->pktin.body);
3317 c->localid = alloc_channel_id(ssh);
db7d555c 3318 c->closes = 0;
5471d09a 3319 c->v.v1.throttling = 0;
32874aea 3320 c->type = CHAN_AGENT; /* identify channel type */
db7d555c 3321 c->u.a.lensofar = 0;
51470298 3322 add234(ssh->channels, c);
3323 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
db7d555c 3324 PKT_INT, c->remoteid, PKT_INT, c->localid,
3325 PKT_END);
3326 }
51470298 3327 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
d74d141c 3328 /* Remote side is trying to open a channel to talk to a
3329 * forwarded port. Give them back a local channel number. */
3330 struct ssh_channel *c;
3331 struct ssh_rportfwd pf;
3332 int hostsize, port;
3333 char host[256], buf[1024];
3334 char *p, *h, *e;
3335 c = smalloc(sizeof(struct ssh_channel));
51470298 3336 c->ssh = ssh;
d74d141c 3337
51470298 3338 hostsize = GET_32BIT(ssh->pktin.body+4);
3339 for(h = host, p = ssh->pktin.body+8; hostsize != 0; hostsize--) {
d74d141c 3340 if (h+1 < host+sizeof(host))
3341 *h++ = *p;
95bc8819 3342 p++;
d74d141c 3343 }
3344 *h = 0;
3345 port = GET_32BIT(p);
3346
bc240b21 3347 strcpy(pf.dhost, host);
3348 pf.dport = port;
d74d141c 3349
51470298 3350 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
d74d141c 3351 sprintf(buf, "Rejected remote port open request for %s:%d",
3352 host, port);
3353 logevent(buf);
51470298 3354 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3355 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
d74d141c 3356 } else {
3357 sprintf(buf, "Received remote port open request for %s:%d",
3358 host, port);
3359 logevent(buf);
3360 e = pfd_newconnect(&c->u.pfd.s, host, port, c);
3361 if (e != NULL) {
3362 char buf[256];
3363 sprintf(buf, "Port open failed: %s", e);
3364 logevent(buf);
3365 sfree(c);
51470298 3366 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3367 PKT_INT, GET_32BIT(ssh->pktin.body),
d74d141c 3368 PKT_END);
3369 } else {
51470298 3370 c->remoteid = GET_32BIT(ssh->pktin.body);
3371 c->localid = alloc_channel_id(ssh);
d74d141c 3372 c->closes = 0;
5471d09a 3373 c->v.v1.throttling = 0;
d74d141c 3374 c->type = CHAN_SOCKDATA; /* identify channel type */
51470298 3375 add234(ssh->channels, c);
3376 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
d74d141c 3377 PKT_INT, c->remoteid, PKT_INT,
3378 c->localid, PKT_END);
3379 logevent("Forwarded port opened successfully");
3380 }
3381 }
3382
51470298 3383 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3384 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3385 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
bc240b21 3386 struct ssh_channel *c;
3387
51470298 3388 c = find234(ssh->channels, &remoteid, ssh_channelfind);
bc240b21 3389 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3390 c->remoteid = localid;
3391 c->type = CHAN_SOCKDATA;
7781f316 3392 c->v.v1.throttling = 0;
bc240b21 3393 pfd_confirm(c->u.pfd.s);
3394 }
d74d141c 3395
4ed34d25 3396 if (c && c->closes) {
3397 /*
3398 * We have a pending close on this channel,
3399 * which we decided on before the server acked
3400 * the channel open. So now we know the
3401 * remoteid, we can close it again.
3402 */
51470298 3403 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3404 PKT_INT, c->remoteid, PKT_END);
4ed34d25 3405 }
3406
51470298 3407 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3408 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
724cface 3409 struct ssh_channel *c;
3410
51470298 3411 c = find234(ssh->channels, &remoteid, ssh_channelfind);
724cface 3412 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3413 logevent("Forwarded connection refused by server");
3414 pfd_close(c->u.pfd.s);
51470298 3415 del234(ssh->channels, c);
724cface 3416 sfree(c);
3417 }
3418
51470298 3419 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3420 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
32874aea 3421 /* Remote side closes a channel. */
51470298 3422 unsigned i = GET_32BIT(ssh->pktin.body);
32874aea 3423 struct ssh_channel *c;
51470298 3424 c = find234(ssh->channels, &i, ssh_channelfind);
d0d844c1 3425 if (c && ((int)c->remoteid) != -1) {
32874aea 3426 int closetype;
3427 closetype =
51470298 3428 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
0357890f 3429
783415f8 3430 if ((c->closes == 0) && (c->type == CHAN_X11)) {
d74d141c 3431 logevent("Forwarded X11 connection terminated");
9c964e85 3432 assert(c->u.x11.s != NULL);
3433 x11_close(c->u.x11.s);
3434 c->u.x11.s = NULL;
3435 }
d74d141c 3436 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3437 logevent("Forwarded port closed");
3438 assert(c->u.pfd.s != NULL);
3439 pfd_close(c->u.pfd.s);
3440 c->u.pfd.s = NULL;
3441 }
0357890f 3442
3443 c->closes |= (closetype << 2); /* seen this message */
3444 if (!(c->closes & closetype)) {
51470298 3445 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
0357890f 3446 PKT_END);
3447 c->closes |= closetype; /* sent it too */
3448 }
3449
3450 if (c->closes == 15) {
51470298 3451 del234(ssh->channels, c);
32874aea 3452 sfree(c);
3453 }
d0d844c1 3454 } else {
a8327734 3455 bombout((ssh,"Received CHANNEL_CLOSE%s for %s channel %d\n",
51470298 3456 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
d0d844c1 3457 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3458 i));
32874aea 3459 }
51470298 3460 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
32874aea 3461 /* Data sent down one of our channels. */
51470298 3462 int i = GET_32BIT(ssh->pktin.body);
3463 int len = GET_32BIT(ssh->pktin.body + 4);
3464 unsigned char *p = ssh->pktin.body + 8;
32874aea 3465 struct ssh_channel *c;
51470298 3466 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 3467 if (c) {
5471d09a 3468 int bufsize;
32874aea 3469 switch (c->type) {
3470 case CHAN_X11:
5471d09a 3471 bufsize = x11_send(c->u.x11.s, p, len);
9c964e85 3472 break;
d74d141c 3473 case CHAN_SOCKDATA:
5471d09a 3474 bufsize = pfd_send(c->u.pfd.s, p, len);
bc240b21 3475 break;
32874aea 3476 case CHAN_AGENT:
3477 /* Data for an agent message. Buffer it. */
3478 while (len > 0) {
3479 if (c->u.a.lensofar < 4) {
3480 int l = min(4 - c->u.a.lensofar, len);
3481 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3482 l);
3483 p += l;
3484 len -= l;
3485 c->u.a.lensofar += l;
3486 }
3487 if (c->u.a.lensofar == 4) {
3488 c->u.a.totallen =
3489 4 + GET_32BIT(c->u.a.msglen);
3490 c->u.a.message = smalloc(c->u.a.totallen);
3491 memcpy(c->u.a.message, c->u.a.msglen, 4);
3492 }
3493 if (c->u.a.lensofar >= 4 && len > 0) {
3494 int l =
3495 min(c->u.a.totallen - c->u.a.lensofar,
3496 len);
3497 memcpy(c->u.a.message + c->u.a.lensofar, p,
3498 l);
3499 p += l;
3500 len -= l;
3501 c->u.a.lensofar += l;
3502 }
3503 if (c->u.a.lensofar == c->u.a.totallen) {
3504 void *reply, *sentreply;
3505 int replylen;
3506 agent_query(c->u.a.message,
3507 c->u.a.totallen, &reply,
3508 &replylen);
3509 if (reply)
3510 sentreply = reply;
3511 else {
3512 /* Fake SSH_AGENT_FAILURE. */
3513 sentreply = "\0\0\0\1\5";
3514 replylen = 5;
3515 }
51470298 3516 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
32874aea 3517 PKT_INT, c->remoteid,
3518 PKT_INT, replylen,
3519 PKT_DATA, sentreply, replylen,
3520 PKT_END);
3521 if (reply)
3522 sfree(reply);
3523 sfree(c->u.a.message);
3524 c->u.a.lensofar = 0;
3525 }
3526 }
5471d09a 3527 bufsize = 0; /* agent channels never back up */
32874aea 3528 break;
3529 }
90347b95 3530 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
5471d09a 3531 c->v.v1.throttling = 1;
51470298 3532 ssh1_throttle(ssh, +1);
5471d09a 3533 }
32874aea 3534 }
51470298 3535 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
972a41c8 3536 /* may be from EXEC_SHELL on some servers */
51470298 3537 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
972a41c8 3538 /* may be from EXEC_SHELL on some servers
374330e2 3539 * if no pty is available or in other odd cases. Ignore */
51470298 3540 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
d8d6c7e5 3541 char buf[100];
51470298 3542 ssh->exitcode = GET_32BIT(ssh->pktin.body);
d8d6c7e5 3543 sprintf(buf, "Server sent command exit status %d",
51470298 3544 ssh->exitcode);
d8d6c7e5 3545 logevent(buf);
51470298 3546 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
4252c9cc 3547 /*
3548 * In case `helpful' firewalls or proxies tack
3549 * extra human-readable text on the end of the
3550 * session which we might mistake for another
3551 * encrypted packet, we close the session once
3552 * we've sent EXIT_CONFIRMATION.
3553 */
51470298 3554 ssh->state = SSH_STATE_CLOSED;
4252c9cc 3555 crReturnV;
374330e2 3556 } else {
a8327734 3557 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
32874aea 3558 crReturnV;
374330e2 3559 }
3560 } else {
8df7a775 3561 while (inlen > 0) {
3562 int len = min(inlen, 512);
51470298 3563 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
8df7a775 3564 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3565 in += len;
3566 inlen -= len;
3567 }
374330e2 3568 }
3569 }
3570
3571 crFinishV;
3572}
3573
3574/*
e5574168 3575 * Utility routine for decoding comma-separated strings in KEXINIT.
3576 */
32874aea 3577static int in_commasep_string(char *needle, char *haystack, int haylen)
3578{
e5574168 3579 int needlen = strlen(needle);
3580 while (1) {
32874aea 3581 /*
3582 * Is it at the start of the string?
3583 */
3584 if (haylen >= needlen && /* haystack is long enough */
3585 !memcmp(needle, haystack, needlen) && /* initial match */
3586 (haylen == needlen || haystack[needlen] == ',')
3587 /* either , or EOS follows */
3588 )
3589 return 1;
3590 /*
3591 * If not, search for the next comma and resume after that.
3592 * If no comma found, terminate.
3593 */
3594 while (haylen > 0 && *haystack != ',')
3595 haylen--, haystack++;
3596 if (haylen == 0)
3597 return 0;
3598 haylen--, haystack++; /* skip over comma itself */
e5574168 3599 }
3600}
3601
3602/*
d39f364a 3603 * SSH2 key creation method.
3604 */
51470298 3605static void ssh2_mkkey(Ssh ssh, Bignum K, char *H, char *sessid, char chr,
32874aea 3606 char *keyspace)
3607{
d39f364a 3608 SHA_State s;
3609 /* First 20 bytes. */
3610 SHA_Init(&s);
51470298 3611 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
088bde77 3612 sha_mpint(&s, K);
d39f364a 3613 SHA_Bytes(&s, H, 20);
3614 SHA_Bytes(&s, &chr, 1);
5e0d7cb8 3615 SHA_Bytes(&s, sessid, 20);
d39f364a 3616 SHA_Final(&s, keyspace);
3617 /* Next 20 bytes. */
3618 SHA_Init(&s);
51470298 3619 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
088bde77 3620 sha_mpint(&s, K);
d39f364a 3621 SHA_Bytes(&s, H, 20);
3622 SHA_Bytes(&s, keyspace, 20);
32874aea 3623 SHA_Final(&s, keyspace + 20);
d39f364a 3624}
3625
3626/*
7cca0d81 3627 * Handle the SSH2 transport layer.
e5574168 3628 */
51470298 3629static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
e5574168 3630{
51470298 3631 struct do_ssh2_transport_state {
3632 int nbits, pbits, warn;
3633 Bignum p, g, e, f, K;
3634 int kex_init_value, kex_reply_value;
3635 const struct ssh_mac **maclist;
3636 int nmacs;
3637 const struct ssh2_cipher *cscipher_tobe;
3638 const struct ssh2_cipher *sccipher_tobe;
3639 const struct ssh_mac *csmac_tobe;
3640 const struct ssh_mac *scmac_tobe;
3641 const struct ssh_compress *cscomp_tobe;
3642 const struct ssh_compress *sccomp_tobe;
3643 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3644 int hostkeylen, siglen;
3645 void *hkey; /* actual host key */
3646 unsigned char exchange_hash[20];
3647 int n_preferred_ciphers;
3648 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3649 const struct ssh_compress *preferred_comp;
3650 int first_kex;
3651 };
3652 crState(do_ssh2_transport_state);
3653
3654 crBegin(ssh->do_ssh2_transport_crstate);
3655
3656 s->cscipher_tobe = s->sccipher_tobe = NULL;
3657 s->csmac_tobe = s->scmac_tobe = NULL;
3658 s->cscomp_tobe = s->sccomp_tobe = NULL;
3659
7cca0d81 3660 random_init();
51470298 3661 s->first_kex = 1;
e5574168 3662
51470298 3663 {
3664 int i;
3665 /*
3666 * Set up the preferred ciphers. (NULL => warn below here)
3667 */
3668 s->n_preferred_ciphers = 0;
3669 for (i = 0; i < CIPHER_MAX; i++) {
3670 switch (cfg.ssh_cipherlist[i]) {
3671 case CIPHER_BLOWFISH:
3672 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3673 break;
3674 case CIPHER_DES:
3675 if (cfg.ssh2_des_cbc) {
3676 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3677 }
3678 break;
3679 case CIPHER_3DES:
3680 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3681 break;
3682 case CIPHER_AES:
3683 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3684 break;
3685 case CIPHER_WARN:
3686 /* Flag for later. Don't bother if it's the last in
3687 * the list. */
3688 if (i < CIPHER_MAX - 1) {
3689 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3690 }
3691 break;
ca20bfcf 3692 }
ca20bfcf 3693 }
5e8358ad 3694 }
ca20bfcf 3695
3696 /*
3697 * Set up preferred compression.
3698 */
4ba9b64b 3699 if (cfg.compression)
51470298 3700 s->preferred_comp = &ssh_zlib;
4ba9b64b 3701 else
51470298 3702 s->preferred_comp = &ssh_comp_none;
5e8358ad 3703
7591b9ff 3704 /*
3705 * Be prepared to work around the buggy MAC problem.
3706 */
51470298 3707 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3708 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
7591b9ff 3709 else
51470298 3710 s->maclist = macs, s->nmacs = lenof(macs);
7591b9ff 3711
32874aea 3712 begin_key_exchange:
51470298 3713 {
3714 int i, j, cipherstr_started;
3715
3716 /*
3717 * Construct and send our key exchange packet.
3718 */
3719 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3720 for (i = 0; i < 16; i++)
3721 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3722 /* List key exchange algorithms. */
3723 ssh2_pkt_addstring_start(ssh);
3724 for (i = 0; i < lenof(kex_algs); i++) {
3725 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3726 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3727 continue;
3728 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3729 if (i < lenof(kex_algs) - 1)
3730 ssh2_pkt_addstring_str(ssh, ",");
32874aea 3731 }
51470298 3732 /* List server host key algorithms. */
3733 ssh2_pkt_addstring_start(ssh);
3734 for (i = 0; i < lenof(hostkey_algs); i++) {
3735 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3736 if (i < lenof(hostkey_algs) - 1)
3737 ssh2_pkt_addstring_str(ssh, ",");
32874aea 3738 }
51470298 3739 /* List client->server encryption algorithms. */
3740 ssh2_pkt_addstring_start(ssh);
3741 cipherstr_started = 0;
3742 for (i = 0; i < s->n_preferred_ciphers; i++) {
3743 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3744 if (!c) continue; /* warning flag */
3745 for (j = 0; j < c->nciphers; j++) {
3746 if (cipherstr_started)
3747 ssh2_pkt_addstring_str(ssh, ",");
3748 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3749 cipherstr_started = 1;
3750 }
3751 }
3752 /* List server->client encryption algorithms. */
3753 ssh2_pkt_addstring_start(ssh);
3754 cipherstr_started = 0;
3755 for (i = 0; i < s->n_preferred_ciphers; i++) {
3756 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3757 if (!c) continue; /* warning flag */
3758 for (j = 0; j < c->nciphers; j++) {
3759 if (cipherstr_started)
3760 ssh2_pkt_addstring_str(ssh, ",");
3761 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3762 cipherstr_started = 1;
3763 }
3764 }
3765 /* List client->server MAC algorithms. */
3766 ssh2_pkt_addstring_start(ssh);
3767 for (i = 0; i < s->nmacs; i++) {
3768 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3769 if (i < s->nmacs - 1)
3770 ssh2_pkt_addstring_str(ssh, ",");
3771 }
3772 /* List server->client MAC algorithms. */
3773 ssh2_pkt_addstring_start(ssh);
3774 for (i = 0; i < s->nmacs; i++) {
3775 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3776 if (i < s->nmacs - 1)
3777 ssh2_pkt_addstring_str(ssh, ",");
3778 }
3779 /* List client->server compression algorithms. */
3780 ssh2_pkt_addstring_start(ssh);
3781 for (i = 0; i < lenof(compressions) + 1; i++) {
3782 const struct ssh_compress *c =
3783 i == 0 ? s->preferred_comp : compressions[i - 1];
3784 ssh2_pkt_addstring_str(ssh, c->name);
3785 if (i < lenof(compressions))
3786 ssh2_pkt_addstring_str(ssh, ",");
3787 }
3788 /* List server->client compression algorithms. */
3789 ssh2_pkt_addstring_start(ssh);
3790 for (i = 0; i < lenof(compressions) + 1; i++) {
3791 const struct ssh_compress *c =
3792 i == 0 ? s->preferred_comp : compressions[i - 1];
3793 ssh2_pkt_addstring_str(ssh, c->name);
3794 if (i < lenof(compressions))
3795 ssh2_pkt_addstring_str(ssh, ",");
3796 }
3797 /* List client->server languages. Empty list. */
3798 ssh2_pkt_addstring_start(ssh);
3799 /* List server->client languages. Empty list. */
3800 ssh2_pkt_addstring_start(ssh);
3801 /* First KEX packet does _not_ follow, because we're not that brave. */
3802 ssh2_pkt_addbool(ssh, FALSE);
3803 /* Reserved. */
3804 ssh2_pkt_adduint32(ssh, 0);
e5574168 3805 }
0db56f73 3806
51470298 3807 ssh->exhash = ssh->exhashbase;
3808 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
0db56f73 3809
51470298 3810 ssh2_pkt_send(ssh);
e5574168 3811
32874aea 3812 if (!ispkt)
3813 crWaitUntil(ispkt);
51470298 3814 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
e5574168 3815
3816 /*
3817 * Now examine the other side's KEXINIT to see what we're up
3818 * to.
3819 */
51470298 3820 {
3821 char *str;
3822 int i, j, len;
3823
3824 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
a8327734 3825 bombout((ssh,"expected key exchange packet from server"));
51470298 3826 crReturn(0);
32874aea 3827 }
51470298 3828 ssh->kex = NULL;
3829 ssh->hostkey = NULL;
3830 s->cscipher_tobe = NULL;
3831 s->sccipher_tobe = NULL;
3832 s->csmac_tobe = NULL;
3833 s->scmac_tobe = NULL;
3834 s->cscomp_tobe = NULL;
3835 s->sccomp_tobe = NULL;
3836 ssh->pktin.savedpos += 16; /* skip garbage cookie */
3837 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
3838 for (i = 0; i < lenof(kex_algs); i++) {
3839 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3840 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3841 continue;
3842 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3843 ssh->kex = kex_algs[i];
3844 break;
3845 }
32874aea 3846 }
51470298 3847 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
3848 for (i = 0; i < lenof(hostkey_algs); i++) {
3849 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3850 ssh->hostkey = hostkey_algs[i];
3851 break;
3852 }
3853 }
3854 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
3855 s->warn = 0;
3856 for (i = 0; i < s->n_preferred_ciphers; i++) {
3857 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3858 if (!c) {
3859 s->warn = 1;
3860 } else {
3861 for (j = 0; j < c->nciphers; j++) {
3862 if (in_commasep_string(c->list[j]->name, str, len)) {
3863 s->cscipher_tobe = c->list[j];
3864 break;
3865 }
ca20bfcf 3866 }
32874aea 3867 }
51470298 3868 if (s->cscipher_tobe) {
3869 if (s->warn)
a8327734 3870 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
51470298 3871 break;
3872 }
32874aea 3873 }
51470298 3874 if (!s->cscipher_tobe) {
a8327734 3875 bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)", str));
51470298 3876 crReturn(0);
ca20bfcf 3877 }
0ef8f407 3878
51470298 3879 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
3880 s->warn = 0;
3881 for (i = 0; i < s->n_preferred_ciphers; i++) {
3882 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3883 if (!c) {
3884 s->warn = 1;
3885 } else {
3886 for (j = 0; j < c->nciphers; j++) {
3887 if (in_commasep_string(c->list[j]->name, str, len)) {
3888 s->sccipher_tobe = c->list[j];
3889 break;
3890 }
ca20bfcf 3891 }
32874aea 3892 }
51470298 3893 if (s->sccipher_tobe) {
3894 if (s->warn)
a8327734 3895 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
51470298 3896 break;
3897 }
32874aea 3898 }
51470298 3899 if (!s->sccipher_tobe) {
a8327734 3900 bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)", str));
51470298 3901 crReturn(0);
ca20bfcf 3902 }
0ef8f407 3903
51470298 3904 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
3905 for (i = 0; i < s->nmacs; i++) {
3906 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3907 s->csmac_tobe = s->maclist[i];
3908 break;
3909 }
32874aea 3910 }
51470298 3911 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
3912 for (i = 0; i < s->nmacs; i++) {
3913 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3914 s->scmac_tobe = s->maclist[i];
3915 break;
3916 }
32874aea 3917 }
51470298 3918 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
3919 for (i = 0; i < lenof(compressions) + 1; i++) {
3920 const struct ssh_compress *c =
3921 i == 0 ? s->preferred_comp : compressions[i - 1];
3922 if (in_commasep_string(c->name, str, len)) {
3923 s->cscomp_tobe = c;
3924 break;
3925 }
32874aea 3926 }
51470298 3927 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
3928 for (i = 0; i < lenof(compressions) + 1; i++) {
3929 const struct ssh_compress *c =
3930 i == 0 ? s->preferred_comp : compressions[i - 1];
3931 if (in_commasep_string(c->name, str, len)) {
3932 s->sccomp_tobe = c;
3933 break;
3934 }
32874aea 3935 }
e5574168 3936 }
e5574168 3937
3938 /*
7bd5a860 3939 * Work out the number of bits of key we will need from the key
3940 * exchange. We start with the maximum key length of either
3941 * cipher...
3942 */
3943 {
32874aea 3944 int csbits, scbits;
7bd5a860 3945
51470298 3946 csbits = s->cscipher_tobe->keylen;
3947 scbits = s->sccipher_tobe->keylen;
3948 s->nbits = (csbits > scbits ? csbits : scbits);
7bd5a860 3949 }
3950 /* The keys only have 160-bit entropy, since they're based on
3951 * a SHA-1 hash. So cap the key size at 160 bits. */
51470298 3952 if (s->nbits > 160)
3953 s->nbits = 160;
7bd5a860 3954
3955 /*
a92dd380 3956 * If we're doing Diffie-Hellman group exchange, start by
3957 * requesting a group.
e5574168 3958 */
51470298 3959 if (ssh->kex == &ssh_diffiehellman_gex) {
32874aea 3960 logevent("Doing Diffie-Hellman group exchange");
51470298 3961 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
32874aea 3962 /*
3963 * Work out how big a DH group we will need to allow that
3964 * much data.
7bd5a860 3965 */
51470298 3966 s->pbits = 512 << ((s->nbits - 1) / 64);
3967 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
3968 ssh2_pkt_adduint32(ssh, s->pbits);
3969 ssh2_pkt_send(ssh);
32874aea 3970
3971 crWaitUntil(ispkt);
51470298 3972 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
a8327734 3973 bombout((ssh,"expected key exchange group packet from server"));
32874aea 3974 crReturn(0);
3975 }
51470298 3976 s->p = ssh2_pkt_getmp(ssh);
3977 s->g = ssh2_pkt_getmp(ssh);
27cd7fc2 3978 ssh->kex_ctx = dh_setup_group(s->p, s->g);
51470298 3979 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
3980 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
a92dd380 3981 } else {
51470298 3982 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
27cd7fc2 3983 ssh->kex_ctx = dh_setup_group1();
51470298 3984 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
3985 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
8d5de777 3986 }
e5574168 3987
a92dd380 3988 logevent("Doing Diffie-Hellman key exchange");
e5574168 3989 /*
a92dd380 3990 * Now generate and send e for Diffie-Hellman.
e5574168 3991 */
27cd7fc2 3992 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
51470298 3993 ssh2_pkt_init(ssh, s->kex_init_value);
3994 ssh2_pkt_addmp(ssh, s->e);
3995 ssh2_pkt_send(ssh);
e5574168 3996
3997 crWaitUntil(ispkt);
51470298 3998 if (ssh->pktin.type != s->kex_reply_value) {
a8327734 3999 bombout((ssh,"expected key exchange reply packet from server"));
32874aea 4000 crReturn(0);
7cca0d81 4001 }
51470298 4002 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4003 s->f = ssh2_pkt_getmp(ssh);
4004 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
e5574168 4005
27cd7fc2 4006 s->K = dh_find_K(ssh->kex_ctx, s->f);
e5574168 4007
51470298 4008 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4009 if (ssh->kex == &ssh_diffiehellman_gex) {
4010 sha_uint32(&ssh->exhash, s->pbits);
4011 sha_mpint(&ssh->exhash, s->p);
4012 sha_mpint(&ssh->exhash, s->g);
a92dd380 4013 }
51470298 4014 sha_mpint(&ssh->exhash, s->e);
4015 sha_mpint(&ssh->exhash, s->f);
4016 sha_mpint(&ssh->exhash, s->K);
4017 SHA_Final(&ssh->exhash, s->exchange_hash);
e5574168 4018
27cd7fc2 4019 dh_cleanup(ssh->kex_ctx);
3709bfe9 4020
7cca0d81 4021#if 0
765c4200 4022 debug(("Exchange hash is:\n"));
51470298 4023 dmemdump(s->exchange_hash, 20);
7cca0d81 4024#endif
4025
51470298 4026 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4027 if (!s->hkey ||
4028 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4029 s->exchange_hash, 20)) {
a8327734 4030 bombout((ssh,"Server's host key did not match the signature supplied"));
32874aea 4031 crReturn(0);
8d5de777 4032 }
e5574168 4033
4034 /*
7cca0d81 4035 * Authenticate remote host: verify host key. (We've already
4036 * checked the signature of the exchange hash.)
e5574168 4037 */
51470298 4038 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4039 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
a8327734 4040 verify_ssh_host_key(ssh->frontend,
4041 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
51470298 4042 s->keystr, s->fingerprint);
4043 if (s->first_kex) { /* don't bother logging this in rekeys */
5e0d7cb8 4044 logevent("Host key fingerprint is:");
51470298 4045 logevent(s->fingerprint);
5e0d7cb8 4046 }
51470298 4047 sfree(s->fingerprint);
4048 sfree(s->keystr);
4049 ssh->hostkey->freekey(s->hkey);
d39f364a 4050
4051 /*
7cca0d81 4052 * Send SSH2_MSG_NEWKEYS.
d39f364a 4053 */
51470298 4054 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4055 ssh2_pkt_send(ssh);
d39f364a 4056
4057 /*
8406eaf9 4058 * Expect SSH2_MSG_NEWKEYS from server.
4059 */
4060 crWaitUntil(ispkt);
51470298 4061 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
a8327734 4062 bombout((ssh,"expected new-keys packet from server"));
8406eaf9 4063 crReturn(0);
4064 }
4065
4066 /*
d39f364a 4067 * Create and initialise session keys.
4068 */
371e569c 4069 if (ssh->cs_cipher_ctx)
4070 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
51470298 4071 ssh->cscipher = s->cscipher_tobe;
371e569c 4072 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
e0e1a00d 4073
371e569c 4074 if (ssh->sc_cipher_ctx)
4075 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
51470298 4076 ssh->sccipher = s->sccipher_tobe;
371e569c 4077 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
e0e1a00d 4078
4079 if (ssh->cs_mac_ctx)
4080 ssh->csmac->free_context(ssh->cs_mac_ctx);
51470298 4081 ssh->csmac = s->csmac_tobe;
e0e1a00d 4082 ssh->cs_mac_ctx = ssh->csmac->make_context();
4083
4084 if (ssh->sc_mac_ctx)
4085 ssh->scmac->free_context(ssh->sc_mac_ctx);
51470298 4086 ssh->scmac = s->scmac_tobe;
e0e1a00d 4087 ssh->sc_mac_ctx = ssh->scmac->make_context();
4088
5366aed8 4089 if (ssh->cs_comp_ctx)
4090 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
51470298 4091 ssh->cscomp = s->cscomp_tobe;
5366aed8 4092 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4093
4094 if (ssh->sc_comp_ctx)
4095 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
51470298 4096 ssh->sccomp = s->sccomp_tobe;
5366aed8 4097 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4098
d39f364a 4099 /*
5e0d7cb8 4100 * Set IVs after keys. Here we use the exchange hash from the
4101 * _first_ key exchange.
d39f364a 4102 */
51470298 4103 {
4104 unsigned char keyspace[40];
4105 if (s->first_kex)
4106 memcpy(ssh->v2_session_id, s->exchange_hash,
4107 sizeof(s->exchange_hash));
4108 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
371e569c 4109 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
51470298 4110 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
371e569c 4111 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
51470298 4112 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
371e569c 4113 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
51470298 4114 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
371e569c 4115 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
51470298 4116 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
e0e1a00d 4117 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
51470298 4118 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
e0e1a00d 4119 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
51470298 4120 }
371e569c 4121 {
4122 char buf[256];
4123 sprintf(buf, "Initialised %.200s client->server encryption",
4124 ssh->cscipher->text_name);
4125 logevent(buf);
4126 sprintf(buf, "Initialised %.200s server->client encryption",
4127 ssh->sccipher->text_name);
4128 logevent(buf);
5366aed8 4129 if (ssh->cscomp->text_name) {
4130 sprintf(buf, "Initialised %.200s compression",
4131 ssh->cscomp->text_name);
4132 logevent(buf);
4133 }
4134 if (ssh->sccomp->text_name) {
4135 sprintf(buf, "Initialised %.200s decompression",
4136 ssh->sccomp->text_name);
4137 logevent(buf);
4138 }
371e569c 4139 }
4140
d39f364a 4141
033b4cef 4142 /*
0db56f73 4143 * If this is the first key exchange phase, we must pass the
4144 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4145 * wants to see it but because it will need time to initialise
4146 * itself before it sees an actual packet. In subsequent key
4147 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4148 * it would only confuse the layer above.
4149 */
51470298 4150 if (!s->first_kex) {
32874aea 4151 crReturn(0);
0db56f73 4152 }
51470298 4153 s->first_kex = 0;
0db56f73 4154
4155 /*
7cca0d81 4156 * Now we're encrypting. Begin returning 1 to the protocol main
4157 * function so that other things can run on top of the
4158 * transport. If we ever see a KEXINIT, we must go back to the
4159 * start.
033b4cef 4160 */
51470298 4161 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
32874aea 4162 crReturn(1);
e96adf72 4163 }
5e0d7cb8 4164 logevent("Server initiated key re-exchange");
7cca0d81 4165 goto begin_key_exchange;
e5574168 4166
4167 crFinish(1);
4168}
4169
7cca0d81 4170/*
783415f8 4171 * Add data to an SSH2 channel output buffer.
4172 */
32874aea 4173static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4174 int len)
4175{
5471d09a 4176 bufchain_add(&c->v.v2.outbuffer, buf, len);
783415f8 4177}
4178
4179/*
4180 * Attempt to send data on an SSH2 channel.
4181 */
5471d09a 4182static int ssh2_try_send(struct ssh_channel *c)
32874aea 4183{
51470298 4184 Ssh ssh = c->ssh;
4185
5471d09a 4186 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4187 int len;
4188 void *data;
4189 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4190 if ((unsigned)len > c->v.v2.remwindow)
4191 len = c->v.v2.remwindow;
4192 if ((unsigned)len > c->v.v2.remmaxpkt)
4193 len = c->v.v2.remmaxpkt;
51470298 4194 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4195 ssh2_pkt_adduint32(ssh, c->remoteid);
4196 ssh2_pkt_addstring_start(ssh);
4197 ssh2_pkt_addstring_data(ssh, data, len);
4198 ssh2_pkt_send(ssh);
5471d09a 4199 bufchain_consume(&c->v.v2.outbuffer, len);
4200 c->v.v2.remwindow -= len;
4201 }
4202
4203 /*
4204 * After having sent as much data as we can, return the amount
4205 * still buffered.
4206 */
4207 return bufchain_size(&c->v.v2.outbuffer);
4208}
4209
4210/*
4211 * Potentially enlarge the window on an SSH2 channel.
4212 */
4213static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4214{
51470298 4215 Ssh ssh = c->ssh;
4216
6b69f42e 4217 /*
4218 * Never send WINDOW_ADJUST for a channel that the remote side
4219 * already thinks it's closed; there's no point, since it won't
4220 * be sending any more data anyway.
4221 */
4222 if (c->closes != 0)
4223 return;
4224
5471d09a 4225 if (newwin > c->v.v2.locwindow) {
51470298 4226 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4227 ssh2_pkt_adduint32(ssh, c->remoteid);
4228 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4229 ssh2_pkt_send(ssh);
5471d09a 4230 c->v.v2.locwindow = newwin;
783415f8 4231 }
4232}
4233
4234/*
7cca0d81 4235 * Handle the SSH2 userauth and connection layers.
4236 */
51470298 4237static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
7cca0d81 4238{
51470298 4239 struct do_ssh2_authconn_state {
4240 enum {
4241 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4242 AUTH_PASSWORD,
4243 AUTH_KEYBOARD_INTERACTIVE
4244 } method;
4245 enum {
4246 AUTH_TYPE_NONE,
4247 AUTH_TYPE_PUBLICKEY,
4248 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4249 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4250 AUTH_TYPE_PASSWORD,
4251 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4252 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4253 } type;
4254 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4255 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4256 int kbd_inter_running;
4257 int we_are_in;
4258 int num_prompts, curr_prompt, echo;
4259 char username[100];
4260 int got_username;
4261 char pwprompt[200];
4262 char password[100];
4263 void *publickey_blob;
4264 int publickey_bloblen;
4265 unsigned char request[5], *response, *p;
4266 int responselen;
4267 int keyi, nkeys;
4268 int authed;
4269 char *pkblob, *alg, *commentp;
4270 int pklen, alglen, commentlen;
4271 int siglen, retlen, len;
4272 char *q, *agentreq, *ret;
4273 int try_send;
4274 };
4275 crState(do_ssh2_authconn_state);
4276
4277 crBegin(ssh->do_ssh2_authconn_crstate);
e5574168 4278
7cca0d81 4279 /*
4280 * Request userauth protocol, and await a response to it.
4281 */
51470298 4282 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4283 ssh2_pkt_addstring(ssh, "ssh-userauth");
4284 ssh2_pkt_send(ssh);
7cca0d81 4285 crWaitUntilV(ispkt);
51470298 4286 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
a8327734 4287 bombout((ssh,"Server refused user authentication protocol"));
32874aea 4288 crReturnV;
8d5de777 4289 }
7cca0d81 4290
4291 /*
1408a877 4292 * We repeat this whole loop, including the username prompt,
4293 * until we manage a successful authentication. If the user
51470298 4294 * types the wrong _password_, they can be sent back to the
4295 * beginning to try another username, if this is configured on.
4296 * (If they specify a username in the config, they are never
4297 * asked, even if they do give a wrong password.)
1408a877 4298 *
4299 * I think this best serves the needs of
4300 *
4301 * - the people who have no configuration, no keys, and just
4302 * want to try repeated (username,password) pairs until they
4303 * type both correctly
4304 *
4305 * - people who have keys and configuration but occasionally
4306 * need to fall back to passwords
4307 *
4308 * - people with a key held in Pageant, who might not have
4309 * logged in to a particular machine before; so they want to
4310 * type a username, and then _either_ their key will be
4311 * accepted, _or_ they will type a password. If they mistype
4312 * the username they will want to be able to get back and
4313 * retype it!
7cca0d81 4314 */
51470298 4315 s->username[0] = '\0';
4316 s->got_username = FALSE;
1408a877 4317 do {
1408a877 4318 /*
4319 * Get a username.
4320 */
51470298 4321 if (s->got_username && !cfg.change_username) {
5bb641e1 4322 /*
4323 * We got a username last time round this loop, and
4324 * with change_username turned off we don't try to get
4325 * it again.
4326 */
4327 } else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
c0a81592 4328 if (ssh_get_line && !ssh_getline_pw_only) {
32874aea 4329 if (!ssh_get_line("login as: ",
51470298 4330 s->username, sizeof(s->username), FALSE)) {
32874aea 4331 /*
4332 * get_line failed to get a username.
4333 * Terminate.
4334 */
4335 logevent("No username provided. Abandoning session.");
51470298 4336 ssh->state = SSH_STATE_CLOSED;
32874aea 4337 crReturnV;
4338 }
4339 } else {
51470298 4340 int ret; /* need not be saved across crReturn */
4341 c_write_str(ssh, "login as: ");
4342 ssh->send_ok = 1;
4343 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
0405e71f 4344 do {
32874aea 4345 crWaitUntilV(!ispkt);
51470298 4346 ret = process_userpass_input(ssh, in, inlen);
0405e71f 4347 } while (ret == 0);
4348 if (ret < 0)
4349 cleanup_exit(0);
4ca0c9d1 4350 c_write_str(ssh, "\r\n");
32874aea 4351 }
51470298 4352 s->username[strcspn(s->username, "\n\r")] = '\0';
7cca0d81 4353 } else {
4354 char stuff[200];
51470298 4355 strncpy(s->username, cfg.username, sizeof(s->username));
4356 s->username[sizeof(s->username)-1] = '\0';
65a22376 4357 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
51470298 4358 sprintf(stuff, "Using username \"%s\".\r\n", s->username);
4359 c_write_str(ssh, stuff);
7cca0d81 4360 }
4361 }
51470298 4362 s->got_username = TRUE;
7cca0d81 4363
65a22376 4364 /*
1408a877 4365 * Send an authentication request using method "none": (a)
4366 * just in case it succeeds, and (b) so that we know what
4367 * authentication methods we can usefully try next.
65a22376 4368 */
51470298 4369 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4370
4371 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4372 ssh2_pkt_addstring(ssh, s->username);
4373 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4374 ssh2_pkt_addstring(ssh, "none"); /* method */
4375 ssh2_pkt_send(ssh);
4376 s->type = AUTH_TYPE_NONE;
4377 s->gotit = FALSE;
4378 s->we_are_in = FALSE;
4379
4380 s->tried_pubkey_config = FALSE;
4381 s->tried_agent = FALSE;
4382 s->tried_keyb_inter = FALSE;
4383 s->kbd_inter_running = FALSE;
396778f1 4384 /* Load the pub half of cfg.keyfile so we notice if it's in Pageant */
4385 if (*cfg.keyfile) {
231ee168 4386 int keytype;
a8327734 4387 logeventf(ssh->frontend,
4388 "Reading private key file \"%.150s\"", cfg.keyfile);
231ee168 4389 keytype = key_type(cfg.keyfile);
51470298 4390 if (keytype == SSH_KEYTYPE_SSH2) {
4391 s->publickey_blob =
4392 ssh2_userkey_loadpub(cfg.keyfile, NULL,
4393 &s->publickey_bloblen);
4394 } else {
231ee168 4395 char msgbuf[256];
a8327734 4396 logeventf(ssh->frontend,
4397 "Unable to use this key file (%s)",
4398 key_type_to_str(keytype));
231ee168 4399 sprintf(msgbuf, "Unable to use key file \"%.150s\" (%s)\r\n",
4400 cfg.keyfile, key_type_to_str(keytype));
51470298 4401 c_write_str(ssh, msgbuf);
4402 s->publickey_blob = NULL;
231ee168 4403 }
396778f1 4404 } else
51470298 4405 s->publickey_blob = NULL;
65a22376 4406
1408a877 4407 while (1) {
4408 /*
4409 * Wait for the result of the last authentication request.
4410 */
51470298 4411 if (!s->gotit)
1408a877 4412 crWaitUntilV(ispkt);
51470298 4413 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
32874aea 4414 char *banner;
4415 int size;
4416 /*
4417 * Don't show the banner if we're operating in
4418 * non-verbose non-interactive mode. (It's probably
4419 * a script, which means nobody will read the
4420 * banner _anyway_, and moreover the printing of
4421 * the banner will screw up processing on the
4422 * output of (say) plink.)
4423 */
4424 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
51470298 4425 ssh2_pkt_getstring(ssh, &banner, &size);
32874aea 4426 if (banner)
51470298 4427 c_write_untrusted(ssh, banner, size);
32874aea 4428 }
1408a877 4429 crWaitUntilV(ispkt);
4430 }
51470298 4431 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
1408a877 4432 logevent("Access granted");
51470298 4433 s->we_are_in = TRUE;
1408a877 4434 break;
4435 }
65a22376 4436
51470298 4437 if (s->kbd_inter_running &&
4438 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
b3186d64 4439 /*
45068b27 4440 * This is either a further set-of-prompts packet
4441 * in keyboard-interactive authentication, or it's
4442 * the same one and we came back here with `gotit'
4443 * set. In the former case, we must reset the
4444 * curr_prompt variable.
b3186d64 4445 */
51470298 4446 if (!s->gotit)
4447 s->curr_prompt = 0;
4448 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
a8327734 4449 bombout((ssh,"Strange packet received during authentication: type %d",
51470298 4450 ssh->pktin.type));
38c4a8da 4451 crReturnV;
65a22376 4452 }
4453
51470298 4454 s->gotit = FALSE;
65a22376 4455
1408a877 4456 /*
4457 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4458 * we can look at the string in it and know what we can
4459 * helpfully try next.
4460 */
51470298 4461 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
1408a877 4462 char *methods;
4463 int methlen;
51470298 4464 ssh2_pkt_getstring(ssh, &methods, &methlen);
4465 s->kbd_inter_running = FALSE;
4466 if (!ssh2_pkt_getbool(ssh)) {
1408a877 4467 /*
4468 * We have received an unequivocal Access
4469 * Denied. This can translate to a variety of
4470 * messages:
4471 *
4472 * - if we'd just tried "none" authentication,
4473 * it's not worth printing anything at all
4474 *
4475 * - if we'd just tried a public key _offer_,
4476 * the message should be "Server refused our
4477 * key" (or no message at all if the key
4478 * came from Pageant)
4479 *
4480 * - if we'd just tried anything else, the
4481 * message really should be "Access denied".
4482 *
4483 * Additionally, if we'd just tried password
4484 * authentication, we should break out of this
4485 * whole loop so as to go back to the username
4486 * prompt.
4487 */
51470298 4488 if (s->type == AUTH_TYPE_NONE) {
1408a877 4489 /* do nothing */
51470298 4490 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4491 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4492 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4493 c_write_str(ssh, "Server refused our key\r\n");
1408a877 4494 logevent("Server refused public key");
51470298 4495 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4bdf7c46 4496 /* server declined keyboard-interactive; ignore */
1408a877 4497 } else {
51470298 4498 c_write_str(ssh, "Access denied\r\n");
1408a877 4499 logevent("Access denied");
51470298 4500 if (s->type == AUTH_TYPE_PASSWORD) {
4501 s->we_are_in = FALSE;
1408a877 4502 break;
4503 }
4504 }
4505 } else {
51470298 4506 c_write_str(ssh, "Further authentication required\r\n");
1408a877 4507 logevent("Further authentication required");
4508 }
65a22376 4509
51470298 4510 s->can_pubkey =
32874aea 4511 in_commasep_string("publickey", methods, methlen);
51470298 4512 s->can_passwd =
32874aea 4513 in_commasep_string("password", methods, methlen);
51470298 4514 s->can_keyb_inter = cfg.try_ki_auth &&
761187b6 4515 in_commasep_string("keyboard-interactive", methods, methlen);
1408a877 4516 }
65a22376 4517
51470298 4518 s->method = 0;
4519 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
65a22376 4520
0405e71f 4521 /*
4522 * Most password/passphrase prompts will be
4523 * non-echoing, so we set this to 0 by default.
4524 * Exception is that some keyboard-interactive prompts
4525 * can be echoing, in which case we'll set this to 1.
4526 */
51470298 4527 s->echo = 0;
0405e71f 4528
51470298 4529 if (!s->method && s->can_pubkey &&
4530 agent_exists() && !s->tried_agent) {
1983e559 4531 /*
4532 * Attempt public-key authentication using Pageant.
4533 */
1983e559 4534 void *r;
51470298 4535 s->authed = FALSE;
1983e559 4536
51470298 4537 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4538 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
00db133f 4539
51470298 4540 s->tried_agent = TRUE;
1983e559 4541
4542 logevent("Pageant is running. Requesting keys.");
4543
4544 /* Request the keys held by the agent. */
51470298 4545 PUT_32BIT(s->request, 1);
4546 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4547 agent_query(s->request, 5, &r, &s->responselen);
4548 s->response = (unsigned char *) r;
4549 if (s->response && s->responselen >= 5 &&
4550 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4551 s->p = s->response + 5;
4552 s->nkeys = GET_32BIT(s->p);
4553 s->p += 4;
32874aea 4554 {
4555 char buf[64];
51470298 4556 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
32874aea 4557 logevent(buf);
4558 }
51470298 4559 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2d466ffd 4560 void *vret;
1983e559 4561
32874aea 4562 {
4563 char buf[64];
51470298 4564 sprintf(buf, "Trying Pageant key #%d", s->keyi);
32874aea 4565 logevent(buf);
4566 }
51470298 4567 s->pklen = GET_32BIT(s->p);
4568 s->p += 4;
4569 if (s->publickey_blob &&
4570 s->pklen == s->publickey_bloblen &&
4571 !memcmp(s->p, s->publickey_blob,
4572 s->publickey_bloblen)) {
396778f1 4573 logevent("This key matches configured key file");
51470298 4574 s->tried_pubkey_config = 1;
396778f1 4575 }
51470298 4576 s->pkblob = s->p;
4577 s->p += s->pklen;
4578 s->alglen = GET_32BIT(s->pkblob);
4579 s->alg = s->pkblob + 4;
4580 s->commentlen = GET_32BIT(s->p);
4581 s->p += 4;
4582 s->commentp = s->p;
4583 s->p += s->commentlen;
4584 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4585 ssh2_pkt_addstring(ssh, s->username);
4586 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4587 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4588 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4589 ssh2_pkt_addstring_start(ssh);
4590 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4591 ssh2_pkt_addstring_start(ssh);
4592 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4593 ssh2_pkt_send(ssh);
1983e559 4594
4595 crWaitUntilV(ispkt);
51470298 4596 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
1983e559 4597 logevent("Key refused");
4598 continue;
4599 }
4600
32874aea 4601 if (flags & FLAG_VERBOSE) {
51470298 4602 c_write_str(ssh, "Authenticating with "
4603 "public key \"");
4604 c_write(ssh, s->commentp, s->commentlen);
4605 c_write_str(ssh, "\" from agent\r\n");
32874aea 4606 }
1983e559 4607
4608 /*
4609 * Server is willing to accept the key.
4610 * Construct a SIGN_REQUEST.
4611 */
51470298 4612 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4613 ssh2_pkt_addstring(ssh, s->username);
4614 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4615 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4616 ssh2_pkt_addbool(ssh, TRUE);
4617 ssh2_pkt_addstring_start(ssh);
4618 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4619 ssh2_pkt_addstring_start(ssh);
4620 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4621
4622 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4623 s->len = 1; /* message type */
4624 s->len += 4 + s->pklen; /* key blob */
4625 s->len += 4 + s->siglen; /* data to sign */
4626 s->len += 4; /* flags */
4627 s->agentreq = smalloc(4 + s->len);
4628 PUT_32BIT(s->agentreq, s->len);
4629 s->q = s->agentreq + 4;
4630 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4631 PUT_32BIT(s->q, s->pklen);
4632 s->q += 4;
4633 memcpy(s->q, s->pkblob, s->pklen);
4634 s->q += s->pklen;
4635 PUT_32BIT(s->q, s->siglen);
4636 s->q += 4;
1983e559 4637 /* Now the data to be signed... */
51470298 4638 PUT_32BIT(s->q, 20);
4639 s->q += 4;
4640 memcpy(s->q, ssh->v2_session_id, 20);
4641 s->q += 20;
4642 memcpy(s->q, ssh->pktout.data + 5,
4643 ssh->pktout.length - 5);
4644 s->q += ssh->pktout.length - 5;
1983e559 4645 /* And finally the (zero) flags word. */
51470298 4646 PUT_32BIT(s->q, 0);
4647 agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
4648 s->ret = vret;
4649 sfree(s->agentreq);
4650 if (s->ret) {
4651 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
1983e559 4652 logevent("Sending Pageant's response");
51470298 4653 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4654 s->ret + 9,
4655 GET_32BIT(s->ret + 5));
4656 ssh2_pkt_send(ssh);
4657 s->authed = TRUE;
1983e559 4658 break;
4659 } else {
32874aea 4660 logevent
4661 ("Pageant failed to answer challenge");
51470298 4662 sfree(s->ret);
1983e559 4663 }
4664 }
4665 }
51470298 4666 if (s->authed)
1983e559 4667 continue;
4668 }
4669 }
4670
51470298 4671 if (!s->method && s->can_pubkey && s->publickey_blob
4672 && !s->tried_pubkey_config) {
1408a877 4673 unsigned char *pub_blob;
4674 char *algorithm, *comment;
4675 int pub_blob_len;
65a22376 4676
51470298 4677 s->tried_pubkey_config = TRUE;
65a22376 4678
51470298 4679 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4680 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
00db133f 4681
65a22376 4682 /*
1408a877 4683 * Try the public key supplied in the configuration.
4684 *
4685 * First, offer the public blob to see if the server is
4686 * willing to accept it.
65a22376 4687 */
1408a877 4688 pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
4689 &pub_blob_len);
4690 if (pub_blob) {
51470298 4691 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4692 ssh2_pkt_addstring(ssh, s->username);
4693 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4694 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4695 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4696 ssh2_pkt_addstring(ssh, algorithm);
4697 ssh2_pkt_addstring_start(ssh);
4698 ssh2_pkt_addstring_data(ssh, pub_blob, pub_blob_len);
4699 ssh2_pkt_send(ssh);
32874aea 4700 logevent("Offered public key"); /* FIXME */
1408a877 4701
4702 crWaitUntilV(ispkt);
51470298 4703 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4704 s->gotit = TRUE;
4705 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
32874aea 4706 continue; /* key refused; give up on it */
1408a877 4707 }
65a22376 4708
1408a877 4709 logevent("Offer of public key accepted");
65a22376 4710 /*
1408a877 4711 * Actually attempt a serious authentication using
4712 * the key.
65a22376 4713 */
1408a877 4714 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
51470298 4715 sprintf(s->pwprompt,
32874aea 4716 "Passphrase for key \"%.100s\": ",
4717 comment);
51470298 4718 s->need_pw = TRUE;
1408a877 4719 } else {
51470298 4720 s->need_pw = FALSE;
1408a877 4721 }
51470298 4722 c_write_str(ssh, "Authenticating with public key \"");
4723 c_write_str(ssh, comment);
4724 c_write_str(ssh, "\"\r\n");
4725 s->method = AUTH_PUBLICKEY_FILE;
65a22376 4726 }
1408a877 4727 }
4728
51470298 4729 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4730 s->method = AUTH_KEYBOARD_INTERACTIVE;
4731 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4732 s->tried_keyb_inter = TRUE;
af659722 4733
51470298 4734 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4735 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
00db133f 4736
51470298 4737 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4738 ssh2_pkt_addstring(ssh, s->username);
4739 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4740 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4741 ssh2_pkt_addstring(ssh, ""); /* lang */
4742 ssh2_pkt_addstring(ssh, "");
4743 ssh2_pkt_send(ssh);
af659722 4744
4745 crWaitUntilV(ispkt);
51470298 4746 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4747 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4748 s->gotit = TRUE;
af659722 4749 logevent("Keyboard-interactive authentication refused");
51470298 4750 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
af659722 4751 continue;
4752 }
4753
51470298 4754 s->kbd_inter_running = TRUE;
4755 s->curr_prompt = 0;
af659722 4756 }
4757
51470298 4758 if (s->kbd_inter_running) {
4759 s->method = AUTH_KEYBOARD_INTERACTIVE;
4760 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4761 s->tried_keyb_inter = TRUE;
af659722 4762
51470298 4763 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4764 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
00db133f 4765
51470298 4766 if (s->curr_prompt == 0) {
45068b27 4767 /*
4768 * We've got a fresh USERAUTH_INFO_REQUEST.
4769 * Display header data, and start going through
4770 * the prompts.
4771 */
4772 char *name, *inst, *lang;
4773 int name_len, inst_len, lang_len;
4774
51470298 4775 ssh2_pkt_getstring(ssh, &name, &name_len);
4776 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4777 ssh2_pkt_getstring(ssh, &lang, &lang_len);
45068b27 4778 if (name_len > 0) {
51470298 4779 c_write_untrusted(ssh, name, name_len);
4780 c_write_str(ssh, "\r\n");
45068b27 4781 }
4782 if (inst_len > 0) {
51470298 4783 c_write_untrusted(ssh, inst, inst_len);
4784 c_write_str(ssh, "\r\n");
45068b27 4785 }
51470298 4786 s->num_prompts = ssh2_pkt_getuint32(ssh);
45068b27 4787 }
af659722 4788
45068b27 4789 /*
4790 * If there are prompts remaining in the packet,
4791 * display one and get a response.
4792 */
51470298 4793 if (s->curr_prompt < s->num_prompts) {
45068b27 4794 char *prompt;
4795 int prompt_len;
af659722 4796
51470298 4797 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
45068b27 4798 if (prompt_len > 0) {
51470298 4799 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
4800 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
4801 prompt_len : sizeof(s->pwprompt)-1] = '\0';
45068b27 4802 } else {
51470298 4803 strcpy(s->pwprompt,
45068b27 4804 "<server failed to send prompt>: ");
4805 }
51470298 4806 s->echo = ssh2_pkt_getbool(ssh);
4807 s->need_pw = TRUE;
45068b27 4808 } else
51470298 4809 s->need_pw = FALSE;
af659722 4810 }
4811
51470298 4812 if (!s->method && s->can_passwd) {
4813 s->method = AUTH_PASSWORD;
4814 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4815 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4816 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
4817 ssh->savedhost);
4818 s->need_pw = TRUE;
1408a877 4819 }
4820
51470298 4821 if (s->need_pw) {
fa17a66e 4822 if (ssh_get_line) {
51470298 4823 if (!ssh_get_line(s->pwprompt, s->password,
4824 sizeof(s->password), TRUE)) {
1408a877 4825 /*
fa17a66e 4826 * get_line failed to get a password (for
4827 * example because one was supplied on the
4828 * command line which has already failed to
4829 * work). Terminate.
1408a877 4830 */
51470298 4831 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
4832 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
4833 ssh2_pkt_addstring(ssh, "No more passwords available"
4834 " to try");
4835 ssh2_pkt_addstring(ssh, "en"); /* language tag */
4836 ssh2_pkt_send(ssh);
247308b5 4837 logevent("Unable to authenticate");
a8327734 4838 connection_fatal(ssh->frontend,
4839 "Unable to authenticate");
51470298 4840 ssh->state = SSH_STATE_CLOSED;
1408a877 4841 crReturnV;
4842 }
4843 } else {
51470298 4844 int ret; /* need not be saved across crReturn */
4845 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
4846 ssh->send_ok = 1;
1408a877 4847
51470298 4848 setup_userpass_input(ssh, s->password,
4849 sizeof(s->password), s->echo);
0405e71f 4850 do {
1408a877 4851 crWaitUntilV(!ispkt);
51470298 4852 ret = process_userpass_input(ssh, in, inlen);
0405e71f 4853 } while (ret == 0);
4854 if (ret < 0)
4855 cleanup_exit(0);
51470298 4856 c_write_str(ssh, "\r\n");
65a22376 4857 }
65a22376 4858 }
65a22376 4859
51470298 4860 if (s->method == AUTH_PUBLICKEY_FILE) {
1408a877 4861 /*
4862 * We have our passphrase. Now try the actual authentication.
4863 */
4864 struct ssh2_userkey *key;
65a22376 4865
51470298 4866 key = ssh2_load_userkey(cfg.keyfile, s->password);
1408a877 4867 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4868 if (key == SSH2_WRONG_PASSPHRASE) {
51470298 4869 c_write_str(ssh, "Wrong passphrase\r\n");
4870 s->tried_pubkey_config = FALSE;
1408a877 4871 } else {
51470298 4872 c_write_str(ssh, "Unable to load private key\r\n");
4873 s->tried_pubkey_config = TRUE;
1408a877 4874 }
4875 /* Send a spurious AUTH_NONE to return to the top. */
51470298 4876 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4877 ssh2_pkt_addstring(ssh, s->username);
4878 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4879 ssh2_pkt_addstring(ssh, "none"); /* method */
4880 ssh2_pkt_send(ssh);
4881 s->type = AUTH_TYPE_NONE;
1408a877 4882 } else {
1dd353b5 4883 unsigned char *pkblob, *sigblob, *sigdata;
4884 int pkblob_len, sigblob_len, sigdata_len;
65a22376 4885
1408a877 4886 /*
4887 * We have loaded the private key and the server
4888 * has announced that it's willing to accept it.
4889 * Hallelujah. Generate a signature and send it.
4890 */
51470298 4891 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4892 ssh2_pkt_addstring(ssh, s->username);
4893 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4894 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4895 ssh2_pkt_addbool(ssh, TRUE);
4896 ssh2_pkt_addstring(ssh, key->alg->name);
1dd353b5 4897 pkblob = key->alg->public_blob(key->data, &pkblob_len);
51470298 4898 ssh2_pkt_addstring_start(ssh);
4899 ssh2_pkt_addstring_data(ssh, pkblob, pkblob_len);
1408a877 4900
4901 /*
4902 * The data to be signed is:
4903 *
4904 * string session-id
4905 *
4906 * followed by everything so far placed in the
4907 * outgoing packet.
4908 */
51470298 4909 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
1408a877 4910 sigdata = smalloc(sigdata_len);
4911 PUT_32BIT(sigdata, 20);
51470298 4912 memcpy(sigdata + 4, ssh->v2_session_id, 20);
4913 memcpy(sigdata + 24, ssh->pktout.data + 5,
4914 ssh->pktout.length - 5);
1dd353b5 4915 sigblob = key->alg->sign(key->data, sigdata,
4916 sigdata_len, &sigblob_len);
51470298 4917 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
1dd353b5 4918 sigblob, sigblob_len);
4919 sfree(pkblob);
4920 sfree(sigblob);
1408a877 4921 sfree(sigdata);
4922
51470298 4923 ssh2_pkt_send(ssh);
4924 s->type = AUTH_TYPE_PUBLICKEY;
1408a877 4925 }
51470298 4926 } else if (s->method == AUTH_PASSWORD) {
65a22376 4927 /*
1408a877 4928 * We send the password packet lumped tightly together with
4929 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4930 * string long enough to make the total length of the two
4931 * packets constant. This should ensure that a passive
4932 * listener doing traffic analyis can't work out the length
4933 * of the password.
4934 *
4935 * For this to work, we need an assumption about the
4936 * maximum length of the password packet. I think 256 is
4937 * pretty conservative. Anyone using a password longer than
4938 * that probably doesn't have much to worry about from
4939 * people who find out how long their password is!
65a22376 4940 */
51470298 4941 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4942 ssh2_pkt_addstring(ssh, s->username);
4943 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4944 ssh2_pkt_addstring(ssh, "password");
4945 ssh2_pkt_addbool(ssh, FALSE);
4946 ssh2_pkt_addstring(ssh, s->password);
4947 ssh2_pkt_defer(ssh);
65a22376 4948 /*
1408a877 4949 * We'll include a string that's an exact multiple of the
4950 * cipher block size. If the cipher is NULL for some
4951 * reason, we don't do this trick at all because we gain
4952 * nothing by it.
65a22376 4953 */
51470298 4954 if (ssh->cscipher) {
32874aea 4955 int stringlen, i;
4956
51470298 4957 stringlen = (256 - ssh->deferred_len);
4958 stringlen += ssh->cscipher->blksize - 1;
4959 stringlen -= (stringlen % ssh->cscipher->blksize);
4960 if (ssh->cscomp) {
32874aea 4961 /*
4962 * Temporarily disable actual compression,
4963 * so we can guarantee to get this string
4964 * exactly the length we want it. The
4965 * compression-disabling routine should
4966 * return an integer indicating how many
4967 * bytes we should adjust our string length
4968 * by.
4969 */
5366aed8 4970 stringlen -=
4971 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
32874aea 4972 }
51470298 4973 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
4974 ssh2_pkt_addstring_start(ssh);
6e9e9520 4975 for (i = 0; i < stringlen; i++) {
32874aea 4976 char c = (char) random_byte();
51470298 4977 ssh2_pkt_addstring_data(ssh, &c, 1);
65a22376 4978 }
51470298 4979 ssh2_pkt_defer(ssh);
65a22376 4980 }
51470298 4981 ssh_pkt_defersend(ssh);
0d43337a 4982 logevent("Sent password");
51470298 4983 s->type = AUTH_TYPE_PASSWORD;
4984 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
4985 if (s->curr_prompt == 0) {
4986 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
4987 ssh2_pkt_adduint32(ssh, s->num_prompts);
45068b27 4988 }
51470298 4989 if (s->need_pw) { /* only add pw if we just got one! */
4990 ssh2_pkt_addstring(ssh, s->password);
4991 memset(s->password, 0, sizeof(s->password));
4992 s->curr_prompt++;
45068b27 4993 }
51470298 4994 if (s->curr_prompt >= s->num_prompts) {
4995 ssh2_pkt_send(ssh);
45068b27 4996 } else {
4997 /*
4998 * If there are prompts remaining, we set
4999 * `gotit' so that we won't attempt to get
5000 * another packet. Then we go back round the
5001 * loop and will end up retrieving another
5002 * prompt out of the existing packet. Funky or
5003 * what?
5004 */
51470298 5005 s->gotit = TRUE;
45068b27 5006 }
51470298 5007 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
1408a877 5008 } else {
51470298 5009 c_write_str(ssh, "No supported authentication methods"
5010 " left to try!\r\n");
5011 logevent("No supported authentications offered."
5012 " Disconnecting");
5013 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5014 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5015 ssh2_pkt_addstring(ssh, "No supported authentication"
5016 " methods available");
5017 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5018 ssh2_pkt_send(ssh);
5019 ssh->state = SSH_STATE_CLOSED;
1408a877 5020 crReturnV;
65a22376 5021 }
65a22376 5022 }
51470298 5023 } while (!s->we_are_in);
7cca0d81 5024
5025 /*
5026 * Now we're authenticated for the connection protocol. The
5027 * connection protocol will automatically have started at this
5028 * point; there's no need to send SERVICE_REQUEST.
5029 */
5030
5031 /*
5032 * So now create a channel with a session in it.
5033 */
51470298 5034 ssh->channels = newtree234(ssh_channelcmp);
5035 ssh->mainchan = smalloc(sizeof(struct ssh_channel));
5036 ssh->mainchan->ssh = ssh;
5037 ssh->mainchan->localid = alloc_channel_id(ssh);
5038 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5039 ssh2_pkt_addstring(ssh, "session");
5040 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5041 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5042 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5043 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5044 ssh2_pkt_send(ssh);
7cca0d81 5045 crWaitUntilV(ispkt);
51470298 5046 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
a8327734 5047 bombout((ssh,"Server refused to open a session"));
32874aea 5048 crReturnV;
5049 /* FIXME: error data comes back in FAILURE packet */
7cca0d81 5050 }
51470298 5051 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
a8327734 5052 bombout((ssh,"Server's channel confirmation cited wrong channel"));
32874aea 5053 crReturnV;
7cca0d81 5054 }
51470298 5055 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5056 ssh->mainchan->type = CHAN_MAINSESSION;
5057 ssh->mainchan->closes = 0;
5058 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5059 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5060 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5061 add234(ssh->channels, ssh->mainchan);
7cca0d81 5062 logevent("Opened channel for session");
5063
5064 /*
783415f8 5065 * Potentially enable X11 forwarding.
5066 */
5067 if (cfg.x11_forward) {
32874aea 5068 char proto[20], data[64];
5069 logevent("Requesting X11 forwarding");
302121de 5070 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5071 data, sizeof(data));
51470298 5072 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5073 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5074 ssh2_pkt_addstring(ssh, "x11-req");
5075 ssh2_pkt_addbool(ssh, 1); /* want reply */
5076 ssh2_pkt_addbool(ssh, 0); /* many connections */
5077 ssh2_pkt_addstring(ssh, proto);
5078 ssh2_pkt_addstring(ssh, data);
5079 ssh2_pkt_adduint32(ssh, 0); /* screen number */
5080 ssh2_pkt_send(ssh);
32874aea 5081
5082 do {
5083 crWaitUntilV(ispkt);
51470298 5084 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5085 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5086 struct ssh_channel *c;
51470298 5087 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5088 if (!c)
5089 continue; /* nonexistent channel */
51470298 5090 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
32874aea 5091 }
51470298 5092 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
32874aea 5093
51470298 5094 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5095 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
a8327734 5096 bombout((ssh,"Unexpected response to X11 forwarding request:"
51470298 5097 " packet type %d", ssh->pktin.type));
32874aea 5098 crReturnV;
5099 }
5100 logevent("X11 forwarding refused");
5101 } else {
5102 logevent("X11 forwarding enabled");
51470298 5103 ssh->X11_fwd_enabled = TRUE;
32874aea 5104 }
783415f8 5105 }
5106
5107 /*
bc240b21 5108 * Enable port forwardings.
5109 */
5110 {
bc240b21 5111 char type;
5112 int n;
a4fc0d74 5113 int sport,dport,sserv,dserv;
bc240b21 5114 char sports[256], dports[256], host[256];
5115 char buf[1024];
5116
51470298 5117 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
bc240b21 5118 /* Add port forwardings. */
51470298 5119 ssh->portfwd_strptr = cfg.portfwd;
5120 while (*ssh->portfwd_strptr) {
5121 type = *ssh->portfwd_strptr++;
bc240b21 5122 n = 0;
51470298 5123 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t')
5124 sports[n++] = *ssh->portfwd_strptr++;
bc240b21 5125 sports[n] = 0;
51470298 5126 if (*ssh->portfwd_strptr == '\t')
5127 ssh->portfwd_strptr++;
bc240b21 5128 n = 0;
51470298 5129 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':')
5130 host[n++] = *ssh->portfwd_strptr++;
bc240b21 5131 host[n] = 0;
51470298 5132 if (*ssh->portfwd_strptr == ':')
5133 ssh->portfwd_strptr++;
bc240b21 5134 n = 0;
51470298 5135 while (*ssh->portfwd_strptr)
5136 dports[n++] = *ssh->portfwd_strptr++;
bc240b21 5137 dports[n] = 0;
51470298 5138 ssh->portfwd_strptr++;
bc240b21 5139 dport = atoi(dports);
a4fc0d74 5140 dserv = 0;
5141 if (dport == 0) {
5142 dserv = 1;
68a49acb 5143 dport = net_service_lookup(dports);
5144 if (!dport) {
a4fc0d74 5145 sprintf(buf,
5146 "Service lookup failed for destination port \"%s\"",
5147 dports);
5148 logevent(buf);
5149 }
5150 }
bc240b21 5151 sport = atoi(sports);
a4fc0d74 5152 sserv = 0;
5153 if (sport == 0) {
5154 sserv = 1;
68a49acb 5155 sport = net_service_lookup(sports);
5156 if (!sport) {
a4fc0d74 5157 sprintf(buf,
5158 "Service lookup failed for source port \"%s\"",
5159 sports);
5160 logevent(buf);
5161 }
5162 }
bc240b21 5163 if (sport && dport) {
5164 if (type == 'L') {
6b78788a 5165 pfd_addforward(host, dport, sport, ssh);
a4fc0d74 5166 sprintf(buf, "Local port %.*s%.*s%d%.*s forwarding to"
5167 " %s:%.*s%.*s%d%.*s",
68a49acb 5168 (int)(sserv ? strlen(sports) : 0), sports,
a4fc0d74 5169 sserv, "(", sport, sserv, ")",
5170 host,
68a49acb 5171 (int)(dserv ? strlen(dports) : 0), dports,
a4fc0d74 5172 dserv, "(", dport, dserv, ")");
bc240b21 5173 logevent(buf);
5174 } else {
5175 struct ssh_rportfwd *pf;
5176 pf = smalloc(sizeof(*pf));
5177 strcpy(pf->dhost, host);
5178 pf->dport = dport;
5179 pf->sport = sport;
51470298 5180 if (add234(ssh->rportfwds, pf) != pf) {
bc240b21 5181 sprintf(buf,
95bc8819 5182 "Duplicate remote port forwarding to %s:%d",
bc240b21 5183 host, dport);
5184 logevent(buf);
5185 sfree(pf);
5186 } else {
a4fc0d74 5187 sprintf(buf, "Requesting remote port %.*s%.*s%d%.*s"
5188 " forward to %s:%.*s%.*s%d%.*s",
68a49acb 5189 (int)(sserv ? strlen(sports) : 0), sports,
a4fc0d74 5190 sserv, "(", sport, sserv, ")",
5191 host,
68a49acb 5192 (int)(dserv ? strlen(dports) : 0), dports,
a4fc0d74 5193 dserv, "(", dport, dserv, ")");
bc240b21 5194 logevent(buf);
51470298 5195 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5196 ssh2_pkt_addstring(ssh, "tcpip-forward");
5197 ssh2_pkt_addbool(ssh, 1);/* want reply */
beefa433 5198 if (cfg.rport_acceptall)
51470298 5199 ssh2_pkt_addstring(ssh, "0.0.0.0");
beefa433 5200 else
51470298 5201 ssh2_pkt_addstring(ssh, "127.0.0.1");
5202 ssh2_pkt_adduint32(ssh, sport);
5203 ssh2_pkt_send(ssh);
bc240b21 5204
5205 do {
5206 crWaitUntilV(ispkt);
51470298 5207 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5208 unsigned i = ssh2_pkt_getuint32(ssh);
bc240b21 5209 struct ssh_channel *c;
51470298 5210 c = find234(ssh->channels, &i, ssh_channelfind);
bc240b21 5211 if (!c)
5212 continue;/* nonexistent channel */
51470298 5213 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
bc240b21 5214 }
51470298 5215 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
bc240b21 5216
51470298 5217 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5218 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
a8327734 5219 bombout((ssh,"Unexpected response to port "
c9886e66 5220 "forwarding request: packet type %d",
51470298 5221 ssh->pktin.type));
bc240b21 5222 crReturnV;
5223 }
5224 logevent("Server refused this port forwarding");
5225 } else {
5226 logevent("Remote port forwarding enabled");
5227 }
5228 }
5229 }
5230 }
5231 }
5232 }
5233
5234 /*
36c2a3e9 5235 * Potentially enable agent forwarding.
5236 */
5237 if (cfg.agentfwd && agent_exists()) {
32874aea 5238 logevent("Requesting OpenSSH-style agent forwarding");
51470298 5239 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5240 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5241 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5242 ssh2_pkt_addbool(ssh, 1); /* want reply */
5243 ssh2_pkt_send(ssh);
32874aea 5244
5245 do {
5246 crWaitUntilV(ispkt);
51470298 5247 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5248 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5249 struct ssh_channel *c;
51470298 5250 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5251 if (!c)
5252 continue; /* nonexistent channel */
51470298 5253 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
32874aea 5254 }
51470298 5255 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
32874aea 5256
51470298 5257 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5258 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
a8327734 5259 bombout((ssh,"Unexpected response to agent forwarding request:"
51470298 5260 " packet type %d", ssh->pktin.type));
32874aea 5261 crReturnV;
5262 }
5263 logevent("Agent forwarding refused");
5264 } else {
5265 logevent("Agent forwarding enabled");
51470298 5266 ssh->agentfwd_enabled = TRUE;
32874aea 5267 }
36c2a3e9 5268 }
5269
5270 /*
7cca0d81 5271 * Now allocate a pty for the session.
5272 */
67779be7 5273 if (!cfg.nopty) {
51470298 5274 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5275 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5276 ssh2_pkt_addstring(ssh, "pty-req");
5277 ssh2_pkt_addbool(ssh, 1); /* want reply */
5278 ssh2_pkt_addstring(ssh, cfg.termtype);
5279 ssh2_pkt_adduint32(ssh, ssh->term_width);
5280 ssh2_pkt_adduint32(ssh, ssh->term_height);
5281 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5282 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5283 ssh2_pkt_addstring_start(ssh);
5284 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5285 ssh2_pkt_send(ssh);
5286 ssh->state = SSH_STATE_INTERMED;
32874aea 5287
5288 do {
5289 crWaitUntilV(ispkt);
51470298 5290 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5291 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5292 struct ssh_channel *c;
51470298 5293 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5294 if (!c)
5295 continue; /* nonexistent channel */
51470298 5296 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
32874aea 5297 }
51470298 5298 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
32874aea 5299
51470298 5300 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5301 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
a8327734 5302 bombout((ssh,"Unexpected response to pty request:"
51470298 5303 " packet type %d", ssh->pktin.type));
32874aea 5304 crReturnV;
5305 }
51470298 5306 c_write_str(ssh, "Server refused to allocate pty\r\n");
5307 ssh->editing = ssh->echoing = 1;
32874aea 5308 } else {
5309 logevent("Allocated pty");
5310 }
0965bee0 5311 } else {
51470298 5312 ssh->editing = ssh->echoing = 1;
7cca0d81 5313 }
5314
5315 /*
fd5e5847 5316 * Start a shell or a remote command. We may have to attempt
5317 * this twice if the config data has provided a second choice
5318 * of command.
7cca0d81 5319 */
fd5e5847 5320 while (1) {
5321 int subsys;
5322 char *cmd;
5323
51470298 5324 if (ssh->fallback_cmd) {
fd5e5847 5325 subsys = cfg.ssh_subsys2;
5326 cmd = cfg.remote_cmd_ptr2;
5327 } else {
5328 subsys = cfg.ssh_subsys;
5329 cmd = cfg.remote_cmd_ptr;
5330 }
5331
51470298 5332 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5333 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
fd5e5847 5334 if (subsys) {
51470298 5335 ssh2_pkt_addstring(ssh, "subsystem");
5336 ssh2_pkt_addbool(ssh, 1); /* want reply */
5337 ssh2_pkt_addstring(ssh, cmd);
fd5e5847 5338 } else if (*cmd) {
51470298 5339 ssh2_pkt_addstring(ssh, "exec");
5340 ssh2_pkt_addbool(ssh, 1); /* want reply */
5341 ssh2_pkt_addstring(ssh, cmd);
fd5e5847 5342 } else {
51470298 5343 ssh2_pkt_addstring(ssh, "shell");
5344 ssh2_pkt_addbool(ssh, 1); /* want reply */
32874aea 5345 }
51470298 5346 ssh2_pkt_send(ssh);
fd5e5847 5347 do {
5348 crWaitUntilV(ispkt);
51470298 5349 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5350 unsigned i = ssh2_pkt_getuint32(ssh);
fd5e5847 5351 struct ssh_channel *c;
51470298 5352 c = find234(ssh->channels, &i, ssh_channelfind);
fd5e5847 5353 if (!c)
5354 continue; /* nonexistent channel */
51470298 5355 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
fd5e5847 5356 }
51470298 5357 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5358 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5359 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
a8327734 5360 bombout((ssh,"Unexpected response to shell/command request:"
51470298 5361 " packet type %d", ssh->pktin.type));
fd5e5847 5362 crReturnV;
5363 }
5364 /*
5365 * We failed to start the command. If this is the
5366 * fallback command, we really are finished; if it's
5367 * not, and if the fallback command exists, try falling
5368 * back to it before complaining.
5369 */
51470298 5370 if (!ssh->fallback_cmd && cfg.remote_cmd_ptr2 != NULL) {
fd5e5847 5371 logevent("Primary command failed; attempting fallback");
51470298 5372 ssh->fallback_cmd = TRUE;
fd5e5847 5373 continue;
5374 }
a8327734 5375 bombout((ssh,"Server refused to start a shell/command"));
32874aea 5376 crReturnV;
fd5e5847 5377 } else {
5378 logevent("Started a shell/command");
32874aea 5379 }
fd5e5847 5380 break;
7cca0d81 5381 }
5382
51470298 5383 ssh->state = SSH_STATE_SESSION;
5384 if (ssh->size_needed)
5385 ssh_size(ssh, ssh->term_width, ssh->term_height);
5386 if (ssh->eof_needed)
5387 ssh_special(ssh, TS_EOF);
6e48c3fe 5388
7cca0d81 5389 /*
5390 * Transfer data!
5391 */
b9d7bcad 5392 if (ssh->ldisc)
5393 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
51470298 5394 ssh->send_ok = 1;
7cca0d81 5395 while (1) {
e5574168 5396 crReturnV;
51470298 5397 s->try_send = FALSE;
7cca0d81 5398 if (ispkt) {
51470298 5399 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5400 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
32874aea 5401 char *data;
5402 int length;
51470298 5403 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5404 struct ssh_channel *c;
51470298 5405 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5406 if (!c)
5407 continue; /* nonexistent channel */
51470298 5408 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5409 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
32874aea 5410 continue; /* extended but not stderr */
51470298 5411 ssh2_pkt_getstring(ssh, &data, &length);
32874aea 5412 if (data) {
5471d09a 5413 int bufsize;
5414 c->v.v2.locwindow -= length;
32874aea 5415 switch (c->type) {
5416 case CHAN_MAINSESSION:
5471d09a 5417 bufsize =
51470298 5418 from_backend(ssh->frontend, ssh->pktin.type ==
5471d09a 5419 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5420 data, length);
32874aea 5421 break;
5422 case CHAN_X11:
5471d09a 5423 bufsize = x11_send(c->u.x11.s, data, length);
32874aea 5424 break;
d74d141c 5425 case CHAN_SOCKDATA:
5471d09a 5426 bufsize = pfd_send(c->u.pfd.s, data, length);
bc240b21 5427 break;
36c2a3e9 5428 case CHAN_AGENT:
32874aea 5429 while (length > 0) {
5430 if (c->u.a.lensofar < 4) {
5431 int l = min(4 - c->u.a.lensofar, length);
5432 memcpy(c->u.a.msglen + c->u.a.lensofar,
5433 data, l);
5434 data += l;
5435 length -= l;
5436 c->u.a.lensofar += l;
5437 }
5438 if (c->u.a.lensofar == 4) {
5439 c->u.a.totallen =
5440 4 + GET_32BIT(c->u.a.msglen);
5441 c->u.a.message = smalloc(c->u.a.totallen);
5442 memcpy(c->u.a.message, c->u.a.msglen, 4);
5443 }
5444 if (c->u.a.lensofar >= 4 && length > 0) {
5445 int l =
5446 min(c->u.a.totallen - c->u.a.lensofar,
5447 length);
5448 memcpy(c->u.a.message + c->u.a.lensofar,
5449 data, l);
5450 data += l;
5451 length -= l;
5452 c->u.a.lensofar += l;
5453 }
5454 if (c->u.a.lensofar == c->u.a.totallen) {
5455 void *reply, *sentreply;
5456 int replylen;
5457 agent_query(c->u.a.message,
5458 c->u.a.totallen, &reply,
5459 &replylen);
5460 if (reply)
5461 sentreply = reply;
5462 else {
5463 /* Fake SSH_AGENT_FAILURE. */
5464 sentreply = "\0\0\0\1\5";
5465 replylen = 5;
5466 }
51470298 5467 ssh2_add_channel_data(c, sentreply, replylen);
5468 s->try_send = TRUE;
32874aea 5469 if (reply)
5470 sfree(reply);
5471 sfree(c->u.a.message);
5472 c->u.a.lensofar = 0;
5473 }
5474 }
5471d09a 5475 bufsize = 0;
32874aea 5476 break;
5477 }
5478 /*
5471d09a 5479 * If we are not buffering too much data,
5480 * enlarge the window again at the remote side.
32874aea 5481 */
5471d09a 5482 if (bufsize < OUR_V2_WINSIZE)
5483 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
32874aea 5484 }
51470298 5485 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5486 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5487 struct ssh_channel *c;
5488
51470298 5489 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5490 if (!c)
5491 continue; /* nonexistent channel */
5492
5493 if (c->type == CHAN_X11) {
5494 /*
5495 * Remote EOF on an X11 channel means we should
5496 * wrap up and close the channel ourselves.
5497 */
5498 x11_close(c->u.x11.s);
5499 sshfwd_close(c);
5500 } else if (c->type == CHAN_AGENT) {
36c2a3e9 5501 sshfwd_close(c);
d74d141c 5502 } else if (c->type == CHAN_SOCKDATA) {
bc240b21 5503 pfd_close(c->u.pfd.s);
5504 sshfwd_close(c);
36c2a3e9 5505 }
51470298 5506 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5507 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5508 struct ssh_channel *c;
5509
51470298 5510 c = find234(ssh->channels, &i, ssh_channelfind);
d0d844c1 5511 if (!c || ((int)c->remoteid) == -1) {
a8327734 5512 bombout((ssh,"Received CHANNEL_CLOSE for %s channel %d\n",
d0d844c1 5513 c ? "half-open" : "nonexistent", i));
5514 }
32874aea 5515 /* Do pre-close processing on the channel. */
5516 switch (c->type) {
5517 case CHAN_MAINSESSION:
5518 break; /* nothing to see here, move along */
5519 case CHAN_X11:
92f157bd 5520 if (c->u.x11.s != NULL)
5521 x11_close(c->u.x11.s);
5522 sshfwd_close(c);
32874aea 5523 break;
5524 case CHAN_AGENT:
92f157bd 5525 sshfwd_close(c);
32874aea 5526 break;
d74d141c 5527 case CHAN_SOCKDATA:
92f157bd 5528 if (c->u.pfd.s != NULL)
5529 pfd_close(c->u.pfd.s);
5530 sshfwd_close(c);
bc240b21 5531 break;
32874aea 5532 }
92f157bd 5533 if (c->closes == 0) {
51470298 5534 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5535 ssh2_pkt_adduint32(ssh, c->remoteid);
5536 ssh2_pkt_send(ssh);
92f157bd 5537 }
51470298 5538 del234(ssh->channels, c);
5471d09a 5539 bufchain_clear(&c->v.v2.outbuffer);
32874aea 5540 sfree(c);
5541
5542 /*
5543 * See if that was the last channel left open.
5544 */
51470298 5545 if (count234(ssh->channels) == 0) {
ca2914d1 5546#if 0
5547 /*
5548 * We used to send SSH_MSG_DISCONNECT here,
5549 * because I'd believed that _every_ conforming
5550 * SSH2 connection had to end with a disconnect
5551 * being sent by at least one side; apparently
5552 * I was wrong and it's perfectly OK to
5553 * unceremoniously slam the connection shut
5554 * when you're done, and indeed OpenSSH feels
5555 * this is more polite than sending a
5556 * DISCONNECT. So now we don't.
5557 */
32874aea 5558 logevent("All channels closed. Disconnecting");
51470298 5559 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5560 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5561 ssh2_pkt_addstring(ssh, "All open channels closed");
5562 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5563 ssh2_pkt_send(ssh);
ca2914d1 5564#endif
51470298 5565 ssh->state = SSH_STATE_CLOSED;
32874aea 5566 crReturnV;
5567 }
5568 continue; /* remote sends close; ignore (FIXME) */
51470298 5569 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5570 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5571 struct ssh_channel *c;
51470298 5572 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5573 if (!c)
5574 continue; /* nonexistent channel */
51470298 5575 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5576 s->try_send = TRUE;
5577 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5578 unsigned i = ssh2_pkt_getuint32(ssh);
bc240b21 5579 struct ssh_channel *c;
51470298 5580 c = find234(ssh->channels, &i, ssh_channelfind);
bc240b21 5581 if (!c)
5582 continue; /* nonexistent channel */
5583 if (c->type != CHAN_SOCKDATA_DORMANT)
5584 continue; /* dunno why they're confirming this */
51470298 5585 c->remoteid = ssh2_pkt_getuint32(ssh);
bc240b21 5586 c->type = CHAN_SOCKDATA;
51470298 5587 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5588 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
4ed34d25 5589 if (c->u.pfd.s)
5590 pfd_confirm(c->u.pfd.s);
5591 if (c->closes) {
5592 /*
5593 * We have a pending close on this channel,
5594 * which we decided on before the server acked
5595 * the channel open. So now we know the
5596 * remoteid, we can close it again.
5597 */
51470298 5598 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5599 ssh2_pkt_adduint32(ssh, c->remoteid);
5600 ssh2_pkt_send(ssh);
4ed34d25 5601 }
51470298 5602 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5603 unsigned i = ssh2_pkt_getuint32(ssh);
724cface 5604 struct ssh_channel *c;
51470298 5605 c = find234(ssh->channels, &i, ssh_channelfind);
724cface 5606 if (!c)
5607 continue; /* nonexistent channel */
5608 if (c->type != CHAN_SOCKDATA_DORMANT)
5609 continue; /* dunno why they're failing this */
5610
5611 logevent("Forwarded connection refused by server");
5612
5613 pfd_close(c->u.pfd.s);
5614
51470298 5615 del234(ssh->channels, c);
724cface 5616 sfree(c);
51470298 5617 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
ebb0a590 5618 unsigned localid;
5619 char *type;
5620 int typelen, want_reply;
5621 struct ssh_channel *c;
5622
51470298 5623 localid = ssh2_pkt_getuint32(ssh);
5624 ssh2_pkt_getstring(ssh, &type, &typelen);
5625 want_reply = ssh2_pkt_getbool(ssh);
ebb0a590 5626
5627 /*
5628 * First, check that the channel exists. Otherwise,
5629 * we can instantly disconnect with a rude message.
5630 */
51470298 5631 c = find234(ssh->channels, &localid, ssh_channelfind);
ebb0a590 5632 if (!c) {
5633 char buf[80];
5634 sprintf(buf, "Received channel request for nonexistent"
5635 " channel %d", localid);
5636 logevent(buf);
51470298 5637 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5638 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5639 ssh2_pkt_addstring(ssh, buf);
5640 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5641 ssh2_pkt_send(ssh);
247308b5 5642 connection_fatal("%s", buf);
51470298 5643 ssh->state = SSH_STATE_CLOSED;
ebb0a590 5644 crReturnV;
5645 }
5646
5647 /*
d8d6c7e5 5648 * Having got the channel number, we now look at
5649 * the request type string to see if it's something
5650 * we recognise.
ebb0a590 5651 */
d8d6c7e5 5652 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
51470298 5653 c == ssh->mainchan) {
d8d6c7e5 5654 /* We recognise "exit-status" on the primary channel. */
5655 char buf[100];
51470298 5656 ssh->exitcode = ssh2_pkt_getuint32(ssh);
d8d6c7e5 5657 sprintf(buf, "Server sent command exit status %d",
51470298 5658 ssh->exitcode);
d8d6c7e5 5659 logevent(buf);
5660 if (want_reply) {
51470298 5661 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5662 ssh2_pkt_adduint32(ssh, c->remoteid);
5663 ssh2_pkt_send(ssh);
d8d6c7e5 5664 }
5665 } else {
5666 /*
5667 * This is a channel request we don't know
5668 * about, so we now either ignore the request
5669 * or respond with CHANNEL_FAILURE, depending
5670 * on want_reply.
5671 */
5672 if (want_reply) {
51470298 5673 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5674 ssh2_pkt_adduint32(ssh, c->remoteid);
5675 ssh2_pkt_send(ssh);
d8d6c7e5 5676 }
ebb0a590 5677 }
51470298 5678 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
697d4856 5679 char *type;
5680 int typelen, want_reply;
5681
51470298 5682 ssh2_pkt_getstring(ssh, &type, &typelen);
5683 want_reply = ssh2_pkt_getbool(ssh);
697d4856 5684
5685 /*
5686 * We currently don't support any global requests
5687 * at all, so we either ignore the request or
5688 * respond with REQUEST_FAILURE, depending on
5689 * want_reply.
5690 */
5691 if (want_reply) {
51470298 5692 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5693 ssh2_pkt_send(ssh);
697d4856 5694 }
51470298 5695 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
32874aea 5696 char *type;
5697 int typelen;
5698 char *error = NULL;
5699 struct ssh_channel *c;
bc240b21 5700 unsigned remid, winsize, pktsize;
51470298 5701 ssh2_pkt_getstring(ssh, &type, &typelen);
32874aea 5702 c = smalloc(sizeof(struct ssh_channel));
51470298 5703 c->ssh = ssh;
32874aea 5704
51470298 5705 remid = ssh2_pkt_getuint32(ssh);
5706 winsize = ssh2_pkt_getuint32(ssh);
5707 pktsize = ssh2_pkt_getuint32(ssh);
bc240b21 5708
32874aea 5709 if (typelen == 3 && !memcmp(type, "x11", 3)) {
51470298 5710 if (!ssh->X11_fwd_enabled)
32874aea 5711 error = "X11 forwarding is not enabled";
302121de 5712 else if (x11_init(&c->u.x11.s, cfg.x11_display, c,
5713 ssh->x11auth) != NULL) {
32874aea 5714 error = "Unable to open an X11 connection";
5715 } else {
5716 c->type = CHAN_X11;
5717 }
bc240b21 5718 } else if (typelen == 15 &&
5719 !memcmp(type, "forwarded-tcpip", 15)) {
5720 struct ssh_rportfwd pf, *realpf;
5721 char *dummy;
5722 int dummylen;
51470298 5723 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5724 pf.sport = ssh2_pkt_getuint32(ssh);
5725 realpf = find234(ssh->rportfwds, &pf, NULL);
bc240b21 5726 if (realpf == NULL) {
5727 error = "Remote port is not recognised";
5728 } else {
5729 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5730 realpf->dport, c);
5731 char buf[1024];
5732 sprintf(buf, "Received remote port open request for %s:%d",
5733 realpf->dhost, realpf->dport);
5734 logevent(buf);
5735 if (e != NULL) {
5736 sprintf(buf, "Port open failed: %s", e);
5737 logevent(buf);
5738 error = "Port open failed";
5739 } else {
5740 logevent("Forwarded port opened successfully");
5741 c->type = CHAN_SOCKDATA;
5742 }
5743 }
32874aea 5744 } else if (typelen == 22 &&
36c2a3e9 5745 !memcmp(type, "auth-agent@openssh.com", 3)) {
51470298 5746 if (!ssh->agentfwd_enabled)
32874aea 5747 error = "Agent forwarding is not enabled";
36c2a3e9 5748 else {
32874aea 5749 c->type = CHAN_AGENT; /* identify channel type */
36c2a3e9 5750 c->u.a.lensofar = 0;
32874aea 5751 }
5752 } else {
5753 error = "Unsupported channel type requested";
5754 }
5755
bc240b21 5756 c->remoteid = remid;
32874aea 5757 if (error) {
51470298 5758 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
5759 ssh2_pkt_adduint32(ssh, c->remoteid);
5760 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
5761 ssh2_pkt_addstring(ssh, error);
5762 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5763 ssh2_pkt_send(ssh);
32874aea 5764 sfree(c);
5765 } else {
51470298 5766 c->localid = alloc_channel_id(ssh);
32874aea 5767 c->closes = 0;
5471d09a 5768 c->v.v2.locwindow = OUR_V2_WINSIZE;
5769 c->v.v2.remwindow = winsize;
5770 c->v.v2.remmaxpkt = pktsize;
5771 bufchain_init(&c->v.v2.outbuffer);
51470298 5772 add234(ssh->channels, c);
5773 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5774 ssh2_pkt_adduint32(ssh, c->remoteid);
5775 ssh2_pkt_adduint32(ssh, c->localid);
5776 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
5777 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5778 ssh2_pkt_send(ssh);
32874aea 5779 }
7cca0d81 5780 } else {
a8327734 5781 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
32874aea 5782 crReturnV;
7cca0d81 5783 }
5784 } else {
32874aea 5785 /*
5786 * We have spare data. Add it to the channel buffer.
5787 */
51470298 5788 ssh2_add_channel_data(ssh->mainchan, in, inlen);
5789 s->try_send = TRUE;
32874aea 5790 }
51470298 5791 if (s->try_send) {
32874aea 5792 int i;
5793 struct ssh_channel *c;
5794 /*
5795 * Try to send data on all channels if we can.
5796 */
51470298 5797 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5471d09a 5798 int bufsize = ssh2_try_send(c);
5799 if (bufsize == 0) {
5800 switch (c->type) {
5801 case CHAN_MAINSESSION:
5802 /* stdin need not receive an unthrottle
5803 * notification since it will be polled */
5804 break;
5805 case CHAN_X11:
5806 x11_unthrottle(c->u.x11.s);
5807 break;
5808 case CHAN_AGENT:
5809 /* agent sockets are request/response and need no
5810 * buffer management */
5811 break;
5812 case CHAN_SOCKDATA:
5813 pfd_unthrottle(c->u.pfd.s);
5814 break;
5815 }
5816 }
5817 }
7cca0d81 5818 }
e5574168 5819 }
5820
5821 crFinishV;
5822}
5823
5824/*
7cca0d81 5825 * Handle the top-level SSH2 protocol.
5826 */
51470298 5827static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
7cca0d81 5828{
51470298 5829 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
32874aea 5830 return;
51470298 5831 do_ssh2_authconn(ssh, in, inlen, ispkt);
7cca0d81 5832}
5833
5834/*
8df7a775 5835 * Called to set up the connection.
374330e2 5836 *
5837 * Returns an error message, or NULL on success.
374330e2 5838 */
51470298 5839static char *ssh_init(void *frontend_handle, void **backend_handle,
887035a5 5840 char *host, int port, char **realhost, int nodelay)
32874aea 5841{
fb09bf1c 5842 char *p;
51470298 5843 Ssh ssh;
5844
5845 ssh = smalloc(sizeof(*ssh));
5846 ssh->s = NULL;
5847 ssh->cipher = NULL;
371e569c 5848 ssh->v1_cipher_ctx = NULL;
0183b242 5849 ssh->crcda_ctx = NULL;
51470298 5850 ssh->cscipher = NULL;
371e569c 5851 ssh->cs_cipher_ctx = NULL;
51470298 5852 ssh->sccipher = NULL;
371e569c 5853 ssh->sc_cipher_ctx = NULL;
51470298 5854 ssh->csmac = NULL;
a8327734 5855 ssh->cs_mac_ctx = NULL;
51470298 5856 ssh->scmac = NULL;
e0e1a00d 5857 ssh->sc_mac_ctx = NULL;
51470298 5858 ssh->cscomp = NULL;
5366aed8 5859 ssh->cs_comp_ctx = NULL;
51470298 5860 ssh->sccomp = NULL;
5366aed8 5861 ssh->sc_comp_ctx = NULL;
51470298 5862 ssh->kex = NULL;
5863 ssh->hostkey = NULL;
5864 ssh->exitcode = -1;
5865 ssh->state = SSH_STATE_PREPACKET;
5866 ssh->size_needed = FALSE;
5867 ssh->eof_needed = FALSE;
b9d7bcad 5868 ssh->ldisc = NULL;
a8327734 5869 ssh->logctx = NULL;
51470298 5870 {
5871 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
5872 ssh->pktin = ssh->pktout = empty;
5873 }
5874 ssh->deferred_send_data = NULL;
5875 ssh->deferred_len = 0;
5876 ssh->deferred_size = 0;
5877 ssh->fallback_cmd = 0;
5878 ssh->pkt_ctx = 0;
302121de 5879 ssh->x11auth = NULL;
be738459 5880 ssh->v1_compressing = FALSE;
51470298 5881 ssh->v2_outgoing_sequence = 0;
5882 ssh->ssh1_rdpkt_crstate = 0;
5883 ssh->ssh2_rdpkt_crstate = 0;
5884 ssh->do_ssh_init_crstate = 0;
5885 ssh->ssh_gotdata_crstate = 0;
5886 ssh->ssh1_protocol_crstate = 0;
5887 ssh->do_ssh1_login_crstate = 0;
5888 ssh->do_ssh2_transport_crstate = 0;
5889 ssh->do_ssh2_authconn_crstate = 0;
5890 ssh->do_ssh_init_state = NULL;
5891 ssh->do_ssh1_login_state = NULL;
5892 ssh->do_ssh2_transport_state = NULL;
5893 ssh->do_ssh2_authconn_state = NULL;
6571dbfd 5894 ssh->mainchan = NULL;
51470298 5895
5896 *backend_handle = ssh;
32874aea 5897
8f203108 5898#ifdef MSCRYPTOAPI
32874aea 5899 if (crypto_startup() == 0)
8f203108 5900 return "Microsoft high encryption pack not installed!";
5901#endif
374330e2 5902
51470298 5903 ssh->frontend = frontend_handle;
5904 ssh->term_width = cfg.width;
5905 ssh->term_height = cfg.height;
887035a5 5906
51470298 5907 ssh->send_ok = 0;
5908 ssh->editing = 0;
5909 ssh->echoing = 0;
5910 ssh->v1_throttle_count = 0;
5911 ssh->overall_bufsize = 0;
5912 ssh->fallback_cmd = 0;
8df7a775 5913
51470298 5914 p = connect_to_host(ssh, host, port, realhost, nodelay);
fb09bf1c 5915 if (p != NULL)
5916 return p;
374330e2 5917
374330e2 5918 return NULL;
5919}
5920
5921/*
374330e2 5922 * Called to send data down the Telnet connection.
5923 */
51470298 5924static int ssh_send(void *handle, char *buf, int len)
32874aea 5925{
51470298 5926 Ssh ssh = (Ssh) handle;
5927
5928 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5471d09a 5929 return 0;
374330e2 5930
51470298 5931 ssh->protocol(ssh, buf, len, 0);
5471d09a 5932
51470298 5933 return ssh_sendbuffer(ssh);
5471d09a 5934}
5935
5936/*
5937 * Called to query the current amount of buffered stdin data.
5938 */
51470298 5939static int ssh_sendbuffer(void *handle)
5471d09a 5940{
51470298 5941 Ssh ssh = (Ssh) handle;
5471d09a 5942 int override_value;
5943
51470298 5944 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5471d09a 5945 return 0;
5946
5947 /*
5948 * If the SSH socket itself has backed up, add the total backup
5949 * size on that to any individual buffer on the stdin channel.
5950 */
5951 override_value = 0;
51470298 5952 if (ssh->throttled_all)
5953 override_value = ssh->overall_bufsize;
5471d09a 5954
51470298 5955 if (ssh->version == 1) {
5471d09a 5956 return override_value;
51470298 5957 } else if (ssh->version == 2) {
5958 if (!ssh->mainchan || ssh->mainchan->closes > 0)
5471d09a 5959 return override_value;
5960 else
51470298 5961 return (override_value +
5962 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
5471d09a 5963 }
5964
5965 return 0;
374330e2 5966}
5967
5968/*
6e48c3fe 5969 * Called to set the size of the window from SSH's POV.
374330e2 5970 */
51470298 5971static void ssh_size(void *handle, int width, int height)
32874aea 5972{
51470298 5973 Ssh ssh = (Ssh) handle;
5974
5975 ssh->term_width = width;
5976 ssh->term_height = height;
f278d6f8 5977
51470298 5978 switch (ssh->state) {
374330e2 5979 case SSH_STATE_BEFORE_SIZE:
3687d221 5980 case SSH_STATE_PREPACKET:
21248260 5981 case SSH_STATE_CLOSED:
374330e2 5982 break; /* do nothing */
5983 case SSH_STATE_INTERMED:
51470298 5984 ssh->size_needed = TRUE; /* buffer for later */
374330e2 5985 break;
5986 case SSH_STATE_SESSION:
32874aea 5987 if (!cfg.nopty) {
51470298 5988 if (ssh->version == 1) {
5989 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
5990 PKT_INT, ssh->term_height,
5991 PKT_INT, ssh->term_width,
32874aea 5992 PKT_INT, 0, PKT_INT, 0, PKT_END);
5993 } else {
51470298 5994 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5995 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5996 ssh2_pkt_addstring(ssh, "window-change");
5997 ssh2_pkt_addbool(ssh, 0);
5998 ssh2_pkt_adduint32(ssh, ssh->term_width);
5999 ssh2_pkt_adduint32(ssh, ssh->term_height);
6000 ssh2_pkt_adduint32(ssh, 0);
6001 ssh2_pkt_adduint32(ssh, 0);
6002 ssh2_pkt_send(ssh);
32874aea 6003 }
6004 }
6005 break;
374330e2 6006 }
6007}
6008
6009/*
6abbf9e3 6010 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6011 * can send an EOF and collect resulting output (e.g. `plink
6012 * hostname sort').
374330e2 6013 */
51470298 6014static void ssh_special(void *handle, Telnet_Special code)
32874aea 6015{
51470298 6016 Ssh ssh = (Ssh) handle;
6017
6abbf9e3 6018 if (code == TS_EOF) {
51470298 6019 if (ssh->state != SSH_STATE_SESSION) {
32874aea 6020 /*
6021 * Buffer the EOF in case we are pre-SESSION, so we can
6022 * send it as soon as we reach SESSION.
6023 */
6024 if (code == TS_EOF)
51470298 6025 ssh->eof_needed = TRUE;
32874aea 6026 return;
6027 }
51470298 6028 if (ssh->version == 1) {
6029 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
32874aea 6030 } else {
51470298 6031 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6032 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6033 ssh2_pkt_send(ssh);
32874aea 6034 }
6035 logevent("Sent EOF message");
ec55b220 6036 } else if (code == TS_PING) {
51470298 6037 if (ssh->state == SSH_STATE_CLOSED
6038 || ssh->state == SSH_STATE_PREPACKET) return;
6039 if (ssh->version == 1) {
6040 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6041 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
32874aea 6042 } else {
51470298 6043 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6044 ssh2_pkt_addstring_start(ssh);
6045 ssh2_pkt_send(ssh);
32874aea 6046 }
6abbf9e3 6047 } else {
32874aea 6048 /* do nothing */
6abbf9e3 6049 }
374330e2 6050}
6051
51470298 6052void *new_sock_channel(void *handle, Socket s)
d74d141c 6053{
51470298 6054 Ssh ssh = (Ssh) handle;
d74d141c 6055 struct ssh_channel *c;
6056 c = smalloc(sizeof(struct ssh_channel));
51470298 6057 c->ssh = ssh;
d74d141c 6058
6059 if (c) {
bc240b21 6060 c->remoteid = -1; /* to be set when open confirmed */
51470298 6061 c->localid = alloc_channel_id(ssh);
d74d141c 6062 c->closes = 0;
bc240b21 6063 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
d74d141c 6064 c->u.pfd.s = s;
013dd8c0 6065 bufchain_init(&c->v.v2.outbuffer);
51470298 6066 add234(ssh->channels, c);
d74d141c 6067 }
6068 return c;
6069}
6070
5471d09a 6071/*
6072 * This is called when stdout/stderr (the entity to which
6073 * from_backend sends data) manages to clear some backlog.
6074 */
51470298 6075void ssh_unthrottle(void *handle, int bufsize)
5471d09a 6076{
51470298 6077 Ssh ssh = (Ssh) handle;
6078 if (ssh->version == 1) {
6079 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6080 ssh->v1_stdout_throttling = 0;
6081 ssh1_throttle(ssh, -1);
5471d09a 6082 }
6083 } else {
51470298 6084 if (ssh->mainchan && ssh->mainchan->closes == 0)
6085 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
5471d09a 6086 }
6087}
6088
6b78788a 6089void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
d74d141c 6090{
6091 struct ssh_channel *c = (struct ssh_channel *)channel;
6b78788a 6092 Ssh ssh = c->ssh;
d74d141c 6093 char buf[1024];
6094
6095 sprintf(buf, "Opening forwarded connection to %.512s:%d", hostname, port);
6096 logevent(buf);
6097
51470298 6098 if (ssh->version == 1) {
6099 send_packet(ssh, SSH1_MSG_PORT_OPEN,
bc240b21 6100 PKT_INT, c->localid,
6101 PKT_STR, hostname,
6102 PKT_INT, port,
6103 //PKT_STR, <org:orgport>,
6104 PKT_END);
6105 } else {
51470298 6106 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6107 ssh2_pkt_addstring(ssh, "direct-tcpip");
6108 ssh2_pkt_adduint32(ssh, c->localid);
5471d09a 6109 c->v.v2.locwindow = OUR_V2_WINSIZE;
51470298 6110 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6111 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6112 ssh2_pkt_addstring(ssh, hostname);
6113 ssh2_pkt_adduint32(ssh, port);
bc240b21 6114 /*
6115 * We make up values for the originator data; partly it's
6116 * too much hassle to keep track, and partly I'm not
6117 * convinced the server should be told details like that
6118 * about my local network configuration.
6119 */
51470298 6120 ssh2_pkt_addstring(ssh, "client-side-connection");
6121 ssh2_pkt_adduint32(ssh, 0);
6122 ssh2_pkt_send(ssh);
bc240b21 6123 }
d74d141c 6124}
6125
6126
51470298 6127static Socket ssh_socket(void *handle)
32874aea 6128{
51470298 6129 Ssh ssh = (Ssh) handle;
6130 return ssh->s;
32874aea 6131}
8ccc75b0 6132
51470298 6133static int ssh_sendok(void *handle)
32874aea 6134{
51470298 6135 Ssh ssh = (Ssh) handle;
6136 return ssh->send_ok;
32874aea 6137}
fb09bf1c 6138
51470298 6139static int ssh_ldisc(void *handle, int option)
32874aea 6140{
51470298 6141 Ssh ssh = (Ssh) handle;
32874aea 6142 if (option == LD_ECHO)
51470298 6143 return ssh->echoing;
32874aea 6144 if (option == LD_EDIT)
51470298 6145 return ssh->editing;
0965bee0 6146 return FALSE;
6147}
6148
b9d7bcad 6149static void ssh_provide_ldisc(void *handle, void *ldisc)
6150{
6151 Ssh ssh = (Ssh) handle;
6152 ssh->ldisc = ldisc;
6153}
6154
a8327734 6155static void ssh_provide_logctx(void *handle, void *logctx)
6156{
6157 Ssh ssh = (Ssh) handle;
6158 ssh->logctx = logctx;
6159}
6160
51470298 6161static int ssh_return_exitcode(void *handle)
6162{
6163 Ssh ssh = (Ssh) handle;
6164 return ssh->exitcode;
6165}
6166
6167/*
6168 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6169 * that fails. This variable is the means by which scp.c can reach
6170 * into the SSH code and find out which one it got.
6171 */
6172extern int ssh_fallback_cmd(void *handle)
d8d6c7e5 6173{
51470298 6174 Ssh ssh = (Ssh) handle;
6175 return ssh->fallback_cmd;
d8d6c7e5 6176}
6177
374330e2 6178Backend ssh_backend = {
6179 ssh_init,
374330e2 6180 ssh_send,
5471d09a 6181 ssh_sendbuffer,
374330e2 6182 ssh_size,
4017be6d 6183 ssh_special,
8ccc75b0 6184 ssh_socket,
d8d6c7e5 6185 ssh_return_exitcode,
97db3be4 6186 ssh_sendok,
0965bee0 6187 ssh_ldisc,
b9d7bcad 6188 ssh_provide_ldisc,
a8327734 6189 ssh_provide_logctx,
5471d09a 6190 ssh_unthrottle,
97db3be4 6191 22
bc240b21 6192};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator