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Wrong length was causing spurious \0 to be sent during SSH negotiation with
[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
57356d63 641#define logevent(s) do { \
642 logevent(ssh->frontend, s); \
643 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) { \
644 fprintf(stderr, "%s\n", s); \
645 fflush(stderr); \
646 } \
647} while (0)
a8327734 648
649/* logevent, only printf-formatted. */
650void logeventf(Ssh ssh, char *fmt, ...)
651{
652 va_list ap;
57356d63 653 char *buf;
a8327734 654
655 va_start(ap, fmt);
57356d63 656 buf = dupvprintf(fmt, ap);
a8327734 657 va_end(ap);
57356d63 658 logevent(buf);
659 if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) {
660 fprintf(stderr, "%s\n", buf);
661 fflush(stderr);
662 }
663 sfree(buf);
a8327734 664}
665
666#define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
667 (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \
668 logeventf msg, connection_fatal msg )
669
32874aea 670static int ssh_channelcmp(void *av, void *bv)
671{
672 struct ssh_channel *a = (struct ssh_channel *) av;
673 struct ssh_channel *b = (struct ssh_channel *) bv;
674 if (a->localid < b->localid)
675 return -1;
676 if (a->localid > b->localid)
677 return +1;
dacbd0e8 678 return 0;
679}
32874aea 680static int ssh_channelfind(void *av, void *bv)
681{
682 unsigned *a = (unsigned *) av;
683 struct ssh_channel *b = (struct ssh_channel *) bv;
684 if (*a < b->localid)
685 return -1;
686 if (*a > b->localid)
687 return +1;
dacbd0e8 688 return 0;
689}
690
bc240b21 691static int ssh_rportcmp_ssh1(void *av, void *bv)
d74d141c 692{
693 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
694 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
695 int i;
bc240b21 696 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
d74d141c 697 return i < 0 ? -1 : +1;
bc240b21 698 if (a->dport > b->dport)
699 return +1;
700 if (a->dport < b->dport)
701 return -1;
702 return 0;
703}
704
705static int ssh_rportcmp_ssh2(void *av, void *bv)
706{
707 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
708 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
cdcbdf3b 709
bc240b21 710 if (a->sport > b->sport)
d74d141c 711 return +1;
bc240b21 712 if (a->sport < b->sport)
713 return -1;
d74d141c 714 return 0;
715}
716
51470298 717static int alloc_channel_id(Ssh ssh)
32874aea 718{
260f3dec 719 const unsigned CHANNEL_NUMBER_OFFSET = 256;
720 unsigned low, high, mid;
d2371c81 721 int tsize;
722 struct ssh_channel *c;
723
724 /*
725 * First-fit allocation of channel numbers: always pick the
726 * lowest unused one. To do this, binary-search using the
727 * counted B-tree to find the largest channel ID which is in a
728 * contiguous sequence from the beginning. (Precisely
729 * everything in that sequence must have ID equal to its tree
730 * index plus CHANNEL_NUMBER_OFFSET.)
731 */
51470298 732 tsize = count234(ssh->channels);
d2371c81 733
32874aea 734 low = -1;
735 high = tsize;
d2371c81 736 while (high - low > 1) {
737 mid = (high + low) / 2;
51470298 738 c = index234(ssh->channels, mid);
d2371c81 739 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
740 low = mid; /* this one is fine */
741 else
742 high = mid; /* this one is past it */
743 }
744 /*
745 * Now low points to either -1, or the tree index of the
746 * largest ID in the initial sequence.
747 */
748 {
749 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
51470298 750 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
d2371c81 751 }
752 return low + 1 + CHANNEL_NUMBER_OFFSET;
753}
754
51470298 755static void c_write(Ssh ssh, char *buf, int len)
32874aea 756{
67779be7 757 if ((flags & FLAG_STDERR)) {
32874aea 758 int i;
759 for (i = 0; i < len; i++)
760 if (buf[i] != '\r')
761 fputc(buf[i], stderr);
fb09bf1c 762 return;
763 }
51470298 764 from_backend(ssh->frontend, 1, buf, len);
3bdaf79d 765}
766
51470298 767static void c_write_untrusted(Ssh ssh, char *buf, int len)
32874aea 768{
a209e957 769 int i;
770 for (i = 0; i < len; i++) {
32874aea 771 if (buf[i] == '\n')
51470298 772 c_write(ssh, "\r\n", 2);
32874aea 773 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
51470298 774 c_write(ssh, buf + i, 1);
a209e957 775 }
776}
777
51470298 778static void c_write_str(Ssh ssh, char *buf)
32874aea 779{
51470298 780 c_write(ssh, buf, strlen(buf));
1408a877 781}
782
fb09bf1c 783/*
784 * Collect incoming data in the incoming packet buffer.
e5574168 785 * Decipher and verify the packet when it is completely read.
786 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
fb09bf1c 787 * Update the *data and *datalen variables.
788 * Return the additional nr of bytes needed, or 0 when
789 * a complete packet is available.
790 */
51470298 791static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
fb09bf1c 792{
51470298 793 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
374330e2 794
51470298 795 crBegin(ssh->ssh1_rdpkt_crstate);
374330e2 796
32874aea 797 next_packet:
37508af4 798
51470298 799 ssh->pktin.type = 0;
800 ssh->pktin.length = 0;
374330e2 801
57476f6b 802 for (st->i = st->len = 0; st->i < 4; st->i++) {
fb09bf1c 803 while ((*datalen) == 0)
32874aea 804 crReturn(4 - st->i);
57476f6b 805 st->len = (st->len << 8) + **data;
fb09bf1c 806 (*data)++, (*datalen)--;
807 }
374330e2 808
57476f6b 809 st->pad = 8 - (st->len % 8);
810 st->biglen = st->len + st->pad;
51470298 811 ssh->pktin.length = st->len - 5;
fb09bf1c 812
51470298 813 if (ssh->pktin.maxlen < st->biglen) {
814 ssh->pktin.maxlen = st->biglen;
815 ssh->pktin.data = srealloc(ssh->pktin.data, st->biglen + APIEXTRA);
fb09bf1c 816 }
374330e2 817
57476f6b 818 st->to_read = st->biglen;
51470298 819 st->p = ssh->pktin.data;
57476f6b 820 while (st->to_read > 0) {
32874aea 821 st->chunk = st->to_read;
fb09bf1c 822 while ((*datalen) == 0)
57476f6b 823 crReturn(st->to_read);
824 if (st->chunk > (*datalen))
825 st->chunk = (*datalen);
826 memcpy(st->p, *data, st->chunk);
827 *data += st->chunk;
828 *datalen -= st->chunk;
829 st->p += st->chunk;
830 st->to_read -= st->chunk;
fb09bf1c 831 }
374330e2 832
0183b242 833 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
834 st->biglen, NULL)) {
a8327734 835 bombout((ssh,"Network attack (CRC compensation) detected!"));
9a3a93a5 836 crReturn(0);
837 }
838
51470298 839 if (ssh->cipher)
371e569c 840 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
374330e2 841
51470298 842 st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
843 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
57476f6b 844 if (st->gotcrc != st->realcrc) {
a8327734 845 bombout((ssh,"Incorrect CRC received on packet"));
32874aea 846 crReturn(0);
fb09bf1c 847 }
572f871e 848
51470298 849 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
4ba9b64b 850
51470298 851 if (ssh->v1_compressing) {
4ba9b64b 852 unsigned char *decompblk;
853 int decomplen;
5366aed8 854 zlib_decompress_block(ssh->sc_comp_ctx,
855 ssh->pktin.body - 1, ssh->pktin.length + 1,
4ba9b64b 856 &decompblk, &decomplen);
857
51470298 858 if (ssh->pktin.maxlen < st->pad + decomplen) {
859 ssh->pktin.maxlen = st->pad + decomplen;
860 ssh->pktin.data = srealloc(ssh->pktin.data,
861 ssh->pktin.maxlen + APIEXTRA);
862 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
4ba9b64b 863 }
864
51470298 865 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
dcbde236 866 sfree(decompblk);
51470298 867 ssh->pktin.length = decomplen - 1;
4ba9b64b 868 }
869
51470298 870 ssh->pktin.type = ssh->pktin.body[-1];
00db133f 871
a8327734 872 if (ssh->logctx)
873 log_packet(ssh->logctx,
874 PKT_INCOMING, ssh->pktin.type,
875 ssh1_pkt_type(ssh->pktin.type),
876 ssh->pktin.body, ssh->pktin.length);
00db133f 877
51470298 878 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
879 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
880 ssh->pktin.type == SSH1_MSG_DEBUG ||
881 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
882 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
883 long stringlen = GET_32BIT(ssh->pktin.body);
884 if (stringlen + 4 != ssh->pktin.length) {
a8327734 885 bombout((ssh,"Received data packet with bogus string length"));
32874aea 886 crReturn(0);
887 }
fb09bf1c 888 }
889
51470298 890 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
fb09bf1c 891 /* log debug message */
eb4504cc 892 char buf[512];
51470298 893 int stringlen = GET_32BIT(ssh->pktin.body);
eb4504cc 894 strcpy(buf, "Remote debug message: ");
895 if (stringlen > 480)
896 stringlen = 480;
51470298 897 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
3d63ca2e 898 buf[8 + stringlen] = '\0';
fb09bf1c 899 logevent(buf);
900 goto next_packet;
51470298 901 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
fb09bf1c 902 /* do nothing */
903 goto next_packet;
904 }
905
51470298 906 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
38c4a8da 907 /* log reason code in disconnect message */
908 char buf[256];
51470298 909 unsigned msglen = GET_32BIT(ssh->pktin.body);
260f3dec 910 unsigned nowlen;
38c4a8da 911 strcpy(buf, "Remote sent disconnect: ");
912 nowlen = strlen(buf);
32874aea 913 if (msglen > sizeof(buf) - nowlen - 1)
914 msglen = sizeof(buf) - nowlen - 1;
51470298 915 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
32874aea 916 buf[nowlen + msglen] = '\0';
247308b5 917 /* logevent(buf); (this is now done within the bombout macro) */
a8327734 918 bombout((ssh,"Server sent disconnect message:\n\"%s\"", buf+nowlen));
e14d0f19 919 crReturn(0);
38c4a8da 920 }
921
fb09bf1c 922 crFinish(0);
923}
924
51470298 925static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
e5574168 926{
51470298 927 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
e5574168 928
51470298 929 crBegin(ssh->ssh2_rdpkt_crstate);
e5574168 930
32874aea 931 next_packet:
51470298 932 ssh->pktin.type = 0;
933 ssh->pktin.length = 0;
934 if (ssh->sccipher)
935 st->cipherblk = ssh->sccipher->blksize;
e5574168 936 else
32874aea 937 st->cipherblk = 8;
960e736a 938 if (st->cipherblk < 8)
32874aea 939 st->cipherblk = 8;
960e736a 940
51470298 941 if (ssh->pktin.maxlen < st->cipherblk) {
942 ssh->pktin.maxlen = st->cipherblk;
943 ssh->pktin.data = srealloc(ssh->pktin.data, st->cipherblk + APIEXTRA);
e5574168 944 }
945
946 /*
947 * Acquire and decrypt the first block of the packet. This will
948 * contain the length and padding details.
949 */
32874aea 950 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
e5574168 951 while ((*datalen) == 0)
32874aea 952 crReturn(st->cipherblk - st->i);
51470298 953 ssh->pktin.data[st->i] = *(*data)++;
32874aea 954 (*datalen)--;
e5574168 955 }
4252c9cc 956
51470298 957 if (ssh->sccipher)
371e569c 958 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
959 ssh->pktin.data, st->cipherblk);
e5574168 960
961 /*
962 * Now get the length and padding figures.
963 */
51470298 964 st->len = GET_32BIT(ssh->pktin.data);
965 st->pad = ssh->pktin.data[4];
e5574168 966
967 /*
717dc483 968 * _Completely_ silly lengths should be stomped on before they
969 * do us any more damage.
970 */
971 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
a8327734 972 bombout((ssh,"Incoming packet was garbled on decryption"));
717dc483 973 crReturn(0);
974 }
975
976 /*
e5574168 977 * This enables us to deduce the payload length.
978 */
960e736a 979 st->payload = st->len - st->pad - 1;
e5574168 980
51470298 981 ssh->pktin.length = st->payload + 5;
e5574168 982
983 /*
984 * So now we can work out the total packet length.
985 */
960e736a 986 st->packetlen = st->len + 4;
51470298 987 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
e5574168 988
989 /*
990 * Adjust memory allocation if packet is too big.
991 */
51470298 992 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
993 ssh->pktin.maxlen = st->packetlen + st->maclen;
994 ssh->pktin.data = srealloc(ssh->pktin.data,
995 ssh->pktin.maxlen + APIEXTRA);
e5574168 996 }
997
998 /*
999 * Read and decrypt the remainder of the packet.
1000 */
32874aea 1001 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
1002 st->i++) {
e5574168 1003 while ((*datalen) == 0)
960e736a 1004 crReturn(st->packetlen + st->maclen - st->i);
51470298 1005 ssh->pktin.data[st->i] = *(*data)++;
32874aea 1006 (*datalen)--;
e5574168 1007 }
1008 /* Decrypt everything _except_ the MAC. */
51470298 1009 if (ssh->sccipher)
371e569c 1010 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1011 ssh->pktin.data + st->cipherblk,
51470298 1012 st->packetlen - st->cipherblk);
e5574168 1013
1014 /*
1015 * Check the MAC.
1016 */
51470298 1017 if (ssh->scmac
e0e1a00d 1018 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
51470298 1019 st->incoming_sequence)) {
a8327734 1020 bombout((ssh,"Incorrect MAC received on packet"));
32874aea 1021 crReturn(0);
8d5de777 1022 }
32874aea 1023 st->incoming_sequence++; /* whether or not we MACed */
e5574168 1024
4ba9b64b 1025 /*
1026 * Decompress packet payload.
1027 */
1028 {
1029 unsigned char *newpayload;
1030 int newlen;
51470298 1031 if (ssh->sccomp &&
5366aed8 1032 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1033 ssh->pktin.data + 5, ssh->pktin.length - 5,
51470298 1034 &newpayload, &newlen)) {
1035 if (ssh->pktin.maxlen < newlen + 5) {
1036 ssh->pktin.maxlen = newlen + 5;
1037 ssh->pktin.data = srealloc(ssh->pktin.data,
1038 ssh->pktin.maxlen + APIEXTRA);
4ba9b64b 1039 }
51470298 1040 ssh->pktin.length = 5 + newlen;
1041 memcpy(ssh->pktin.data + 5, newpayload, newlen);
dcbde236 1042 sfree(newpayload);
4ba9b64b 1043 }
1044 }
1045
51470298 1046 ssh->pktin.savedpos = 6;
1047 ssh->pktin.type = ssh->pktin.data[5];
e5574168 1048
a8327734 1049 if (ssh->logctx)
1050 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1051 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1052 ssh->pktin.data+6, ssh->pktin.length-6);
00db133f 1053
51470298 1054 switch (ssh->pktin.type) {
3d63ca2e 1055 /*
1056 * These packets we must handle instantly.
1057 */
1058 case SSH2_MSG_DISCONNECT:
1059 {
1060 /* log reason code in disconnect message */
57356d63 1061 char *buf;
1062 int nowlen;
51470298 1063 int reason = GET_32BIT(ssh->pktin.data + 6);
1064 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
57356d63 1065
3d63ca2e 1066 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
57356d63 1067 buf = dupprintf("Received disconnect message (%s)",
1068 ssh2_disconnect_reasons[reason]);
3d63ca2e 1069 } else {
57356d63 1070 buf = dupprintf("Received disconnect message (unknown"
1071 " type %d)", reason);
3d63ca2e 1072 }
1073 logevent(buf);
57356d63 1074 sfree(buf);
1075 buf = dupprintf("Disconnection message text: %n%.*s",
33b82b22 1076 &nowlen, msglen, ssh->pktin.data + 14);
3d63ca2e 1077 logevent(buf);
a8327734 1078 bombout((ssh,"Server sent disconnect message\ntype %d (%s):\n\"%s\"",
3d63ca2e 1079 reason,
1080 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1081 ssh2_disconnect_reasons[reason] : "unknown",
1082 buf+nowlen));
57356d63 1083 sfree(buf);
3d63ca2e 1084 crReturn(0);
1085 }
1086 break;
1087 case SSH2_MSG_IGNORE:
1088 goto next_packet;
1089 case SSH2_MSG_DEBUG:
1090 {
1091 /* log the debug message */
1092 char buf[512];
51470298 1093 /* int display = ssh->pktin.body[6]; */
1094 int stringlen = GET_32BIT(ssh->pktin.data+7);
3d63ca2e 1095 int prefix;
1096 strcpy(buf, "Remote debug message: ");
1097 prefix = strlen(buf);
51470298 1098 if (stringlen > (int)(sizeof(buf)-prefix-1))
3d63ca2e 1099 stringlen = sizeof(buf)-prefix-1;
51470298 1100 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
3d63ca2e 1101 buf[prefix + stringlen] = '\0';
1102 logevent(buf);
38c4a8da 1103 }
3d63ca2e 1104 goto next_packet; /* FIXME: print the debug message */
1105
1106 /*
1107 * These packets we need do nothing about here.
1108 */
1109 case SSH2_MSG_UNIMPLEMENTED:
1110 case SSH2_MSG_SERVICE_REQUEST:
1111 case SSH2_MSG_SERVICE_ACCEPT:
1112 case SSH2_MSG_KEXINIT:
1113 case SSH2_MSG_NEWKEYS:
1114 case SSH2_MSG_KEXDH_INIT:
1115 case SSH2_MSG_KEXDH_REPLY:
1116 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1117 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1118 case SSH2_MSG_KEX_DH_GEX_INIT:
1119 case SSH2_MSG_KEX_DH_GEX_REPLY:
1120 case SSH2_MSG_USERAUTH_REQUEST:
1121 case SSH2_MSG_USERAUTH_FAILURE:
1122 case SSH2_MSG_USERAUTH_SUCCESS:
1123 case SSH2_MSG_USERAUTH_BANNER:
1124 case SSH2_MSG_USERAUTH_PK_OK:
1125 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1126 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1127 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1128 case SSH2_MSG_GLOBAL_REQUEST:
1129 case SSH2_MSG_REQUEST_SUCCESS:
1130 case SSH2_MSG_REQUEST_FAILURE:
1131 case SSH2_MSG_CHANNEL_OPEN:
1132 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1133 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1134 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1135 case SSH2_MSG_CHANNEL_DATA:
1136 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1137 case SSH2_MSG_CHANNEL_EOF:
1138 case SSH2_MSG_CHANNEL_CLOSE:
1139 case SSH2_MSG_CHANNEL_REQUEST:
1140 case SSH2_MSG_CHANNEL_SUCCESS:
1141 case SSH2_MSG_CHANNEL_FAILURE:
1142 break;
1143
1144 /*
1145 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1146 */
1147 default:
51470298 1148 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1149 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1150 ssh2_pkt_send(ssh);
3d63ca2e 1151 break;
38c4a8da 1152 }
1153
e5574168 1154 crFinish(0);
1155}
1156
51470298 1157static void ssh1_pktout_size(Ssh ssh, int len)
32874aea 1158{
374330e2 1159 int pad, biglen;
1160
1161 len += 5; /* type and CRC */
32874aea 1162 pad = 8 - (len % 8);
374330e2 1163 biglen = len + pad;
1164
51470298 1165 ssh->pktout.length = len - 5;
1166 if (ssh->pktout.maxlen < biglen) {
1167 ssh->pktout.maxlen = biglen;
8f203108 1168#ifdef MSCRYPTOAPI
fb09bf1c 1169 /* Allocate enough buffer space for extra block
8f203108 1170 * for MS CryptEncrypt() */
51470298 1171 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 12);
8f203108 1172#else
51470298 1173 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 4);
8f203108 1174#endif
374330e2 1175 }
51470298 1176 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
4ba9b64b 1177}
374330e2 1178
51470298 1179static void s_wrpkt_start(Ssh ssh, int type, int len)
32874aea 1180{
51470298 1181 ssh1_pktout_size(ssh, len);
1182 ssh->pktout.type = type;
374330e2 1183}
1184
51470298 1185static int s_wrpkt_prepare(Ssh ssh)
32874aea 1186{
374330e2 1187 int pad, len, biglen, i;
1188 unsigned long crc;
1189
51470298 1190 ssh->pktout.body[-1] = ssh->pktout.type;
4ba9b64b 1191
a8327734 1192 if (ssh->logctx)
1193 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1194 ssh1_pkt_type(ssh->pktout.type),
1195 ssh->pktout.body, ssh->pktout.length);
00db133f 1196
51470298 1197 if (ssh->v1_compressing) {
4ba9b64b 1198 unsigned char *compblk;
1199 int complen;
5366aed8 1200 zlib_compress_block(ssh->cs_comp_ctx,
1201 ssh->pktout.body - 1, ssh->pktout.length + 1,
4ba9b64b 1202 &compblk, &complen);
51470298 1203 ssh1_pktout_size(ssh, complen - 1);
1204 memcpy(ssh->pktout.body - 1, compblk, complen);
dcbde236 1205 sfree(compblk);
4ba9b64b 1206 }
1207
51470298 1208 len = ssh->pktout.length + 5; /* type and CRC */
32874aea 1209 pad = 8 - (len % 8);
374330e2 1210 biglen = len + pad;
1211
32874aea 1212 for (i = 0; i < pad; i++)
51470298 1213 ssh->pktout.data[i + 4] = random_byte();
1214 crc = crc32(ssh->pktout.data + 4, biglen - 4);
1215 PUT_32BIT(ssh->pktout.data + biglen, crc);
1216 PUT_32BIT(ssh->pktout.data, len);
374330e2 1217
51470298 1218 if (ssh->cipher)
371e569c 1219 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
374330e2 1220
32874aea 1221 return biglen + 4;
39065bed 1222}
1223
51470298 1224static void s_wrpkt(Ssh ssh)
32874aea 1225{
5471d09a 1226 int len, backlog;
51470298 1227 len = s_wrpkt_prepare(ssh);
1228 backlog = sk_write(ssh->s, ssh->pktout.data, len);
5471d09a 1229 if (backlog > SSH_MAX_BACKLOG)
51470298 1230 ssh_throttle_all(ssh, 1, backlog);
39065bed 1231}
1232
51470298 1233static void s_wrpkt_defer(Ssh ssh)
32874aea 1234{
39065bed 1235 int len;
51470298 1236 len = s_wrpkt_prepare(ssh);
1237 if (ssh->deferred_len + len > ssh->deferred_size) {
1238 ssh->deferred_size = ssh->deferred_len + len + 128;
1239 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1240 ssh->deferred_size);
39065bed 1241 }
51470298 1242 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1243 ssh->deferred_len += len;
374330e2 1244}
1245
fb09bf1c 1246/*
39065bed 1247 * Construct a packet with the specified contents.
fb09bf1c 1248 */
51470298 1249static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
fb09bf1c 1250{
fb09bf1c 1251 unsigned char *p, *argp, argchar;
1252 unsigned long argint;
1253 int pktlen, argtype, arglen;
7cca0d81 1254 Bignum bn;
fb09bf1c 1255
1256 pktlen = 0;
39065bed 1257 while ((argtype = va_arg(ap1, int)) != PKT_END) {
fb09bf1c 1258 switch (argtype) {
1259 case PKT_INT:
39065bed 1260 (void) va_arg(ap1, int);
fb09bf1c 1261 pktlen += 4;
1262 break;
1263 case PKT_CHAR:
1ec39246 1264 (void) va_arg(ap1, int);
fb09bf1c 1265 pktlen++;
1266 break;
1267 case PKT_DATA:
39065bed 1268 (void) va_arg(ap1, unsigned char *);
1269 arglen = va_arg(ap1, int);
fb09bf1c 1270 pktlen += arglen;
1271 break;
1272 case PKT_STR:
39065bed 1273 argp = va_arg(ap1, unsigned char *);
fb09bf1c 1274 arglen = strlen(argp);
1275 pktlen += 4 + arglen;
1276 break;
7cca0d81 1277 case PKT_BIGNUM:
39065bed 1278 bn = va_arg(ap1, Bignum);
32874aea 1279 pktlen += ssh1_bignum_length(bn);
7cca0d81 1280 break;
fb09bf1c 1281 default:
1282 assert(0);
1283 }
1284 }
fb09bf1c 1285
51470298 1286 s_wrpkt_start(ssh, pkttype, pktlen);
1287 p = ssh->pktout.body;
fb09bf1c 1288
39065bed 1289 while ((argtype = va_arg(ap2, int)) != PKT_END) {
fb09bf1c 1290 switch (argtype) {
1291 case PKT_INT:
39065bed 1292 argint = va_arg(ap2, int);
fb09bf1c 1293 PUT_32BIT(p, argint);
1294 p += 4;
1295 break;
1296 case PKT_CHAR:
1ec39246 1297 argchar = (unsigned char) va_arg(ap2, int);
fb09bf1c 1298 *p = argchar;
1299 p++;
1300 break;
1301 case PKT_DATA:
39065bed 1302 argp = va_arg(ap2, unsigned char *);
1303 arglen = va_arg(ap2, int);
fb09bf1c 1304 memcpy(p, argp, arglen);
1305 p += arglen;
1306 break;
1307 case PKT_STR:
39065bed 1308 argp = va_arg(ap2, unsigned char *);
fb09bf1c 1309 arglen = strlen(argp);
1310 PUT_32BIT(p, arglen);
1311 memcpy(p + 4, argp, arglen);
1312 p += 4 + arglen;
1313 break;
7cca0d81 1314 case PKT_BIGNUM:
39065bed 1315 bn = va_arg(ap2, Bignum);
32874aea 1316 p += ssh1_write_bignum(p, bn);
7cca0d81 1317 break;
fb09bf1c 1318 }
1319 }
39065bed 1320}
fb09bf1c 1321
51470298 1322static void send_packet(Ssh ssh, int pkttype, ...)
32874aea 1323{
39065bed 1324 va_list ap1, ap2;
1325 va_start(ap1, pkttype);
1326 va_start(ap2, pkttype);
51470298 1327 construct_packet(ssh, pkttype, ap1, ap2);
1328 s_wrpkt(ssh);
fb09bf1c 1329}
1330
51470298 1331static void defer_packet(Ssh ssh, int pkttype, ...)
32874aea 1332{
39065bed 1333 va_list ap1, ap2;
1334 va_start(ap1, pkttype);
1335 va_start(ap2, pkttype);
51470298 1336 construct_packet(ssh, pkttype, ap1, ap2);
1337 s_wrpkt_defer(ssh);
39065bed 1338}
1339
32874aea 1340static int ssh_versioncmp(char *a, char *b)
1341{
9697bfd2 1342 char *ae, *be;
1343 unsigned long av, bv;
1344
43aa02a7 1345 av = strtoul(a, &ae, 10);
1346 bv = strtoul(b, &be, 10);
32874aea 1347 if (av != bv)
1348 return (av < bv ? -1 : +1);
1349 if (*ae == '.')
1350 ae++;
1351 if (*be == '.')
1352 be++;
43aa02a7 1353 av = strtoul(ae, &ae, 10);
1354 bv = strtoul(be, &be, 10);
32874aea 1355 if (av != bv)
1356 return (av < bv ? -1 : +1);
9697bfd2 1357 return 0;
1358}
1359
e5574168 1360/*
a92dd380 1361 * Utility routines for putting an SSH-protocol `string' and
1362 * `uint32' into a SHA state.
e5574168 1363 */
1364#include <stdio.h>
32874aea 1365static void sha_string(SHA_State * s, void *str, int len)
1366{
e5574168 1367 unsigned char lenblk[4];
e5574168 1368 PUT_32BIT(lenblk, len);
e5574168 1369 SHA_Bytes(s, lenblk, 4);
e5574168 1370 SHA_Bytes(s, str, len);
1371}
1372
32874aea 1373static void sha_uint32(SHA_State * s, unsigned i)
1374{
a92dd380 1375 unsigned char intblk[4];
1376 PUT_32BIT(intblk, i);
1377 SHA_Bytes(s, intblk, 4);
1378}
1379
7cca0d81 1380/*
1381 * SSH2 packet construction functions.
1382 */
51470298 1383static void ssh2_pkt_ensure(Ssh ssh, int length)
32874aea 1384{
51470298 1385 if (ssh->pktout.maxlen < length) {
1386 ssh->pktout.maxlen = length + 256;
1387 ssh->pktout.data = srealloc(ssh->pktout.data,
1388 ssh->pktout.maxlen + APIEXTRA);
1389 if (!ssh->pktout.data)
32874aea 1390 fatalbox("Out of memory");
7cca0d81 1391 }
783415f8 1392}
51470298 1393static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
32874aea 1394{
51470298 1395 ssh->pktout.length += len;
1396 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1397 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
7cca0d81 1398}
51470298 1399static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
32874aea 1400{
51470298 1401 ssh2_pkt_adddata(ssh, &byte, 1);
7cca0d81 1402}
51470298 1403static void ssh2_pkt_init(Ssh ssh, int pkt_type)
32874aea 1404{
51470298 1405 ssh->pktout.length = 5;
1406 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
7cca0d81 1407}
51470298 1408static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
32874aea 1409{
51470298 1410 ssh2_pkt_adddata(ssh, &value, 1);
7cca0d81 1411}
51470298 1412static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
32874aea 1413{
7cca0d81 1414 unsigned char x[4];
1415 PUT_32BIT(x, value);
51470298 1416 ssh2_pkt_adddata(ssh, x, 4);
7cca0d81 1417}
51470298 1418static void ssh2_pkt_addstring_start(Ssh ssh)
32874aea 1419{
51470298 1420 ssh2_pkt_adduint32(ssh, 0);
1421 ssh->pktout.savedpos = ssh->pktout.length;
7cca0d81 1422}
51470298 1423static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
32874aea 1424{
51470298 1425 ssh2_pkt_adddata(ssh, data, strlen(data));
1426 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1427 ssh->pktout.length - ssh->pktout.savedpos);
7cca0d81 1428}
51470298 1429static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
32874aea 1430{
51470298 1431 ssh2_pkt_adddata(ssh, data, len);
1432 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1433 ssh->pktout.length - ssh->pktout.savedpos);
7cca0d81 1434}
51470298 1435static void ssh2_pkt_addstring(Ssh ssh, char *data)
32874aea 1436{
51470298 1437 ssh2_pkt_addstring_start(ssh);
1438 ssh2_pkt_addstring_str(ssh, data);
7cca0d81 1439}
32874aea 1440static char *ssh2_mpint_fmt(Bignum b, int *len)
1441{
7cca0d81 1442 unsigned char *p;
32874aea 1443 int i, n = (bignum_bitcount(b) + 7) / 8;
3709bfe9 1444 p = smalloc(n + 1);
7cca0d81 1445 if (!p)
32874aea 1446 fatalbox("out of memory");
7cca0d81 1447 p[0] = 0;
3709bfe9 1448 for (i = 1; i <= n; i++)
32874aea 1449 p[i] = bignum_byte(b, n - i);
7cca0d81 1450 i = 0;
32874aea 1451 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1452 i++;
1453 memmove(p, p + i, n + 1 - i);
1454 *len = n + 1 - i;
7cca0d81 1455 return p;
1456}
51470298 1457static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
32874aea 1458{
7cca0d81 1459 unsigned char *p;
1460 int len;
1461 p = ssh2_mpint_fmt(b, &len);
51470298 1462 ssh2_pkt_addstring_start(ssh);
1463 ssh2_pkt_addstring_data(ssh, p, len);
dcbde236 1464 sfree(p);
7cca0d81 1465}
b185170a 1466
1467/*
1468 * Construct an SSH2 final-form packet: compress it, encrypt it,
1469 * put the MAC on it. Final packet, ready to be sent, is stored in
51470298 1470 * ssh->pktout.data. Total length is returned.
b185170a 1471 */
51470298 1472static int ssh2_pkt_construct(Ssh ssh)
32874aea 1473{
7cca0d81 1474 int cipherblk, maclen, padding, i;
7cca0d81 1475
a8327734 1476 if (ssh->logctx)
1477 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1478 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1479 ssh->pktout.data + 6, ssh->pktout.length - 6);
00db133f 1480
7cca0d81 1481 /*
4ba9b64b 1482 * Compress packet payload.
1483 */
4ba9b64b 1484 {
1485 unsigned char *newpayload;
1486 int newlen;
51470298 1487 if (ssh->cscomp &&
5366aed8 1488 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1489 ssh->pktout.length - 5,
51470298 1490 &newpayload, &newlen)) {
1491 ssh->pktout.length = 5;
1492 ssh2_pkt_adddata(ssh, newpayload, newlen);
dcbde236 1493 sfree(newpayload);
4ba9b64b 1494 }
1495 }
1496
1497 /*
7cca0d81 1498 * Add padding. At least four bytes, and must also bring total
1499 * length (minus MAC) up to a multiple of the block size.
1500 */
51470298 1501 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
32874aea 1502 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
7cca0d81 1503 padding = 4;
32874aea 1504 padding +=
51470298 1505 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1506 maclen = ssh->csmac ? ssh->csmac->len : 0;
1507 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1508 ssh->pktout.data[4] = padding;
7cca0d81 1509 for (i = 0; i < padding; i++)
51470298 1510 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1511 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1512 if (ssh->csmac)
e0e1a00d 1513 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1514 ssh->pktout.length + padding,
51470298 1515 ssh->v2_outgoing_sequence);
1516 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1517
1518 if (ssh->cscipher)
371e569c 1519 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1520 ssh->pktout.data, ssh->pktout.length + padding);
51470298 1521
1522 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1523 return ssh->pktout.length + padding + maclen;
b185170a 1524}
1525
1526/*
1527 * Construct and send an SSH2 packet immediately.
1528 */
51470298 1529static void ssh2_pkt_send(Ssh ssh)
32874aea 1530{
5471d09a 1531 int len;
1532 int backlog;
51470298 1533 len = ssh2_pkt_construct(ssh);
1534 backlog = sk_write(ssh->s, ssh->pktout.data, len);
5471d09a 1535 if (backlog > SSH_MAX_BACKLOG)
51470298 1536 ssh_throttle_all(ssh, 1, backlog);
b185170a 1537}
1538
1539/*
1540 * Construct an SSH2 packet and add it to a deferred data block.
1541 * Useful for sending multiple packets in a single sk_write() call,
1542 * to prevent a traffic-analysing listener from being able to work
1543 * out the length of any particular packet (such as the password
1544 * packet).
1545 *
1546 * Note that because SSH2 sequence-numbers its packets, this can
1547 * NOT be used as an m4-style `defer' allowing packets to be
1548 * constructed in one order and sent in another.
1549 */
51470298 1550static void ssh2_pkt_defer(Ssh ssh)
32874aea 1551{
51470298 1552 int len = ssh2_pkt_construct(ssh);
1553 if (ssh->deferred_len + len > ssh->deferred_size) {
1554 ssh->deferred_size = ssh->deferred_len + len + 128;
1555 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1556 ssh->deferred_size);
b185170a 1557 }
51470298 1558 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1559 ssh->deferred_len += len;
b185170a 1560}
1561
1562/*
1563 * Send the whole deferred data block constructed by
39065bed 1564 * ssh2_pkt_defer() or SSH1's defer_packet().
b185170a 1565 */
51470298 1566static void ssh_pkt_defersend(Ssh ssh)
32874aea 1567{
5471d09a 1568 int backlog;
51470298 1569 backlog = sk_write(ssh->s, ssh->deferred_send_data, ssh->deferred_len);
1570 ssh->deferred_len = ssh->deferred_size = 0;
1571 sfree(ssh->deferred_send_data);
1572 ssh->deferred_send_data = NULL;
5471d09a 1573 if (backlog > SSH_MAX_BACKLOG)
51470298 1574 ssh_throttle_all(ssh, 1, backlog);
7cca0d81 1575}
1576
1577#if 0
32874aea 1578void bndebug(char *string, Bignum b)
1579{
7cca0d81 1580 unsigned char *p;
1581 int i, len;
1582 p = ssh2_mpint_fmt(b, &len);
1583 debug(("%s", string));
1584 for (i = 0; i < len; i++)
32874aea 1585 debug((" %02x", p[i]));
765c4200 1586 debug(("\n"));
dcbde236 1587 sfree(p);
7cca0d81 1588}
1589#endif
1590
32874aea 1591static void sha_mpint(SHA_State * s, Bignum b)
1592{
7cca0d81 1593 unsigned char *p;
1594 int len;
1595 p = ssh2_mpint_fmt(b, &len);
1596 sha_string(s, p, len);
dcbde236 1597 sfree(p);
7cca0d81 1598}
1599
1600/*
1601 * SSH2 packet decode functions.
1602 */
51470298 1603static unsigned long ssh2_pkt_getuint32(Ssh ssh)
32874aea 1604{
7cca0d81 1605 unsigned long value;
51470298 1606 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
32874aea 1607 return 0; /* arrgh, no way to decline (FIXME?) */
51470298 1608 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1609 ssh->pktin.savedpos += 4;
7cca0d81 1610 return value;
1611}
51470298 1612static int ssh2_pkt_getbool(Ssh ssh)
32874aea 1613{
65a22376 1614 unsigned long value;
51470298 1615 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
32874aea 1616 return 0; /* arrgh, no way to decline (FIXME?) */
51470298 1617 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1618 ssh->pktin.savedpos++;
65a22376 1619 return value;
1620}
51470298 1621static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
32874aea 1622{
57356d63 1623 int len;
7cca0d81 1624 *p = NULL;
45068b27 1625 *length = 0;
51470298 1626 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
32874aea 1627 return;
57356d63 1628 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1629 if (len < 0)
1630 return;
1631 *length = len;
51470298 1632 ssh->pktin.savedpos += 4;
1633 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
32874aea 1634 return;
51470298 1635 *p = ssh->pktin.data + ssh->pktin.savedpos;
1636 ssh->pktin.savedpos += *length;
7cca0d81 1637}
51470298 1638static Bignum ssh2_pkt_getmp(Ssh ssh)
32874aea 1639{
7cca0d81 1640 char *p;
3709bfe9 1641 int length;
7cca0d81 1642 Bignum b;
1643
51470298 1644 ssh2_pkt_getstring(ssh, &p, &length);
7cca0d81 1645 if (!p)
32874aea 1646 return NULL;
8d5de777 1647 if (p[0] & 0x80) {
a8327734 1648 bombout((ssh,"internal error: Can't handle negative mpints"));
32874aea 1649 return NULL;
8d5de777 1650 }
3709bfe9 1651 b = bignum_from_bytes(p, length);
7cca0d81 1652 return b;
1653}
1654
7d503c31 1655/*
1dd353b5 1656 * Helper function to add an SSH2 signature blob to a packet.
1657 * Expects to be shown the public key blob as well as the signature
1658 * blob. Normally works just like ssh2_pkt_addstring, but will
1659 * fiddle with the signature packet if necessary for
1660 * BUG_SSH2_RSA_PADDING.
1661 */
51470298 1662static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1dd353b5 1663 void *sigblob_v, int sigblob_len)
1664{
1665 unsigned char *pkblob = (unsigned char *)pkblob_v;
1666 unsigned char *sigblob = (unsigned char *)sigblob_v;
1667
1668 /* dmemdump(pkblob, pkblob_len); */
1669 /* dmemdump(sigblob, sigblob_len); */
1670
1671 /*
1672 * See if this is in fact an ssh-rsa signature and a buggy
1673 * server; otherwise we can just do this the easy way.
1674 */
51470298 1675 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1dd353b5 1676 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1677 int pos, len, siglen;
1678
1679 /*
1680 * Find the byte length of the modulus.
1681 */
1682
1683 pos = 4+7; /* skip over "ssh-rsa" */
1684 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1685 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1686 pos += 4; /* find modulus itself */
1687 while (len > 0 && pkblob[pos] == 0)
1688 len--, pos++;
1689 /* debug(("modulus length is %d\n", len)); */
1690
1691 /*
1692 * Now find the signature integer.
1693 */
1694 pos = 4+7; /* skip over "ssh-rsa" */
1695 siglen = GET_32BIT(sigblob+pos);
1696 /* debug(("signature length is %d\n", siglen)); */
1697
1698 if (len != siglen) {
1699 unsigned char newlen[4];
51470298 1700 ssh2_pkt_addstring_start(ssh);
1701 ssh2_pkt_addstring_data(ssh, sigblob, pos);
1dd353b5 1702 /* dmemdump(sigblob, pos); */
1703 pos += 4; /* point to start of actual sig */
1704 PUT_32BIT(newlen, len);
51470298 1705 ssh2_pkt_addstring_data(ssh, newlen, 4);
1dd353b5 1706 /* dmemdump(newlen, 4); */
1707 newlen[0] = 0;
1708 while (len-- > siglen) {
51470298 1709 ssh2_pkt_addstring_data(ssh, newlen, 1);
1dd353b5 1710 /* dmemdump(newlen, 1); */
1711 }
51470298 1712 ssh2_pkt_addstring_data(ssh, sigblob+pos, siglen);
1dd353b5 1713 /* dmemdump(sigblob+pos, siglen); */
1714 return;
1715 }
1716
1717 /* Otherwise fall through and do it the easy way. */
1718 }
1719
51470298 1720 ssh2_pkt_addstring_start(ssh);
1721 ssh2_pkt_addstring_data(ssh, sigblob, sigblob_len);
1dd353b5 1722}
1723
1724/*
7d503c31 1725 * Examine the remote side's version string and compare it against
1726 * a list of known buggy implementations.
1727 */
51470298 1728static void ssh_detect_bugs(Ssh ssh, char *vstring)
32874aea 1729{
1730 char *imp; /* pointer to implementation part */
7d503c31 1731 imp = vstring;
1732 imp += strcspn(imp, "-");
bd358db1 1733 if (*imp) imp++;
7d503c31 1734 imp += strcspn(imp, "-");
bd358db1 1735 if (*imp) imp++;
7d503c31 1736
51470298 1737 ssh->remote_bugs = 0;
7d503c31 1738
2c9c6388 1739 if (cfg.sshbug_ignore1 == BUG_ON ||
1740 (cfg.sshbug_ignore1 == BUG_AUTO &&
1741 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1742 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1743 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
32874aea 1744 /*
1745 * These versions don't support SSH1_MSG_IGNORE, so we have
1746 * to use a different defence against password length
1747 * sniffing.
1748 */
51470298 1749 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
32874aea 1750 logevent("We believe remote version has SSH1 ignore bug");
7d503c31 1751 }
1752
2c9c6388 1753 if (cfg.sshbug_plainpw1 == BUG_ON ||
1754 (cfg.sshbug_plainpw1 == BUG_AUTO &&
1755 (!strcmp(imp, "Cisco-1.25")))) {
bd358db1 1756 /*
1757 * These versions need a plain password sent; they can't
1758 * handle having a null and a random length of data after
1759 * the password.
1760 */
51470298 1761 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
bd358db1 1762 logevent("We believe remote version needs a plain SSH1 password");
1763 }
1764
2c9c6388 1765 if (cfg.sshbug_rsa1 == BUG_ON ||
1766 (cfg.sshbug_rsa1 == BUG_AUTO &&
1767 (!strcmp(imp, "Cisco-1.25")))) {
0df73905 1768 /*
1769 * These versions apparently have no clue whatever about
1770 * RSA authentication and will panic and die if they see
1771 * an AUTH_RSA message.
1772 */
51470298 1773 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
0df73905 1774 logevent("We believe remote version can't handle RSA authentication");
1775 }
1776
2c9c6388 1777 if (cfg.sshbug_hmac2 == BUG_ON ||
1778 (cfg.sshbug_hmac2 == BUG_AUTO &&
1779 (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
1780 !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
1781 !strncmp(imp, "2.1 ", 4)))) {
32874aea 1782 /*
1783 * These versions have the HMAC bug.
1784 */
51470298 1785 ssh->remote_bugs |= BUG_SSH2_HMAC;
32874aea 1786 logevent("We believe remote version has SSH2 HMAC bug");
7d503c31 1787 }
1dd353b5 1788
2c9c6388 1789 if (cfg.sshbug_derivekey2 == BUG_ON ||
1790 (cfg.sshbug_derivekey2 == BUG_AUTO &&
1791 (!strncmp(imp, "2.0.", 4)))) {
088bde77 1792 /*
1793 * These versions have the key-derivation bug (failing to
1794 * include the literal shared secret in the hashes that
1795 * generate the keys).
1796 */
51470298 1797 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
088bde77 1798 logevent("We believe remote version has SSH2 key-derivation bug");
1799 }
1800
2c9c6388 1801 if (cfg.sshbug_rsapad2 == BUG_ON ||
1802 (cfg.sshbug_rsapad2 == BUG_AUTO &&
1803 ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') ||
1804 (!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')))){
1dd353b5 1805 /*
1806 * These versions have the SSH2 RSA padding bug.
1807 */
51470298 1808 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1dd353b5 1809 logevent("We believe remote version has SSH2 RSA padding bug");
1810 }
8e975795 1811
1812 if (cfg.sshbug_dhgex2 == BUG_ON) {
1813 /*
1814 * These versions have the SSH2 DH GEX bug.
1815 */
51470298 1816 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
8e975795 1817 logevent("We believe remote version has SSH2 DH group exchange bug");
1818 }
7d503c31 1819}
1820
51470298 1821static int do_ssh_init(Ssh ssh, unsigned char c)
32874aea 1822{
51470298 1823 struct do_ssh_init_state {
1824 int vslen;
1825 char version[10];
1826 char *vstring;
1827 int vstrsize;
1828 int i;
1829 int proto1, proto2;
1830 };
1831 crState(do_ssh_init_state);
374330e2 1832
51470298 1833 crBegin(ssh->do_ssh_init_crstate);
8df7a775 1834
1835 /* Search for the string "SSH-" in the input. */
51470298 1836 s->i = 0;
8df7a775 1837 while (1) {
1838 static const int transS[] = { 1, 2, 2, 1 };
1839 static const int transH[] = { 0, 0, 3, 0 };
1840 static const int transminus[] = { 0, 0, 0, -1 };
32874aea 1841 if (c == 'S')
51470298 1842 s->i = transS[s->i];
32874aea 1843 else if (c == 'H')
51470298 1844 s->i = transH[s->i];
32874aea 1845 else if (c == '-')
51470298 1846 s->i = transminus[s->i];
32874aea 1847 else
51470298 1848 s->i = 0;
1849 if (s->i < 0)
8df7a775 1850 break;
1851 crReturn(1); /* get another character */
374330e2 1852 }
8df7a775 1853
51470298 1854 s->vstrsize = 16;
1855 s->vstring = smalloc(s->vstrsize);
1856 strcpy(s->vstring, "SSH-");
1857 s->vslen = 4;
1858 s->i = 0;
374330e2 1859 while (1) {
8df7a775 1860 crReturn(1); /* get another char */
51470298 1861 if (s->vslen >= s->vstrsize - 1) {
1862 s->vstrsize += 16;
1863 s->vstring = srealloc(s->vstring, s->vstrsize);
32874aea 1864 }
51470298 1865 s->vstring[s->vslen++] = c;
1866 if (s->i >= 0) {
374330e2 1867 if (c == '-') {
51470298 1868 s->version[s->i] = '\0';
1869 s->i = -1;
1870 } else if (s->i < sizeof(s->version) - 1)
1871 s->version[s->i++] = c;
32874aea 1872 } else if (c == '\n')
374330e2 1873 break;
1874 }
1875
51470298 1876 ssh->agentfwd_enabled = FALSE;
1877 ssh->rdpkt2_state.incoming_sequence = 0;
960e736a 1878
51470298 1879 s->vstring[s->vslen] = 0;
1880 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1881 {
1882 char *vlog;
1883 vlog = smalloc(20 + s->vslen);
1884 sprintf(vlog, "Server version: %s", s->vstring);
1885 logevent(vlog);
1886 sfree(vlog);
1887 }
1888 ssh_detect_bugs(ssh, s->vstring);
c5e9c988 1889
adf799dd 1890 /*
38d228a2 1891 * Decide which SSH protocol version to support.
adf799dd 1892 */
38d228a2 1893
1894 /* Anything strictly below "2.0" means protocol 1 is supported. */
51470298 1895 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
38d228a2 1896 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
51470298 1897 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
38d228a2 1898
51470298 1899 if (cfg.sshprot == 0 && !s->proto1) {
a8327734 1900 bombout((ssh,"SSH protocol version 1 required by user but not provided by server"));
38d228a2 1901 crReturn(0);
1902 }
51470298 1903 if (cfg.sshprot == 3 && !s->proto2) {
a8327734 1904 bombout((ssh,"SSH protocol version 2 required by user but not provided by server"));
38d228a2 1905 crReturn(0);
1906 }
1907
51470298 1908 if (s->proto2 && (cfg.sshprot >= 2 || !s->proto1)) {
32874aea 1909 /*
38d228a2 1910 * Use v2 protocol.
32874aea 1911 */
1912 char verstring[80], vlog[100];
1913 sprintf(verstring, "SSH-2.0-%s", sshver);
51470298 1914 SHA_Init(&ssh->exhashbase);
32874aea 1915 /*
1916 * Hash our version string and their version string.
1917 */
51470298 1918 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1919 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
32874aea 1920 sprintf(vlog, "We claim version: %s", verstring);
1921 logevent(vlog);
1922 strcat(verstring, "\n");
1923 logevent("Using SSH protocol version 2");
51470298 1924 sk_write(ssh->s, verstring, strlen(verstring));
1925 ssh->protocol = ssh2_protocol;
1926 ssh->version = 2;
1927 ssh->s_rdpkt = ssh2_rdpkt;
e5574168 1928 } else {
32874aea 1929 /*
38d228a2 1930 * Use v1 protocol.
32874aea 1931 */
1932 char verstring[80], vlog[100];
1933 sprintf(verstring, "SSH-%s-%s",
51470298 1934 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
32874aea 1935 sshver);
1936 sprintf(vlog, "We claim version: %s", verstring);
1937 logevent(vlog);
1938 strcat(verstring, "\n");
759712a6 1939
32874aea 1940 logevent("Using SSH protocol version 1");
51470298 1941 sk_write(ssh->s, verstring, strlen(verstring));
1942 ssh->protocol = ssh1_protocol;
1943 ssh->version = 1;
1944 ssh->s_rdpkt = ssh1_rdpkt;
e5574168 1945 }
51470298 1946 ssh->state = SSH_STATE_BEFORE_SIZE;
8df7a775 1947
51470298 1948 sfree(s->vstring);
50526e47 1949
8df7a775 1950 crFinish(0);
1951}
1952
51470298 1953static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
8df7a775 1954{
51470298 1955 crBegin(ssh->ssh_gotdata_crstate);
8df7a775 1956
1957 /*
1958 * To begin with, feed the characters one by one to the
1959 * protocol initialisation / selection function do_ssh_init().
1960 * When that returns 0, we're done with the initial greeting
1961 * exchange and can move on to packet discipline.
1962 */
1963 while (1) {
51470298 1964 int ret; /* need not be kept across crReturn */
8df7a775 1965 if (datalen == 0)
1966 crReturnV; /* more data please */
51470298 1967 ret = do_ssh_init(ssh, *data);
32874aea 1968 data++;
1969 datalen--;
8df7a775 1970 if (ret == 0)
1971 break;
1972 }
1973
1974 /*
1975 * We emerge from that loop when the initial negotiation is
1976 * over and we have selected an s_rdpkt function. Now pass
1977 * everything to s_rdpkt, and then pass the resulting packets
1978 * to the proper protocol handler.
1979 */
1980 if (datalen == 0)
1981 crReturnV;
1982 while (1) {
1983 while (datalen > 0) {
51470298 1984 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
1985 if (ssh->state == SSH_STATE_CLOSED) {
e14d0f19 1986 return;
1987 }
51470298 1988 ssh->protocol(ssh, NULL, 0, 1);
1989 if (ssh->state == SSH_STATE_CLOSED) {
8df7a775 1990 return;
1991 }
1992 }
1993 }
1994 crReturnV;
1995 }
1996 crFinishV;
1997}
1998
32874aea 1999static int ssh_closing(Plug plug, char *error_msg, int error_code,
2000 int calling_back)
2001{
51470298 2002 Ssh ssh = (Ssh) plug;
2003 ssh->state = SSH_STATE_CLOSED;
2004 if (ssh->s) {
2005 sk_close(ssh->s);
2006 ssh->s = NULL;
f3ab576e 2007 }
7e78000d 2008 if (error_msg) {
32874aea 2009 /* A socket error has occurred. */
247308b5 2010 logevent(error_msg);
a8327734 2011 connection_fatal(ssh->frontend, error_msg);
7e78000d 2012 } else {
2013 /* Otherwise, the remote side closed the connection normally. */
8df7a775 2014 }
7e78000d 2015 return 0;
2016}
2017
32874aea 2018static int ssh_receive(Plug plug, int urgent, char *data, int len)
2019{
51470298 2020 Ssh ssh = (Ssh) plug;
2021 ssh_gotdata(ssh, data, len);
2022 if (ssh->state == SSH_STATE_CLOSED) {
2023 if (ssh->s) {
2024 sk_close(ssh->s);
2025 ssh->s = NULL;
32874aea 2026 }
2027 return 0;
3257deae 2028 }
fef97f43 2029 return 1;
374330e2 2030}
2031
5471d09a 2032static void ssh_sent(Plug plug, int bufsize)
2033{
51470298 2034 Ssh ssh = (Ssh) plug;
5471d09a 2035 /*
2036 * If the send backlog on the SSH socket itself clears, we
2037 * should unthrottle the whole world if it was throttled.
2038 */
2039 if (bufsize < SSH_MAX_BACKLOG)
51470298 2040 ssh_throttle_all(ssh, 0, bufsize);
5471d09a 2041}
2042
fb09bf1c 2043/*
8df7a775 2044 * Connect to specified host and port.
2045 * Returns an error message, or NULL on success.
6e1ebb76 2046 * Also places the canonical host name into `realhost'. It must be
2047 * freed by the caller.
8df7a775 2048 */
51470298 2049static char *connect_to_host(Ssh ssh, char *host, int port,
2050 char **realhost, int nodelay)
8df7a775 2051{
51470298 2052 static const struct plug_function_table fn_table = {
7e78000d 2053 ssh_closing,
5471d09a 2054 ssh_receive,
2055 ssh_sent,
2056 NULL
51470298 2057 };
7e78000d 2058
8df7a775 2059 SockAddr addr;
2060 char *err;
8df7a775 2061
51470298 2062 ssh->savedhost = smalloc(1 + strlen(host));
2063 if (!ssh->savedhost)
8df7a775 2064 fatalbox("Out of memory");
51470298 2065 strcpy(ssh->savedhost, host);
8df7a775 2066
2067 if (port < 0)
2068 port = 22; /* default ssh port */
51470298 2069 ssh->savedport = port;
8df7a775 2070
2071 /*
2072 * Try to find host.
2073 */
57356d63 2074 logeventf(ssh, "Looking up host \"%s\"", host);
8df7a775 2075 addr = sk_namelookup(host, realhost);
32874aea 2076 if ((err = sk_addr_error(addr)))
8df7a775 2077 return err;
2078
8df7a775 2079 /*
2080 * Open socket.
2081 */
3ad9d396 2082 {
57356d63 2083 char addrbuf[100];
3ad9d396 2084 sk_getaddr(addr, addrbuf, 100);
57356d63 2085 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
3ad9d396 2086 }
51470298 2087 ssh->fn = &fn_table;
2088 ssh->s = new_connection(addr, *realhost, port, 0, 1, nodelay, (Plug) ssh);
2089 if ((err = sk_socket_error(ssh->s))) {
2090 ssh->s = NULL;
8df7a775 2091 return err;
67c4ba2e 2092 }
8df7a775 2093
8df7a775 2094 return NULL;
2095}
2096
2097/*
5471d09a 2098 * Throttle or unthrottle the SSH connection.
2099 */
51470298 2100static void ssh1_throttle(Ssh ssh, int adjust)
5471d09a 2101{
51470298 2102 int old_count = ssh->v1_throttle_count;
2103 ssh->v1_throttle_count += adjust;
2104 assert(ssh->v1_throttle_count >= 0);
2105 if (ssh->v1_throttle_count && !old_count) {
2106 sk_set_frozen(ssh->s, 1);
2107 } else if (!ssh->v1_throttle_count && old_count) {
2108 sk_set_frozen(ssh->s, 0);
5471d09a 2109 }
2110}
2111
2112/*
2113 * Throttle or unthrottle _all_ local data streams (for when sends
2114 * on the SSH connection itself back up).
2115 */
51470298 2116static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
5471d09a 2117{
2118 int i;
2119 struct ssh_channel *c;
2120
51470298 2121 if (enable == ssh->throttled_all)
5471d09a 2122 return;
51470298 2123 ssh->throttled_all = enable;
2124 ssh->overall_bufsize = bufsize;
2125 if (!ssh->channels)
5471d09a 2126 return;
51470298 2127 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5471d09a 2128 switch (c->type) {
2129 case CHAN_MAINSESSION:
2130 /*
2131 * This is treated separately, outside the switch.
2132 */
2133 break;
2134 case CHAN_X11:
2135 x11_override_throttle(c->u.x11.s, enable);
2136 break;
2137 case CHAN_AGENT:
2138 /* Agent channels require no buffer management. */
2139 break;
2140 case CHAN_SOCKDATA:
2141 pfd_override_throttle(c->u.x11.s, enable);
2142 break;
2143 }
2144 }
2145}
2146
2147/*
51470298 2148 * Username and password input, abstracted off into routines
2149 * reusable in several places - even between SSH1 and SSH2.
0405e71f 2150 */
0405e71f 2151
2152/* Set up a username or password input loop on a given buffer. */
51470298 2153void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
0405e71f 2154{
51470298 2155 ssh->userpass_input_buffer = buffer;
2156 ssh->userpass_input_buflen = buflen;
2157 ssh->userpass_input_bufpos = 0;
2158 ssh->userpass_input_echo = echo;
0405e71f 2159}
2160
2161/*
2162 * Process some terminal data in the course of username/password
2163 * input. Returns >0 for success (line of input returned in
2164 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2165 * for inconclusive (keep waiting for more input please).
2166 */
51470298 2167int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
0405e71f 2168{
2169 char c;
2170
2171 while (inlen--) {
2172 switch (c = *in++) {
2173 case 10:
2174 case 13:
51470298 2175 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2176 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
0405e71f 2177 return +1;
2178 break;
2179 case 8:
2180 case 127:
51470298 2181 if (ssh->userpass_input_bufpos > 0) {
2182 if (ssh->userpass_input_echo)
2183 c_write_str(ssh, "\b \b");
2184 ssh->userpass_input_bufpos--;
0405e71f 2185 }
2186 break;
2187 case 21:
2188 case 27:
51470298 2189 while (ssh->userpass_input_bufpos > 0) {
2190 if (ssh->userpass_input_echo)
2191 c_write_str(ssh, "\b \b");
2192 ssh->userpass_input_bufpos--;
0405e71f 2193 }
2194 break;
2195 case 3:
2196 case 4:
2197 return -1;
2198 break;
2199 default:
2200 if (((c >= ' ' && c <= '~') ||
2201 ((unsigned char) c >= 160))
51470298 2202 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2203 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2204 if (ssh->userpass_input_echo)
2205 c_write(ssh, &c, 1);
0405e71f 2206 }
2207 break;
2208 }
2209 }
2210 return 0;
2211}
2212
2213/*
fb09bf1c 2214 * Handle the key exchange and user authentication phases.
2215 */
51470298 2216static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
fb09bf1c 2217{
2d466ffd 2218 int i, j;
374330e2 2219 unsigned char cookie[8];
2220 struct RSAKey servkey, hostkey;
2221 struct MD5Context md5c;
51470298 2222 struct do_ssh1_login_state {
2223 int len;
2224 unsigned char *rsabuf, *keystr1, *keystr2;
2225 unsigned long supported_ciphers_mask, supported_auths_mask;
2226 int tried_publickey, tried_agent;
2227 int tis_auth_refused, ccard_auth_refused;
2228 unsigned char session_id[16];
2229 int cipher_type;
2230 char username[100];
2231 void *publickey_blob;
2232 int publickey_bloblen;
2233 char password[100];
2234 char prompt[200];
2235 int pos;
2236 char c;
2237 int pwpkt_type;
2238 unsigned char request[5], *response, *p;
2239 int responselen;
2240 int keyi, nkeys;
2241 int authed;
2242 struct RSAKey key;
2243 Bignum challenge;
2244 char *commentp;
2245 int commentlen;
2246 };
2247 crState(do_ssh1_login_state);
2248
2249 crBegin(ssh->do_ssh1_login_crstate);
374330e2 2250
32874aea 2251 if (!ispkt)
2252 crWaitUntil(ispkt);
374330e2 2253
51470298 2254 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
a8327734 2255 bombout((ssh,"Public key packet not received"));
32874aea 2256 crReturn(0);
8d5de777 2257 }
374330e2 2258
c5e9c988 2259 logevent("Received public keys");
374330e2 2260
51470298 2261 memcpy(cookie, ssh->pktin.body, 8);
374330e2 2262
51470298 2263 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2264 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
374330e2 2265
c5e9c988 2266 /*
1c2a93c4 2267 * Log the host key fingerprint.
c5e9c988 2268 */
c5e9c988 2269 {
2270 char logmsg[80];
1c2a93c4 2271 logevent("Host key fingerprint is:");
c5e9c988 2272 strcpy(logmsg, " ");
32874aea 2273 hostkey.comment = NULL;
2274 rsa_fingerprint(logmsg + strlen(logmsg),
2275 sizeof(logmsg) - strlen(logmsg), &hostkey);
c5e9c988 2276 logevent(logmsg);
2277 }
2278
51470298 2279 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2280 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2281 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
bea1ef5f 2282
51470298 2283 ssh->v1_local_protoflags =
2284 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2285 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
b96dc54c 2286
c5e9c988 2287 MD5Init(&md5c);
51470298 2288 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2289 MD5Update(&md5c, s->keystr1, servkey.bytes);
2290 MD5Update(&md5c, ssh->pktin.body, 8);
2291 MD5Final(s->session_id, &md5c);
374330e2 2292
32874aea 2293 for (i = 0; i < 32; i++)
51470298 2294 ssh->session_key[i] = random_byte();
374330e2 2295
51470298 2296 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
374330e2 2297
51470298 2298 s->rsabuf = smalloc(s->len);
2299 if (!s->rsabuf)
374330e2 2300 fatalbox("Out of memory");
2301
89ee5268 2302 /*
2303 * Verify the host key.
2304 */
2305 {
32874aea 2306 /*
2307 * First format the key into a string.
2308 */
2309 int len = rsastr_len(&hostkey);
2310 char fingerprint[100];
2311 char *keystr = smalloc(len);
2312 if (!keystr)
2313 fatalbox("Out of memory");
2314 rsastr_fmt(keystr, &hostkey);
2315 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
a8327734 2316 verify_ssh_host_key(ssh->frontend,
2317 ssh->savedhost, ssh->savedport, "rsa", keystr,
32874aea 2318 fingerprint);
2319 sfree(keystr);
2320 }
2321
2322 for (i = 0; i < 32; i++) {
51470298 2323 s->rsabuf[i] = ssh->session_key[i];
374330e2 2324 if (i < 16)
51470298 2325 s->rsabuf[i] ^= s->session_id[i];
374330e2 2326 }
2327
2328 if (hostkey.bytes > servkey.bytes) {
51470298 2329 rsaencrypt(s->rsabuf, 32, &servkey);
2330 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
374330e2 2331 } else {
51470298 2332 rsaencrypt(s->rsabuf, 32, &hostkey);
2333 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
374330e2 2334 }
2335
c5e9c988 2336 logevent("Encrypted session key");
2337
ca20bfcf 2338 {
2339 int cipher_chosen = 0, warn = 0;
2340 char *cipher_string = NULL;
51470298 2341 int i;
ca20bfcf 2342 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2343 int next_cipher = cfg.ssh_cipherlist[i];
2344 if (next_cipher == CIPHER_WARN) {
2345 /* If/when we choose a cipher, warn about it */
2346 warn = 1;
2347 } else if (next_cipher == CIPHER_AES) {
2348 /* XXX Probably don't need to mention this. */
2349 logevent("AES not supported in SSH1, skipping");
2350 } else {
2351 switch (next_cipher) {
51470298 2352 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
ca20bfcf 2353 cipher_string = "3DES"; break;
51470298 2354 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
ca20bfcf 2355 cipher_string = "Blowfish"; break;
51470298 2356 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
ca20bfcf 2357 cipher_string = "single-DES"; break;
2358 }
51470298 2359 if (s->supported_ciphers_mask & (1 << s->cipher_type))
ca20bfcf 2360 cipher_chosen = 1;
2361 }
2362 }
2363 if (!cipher_chosen) {
51470298 2364 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
a8327734 2365 bombout((ssh,"Server violates SSH 1 protocol by not "
ca20bfcf 2366 "supporting 3DES encryption"));
2367 else
2368 /* shouldn't happen */
a8327734 2369 bombout((ssh,"No supported ciphers found"));
a99a05c0 2370 crReturn(0);
2371 }
ca20bfcf 2372
2373 /* Warn about chosen cipher if necessary. */
2374 if (warn)
a8327734 2375 askcipher(ssh->frontend, cipher_string, 0);
bea1ef5f 2376 }
ca20bfcf 2377
51470298 2378 switch (s->cipher_type) {
32874aea 2379 case SSH_CIPHER_3DES:
2380 logevent("Using 3DES encryption");
2381 break;
2382 case SSH_CIPHER_DES:
2383 logevent("Using single-DES encryption");
2384 break;
2385 case SSH_CIPHER_BLOWFISH:
2386 logevent("Using Blowfish encryption");
2387 break;
c5e9c988 2388 }
bea1ef5f 2389
51470298 2390 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2391 PKT_CHAR, s->cipher_type,
32874aea 2392 PKT_DATA, cookie, 8,
51470298 2393 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2394 PKT_DATA, s->rsabuf, s->len,
2395 PKT_INT, ssh->v1_local_protoflags, PKT_END);
fb09bf1c 2396
c5e9c988 2397 logevent("Trying to enable encryption...");
374330e2 2398
51470298 2399 sfree(s->rsabuf);
374330e2 2400
51470298 2401 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2402 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2403 &ssh_3des);
371e569c 2404 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2405 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
57356d63 2406 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
374330e2 2407
0183b242 2408 ssh->crcda_ctx = crcda_make_context();
2409 logevent("Installing CRC compensation attack detector");
2410
fb09bf1c 2411 crWaitUntil(ispkt);
374330e2 2412
51470298 2413 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
a8327734 2414 bombout((ssh,"Encryption not successfully enabled"));
32874aea 2415 crReturn(0);
8d5de777 2416 }
374330e2 2417
c5e9c988 2418 logevent("Successfully started encryption");
2419
374330e2 2420 fflush(stdout);
2421 {
67779be7 2422 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
c0a81592 2423 if (ssh_get_line && !ssh_getline_pw_only) {
32874aea 2424 if (!ssh_get_line("login as: ",
51470298 2425 s->username, sizeof(s->username), FALSE)) {
32874aea 2426 /*
2427 * get_line failed to get a username.
2428 * Terminate.
2429 */
2430 logevent("No username provided. Abandoning session.");
51470298 2431 ssh->state = SSH_STATE_CLOSED;
32874aea 2432 crReturn(1);
2433 }
2434 } else {
51470298 2435 int ret; /* need not be kept over crReturn */
2436 c_write_str(ssh, "login as: ");
2437 ssh->send_ok = 1;
0405e71f 2438
51470298 2439 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
0405e71f 2440 do {
32874aea 2441 crWaitUntil(!ispkt);
51470298 2442 ret = process_userpass_input(ssh, in, inlen);
0405e71f 2443 } while (ret == 0);
2444 if (ret < 0)
2445 cleanup_exit(0);
51470298 2446 c_write_str(ssh, "\r\n");
32874aea 2447 }
2448 } else {
51470298 2449 strncpy(s->username, cfg.username, sizeof(s->username));
2450 s->username[sizeof(s->username)-1] = '\0';
374330e2 2451 }
fb09bf1c 2452
51470298 2453 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
c5e9c988 2454 {
51470298 2455 char userlog[22 + sizeof(s->username)];
2456 sprintf(userlog, "Sent username \"%s\"", s->username);
c5e9c988 2457 logevent(userlog);
32874aea 2458 if (flags & FLAG_INTERACTIVE &&
2459 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
3c8e959b 2460 strcat(userlog, "\r\n");
51470298 2461 c_write_str(ssh, userlog);
3c8e959b 2462 }
c5e9c988 2463 }
374330e2 2464 }
2465
fb09bf1c 2466 crWaitUntil(ispkt);
374330e2 2467
51470298 2468 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
0df73905 2469 /* We must not attempt PK auth. Pretend we've already tried it. */
51470298 2470 s->tried_publickey = s->tried_agent = 1;
0df73905 2471 } else {
51470298 2472 s->tried_publickey = s->tried_agent = 0;
0df73905 2473 }
51470298 2474 s->tis_auth_refused = s->ccard_auth_refused = 0;
396778f1 2475 /* Load the public half of cfg.keyfile so we notice if it's in Pageant */
2476 if (*cfg.keyfile) {
51470298 2477 if (!rsakey_pubblob(cfg.keyfile,
2478 &s->publickey_blob, &s->publickey_bloblen))
2479 s->publickey_blob = NULL;
396778f1 2480 } else
51470298 2481 s->publickey_blob = NULL;
7cca0d81 2482
51470298 2483 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2484 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
614a20a0 2485
51470298 2486 if (agent_exists() && !s->tried_agent) {
32874aea 2487 /*
2488 * Attempt RSA authentication using Pageant.
2489 */
32874aea 2490 void *r;
2491
51470298 2492 s->authed = FALSE;
2493 s->tried_agent = 1;
32874aea 2494 logevent("Pageant is running. Requesting keys.");
2495
2496 /* Request the keys held by the agent. */
51470298 2497 PUT_32BIT(s->request, 1);
2498 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2499 agent_query(s->request, 5, &r, &s->responselen);
2500 s->response = (unsigned char *) r;
2501 if (s->response && s->responselen >= 5 &&
2502 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2503 s->p = s->response + 5;
2504 s->nkeys = GET_32BIT(s->p);
2505 s->p += 4;
32874aea 2506 {
2507 char buf[64];
51470298 2508 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
32874aea 2509 logevent(buf);
2510 }
51470298 2511 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
32874aea 2512 {
2513 char buf[64];
51470298 2514 sprintf(buf, "Trying Pageant key #%d", s->keyi);
32874aea 2515 logevent(buf);
2516 }
51470298 2517 if (s->publickey_blob &&
2518 !memcmp(s->p, s->publickey_blob,
2519 s->publickey_bloblen)) {
396778f1 2520 logevent("This key matches configured key file");
51470298 2521 s->tried_publickey = 1;
396778f1 2522 }
51470298 2523 s->p += 4;
2524 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2525 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2526 s->commentlen = GET_32BIT(s->p);
2527 s->p += 4;
2528 s->commentp = s->p;
2529 s->p += s->commentlen;
2530 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2531 PKT_BIGNUM, s->key.modulus, PKT_END);
32874aea 2532 crWaitUntil(ispkt);
51470298 2533 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
32874aea 2534 logevent("Key refused");
2535 continue;
2536 }
2537 logevent("Received RSA challenge");
51470298 2538 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
32874aea 2539 {
2540 char *agentreq, *q, *ret;
2d466ffd 2541 void *vret;
32874aea 2542 int len, retlen;
2543 len = 1 + 4; /* message type, bit count */
51470298 2544 len += ssh1_bignum_length(s->key.exponent);
2545 len += ssh1_bignum_length(s->key.modulus);
2546 len += ssh1_bignum_length(s->challenge);
32874aea 2547 len += 16; /* session id */
2548 len += 4; /* response format */
2549 agentreq = smalloc(4 + len);
2550 PUT_32BIT(agentreq, len);
2551 q = agentreq + 4;
2552 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
51470298 2553 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
32874aea 2554 q += 4;
51470298 2555 q += ssh1_write_bignum(q, s->key.exponent);
2556 q += ssh1_write_bignum(q, s->key.modulus);
2557 q += ssh1_write_bignum(q, s->challenge);
2558 memcpy(q, s->session_id, 16);
32874aea 2559 q += 16;
2560 PUT_32BIT(q, 1); /* response format */
2d466ffd 2561 agent_query(agentreq, len + 4, &vret, &retlen);
2562 ret = vret;
32874aea 2563 sfree(agentreq);
2564 if (ret) {
2565 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2566 logevent("Sending Pageant's response");
51470298 2567 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
32874aea 2568 PKT_DATA, ret + 5, 16,
2569 PKT_END);
2570 sfree(ret);
2571 crWaitUntil(ispkt);
51470298 2572 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
32874aea 2573 logevent
2574 ("Pageant's response accepted");
2575 if (flags & FLAG_VERBOSE) {
51470298 2576 c_write_str(ssh, "Authenticated using"
2577 " RSA key \"");
2578 c_write(ssh, s->commentp,
2579 s->commentlen);
2580 c_write_str(ssh, "\" from agent\r\n");
32874aea 2581 }
51470298 2582 s->authed = TRUE;
32874aea 2583 } else
2584 logevent
2585 ("Pageant's response not accepted");
2586 } else {
2587 logevent
2588 ("Pageant failed to answer challenge");
2589 sfree(ret);
2590 }
2591 } else {
2592 logevent("No reply received from Pageant");
2593 }
2594 }
51470298 2595 freebn(s->key.exponent);
2596 freebn(s->key.modulus);
2597 freebn(s->challenge);
2598 if (s->authed)
32874aea 2599 break;
2600 }
2601 }
51470298 2602 if (s->authed)
32874aea 2603 break;
2604 }
51470298 2605 if (*cfg.keyfile && !s->tried_publickey)
2606 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
32874aea 2607
614a20a0 2608 if (cfg.try_tis_auth &&
51470298 2609 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2610 !s->tis_auth_refused) {
2611 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
32874aea 2612 logevent("Requested TIS authentication");
51470298 2613 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
32874aea 2614 crWaitUntil(ispkt);
51470298 2615 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
32874aea 2616 logevent("TIS authentication declined");
2617 if (flags & FLAG_INTERACTIVE)
51470298 2618 c_write_str(ssh, "TIS authentication refused.\r\n");
2619 s->tis_auth_refused = 1;
614a20a0 2620 continue;
32874aea 2621 } else {
51470298 2622 int challengelen = GET_32BIT(ssh->pktin.body);
32874aea 2623 logevent("Received TIS challenge");
51470298 2624 if (challengelen > sizeof(s->prompt) - 1)
2625 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2626 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
614a20a0 2627 /* Prompt heuristic comes from OpenSSH */
51470298 2628 strncpy(s->prompt + challengelen,
2629 memchr(s->prompt, '\n', challengelen) ?
614a20a0 2630 "": "\r\nResponse: ",
51470298 2631 (sizeof s->prompt) - challengelen);
2632 s->prompt[(sizeof s->prompt) - 1] = '\0';
32874aea 2633 }
2634 }
614a20a0 2635 if (cfg.try_tis_auth &&
51470298 2636 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2637 !s->ccard_auth_refused) {
2638 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
32874aea 2639 logevent("Requested CryptoCard authentication");
51470298 2640 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
32874aea 2641 crWaitUntil(ispkt);
51470298 2642 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
32874aea 2643 logevent("CryptoCard authentication declined");
51470298 2644 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2645 s->ccard_auth_refused = 1;
614a20a0 2646 continue;
32874aea 2647 } else {
51470298 2648 int challengelen = GET_32BIT(ssh->pktin.body);
32874aea 2649 logevent("Received CryptoCard challenge");
51470298 2650 if (challengelen > sizeof(s->prompt) - 1)
2651 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2652 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2653 strncpy(s->prompt + challengelen,
2654 memchr(s->prompt, '\n', challengelen) ?
614a20a0 2655 "" : "\r\nResponse: ",
51470298 2656 sizeof(s->prompt) - challengelen);
2657 s->prompt[sizeof(s->prompt) - 1] = '\0';
32874aea 2658 }
2659 }
51470298 2660 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2661 sprintf(s->prompt, "%.90s@%.90s's password: ",
2662 s->username, ssh->savedhost);
32874aea 2663 }
51470298 2664 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
32874aea 2665 char *comment = NULL;
231ee168 2666 int type;
2667 char msgbuf[256];
32874aea 2668 if (flags & FLAG_VERBOSE)
51470298 2669 c_write_str(ssh, "Trying public key authentication.\r\n");
57356d63 2670 logeventf(ssh, "Trying public key \"%s\"", cfg.keyfile);
231ee168 2671 type = key_type(cfg.keyfile);
2672 if (type != SSH_KEYTYPE_SSH1) {
2673 sprintf(msgbuf, "Key is of wrong type (%s)",
2674 key_type_to_str(type));
2675 logevent(msgbuf);
51470298 2676 c_write_str(ssh, msgbuf);
2677 c_write_str(ssh, "\r\n");
2678 s->tried_publickey = 1;
231ee168 2679 continue;
2680 }
32874aea 2681 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
2682 if (flags & FLAG_VERBOSE)
51470298 2683 c_write_str(ssh, "No passphrase required.\r\n");
32874aea 2684 goto tryauth;
2685 }
51470298 2686 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
32874aea 2687 sfree(comment);
2688 }
a52f067e 2689
614a20a0 2690 /*
2691 * Show password prompt, having first obtained it via a TIS
2692 * or CryptoCard exchange if we're doing TIS or CryptoCard
2693 * authentication.
2694 */
fa17a66e 2695 if (ssh_get_line) {
51470298 2696 if (!ssh_get_line(s->prompt, s->password,
2697 sizeof(s->password), TRUE)) {
32874aea 2698 /*
2699 * get_line failed to get a password (for example
2700 * because one was supplied on the command line
2701 * which has already failed to work). Terminate.
2702 */
51470298 2703 send_packet(ssh, SSH1_MSG_DISCONNECT,
2bc6a386 2704 PKT_STR, "No more passwords available to try",
2705 PKT_END);
247308b5 2706 logevent("Unable to authenticate");
a8327734 2707 connection_fatal(ssh->frontend, "Unable to authenticate");
51470298 2708 ssh->state = SSH_STATE_CLOSED;
32874aea 2709 crReturn(1);
2710 }
fb09bf1c 2711 } else {
614a20a0 2712 /* Prompt may have come from server. We've munged it a bit, so
2713 * we know it to be zero-terminated at least once. */
51470298 2714 int ret; /* need not be saved over crReturn */
2715 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2716 s->pos = 0;
0405e71f 2717
51470298 2718 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
0405e71f 2719 do {
32874aea 2720 crWaitUntil(!ispkt);
51470298 2721 ret = process_userpass_input(ssh, in, inlen);
0405e71f 2722 } while (ret == 0);
2723 if (ret < 0)
2724 cleanup_exit(0);
51470298 2725 c_write_str(ssh, "\r\n");
32874aea 2726 }
2727
2728 tryauth:
51470298 2729 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
32874aea 2730 /*
2731 * Try public key authentication with the specified
2732 * key file.
2733 */
51470298 2734 s->tried_publickey = 1;
2735
2736 {
2737 int ret = loadrsakey(cfg.keyfile, &s->key, s->password);
2738 if (ret == 0) {
2739 c_write_str(ssh, "Couldn't load private key from ");
2740 c_write_str(ssh, cfg.keyfile);
2741 c_write_str(ssh, ".\r\n");
2742 continue; /* go and try password */
2743 }
2744 if (ret == -1) {
2745 c_write_str(ssh, "Wrong passphrase.\r\n");
2746 s->tried_publickey = 0;
2747 continue; /* try again */
2748 }
32874aea 2749 }
2750
2751 /*
2752 * Send a public key attempt.
2753 */
51470298 2754 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2755 PKT_BIGNUM, s->key.modulus, PKT_END);
32874aea 2756
2757 crWaitUntil(ispkt);
51470298 2758 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2759 c_write_str(ssh, "Server refused our public key.\r\n");
32874aea 2760 continue; /* go and try password */
2761 }
51470298 2762 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
a8327734 2763 bombout((ssh,"Bizarre response to offer of public key"));
32874aea 2764 crReturn(0);
2765 }
32874aea 2766
51470298 2767 {
2768 int i;
2769 unsigned char buffer[32];
2770 Bignum challenge, response;
2771
2772 ssh1_read_bignum(ssh->pktin.body, &challenge);
2773 response = rsadecrypt(challenge, &s->key);
2774 freebn(s->key.private_exponent);/* burn the evidence */
32874aea 2775
51470298 2776 for (i = 0; i < 32; i++) {
2777 buffer[i] = bignum_byte(response, 31 - i);
2778 }
2779
2780 MD5Init(&md5c);
2781 MD5Update(&md5c, buffer, 32);
2782 MD5Update(&md5c, s->session_id, 16);
2783 MD5Final(buffer, &md5c);
32874aea 2784
51470298 2785 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2786 PKT_DATA, buffer, 16, PKT_END);
2787
2788 freebn(challenge);
2789 freebn(response);
2790 }
32874aea 2791
2792 crWaitUntil(ispkt);
51470298 2793 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
32874aea 2794 if (flags & FLAG_VERBOSE)
51470298 2795 c_write_str(ssh, "Failed to authenticate with"
2796 " our public key.\r\n");
32874aea 2797 continue; /* go and try password */
51470298 2798 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
a8327734 2799 bombout((ssh,"Bizarre response to RSA authentication response"));
32874aea 2800 crReturn(0);
2801 }
2802
2803 break; /* we're through! */
2804 } else {
51470298 2805 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
32874aea 2806 /*
2807 * Defence against traffic analysis: we send a
2808 * whole bunch of packets containing strings of
2809 * different lengths. One of these strings is the
2810 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2811 * The others are all random data in
2812 * SSH1_MSG_IGNORE packets. This way a passive
2813 * listener can't tell which is the password, and
2814 * hence can't deduce the password length.
2815 *
2816 * Anybody with a password length greater than 16
2817 * bytes is going to have enough entropy in their
2818 * password that a listener won't find it _that_
2819 * much help to know how long it is. So what we'll
2820 * do is:
2821 *
2822 * - if password length < 16, we send 15 packets
2823 * containing string lengths 1 through 15
2824 *
2825 * - otherwise, we let N be the nearest multiple
2826 * of 8 below the password length, and send 8
2827 * packets containing string lengths N through
2828 * N+7. This won't obscure the order of
2829 * magnitude of the password length, but it will
2830 * introduce a bit of extra uncertainty.
2831 *
2832 * A few servers (the old 1.2.18 through 1.2.22)
2833 * can't deal with SSH1_MSG_IGNORE. For these
2834 * servers, we need an alternative defence. We make
2835 * use of the fact that the password is interpreted
2836 * as a C string: so we can append a NUL, then some
2837 * random data.
bd358db1 2838 *
2839 * One server (a Cisco one) can deal with neither
2840 * SSH1_MSG_IGNORE _nor_ a padded password string.
2841 * For this server we are left with no defences
2842 * against password length sniffing.
32874aea 2843 */
51470298 2844 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
b17c8428 2845 /*
2846 * The server can deal with SSH1_MSG_IGNORE, so
2847 * we can use the primary defence.
2848 */
32874aea 2849 int bottom, top, pwlen, i;
2850 char *randomstr;
2851
51470298 2852 pwlen = strlen(s->password);
32874aea 2853 if (pwlen < 16) {
2854 bottom = 0; /* zero length passwords are OK! :-) */
2855 top = 15;
2856 } else {
2857 bottom = pwlen & ~7;
2858 top = bottom + 7;
2859 }
2860
2861 assert(pwlen >= bottom && pwlen <= top);
2862
2863 randomstr = smalloc(top + 1);
2864
2865 for (i = bottom; i <= top; i++) {
2866 if (i == pwlen)
51470298 2867 defer_packet(ssh, s->pwpkt_type,
2868 PKT_STR, s->password, PKT_END);
32874aea 2869 else {
2870 for (j = 0; j < i; j++) {
2871 do {
2872 randomstr[j] = random_byte();
2873 } while (randomstr[j] == '\0');
2874 }
2875 randomstr[i] = '\0';
51470298 2876 defer_packet(ssh, SSH1_MSG_IGNORE,
32874aea 2877 PKT_STR, randomstr, PKT_END);
2878 }
2879 }
bd358db1 2880 logevent("Sending password with camouflage packets");
51470298 2881 ssh_pkt_defersend(ssh);
bd358db1 2882 }
51470298 2883 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
b17c8428 2884 /*
2885 * The server can't deal with SSH1_MSG_IGNORE
2886 * but can deal with padded passwords, so we
2887 * can use the secondary defence.
2888 */
bd358db1 2889 char string[64];
51470298 2890 char *ss;
bd358db1 2891 int len;
2892
51470298 2893 len = strlen(s->password);
bd358db1 2894 if (len < sizeof(string)) {
51470298 2895 ss = string;
2896 strcpy(string, s->password);
bd358db1 2897 len++; /* cover the zero byte */
2898 while (len < sizeof(string)) {
2899 string[len++] = (char) random_byte();
2900 }
2901 } else {
51470298 2902 ss = s->password;
bd358db1 2903 }
2904 logevent("Sending length-padded password");
51470298 2905 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2906 PKT_DATA, ss, len, PKT_END);
bd358db1 2907 } else {
2908 /*
2909 * The server has _both_
2910 * BUG_CHOKES_ON_SSH1_IGNORE and
2911 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2912 * therefore nothing we can do.
2913 */
2914 int len;
51470298 2915 len = strlen(s->password);
bd358db1 2916 logevent("Sending unpadded password");
51470298 2917 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2918 PKT_DATA, s->password, len, PKT_END);
32874aea 2919 }
2920 } else {
51470298 2921 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
32874aea 2922 }
2923 }
c5e9c988 2924 logevent("Sent password");
51470298 2925 memset(s->password, 0, strlen(s->password));
fb09bf1c 2926 crWaitUntil(ispkt);
51470298 2927 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
32874aea 2928 if (flags & FLAG_VERBOSE)
51470298 2929 c_write_str(ssh, "Access denied\r\n");
c5e9c988 2930 logevent("Authentication refused");
51470298 2931 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
a8327734 2932 bombout((ssh,"Strange packet received, type %d", ssh->pktin.type));
32874aea 2933 crReturn(0);
374330e2 2934 }
2935 }
2936
c5e9c988 2937 logevent("Authentication successful");
2938
fb09bf1c 2939 crFinish(1);
2940}
2941
32874aea 2942void sshfwd_close(struct ssh_channel *c)
2943{
51470298 2944 Ssh ssh = c->ssh;
2945
80e48603 2946 if (c && !c->closes) {
4ed34d25 2947 /*
2948 * If the channel's remoteid is -1, we have sent
2949 * CHANNEL_OPEN for this channel, but it hasn't even been
2950 * acknowledged by the server. So we must set a close flag
2951 * on it now, and then when the server acks the channel
2952 * open, we can close it then.
2953 */
36cac739 2954 if (((int)c->remoteid) != -1) {
51470298 2955 if (ssh->version == 1) {
2956 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
4ed34d25 2957 PKT_END);
2958 } else {
51470298 2959 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
2960 ssh2_pkt_adduint32(ssh, c->remoteid);
2961 ssh2_pkt_send(ssh);
4ed34d25 2962 }
32874aea 2963 }
0357890f 2964 c->closes = 1; /* sent MSG_CLOSE */
32874aea 2965 if (c->type == CHAN_X11) {
2966 c->u.x11.s = NULL;
d74d141c 2967 logevent("Forwarded X11 connection terminated");
4ed34d25 2968 } else if (c->type == CHAN_SOCKDATA ||
2969 c->type == CHAN_SOCKDATA_DORMANT) {
d74d141c 2970 c->u.pfd.s = NULL;
2971 logevent("Forwarded port closed");
32874aea 2972 }
2973 }
2974}
2975
5471d09a 2976int sshfwd_write(struct ssh_channel *c, char *buf, int len)
32874aea 2977{
51470298 2978 Ssh ssh = c->ssh;
2979
2980 if (ssh->version == 1) {
2981 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
32874aea 2982 PKT_INT, c->remoteid,
2983 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
5471d09a 2984 /*
2985 * In SSH1 we can return 0 here - implying that forwarded
2986 * connections are never individually throttled - because
2987 * the only circumstance that can cause throttling will be
2988 * the whole SSH connection backing up, in which case
2989 * _everything_ will be throttled as a whole.
2990 */
2991 return 0;
783415f8 2992 } else {
32874aea 2993 ssh2_add_channel_data(c, buf, len);
5471d09a 2994 return ssh2_try_send(c);
2995 }
2996}
2997
2998void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
2999{
51470298 3000 Ssh ssh = c->ssh;
3001
3002 if (ssh->version == 1) {
5471d09a 3003 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
3004 c->v.v1.throttling = 0;
51470298 3005 ssh1_throttle(ssh, -1);
5471d09a 3006 }
3007 } else {
3008 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
783415f8 3009 }
9c964e85 3010}
3011
51470298 3012static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
32874aea 3013{
51470298 3014 crBegin(ssh->ssh1_protocol_crstate);
fb09bf1c 3015
3016 random_init();
3017
51470298 3018 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
fb09bf1c 3019 crReturnV;
85ee8208 3020 }
51470298 3021 if (ssh->state == SSH_STATE_CLOSED)
32874aea 3022 crReturnV;
fb09bf1c 3023
979310f1 3024 if (cfg.agentfwd && agent_exists()) {
32874aea 3025 logevent("Requesting agent forwarding");
51470298 3026 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
32874aea 3027 do {
3028 crReturnV;
3029 } while (!ispkt);
51470298 3030 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3031 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
a8327734 3032 bombout((ssh,"Protocol confusion"));
32874aea 3033 crReturnV;
51470298 3034 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
32874aea 3035 logevent("Agent forwarding refused");
3036 } else {
3037 logevent("Agent forwarding enabled");
51470298 3038 ssh->agentfwd_enabled = TRUE;
db7d555c 3039 }
dacbd0e8 3040 }
3041
9c964e85 3042 if (cfg.x11_forward) {
32874aea 3043 char proto[20], data[64];
3044 logevent("Requesting X11 forwarding");
302121de 3045 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3046 data, sizeof(data));
51470298 3047 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3048 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
32874aea 3049 PKT_STR, proto, PKT_STR, data,
3050 PKT_INT, 0, PKT_END);
3051 } else {
51470298 3052 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
32874aea 3053 PKT_STR, proto, PKT_STR, data, PKT_END);
3054 }
3055 do {
3056 crReturnV;
3057 } while (!ispkt);
51470298 3058 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3059 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
a8327734 3060 bombout((ssh,"Protocol confusion"));
32874aea 3061 crReturnV;
51470298 3062 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
32874aea 3063 logevent("X11 forwarding refused");
3064 } else {
3065 logevent("X11 forwarding enabled");
51470298 3066 ssh->X11_fwd_enabled = TRUE;
9c964e85 3067 }
3068 }
3069
d74d141c 3070 {
9bf696b1 3071 char type;
d74d141c 3072 int n;
a4fc0d74 3073 int sport,dport,sserv,dserv;
d74d141c 3074 char sports[256], dports[256], host[256];
d74d141c 3075
51470298 3076 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
d74d141c 3077 /* Add port forwardings. */
51470298 3078 ssh->portfwd_strptr = cfg.portfwd;
3079 while (*ssh->portfwd_strptr) {
3080 type = *ssh->portfwd_strptr++;
d74d141c 3081 n = 0;
51470298 3082 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t')
3083 sports[n++] = *ssh->portfwd_strptr++;
d74d141c 3084 sports[n] = 0;
51470298 3085 if (*ssh->portfwd_strptr == '\t')
3086 ssh->portfwd_strptr++;
d74d141c 3087 n = 0;
51470298 3088 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':')
3089 host[n++] = *ssh->portfwd_strptr++;
d74d141c 3090 host[n] = 0;
51470298 3091 if (*ssh->portfwd_strptr == ':')
3092 ssh->portfwd_strptr++;
d74d141c 3093 n = 0;
51470298 3094 while (*ssh->portfwd_strptr)
3095 dports[n++] = *ssh->portfwd_strptr++;
d74d141c 3096 dports[n] = 0;
51470298 3097 ssh->portfwd_strptr++;
d74d141c 3098 dport = atoi(dports);
a4fc0d74 3099 dserv = 0;
3100 if (dport == 0) {
3101 dserv = 1;
68a49acb 3102 dport = net_service_lookup(dports);
3103 if (!dport) {
57356d63 3104 logeventf(ssh, "Service lookup failed for"
3105 " destination port \"%s\"", dports);
a4fc0d74 3106 }
3107 }
d74d141c 3108 sport = atoi(sports);
a4fc0d74 3109 sserv = 0;
3110 if (sport == 0) {
3111 sserv = 1;
68a49acb 3112 sport = net_service_lookup(sports);
3113 if (!sport) {
57356d63 3114 logeventf(ssh, "Service lookup failed for source"
3115 " port \"%s\"", sports);
a4fc0d74 3116 }
3117 }
d74d141c 3118 if (sport && dport) {
3119 if (type == 'L') {
6b78788a 3120 pfd_addforward(host, dport, sport, ssh);
57356d63 3121 logeventf(ssh, "Local port %.*s%.*s%d%.*s forwarding to"
3122 " %s:%.*s%.*s%d%.*s",
3123 (int)(sserv ? strlen(sports) : 0), sports,
3124 sserv, "(", sport, sserv, ")",
3125 host,
3126 (int)(dserv ? strlen(dports) : 0), dports,
3127 dserv, "(", dport, dserv, ")");
d74d141c 3128 } else {
3129 struct ssh_rportfwd *pf;
3130 pf = smalloc(sizeof(*pf));
bc240b21 3131 strcpy(pf->dhost, host);
3132 pf->dport = dport;
51470298 3133 if (add234(ssh->rportfwds, pf) != pf) {
57356d63 3134 logeventf(ssh,
3135 "Duplicate remote port forwarding to %s:%d",
3136 host, dport);
bc240b21 3137 sfree(pf);
d74d141c 3138 } else {
57356d63 3139 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3140 " forward to %s:%.*s%.*s%d%.*s",
3141 (int)(sserv ? strlen(sports) : 0), sports,
3142 sserv, "(", sport, sserv, ")",
3143 host,
3144 (int)(dserv ? strlen(dports) : 0), dports,
3145 dserv, "(", dport, dserv, ")");
51470298 3146 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
d74d141c 3147 PKT_INT, sport,
3148 PKT_STR, host,
3149 PKT_INT, dport,
3150 PKT_END);
9bf696b1 3151 do {
3152 crReturnV;
3153 } while (!ispkt);
51470298 3154 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3155 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
a8327734 3156 bombout((ssh,"Protocol confusion"));
9bf696b1 3157 crReturnV;
51470298 3158 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3159 c_write_str(ssh, "Server refused port"
3160 " forwarding\r\n");
9bf696b1 3161 }
3162 logevent("Remote port forwarding enabled");
d74d141c 3163 }
3164 }
3165 }
3166 }
3167 }
3168
fef97f43 3169 if (!cfg.nopty) {
51470298 3170 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
32874aea 3171 PKT_STR, cfg.termtype,
51470298 3172 PKT_INT, ssh->term_height,
3173 PKT_INT, ssh->term_width,
32874aea 3174 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
51470298 3175 ssh->state = SSH_STATE_INTERMED;
32874aea 3176 do {
3177 crReturnV;
3178 } while (!ispkt);
51470298 3179 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3180 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
a8327734 3181 bombout((ssh,"Protocol confusion"));
32874aea 3182 crReturnV;
51470298 3183 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3184 c_write_str(ssh, "Server refused to allocate pty\r\n");
3185 ssh->editing = ssh->echoing = 1;
32874aea 3186 }
c5e9c988 3187 logevent("Allocated pty");
0965bee0 3188 } else {
51470298 3189 ssh->editing = ssh->echoing = 1;
374330e2 3190 }
3191
4ba9b64b 3192 if (cfg.compression) {
51470298 3193 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
32874aea 3194 do {
3195 crReturnV;
3196 } while (!ispkt);
51470298 3197 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3198 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
a8327734 3199 bombout((ssh,"Protocol confusion"));
32874aea 3200 crReturnV;
51470298 3201 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3202 c_write_str(ssh, "Server refused to compress\r\n");
32874aea 3203 }
4ba9b64b 3204 logevent("Started compression");
51470298 3205 ssh->v1_compressing = TRUE;
5366aed8 3206 ssh->cs_comp_ctx = zlib_compress_init();
3207 logevent("Initialised zlib (RFC1950) compression");
3208 ssh->sc_comp_ctx = zlib_decompress_init();
3209 logevent("Initialised zlib (RFC1950) decompression");
4ba9b64b 3210 }
3211
fd5e5847 3212 /*
3213 * Start the shell or command.
3214 *
3215 * Special case: if the first-choice command is an SSH2
3216 * subsystem (hence not usable here) and the second choice
3217 * exists, we fall straight back to that.
3218 */
3219 {
3220 char *cmd = cfg.remote_cmd_ptr;
3221
3222 if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) {
3223 cmd = cfg.remote_cmd_ptr2;
51470298 3224 ssh->fallback_cmd = TRUE;
fd5e5847 3225 }
3226 if (*cmd)
51470298 3227 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
fd5e5847 3228 else
51470298 3229 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
fd5e5847 3230 logevent("Started session");
3231 }
374330e2 3232
51470298 3233 ssh->state = SSH_STATE_SESSION;
3234 if (ssh->size_needed)
3235 ssh_size(ssh, ssh->term_width, ssh->term_height);
3236 if (ssh->eof_needed)
3237 ssh_special(ssh, TS_EOF);
374330e2 3238
b9d7bcad 3239 if (ssh->ldisc)
3240 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
51470298 3241 ssh->send_ok = 1;
3242 ssh->channels = newtree234(ssh_channelcmp);
374330e2 3243 while (1) {
3244 crReturnV;
3245 if (ispkt) {
51470298 3246 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3247 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3248 long len = GET_32BIT(ssh->pktin.body);
5471d09a 3249 int bufsize =
51470298 3250 from_backend(ssh->frontend,
3251 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3252 ssh->pktin.body + 4, len);
3253 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3254 ssh->v1_stdout_throttling = 1;
3255 ssh1_throttle(ssh, +1);
5471d09a 3256 }
51470298 3257 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3258 ssh->state = SSH_STATE_CLOSED;
c5e9c988 3259 logevent("Received disconnect request");
32874aea 3260 crReturnV;
51470298 3261 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
32874aea 3262 /* Remote side is trying to open a channel to talk to our
3263 * X-Server. Give them back a local channel number. */
3264 struct ssh_channel *c;
9c964e85 3265
3266 logevent("Received X11 connect request");
3267 /* Refuse if X11 forwarding is disabled. */
51470298 3268 if (!ssh->X11_fwd_enabled) {
3269 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3270 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
9c964e85 3271 logevent("Rejected X11 connect request");
3272 } else {
9c964e85 3273 c = smalloc(sizeof(struct ssh_channel));
51470298 3274 c->ssh = ssh;
9c964e85 3275
302121de 3276 if (x11_init(&c->u.x11.s, cfg.x11_display, c,
3277 ssh->x11auth) != NULL) {
32874aea 3278 logevent("opening X11 forward connection failed");
3279 sfree(c);
51470298 3280 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3281 PKT_INT, GET_32BIT(ssh->pktin.body),
32874aea 3282 PKT_END);
9c964e85 3283 } else {
32874aea 3284 logevent
3285 ("opening X11 forward connection succeeded");
51470298 3286 c->remoteid = GET_32BIT(ssh->pktin.body);
3287 c->localid = alloc_channel_id(ssh);
32874aea 3288 c->closes = 0;
5471d09a 3289 c->v.v1.throttling = 0;
32874aea 3290 c->type = CHAN_X11; /* identify channel type */
51470298 3291 add234(ssh->channels, c);
3292 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
32874aea 3293 PKT_INT, c->remoteid, PKT_INT,
3294 c->localid, PKT_END);
3295 logevent("Opened X11 forward channel");
9c964e85 3296 }
3297 }
51470298 3298 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
32874aea 3299 /* Remote side is trying to open a channel to talk to our
3300 * agent. Give them back a local channel number. */
3301 struct ssh_channel *c;
db7d555c 3302
3303 /* Refuse if agent forwarding is disabled. */
51470298 3304 if (!ssh->agentfwd_enabled) {
3305 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3306 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
db7d555c 3307 } else {
dcbde236 3308 c = smalloc(sizeof(struct ssh_channel));
51470298 3309 c->ssh = ssh;
3310 c->remoteid = GET_32BIT(ssh->pktin.body);
3311 c->localid = alloc_channel_id(ssh);
db7d555c 3312 c->closes = 0;
5471d09a 3313 c->v.v1.throttling = 0;
32874aea 3314 c->type = CHAN_AGENT; /* identify channel type */
db7d555c 3315 c->u.a.lensofar = 0;
51470298 3316 add234(ssh->channels, c);
3317 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
db7d555c 3318 PKT_INT, c->remoteid, PKT_INT, c->localid,
3319 PKT_END);
3320 }
51470298 3321 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
d74d141c 3322 /* Remote side is trying to open a channel to talk to a
3323 * forwarded port. Give them back a local channel number. */
3324 struct ssh_channel *c;
3325 struct ssh_rportfwd pf;
3326 int hostsize, port;
3327 char host[256], buf[1024];
3328 char *p, *h, *e;
3329 c = smalloc(sizeof(struct ssh_channel));
51470298 3330 c->ssh = ssh;
d74d141c 3331
51470298 3332 hostsize = GET_32BIT(ssh->pktin.body+4);
3333 for(h = host, p = ssh->pktin.body+8; hostsize != 0; hostsize--) {
d74d141c 3334 if (h+1 < host+sizeof(host))
3335 *h++ = *p;
95bc8819 3336 p++;
d74d141c 3337 }
3338 *h = 0;
3339 port = GET_32BIT(p);
3340
bc240b21 3341 strcpy(pf.dhost, host);
3342 pf.dport = port;
d74d141c 3343
51470298 3344 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
d74d141c 3345 sprintf(buf, "Rejected remote port open request for %s:%d",
3346 host, port);
3347 logevent(buf);
51470298 3348 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3349 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
d74d141c 3350 } else {
3351 sprintf(buf, "Received remote port open request for %s:%d",
3352 host, port);
3353 logevent(buf);
3354 e = pfd_newconnect(&c->u.pfd.s, host, port, c);
3355 if (e != NULL) {
3356 char buf[256];
3357 sprintf(buf, "Port open failed: %s", e);
3358 logevent(buf);
3359 sfree(c);
51470298 3360 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3361 PKT_INT, GET_32BIT(ssh->pktin.body),
d74d141c 3362 PKT_END);
3363 } else {
51470298 3364 c->remoteid = GET_32BIT(ssh->pktin.body);
3365 c->localid = alloc_channel_id(ssh);
d74d141c 3366 c->closes = 0;
5471d09a 3367 c->v.v1.throttling = 0;
d74d141c 3368 c->type = CHAN_SOCKDATA; /* identify channel type */
51470298 3369 add234(ssh->channels, c);
3370 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
d74d141c 3371 PKT_INT, c->remoteid, PKT_INT,
3372 c->localid, PKT_END);
3373 logevent("Forwarded port opened successfully");
3374 }
3375 }
3376
51470298 3377 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3378 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3379 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
bc240b21 3380 struct ssh_channel *c;
3381
51470298 3382 c = find234(ssh->channels, &remoteid, ssh_channelfind);
bc240b21 3383 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3384 c->remoteid = localid;
3385 c->type = CHAN_SOCKDATA;
7781f316 3386 c->v.v1.throttling = 0;
bc240b21 3387 pfd_confirm(c->u.pfd.s);
3388 }
d74d141c 3389
4ed34d25 3390 if (c && c->closes) {
3391 /*
3392 * We have a pending close on this channel,
3393 * which we decided on before the server acked
3394 * the channel open. So now we know the
3395 * remoteid, we can close it again.
3396 */
51470298 3397 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3398 PKT_INT, c->remoteid, PKT_END);
4ed34d25 3399 }
3400
51470298 3401 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3402 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
724cface 3403 struct ssh_channel *c;
3404
51470298 3405 c = find234(ssh->channels, &remoteid, ssh_channelfind);
724cface 3406 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3407 logevent("Forwarded connection refused by server");
3408 pfd_close(c->u.pfd.s);
51470298 3409 del234(ssh->channels, c);
724cface 3410 sfree(c);
3411 }
3412
51470298 3413 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3414 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
32874aea 3415 /* Remote side closes a channel. */
51470298 3416 unsigned i = GET_32BIT(ssh->pktin.body);
32874aea 3417 struct ssh_channel *c;
51470298 3418 c = find234(ssh->channels, &i, ssh_channelfind);
d0d844c1 3419 if (c && ((int)c->remoteid) != -1) {
32874aea 3420 int closetype;
3421 closetype =
51470298 3422 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
0357890f 3423
783415f8 3424 if ((c->closes == 0) && (c->type == CHAN_X11)) {
d74d141c 3425 logevent("Forwarded X11 connection terminated");
9c964e85 3426 assert(c->u.x11.s != NULL);
3427 x11_close(c->u.x11.s);
3428 c->u.x11.s = NULL;
3429 }
d74d141c 3430 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3431 logevent("Forwarded port closed");
3432 assert(c->u.pfd.s != NULL);
3433 pfd_close(c->u.pfd.s);
3434 c->u.pfd.s = NULL;
3435 }
0357890f 3436
3437 c->closes |= (closetype << 2); /* seen this message */
3438 if (!(c->closes & closetype)) {
51470298 3439 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
0357890f 3440 PKT_END);
3441 c->closes |= closetype; /* sent it too */
3442 }
3443
3444 if (c->closes == 15) {
51470298 3445 del234(ssh->channels, c);
32874aea 3446 sfree(c);
3447 }
d0d844c1 3448 } else {
a8327734 3449 bombout((ssh,"Received CHANNEL_CLOSE%s for %s channel %d\n",
51470298 3450 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
d0d844c1 3451 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3452 i));
32874aea 3453 }
51470298 3454 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
32874aea 3455 /* Data sent down one of our channels. */
51470298 3456 int i = GET_32BIT(ssh->pktin.body);
3457 int len = GET_32BIT(ssh->pktin.body + 4);
3458 unsigned char *p = ssh->pktin.body + 8;
32874aea 3459 struct ssh_channel *c;
51470298 3460 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 3461 if (c) {
5471d09a 3462 int bufsize;
32874aea 3463 switch (c->type) {
3464 case CHAN_X11:
5471d09a 3465 bufsize = x11_send(c->u.x11.s, p, len);
9c964e85 3466 break;
d74d141c 3467 case CHAN_SOCKDATA:
5471d09a 3468 bufsize = pfd_send(c->u.pfd.s, p, len);
bc240b21 3469 break;
32874aea 3470 case CHAN_AGENT:
3471 /* Data for an agent message. Buffer it. */
3472 while (len > 0) {
3473 if (c->u.a.lensofar < 4) {
3474 int l = min(4 - c->u.a.lensofar, len);
3475 memcpy(c->u.a.msglen + c->u.a.lensofar, p,
3476 l);
3477 p += l;
3478 len -= l;
3479 c->u.a.lensofar += l;
3480 }
3481 if (c->u.a.lensofar == 4) {
3482 c->u.a.totallen =
3483 4 + GET_32BIT(c->u.a.msglen);
3484 c->u.a.message = smalloc(c->u.a.totallen);
3485 memcpy(c->u.a.message, c->u.a.msglen, 4);
3486 }
3487 if (c->u.a.lensofar >= 4 && len > 0) {
3488 int l =
3489 min(c->u.a.totallen - c->u.a.lensofar,
3490 len);
3491 memcpy(c->u.a.message + c->u.a.lensofar, p,
3492 l);
3493 p += l;
3494 len -= l;
3495 c->u.a.lensofar += l;
3496 }
3497 if (c->u.a.lensofar == c->u.a.totallen) {
3498 void *reply, *sentreply;
3499 int replylen;
3500 agent_query(c->u.a.message,
3501 c->u.a.totallen, &reply,
3502 &replylen);
3503 if (reply)
3504 sentreply = reply;
3505 else {
3506 /* Fake SSH_AGENT_FAILURE. */
3507 sentreply = "\0\0\0\1\5";
3508 replylen = 5;
3509 }
51470298 3510 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
32874aea 3511 PKT_INT, c->remoteid,
3512 PKT_INT, replylen,
3513 PKT_DATA, sentreply, replylen,
3514 PKT_END);
3515 if (reply)
3516 sfree(reply);
3517 sfree(c->u.a.message);
3518 c->u.a.lensofar = 0;
3519 }
3520 }
5471d09a 3521 bufsize = 0; /* agent channels never back up */
32874aea 3522 break;
3523 }
90347b95 3524 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
5471d09a 3525 c->v.v1.throttling = 1;
51470298 3526 ssh1_throttle(ssh, +1);
5471d09a 3527 }
32874aea 3528 }
51470298 3529 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
972a41c8 3530 /* may be from EXEC_SHELL on some servers */
51470298 3531 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
972a41c8 3532 /* may be from EXEC_SHELL on some servers
374330e2 3533 * if no pty is available or in other odd cases. Ignore */
51470298 3534 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
d8d6c7e5 3535 char buf[100];
51470298 3536 ssh->exitcode = GET_32BIT(ssh->pktin.body);
d8d6c7e5 3537 sprintf(buf, "Server sent command exit status %d",
51470298 3538 ssh->exitcode);
d8d6c7e5 3539 logevent(buf);
51470298 3540 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
4252c9cc 3541 /*
3542 * In case `helpful' firewalls or proxies tack
3543 * extra human-readable text on the end of the
3544 * session which we might mistake for another
3545 * encrypted packet, we close the session once
3546 * we've sent EXIT_CONFIRMATION.
3547 */
51470298 3548 ssh->state = SSH_STATE_CLOSED;
4252c9cc 3549 crReturnV;
374330e2 3550 } else {
a8327734 3551 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
32874aea 3552 crReturnV;
374330e2 3553 }
3554 } else {
8df7a775 3555 while (inlen > 0) {
3556 int len = min(inlen, 512);
51470298 3557 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
8df7a775 3558 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3559 in += len;
3560 inlen -= len;
3561 }
374330e2 3562 }
3563 }
3564
3565 crFinishV;
3566}
3567
3568/*
e5574168 3569 * Utility routine for decoding comma-separated strings in KEXINIT.
3570 */
32874aea 3571static int in_commasep_string(char *needle, char *haystack, int haylen)
3572{
57356d63 3573 int needlen;
3574 if (!needle || !haystack) /* protect against null pointers */
3575 return 0;
3576 needlen = strlen(needle);
e5574168 3577 while (1) {
32874aea 3578 /*
3579 * Is it at the start of the string?
3580 */
3581 if (haylen >= needlen && /* haystack is long enough */
3582 !memcmp(needle, haystack, needlen) && /* initial match */
3583 (haylen == needlen || haystack[needlen] == ',')
3584 /* either , or EOS follows */
3585 )
3586 return 1;
3587 /*
3588 * If not, search for the next comma and resume after that.
3589 * If no comma found, terminate.
3590 */
3591 while (haylen > 0 && *haystack != ',')
3592 haylen--, haystack++;
3593 if (haylen == 0)
3594 return 0;
3595 haylen--, haystack++; /* skip over comma itself */
e5574168 3596 }
3597}
3598
3599/*
d39f364a 3600 * SSH2 key creation method.
3601 */
51470298 3602static void ssh2_mkkey(Ssh ssh, Bignum K, char *H, char *sessid, char chr,
32874aea 3603 char *keyspace)
3604{
d39f364a 3605 SHA_State s;
3606 /* First 20 bytes. */
3607 SHA_Init(&s);
51470298 3608 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
088bde77 3609 sha_mpint(&s, K);
d39f364a 3610 SHA_Bytes(&s, H, 20);
3611 SHA_Bytes(&s, &chr, 1);
5e0d7cb8 3612 SHA_Bytes(&s, sessid, 20);
d39f364a 3613 SHA_Final(&s, keyspace);
3614 /* Next 20 bytes. */
3615 SHA_Init(&s);
51470298 3616 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
088bde77 3617 sha_mpint(&s, K);
d39f364a 3618 SHA_Bytes(&s, H, 20);
3619 SHA_Bytes(&s, keyspace, 20);
32874aea 3620 SHA_Final(&s, keyspace + 20);
d39f364a 3621}
3622
3623/*
7cca0d81 3624 * Handle the SSH2 transport layer.
e5574168 3625 */
51470298 3626static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
e5574168 3627{
51470298 3628 struct do_ssh2_transport_state {
3629 int nbits, pbits, warn;
3630 Bignum p, g, e, f, K;
3631 int kex_init_value, kex_reply_value;
3632 const struct ssh_mac **maclist;
3633 int nmacs;
3634 const struct ssh2_cipher *cscipher_tobe;
3635 const struct ssh2_cipher *sccipher_tobe;
3636 const struct ssh_mac *csmac_tobe;
3637 const struct ssh_mac *scmac_tobe;
3638 const struct ssh_compress *cscomp_tobe;
3639 const struct ssh_compress *sccomp_tobe;
3640 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3641 int hostkeylen, siglen;
3642 void *hkey; /* actual host key */
3643 unsigned char exchange_hash[20];
3644 int n_preferred_ciphers;
3645 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3646 const struct ssh_compress *preferred_comp;
3647 int first_kex;
3648 };
3649 crState(do_ssh2_transport_state);
3650
3651 crBegin(ssh->do_ssh2_transport_crstate);
3652
3653 s->cscipher_tobe = s->sccipher_tobe = NULL;
3654 s->csmac_tobe = s->scmac_tobe = NULL;
3655 s->cscomp_tobe = s->sccomp_tobe = NULL;
3656
7cca0d81 3657 random_init();
51470298 3658 s->first_kex = 1;
e5574168 3659
51470298 3660 {
3661 int i;
3662 /*
3663 * Set up the preferred ciphers. (NULL => warn below here)
3664 */
3665 s->n_preferred_ciphers = 0;
3666 for (i = 0; i < CIPHER_MAX; i++) {
3667 switch (cfg.ssh_cipherlist[i]) {
3668 case CIPHER_BLOWFISH:
3669 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3670 break;
3671 case CIPHER_DES:
3672 if (cfg.ssh2_des_cbc) {
3673 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3674 }
3675 break;
3676 case CIPHER_3DES:
3677 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3678 break;
3679 case CIPHER_AES:
3680 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3681 break;
3682 case CIPHER_WARN:
3683 /* Flag for later. Don't bother if it's the last in
3684 * the list. */
3685 if (i < CIPHER_MAX - 1) {
3686 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3687 }
3688 break;
ca20bfcf 3689 }
ca20bfcf 3690 }
5e8358ad 3691 }
ca20bfcf 3692
3693 /*
3694 * Set up preferred compression.
3695 */
4ba9b64b 3696 if (cfg.compression)
51470298 3697 s->preferred_comp = &ssh_zlib;
4ba9b64b 3698 else
51470298 3699 s->preferred_comp = &ssh_comp_none;
5e8358ad 3700
7591b9ff 3701 /*
3702 * Be prepared to work around the buggy MAC problem.
3703 */
51470298 3704 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3705 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
7591b9ff 3706 else
51470298 3707 s->maclist = macs, s->nmacs = lenof(macs);
7591b9ff 3708
32874aea 3709 begin_key_exchange:
51470298 3710 {
3711 int i, j, cipherstr_started;
3712
3713 /*
3714 * Construct and send our key exchange packet.
3715 */
3716 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3717 for (i = 0; i < 16; i++)
3718 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3719 /* List key exchange algorithms. */
3720 ssh2_pkt_addstring_start(ssh);
3721 for (i = 0; i < lenof(kex_algs); i++) {
3722 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3723 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3724 continue;
3725 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3726 if (i < lenof(kex_algs) - 1)
3727 ssh2_pkt_addstring_str(ssh, ",");
32874aea 3728 }
51470298 3729 /* List server host key algorithms. */
3730 ssh2_pkt_addstring_start(ssh);
3731 for (i = 0; i < lenof(hostkey_algs); i++) {
3732 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3733 if (i < lenof(hostkey_algs) - 1)
3734 ssh2_pkt_addstring_str(ssh, ",");
32874aea 3735 }
51470298 3736 /* List client->server encryption algorithms. */
3737 ssh2_pkt_addstring_start(ssh);
3738 cipherstr_started = 0;
3739 for (i = 0; i < s->n_preferred_ciphers; i++) {
3740 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3741 if (!c) continue; /* warning flag */
3742 for (j = 0; j < c->nciphers; j++) {
3743 if (cipherstr_started)
3744 ssh2_pkt_addstring_str(ssh, ",");
3745 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3746 cipherstr_started = 1;
3747 }
3748 }
3749 /* List server->client encryption algorithms. */
3750 ssh2_pkt_addstring_start(ssh);
3751 cipherstr_started = 0;
3752 for (i = 0; i < s->n_preferred_ciphers; i++) {
3753 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3754 if (!c) continue; /* warning flag */
3755 for (j = 0; j < c->nciphers; j++) {
3756 if (cipherstr_started)
3757 ssh2_pkt_addstring_str(ssh, ",");
3758 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3759 cipherstr_started = 1;
3760 }
3761 }
3762 /* List client->server MAC algorithms. */
3763 ssh2_pkt_addstring_start(ssh);
3764 for (i = 0; i < s->nmacs; i++) {
3765 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3766 if (i < s->nmacs - 1)
3767 ssh2_pkt_addstring_str(ssh, ",");
3768 }
3769 /* List server->client MAC algorithms. */
3770 ssh2_pkt_addstring_start(ssh);
3771 for (i = 0; i < s->nmacs; i++) {
3772 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3773 if (i < s->nmacs - 1)
3774 ssh2_pkt_addstring_str(ssh, ",");
3775 }
3776 /* List client->server compression algorithms. */
3777 ssh2_pkt_addstring_start(ssh);
3778 for (i = 0; i < lenof(compressions) + 1; i++) {
3779 const struct ssh_compress *c =
3780 i == 0 ? s->preferred_comp : compressions[i - 1];
3781 ssh2_pkt_addstring_str(ssh, c->name);
3782 if (i < lenof(compressions))
3783 ssh2_pkt_addstring_str(ssh, ",");
3784 }
3785 /* List server->client compression algorithms. */
3786 ssh2_pkt_addstring_start(ssh);
3787 for (i = 0; i < lenof(compressions) + 1; i++) {
3788 const struct ssh_compress *c =
3789 i == 0 ? s->preferred_comp : compressions[i - 1];
3790 ssh2_pkt_addstring_str(ssh, c->name);
3791 if (i < lenof(compressions))
3792 ssh2_pkt_addstring_str(ssh, ",");
3793 }
3794 /* List client->server languages. Empty list. */
3795 ssh2_pkt_addstring_start(ssh);
3796 /* List server->client languages. Empty list. */
3797 ssh2_pkt_addstring_start(ssh);
3798 /* First KEX packet does _not_ follow, because we're not that brave. */
3799 ssh2_pkt_addbool(ssh, FALSE);
3800 /* Reserved. */
3801 ssh2_pkt_adduint32(ssh, 0);
e5574168 3802 }
0db56f73 3803
51470298 3804 ssh->exhash = ssh->exhashbase;
3805 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
0db56f73 3806
51470298 3807 ssh2_pkt_send(ssh);
e5574168 3808
32874aea 3809 if (!ispkt)
3810 crWaitUntil(ispkt);
57356d63 3811 if (ssh->pktin.length > 5)
3812 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
e5574168 3813
3814 /*
3815 * Now examine the other side's KEXINIT to see what we're up
3816 * to.
3817 */
51470298 3818 {
3819 char *str;
3820 int i, j, len;
3821
3822 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
a8327734 3823 bombout((ssh,"expected key exchange packet from server"));
51470298 3824 crReturn(0);
32874aea 3825 }
51470298 3826 ssh->kex = NULL;
3827 ssh->hostkey = NULL;
3828 s->cscipher_tobe = NULL;
3829 s->sccipher_tobe = NULL;
3830 s->csmac_tobe = NULL;
3831 s->scmac_tobe = NULL;
3832 s->cscomp_tobe = NULL;
3833 s->sccomp_tobe = NULL;
3834 ssh->pktin.savedpos += 16; /* skip garbage cookie */
3835 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
3836 for (i = 0; i < lenof(kex_algs); i++) {
3837 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3838 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3839 continue;
3840 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3841 ssh->kex = kex_algs[i];
3842 break;
3843 }
32874aea 3844 }
51470298 3845 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
3846 for (i = 0; i < lenof(hostkey_algs); i++) {
3847 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3848 ssh->hostkey = hostkey_algs[i];
3849 break;
3850 }
3851 }
3852 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
3853 s->warn = 0;
3854 for (i = 0; i < s->n_preferred_ciphers; i++) {
3855 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3856 if (!c) {
3857 s->warn = 1;
3858 } else {
3859 for (j = 0; j < c->nciphers; j++) {
3860 if (in_commasep_string(c->list[j]->name, str, len)) {
3861 s->cscipher_tobe = c->list[j];
3862 break;
3863 }
ca20bfcf 3864 }
32874aea 3865 }
51470298 3866 if (s->cscipher_tobe) {
3867 if (s->warn)
a8327734 3868 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
51470298 3869 break;
3870 }
32874aea 3871 }
51470298 3872 if (!s->cscipher_tobe) {
57356d63 3873 bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)",
3874 str ? str : "(null)"));
51470298 3875 crReturn(0);
ca20bfcf 3876 }
0ef8f407 3877
51470298 3878 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
3879 s->warn = 0;
3880 for (i = 0; i < s->n_preferred_ciphers; i++) {
3881 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3882 if (!c) {
3883 s->warn = 1;
3884 } else {
3885 for (j = 0; j < c->nciphers; j++) {
3886 if (in_commasep_string(c->list[j]->name, str, len)) {
3887 s->sccipher_tobe = c->list[j];
3888 break;
3889 }
ca20bfcf 3890 }
32874aea 3891 }
51470298 3892 if (s->sccipher_tobe) {
3893 if (s->warn)
a8327734 3894 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
51470298 3895 break;
3896 }
32874aea 3897 }
51470298 3898 if (!s->sccipher_tobe) {
57356d63 3899 bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)",
3900 str ? str : "(null)"));
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 }
57356d63 4121 logeventf(ssh, "Initialised %.200s client->server encryption",
4122 ssh->cscipher->text_name);
4123 logeventf(ssh, "Initialised %.200s server->client encryption",
4124 ssh->sccipher->text_name);
4125 if (ssh->cscomp->text_name)
4126 logeventf(ssh, "Initialised %s compression",
4127 ssh->cscomp->text_name);
4128 if (ssh->sccomp->text_name)
4129 logeventf(ssh, "Initialised %s decompression",
4130 ssh->sccomp->text_name);
d39f364a 4131
033b4cef 4132 /*
0db56f73 4133 * If this is the first key exchange phase, we must pass the
4134 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4135 * wants to see it but because it will need time to initialise
4136 * itself before it sees an actual packet. In subsequent key
4137 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4138 * it would only confuse the layer above.
4139 */
51470298 4140 if (!s->first_kex) {
32874aea 4141 crReturn(0);
0db56f73 4142 }
51470298 4143 s->first_kex = 0;
0db56f73 4144
4145 /*
7cca0d81 4146 * Now we're encrypting. Begin returning 1 to the protocol main
4147 * function so that other things can run on top of the
4148 * transport. If we ever see a KEXINIT, we must go back to the
4149 * start.
033b4cef 4150 */
51470298 4151 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
32874aea 4152 crReturn(1);
e96adf72 4153 }
5e0d7cb8 4154 logevent("Server initiated key re-exchange");
7cca0d81 4155 goto begin_key_exchange;
e5574168 4156
4157 crFinish(1);
4158}
4159
7cca0d81 4160/*
783415f8 4161 * Add data to an SSH2 channel output buffer.
4162 */
32874aea 4163static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4164 int len)
4165{
5471d09a 4166 bufchain_add(&c->v.v2.outbuffer, buf, len);
783415f8 4167}
4168
4169/*
4170 * Attempt to send data on an SSH2 channel.
4171 */
5471d09a 4172static int ssh2_try_send(struct ssh_channel *c)
32874aea 4173{
51470298 4174 Ssh ssh = c->ssh;
4175
5471d09a 4176 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4177 int len;
4178 void *data;
4179 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4180 if ((unsigned)len > c->v.v2.remwindow)
4181 len = c->v.v2.remwindow;
4182 if ((unsigned)len > c->v.v2.remmaxpkt)
4183 len = c->v.v2.remmaxpkt;
51470298 4184 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4185 ssh2_pkt_adduint32(ssh, c->remoteid);
4186 ssh2_pkt_addstring_start(ssh);
4187 ssh2_pkt_addstring_data(ssh, data, len);
4188 ssh2_pkt_send(ssh);
5471d09a 4189 bufchain_consume(&c->v.v2.outbuffer, len);
4190 c->v.v2.remwindow -= len;
4191 }
4192
4193 /*
4194 * After having sent as much data as we can, return the amount
4195 * still buffered.
4196 */
4197 return bufchain_size(&c->v.v2.outbuffer);
4198}
4199
4200/*
4201 * Potentially enlarge the window on an SSH2 channel.
4202 */
4203static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4204{
51470298 4205 Ssh ssh = c->ssh;
4206
6b69f42e 4207 /*
4208 * Never send WINDOW_ADJUST for a channel that the remote side
4209 * already thinks it's closed; there's no point, since it won't
4210 * be sending any more data anyway.
4211 */
4212 if (c->closes != 0)
4213 return;
4214
5471d09a 4215 if (newwin > c->v.v2.locwindow) {
51470298 4216 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4217 ssh2_pkt_adduint32(ssh, c->remoteid);
4218 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4219 ssh2_pkt_send(ssh);
5471d09a 4220 c->v.v2.locwindow = newwin;
783415f8 4221 }
4222}
4223
4224/*
7cca0d81 4225 * Handle the SSH2 userauth and connection layers.
4226 */
51470298 4227static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
7cca0d81 4228{
51470298 4229 struct do_ssh2_authconn_state {
4230 enum {
4231 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4232 AUTH_PASSWORD,
4233 AUTH_KEYBOARD_INTERACTIVE
4234 } method;
4235 enum {
4236 AUTH_TYPE_NONE,
4237 AUTH_TYPE_PUBLICKEY,
4238 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4239 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4240 AUTH_TYPE_PASSWORD,
4241 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4242 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4243 } type;
4244 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4245 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4246 int kbd_inter_running;
4247 int we_are_in;
4248 int num_prompts, curr_prompt, echo;
4249 char username[100];
4250 int got_username;
4251 char pwprompt[200];
4252 char password[100];
4253 void *publickey_blob;
4254 int publickey_bloblen;
4255 unsigned char request[5], *response, *p;
4256 int responselen;
4257 int keyi, nkeys;
4258 int authed;
4259 char *pkblob, *alg, *commentp;
4260 int pklen, alglen, commentlen;
4261 int siglen, retlen, len;
4262 char *q, *agentreq, *ret;
4263 int try_send;
4264 };
4265 crState(do_ssh2_authconn_state);
4266
4267 crBegin(ssh->do_ssh2_authconn_crstate);
e5574168 4268
7cca0d81 4269 /*
4270 * Request userauth protocol, and await a response to it.
4271 */
51470298 4272 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4273 ssh2_pkt_addstring(ssh, "ssh-userauth");
4274 ssh2_pkt_send(ssh);
7cca0d81 4275 crWaitUntilV(ispkt);
51470298 4276 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
a8327734 4277 bombout((ssh,"Server refused user authentication protocol"));
32874aea 4278 crReturnV;
8d5de777 4279 }
7cca0d81 4280
4281 /*
1408a877 4282 * We repeat this whole loop, including the username prompt,
4283 * until we manage a successful authentication. If the user
51470298 4284 * types the wrong _password_, they can be sent back to the
4285 * beginning to try another username, if this is configured on.
4286 * (If they specify a username in the config, they are never
4287 * asked, even if they do give a wrong password.)
1408a877 4288 *
4289 * I think this best serves the needs of
4290 *
4291 * - the people who have no configuration, no keys, and just
4292 * want to try repeated (username,password) pairs until they
4293 * type both correctly
4294 *
4295 * - people who have keys and configuration but occasionally
4296 * need to fall back to passwords
4297 *
4298 * - people with a key held in Pageant, who might not have
4299 * logged in to a particular machine before; so they want to
4300 * type a username, and then _either_ their key will be
4301 * accepted, _or_ they will type a password. If they mistype
4302 * the username they will want to be able to get back and
4303 * retype it!
7cca0d81 4304 */
51470298 4305 s->username[0] = '\0';
4306 s->got_username = FALSE;
1408a877 4307 do {
1408a877 4308 /*
4309 * Get a username.
4310 */
51470298 4311 if (s->got_username && !cfg.change_username) {
5bb641e1 4312 /*
4313 * We got a username last time round this loop, and
4314 * with change_username turned off we don't try to get
4315 * it again.
4316 */
4317 } else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
c0a81592 4318 if (ssh_get_line && !ssh_getline_pw_only) {
32874aea 4319 if (!ssh_get_line("login as: ",
51470298 4320 s->username, sizeof(s->username), FALSE)) {
32874aea 4321 /*
4322 * get_line failed to get a username.
4323 * Terminate.
4324 */
4325 logevent("No username provided. Abandoning session.");
51470298 4326 ssh->state = SSH_STATE_CLOSED;
32874aea 4327 crReturnV;
4328 }
4329 } else {
51470298 4330 int ret; /* need not be saved across crReturn */
4331 c_write_str(ssh, "login as: ");
4332 ssh->send_ok = 1;
4333 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
0405e71f 4334 do {
32874aea 4335 crWaitUntilV(!ispkt);
51470298 4336 ret = process_userpass_input(ssh, in, inlen);
0405e71f 4337 } while (ret == 0);
4338 if (ret < 0)
4339 cleanup_exit(0);
4ca0c9d1 4340 c_write_str(ssh, "\r\n");
32874aea 4341 }
51470298 4342 s->username[strcspn(s->username, "\n\r")] = '\0';
7cca0d81 4343 } else {
57356d63 4344 char *stuff;
51470298 4345 strncpy(s->username, cfg.username, sizeof(s->username));
4346 s->username[sizeof(s->username)-1] = '\0';
65a22376 4347 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
57356d63 4348 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
51470298 4349 c_write_str(ssh, stuff);
57356d63 4350 sfree(stuff);
7cca0d81 4351 }
4352 }
51470298 4353 s->got_username = TRUE;
7cca0d81 4354
65a22376 4355 /*
1408a877 4356 * Send an authentication request using method "none": (a)
4357 * just in case it succeeds, and (b) so that we know what
4358 * authentication methods we can usefully try next.
65a22376 4359 */
51470298 4360 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4361
4362 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4363 ssh2_pkt_addstring(ssh, s->username);
4364 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4365 ssh2_pkt_addstring(ssh, "none"); /* method */
4366 ssh2_pkt_send(ssh);
4367 s->type = AUTH_TYPE_NONE;
4368 s->gotit = FALSE;
4369 s->we_are_in = FALSE;
4370
4371 s->tried_pubkey_config = FALSE;
4372 s->tried_agent = FALSE;
4373 s->tried_keyb_inter = FALSE;
4374 s->kbd_inter_running = FALSE;
396778f1 4375 /* Load the pub half of cfg.keyfile so we notice if it's in Pageant */
4376 if (*cfg.keyfile) {
231ee168 4377 int keytype;
a8327734 4378 logeventf(ssh->frontend,
4379 "Reading private key file \"%.150s\"", cfg.keyfile);
231ee168 4380 keytype = key_type(cfg.keyfile);
51470298 4381 if (keytype == SSH_KEYTYPE_SSH2) {
4382 s->publickey_blob =
4383 ssh2_userkey_loadpub(cfg.keyfile, NULL,
4384 &s->publickey_bloblen);
4385 } else {
57356d63 4386 char *msgbuf;
a8327734 4387 logeventf(ssh->frontend,
4388 "Unable to use this key file (%s)",
4389 key_type_to_str(keytype));
57356d63 4390 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4391 " (%s)\r\n", cfg.keyfile,
4392 key_type_to_str(keytype));
51470298 4393 c_write_str(ssh, msgbuf);
57356d63 4394 sfree(msgbuf);
51470298 4395 s->publickey_blob = NULL;
231ee168 4396 }
396778f1 4397 } else
51470298 4398 s->publickey_blob = NULL;
65a22376 4399
1408a877 4400 while (1) {
4401 /*
4402 * Wait for the result of the last authentication request.
4403 */
51470298 4404 if (!s->gotit)
1408a877 4405 crWaitUntilV(ispkt);
51470298 4406 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
32874aea 4407 char *banner;
4408 int size;
4409 /*
4410 * Don't show the banner if we're operating in
4411 * non-verbose non-interactive mode. (It's probably
4412 * a script, which means nobody will read the
4413 * banner _anyway_, and moreover the printing of
4414 * the banner will screw up processing on the
4415 * output of (say) plink.)
4416 */
4417 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
51470298 4418 ssh2_pkt_getstring(ssh, &banner, &size);
32874aea 4419 if (banner)
51470298 4420 c_write_untrusted(ssh, banner, size);
32874aea 4421 }
1408a877 4422 crWaitUntilV(ispkt);
4423 }
51470298 4424 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
1408a877 4425 logevent("Access granted");
51470298 4426 s->we_are_in = TRUE;
1408a877 4427 break;
4428 }
65a22376 4429
51470298 4430 if (s->kbd_inter_running &&
4431 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
b3186d64 4432 /*
45068b27 4433 * This is either a further set-of-prompts packet
4434 * in keyboard-interactive authentication, or it's
4435 * the same one and we came back here with `gotit'
4436 * set. In the former case, we must reset the
4437 * curr_prompt variable.
b3186d64 4438 */
51470298 4439 if (!s->gotit)
4440 s->curr_prompt = 0;
4441 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
a8327734 4442 bombout((ssh,"Strange packet received during authentication: type %d",
51470298 4443 ssh->pktin.type));
38c4a8da 4444 crReturnV;
65a22376 4445 }
4446
51470298 4447 s->gotit = FALSE;
65a22376 4448
1408a877 4449 /*
4450 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4451 * we can look at the string in it and know what we can
4452 * helpfully try next.
4453 */
51470298 4454 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
1408a877 4455 char *methods;
4456 int methlen;
51470298 4457 ssh2_pkt_getstring(ssh, &methods, &methlen);
4458 s->kbd_inter_running = FALSE;
4459 if (!ssh2_pkt_getbool(ssh)) {
1408a877 4460 /*
4461 * We have received an unequivocal Access
4462 * Denied. This can translate to a variety of
4463 * messages:
4464 *
4465 * - if we'd just tried "none" authentication,
4466 * it's not worth printing anything at all
4467 *
4468 * - if we'd just tried a public key _offer_,
4469 * the message should be "Server refused our
4470 * key" (or no message at all if the key
4471 * came from Pageant)
4472 *
4473 * - if we'd just tried anything else, the
4474 * message really should be "Access denied".
4475 *
4476 * Additionally, if we'd just tried password
4477 * authentication, we should break out of this
4478 * whole loop so as to go back to the username
4479 * prompt.
4480 */
51470298 4481 if (s->type == AUTH_TYPE_NONE) {
1408a877 4482 /* do nothing */
51470298 4483 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4484 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4485 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4486 c_write_str(ssh, "Server refused our key\r\n");
1408a877 4487 logevent("Server refused public key");
51470298 4488 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4bdf7c46 4489 /* server declined keyboard-interactive; ignore */
1408a877 4490 } else {
51470298 4491 c_write_str(ssh, "Access denied\r\n");
1408a877 4492 logevent("Access denied");
51470298 4493 if (s->type == AUTH_TYPE_PASSWORD) {
4494 s->we_are_in = FALSE;
1408a877 4495 break;
4496 }
4497 }
4498 } else {
51470298 4499 c_write_str(ssh, "Further authentication required\r\n");
1408a877 4500 logevent("Further authentication required");
4501 }
65a22376 4502
51470298 4503 s->can_pubkey =
32874aea 4504 in_commasep_string("publickey", methods, methlen);
51470298 4505 s->can_passwd =
32874aea 4506 in_commasep_string("password", methods, methlen);
51470298 4507 s->can_keyb_inter = cfg.try_ki_auth &&
761187b6 4508 in_commasep_string("keyboard-interactive", methods, methlen);
1408a877 4509 }
65a22376 4510
51470298 4511 s->method = 0;
4512 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
65a22376 4513
0405e71f 4514 /*
4515 * Most password/passphrase prompts will be
4516 * non-echoing, so we set this to 0 by default.
4517 * Exception is that some keyboard-interactive prompts
4518 * can be echoing, in which case we'll set this to 1.
4519 */
51470298 4520 s->echo = 0;
0405e71f 4521
51470298 4522 if (!s->method && s->can_pubkey &&
4523 agent_exists() && !s->tried_agent) {
1983e559 4524 /*
4525 * Attempt public-key authentication using Pageant.
4526 */
1983e559 4527 void *r;
51470298 4528 s->authed = FALSE;
1983e559 4529
51470298 4530 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4531 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
00db133f 4532
51470298 4533 s->tried_agent = TRUE;
1983e559 4534
4535 logevent("Pageant is running. Requesting keys.");
4536
4537 /* Request the keys held by the agent. */
51470298 4538 PUT_32BIT(s->request, 1);
4539 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4540 agent_query(s->request, 5, &r, &s->responselen);
4541 s->response = (unsigned char *) r;
4542 if (s->response && s->responselen >= 5 &&
4543 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4544 s->p = s->response + 5;
4545 s->nkeys = GET_32BIT(s->p);
4546 s->p += 4;
32874aea 4547 {
4548 char buf[64];
51470298 4549 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
32874aea 4550 logevent(buf);
4551 }
51470298 4552 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2d466ffd 4553 void *vret;
1983e559 4554
32874aea 4555 {
4556 char buf[64];
51470298 4557 sprintf(buf, "Trying Pageant key #%d", s->keyi);
32874aea 4558 logevent(buf);
4559 }
51470298 4560 s->pklen = GET_32BIT(s->p);
4561 s->p += 4;
4562 if (s->publickey_blob &&
4563 s->pklen == s->publickey_bloblen &&
4564 !memcmp(s->p, s->publickey_blob,
4565 s->publickey_bloblen)) {
396778f1 4566 logevent("This key matches configured key file");
51470298 4567 s->tried_pubkey_config = 1;
396778f1 4568 }
51470298 4569 s->pkblob = s->p;
4570 s->p += s->pklen;
4571 s->alglen = GET_32BIT(s->pkblob);
4572 s->alg = s->pkblob + 4;
4573 s->commentlen = GET_32BIT(s->p);
4574 s->p += 4;
4575 s->commentp = s->p;
4576 s->p += s->commentlen;
4577 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4578 ssh2_pkt_addstring(ssh, s->username);
4579 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4580 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4581 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4582 ssh2_pkt_addstring_start(ssh);
4583 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4584 ssh2_pkt_addstring_start(ssh);
4585 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4586 ssh2_pkt_send(ssh);
1983e559 4587
4588 crWaitUntilV(ispkt);
51470298 4589 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
1983e559 4590 logevent("Key refused");
4591 continue;
4592 }
4593
32874aea 4594 if (flags & FLAG_VERBOSE) {
51470298 4595 c_write_str(ssh, "Authenticating with "
4596 "public key \"");
4597 c_write(ssh, s->commentp, s->commentlen);
4598 c_write_str(ssh, "\" from agent\r\n");
32874aea 4599 }
1983e559 4600
4601 /*
4602 * Server is willing to accept the key.
4603 * Construct a SIGN_REQUEST.
4604 */
51470298 4605 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4606 ssh2_pkt_addstring(ssh, s->username);
4607 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4608 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4609 ssh2_pkt_addbool(ssh, TRUE);
4610 ssh2_pkt_addstring_start(ssh);
4611 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4612 ssh2_pkt_addstring_start(ssh);
4613 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4614
4615 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4616 s->len = 1; /* message type */
4617 s->len += 4 + s->pklen; /* key blob */
4618 s->len += 4 + s->siglen; /* data to sign */
4619 s->len += 4; /* flags */
4620 s->agentreq = smalloc(4 + s->len);
4621 PUT_32BIT(s->agentreq, s->len);
4622 s->q = s->agentreq + 4;
4623 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4624 PUT_32BIT(s->q, s->pklen);
4625 s->q += 4;
4626 memcpy(s->q, s->pkblob, s->pklen);
4627 s->q += s->pklen;
4628 PUT_32BIT(s->q, s->siglen);
4629 s->q += 4;
1983e559 4630 /* Now the data to be signed... */
51470298 4631 PUT_32BIT(s->q, 20);
4632 s->q += 4;
4633 memcpy(s->q, ssh->v2_session_id, 20);
4634 s->q += 20;
4635 memcpy(s->q, ssh->pktout.data + 5,
4636 ssh->pktout.length - 5);
4637 s->q += ssh->pktout.length - 5;
1983e559 4638 /* And finally the (zero) flags word. */
51470298 4639 PUT_32BIT(s->q, 0);
4640 agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
4641 s->ret = vret;
4642 sfree(s->agentreq);
4643 if (s->ret) {
4644 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
1983e559 4645 logevent("Sending Pageant's response");
51470298 4646 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4647 s->ret + 9,
4648 GET_32BIT(s->ret + 5));
4649 ssh2_pkt_send(ssh);
4650 s->authed = TRUE;
1983e559 4651 break;
4652 } else {
32874aea 4653 logevent
4654 ("Pageant failed to answer challenge");
51470298 4655 sfree(s->ret);
1983e559 4656 }
4657 }
4658 }
51470298 4659 if (s->authed)
1983e559 4660 continue;
4661 }
4662 }
4663
51470298 4664 if (!s->method && s->can_pubkey && s->publickey_blob
4665 && !s->tried_pubkey_config) {
1408a877 4666 unsigned char *pub_blob;
4667 char *algorithm, *comment;
4668 int pub_blob_len;
65a22376 4669
51470298 4670 s->tried_pubkey_config = TRUE;
65a22376 4671
51470298 4672 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4673 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
00db133f 4674
65a22376 4675 /*
1408a877 4676 * Try the public key supplied in the configuration.
4677 *
4678 * First, offer the public blob to see if the server is
4679 * willing to accept it.
65a22376 4680 */
1408a877 4681 pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
4682 &pub_blob_len);
4683 if (pub_blob) {
51470298 4684 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4685 ssh2_pkt_addstring(ssh, s->username);
4686 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4687 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4688 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4689 ssh2_pkt_addstring(ssh, algorithm);
4690 ssh2_pkt_addstring_start(ssh);
4691 ssh2_pkt_addstring_data(ssh, pub_blob, pub_blob_len);
4692 ssh2_pkt_send(ssh);
32874aea 4693 logevent("Offered public key"); /* FIXME */
1408a877 4694
4695 crWaitUntilV(ispkt);
51470298 4696 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4697 s->gotit = TRUE;
4698 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
32874aea 4699 continue; /* key refused; give up on it */
1408a877 4700 }
65a22376 4701
1408a877 4702 logevent("Offer of public key accepted");
65a22376 4703 /*
1408a877 4704 * Actually attempt a serious authentication using
4705 * the key.
65a22376 4706 */
1408a877 4707 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
51470298 4708 sprintf(s->pwprompt,
32874aea 4709 "Passphrase for key \"%.100s\": ",
4710 comment);
51470298 4711 s->need_pw = TRUE;
1408a877 4712 } else {
51470298 4713 s->need_pw = FALSE;
1408a877 4714 }
51470298 4715 c_write_str(ssh, "Authenticating with public key \"");
4716 c_write_str(ssh, comment);
4717 c_write_str(ssh, "\"\r\n");
4718 s->method = AUTH_PUBLICKEY_FILE;
65a22376 4719 }
1408a877 4720 }
4721
51470298 4722 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4723 s->method = AUTH_KEYBOARD_INTERACTIVE;
4724 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4725 s->tried_keyb_inter = TRUE;
af659722 4726
51470298 4727 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4728 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
00db133f 4729
51470298 4730 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4731 ssh2_pkt_addstring(ssh, s->username);
4732 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4733 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4734 ssh2_pkt_addstring(ssh, ""); /* lang */
4735 ssh2_pkt_addstring(ssh, "");
4736 ssh2_pkt_send(ssh);
af659722 4737
4738 crWaitUntilV(ispkt);
51470298 4739 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4740 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4741 s->gotit = TRUE;
af659722 4742 logevent("Keyboard-interactive authentication refused");
51470298 4743 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
af659722 4744 continue;
4745 }
4746
51470298 4747 s->kbd_inter_running = TRUE;
4748 s->curr_prompt = 0;
af659722 4749 }
4750
51470298 4751 if (s->kbd_inter_running) {
4752 s->method = AUTH_KEYBOARD_INTERACTIVE;
4753 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4754 s->tried_keyb_inter = TRUE;
af659722 4755
51470298 4756 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4757 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
00db133f 4758
51470298 4759 if (s->curr_prompt == 0) {
45068b27 4760 /*
4761 * We've got a fresh USERAUTH_INFO_REQUEST.
4762 * Display header data, and start going through
4763 * the prompts.
4764 */
4765 char *name, *inst, *lang;
4766 int name_len, inst_len, lang_len;
4767
51470298 4768 ssh2_pkt_getstring(ssh, &name, &name_len);
4769 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4770 ssh2_pkt_getstring(ssh, &lang, &lang_len);
45068b27 4771 if (name_len > 0) {
51470298 4772 c_write_untrusted(ssh, name, name_len);
4773 c_write_str(ssh, "\r\n");
45068b27 4774 }
4775 if (inst_len > 0) {
51470298 4776 c_write_untrusted(ssh, inst, inst_len);
4777 c_write_str(ssh, "\r\n");
45068b27 4778 }
51470298 4779 s->num_prompts = ssh2_pkt_getuint32(ssh);
45068b27 4780 }
af659722 4781
45068b27 4782 /*
4783 * If there are prompts remaining in the packet,
4784 * display one and get a response.
4785 */
51470298 4786 if (s->curr_prompt < s->num_prompts) {
45068b27 4787 char *prompt;
4788 int prompt_len;
af659722 4789
51470298 4790 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
45068b27 4791 if (prompt_len > 0) {
51470298 4792 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
4793 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
4794 prompt_len : sizeof(s->pwprompt)-1] = '\0';
45068b27 4795 } else {
51470298 4796 strcpy(s->pwprompt,
45068b27 4797 "<server failed to send prompt>: ");
4798 }
51470298 4799 s->echo = ssh2_pkt_getbool(ssh);
4800 s->need_pw = TRUE;
45068b27 4801 } else
51470298 4802 s->need_pw = FALSE;
af659722 4803 }
4804
51470298 4805 if (!s->method && s->can_passwd) {
4806 s->method = AUTH_PASSWORD;
4807 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4808 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4809 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
4810 ssh->savedhost);
4811 s->need_pw = TRUE;
1408a877 4812 }
4813
51470298 4814 if (s->need_pw) {
fa17a66e 4815 if (ssh_get_line) {
51470298 4816 if (!ssh_get_line(s->pwprompt, s->password,
4817 sizeof(s->password), TRUE)) {
1408a877 4818 /*
fa17a66e 4819 * get_line failed to get a password (for
4820 * example because one was supplied on the
4821 * command line which has already failed to
4822 * work). Terminate.
1408a877 4823 */
51470298 4824 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
4825 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
4826 ssh2_pkt_addstring(ssh, "No more passwords available"
4827 " to try");
4828 ssh2_pkt_addstring(ssh, "en"); /* language tag */
4829 ssh2_pkt_send(ssh);
247308b5 4830 logevent("Unable to authenticate");
a8327734 4831 connection_fatal(ssh->frontend,
4832 "Unable to authenticate");
51470298 4833 ssh->state = SSH_STATE_CLOSED;
1408a877 4834 crReturnV;
4835 }
4836 } else {
51470298 4837 int ret; /* need not be saved across crReturn */
4838 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
4839 ssh->send_ok = 1;
1408a877 4840
51470298 4841 setup_userpass_input(ssh, s->password,
4842 sizeof(s->password), s->echo);
0405e71f 4843 do {
1408a877 4844 crWaitUntilV(!ispkt);
51470298 4845 ret = process_userpass_input(ssh, in, inlen);
0405e71f 4846 } while (ret == 0);
4847 if (ret < 0)
4848 cleanup_exit(0);
51470298 4849 c_write_str(ssh, "\r\n");
65a22376 4850 }
65a22376 4851 }
65a22376 4852
51470298 4853 if (s->method == AUTH_PUBLICKEY_FILE) {
1408a877 4854 /*
4855 * We have our passphrase. Now try the actual authentication.
4856 */
4857 struct ssh2_userkey *key;
65a22376 4858
51470298 4859 key = ssh2_load_userkey(cfg.keyfile, s->password);
1408a877 4860 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4861 if (key == SSH2_WRONG_PASSPHRASE) {
51470298 4862 c_write_str(ssh, "Wrong passphrase\r\n");
4863 s->tried_pubkey_config = FALSE;
1408a877 4864 } else {
51470298 4865 c_write_str(ssh, "Unable to load private key\r\n");
4866 s->tried_pubkey_config = TRUE;
1408a877 4867 }
4868 /* Send a spurious AUTH_NONE to return to the top. */
51470298 4869 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4870 ssh2_pkt_addstring(ssh, s->username);
4871 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4872 ssh2_pkt_addstring(ssh, "none"); /* method */
4873 ssh2_pkt_send(ssh);
4874 s->type = AUTH_TYPE_NONE;
1408a877 4875 } else {
1dd353b5 4876 unsigned char *pkblob, *sigblob, *sigdata;
4877 int pkblob_len, sigblob_len, sigdata_len;
65a22376 4878
1408a877 4879 /*
4880 * We have loaded the private key and the server
4881 * has announced that it's willing to accept it.
4882 * Hallelujah. Generate a signature and send it.
4883 */
51470298 4884 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4885 ssh2_pkt_addstring(ssh, s->username);
4886 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4887 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4888 ssh2_pkt_addbool(ssh, TRUE);
4889 ssh2_pkt_addstring(ssh, key->alg->name);
1dd353b5 4890 pkblob = key->alg->public_blob(key->data, &pkblob_len);
51470298 4891 ssh2_pkt_addstring_start(ssh);
4892 ssh2_pkt_addstring_data(ssh, pkblob, pkblob_len);
1408a877 4893
4894 /*
4895 * The data to be signed is:
4896 *
4897 * string session-id
4898 *
4899 * followed by everything so far placed in the
4900 * outgoing packet.
4901 */
51470298 4902 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
1408a877 4903 sigdata = smalloc(sigdata_len);
4904 PUT_32BIT(sigdata, 20);
51470298 4905 memcpy(sigdata + 4, ssh->v2_session_id, 20);
4906 memcpy(sigdata + 24, ssh->pktout.data + 5,
4907 ssh->pktout.length - 5);
1dd353b5 4908 sigblob = key->alg->sign(key->data, sigdata,
4909 sigdata_len, &sigblob_len);
51470298 4910 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
1dd353b5 4911 sigblob, sigblob_len);
4912 sfree(pkblob);
4913 sfree(sigblob);
1408a877 4914 sfree(sigdata);
4915
51470298 4916 ssh2_pkt_send(ssh);
4917 s->type = AUTH_TYPE_PUBLICKEY;
1408a877 4918 }
51470298 4919 } else if (s->method == AUTH_PASSWORD) {
65a22376 4920 /*
1408a877 4921 * We send the password packet lumped tightly together with
4922 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4923 * string long enough to make the total length of the two
4924 * packets constant. This should ensure that a passive
4925 * listener doing traffic analyis can't work out the length
4926 * of the password.
4927 *
4928 * For this to work, we need an assumption about the
4929 * maximum length of the password packet. I think 256 is
4930 * pretty conservative. Anyone using a password longer than
4931 * that probably doesn't have much to worry about from
4932 * people who find out how long their password is!
65a22376 4933 */
51470298 4934 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4935 ssh2_pkt_addstring(ssh, s->username);
4936 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4937 ssh2_pkt_addstring(ssh, "password");
4938 ssh2_pkt_addbool(ssh, FALSE);
4939 ssh2_pkt_addstring(ssh, s->password);
4940 ssh2_pkt_defer(ssh);
65a22376 4941 /*
1408a877 4942 * We'll include a string that's an exact multiple of the
4943 * cipher block size. If the cipher is NULL for some
4944 * reason, we don't do this trick at all because we gain
4945 * nothing by it.
65a22376 4946 */
51470298 4947 if (ssh->cscipher) {
32874aea 4948 int stringlen, i;
4949
51470298 4950 stringlen = (256 - ssh->deferred_len);
4951 stringlen += ssh->cscipher->blksize - 1;
4952 stringlen -= (stringlen % ssh->cscipher->blksize);
4953 if (ssh->cscomp) {
32874aea 4954 /*
4955 * Temporarily disable actual compression,
4956 * so we can guarantee to get this string
4957 * exactly the length we want it. The
4958 * compression-disabling routine should
4959 * return an integer indicating how many
4960 * bytes we should adjust our string length
4961 * by.
4962 */
5366aed8 4963 stringlen -=
4964 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
32874aea 4965 }
51470298 4966 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
4967 ssh2_pkt_addstring_start(ssh);
6e9e9520 4968 for (i = 0; i < stringlen; i++) {
32874aea 4969 char c = (char) random_byte();
51470298 4970 ssh2_pkt_addstring_data(ssh, &c, 1);
65a22376 4971 }
51470298 4972 ssh2_pkt_defer(ssh);
65a22376 4973 }
51470298 4974 ssh_pkt_defersend(ssh);
0d43337a 4975 logevent("Sent password");
51470298 4976 s->type = AUTH_TYPE_PASSWORD;
4977 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
4978 if (s->curr_prompt == 0) {
4979 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
4980 ssh2_pkt_adduint32(ssh, s->num_prompts);
45068b27 4981 }
51470298 4982 if (s->need_pw) { /* only add pw if we just got one! */
4983 ssh2_pkt_addstring(ssh, s->password);
4984 memset(s->password, 0, sizeof(s->password));
4985 s->curr_prompt++;
45068b27 4986 }
51470298 4987 if (s->curr_prompt >= s->num_prompts) {
4988 ssh2_pkt_send(ssh);
45068b27 4989 } else {
4990 /*
4991 * If there are prompts remaining, we set
4992 * `gotit' so that we won't attempt to get
4993 * another packet. Then we go back round the
4994 * loop and will end up retrieving another
4995 * prompt out of the existing packet. Funky or
4996 * what?
4997 */
51470298 4998 s->gotit = TRUE;
45068b27 4999 }
51470298 5000 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
1408a877 5001 } else {
51470298 5002 c_write_str(ssh, "No supported authentication methods"
5003 " left to try!\r\n");
5004 logevent("No supported authentications offered."
5005 " Disconnecting");
5006 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5007 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5008 ssh2_pkt_addstring(ssh, "No supported authentication"
5009 " methods available");
5010 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5011 ssh2_pkt_send(ssh);
5012 ssh->state = SSH_STATE_CLOSED;
1408a877 5013 crReturnV;
65a22376 5014 }
65a22376 5015 }
51470298 5016 } while (!s->we_are_in);
7cca0d81 5017
5018 /*
5019 * Now we're authenticated for the connection protocol. The
5020 * connection protocol will automatically have started at this
5021 * point; there's no need to send SERVICE_REQUEST.
5022 */
5023
5024 /*
5025 * So now create a channel with a session in it.
5026 */
51470298 5027 ssh->channels = newtree234(ssh_channelcmp);
5028 ssh->mainchan = smalloc(sizeof(struct ssh_channel));
5029 ssh->mainchan->ssh = ssh;
5030 ssh->mainchan->localid = alloc_channel_id(ssh);
5031 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5032 ssh2_pkt_addstring(ssh, "session");
5033 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5034 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5035 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5036 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5037 ssh2_pkt_send(ssh);
7cca0d81 5038 crWaitUntilV(ispkt);
51470298 5039 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
a8327734 5040 bombout((ssh,"Server refused to open a session"));
32874aea 5041 crReturnV;
5042 /* FIXME: error data comes back in FAILURE packet */
7cca0d81 5043 }
51470298 5044 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
a8327734 5045 bombout((ssh,"Server's channel confirmation cited wrong channel"));
32874aea 5046 crReturnV;
7cca0d81 5047 }
51470298 5048 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5049 ssh->mainchan->type = CHAN_MAINSESSION;
5050 ssh->mainchan->closes = 0;
5051 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5052 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5053 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5054 add234(ssh->channels, ssh->mainchan);
7cca0d81 5055 logevent("Opened channel for session");
5056
5057 /*
783415f8 5058 * Potentially enable X11 forwarding.
5059 */
5060 if (cfg.x11_forward) {
32874aea 5061 char proto[20], data[64];
5062 logevent("Requesting X11 forwarding");
302121de 5063 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5064 data, sizeof(data));
51470298 5065 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5066 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5067 ssh2_pkt_addstring(ssh, "x11-req");
5068 ssh2_pkt_addbool(ssh, 1); /* want reply */
5069 ssh2_pkt_addbool(ssh, 0); /* many connections */
5070 ssh2_pkt_addstring(ssh, proto);
5071 ssh2_pkt_addstring(ssh, data);
5072 ssh2_pkt_adduint32(ssh, 0); /* screen number */
5073 ssh2_pkt_send(ssh);
32874aea 5074
5075 do {
5076 crWaitUntilV(ispkt);
51470298 5077 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5078 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5079 struct ssh_channel *c;
51470298 5080 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5081 if (!c)
5082 continue; /* nonexistent channel */
51470298 5083 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
32874aea 5084 }
51470298 5085 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
32874aea 5086
51470298 5087 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5088 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
a8327734 5089 bombout((ssh,"Unexpected response to X11 forwarding request:"
51470298 5090 " packet type %d", ssh->pktin.type));
32874aea 5091 crReturnV;
5092 }
5093 logevent("X11 forwarding refused");
5094 } else {
5095 logevent("X11 forwarding enabled");
51470298 5096 ssh->X11_fwd_enabled = TRUE;
32874aea 5097 }
783415f8 5098 }
5099
5100 /*
bc240b21 5101 * Enable port forwardings.
5102 */
5103 {
bc240b21 5104 char type;
5105 int n;
a4fc0d74 5106 int sport,dport,sserv,dserv;
bc240b21 5107 char sports[256], dports[256], host[256];
bc240b21 5108
51470298 5109 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
bc240b21 5110 /* Add port forwardings. */
51470298 5111 ssh->portfwd_strptr = cfg.portfwd;
5112 while (*ssh->portfwd_strptr) {
5113 type = *ssh->portfwd_strptr++;
bc240b21 5114 n = 0;
51470298 5115 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t')
5116 sports[n++] = *ssh->portfwd_strptr++;
bc240b21 5117 sports[n] = 0;
51470298 5118 if (*ssh->portfwd_strptr == '\t')
5119 ssh->portfwd_strptr++;
bc240b21 5120 n = 0;
51470298 5121 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':')
5122 host[n++] = *ssh->portfwd_strptr++;
bc240b21 5123 host[n] = 0;
51470298 5124 if (*ssh->portfwd_strptr == ':')
5125 ssh->portfwd_strptr++;
bc240b21 5126 n = 0;
51470298 5127 while (*ssh->portfwd_strptr)
5128 dports[n++] = *ssh->portfwd_strptr++;
bc240b21 5129 dports[n] = 0;
51470298 5130 ssh->portfwd_strptr++;
bc240b21 5131 dport = atoi(dports);
a4fc0d74 5132 dserv = 0;
5133 if (dport == 0) {
5134 dserv = 1;
68a49acb 5135 dport = net_service_lookup(dports);
5136 if (!dport) {
57356d63 5137 logeventf(ssh, "Service lookup failed for destination"
5138 " port \"%s\"", dports);
a4fc0d74 5139 }
5140 }
bc240b21 5141 sport = atoi(sports);
a4fc0d74 5142 sserv = 0;
5143 if (sport == 0) {
5144 sserv = 1;
68a49acb 5145 sport = net_service_lookup(sports);
5146 if (!sport) {
57356d63 5147 logeventf(ssh, "Service lookup failed for source"
5148 " port \"%s\"", sports);
a4fc0d74 5149 }
5150 }
bc240b21 5151 if (sport && dport) {
5152 if (type == 'L') {
6b78788a 5153 pfd_addforward(host, dport, sport, ssh);
57356d63 5154 logeventf(ssh, "Local port %.*s%.*s%d%.*s forwarding to"
5155 " %s:%.*s%.*s%d%.*s",
5156 (int)(sserv ? strlen(sports) : 0), sports,
5157 sserv, "(", sport, sserv, ")",
5158 host,
5159 (int)(dserv ? strlen(dports) : 0), dports,
5160 dserv, "(", dport, dserv, ")");
bc240b21 5161 } else {
5162 struct ssh_rportfwd *pf;
5163 pf = smalloc(sizeof(*pf));
5164 strcpy(pf->dhost, host);
5165 pf->dport = dport;
5166 pf->sport = sport;
51470298 5167 if (add234(ssh->rportfwds, pf) != pf) {
57356d63 5168 logeventf(ssh, "Duplicate remote port forwarding"
5169 " to %s:%d", host, dport);
bc240b21 5170 sfree(pf);
5171 } else {
57356d63 5172 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
5173 " forward to %s:%.*s%.*s%d%.*s",
5174 (int)(sserv ? strlen(sports) : 0), sports,
5175 sserv, "(", sport, sserv, ")",
5176 host,
5177 (int)(dserv ? strlen(dports) : 0), dports,
5178 dserv, "(", dport, dserv, ")");
51470298 5179 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5180 ssh2_pkt_addstring(ssh, "tcpip-forward");
5181 ssh2_pkt_addbool(ssh, 1);/* want reply */
beefa433 5182 if (cfg.rport_acceptall)
51470298 5183 ssh2_pkt_addstring(ssh, "0.0.0.0");
beefa433 5184 else
51470298 5185 ssh2_pkt_addstring(ssh, "127.0.0.1");
5186 ssh2_pkt_adduint32(ssh, sport);
5187 ssh2_pkt_send(ssh);
bc240b21 5188
5189 do {
5190 crWaitUntilV(ispkt);
51470298 5191 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5192 unsigned i = ssh2_pkt_getuint32(ssh);
bc240b21 5193 struct ssh_channel *c;
51470298 5194 c = find234(ssh->channels, &i, ssh_channelfind);
bc240b21 5195 if (!c)
5196 continue;/* nonexistent channel */
51470298 5197 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
bc240b21 5198 }
51470298 5199 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
bc240b21 5200
51470298 5201 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5202 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
a8327734 5203 bombout((ssh,"Unexpected response to port "
c9886e66 5204 "forwarding request: packet type %d",
51470298 5205 ssh->pktin.type));
bc240b21 5206 crReturnV;
5207 }
5208 logevent("Server refused this port forwarding");
5209 } else {
5210 logevent("Remote port forwarding enabled");
5211 }
5212 }
5213 }
5214 }
5215 }
5216 }
5217
5218 /*
36c2a3e9 5219 * Potentially enable agent forwarding.
5220 */
5221 if (cfg.agentfwd && agent_exists()) {
32874aea 5222 logevent("Requesting OpenSSH-style agent forwarding");
51470298 5223 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5224 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5225 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5226 ssh2_pkt_addbool(ssh, 1); /* want reply */
5227 ssh2_pkt_send(ssh);
32874aea 5228
5229 do {
5230 crWaitUntilV(ispkt);
51470298 5231 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5232 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5233 struct ssh_channel *c;
51470298 5234 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5235 if (!c)
5236 continue; /* nonexistent channel */
51470298 5237 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
32874aea 5238 }
51470298 5239 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
32874aea 5240
51470298 5241 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5242 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
a8327734 5243 bombout((ssh,"Unexpected response to agent forwarding request:"
51470298 5244 " packet type %d", ssh->pktin.type));
32874aea 5245 crReturnV;
5246 }
5247 logevent("Agent forwarding refused");
5248 } else {
5249 logevent("Agent forwarding enabled");
51470298 5250 ssh->agentfwd_enabled = TRUE;
32874aea 5251 }
36c2a3e9 5252 }
5253
5254 /*
7cca0d81 5255 * Now allocate a pty for the session.
5256 */
67779be7 5257 if (!cfg.nopty) {
51470298 5258 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5259 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5260 ssh2_pkt_addstring(ssh, "pty-req");
5261 ssh2_pkt_addbool(ssh, 1); /* want reply */
5262 ssh2_pkt_addstring(ssh, cfg.termtype);
5263 ssh2_pkt_adduint32(ssh, ssh->term_width);
5264 ssh2_pkt_adduint32(ssh, ssh->term_height);
5265 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5266 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5267 ssh2_pkt_addstring_start(ssh);
5268 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5269 ssh2_pkt_send(ssh);
5270 ssh->state = SSH_STATE_INTERMED;
32874aea 5271
5272 do {
5273 crWaitUntilV(ispkt);
51470298 5274 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5275 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5276 struct ssh_channel *c;
51470298 5277 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5278 if (!c)
5279 continue; /* nonexistent channel */
51470298 5280 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
32874aea 5281 }
51470298 5282 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
32874aea 5283
51470298 5284 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5285 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
a8327734 5286 bombout((ssh,"Unexpected response to pty request:"
51470298 5287 " packet type %d", ssh->pktin.type));
32874aea 5288 crReturnV;
5289 }
51470298 5290 c_write_str(ssh, "Server refused to allocate pty\r\n");
5291 ssh->editing = ssh->echoing = 1;
32874aea 5292 } else {
5293 logevent("Allocated pty");
5294 }
0965bee0 5295 } else {
51470298 5296 ssh->editing = ssh->echoing = 1;
7cca0d81 5297 }
5298
5299 /*
fd5e5847 5300 * Start a shell or a remote command. We may have to attempt
5301 * this twice if the config data has provided a second choice
5302 * of command.
7cca0d81 5303 */
fd5e5847 5304 while (1) {
5305 int subsys;
5306 char *cmd;
5307
51470298 5308 if (ssh->fallback_cmd) {
fd5e5847 5309 subsys = cfg.ssh_subsys2;
5310 cmd = cfg.remote_cmd_ptr2;
5311 } else {
5312 subsys = cfg.ssh_subsys;
5313 cmd = cfg.remote_cmd_ptr;
5314 }
5315
51470298 5316 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5317 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
fd5e5847 5318 if (subsys) {
51470298 5319 ssh2_pkt_addstring(ssh, "subsystem");
5320 ssh2_pkt_addbool(ssh, 1); /* want reply */
5321 ssh2_pkt_addstring(ssh, cmd);
fd5e5847 5322 } else if (*cmd) {
51470298 5323 ssh2_pkt_addstring(ssh, "exec");
5324 ssh2_pkt_addbool(ssh, 1); /* want reply */
5325 ssh2_pkt_addstring(ssh, cmd);
fd5e5847 5326 } else {
51470298 5327 ssh2_pkt_addstring(ssh, "shell");
5328 ssh2_pkt_addbool(ssh, 1); /* want reply */
32874aea 5329 }
51470298 5330 ssh2_pkt_send(ssh);
fd5e5847 5331 do {
5332 crWaitUntilV(ispkt);
51470298 5333 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5334 unsigned i = ssh2_pkt_getuint32(ssh);
fd5e5847 5335 struct ssh_channel *c;
51470298 5336 c = find234(ssh->channels, &i, ssh_channelfind);
fd5e5847 5337 if (!c)
5338 continue; /* nonexistent channel */
51470298 5339 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
fd5e5847 5340 }
51470298 5341 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5342 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5343 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
a8327734 5344 bombout((ssh,"Unexpected response to shell/command request:"
51470298 5345 " packet type %d", ssh->pktin.type));
fd5e5847 5346 crReturnV;
5347 }
5348 /*
5349 * We failed to start the command. If this is the
5350 * fallback command, we really are finished; if it's
5351 * not, and if the fallback command exists, try falling
5352 * back to it before complaining.
5353 */
51470298 5354 if (!ssh->fallback_cmd && cfg.remote_cmd_ptr2 != NULL) {
fd5e5847 5355 logevent("Primary command failed; attempting fallback");
51470298 5356 ssh->fallback_cmd = TRUE;
fd5e5847 5357 continue;
5358 }
a8327734 5359 bombout((ssh,"Server refused to start a shell/command"));
32874aea 5360 crReturnV;
fd5e5847 5361 } else {
5362 logevent("Started a shell/command");
32874aea 5363 }
fd5e5847 5364 break;
7cca0d81 5365 }
5366
51470298 5367 ssh->state = SSH_STATE_SESSION;
5368 if (ssh->size_needed)
5369 ssh_size(ssh, ssh->term_width, ssh->term_height);
5370 if (ssh->eof_needed)
5371 ssh_special(ssh, TS_EOF);
6e48c3fe 5372
7cca0d81 5373 /*
5374 * Transfer data!
5375 */
b9d7bcad 5376 if (ssh->ldisc)
5377 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
51470298 5378 ssh->send_ok = 1;
7cca0d81 5379 while (1) {
e5574168 5380 crReturnV;
51470298 5381 s->try_send = FALSE;
7cca0d81 5382 if (ispkt) {
51470298 5383 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5384 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
32874aea 5385 char *data;
5386 int length;
51470298 5387 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5388 struct ssh_channel *c;
51470298 5389 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5390 if (!c)
5391 continue; /* nonexistent channel */
51470298 5392 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5393 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
32874aea 5394 continue; /* extended but not stderr */
51470298 5395 ssh2_pkt_getstring(ssh, &data, &length);
32874aea 5396 if (data) {
5471d09a 5397 int bufsize;
5398 c->v.v2.locwindow -= length;
32874aea 5399 switch (c->type) {
5400 case CHAN_MAINSESSION:
5471d09a 5401 bufsize =
51470298 5402 from_backend(ssh->frontend, ssh->pktin.type ==
5471d09a 5403 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5404 data, length);
32874aea 5405 break;
5406 case CHAN_X11:
5471d09a 5407 bufsize = x11_send(c->u.x11.s, data, length);
32874aea 5408 break;
d74d141c 5409 case CHAN_SOCKDATA:
5471d09a 5410 bufsize = pfd_send(c->u.pfd.s, data, length);
bc240b21 5411 break;
36c2a3e9 5412 case CHAN_AGENT:
32874aea 5413 while (length > 0) {
5414 if (c->u.a.lensofar < 4) {
5415 int l = min(4 - c->u.a.lensofar, length);
5416 memcpy(c->u.a.msglen + c->u.a.lensofar,
5417 data, l);
5418 data += l;
5419 length -= l;
5420 c->u.a.lensofar += l;
5421 }
5422 if (c->u.a.lensofar == 4) {
5423 c->u.a.totallen =
5424 4 + GET_32BIT(c->u.a.msglen);
5425 c->u.a.message = smalloc(c->u.a.totallen);
5426 memcpy(c->u.a.message, c->u.a.msglen, 4);
5427 }
5428 if (c->u.a.lensofar >= 4 && length > 0) {
5429 int l =
5430 min(c->u.a.totallen - c->u.a.lensofar,
5431 length);
5432 memcpy(c->u.a.message + 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 == c->u.a.totallen) {
5439 void *reply, *sentreply;
5440 int replylen;
5441 agent_query(c->u.a.message,
5442 c->u.a.totallen, &reply,
5443 &replylen);
5444 if (reply)
5445 sentreply = reply;
5446 else {
5447 /* Fake SSH_AGENT_FAILURE. */
5448 sentreply = "\0\0\0\1\5";
5449 replylen = 5;
5450 }
51470298 5451 ssh2_add_channel_data(c, sentreply, replylen);
5452 s->try_send = TRUE;
32874aea 5453 if (reply)
5454 sfree(reply);
5455 sfree(c->u.a.message);
5456 c->u.a.lensofar = 0;
5457 }
5458 }
5471d09a 5459 bufsize = 0;
32874aea 5460 break;
5461 }
5462 /*
5471d09a 5463 * If we are not buffering too much data,
5464 * enlarge the window again at the remote side.
32874aea 5465 */
5471d09a 5466 if (bufsize < OUR_V2_WINSIZE)
5467 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
32874aea 5468 }
51470298 5469 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5470 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5471 struct ssh_channel *c;
5472
51470298 5473 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5474 if (!c)
5475 continue; /* nonexistent channel */
5476
5477 if (c->type == CHAN_X11) {
5478 /*
5479 * Remote EOF on an X11 channel means we should
5480 * wrap up and close the channel ourselves.
5481 */
5482 x11_close(c->u.x11.s);
5483 sshfwd_close(c);
5484 } else if (c->type == CHAN_AGENT) {
36c2a3e9 5485 sshfwd_close(c);
d74d141c 5486 } else if (c->type == CHAN_SOCKDATA) {
bc240b21 5487 pfd_close(c->u.pfd.s);
5488 sshfwd_close(c);
36c2a3e9 5489 }
51470298 5490 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5491 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5492 struct ssh_channel *c;
5493
51470298 5494 c = find234(ssh->channels, &i, ssh_channelfind);
d0d844c1 5495 if (!c || ((int)c->remoteid) == -1) {
a8327734 5496 bombout((ssh,"Received CHANNEL_CLOSE for %s channel %d\n",
d0d844c1 5497 c ? "half-open" : "nonexistent", i));
5498 }
32874aea 5499 /* Do pre-close processing on the channel. */
5500 switch (c->type) {
5501 case CHAN_MAINSESSION:
5502 break; /* nothing to see here, move along */
5503 case CHAN_X11:
92f157bd 5504 if (c->u.x11.s != NULL)
5505 x11_close(c->u.x11.s);
5506 sshfwd_close(c);
32874aea 5507 break;
5508 case CHAN_AGENT:
92f157bd 5509 sshfwd_close(c);
32874aea 5510 break;
d74d141c 5511 case CHAN_SOCKDATA:
92f157bd 5512 if (c->u.pfd.s != NULL)
5513 pfd_close(c->u.pfd.s);
5514 sshfwd_close(c);
bc240b21 5515 break;
32874aea 5516 }
92f157bd 5517 if (c->closes == 0) {
51470298 5518 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5519 ssh2_pkt_adduint32(ssh, c->remoteid);
5520 ssh2_pkt_send(ssh);
92f157bd 5521 }
51470298 5522 del234(ssh->channels, c);
5471d09a 5523 bufchain_clear(&c->v.v2.outbuffer);
32874aea 5524 sfree(c);
5525
5526 /*
5527 * See if that was the last channel left open.
5528 */
51470298 5529 if (count234(ssh->channels) == 0) {
ca2914d1 5530#if 0
5531 /*
5532 * We used to send SSH_MSG_DISCONNECT here,
5533 * because I'd believed that _every_ conforming
5534 * SSH2 connection had to end with a disconnect
5535 * being sent by at least one side; apparently
5536 * I was wrong and it's perfectly OK to
5537 * unceremoniously slam the connection shut
5538 * when you're done, and indeed OpenSSH feels
5539 * this is more polite than sending a
5540 * DISCONNECT. So now we don't.
5541 */
32874aea 5542 logevent("All channels closed. Disconnecting");
51470298 5543 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5544 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5545 ssh2_pkt_addstring(ssh, "All open channels closed");
5546 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5547 ssh2_pkt_send(ssh);
ca2914d1 5548#endif
51470298 5549 ssh->state = SSH_STATE_CLOSED;
32874aea 5550 crReturnV;
5551 }
5552 continue; /* remote sends close; ignore (FIXME) */
51470298 5553 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5554 unsigned i = ssh2_pkt_getuint32(ssh);
32874aea 5555 struct ssh_channel *c;
51470298 5556 c = find234(ssh->channels, &i, ssh_channelfind);
32874aea 5557 if (!c)
5558 continue; /* nonexistent channel */
51470298 5559 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5560 s->try_send = TRUE;
5561 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5562 unsigned i = ssh2_pkt_getuint32(ssh);
bc240b21 5563 struct ssh_channel *c;
51470298 5564 c = find234(ssh->channels, &i, ssh_channelfind);
bc240b21 5565 if (!c)
5566 continue; /* nonexistent channel */
5567 if (c->type != CHAN_SOCKDATA_DORMANT)
5568 continue; /* dunno why they're confirming this */
51470298 5569 c->remoteid = ssh2_pkt_getuint32(ssh);
bc240b21 5570 c->type = CHAN_SOCKDATA;
51470298 5571 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5572 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
4ed34d25 5573 if (c->u.pfd.s)
5574 pfd_confirm(c->u.pfd.s);
5575 if (c->closes) {
5576 /*
5577 * We have a pending close on this channel,
5578 * which we decided on before the server acked
5579 * the channel open. So now we know the
5580 * remoteid, we can close it again.
5581 */
51470298 5582 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5583 ssh2_pkt_adduint32(ssh, c->remoteid);
5584 ssh2_pkt_send(ssh);
4ed34d25 5585 }
51470298 5586 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5587 unsigned i = ssh2_pkt_getuint32(ssh);
724cface 5588 struct ssh_channel *c;
51470298 5589 c = find234(ssh->channels, &i, ssh_channelfind);
724cface 5590 if (!c)
5591 continue; /* nonexistent channel */
5592 if (c->type != CHAN_SOCKDATA_DORMANT)
5593 continue; /* dunno why they're failing this */
5594
5595 logevent("Forwarded connection refused by server");
5596
5597 pfd_close(c->u.pfd.s);
5598
51470298 5599 del234(ssh->channels, c);
724cface 5600 sfree(c);
51470298 5601 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
ebb0a590 5602 unsigned localid;
5603 char *type;
5604 int typelen, want_reply;
5605 struct ssh_channel *c;
5606
51470298 5607 localid = ssh2_pkt_getuint32(ssh);
5608 ssh2_pkt_getstring(ssh, &type, &typelen);
5609 want_reply = ssh2_pkt_getbool(ssh);
ebb0a590 5610
5611 /*
5612 * First, check that the channel exists. Otherwise,
5613 * we can instantly disconnect with a rude message.
5614 */
51470298 5615 c = find234(ssh->channels, &localid, ssh_channelfind);
ebb0a590 5616 if (!c) {
5617 char buf[80];
5618 sprintf(buf, "Received channel request for nonexistent"
5619 " channel %d", localid);
5620 logevent(buf);
51470298 5621 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5622 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5623 ssh2_pkt_addstring(ssh, buf);
5624 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5625 ssh2_pkt_send(ssh);
247308b5 5626 connection_fatal("%s", buf);
51470298 5627 ssh->state = SSH_STATE_CLOSED;
ebb0a590 5628 crReturnV;
5629 }
5630
5631 /*
d8d6c7e5 5632 * Having got the channel number, we now look at
5633 * the request type string to see if it's something
5634 * we recognise.
ebb0a590 5635 */
d8d6c7e5 5636 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
51470298 5637 c == ssh->mainchan) {
d8d6c7e5 5638 /* We recognise "exit-status" on the primary channel. */
5639 char buf[100];
51470298 5640 ssh->exitcode = ssh2_pkt_getuint32(ssh);
d8d6c7e5 5641 sprintf(buf, "Server sent command exit status %d",
51470298 5642 ssh->exitcode);
d8d6c7e5 5643 logevent(buf);
5644 if (want_reply) {
51470298 5645 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5646 ssh2_pkt_adduint32(ssh, c->remoteid);
5647 ssh2_pkt_send(ssh);
d8d6c7e5 5648 }
5649 } else {
5650 /*
5651 * This is a channel request we don't know
5652 * about, so we now either ignore the request
5653 * or respond with CHANNEL_FAILURE, depending
5654 * on want_reply.
5655 */
5656 if (want_reply) {
51470298 5657 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5658 ssh2_pkt_adduint32(ssh, c->remoteid);
5659 ssh2_pkt_send(ssh);
d8d6c7e5 5660 }
ebb0a590 5661 }
51470298 5662 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
697d4856 5663 char *type;
5664 int typelen, want_reply;
5665
51470298 5666 ssh2_pkt_getstring(ssh, &type, &typelen);
5667 want_reply = ssh2_pkt_getbool(ssh);
697d4856 5668
5669 /*
5670 * We currently don't support any global requests
5671 * at all, so we either ignore the request or
5672 * respond with REQUEST_FAILURE, depending on
5673 * want_reply.
5674 */
5675 if (want_reply) {
51470298 5676 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5677 ssh2_pkt_send(ssh);
697d4856 5678 }
51470298 5679 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
32874aea 5680 char *type;
5681 int typelen;
5682 char *error = NULL;
5683 struct ssh_channel *c;
bc240b21 5684 unsigned remid, winsize, pktsize;
51470298 5685 ssh2_pkt_getstring(ssh, &type, &typelen);
32874aea 5686 c = smalloc(sizeof(struct ssh_channel));
51470298 5687 c->ssh = ssh;
32874aea 5688
51470298 5689 remid = ssh2_pkt_getuint32(ssh);
5690 winsize = ssh2_pkt_getuint32(ssh);
5691 pktsize = ssh2_pkt_getuint32(ssh);
bc240b21 5692
32874aea 5693 if (typelen == 3 && !memcmp(type, "x11", 3)) {
51470298 5694 if (!ssh->X11_fwd_enabled)
32874aea 5695 error = "X11 forwarding is not enabled";
302121de 5696 else if (x11_init(&c->u.x11.s, cfg.x11_display, c,
5697 ssh->x11auth) != NULL) {
32874aea 5698 error = "Unable to open an X11 connection";
5699 } else {
5700 c->type = CHAN_X11;
5701 }
bc240b21 5702 } else if (typelen == 15 &&
5703 !memcmp(type, "forwarded-tcpip", 15)) {
5704 struct ssh_rportfwd pf, *realpf;
5705 char *dummy;
5706 int dummylen;
51470298 5707 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5708 pf.sport = ssh2_pkt_getuint32(ssh);
5709 realpf = find234(ssh->rportfwds, &pf, NULL);
bc240b21 5710 if (realpf == NULL) {
5711 error = "Remote port is not recognised";
5712 } else {
5713 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5714 realpf->dport, c);
57356d63 5715 logeventf(ssh, "Received remote port open request"
5716 " for %s:%d", realpf->dhost, realpf->dport);
bc240b21 5717 if (e != NULL) {
57356d63 5718 logeventf(ssh, "Port open failed: %s", e);
bc240b21 5719 error = "Port open failed";
5720 } else {
5721 logevent("Forwarded port opened successfully");
5722 c->type = CHAN_SOCKDATA;
5723 }
5724 }
32874aea 5725 } else if (typelen == 22 &&
36c2a3e9 5726 !memcmp(type, "auth-agent@openssh.com", 3)) {
51470298 5727 if (!ssh->agentfwd_enabled)
32874aea 5728 error = "Agent forwarding is not enabled";
36c2a3e9 5729 else {
32874aea 5730 c->type = CHAN_AGENT; /* identify channel type */
36c2a3e9 5731 c->u.a.lensofar = 0;
32874aea 5732 }
5733 } else {
5734 error = "Unsupported channel type requested";
5735 }
5736
bc240b21 5737 c->remoteid = remid;
32874aea 5738 if (error) {
51470298 5739 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
5740 ssh2_pkt_adduint32(ssh, c->remoteid);
5741 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
5742 ssh2_pkt_addstring(ssh, error);
5743 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5744 ssh2_pkt_send(ssh);
32874aea 5745 sfree(c);
5746 } else {
51470298 5747 c->localid = alloc_channel_id(ssh);
32874aea 5748 c->closes = 0;
5471d09a 5749 c->v.v2.locwindow = OUR_V2_WINSIZE;
5750 c->v.v2.remwindow = winsize;
5751 c->v.v2.remmaxpkt = pktsize;
5752 bufchain_init(&c->v.v2.outbuffer);
51470298 5753 add234(ssh->channels, c);
5754 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5755 ssh2_pkt_adduint32(ssh, c->remoteid);
5756 ssh2_pkt_adduint32(ssh, c->localid);
5757 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
5758 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5759 ssh2_pkt_send(ssh);
32874aea 5760 }
7cca0d81 5761 } else {
a8327734 5762 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
32874aea 5763 crReturnV;
7cca0d81 5764 }
5765 } else {
32874aea 5766 /*
5767 * We have spare data. Add it to the channel buffer.
5768 */
51470298 5769 ssh2_add_channel_data(ssh->mainchan, in, inlen);
5770 s->try_send = TRUE;
32874aea 5771 }
51470298 5772 if (s->try_send) {
32874aea 5773 int i;
5774 struct ssh_channel *c;
5775 /*
5776 * Try to send data on all channels if we can.
5777 */
51470298 5778 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5471d09a 5779 int bufsize = ssh2_try_send(c);
5780 if (bufsize == 0) {
5781 switch (c->type) {
5782 case CHAN_MAINSESSION:
5783 /* stdin need not receive an unthrottle
5784 * notification since it will be polled */
5785 break;
5786 case CHAN_X11:
5787 x11_unthrottle(c->u.x11.s);
5788 break;
5789 case CHAN_AGENT:
5790 /* agent sockets are request/response and need no
5791 * buffer management */
5792 break;
5793 case CHAN_SOCKDATA:
5794 pfd_unthrottle(c->u.pfd.s);
5795 break;
5796 }
5797 }
5798 }
7cca0d81 5799 }
e5574168 5800 }
5801
5802 crFinishV;
5803}
5804
5805/*
7cca0d81 5806 * Handle the top-level SSH2 protocol.
5807 */
51470298 5808static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
7cca0d81 5809{
51470298 5810 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
32874aea 5811 return;
51470298 5812 do_ssh2_authconn(ssh, in, inlen, ispkt);
7cca0d81 5813}
5814
5815/*
8df7a775 5816 * Called to set up the connection.
374330e2 5817 *
5818 * Returns an error message, or NULL on success.
374330e2 5819 */
51470298 5820static char *ssh_init(void *frontend_handle, void **backend_handle,
887035a5 5821 char *host, int port, char **realhost, int nodelay)
32874aea 5822{
fb09bf1c 5823 char *p;
51470298 5824 Ssh ssh;
5825
5826 ssh = smalloc(sizeof(*ssh));
5827 ssh->s = NULL;
5828 ssh->cipher = NULL;
371e569c 5829 ssh->v1_cipher_ctx = NULL;
0183b242 5830 ssh->crcda_ctx = NULL;
51470298 5831 ssh->cscipher = NULL;
371e569c 5832 ssh->cs_cipher_ctx = NULL;
51470298 5833 ssh->sccipher = NULL;
371e569c 5834 ssh->sc_cipher_ctx = NULL;
51470298 5835 ssh->csmac = NULL;
a8327734 5836 ssh->cs_mac_ctx = NULL;
51470298 5837 ssh->scmac = NULL;
e0e1a00d 5838 ssh->sc_mac_ctx = NULL;
51470298 5839 ssh->cscomp = NULL;
5366aed8 5840 ssh->cs_comp_ctx = NULL;
51470298 5841 ssh->sccomp = NULL;
5366aed8 5842 ssh->sc_comp_ctx = NULL;
51470298 5843 ssh->kex = NULL;
5844 ssh->hostkey = NULL;
5845 ssh->exitcode = -1;
5846 ssh->state = SSH_STATE_PREPACKET;
5847 ssh->size_needed = FALSE;
5848 ssh->eof_needed = FALSE;
b9d7bcad 5849 ssh->ldisc = NULL;
a8327734 5850 ssh->logctx = NULL;
51470298 5851 {
5852 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
5853 ssh->pktin = ssh->pktout = empty;
5854 }
5855 ssh->deferred_send_data = NULL;
5856 ssh->deferred_len = 0;
5857 ssh->deferred_size = 0;
5858 ssh->fallback_cmd = 0;
5859 ssh->pkt_ctx = 0;
302121de 5860 ssh->x11auth = NULL;
be738459 5861 ssh->v1_compressing = FALSE;
51470298 5862 ssh->v2_outgoing_sequence = 0;
5863 ssh->ssh1_rdpkt_crstate = 0;
5864 ssh->ssh2_rdpkt_crstate = 0;
5865 ssh->do_ssh_init_crstate = 0;
5866 ssh->ssh_gotdata_crstate = 0;
5867 ssh->ssh1_protocol_crstate = 0;
5868 ssh->do_ssh1_login_crstate = 0;
5869 ssh->do_ssh2_transport_crstate = 0;
5870 ssh->do_ssh2_authconn_crstate = 0;
5871 ssh->do_ssh_init_state = NULL;
5872 ssh->do_ssh1_login_state = NULL;
5873 ssh->do_ssh2_transport_state = NULL;
5874 ssh->do_ssh2_authconn_state = NULL;
6571dbfd 5875 ssh->mainchan = NULL;
968d2d92 5876 ssh->throttled_all = 0;
5877 ssh->v1_stdout_throttling = 0;
51470298 5878
5879 *backend_handle = ssh;
32874aea 5880
8f203108 5881#ifdef MSCRYPTOAPI
32874aea 5882 if (crypto_startup() == 0)
8f203108 5883 return "Microsoft high encryption pack not installed!";
5884#endif
374330e2 5885
51470298 5886 ssh->frontend = frontend_handle;
5887 ssh->term_width = cfg.width;
5888 ssh->term_height = cfg.height;
887035a5 5889
51470298 5890 ssh->send_ok = 0;
5891 ssh->editing = 0;
5892 ssh->echoing = 0;
5893 ssh->v1_throttle_count = 0;
5894 ssh->overall_bufsize = 0;
5895 ssh->fallback_cmd = 0;
8df7a775 5896
51470298 5897 p = connect_to_host(ssh, host, port, realhost, nodelay);
fb09bf1c 5898 if (p != NULL)
5899 return p;
374330e2 5900
374330e2 5901 return NULL;
5902}
5903
5904/*
374330e2 5905 * Called to send data down the Telnet connection.
5906 */
51470298 5907static int ssh_send(void *handle, char *buf, int len)
32874aea 5908{
51470298 5909 Ssh ssh = (Ssh) handle;
5910
5911 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5471d09a 5912 return 0;
374330e2 5913
51470298 5914 ssh->protocol(ssh, buf, len, 0);
5471d09a 5915
51470298 5916 return ssh_sendbuffer(ssh);
5471d09a 5917}
5918
5919/*
5920 * Called to query the current amount of buffered stdin data.
5921 */
51470298 5922static int ssh_sendbuffer(void *handle)
5471d09a 5923{
51470298 5924 Ssh ssh = (Ssh) handle;
5471d09a 5925 int override_value;
5926
51470298 5927 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5471d09a 5928 return 0;
5929
5930 /*
5931 * If the SSH socket itself has backed up, add the total backup
5932 * size on that to any individual buffer on the stdin channel.
5933 */
5934 override_value = 0;
51470298 5935 if (ssh->throttled_all)
5936 override_value = ssh->overall_bufsize;
5471d09a 5937
51470298 5938 if (ssh->version == 1) {
5471d09a 5939 return override_value;
51470298 5940 } else if (ssh->version == 2) {
5941 if (!ssh->mainchan || ssh->mainchan->closes > 0)
5471d09a 5942 return override_value;
5943 else
51470298 5944 return (override_value +
5945 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
5471d09a 5946 }
5947
5948 return 0;
374330e2 5949}
5950
5951/*
6e48c3fe 5952 * Called to set the size of the window from SSH's POV.
374330e2 5953 */
51470298 5954static void ssh_size(void *handle, int width, int height)
32874aea 5955{
51470298 5956 Ssh ssh = (Ssh) handle;
5957
5958 ssh->term_width = width;
5959 ssh->term_height = height;
f278d6f8 5960
51470298 5961 switch (ssh->state) {
374330e2 5962 case SSH_STATE_BEFORE_SIZE:
3687d221 5963 case SSH_STATE_PREPACKET:
21248260 5964 case SSH_STATE_CLOSED:
374330e2 5965 break; /* do nothing */
5966 case SSH_STATE_INTERMED:
51470298 5967 ssh->size_needed = TRUE; /* buffer for later */
374330e2 5968 break;
5969 case SSH_STATE_SESSION:
32874aea 5970 if (!cfg.nopty) {
51470298 5971 if (ssh->version == 1) {
5972 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
5973 PKT_INT, ssh->term_height,
5974 PKT_INT, ssh->term_width,
32874aea 5975 PKT_INT, 0, PKT_INT, 0, PKT_END);
5976 } else {
51470298 5977 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5978 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5979 ssh2_pkt_addstring(ssh, "window-change");
5980 ssh2_pkt_addbool(ssh, 0);
5981 ssh2_pkt_adduint32(ssh, ssh->term_width);
5982 ssh2_pkt_adduint32(ssh, ssh->term_height);
5983 ssh2_pkt_adduint32(ssh, 0);
5984 ssh2_pkt_adduint32(ssh, 0);
5985 ssh2_pkt_send(ssh);
32874aea 5986 }
5987 }
5988 break;
374330e2 5989 }
5990}
5991
5992/*
6abbf9e3 5993 * Send Telnet special codes. TS_EOF is useful for `plink', so you
5994 * can send an EOF and collect resulting output (e.g. `plink
5995 * hostname sort').
374330e2 5996 */
51470298 5997static void ssh_special(void *handle, Telnet_Special code)
32874aea 5998{
51470298 5999 Ssh ssh = (Ssh) handle;
6000
6abbf9e3 6001 if (code == TS_EOF) {
51470298 6002 if (ssh->state != SSH_STATE_SESSION) {
32874aea 6003 /*
6004 * Buffer the EOF in case we are pre-SESSION, so we can
6005 * send it as soon as we reach SESSION.
6006 */
6007 if (code == TS_EOF)
51470298 6008 ssh->eof_needed = TRUE;
32874aea 6009 return;
6010 }
51470298 6011 if (ssh->version == 1) {
6012 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
32874aea 6013 } else {
51470298 6014 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6015 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6016 ssh2_pkt_send(ssh);
32874aea 6017 }
6018 logevent("Sent EOF message");
ec55b220 6019 } else if (code == TS_PING) {
51470298 6020 if (ssh->state == SSH_STATE_CLOSED
6021 || ssh->state == SSH_STATE_PREPACKET) return;
6022 if (ssh->version == 1) {
6023 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6024 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
32874aea 6025 } else {
51470298 6026 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6027 ssh2_pkt_addstring_start(ssh);
6028 ssh2_pkt_send(ssh);
32874aea 6029 }
6abbf9e3 6030 } else {
32874aea 6031 /* do nothing */
6abbf9e3 6032 }
374330e2 6033}
6034
51470298 6035void *new_sock_channel(void *handle, Socket s)
d74d141c 6036{
51470298 6037 Ssh ssh = (Ssh) handle;
d74d141c 6038 struct ssh_channel *c;
6039 c = smalloc(sizeof(struct ssh_channel));
51470298 6040 c->ssh = ssh;
d74d141c 6041
6042 if (c) {
bc240b21 6043 c->remoteid = -1; /* to be set when open confirmed */
51470298 6044 c->localid = alloc_channel_id(ssh);
d74d141c 6045 c->closes = 0;
bc240b21 6046 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
d74d141c 6047 c->u.pfd.s = s;
013dd8c0 6048 bufchain_init(&c->v.v2.outbuffer);
51470298 6049 add234(ssh->channels, c);
d74d141c 6050 }
6051 return c;
6052}
6053
5471d09a 6054/*
6055 * This is called when stdout/stderr (the entity to which
6056 * from_backend sends data) manages to clear some backlog.
6057 */
51470298 6058void ssh_unthrottle(void *handle, int bufsize)
5471d09a 6059{
51470298 6060 Ssh ssh = (Ssh) handle;
6061 if (ssh->version == 1) {
6062 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6063 ssh->v1_stdout_throttling = 0;
6064 ssh1_throttle(ssh, -1);
5471d09a 6065 }
6066 } else {
51470298 6067 if (ssh->mainchan && ssh->mainchan->closes == 0)
6068 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
5471d09a 6069 }
6070}
6071
6b78788a 6072void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
d74d141c 6073{
6074 struct ssh_channel *c = (struct ssh_channel *)channel;
6b78788a 6075 Ssh ssh = c->ssh;
d74d141c 6076
57356d63 6077 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
d74d141c 6078
51470298 6079 if (ssh->version == 1) {
6080 send_packet(ssh, SSH1_MSG_PORT_OPEN,
bc240b21 6081 PKT_INT, c->localid,
6082 PKT_STR, hostname,
6083 PKT_INT, port,
6084 //PKT_STR, <org:orgport>,
6085 PKT_END);
6086 } else {
51470298 6087 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6088 ssh2_pkt_addstring(ssh, "direct-tcpip");
6089 ssh2_pkt_adduint32(ssh, c->localid);
5471d09a 6090 c->v.v2.locwindow = OUR_V2_WINSIZE;
51470298 6091 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6092 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6093 ssh2_pkt_addstring(ssh, hostname);
6094 ssh2_pkt_adduint32(ssh, port);
bc240b21 6095 /*
6096 * We make up values for the originator data; partly it's
6097 * too much hassle to keep track, and partly I'm not
6098 * convinced the server should be told details like that
6099 * about my local network configuration.
6100 */
51470298 6101 ssh2_pkt_addstring(ssh, "client-side-connection");
6102 ssh2_pkt_adduint32(ssh, 0);
6103 ssh2_pkt_send(ssh);
bc240b21 6104 }
d74d141c 6105}
6106
6107
51470298 6108static Socket ssh_socket(void *handle)
32874aea 6109{
51470298 6110 Ssh ssh = (Ssh) handle;
6111 return ssh->s;
32874aea 6112}
8ccc75b0 6113
51470298 6114static int ssh_sendok(void *handle)
32874aea 6115{
51470298 6116 Ssh ssh = (Ssh) handle;
6117 return ssh->send_ok;
32874aea 6118}
fb09bf1c 6119
51470298 6120static int ssh_ldisc(void *handle, int option)
32874aea 6121{
51470298 6122 Ssh ssh = (Ssh) handle;
32874aea 6123 if (option == LD_ECHO)
51470298 6124 return ssh->echoing;
32874aea 6125 if (option == LD_EDIT)
51470298 6126 return ssh->editing;
0965bee0 6127 return FALSE;
6128}
6129
b9d7bcad 6130static void ssh_provide_ldisc(void *handle, void *ldisc)
6131{
6132 Ssh ssh = (Ssh) handle;
6133 ssh->ldisc = ldisc;
6134}
6135
a8327734 6136static void ssh_provide_logctx(void *handle, void *logctx)
6137{
6138 Ssh ssh = (Ssh) handle;
6139 ssh->logctx = logctx;
6140}
6141
51470298 6142static int ssh_return_exitcode(void *handle)
6143{
6144 Ssh ssh = (Ssh) handle;
6145 return ssh->exitcode;
6146}
6147
6148/*
6149 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6150 * that fails. This variable is the means by which scp.c can reach
6151 * into the SSH code and find out which one it got.
6152 */
6153extern int ssh_fallback_cmd(void *handle)
d8d6c7e5 6154{
51470298 6155 Ssh ssh = (Ssh) handle;
6156 return ssh->fallback_cmd;
d8d6c7e5 6157}
6158
374330e2 6159Backend ssh_backend = {
6160 ssh_init,
374330e2 6161 ssh_send,
5471d09a 6162 ssh_sendbuffer,
374330e2 6163 ssh_size,
4017be6d 6164 ssh_special,
8ccc75b0 6165 ssh_socket,
d8d6c7e5 6166 ssh_return_exitcode,
97db3be4 6167 ssh_sendok,
0965bee0 6168 ssh_ldisc,
b9d7bcad 6169 ssh_provide_ldisc,
a8327734 6170 ssh_provide_logctx,
5471d09a 6171 ssh_unthrottle,
97db3be4 6172 22
bc240b21 6173};
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator