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First draft of Unicode support in pterm. It's pretty complete: it
[u/mdw/putty] / ssh.c
1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <stdarg.h>
4 #include <assert.h>
5
6 #include "putty.h"
7 #include "tree234.h"
8 #include "ssh.h"
9
10 #ifndef FALSE
11 #define FALSE 0
12 #endif
13 #ifndef TRUE
14 #define TRUE 1
15 #endif
16
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 */
63 /* Mask for protoflags we will echo back to server if seen */
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 */
86 #define SSH2_MSG_USERAUTH_INFO_REQUEST 60 /* 0x3c */
87 #define SSH2_MSG_USERAUTH_INFO_RESPONSE 61 /* 0x3d */
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
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
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 */
129
130 static 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 };
148
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 */
153
154 #define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
155
156 /*
157 * Various remote-bug flags.
158 */
159 #define BUG_CHOKES_ON_SSH1_IGNORE 1
160 #define BUG_SSH2_HMAC 2
161 #define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
162 #define BUG_CHOKES_ON_RSA 8
163 #define BUG_SSH2_RSA_PADDING 16
164 #define BUG_SSH2_DERIVEKEY 32
165 #define BUG_SSH2_DH_GEX 64
166
167 #define translate(x) if (type == x) return #x
168 #define translatec(x,ctx) if (type == x && (pkt_ctx & ctx)) return #x
169 char *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 }
214 char *ssh2_pkt_type(int pkt_ctx, int type)
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
256
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
269 enum { PKT_END, PKT_INT, PKT_CHAR, PKT_DATA, PKT_STR, PKT_BIGNUM };
270
271 /* Coroutine mechanics for the sillier bits of the code */
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; }
279 #define crReturn(z) \
280 do {\
281 *crLine =__LINE__; return (z); case __LINE__:;\
282 } while (0)
283 #define crReturnV \
284 do {\
285 *crLine=__LINE__; return; case __LINE__:;\
286 } while (0)
287 #define crStop(z) do{ *crLine = 0; return (z); }while(0)
288 #define crStopV do{ *crLine = 0; return; }while(0)
289 #define crWaitUntil(c) do { crReturn(0); } while (!(c))
290 #define crWaitUntilV(c) do { crReturnV; } while (!(c))
291
292 typedef struct ssh_tag *Ssh;
293
294 extern char *x11_init(Socket *, char *, void *, void *);
295 extern void x11_close(Socket);
296 extern int x11_send(Socket, char *, int);
297 extern void *x11_invent_auth(char *, int, char *, int);
298 extern void x11_unthrottle(Socket s);
299 extern void x11_override_throttle(Socket s, int enable);
300
301 extern char *pfd_newconnect(Socket * s, char *hostname, int port, void *c);
302 extern char *pfd_addforward(char *desthost, int destport, char *srcaddr,
303 int port, void *backhandle);
304 extern void pfd_close(Socket s);
305 extern int pfd_send(Socket s, char *data, int len);
306 extern void pfd_confirm(Socket s);
307 extern void pfd_unthrottle(Socket s);
308 extern void pfd_override_throttle(Socket s, int enable);
309
310 static void ssh2_pkt_init(Ssh, int pkt_type);
311 static void ssh2_pkt_addbool(Ssh, unsigned char value);
312 static void ssh2_pkt_adduint32(Ssh, unsigned long value);
313 static void ssh2_pkt_addstring_start(Ssh);
314 static void ssh2_pkt_addstring_str(Ssh, char *data);
315 static void ssh2_pkt_addstring_data(Ssh, char *data, int len);
316 static void ssh2_pkt_addstring(Ssh, char *data);
317 static char *ssh2_mpint_fmt(Bignum b, int *len);
318 static void ssh2_pkt_addmp(Ssh, Bignum b);
319 static int ssh2_pkt_construct(Ssh);
320 static void ssh2_pkt_send(Ssh);
321
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
346
347 const static struct ssh_kex *kex_algs[] = {
348 &ssh_diffiehellman_gex,
349 &ssh_diffiehellman
350 };
351
352 const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
353
354 static void *nullmac_make_context(void)
355 {
356 return NULL;
357 }
358 static void nullmac_free_context(void *handle)
359 {
360 }
361 static void nullmac_key(void *handle, unsigned char *key)
362 {
363 }
364 static void nullmac_generate(void *handle, unsigned char *blk, int len,
365 unsigned long seq)
366 {
367 }
368 static int nullmac_verify(void *handle, unsigned char *blk, int len,
369 unsigned long seq)
370 {
371 return 1;
372 }
373 const static struct ssh_mac ssh_mac_none = {
374 nullmac_make_context, nullmac_free_context, nullmac_key,
375 nullmac_generate, nullmac_verify, "none", 0
376 };
377 const static struct ssh_mac *macs[] = {
378 &ssh_sha1, &ssh_md5, &ssh_mac_none
379 };
380 const static struct ssh_mac *buggymacs[] = {
381 &ssh_sha1_buggy, &ssh_md5, &ssh_mac_none
382 };
383
384 static void *ssh_comp_none_init(void)
385 {
386 return NULL;
387 }
388 static void ssh_comp_none_cleanup(void *handle)
389 {
390 }
391 static int ssh_comp_none_block(void *handle, unsigned char *block, int len,
392 unsigned char **outblock, int *outlen)
393 {
394 return 0;
395 }
396 static int ssh_comp_none_disable(void *handle)
397 {
398 return 0;
399 }
400 const static struct ssh_compress ssh_comp_none = {
401 "none",
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
405 };
406 extern const struct ssh_compress ssh_zlib;
407 const static struct ssh_compress *compressions[] = {
408 &ssh_zlib, &ssh_comp_none
409 };
410
411 enum { /* channel types */
412 CHAN_MAINSESSION,
413 CHAN_X11,
414 CHAN_AGENT,
415 CHAN_SOCKDATA,
416 CHAN_SOCKDATA_DORMANT /* one the remote hasn't confirmed */
417 };
418
419 /*
420 * 2-3-4 tree storing channels.
421 */
422 struct ssh_channel {
423 Ssh ssh; /* pointer back to main context */
424 unsigned remoteid, localid;
425 int type;
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 */
436 int closes;
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;
447 union {
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;
456 struct ssh_pfd_channel {
457 Socket s;
458 } pfd;
459 } u;
460 };
461
462 /*
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.
490 */
491 struct ssh_rportfwd {
492 unsigned sport, dport;
493 char dhost[256];
494 };
495
496 struct Packet {
497 long length;
498 int type;
499 unsigned char *data;
500 unsigned char *body;
501 long savedpos;
502 long maxlen;
503 };
504
505 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
506 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt);
507 static void ssh_size(void *handle, int width, int height);
508 static void ssh_special(void *handle, Telnet_Special);
509 static int ssh2_try_send(struct ssh_channel *c);
510 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf, int len);
511 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize);
512 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin);
513 static int ssh_sendbuffer(void *handle);
514
515 struct rdpkt1_state_tag {
516 long len, pad, biglen, to_read;
517 unsigned long realcrc, gotcrc;
518 unsigned char *p;
519 int i;
520 int chunk;
521 };
522
523 struct rdpkt2_state_tag {
524 long len, pad, payload, packetlen, maclen;
525 int i;
526 int cipherblk;
527 unsigned long incoming_sequence;
528 };
529
530 struct 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
538 void *ldisc;
539 void *logctx;
540
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;
549 void *v1_cipher_ctx;
550 void *crcda_ctx;
551 const struct ssh2_cipher *cscipher, *sccipher;
552 void *cs_cipher_ctx, *sc_cipher_ctx;
553 const struct ssh_mac *csmac, *scmac;
554 void *cs_mac_ctx, *sc_mac_ctx;
555 const struct ssh_compress *cscomp, *sccomp;
556 void *cs_comp_ctx, *sc_comp_ctx;
557 const struct ssh_kex *kex;
558 const struct ssh_signkey *hostkey;
559 unsigned char v2_session_id[20];
560 void *kex_ctx;
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
611 void *x11auth;
612
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 };
640
641 #define logevent(s) logevent(ssh->frontend, s)
642
643 /* logevent, only printf-formatted. */
644 void logeventf(Ssh ssh, char *fmt, ...)
645 {
646 va_list ap;
647 char *buf;
648
649 va_start(ap, fmt);
650 buf = dupvprintf(fmt, ap);
651 va_end(ap);
652 logevent(buf);
653 sfree(buf);
654 }
655
656 #define bombout(msg) ( ssh->state = SSH_STATE_CLOSED, \
657 (ssh->s ? sk_close(ssh->s), ssh->s = NULL : 0), \
658 logeventf msg, connection_fatal msg )
659
660 static int ssh_channelcmp(void *av, void *bv)
661 {
662 struct ssh_channel *a = (struct ssh_channel *) av;
663 struct ssh_channel *b = (struct ssh_channel *) bv;
664 if (a->localid < b->localid)
665 return -1;
666 if (a->localid > b->localid)
667 return +1;
668 return 0;
669 }
670 static int ssh_channelfind(void *av, void *bv)
671 {
672 unsigned *a = (unsigned *) av;
673 struct ssh_channel *b = (struct ssh_channel *) bv;
674 if (*a < b->localid)
675 return -1;
676 if (*a > b->localid)
677 return +1;
678 return 0;
679 }
680
681 static int ssh_rportcmp_ssh1(void *av, void *bv)
682 {
683 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
684 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
685 int i;
686 if ( (i = strcmp(a->dhost, b->dhost)) != 0)
687 return i < 0 ? -1 : +1;
688 if (a->dport > b->dport)
689 return +1;
690 if (a->dport < b->dport)
691 return -1;
692 return 0;
693 }
694
695 static int ssh_rportcmp_ssh2(void *av, void *bv)
696 {
697 struct ssh_rportfwd *a = (struct ssh_rportfwd *) av;
698 struct ssh_rportfwd *b = (struct ssh_rportfwd *) bv;
699
700 if (a->sport > b->sport)
701 return +1;
702 if (a->sport < b->sport)
703 return -1;
704 return 0;
705 }
706
707 static int alloc_channel_id(Ssh ssh)
708 {
709 const unsigned CHANNEL_NUMBER_OFFSET = 256;
710 unsigned low, high, mid;
711 int tsize;
712 struct ssh_channel *c;
713
714 /*
715 * First-fit allocation of channel numbers: always pick the
716 * lowest unused one. To do this, binary-search using the
717 * counted B-tree to find the largest channel ID which is in a
718 * contiguous sequence from the beginning. (Precisely
719 * everything in that sequence must have ID equal to its tree
720 * index plus CHANNEL_NUMBER_OFFSET.)
721 */
722 tsize = count234(ssh->channels);
723
724 low = -1;
725 high = tsize;
726 while (high - low > 1) {
727 mid = (high + low) / 2;
728 c = index234(ssh->channels, mid);
729 if (c->localid == mid + CHANNEL_NUMBER_OFFSET)
730 low = mid; /* this one is fine */
731 else
732 high = mid; /* this one is past it */
733 }
734 /*
735 * Now low points to either -1, or the tree index of the
736 * largest ID in the initial sequence.
737 */
738 {
739 unsigned i = low + 1 + CHANNEL_NUMBER_OFFSET;
740 assert(NULL == find234(ssh->channels, &i, ssh_channelfind));
741 }
742 return low + 1 + CHANNEL_NUMBER_OFFSET;
743 }
744
745 static void c_write(Ssh ssh, char *buf, int len)
746 {
747 if ((flags & FLAG_STDERR)) {
748 int i;
749 for (i = 0; i < len; i++)
750 if (buf[i] != '\r')
751 fputc(buf[i], stderr);
752 return;
753 }
754 from_backend(ssh->frontend, 1, buf, len);
755 }
756
757 static void c_write_untrusted(Ssh ssh, char *buf, int len)
758 {
759 int i;
760 for (i = 0; i < len; i++) {
761 if (buf[i] == '\n')
762 c_write(ssh, "\r\n", 2);
763 else if ((buf[i] & 0x60) || (buf[i] == '\r'))
764 c_write(ssh, buf + i, 1);
765 }
766 }
767
768 static void c_write_str(Ssh ssh, char *buf)
769 {
770 c_write(ssh, buf, strlen(buf));
771 }
772
773 /*
774 * Collect incoming data in the incoming packet buffer.
775 * Decipher and verify the packet when it is completely read.
776 * Drop SSH1_MSG_DEBUG and SSH1_MSG_IGNORE packets.
777 * Update the *data and *datalen variables.
778 * Return the additional nr of bytes needed, or 0 when
779 * a complete packet is available.
780 */
781 static int ssh1_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
782 {
783 struct rdpkt1_state_tag *st = &ssh->rdpkt1_state;
784
785 crBegin(ssh->ssh1_rdpkt_crstate);
786
787 next_packet:
788
789 ssh->pktin.type = 0;
790 ssh->pktin.length = 0;
791
792 for (st->i = st->len = 0; st->i < 4; st->i++) {
793 while ((*datalen) == 0)
794 crReturn(4 - st->i);
795 st->len = (st->len << 8) + **data;
796 (*data)++, (*datalen)--;
797 }
798
799 st->pad = 8 - (st->len % 8);
800 st->biglen = st->len + st->pad;
801 ssh->pktin.length = st->len - 5;
802
803 if (ssh->pktin.maxlen < st->biglen) {
804 ssh->pktin.maxlen = st->biglen;
805 ssh->pktin.data = srealloc(ssh->pktin.data, st->biglen + APIEXTRA);
806 }
807
808 st->to_read = st->biglen;
809 st->p = ssh->pktin.data;
810 while (st->to_read > 0) {
811 st->chunk = st->to_read;
812 while ((*datalen) == 0)
813 crReturn(st->to_read);
814 if (st->chunk > (*datalen))
815 st->chunk = (*datalen);
816 memcpy(st->p, *data, st->chunk);
817 *data += st->chunk;
818 *datalen -= st->chunk;
819 st->p += st->chunk;
820 st->to_read -= st->chunk;
821 }
822
823 if (ssh->cipher && detect_attack(ssh->crcda_ctx, ssh->pktin.data,
824 st->biglen, NULL)) {
825 bombout((ssh,"Network attack (CRC compensation) detected!"));
826 crReturn(0);
827 }
828
829 if (ssh->cipher)
830 ssh->cipher->decrypt(ssh->v1_cipher_ctx, ssh->pktin.data, st->biglen);
831
832 st->realcrc = crc32(ssh->pktin.data, st->biglen - 4);
833 st->gotcrc = GET_32BIT(ssh->pktin.data + st->biglen - 4);
834 if (st->gotcrc != st->realcrc) {
835 bombout((ssh,"Incorrect CRC received on packet"));
836 crReturn(0);
837 }
838
839 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
840
841 if (ssh->v1_compressing) {
842 unsigned char *decompblk;
843 int decomplen;
844 zlib_decompress_block(ssh->sc_comp_ctx,
845 ssh->pktin.body - 1, ssh->pktin.length + 1,
846 &decompblk, &decomplen);
847
848 if (ssh->pktin.maxlen < st->pad + decomplen) {
849 ssh->pktin.maxlen = st->pad + decomplen;
850 ssh->pktin.data = srealloc(ssh->pktin.data,
851 ssh->pktin.maxlen + APIEXTRA);
852 ssh->pktin.body = ssh->pktin.data + st->pad + 1;
853 }
854
855 memcpy(ssh->pktin.body - 1, decompblk, decomplen);
856 sfree(decompblk);
857 ssh->pktin.length = decomplen - 1;
858 }
859
860 ssh->pktin.type = ssh->pktin.body[-1];
861
862 if (ssh->logctx)
863 log_packet(ssh->logctx,
864 PKT_INCOMING, ssh->pktin.type,
865 ssh1_pkt_type(ssh->pktin.type),
866 ssh->pktin.body, ssh->pktin.length);
867
868 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
869 ssh->pktin.type == SSH1_SMSG_STDERR_DATA ||
870 ssh->pktin.type == SSH1_MSG_DEBUG ||
871 ssh->pktin.type == SSH1_SMSG_AUTH_TIS_CHALLENGE ||
872 ssh->pktin.type == SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
873 long stringlen = GET_32BIT(ssh->pktin.body);
874 if (stringlen + 4 != ssh->pktin.length) {
875 bombout((ssh,"Received data packet with bogus string length"));
876 crReturn(0);
877 }
878 }
879
880 if (ssh->pktin.type == SSH1_MSG_DEBUG) {
881 /* log debug message */
882 char buf[512];
883 int stringlen = GET_32BIT(ssh->pktin.body);
884 strcpy(buf, "Remote debug message: ");
885 if (stringlen > 480)
886 stringlen = 480;
887 memcpy(buf + 8, ssh->pktin.body + 4, stringlen);
888 buf[8 + stringlen] = '\0';
889 logevent(buf);
890 goto next_packet;
891 } else if (ssh->pktin.type == SSH1_MSG_IGNORE) {
892 /* do nothing */
893 goto next_packet;
894 }
895
896 if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
897 /* log reason code in disconnect message */
898 char buf[256];
899 unsigned msglen = GET_32BIT(ssh->pktin.body);
900 unsigned nowlen;
901 strcpy(buf, "Remote sent disconnect: ");
902 nowlen = strlen(buf);
903 if (msglen > sizeof(buf) - nowlen - 1)
904 msglen = sizeof(buf) - nowlen - 1;
905 memcpy(buf + nowlen, ssh->pktin.body + 4, msglen);
906 buf[nowlen + msglen] = '\0';
907 /* logevent(buf); (this is now done within the bombout macro) */
908 bombout((ssh,"Server sent disconnect message:\n\"%s\"", buf+nowlen));
909 crReturn(0);
910 }
911
912 crFinish(0);
913 }
914
915 static int ssh2_rdpkt(Ssh ssh, unsigned char **data, int *datalen)
916 {
917 struct rdpkt2_state_tag *st = &ssh->rdpkt2_state;
918
919 crBegin(ssh->ssh2_rdpkt_crstate);
920
921 next_packet:
922 ssh->pktin.type = 0;
923 ssh->pktin.length = 0;
924 if (ssh->sccipher)
925 st->cipherblk = ssh->sccipher->blksize;
926 else
927 st->cipherblk = 8;
928 if (st->cipherblk < 8)
929 st->cipherblk = 8;
930
931 if (ssh->pktin.maxlen < st->cipherblk) {
932 ssh->pktin.maxlen = st->cipherblk;
933 ssh->pktin.data = srealloc(ssh->pktin.data, st->cipherblk + APIEXTRA);
934 }
935
936 /*
937 * Acquire and decrypt the first block of the packet. This will
938 * contain the length and padding details.
939 */
940 for (st->i = st->len = 0; st->i < st->cipherblk; st->i++) {
941 while ((*datalen) == 0)
942 crReturn(st->cipherblk - st->i);
943 ssh->pktin.data[st->i] = *(*data)++;
944 (*datalen)--;
945 }
946
947 if (ssh->sccipher)
948 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
949 ssh->pktin.data, st->cipherblk);
950
951 /*
952 * Now get the length and padding figures.
953 */
954 st->len = GET_32BIT(ssh->pktin.data);
955 st->pad = ssh->pktin.data[4];
956
957 /*
958 * _Completely_ silly lengths should be stomped on before they
959 * do us any more damage.
960 */
961 if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
962 bombout((ssh,"Incoming packet was garbled on decryption"));
963 crReturn(0);
964 }
965
966 /*
967 * This enables us to deduce the payload length.
968 */
969 st->payload = st->len - st->pad - 1;
970
971 ssh->pktin.length = st->payload + 5;
972
973 /*
974 * So now we can work out the total packet length.
975 */
976 st->packetlen = st->len + 4;
977 st->maclen = ssh->scmac ? ssh->scmac->len : 0;
978
979 /*
980 * Adjust memory allocation if packet is too big.
981 */
982 if (ssh->pktin.maxlen < st->packetlen + st->maclen) {
983 ssh->pktin.maxlen = st->packetlen + st->maclen;
984 ssh->pktin.data = srealloc(ssh->pktin.data,
985 ssh->pktin.maxlen + APIEXTRA);
986 }
987
988 /*
989 * Read and decrypt the remainder of the packet.
990 */
991 for (st->i = st->cipherblk; st->i < st->packetlen + st->maclen;
992 st->i++) {
993 while ((*datalen) == 0)
994 crReturn(st->packetlen + st->maclen - st->i);
995 ssh->pktin.data[st->i] = *(*data)++;
996 (*datalen)--;
997 }
998 /* Decrypt everything _except_ the MAC. */
999 if (ssh->sccipher)
1000 ssh->sccipher->decrypt(ssh->sc_cipher_ctx,
1001 ssh->pktin.data + st->cipherblk,
1002 st->packetlen - st->cipherblk);
1003
1004 /*
1005 * Check the MAC.
1006 */
1007 if (ssh->scmac
1008 && !ssh->scmac->verify(ssh->sc_mac_ctx, ssh->pktin.data, st->len + 4,
1009 st->incoming_sequence)) {
1010 bombout((ssh,"Incorrect MAC received on packet"));
1011 crReturn(0);
1012 }
1013 st->incoming_sequence++; /* whether or not we MACed */
1014
1015 /*
1016 * Decompress packet payload.
1017 */
1018 {
1019 unsigned char *newpayload;
1020 int newlen;
1021 if (ssh->sccomp &&
1022 ssh->sccomp->decompress(ssh->sc_comp_ctx,
1023 ssh->pktin.data + 5, ssh->pktin.length - 5,
1024 &newpayload, &newlen)) {
1025 if (ssh->pktin.maxlen < newlen + 5) {
1026 ssh->pktin.maxlen = newlen + 5;
1027 ssh->pktin.data = srealloc(ssh->pktin.data,
1028 ssh->pktin.maxlen + APIEXTRA);
1029 }
1030 ssh->pktin.length = 5 + newlen;
1031 memcpy(ssh->pktin.data + 5, newpayload, newlen);
1032 sfree(newpayload);
1033 }
1034 }
1035
1036 ssh->pktin.savedpos = 6;
1037 ssh->pktin.type = ssh->pktin.data[5];
1038
1039 if (ssh->logctx)
1040 log_packet(ssh->logctx, PKT_INCOMING, ssh->pktin.type,
1041 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktin.type),
1042 ssh->pktin.data+6, ssh->pktin.length-6);
1043
1044 switch (ssh->pktin.type) {
1045 /*
1046 * These packets we must handle instantly.
1047 */
1048 case SSH2_MSG_DISCONNECT:
1049 {
1050 /* log reason code in disconnect message */
1051 char *buf;
1052 int nowlen;
1053 int reason = GET_32BIT(ssh->pktin.data + 6);
1054 unsigned msglen = GET_32BIT(ssh->pktin.data + 10);
1055
1056 if (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) {
1057 buf = dupprintf("Received disconnect message (%s)",
1058 ssh2_disconnect_reasons[reason]);
1059 } else {
1060 buf = dupprintf("Received disconnect message (unknown"
1061 " type %d)", reason);
1062 }
1063 logevent(buf);
1064 sfree(buf);
1065 buf = dupprintf("Disconnection message text: %n%.*s",
1066 &nowlen, msglen, ssh->pktin.data + 14);
1067 logevent(buf);
1068 bombout((ssh,"Server sent disconnect message\ntype %d (%s):\n\"%s\"",
1069 reason,
1070 (reason > 0 && reason < lenof(ssh2_disconnect_reasons)) ?
1071 ssh2_disconnect_reasons[reason] : "unknown",
1072 buf+nowlen));
1073 sfree(buf);
1074 crReturn(0);
1075 }
1076 break;
1077 case SSH2_MSG_IGNORE:
1078 goto next_packet;
1079 case SSH2_MSG_DEBUG:
1080 {
1081 /* log the debug message */
1082 char buf[512];
1083 /* int display = ssh->pktin.body[6]; */
1084 int stringlen = GET_32BIT(ssh->pktin.data+7);
1085 int prefix;
1086 strcpy(buf, "Remote debug message: ");
1087 prefix = strlen(buf);
1088 if (stringlen > (int)(sizeof(buf)-prefix-1))
1089 stringlen = sizeof(buf)-prefix-1;
1090 memcpy(buf + prefix, ssh->pktin.data + 11, stringlen);
1091 buf[prefix + stringlen] = '\0';
1092 logevent(buf);
1093 }
1094 goto next_packet; /* FIXME: print the debug message */
1095
1096 /*
1097 * These packets we need do nothing about here.
1098 */
1099 case SSH2_MSG_UNIMPLEMENTED:
1100 case SSH2_MSG_SERVICE_REQUEST:
1101 case SSH2_MSG_SERVICE_ACCEPT:
1102 case SSH2_MSG_KEXINIT:
1103 case SSH2_MSG_NEWKEYS:
1104 case SSH2_MSG_KEXDH_INIT:
1105 case SSH2_MSG_KEXDH_REPLY:
1106 /* case SSH2_MSG_KEX_DH_GEX_REQUEST: duplicate case value */
1107 /* case SSH2_MSG_KEX_DH_GEX_GROUP: duplicate case value */
1108 case SSH2_MSG_KEX_DH_GEX_INIT:
1109 case SSH2_MSG_KEX_DH_GEX_REPLY:
1110 case SSH2_MSG_USERAUTH_REQUEST:
1111 case SSH2_MSG_USERAUTH_FAILURE:
1112 case SSH2_MSG_USERAUTH_SUCCESS:
1113 case SSH2_MSG_USERAUTH_BANNER:
1114 case SSH2_MSG_USERAUTH_PK_OK:
1115 /* case SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ: duplicate case value */
1116 /* case SSH2_MSG_USERAUTH_INFO_REQUEST: duplicate case value */
1117 case SSH2_MSG_USERAUTH_INFO_RESPONSE:
1118 case SSH2_MSG_GLOBAL_REQUEST:
1119 case SSH2_MSG_REQUEST_SUCCESS:
1120 case SSH2_MSG_REQUEST_FAILURE:
1121 case SSH2_MSG_CHANNEL_OPEN:
1122 case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION:
1123 case SSH2_MSG_CHANNEL_OPEN_FAILURE:
1124 case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
1125 case SSH2_MSG_CHANNEL_DATA:
1126 case SSH2_MSG_CHANNEL_EXTENDED_DATA:
1127 case SSH2_MSG_CHANNEL_EOF:
1128 case SSH2_MSG_CHANNEL_CLOSE:
1129 case SSH2_MSG_CHANNEL_REQUEST:
1130 case SSH2_MSG_CHANNEL_SUCCESS:
1131 case SSH2_MSG_CHANNEL_FAILURE:
1132 break;
1133
1134 /*
1135 * For anything else we send SSH2_MSG_UNIMPLEMENTED.
1136 */
1137 default:
1138 ssh2_pkt_init(ssh, SSH2_MSG_UNIMPLEMENTED);
1139 ssh2_pkt_adduint32(ssh, st->incoming_sequence - 1);
1140 ssh2_pkt_send(ssh);
1141 break;
1142 }
1143
1144 crFinish(0);
1145 }
1146
1147 static void ssh1_pktout_size(Ssh ssh, int len)
1148 {
1149 int pad, biglen;
1150
1151 len += 5; /* type and CRC */
1152 pad = 8 - (len % 8);
1153 biglen = len + pad;
1154
1155 ssh->pktout.length = len - 5;
1156 if (ssh->pktout.maxlen < biglen) {
1157 ssh->pktout.maxlen = biglen;
1158 #ifdef MSCRYPTOAPI
1159 /* Allocate enough buffer space for extra block
1160 * for MS CryptEncrypt() */
1161 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 12);
1162 #else
1163 ssh->pktout.data = srealloc(ssh->pktout.data, biglen + 4);
1164 #endif
1165 }
1166 ssh->pktout.body = ssh->pktout.data + 4 + pad + 1;
1167 }
1168
1169 static void s_wrpkt_start(Ssh ssh, int type, int len)
1170 {
1171 ssh1_pktout_size(ssh, len);
1172 ssh->pktout.type = type;
1173 }
1174
1175 static int s_wrpkt_prepare(Ssh ssh)
1176 {
1177 int pad, len, biglen, i;
1178 unsigned long crc;
1179
1180 ssh->pktout.body[-1] = ssh->pktout.type;
1181
1182 if (ssh->logctx)
1183 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.type,
1184 ssh1_pkt_type(ssh->pktout.type),
1185 ssh->pktout.body, ssh->pktout.length);
1186
1187 if (ssh->v1_compressing) {
1188 unsigned char *compblk;
1189 int complen;
1190 zlib_compress_block(ssh->cs_comp_ctx,
1191 ssh->pktout.body - 1, ssh->pktout.length + 1,
1192 &compblk, &complen);
1193 ssh1_pktout_size(ssh, complen - 1);
1194 memcpy(ssh->pktout.body - 1, compblk, complen);
1195 sfree(compblk);
1196 }
1197
1198 len = ssh->pktout.length + 5; /* type and CRC */
1199 pad = 8 - (len % 8);
1200 biglen = len + pad;
1201
1202 for (i = 0; i < pad; i++)
1203 ssh->pktout.data[i + 4] = random_byte();
1204 crc = crc32(ssh->pktout.data + 4, biglen - 4);
1205 PUT_32BIT(ssh->pktout.data + biglen, crc);
1206 PUT_32BIT(ssh->pktout.data, len);
1207
1208 if (ssh->cipher)
1209 ssh->cipher->encrypt(ssh->v1_cipher_ctx, ssh->pktout.data + 4, biglen);
1210
1211 return biglen + 4;
1212 }
1213
1214 static void s_wrpkt(Ssh ssh)
1215 {
1216 int len, backlog;
1217 len = s_wrpkt_prepare(ssh);
1218 backlog = sk_write(ssh->s, ssh->pktout.data, len);
1219 if (backlog > SSH_MAX_BACKLOG)
1220 ssh_throttle_all(ssh, 1, backlog);
1221 }
1222
1223 static void s_wrpkt_defer(Ssh ssh)
1224 {
1225 int len;
1226 len = s_wrpkt_prepare(ssh);
1227 if (ssh->deferred_len + len > ssh->deferred_size) {
1228 ssh->deferred_size = ssh->deferred_len + len + 128;
1229 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1230 ssh->deferred_size);
1231 }
1232 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1233 ssh->deferred_len += len;
1234 }
1235
1236 /*
1237 * Construct a packet with the specified contents.
1238 */
1239 static void construct_packet(Ssh ssh, int pkttype, va_list ap1, va_list ap2)
1240 {
1241 unsigned char *p, *argp, argchar;
1242 unsigned long argint;
1243 int pktlen, argtype, arglen;
1244 Bignum bn;
1245
1246 pktlen = 0;
1247 while ((argtype = va_arg(ap1, int)) != PKT_END) {
1248 switch (argtype) {
1249 case PKT_INT:
1250 (void) va_arg(ap1, int);
1251 pktlen += 4;
1252 break;
1253 case PKT_CHAR:
1254 (void) va_arg(ap1, int);
1255 pktlen++;
1256 break;
1257 case PKT_DATA:
1258 (void) va_arg(ap1, unsigned char *);
1259 arglen = va_arg(ap1, int);
1260 pktlen += arglen;
1261 break;
1262 case PKT_STR:
1263 argp = va_arg(ap1, unsigned char *);
1264 arglen = strlen(argp);
1265 pktlen += 4 + arglen;
1266 break;
1267 case PKT_BIGNUM:
1268 bn = va_arg(ap1, Bignum);
1269 pktlen += ssh1_bignum_length(bn);
1270 break;
1271 default:
1272 assert(0);
1273 }
1274 }
1275
1276 s_wrpkt_start(ssh, pkttype, pktlen);
1277 p = ssh->pktout.body;
1278
1279 while ((argtype = va_arg(ap2, int)) != PKT_END) {
1280 switch (argtype) {
1281 case PKT_INT:
1282 argint = va_arg(ap2, int);
1283 PUT_32BIT(p, argint);
1284 p += 4;
1285 break;
1286 case PKT_CHAR:
1287 argchar = (unsigned char) va_arg(ap2, int);
1288 *p = argchar;
1289 p++;
1290 break;
1291 case PKT_DATA:
1292 argp = va_arg(ap2, unsigned char *);
1293 arglen = va_arg(ap2, int);
1294 memcpy(p, argp, arglen);
1295 p += arglen;
1296 break;
1297 case PKT_STR:
1298 argp = va_arg(ap2, unsigned char *);
1299 arglen = strlen(argp);
1300 PUT_32BIT(p, arglen);
1301 memcpy(p + 4, argp, arglen);
1302 p += 4 + arglen;
1303 break;
1304 case PKT_BIGNUM:
1305 bn = va_arg(ap2, Bignum);
1306 p += ssh1_write_bignum(p, bn);
1307 break;
1308 }
1309 }
1310 }
1311
1312 static void send_packet(Ssh ssh, int pkttype, ...)
1313 {
1314 va_list ap1, ap2;
1315 va_start(ap1, pkttype);
1316 va_start(ap2, pkttype);
1317 construct_packet(ssh, pkttype, ap1, ap2);
1318 s_wrpkt(ssh);
1319 }
1320
1321 static void defer_packet(Ssh ssh, int pkttype, ...)
1322 {
1323 va_list ap1, ap2;
1324 va_start(ap1, pkttype);
1325 va_start(ap2, pkttype);
1326 construct_packet(ssh, pkttype, ap1, ap2);
1327 s_wrpkt_defer(ssh);
1328 }
1329
1330 static int ssh_versioncmp(char *a, char *b)
1331 {
1332 char *ae, *be;
1333 unsigned long av, bv;
1334
1335 av = strtoul(a, &ae, 10);
1336 bv = strtoul(b, &be, 10);
1337 if (av != bv)
1338 return (av < bv ? -1 : +1);
1339 if (*ae == '.')
1340 ae++;
1341 if (*be == '.')
1342 be++;
1343 av = strtoul(ae, &ae, 10);
1344 bv = strtoul(be, &be, 10);
1345 if (av != bv)
1346 return (av < bv ? -1 : +1);
1347 return 0;
1348 }
1349
1350 /*
1351 * Utility routines for putting an SSH-protocol `string' and
1352 * `uint32' into a SHA state.
1353 */
1354 #include <stdio.h>
1355 static void sha_string(SHA_State * s, void *str, int len)
1356 {
1357 unsigned char lenblk[4];
1358 PUT_32BIT(lenblk, len);
1359 SHA_Bytes(s, lenblk, 4);
1360 SHA_Bytes(s, str, len);
1361 }
1362
1363 static void sha_uint32(SHA_State * s, unsigned i)
1364 {
1365 unsigned char intblk[4];
1366 PUT_32BIT(intblk, i);
1367 SHA_Bytes(s, intblk, 4);
1368 }
1369
1370 /*
1371 * SSH2 packet construction functions.
1372 */
1373 static void ssh2_pkt_ensure(Ssh ssh, int length)
1374 {
1375 if (ssh->pktout.maxlen < length) {
1376 ssh->pktout.maxlen = length + 256;
1377 ssh->pktout.data = srealloc(ssh->pktout.data,
1378 ssh->pktout.maxlen + APIEXTRA);
1379 if (!ssh->pktout.data)
1380 fatalbox("Out of memory");
1381 }
1382 }
1383 static void ssh2_pkt_adddata(Ssh ssh, void *data, int len)
1384 {
1385 ssh->pktout.length += len;
1386 ssh2_pkt_ensure(ssh, ssh->pktout.length);
1387 memcpy(ssh->pktout.data + ssh->pktout.length - len, data, len);
1388 }
1389 static void ssh2_pkt_addbyte(Ssh ssh, unsigned char byte)
1390 {
1391 ssh2_pkt_adddata(ssh, &byte, 1);
1392 }
1393 static void ssh2_pkt_init(Ssh ssh, int pkt_type)
1394 {
1395 ssh->pktout.length = 5;
1396 ssh2_pkt_addbyte(ssh, (unsigned char) pkt_type);
1397 }
1398 static void ssh2_pkt_addbool(Ssh ssh, unsigned char value)
1399 {
1400 ssh2_pkt_adddata(ssh, &value, 1);
1401 }
1402 static void ssh2_pkt_adduint32(Ssh ssh, unsigned long value)
1403 {
1404 unsigned char x[4];
1405 PUT_32BIT(x, value);
1406 ssh2_pkt_adddata(ssh, x, 4);
1407 }
1408 static void ssh2_pkt_addstring_start(Ssh ssh)
1409 {
1410 ssh2_pkt_adduint32(ssh, 0);
1411 ssh->pktout.savedpos = ssh->pktout.length;
1412 }
1413 static void ssh2_pkt_addstring_str(Ssh ssh, char *data)
1414 {
1415 ssh2_pkt_adddata(ssh, data, strlen(data));
1416 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1417 ssh->pktout.length - ssh->pktout.savedpos);
1418 }
1419 static void ssh2_pkt_addstring_data(Ssh ssh, char *data, int len)
1420 {
1421 ssh2_pkt_adddata(ssh, data, len);
1422 PUT_32BIT(ssh->pktout.data + ssh->pktout.savedpos - 4,
1423 ssh->pktout.length - ssh->pktout.savedpos);
1424 }
1425 static void ssh2_pkt_addstring(Ssh ssh, char *data)
1426 {
1427 ssh2_pkt_addstring_start(ssh);
1428 ssh2_pkt_addstring_str(ssh, data);
1429 }
1430 static char *ssh2_mpint_fmt(Bignum b, int *len)
1431 {
1432 unsigned char *p;
1433 int i, n = (bignum_bitcount(b) + 7) / 8;
1434 p = smalloc(n + 1);
1435 if (!p)
1436 fatalbox("out of memory");
1437 p[0] = 0;
1438 for (i = 1; i <= n; i++)
1439 p[i] = bignum_byte(b, n - i);
1440 i = 0;
1441 while (i <= n && p[i] == 0 && (p[i + 1] & 0x80) == 0)
1442 i++;
1443 memmove(p, p + i, n + 1 - i);
1444 *len = n + 1 - i;
1445 return p;
1446 }
1447 static void ssh2_pkt_addmp(Ssh ssh, Bignum b)
1448 {
1449 unsigned char *p;
1450 int len;
1451 p = ssh2_mpint_fmt(b, &len);
1452 ssh2_pkt_addstring_start(ssh);
1453 ssh2_pkt_addstring_data(ssh, p, len);
1454 sfree(p);
1455 }
1456
1457 /*
1458 * Construct an SSH2 final-form packet: compress it, encrypt it,
1459 * put the MAC on it. Final packet, ready to be sent, is stored in
1460 * ssh->pktout.data. Total length is returned.
1461 */
1462 static int ssh2_pkt_construct(Ssh ssh)
1463 {
1464 int cipherblk, maclen, padding, i;
1465
1466 if (ssh->logctx)
1467 log_packet(ssh->logctx, PKT_OUTGOING, ssh->pktout.data[5],
1468 ssh2_pkt_type(ssh->pkt_ctx, ssh->pktout.data[5]),
1469 ssh->pktout.data + 6, ssh->pktout.length - 6);
1470
1471 /*
1472 * Compress packet payload.
1473 */
1474 {
1475 unsigned char *newpayload;
1476 int newlen;
1477 if (ssh->cscomp &&
1478 ssh->cscomp->compress(ssh->cs_comp_ctx, ssh->pktout.data + 5,
1479 ssh->pktout.length - 5,
1480 &newpayload, &newlen)) {
1481 ssh->pktout.length = 5;
1482 ssh2_pkt_adddata(ssh, newpayload, newlen);
1483 sfree(newpayload);
1484 }
1485 }
1486
1487 /*
1488 * Add padding. At least four bytes, and must also bring total
1489 * length (minus MAC) up to a multiple of the block size.
1490 */
1491 cipherblk = ssh->cscipher ? ssh->cscipher->blksize : 8; /* block size */
1492 cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
1493 padding = 4;
1494 padding +=
1495 (cipherblk - (ssh->pktout.length + padding) % cipherblk) % cipherblk;
1496 maclen = ssh->csmac ? ssh->csmac->len : 0;
1497 ssh2_pkt_ensure(ssh, ssh->pktout.length + padding + maclen);
1498 ssh->pktout.data[4] = padding;
1499 for (i = 0; i < padding; i++)
1500 ssh->pktout.data[ssh->pktout.length + i] = random_byte();
1501 PUT_32BIT(ssh->pktout.data, ssh->pktout.length + padding - 4);
1502 if (ssh->csmac)
1503 ssh->csmac->generate(ssh->cs_mac_ctx, ssh->pktout.data,
1504 ssh->pktout.length + padding,
1505 ssh->v2_outgoing_sequence);
1506 ssh->v2_outgoing_sequence++; /* whether or not we MACed */
1507
1508 if (ssh->cscipher)
1509 ssh->cscipher->encrypt(ssh->cs_cipher_ctx,
1510 ssh->pktout.data, ssh->pktout.length + padding);
1511
1512 /* Ready-to-send packet starts at ssh->pktout.data. We return length. */
1513 return ssh->pktout.length + padding + maclen;
1514 }
1515
1516 /*
1517 * Construct and send an SSH2 packet immediately.
1518 */
1519 static void ssh2_pkt_send(Ssh ssh)
1520 {
1521 int len;
1522 int backlog;
1523 len = ssh2_pkt_construct(ssh);
1524 backlog = sk_write(ssh->s, ssh->pktout.data, len);
1525 if (backlog > SSH_MAX_BACKLOG)
1526 ssh_throttle_all(ssh, 1, backlog);
1527 }
1528
1529 /*
1530 * Construct an SSH2 packet and add it to a deferred data block.
1531 * Useful for sending multiple packets in a single sk_write() call,
1532 * to prevent a traffic-analysing listener from being able to work
1533 * out the length of any particular packet (such as the password
1534 * packet).
1535 *
1536 * Note that because SSH2 sequence-numbers its packets, this can
1537 * NOT be used as an m4-style `defer' allowing packets to be
1538 * constructed in one order and sent in another.
1539 */
1540 static void ssh2_pkt_defer(Ssh ssh)
1541 {
1542 int len = ssh2_pkt_construct(ssh);
1543 if (ssh->deferred_len + len > ssh->deferred_size) {
1544 ssh->deferred_size = ssh->deferred_len + len + 128;
1545 ssh->deferred_send_data = srealloc(ssh->deferred_send_data,
1546 ssh->deferred_size);
1547 }
1548 memcpy(ssh->deferred_send_data + ssh->deferred_len, ssh->pktout.data, len);
1549 ssh->deferred_len += len;
1550 }
1551
1552 /*
1553 * Send the whole deferred data block constructed by
1554 * ssh2_pkt_defer() or SSH1's defer_packet().
1555 */
1556 static void ssh_pkt_defersend(Ssh ssh)
1557 {
1558 int backlog;
1559 backlog = sk_write(ssh->s, ssh->deferred_send_data, ssh->deferred_len);
1560 ssh->deferred_len = ssh->deferred_size = 0;
1561 sfree(ssh->deferred_send_data);
1562 ssh->deferred_send_data = NULL;
1563 if (backlog > SSH_MAX_BACKLOG)
1564 ssh_throttle_all(ssh, 1, backlog);
1565 }
1566
1567 #if 0
1568 void bndebug(char *string, Bignum b)
1569 {
1570 unsigned char *p;
1571 int i, len;
1572 p = ssh2_mpint_fmt(b, &len);
1573 debug(("%s", string));
1574 for (i = 0; i < len; i++)
1575 debug((" %02x", p[i]));
1576 debug(("\n"));
1577 sfree(p);
1578 }
1579 #endif
1580
1581 static void sha_mpint(SHA_State * s, Bignum b)
1582 {
1583 unsigned char *p;
1584 int len;
1585 p = ssh2_mpint_fmt(b, &len);
1586 sha_string(s, p, len);
1587 sfree(p);
1588 }
1589
1590 /*
1591 * SSH2 packet decode functions.
1592 */
1593 static unsigned long ssh2_pkt_getuint32(Ssh ssh)
1594 {
1595 unsigned long value;
1596 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1597 return 0; /* arrgh, no way to decline (FIXME?) */
1598 value = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1599 ssh->pktin.savedpos += 4;
1600 return value;
1601 }
1602 static int ssh2_pkt_getbool(Ssh ssh)
1603 {
1604 unsigned long value;
1605 if (ssh->pktin.length - ssh->pktin.savedpos < 1)
1606 return 0; /* arrgh, no way to decline (FIXME?) */
1607 value = ssh->pktin.data[ssh->pktin.savedpos] != 0;
1608 ssh->pktin.savedpos++;
1609 return value;
1610 }
1611 static void ssh2_pkt_getstring(Ssh ssh, char **p, int *length)
1612 {
1613 int len;
1614 *p = NULL;
1615 *length = 0;
1616 if (ssh->pktin.length - ssh->pktin.savedpos < 4)
1617 return;
1618 len = GET_32BIT(ssh->pktin.data + ssh->pktin.savedpos);
1619 if (len < 0)
1620 return;
1621 *length = len;
1622 ssh->pktin.savedpos += 4;
1623 if (ssh->pktin.length - ssh->pktin.savedpos < *length)
1624 return;
1625 *p = ssh->pktin.data + ssh->pktin.savedpos;
1626 ssh->pktin.savedpos += *length;
1627 }
1628 static Bignum ssh2_pkt_getmp(Ssh ssh)
1629 {
1630 char *p;
1631 int length;
1632 Bignum b;
1633
1634 ssh2_pkt_getstring(ssh, &p, &length);
1635 if (!p)
1636 return NULL;
1637 if (p[0] & 0x80) {
1638 bombout((ssh,"internal error: Can't handle negative mpints"));
1639 return NULL;
1640 }
1641 b = bignum_from_bytes(p, length);
1642 return b;
1643 }
1644
1645 /*
1646 * Helper function to add an SSH2 signature blob to a packet.
1647 * Expects to be shown the public key blob as well as the signature
1648 * blob. Normally works just like ssh2_pkt_addstring, but will
1649 * fiddle with the signature packet if necessary for
1650 * BUG_SSH2_RSA_PADDING.
1651 */
1652 static void ssh2_add_sigblob(Ssh ssh, void *pkblob_v, int pkblob_len,
1653 void *sigblob_v, int sigblob_len)
1654 {
1655 unsigned char *pkblob = (unsigned char *)pkblob_v;
1656 unsigned char *sigblob = (unsigned char *)sigblob_v;
1657
1658 /* dmemdump(pkblob, pkblob_len); */
1659 /* dmemdump(sigblob, sigblob_len); */
1660
1661 /*
1662 * See if this is in fact an ssh-rsa signature and a buggy
1663 * server; otherwise we can just do this the easy way.
1664 */
1665 if ((ssh->remote_bugs & BUG_SSH2_RSA_PADDING) &&
1666 (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
1667 int pos, len, siglen;
1668
1669 /*
1670 * Find the byte length of the modulus.
1671 */
1672
1673 pos = 4+7; /* skip over "ssh-rsa" */
1674 pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
1675 len = GET_32BIT(pkblob+pos); /* find length of modulus */
1676 pos += 4; /* find modulus itself */
1677 while (len > 0 && pkblob[pos] == 0)
1678 len--, pos++;
1679 /* debug(("modulus length is %d\n", len)); */
1680
1681 /*
1682 * Now find the signature integer.
1683 */
1684 pos = 4+7; /* skip over "ssh-rsa" */
1685 siglen = GET_32BIT(sigblob+pos);
1686 /* debug(("signature length is %d\n", siglen)); */
1687
1688 if (len != siglen) {
1689 unsigned char newlen[4];
1690 ssh2_pkt_addstring_start(ssh);
1691 ssh2_pkt_addstring_data(ssh, sigblob, pos);
1692 /* dmemdump(sigblob, pos); */
1693 pos += 4; /* point to start of actual sig */
1694 PUT_32BIT(newlen, len);
1695 ssh2_pkt_addstring_data(ssh, newlen, 4);
1696 /* dmemdump(newlen, 4); */
1697 newlen[0] = 0;
1698 while (len-- > siglen) {
1699 ssh2_pkt_addstring_data(ssh, newlen, 1);
1700 /* dmemdump(newlen, 1); */
1701 }
1702 ssh2_pkt_addstring_data(ssh, sigblob+pos, siglen);
1703 /* dmemdump(sigblob+pos, siglen); */
1704 return;
1705 }
1706
1707 /* Otherwise fall through and do it the easy way. */
1708 }
1709
1710 ssh2_pkt_addstring_start(ssh);
1711 ssh2_pkt_addstring_data(ssh, sigblob, sigblob_len);
1712 }
1713
1714 /*
1715 * Examine the remote side's version string and compare it against
1716 * a list of known buggy implementations.
1717 */
1718 static void ssh_detect_bugs(Ssh ssh, char *vstring)
1719 {
1720 char *imp; /* pointer to implementation part */
1721 imp = vstring;
1722 imp += strcspn(imp, "-");
1723 if (*imp) imp++;
1724 imp += strcspn(imp, "-");
1725 if (*imp) imp++;
1726
1727 ssh->remote_bugs = 0;
1728
1729 if (cfg.sshbug_ignore1 == BUG_ON ||
1730 (cfg.sshbug_ignore1 == BUG_AUTO &&
1731 (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
1732 !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
1733 !strcmp(imp, "1.2.22") || !strcmp(imp, "Cisco-1.25")))) {
1734 /*
1735 * These versions don't support SSH1_MSG_IGNORE, so we have
1736 * to use a different defence against password length
1737 * sniffing.
1738 */
1739 ssh->remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
1740 logevent("We believe remote version has SSH1 ignore bug");
1741 }
1742
1743 if (cfg.sshbug_plainpw1 == BUG_ON ||
1744 (cfg.sshbug_plainpw1 == BUG_AUTO &&
1745 (!strcmp(imp, "Cisco-1.25")))) {
1746 /*
1747 * These versions need a plain password sent; they can't
1748 * handle having a null and a random length of data after
1749 * the password.
1750 */
1751 ssh->remote_bugs |= BUG_NEEDS_SSH1_PLAIN_PASSWORD;
1752 logevent("We believe remote version needs a plain SSH1 password");
1753 }
1754
1755 if (cfg.sshbug_rsa1 == BUG_ON ||
1756 (cfg.sshbug_rsa1 == BUG_AUTO &&
1757 (!strcmp(imp, "Cisco-1.25")))) {
1758 /*
1759 * These versions apparently have no clue whatever about
1760 * RSA authentication and will panic and die if they see
1761 * an AUTH_RSA message.
1762 */
1763 ssh->remote_bugs |= BUG_CHOKES_ON_RSA;
1764 logevent("We believe remote version can't handle RSA authentication");
1765 }
1766
1767 if (cfg.sshbug_hmac2 == BUG_ON ||
1768 (cfg.sshbug_hmac2 == BUG_AUTO &&
1769 (wc_match("2.1.0*", imp) || wc_match("2.0.*", imp) ||
1770 wc_match("2.2.0*", imp) || wc_match("2.3.0*", imp) ||
1771 wc_match("2.1 *", imp)))) {
1772 /*
1773 * These versions have the HMAC bug.
1774 */
1775 ssh->remote_bugs |= BUG_SSH2_HMAC;
1776 logevent("We believe remote version has SSH2 HMAC bug");
1777 }
1778
1779 if (cfg.sshbug_derivekey2 == BUG_ON ||
1780 (cfg.sshbug_derivekey2 == BUG_AUTO &&
1781 (wc_match("2.0.0*", imp) || wc_match("2.0.1[01]*", imp) ))) {
1782 /*
1783 * These versions have the key-derivation bug (failing to
1784 * include the literal shared secret in the hashes that
1785 * generate the keys).
1786 */
1787 ssh->remote_bugs |= BUG_SSH2_DERIVEKEY;
1788 logevent("We believe remote version has SSH2 key-derivation bug");
1789 }
1790
1791 if (cfg.sshbug_rsapad2 == BUG_ON ||
1792 (cfg.sshbug_rsapad2 == BUG_AUTO &&
1793 (wc_match("OpenSSH_2.[5-9]*", imp) ||
1794 wc_match("OpenSSH_3.[0-2]*", imp)))) {
1795 /*
1796 * These versions have the SSH2 RSA padding bug.
1797 */
1798 ssh->remote_bugs |= BUG_SSH2_RSA_PADDING;
1799 logevent("We believe remote version has SSH2 RSA padding bug");
1800 }
1801
1802 if (cfg.sshbug_dhgex2 == BUG_ON) {
1803 /*
1804 * User specified the SSH2 DH GEX bug.
1805 */
1806 ssh->remote_bugs |= BUG_SSH2_DH_GEX;
1807 logevent("We believe remote version has SSH2 DH group exchange bug");
1808 }
1809 }
1810
1811 static int do_ssh_init(Ssh ssh, unsigned char c)
1812 {
1813 struct do_ssh_init_state {
1814 int vslen;
1815 char version[10];
1816 char *vstring;
1817 int vstrsize;
1818 int i;
1819 int proto1, proto2;
1820 };
1821 crState(do_ssh_init_state);
1822
1823 crBegin(ssh->do_ssh_init_crstate);
1824
1825 /* Search for the string "SSH-" in the input. */
1826 s->i = 0;
1827 while (1) {
1828 static const int transS[] = { 1, 2, 2, 1 };
1829 static const int transH[] = { 0, 0, 3, 0 };
1830 static const int transminus[] = { 0, 0, 0, -1 };
1831 if (c == 'S')
1832 s->i = transS[s->i];
1833 else if (c == 'H')
1834 s->i = transH[s->i];
1835 else if (c == '-')
1836 s->i = transminus[s->i];
1837 else
1838 s->i = 0;
1839 if (s->i < 0)
1840 break;
1841 crReturn(1); /* get another character */
1842 }
1843
1844 s->vstrsize = 16;
1845 s->vstring = smalloc(s->vstrsize);
1846 strcpy(s->vstring, "SSH-");
1847 s->vslen = 4;
1848 s->i = 0;
1849 while (1) {
1850 crReturn(1); /* get another char */
1851 if (s->vslen >= s->vstrsize - 1) {
1852 s->vstrsize += 16;
1853 s->vstring = srealloc(s->vstring, s->vstrsize);
1854 }
1855 s->vstring[s->vslen++] = c;
1856 if (s->i >= 0) {
1857 if (c == '-') {
1858 s->version[s->i] = '\0';
1859 s->i = -1;
1860 } else if (s->i < sizeof(s->version) - 1)
1861 s->version[s->i++] = c;
1862 } else if (c == '\n')
1863 break;
1864 }
1865
1866 ssh->agentfwd_enabled = FALSE;
1867 ssh->rdpkt2_state.incoming_sequence = 0;
1868
1869 s->vstring[s->vslen] = 0;
1870 s->vstring[strcspn(s->vstring, "\r\n")] = '\0';/* remove EOL chars */
1871 {
1872 char *vlog;
1873 vlog = smalloc(20 + s->vslen);
1874 sprintf(vlog, "Server version: %s", s->vstring);
1875 logevent(vlog);
1876 sfree(vlog);
1877 }
1878 ssh_detect_bugs(ssh, s->vstring);
1879
1880 /*
1881 * Decide which SSH protocol version to support.
1882 */
1883
1884 /* Anything strictly below "2.0" means protocol 1 is supported. */
1885 s->proto1 = ssh_versioncmp(s->version, "2.0") < 0;
1886 /* Anything greater or equal to "1.99" means protocol 2 is supported. */
1887 s->proto2 = ssh_versioncmp(s->version, "1.99") >= 0;
1888
1889 if (cfg.sshprot == 0 && !s->proto1) {
1890 bombout((ssh,"SSH protocol version 1 required by user but not provided by server"));
1891 crReturn(0);
1892 }
1893 if (cfg.sshprot == 3 && !s->proto2) {
1894 bombout((ssh,"SSH protocol version 2 required by user but not provided by server"));
1895 crReturn(0);
1896 }
1897
1898 if (s->proto2 && (cfg.sshprot >= 2 || !s->proto1)) {
1899 /*
1900 * Use v2 protocol.
1901 */
1902 char verstring[80], vlog[100];
1903 sprintf(verstring, "SSH-2.0-%s", sshver);
1904 SHA_Init(&ssh->exhashbase);
1905 /*
1906 * Hash our version string and their version string.
1907 */
1908 sha_string(&ssh->exhashbase, verstring, strlen(verstring));
1909 sha_string(&ssh->exhashbase, s->vstring, strcspn(s->vstring, "\r\n"));
1910 sprintf(vlog, "We claim version: %s", verstring);
1911 logevent(vlog);
1912 strcat(verstring, "\n");
1913 logevent("Using SSH protocol version 2");
1914 sk_write(ssh->s, verstring, strlen(verstring));
1915 ssh->protocol = ssh2_protocol;
1916 ssh->version = 2;
1917 ssh->s_rdpkt = ssh2_rdpkt;
1918 } else {
1919 /*
1920 * Use v1 protocol.
1921 */
1922 char verstring[80], vlog[100];
1923 sprintf(verstring, "SSH-%s-%s",
1924 (ssh_versioncmp(s->version, "1.5") <= 0 ? s->version : "1.5"),
1925 sshver);
1926 sprintf(vlog, "We claim version: %s", verstring);
1927 logevent(vlog);
1928 strcat(verstring, "\n");
1929
1930 logevent("Using SSH protocol version 1");
1931 sk_write(ssh->s, verstring, strlen(verstring));
1932 ssh->protocol = ssh1_protocol;
1933 ssh->version = 1;
1934 ssh->s_rdpkt = ssh1_rdpkt;
1935 }
1936 ssh->state = SSH_STATE_BEFORE_SIZE;
1937
1938 sfree(s->vstring);
1939
1940 crFinish(0);
1941 }
1942
1943 static void ssh_gotdata(Ssh ssh, unsigned char *data, int datalen)
1944 {
1945 crBegin(ssh->ssh_gotdata_crstate);
1946
1947 /*
1948 * To begin with, feed the characters one by one to the
1949 * protocol initialisation / selection function do_ssh_init().
1950 * When that returns 0, we're done with the initial greeting
1951 * exchange and can move on to packet discipline.
1952 */
1953 while (1) {
1954 int ret; /* need not be kept across crReturn */
1955 if (datalen == 0)
1956 crReturnV; /* more data please */
1957 ret = do_ssh_init(ssh, *data);
1958 data++;
1959 datalen--;
1960 if (ret == 0)
1961 break;
1962 }
1963
1964 /*
1965 * We emerge from that loop when the initial negotiation is
1966 * over and we have selected an s_rdpkt function. Now pass
1967 * everything to s_rdpkt, and then pass the resulting packets
1968 * to the proper protocol handler.
1969 */
1970 if (datalen == 0)
1971 crReturnV;
1972 while (1) {
1973 while (datalen > 0) {
1974 if (ssh->s_rdpkt(ssh, &data, &datalen) == 0) {
1975 if (ssh->state == SSH_STATE_CLOSED) {
1976 return;
1977 }
1978 ssh->protocol(ssh, NULL, 0, 1);
1979 if (ssh->state == SSH_STATE_CLOSED) {
1980 return;
1981 }
1982 }
1983 }
1984 crReturnV;
1985 }
1986 crFinishV;
1987 }
1988
1989 static int ssh_closing(Plug plug, char *error_msg, int error_code,
1990 int calling_back)
1991 {
1992 Ssh ssh = (Ssh) plug;
1993 ssh->state = SSH_STATE_CLOSED;
1994 if (ssh->s) {
1995 sk_close(ssh->s);
1996 ssh->s = NULL;
1997 }
1998 if (error_msg) {
1999 /* A socket error has occurred. */
2000 logevent(error_msg);
2001 connection_fatal(ssh->frontend, error_msg);
2002 } else {
2003 /* Otherwise, the remote side closed the connection normally. */
2004 }
2005 return 0;
2006 }
2007
2008 static int ssh_receive(Plug plug, int urgent, char *data, int len)
2009 {
2010 Ssh ssh = (Ssh) plug;
2011 ssh_gotdata(ssh, data, len);
2012 if (ssh->state == SSH_STATE_CLOSED) {
2013 if (ssh->s) {
2014 sk_close(ssh->s);
2015 ssh->s = NULL;
2016 }
2017 return 0;
2018 }
2019 return 1;
2020 }
2021
2022 static void ssh_sent(Plug plug, int bufsize)
2023 {
2024 Ssh ssh = (Ssh) plug;
2025 /*
2026 * If the send backlog on the SSH socket itself clears, we
2027 * should unthrottle the whole world if it was throttled.
2028 */
2029 if (bufsize < SSH_MAX_BACKLOG)
2030 ssh_throttle_all(ssh, 0, bufsize);
2031 }
2032
2033 /*
2034 * Connect to specified host and port.
2035 * Returns an error message, or NULL on success.
2036 * Also places the canonical host name into `realhost'. It must be
2037 * freed by the caller.
2038 */
2039 static char *connect_to_host(Ssh ssh, char *host, int port,
2040 char **realhost, int nodelay)
2041 {
2042 static const struct plug_function_table fn_table = {
2043 ssh_closing,
2044 ssh_receive,
2045 ssh_sent,
2046 NULL
2047 };
2048
2049 SockAddr addr;
2050 char *err;
2051
2052 ssh->savedhost = smalloc(1 + strlen(host));
2053 if (!ssh->savedhost)
2054 fatalbox("Out of memory");
2055 strcpy(ssh->savedhost, host);
2056
2057 if (port < 0)
2058 port = 22; /* default ssh port */
2059 ssh->savedport = port;
2060
2061 /*
2062 * Try to find host.
2063 */
2064 logeventf(ssh, "Looking up host \"%s\"", host);
2065 addr = name_lookup(host, port, realhost);
2066 if ((err = sk_addr_error(addr)))
2067 return err;
2068
2069 /*
2070 * Open socket.
2071 */
2072 {
2073 char addrbuf[100];
2074 sk_getaddr(addr, addrbuf, 100);
2075 logeventf(ssh, "Connecting to %s port %d", addrbuf, port);
2076 }
2077 ssh->fn = &fn_table;
2078 ssh->s = new_connection(addr, *realhost, port, 0, 1, nodelay, (Plug) ssh);
2079 if ((err = sk_socket_error(ssh->s))) {
2080 ssh->s = NULL;
2081 return err;
2082 }
2083
2084 return NULL;
2085 }
2086
2087 /*
2088 * Throttle or unthrottle the SSH connection.
2089 */
2090 static void ssh1_throttle(Ssh ssh, int adjust)
2091 {
2092 int old_count = ssh->v1_throttle_count;
2093 ssh->v1_throttle_count += adjust;
2094 assert(ssh->v1_throttle_count >= 0);
2095 if (ssh->v1_throttle_count && !old_count) {
2096 sk_set_frozen(ssh->s, 1);
2097 } else if (!ssh->v1_throttle_count && old_count) {
2098 sk_set_frozen(ssh->s, 0);
2099 }
2100 }
2101
2102 /*
2103 * Throttle or unthrottle _all_ local data streams (for when sends
2104 * on the SSH connection itself back up).
2105 */
2106 static void ssh_throttle_all(Ssh ssh, int enable, int bufsize)
2107 {
2108 int i;
2109 struct ssh_channel *c;
2110
2111 if (enable == ssh->throttled_all)
2112 return;
2113 ssh->throttled_all = enable;
2114 ssh->overall_bufsize = bufsize;
2115 if (!ssh->channels)
2116 return;
2117 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
2118 switch (c->type) {
2119 case CHAN_MAINSESSION:
2120 /*
2121 * This is treated separately, outside the switch.
2122 */
2123 break;
2124 case CHAN_X11:
2125 x11_override_throttle(c->u.x11.s, enable);
2126 break;
2127 case CHAN_AGENT:
2128 /* Agent channels require no buffer management. */
2129 break;
2130 case CHAN_SOCKDATA:
2131 pfd_override_throttle(c->u.x11.s, enable);
2132 break;
2133 }
2134 }
2135 }
2136
2137 /*
2138 * Username and password input, abstracted off into routines
2139 * reusable in several places - even between SSH1 and SSH2.
2140 */
2141
2142 /* Set up a username or password input loop on a given buffer. */
2143 void setup_userpass_input(Ssh ssh, char *buffer, int buflen, int echo)
2144 {
2145 ssh->userpass_input_buffer = buffer;
2146 ssh->userpass_input_buflen = buflen;
2147 ssh->userpass_input_bufpos = 0;
2148 ssh->userpass_input_echo = echo;
2149 }
2150
2151 /*
2152 * Process some terminal data in the course of username/password
2153 * input. Returns >0 for success (line of input returned in
2154 * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
2155 * for inconclusive (keep waiting for more input please).
2156 */
2157 int process_userpass_input(Ssh ssh, unsigned char *in, int inlen)
2158 {
2159 char c;
2160
2161 while (inlen--) {
2162 switch (c = *in++) {
2163 case 10:
2164 case 13:
2165 ssh->userpass_input_buffer[ssh->userpass_input_bufpos] = 0;
2166 ssh->userpass_input_buffer[ssh->userpass_input_buflen-1] = 0;
2167 return +1;
2168 break;
2169 case 8:
2170 case 127:
2171 if (ssh->userpass_input_bufpos > 0) {
2172 if (ssh->userpass_input_echo)
2173 c_write_str(ssh, "\b \b");
2174 ssh->userpass_input_bufpos--;
2175 }
2176 break;
2177 case 21:
2178 case 27:
2179 while (ssh->userpass_input_bufpos > 0) {
2180 if (ssh->userpass_input_echo)
2181 c_write_str(ssh, "\b \b");
2182 ssh->userpass_input_bufpos--;
2183 }
2184 break;
2185 case 3:
2186 case 4:
2187 return -1;
2188 break;
2189 default:
2190 if (((c >= ' ' && c <= '~') ||
2191 ((unsigned char) c >= 160))
2192 && ssh->userpass_input_bufpos < ssh->userpass_input_buflen-1) {
2193 ssh->userpass_input_buffer[ssh->userpass_input_bufpos++] = c;
2194 if (ssh->userpass_input_echo)
2195 c_write(ssh, &c, 1);
2196 }
2197 break;
2198 }
2199 }
2200 return 0;
2201 }
2202
2203 /*
2204 * Handle the key exchange and user authentication phases.
2205 */
2206 static int do_ssh1_login(Ssh ssh, unsigned char *in, int inlen, int ispkt)
2207 {
2208 int i, j;
2209 unsigned char cookie[8];
2210 struct RSAKey servkey, hostkey;
2211 struct MD5Context md5c;
2212 struct do_ssh1_login_state {
2213 int len;
2214 unsigned char *rsabuf, *keystr1, *keystr2;
2215 unsigned long supported_ciphers_mask, supported_auths_mask;
2216 int tried_publickey, tried_agent;
2217 int tis_auth_refused, ccard_auth_refused;
2218 unsigned char session_id[16];
2219 int cipher_type;
2220 char username[100];
2221 void *publickey_blob;
2222 int publickey_bloblen;
2223 char password[100];
2224 char prompt[200];
2225 int pos;
2226 char c;
2227 int pwpkt_type;
2228 unsigned char request[5], *response, *p;
2229 int responselen;
2230 int keyi, nkeys;
2231 int authed;
2232 struct RSAKey key;
2233 Bignum challenge;
2234 char *commentp;
2235 int commentlen;
2236 };
2237 crState(do_ssh1_login_state);
2238
2239 crBegin(ssh->do_ssh1_login_crstate);
2240
2241 if (!ispkt)
2242 crWaitUntil(ispkt);
2243
2244 if (ssh->pktin.type != SSH1_SMSG_PUBLIC_KEY) {
2245 bombout((ssh,"Public key packet not received"));
2246 crReturn(0);
2247 }
2248
2249 logevent("Received public keys");
2250
2251 memcpy(cookie, ssh->pktin.body, 8);
2252
2253 i = makekey(ssh->pktin.body + 8, &servkey, &s->keystr1, 0);
2254 j = makekey(ssh->pktin.body + 8 + i, &hostkey, &s->keystr2, 0);
2255
2256 /*
2257 * Log the host key fingerprint.
2258 */
2259 {
2260 char logmsg[80];
2261 logevent("Host key fingerprint is:");
2262 strcpy(logmsg, " ");
2263 hostkey.comment = NULL;
2264 rsa_fingerprint(logmsg + strlen(logmsg),
2265 sizeof(logmsg) - strlen(logmsg), &hostkey);
2266 logevent(logmsg);
2267 }
2268
2269 ssh->v1_remote_protoflags = GET_32BIT(ssh->pktin.body + 8 + i + j);
2270 s->supported_ciphers_mask = GET_32BIT(ssh->pktin.body + 12 + i + j);
2271 s->supported_auths_mask = GET_32BIT(ssh->pktin.body + 16 + i + j);
2272
2273 ssh->v1_local_protoflags =
2274 ssh->v1_remote_protoflags & SSH1_PROTOFLAGS_SUPPORTED;
2275 ssh->v1_local_protoflags |= SSH1_PROTOFLAG_SCREEN_NUMBER;
2276
2277 MD5Init(&md5c);
2278 MD5Update(&md5c, s->keystr2, hostkey.bytes);
2279 MD5Update(&md5c, s->keystr1, servkey.bytes);
2280 MD5Update(&md5c, ssh->pktin.body, 8);
2281 MD5Final(s->session_id, &md5c);
2282
2283 for (i = 0; i < 32; i++)
2284 ssh->session_key[i] = random_byte();
2285
2286 s->len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
2287
2288 s->rsabuf = smalloc(s->len);
2289 if (!s->rsabuf)
2290 fatalbox("Out of memory");
2291
2292 /*
2293 * Verify the host key.
2294 */
2295 {
2296 /*
2297 * First format the key into a string.
2298 */
2299 int len = rsastr_len(&hostkey);
2300 char fingerprint[100];
2301 char *keystr = smalloc(len);
2302 if (!keystr)
2303 fatalbox("Out of memory");
2304 rsastr_fmt(keystr, &hostkey);
2305 rsa_fingerprint(fingerprint, sizeof(fingerprint), &hostkey);
2306 verify_ssh_host_key(ssh->frontend,
2307 ssh->savedhost, ssh->savedport, "rsa", keystr,
2308 fingerprint);
2309 sfree(keystr);
2310 }
2311
2312 for (i = 0; i < 32; i++) {
2313 s->rsabuf[i] = ssh->session_key[i];
2314 if (i < 16)
2315 s->rsabuf[i] ^= s->session_id[i];
2316 }
2317
2318 if (hostkey.bytes > servkey.bytes) {
2319 rsaencrypt(s->rsabuf, 32, &servkey);
2320 rsaencrypt(s->rsabuf, servkey.bytes, &hostkey);
2321 } else {
2322 rsaencrypt(s->rsabuf, 32, &hostkey);
2323 rsaencrypt(s->rsabuf, hostkey.bytes, &servkey);
2324 }
2325
2326 logevent("Encrypted session key");
2327
2328 {
2329 int cipher_chosen = 0, warn = 0;
2330 char *cipher_string = NULL;
2331 int i;
2332 for (i = 0; !cipher_chosen && i < CIPHER_MAX; i++) {
2333 int next_cipher = cfg.ssh_cipherlist[i];
2334 if (next_cipher == CIPHER_WARN) {
2335 /* If/when we choose a cipher, warn about it */
2336 warn = 1;
2337 } else if (next_cipher == CIPHER_AES) {
2338 /* XXX Probably don't need to mention this. */
2339 logevent("AES not supported in SSH1, skipping");
2340 } else {
2341 switch (next_cipher) {
2342 case CIPHER_3DES: s->cipher_type = SSH_CIPHER_3DES;
2343 cipher_string = "3DES"; break;
2344 case CIPHER_BLOWFISH: s->cipher_type = SSH_CIPHER_BLOWFISH;
2345 cipher_string = "Blowfish"; break;
2346 case CIPHER_DES: s->cipher_type = SSH_CIPHER_DES;
2347 cipher_string = "single-DES"; break;
2348 }
2349 if (s->supported_ciphers_mask & (1 << s->cipher_type))
2350 cipher_chosen = 1;
2351 }
2352 }
2353 if (!cipher_chosen) {
2354 if ((s->supported_ciphers_mask & (1 << SSH_CIPHER_3DES)) == 0)
2355 bombout((ssh,"Server violates SSH 1 protocol by not "
2356 "supporting 3DES encryption"));
2357 else
2358 /* shouldn't happen */
2359 bombout((ssh,"No supported ciphers found"));
2360 crReturn(0);
2361 }
2362
2363 /* Warn about chosen cipher if necessary. */
2364 if (warn)
2365 askcipher(ssh->frontend, cipher_string, 0);
2366 }
2367
2368 switch (s->cipher_type) {
2369 case SSH_CIPHER_3DES:
2370 logevent("Using 3DES encryption");
2371 break;
2372 case SSH_CIPHER_DES:
2373 logevent("Using single-DES encryption");
2374 break;
2375 case SSH_CIPHER_BLOWFISH:
2376 logevent("Using Blowfish encryption");
2377 break;
2378 }
2379
2380 send_packet(ssh, SSH1_CMSG_SESSION_KEY,
2381 PKT_CHAR, s->cipher_type,
2382 PKT_DATA, cookie, 8,
2383 PKT_CHAR, (s->len * 8) >> 8, PKT_CHAR, (s->len * 8) & 0xFF,
2384 PKT_DATA, s->rsabuf, s->len,
2385 PKT_INT, ssh->v1_local_protoflags, PKT_END);
2386
2387 logevent("Trying to enable encryption...");
2388
2389 sfree(s->rsabuf);
2390
2391 ssh->cipher = (s->cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish_ssh1 :
2392 s->cipher_type == SSH_CIPHER_DES ? &ssh_des :
2393 &ssh_3des);
2394 ssh->v1_cipher_ctx = ssh->cipher->make_context();
2395 ssh->cipher->sesskey(ssh->v1_cipher_ctx, ssh->session_key);
2396 logeventf(ssh, "Initialised %s encryption", ssh->cipher->text_name);
2397
2398 ssh->crcda_ctx = crcda_make_context();
2399 logevent("Installing CRC compensation attack detector");
2400
2401 crWaitUntil(ispkt);
2402
2403 if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2404 bombout((ssh,"Encryption not successfully enabled"));
2405 crReturn(0);
2406 }
2407
2408 logevent("Successfully started encryption");
2409
2410 fflush(stdout);
2411 {
2412 if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
2413 if (ssh_get_line && !ssh_getline_pw_only) {
2414 if (!ssh_get_line("login as: ",
2415 s->username, sizeof(s->username), FALSE)) {
2416 /*
2417 * get_line failed to get a username.
2418 * Terminate.
2419 */
2420 logevent("No username provided. Abandoning session.");
2421 ssh->state = SSH_STATE_CLOSED;
2422 crReturn(1);
2423 }
2424 } else {
2425 int ret; /* need not be kept over crReturn */
2426 c_write_str(ssh, "login as: ");
2427 ssh->send_ok = 1;
2428
2429 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
2430 do {
2431 crWaitUntil(!ispkt);
2432 ret = process_userpass_input(ssh, in, inlen);
2433 } while (ret == 0);
2434 if (ret < 0)
2435 cleanup_exit(0);
2436 c_write_str(ssh, "\r\n");
2437 }
2438 } else {
2439 strncpy(s->username, cfg.username, sizeof(s->username));
2440 s->username[sizeof(s->username)-1] = '\0';
2441 }
2442
2443 send_packet(ssh, SSH1_CMSG_USER, PKT_STR, s->username, PKT_END);
2444 {
2445 char userlog[22 + sizeof(s->username)];
2446 sprintf(userlog, "Sent username \"%s\"", s->username);
2447 logevent(userlog);
2448 if (flags & FLAG_INTERACTIVE &&
2449 (!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
2450 strcat(userlog, "\r\n");
2451 c_write_str(ssh, userlog);
2452 }
2453 }
2454 }
2455
2456 crWaitUntil(ispkt);
2457
2458 if ((ssh->remote_bugs & BUG_CHOKES_ON_RSA)) {
2459 /* We must not attempt PK auth. Pretend we've already tried it. */
2460 s->tried_publickey = s->tried_agent = 1;
2461 } else {
2462 s->tried_publickey = s->tried_agent = 0;
2463 }
2464 s->tis_auth_refused = s->ccard_auth_refused = 0;
2465 /* Load the public half of cfg.keyfile so we notice if it's in Pageant */
2466 if (*cfg.keyfile) {
2467 if (!rsakey_pubblob(cfg.keyfile,
2468 &s->publickey_blob, &s->publickey_bloblen))
2469 s->publickey_blob = NULL;
2470 } else
2471 s->publickey_blob = NULL;
2472
2473 while (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2474 s->pwpkt_type = SSH1_CMSG_AUTH_PASSWORD;
2475
2476 if (agent_exists() && !s->tried_agent) {
2477 /*
2478 * Attempt RSA authentication using Pageant.
2479 */
2480 void *r;
2481
2482 s->authed = FALSE;
2483 s->tried_agent = 1;
2484 logevent("Pageant is running. Requesting keys.");
2485
2486 /* Request the keys held by the agent. */
2487 PUT_32BIT(s->request, 1);
2488 s->request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
2489 agent_query(s->request, 5, &r, &s->responselen);
2490 s->response = (unsigned char *) r;
2491 if (s->response && s->responselen >= 5 &&
2492 s->response[4] == SSH1_AGENT_RSA_IDENTITIES_ANSWER) {
2493 s->p = s->response + 5;
2494 s->nkeys = GET_32BIT(s->p);
2495 s->p += 4;
2496 {
2497 char buf[64];
2498 sprintf(buf, "Pageant has %d SSH1 keys", s->nkeys);
2499 logevent(buf);
2500 }
2501 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
2502 {
2503 char buf[64];
2504 sprintf(buf, "Trying Pageant key #%d", s->keyi);
2505 logevent(buf);
2506 }
2507 if (s->publickey_blob &&
2508 !memcmp(s->p, s->publickey_blob,
2509 s->publickey_bloblen)) {
2510 logevent("This key matches configured key file");
2511 s->tried_publickey = 1;
2512 }
2513 s->p += 4;
2514 s->p += ssh1_read_bignum(s->p, &s->key.exponent);
2515 s->p += ssh1_read_bignum(s->p, &s->key.modulus);
2516 s->commentlen = GET_32BIT(s->p);
2517 s->p += 4;
2518 s->commentp = s->p;
2519 s->p += s->commentlen;
2520 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2521 PKT_BIGNUM, s->key.modulus, PKT_END);
2522 crWaitUntil(ispkt);
2523 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2524 logevent("Key refused");
2525 continue;
2526 }
2527 logevent("Received RSA challenge");
2528 ssh1_read_bignum(ssh->pktin.body, &s->challenge);
2529 {
2530 char *agentreq, *q, *ret;
2531 void *vret;
2532 int len, retlen;
2533 len = 1 + 4; /* message type, bit count */
2534 len += ssh1_bignum_length(s->key.exponent);
2535 len += ssh1_bignum_length(s->key.modulus);
2536 len += ssh1_bignum_length(s->challenge);
2537 len += 16; /* session id */
2538 len += 4; /* response format */
2539 agentreq = smalloc(4 + len);
2540 PUT_32BIT(agentreq, len);
2541 q = agentreq + 4;
2542 *q++ = SSH1_AGENTC_RSA_CHALLENGE;
2543 PUT_32BIT(q, bignum_bitcount(s->key.modulus));
2544 q += 4;
2545 q += ssh1_write_bignum(q, s->key.exponent);
2546 q += ssh1_write_bignum(q, s->key.modulus);
2547 q += ssh1_write_bignum(q, s->challenge);
2548 memcpy(q, s->session_id, 16);
2549 q += 16;
2550 PUT_32BIT(q, 1); /* response format */
2551 agent_query(agentreq, len + 4, &vret, &retlen);
2552 ret = vret;
2553 sfree(agentreq);
2554 if (ret) {
2555 if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
2556 logevent("Sending Pageant's response");
2557 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2558 PKT_DATA, ret + 5, 16,
2559 PKT_END);
2560 sfree(ret);
2561 crWaitUntil(ispkt);
2562 if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
2563 logevent
2564 ("Pageant's response accepted");
2565 if (flags & FLAG_VERBOSE) {
2566 c_write_str(ssh, "Authenticated using"
2567 " RSA key \"");
2568 c_write(ssh, s->commentp,
2569 s->commentlen);
2570 c_write_str(ssh, "\" from agent\r\n");
2571 }
2572 s->authed = TRUE;
2573 } else
2574 logevent
2575 ("Pageant's response not accepted");
2576 } else {
2577 logevent
2578 ("Pageant failed to answer challenge");
2579 sfree(ret);
2580 }
2581 } else {
2582 logevent("No reply received from Pageant");
2583 }
2584 }
2585 freebn(s->key.exponent);
2586 freebn(s->key.modulus);
2587 freebn(s->challenge);
2588 if (s->authed)
2589 break;
2590 }
2591 }
2592 if (s->authed)
2593 break;
2594 }
2595 if (*cfg.keyfile && !s->tried_publickey)
2596 s->pwpkt_type = SSH1_CMSG_AUTH_RSA;
2597
2598 if (cfg.try_tis_auth &&
2599 (s->supported_auths_mask & (1 << SSH1_AUTH_TIS)) &&
2600 !s->tis_auth_refused) {
2601 s->pwpkt_type = SSH1_CMSG_AUTH_TIS_RESPONSE;
2602 logevent("Requested TIS authentication");
2603 send_packet(ssh, SSH1_CMSG_AUTH_TIS, PKT_END);
2604 crWaitUntil(ispkt);
2605 if (ssh->pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
2606 logevent("TIS authentication declined");
2607 if (flags & FLAG_INTERACTIVE)
2608 c_write_str(ssh, "TIS authentication refused.\r\n");
2609 s->tis_auth_refused = 1;
2610 continue;
2611 } else {
2612 int challengelen = GET_32BIT(ssh->pktin.body);
2613 logevent("Received TIS challenge");
2614 if (challengelen > sizeof(s->prompt) - 1)
2615 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2616 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2617 /* Prompt heuristic comes from OpenSSH */
2618 strncpy(s->prompt + challengelen,
2619 memchr(s->prompt, '\n', challengelen) ?
2620 "": "\r\nResponse: ",
2621 (sizeof s->prompt) - challengelen);
2622 s->prompt[(sizeof s->prompt) - 1] = '\0';
2623 }
2624 }
2625 if (cfg.try_tis_auth &&
2626 (s->supported_auths_mask & (1 << SSH1_AUTH_CCARD)) &&
2627 !s->ccard_auth_refused) {
2628 s->pwpkt_type = SSH1_CMSG_AUTH_CCARD_RESPONSE;
2629 logevent("Requested CryptoCard authentication");
2630 send_packet(ssh, SSH1_CMSG_AUTH_CCARD, PKT_END);
2631 crWaitUntil(ispkt);
2632 if (ssh->pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
2633 logevent("CryptoCard authentication declined");
2634 c_write_str(ssh, "CryptoCard authentication refused.\r\n");
2635 s->ccard_auth_refused = 1;
2636 continue;
2637 } else {
2638 int challengelen = GET_32BIT(ssh->pktin.body);
2639 logevent("Received CryptoCard challenge");
2640 if (challengelen > sizeof(s->prompt) - 1)
2641 challengelen = sizeof(s->prompt) - 1;/* prevent overrun */
2642 memcpy(s->prompt, ssh->pktin.body + 4, challengelen);
2643 strncpy(s->prompt + challengelen,
2644 memchr(s->prompt, '\n', challengelen) ?
2645 "" : "\r\nResponse: ",
2646 sizeof(s->prompt) - challengelen);
2647 s->prompt[sizeof(s->prompt) - 1] = '\0';
2648 }
2649 }
2650 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2651 sprintf(s->prompt, "%.90s@%.90s's password: ",
2652 s->username, ssh->savedhost);
2653 }
2654 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2655 char *comment = NULL;
2656 int type;
2657 char msgbuf[256];
2658 if (flags & FLAG_VERBOSE)
2659 c_write_str(ssh, "Trying public key authentication.\r\n");
2660 logeventf(ssh, "Trying public key \"%s\"", cfg.keyfile);
2661 type = key_type(cfg.keyfile);
2662 if (type != SSH_KEYTYPE_SSH1) {
2663 sprintf(msgbuf, "Key is of wrong type (%s)",
2664 key_type_to_str(type));
2665 logevent(msgbuf);
2666 c_write_str(ssh, msgbuf);
2667 c_write_str(ssh, "\r\n");
2668 s->tried_publickey = 1;
2669 continue;
2670 }
2671 if (!rsakey_encrypted(cfg.keyfile, &comment)) {
2672 if (flags & FLAG_VERBOSE)
2673 c_write_str(ssh, "No passphrase required.\r\n");
2674 goto tryauth;
2675 }
2676 sprintf(s->prompt, "Passphrase for key \"%.100s\": ", comment);
2677 sfree(comment);
2678 }
2679
2680 /*
2681 * Show password prompt, having first obtained it via a TIS
2682 * or CryptoCard exchange if we're doing TIS or CryptoCard
2683 * authentication.
2684 */
2685 if (ssh_get_line) {
2686 if (!ssh_get_line(s->prompt, s->password,
2687 sizeof(s->password), TRUE)) {
2688 /*
2689 * get_line failed to get a password (for example
2690 * because one was supplied on the command line
2691 * which has already failed to work). Terminate.
2692 */
2693 send_packet(ssh, SSH1_MSG_DISCONNECT,
2694 PKT_STR, "No more passwords available to try",
2695 PKT_END);
2696 logevent("Unable to authenticate");
2697 connection_fatal(ssh->frontend, "Unable to authenticate");
2698 ssh->state = SSH_STATE_CLOSED;
2699 crReturn(1);
2700 }
2701 } else {
2702 /* Prompt may have come from server. We've munged it a bit, so
2703 * we know it to be zero-terminated at least once. */
2704 int ret; /* need not be saved over crReturn */
2705 c_write_untrusted(ssh, s->prompt, strlen(s->prompt));
2706 s->pos = 0;
2707
2708 setup_userpass_input(ssh, s->password, sizeof(s->password), 0);
2709 do {
2710 crWaitUntil(!ispkt);
2711 ret = process_userpass_input(ssh, in, inlen);
2712 } while (ret == 0);
2713 if (ret < 0)
2714 cleanup_exit(0);
2715 c_write_str(ssh, "\r\n");
2716 }
2717
2718 tryauth:
2719 if (s->pwpkt_type == SSH1_CMSG_AUTH_RSA) {
2720 /*
2721 * Try public key authentication with the specified
2722 * key file.
2723 */
2724 s->tried_publickey = 1;
2725
2726 {
2727 int ret = loadrsakey(cfg.keyfile, &s->key, s->password);
2728 if (ret == 0) {
2729 c_write_str(ssh, "Couldn't load private key from ");
2730 c_write_str(ssh, cfg.keyfile);
2731 c_write_str(ssh, ".\r\n");
2732 continue; /* go and try password */
2733 }
2734 if (ret == -1) {
2735 c_write_str(ssh, "Wrong passphrase.\r\n");
2736 s->tried_publickey = 0;
2737 continue; /* try again */
2738 }
2739 }
2740
2741 /*
2742 * Send a public key attempt.
2743 */
2744 send_packet(ssh, SSH1_CMSG_AUTH_RSA,
2745 PKT_BIGNUM, s->key.modulus, PKT_END);
2746
2747 crWaitUntil(ispkt);
2748 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2749 c_write_str(ssh, "Server refused our public key.\r\n");
2750 continue; /* go and try password */
2751 }
2752 if (ssh->pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
2753 bombout((ssh,"Bizarre response to offer of public key"));
2754 crReturn(0);
2755 }
2756
2757 {
2758 int i;
2759 unsigned char buffer[32];
2760 Bignum challenge, response;
2761
2762 ssh1_read_bignum(ssh->pktin.body, &challenge);
2763 response = rsadecrypt(challenge, &s->key);
2764 freebn(s->key.private_exponent);/* burn the evidence */
2765
2766 for (i = 0; i < 32; i++) {
2767 buffer[i] = bignum_byte(response, 31 - i);
2768 }
2769
2770 MD5Init(&md5c);
2771 MD5Update(&md5c, buffer, 32);
2772 MD5Update(&md5c, s->session_id, 16);
2773 MD5Final(buffer, &md5c);
2774
2775 send_packet(ssh, SSH1_CMSG_AUTH_RSA_RESPONSE,
2776 PKT_DATA, buffer, 16, PKT_END);
2777
2778 freebn(challenge);
2779 freebn(response);
2780 }
2781
2782 crWaitUntil(ispkt);
2783 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2784 if (flags & FLAG_VERBOSE)
2785 c_write_str(ssh, "Failed to authenticate with"
2786 " our public key.\r\n");
2787 continue; /* go and try password */
2788 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2789 bombout((ssh,"Bizarre response to RSA authentication response"));
2790 crReturn(0);
2791 }
2792
2793 break; /* we're through! */
2794 } else {
2795 if (s->pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
2796 /*
2797 * Defence against traffic analysis: we send a
2798 * whole bunch of packets containing strings of
2799 * different lengths. One of these strings is the
2800 * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
2801 * The others are all random data in
2802 * SSH1_MSG_IGNORE packets. This way a passive
2803 * listener can't tell which is the password, and
2804 * hence can't deduce the password length.
2805 *
2806 * Anybody with a password length greater than 16
2807 * bytes is going to have enough entropy in their
2808 * password that a listener won't find it _that_
2809 * much help to know how long it is. So what we'll
2810 * do is:
2811 *
2812 * - if password length < 16, we send 15 packets
2813 * containing string lengths 1 through 15
2814 *
2815 * - otherwise, we let N be the nearest multiple
2816 * of 8 below the password length, and send 8
2817 * packets containing string lengths N through
2818 * N+7. This won't obscure the order of
2819 * magnitude of the password length, but it will
2820 * introduce a bit of extra uncertainty.
2821 *
2822 * A few servers (the old 1.2.18 through 1.2.22)
2823 * can't deal with SSH1_MSG_IGNORE. For these
2824 * servers, we need an alternative defence. We make
2825 * use of the fact that the password is interpreted
2826 * as a C string: so we can append a NUL, then some
2827 * random data.
2828 *
2829 * One server (a Cisco one) can deal with neither
2830 * SSH1_MSG_IGNORE _nor_ a padded password string.
2831 * For this server we are left with no defences
2832 * against password length sniffing.
2833 */
2834 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE)) {
2835 /*
2836 * The server can deal with SSH1_MSG_IGNORE, so
2837 * we can use the primary defence.
2838 */
2839 int bottom, top, pwlen, i;
2840 char *randomstr;
2841
2842 pwlen = strlen(s->password);
2843 if (pwlen < 16) {
2844 bottom = 0; /* zero length passwords are OK! :-) */
2845 top = 15;
2846 } else {
2847 bottom = pwlen & ~7;
2848 top = bottom + 7;
2849 }
2850
2851 assert(pwlen >= bottom && pwlen <= top);
2852
2853 randomstr = smalloc(top + 1);
2854
2855 for (i = bottom; i <= top; i++) {
2856 if (i == pwlen)
2857 defer_packet(ssh, s->pwpkt_type,
2858 PKT_STR, s->password, PKT_END);
2859 else {
2860 for (j = 0; j < i; j++) {
2861 do {
2862 randomstr[j] = random_byte();
2863 } while (randomstr[j] == '\0');
2864 }
2865 randomstr[i] = '\0';
2866 defer_packet(ssh, SSH1_MSG_IGNORE,
2867 PKT_STR, randomstr, PKT_END);
2868 }
2869 }
2870 logevent("Sending password with camouflage packets");
2871 ssh_pkt_defersend(ssh);
2872 }
2873 else if (!(ssh->remote_bugs & BUG_NEEDS_SSH1_PLAIN_PASSWORD)) {
2874 /*
2875 * The server can't deal with SSH1_MSG_IGNORE
2876 * but can deal with padded passwords, so we
2877 * can use the secondary defence.
2878 */
2879 char string[64];
2880 char *ss;
2881 int len;
2882
2883 len = strlen(s->password);
2884 if (len < sizeof(string)) {
2885 ss = string;
2886 strcpy(string, s->password);
2887 len++; /* cover the zero byte */
2888 while (len < sizeof(string)) {
2889 string[len++] = (char) random_byte();
2890 }
2891 } else {
2892 ss = s->password;
2893 }
2894 logevent("Sending length-padded password");
2895 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2896 PKT_DATA, ss, len, PKT_END);
2897 } else {
2898 /*
2899 * The server has _both_
2900 * BUG_CHOKES_ON_SSH1_IGNORE and
2901 * BUG_NEEDS_SSH1_PLAIN_PASSWORD. There is
2902 * therefore nothing we can do.
2903 */
2904 int len;
2905 len = strlen(s->password);
2906 logevent("Sending unpadded password");
2907 send_packet(ssh, s->pwpkt_type, PKT_INT, len,
2908 PKT_DATA, s->password, len, PKT_END);
2909 }
2910 } else {
2911 send_packet(ssh, s->pwpkt_type, PKT_STR, s->password, PKT_END);
2912 }
2913 }
2914 logevent("Sent password");
2915 memset(s->password, 0, strlen(s->password));
2916 crWaitUntil(ispkt);
2917 if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
2918 if (flags & FLAG_VERBOSE)
2919 c_write_str(ssh, "Access denied\r\n");
2920 logevent("Authentication refused");
2921 } else if (ssh->pktin.type != SSH1_SMSG_SUCCESS) {
2922 bombout((ssh,"Strange packet received, type %d", ssh->pktin.type));
2923 crReturn(0);
2924 }
2925 }
2926
2927 logevent("Authentication successful");
2928
2929 crFinish(1);
2930 }
2931
2932 void sshfwd_close(struct ssh_channel *c)
2933 {
2934 Ssh ssh = c->ssh;
2935
2936 if (c && !c->closes) {
2937 /*
2938 * If the channel's remoteid is -1, we have sent
2939 * CHANNEL_OPEN for this channel, but it hasn't even been
2940 * acknowledged by the server. So we must set a close flag
2941 * on it now, and then when the server acks the channel
2942 * open, we can close it then.
2943 */
2944 if (((int)c->remoteid) != -1) {
2945 if (ssh->version == 1) {
2946 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE, PKT_INT, c->remoteid,
2947 PKT_END);
2948 } else {
2949 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
2950 ssh2_pkt_adduint32(ssh, c->remoteid);
2951 ssh2_pkt_send(ssh);
2952 }
2953 }
2954 c->closes = 1; /* sent MSG_CLOSE */
2955 if (c->type == CHAN_X11) {
2956 c->u.x11.s = NULL;
2957 logevent("Forwarded X11 connection terminated");
2958 } else if (c->type == CHAN_SOCKDATA ||
2959 c->type == CHAN_SOCKDATA_DORMANT) {
2960 c->u.pfd.s = NULL;
2961 logevent("Forwarded port closed");
2962 }
2963 }
2964 }
2965
2966 int sshfwd_write(struct ssh_channel *c, char *buf, int len)
2967 {
2968 Ssh ssh = c->ssh;
2969
2970 if (ssh->version == 1) {
2971 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
2972 PKT_INT, c->remoteid,
2973 PKT_INT, len, PKT_DATA, buf, len, PKT_END);
2974 /*
2975 * In SSH1 we can return 0 here - implying that forwarded
2976 * connections are never individually throttled - because
2977 * the only circumstance that can cause throttling will be
2978 * the whole SSH connection backing up, in which case
2979 * _everything_ will be throttled as a whole.
2980 */
2981 return 0;
2982 } else {
2983 ssh2_add_channel_data(c, buf, len);
2984 return ssh2_try_send(c);
2985 }
2986 }
2987
2988 void sshfwd_unthrottle(struct ssh_channel *c, int bufsize)
2989 {
2990 Ssh ssh = c->ssh;
2991
2992 if (ssh->version == 1) {
2993 if (c->v.v1.throttling && bufsize < SSH1_BUFFER_LIMIT) {
2994 c->v.v1.throttling = 0;
2995 ssh1_throttle(ssh, -1);
2996 }
2997 } else {
2998 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
2999 }
3000 }
3001
3002 static void ssh1_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3003 {
3004 crBegin(ssh->ssh1_protocol_crstate);
3005
3006 random_init();
3007
3008 while (!do_ssh1_login(ssh, in, inlen, ispkt)) {
3009 crReturnV;
3010 }
3011 if (ssh->state == SSH_STATE_CLOSED)
3012 crReturnV;
3013
3014 if (cfg.agentfwd && agent_exists()) {
3015 logevent("Requesting agent forwarding");
3016 send_packet(ssh, SSH1_CMSG_AGENT_REQUEST_FORWARDING, PKT_END);
3017 do {
3018 crReturnV;
3019 } while (!ispkt);
3020 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3021 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3022 bombout((ssh,"Protocol confusion"));
3023 crReturnV;
3024 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3025 logevent("Agent forwarding refused");
3026 } else {
3027 logevent("Agent forwarding enabled");
3028 ssh->agentfwd_enabled = TRUE;
3029 }
3030 }
3031
3032 if (cfg.x11_forward) {
3033 char proto[20], data[64];
3034 logevent("Requesting X11 forwarding");
3035 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
3036 data, sizeof(data));
3037 if (ssh->v1_local_protoflags & SSH1_PROTOFLAG_SCREEN_NUMBER) {
3038 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3039 PKT_STR, proto, PKT_STR, data,
3040 PKT_INT, 0, PKT_END);
3041 } else {
3042 send_packet(ssh, SSH1_CMSG_X11_REQUEST_FORWARDING,
3043 PKT_STR, proto, PKT_STR, data, PKT_END);
3044 }
3045 do {
3046 crReturnV;
3047 } while (!ispkt);
3048 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3049 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3050 bombout((ssh,"Protocol confusion"));
3051 crReturnV;
3052 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3053 logevent("X11 forwarding refused");
3054 } else {
3055 logevent("X11 forwarding enabled");
3056 ssh->X11_fwd_enabled = TRUE;
3057 }
3058 }
3059
3060 {
3061 char type;
3062 int n;
3063 int sport,dport,sserv,dserv;
3064 char sports[256], dports[256], saddr[256], host[256];
3065
3066 ssh->rportfwds = newtree234(ssh_rportcmp_ssh1);
3067 /* Add port forwardings. */
3068 ssh->portfwd_strptr = cfg.portfwd;
3069 while (*ssh->portfwd_strptr) {
3070 type = *ssh->portfwd_strptr++;
3071 saddr[0] = '\0';
3072 n = 0;
3073 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
3074 if (*ssh->portfwd_strptr == ':') {
3075 /*
3076 * We've seen a colon in the middle of the
3077 * source port number. This means that
3078 * everything we've seen until now is the
3079 * source _address_, so we'll move it into
3080 * saddr and start sports from the beginning
3081 * again.
3082 */
3083 ssh->portfwd_strptr++;
3084 sports[n] = '\0';
3085 strcpy(saddr, sports);
3086 n = 0;
3087 }
3088 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
3089 }
3090 sports[n] = 0;
3091 if (*ssh->portfwd_strptr == '\t')
3092 ssh->portfwd_strptr++;
3093 n = 0;
3094 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
3095 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
3096 }
3097 host[n] = 0;
3098 if (*ssh->portfwd_strptr == ':')
3099 ssh->portfwd_strptr++;
3100 n = 0;
3101 while (*ssh->portfwd_strptr) {
3102 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
3103 }
3104 dports[n] = 0;
3105 ssh->portfwd_strptr++;
3106 dport = atoi(dports);
3107 dserv = 0;
3108 if (dport == 0) {
3109 dserv = 1;
3110 dport = net_service_lookup(dports);
3111 if (!dport) {
3112 logeventf(ssh, "Service lookup failed for"
3113 " destination port \"%s\"", dports);
3114 }
3115 }
3116 sport = atoi(sports);
3117 sserv = 0;
3118 if (sport == 0) {
3119 sserv = 1;
3120 sport = net_service_lookup(sports);
3121 if (!sport) {
3122 logeventf(ssh, "Service lookup failed for source"
3123 " port \"%s\"", sports);
3124 }
3125 }
3126 if (sport && dport) {
3127 if (type == 'L') {
3128 pfd_addforward(host, dport, *saddr ? saddr : NULL,
3129 sport, ssh);
3130 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
3131 " forwarding to %s:%.*s%.*s%d%.*s",
3132 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
3133 (int)(*saddr?1:0), ":",
3134 (int)(sserv ? strlen(sports) : 0), sports,
3135 sserv, "(", sport, sserv, ")",
3136 host,
3137 (int)(dserv ? strlen(dports) : 0), dports,
3138 dserv, "(", dport, dserv, ")");
3139 } else {
3140 struct ssh_rportfwd *pf;
3141 pf = smalloc(sizeof(*pf));
3142 strcpy(pf->dhost, host);
3143 pf->dport = dport;
3144 if (saddr) {
3145 logeventf(ssh,
3146 "SSH1 cannot handle source address spec \"%s:%d\"; ignoring",
3147 saddr, sport);
3148 }
3149 if (add234(ssh->rportfwds, pf) != pf) {
3150 logeventf(ssh,
3151 "Duplicate remote port forwarding to %s:%d",
3152 host, dport);
3153 sfree(pf);
3154 } else {
3155 logeventf(ssh, "Requesting remote port %.*s%.*s%d%.*s"
3156 " forward to %s:%.*s%.*s%d%.*s",
3157 (int)(sserv ? strlen(sports) : 0), sports,
3158 sserv, "(", sport, sserv, ")",
3159 host,
3160 (int)(dserv ? strlen(dports) : 0), dports,
3161 dserv, "(", dport, dserv, ")");
3162 send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
3163 PKT_INT, sport,
3164 PKT_STR, host,
3165 PKT_INT, dport,
3166 PKT_END);
3167 do {
3168 crReturnV;
3169 } while (!ispkt);
3170 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3171 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3172 bombout((ssh,"Protocol confusion"));
3173 crReturnV;
3174 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3175 c_write_str(ssh, "Server refused port"
3176 " forwarding\r\n");
3177 }
3178 logevent("Remote port forwarding enabled");
3179 }
3180 }
3181 }
3182 }
3183 }
3184
3185 if (!cfg.nopty) {
3186 send_packet(ssh, SSH1_CMSG_REQUEST_PTY,
3187 PKT_STR, cfg.termtype,
3188 PKT_INT, ssh->term_height,
3189 PKT_INT, ssh->term_width,
3190 PKT_INT, 0, PKT_INT, 0, PKT_CHAR, 0, PKT_END);
3191 ssh->state = SSH_STATE_INTERMED;
3192 do {
3193 crReturnV;
3194 } while (!ispkt);
3195 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3196 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3197 bombout((ssh,"Protocol confusion"));
3198 crReturnV;
3199 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3200 c_write_str(ssh, "Server refused to allocate pty\r\n");
3201 ssh->editing = ssh->echoing = 1;
3202 }
3203 logevent("Allocated pty");
3204 } else {
3205 ssh->editing = ssh->echoing = 1;
3206 }
3207
3208 if (cfg.compression) {
3209 send_packet(ssh, SSH1_CMSG_REQUEST_COMPRESSION, PKT_INT, 6, PKT_END);
3210 do {
3211 crReturnV;
3212 } while (!ispkt);
3213 if (ssh->pktin.type != SSH1_SMSG_SUCCESS
3214 && ssh->pktin.type != SSH1_SMSG_FAILURE) {
3215 bombout((ssh,"Protocol confusion"));
3216 crReturnV;
3217 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3218 c_write_str(ssh, "Server refused to compress\r\n");
3219 }
3220 logevent("Started compression");
3221 ssh->v1_compressing = TRUE;
3222 ssh->cs_comp_ctx = zlib_compress_init();
3223 logevent("Initialised zlib (RFC1950) compression");
3224 ssh->sc_comp_ctx = zlib_decompress_init();
3225 logevent("Initialised zlib (RFC1950) decompression");
3226 }
3227
3228 /*
3229 * Start the shell or command.
3230 *
3231 * Special case: if the first-choice command is an SSH2
3232 * subsystem (hence not usable here) and the second choice
3233 * exists, we fall straight back to that.
3234 */
3235 {
3236 char *cmd = cfg.remote_cmd_ptr;
3237
3238 if (cfg.ssh_subsys && cfg.remote_cmd_ptr2) {
3239 cmd = cfg.remote_cmd_ptr2;
3240 ssh->fallback_cmd = TRUE;
3241 }
3242 if (*cmd)
3243 send_packet(ssh, SSH1_CMSG_EXEC_CMD, PKT_STR, cmd, PKT_END);
3244 else
3245 send_packet(ssh, SSH1_CMSG_EXEC_SHELL, PKT_END);
3246 logevent("Started session");
3247 }
3248
3249 ssh->state = SSH_STATE_SESSION;
3250 if (ssh->size_needed)
3251 ssh_size(ssh, ssh->term_width, ssh->term_height);
3252 if (ssh->eof_needed)
3253 ssh_special(ssh, TS_EOF);
3254
3255 if (ssh->ldisc)
3256 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
3257 ssh->send_ok = 1;
3258 ssh->channels = newtree234(ssh_channelcmp);
3259 while (1) {
3260 crReturnV;
3261 if (ispkt) {
3262 if (ssh->pktin.type == SSH1_SMSG_STDOUT_DATA ||
3263 ssh->pktin.type == SSH1_SMSG_STDERR_DATA) {
3264 long len = GET_32BIT(ssh->pktin.body);
3265 int bufsize =
3266 from_backend(ssh->frontend,
3267 ssh->pktin.type == SSH1_SMSG_STDERR_DATA,
3268 ssh->pktin.body + 4, len);
3269 if (!ssh->v1_stdout_throttling && bufsize > SSH1_BUFFER_LIMIT) {
3270 ssh->v1_stdout_throttling = 1;
3271 ssh1_throttle(ssh, +1);
3272 }
3273 } else if (ssh->pktin.type == SSH1_MSG_DISCONNECT) {
3274 ssh->state = SSH_STATE_CLOSED;
3275 logevent("Received disconnect request");
3276 crReturnV;
3277 } else if (ssh->pktin.type == SSH1_SMSG_X11_OPEN) {
3278 /* Remote side is trying to open a channel to talk to our
3279 * X-Server. Give them back a local channel number. */
3280 struct ssh_channel *c;
3281
3282 logevent("Received X11 connect request");
3283 /* Refuse if X11 forwarding is disabled. */
3284 if (!ssh->X11_fwd_enabled) {
3285 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3286 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3287 logevent("Rejected X11 connect request");
3288 } else {
3289 c = smalloc(sizeof(struct ssh_channel));
3290 c->ssh = ssh;
3291
3292 if (x11_init(&c->u.x11.s, cfg.x11_display, c,
3293 ssh->x11auth) != NULL) {
3294 logevent("opening X11 forward connection failed");
3295 sfree(c);
3296 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3297 PKT_INT, GET_32BIT(ssh->pktin.body),
3298 PKT_END);
3299 } else {
3300 logevent
3301 ("opening X11 forward connection succeeded");
3302 c->remoteid = GET_32BIT(ssh->pktin.body);
3303 c->localid = alloc_channel_id(ssh);
3304 c->closes = 0;
3305 c->v.v1.throttling = 0;
3306 c->type = CHAN_X11; /* identify channel type */
3307 add234(ssh->channels, c);
3308 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3309 PKT_INT, c->remoteid, PKT_INT,
3310 c->localid, PKT_END);
3311 logevent("Opened X11 forward channel");
3312 }
3313 }
3314 } else if (ssh->pktin.type == SSH1_SMSG_AGENT_OPEN) {
3315 /* Remote side is trying to open a channel to talk to our
3316 * agent. Give them back a local channel number. */
3317 struct ssh_channel *c;
3318
3319 /* Refuse if agent forwarding is disabled. */
3320 if (!ssh->agentfwd_enabled) {
3321 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3322 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3323 } else {
3324 c = smalloc(sizeof(struct ssh_channel));
3325 c->ssh = ssh;
3326 c->remoteid = GET_32BIT(ssh->pktin.body);
3327 c->localid = alloc_channel_id(ssh);
3328 c->closes = 0;
3329 c->v.v1.throttling = 0;
3330 c->type = CHAN_AGENT; /* identify channel type */
3331 c->u.a.lensofar = 0;
3332 add234(ssh->channels, c);
3333 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3334 PKT_INT, c->remoteid, PKT_INT, c->localid,
3335 PKT_END);
3336 }
3337 } else if (ssh->pktin.type == SSH1_MSG_PORT_OPEN) {
3338 /* Remote side is trying to open a channel to talk to a
3339 * forwarded port. Give them back a local channel number. */
3340 struct ssh_channel *c;
3341 struct ssh_rportfwd pf;
3342 int hostsize, port;
3343 char host[256], buf[1024];
3344 char *p, *h, *e;
3345 c = smalloc(sizeof(struct ssh_channel));
3346 c->ssh = ssh;
3347
3348 hostsize = GET_32BIT(ssh->pktin.body+4);
3349 for(h = host, p = ssh->pktin.body+8; hostsize != 0; hostsize--) {
3350 if (h+1 < host+sizeof(host))
3351 *h++ = *p;
3352 p++;
3353 }
3354 *h = 0;
3355 port = GET_32BIT(p);
3356
3357 strcpy(pf.dhost, host);
3358 pf.dport = port;
3359
3360 if (find234(ssh->rportfwds, &pf, NULL) == NULL) {
3361 sprintf(buf, "Rejected remote port open request for %s:%d",
3362 host, port);
3363 logevent(buf);
3364 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3365 PKT_INT, GET_32BIT(ssh->pktin.body), PKT_END);
3366 } else {
3367 sprintf(buf, "Received remote port open request for %s:%d",
3368 host, port);
3369 logevent(buf);
3370 e = pfd_newconnect(&c->u.pfd.s, host, port, c);
3371 if (e != NULL) {
3372 char buf[256];
3373 sprintf(buf, "Port open failed: %s", e);
3374 logevent(buf);
3375 sfree(c);
3376 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_FAILURE,
3377 PKT_INT, GET_32BIT(ssh->pktin.body),
3378 PKT_END);
3379 } else {
3380 c->remoteid = GET_32BIT(ssh->pktin.body);
3381 c->localid = alloc_channel_id(ssh);
3382 c->closes = 0;
3383 c->v.v1.throttling = 0;
3384 c->type = CHAN_SOCKDATA; /* identify channel type */
3385 add234(ssh->channels, c);
3386 send_packet(ssh, SSH1_MSG_CHANNEL_OPEN_CONFIRMATION,
3387 PKT_INT, c->remoteid, PKT_INT,
3388 c->localid, PKT_END);
3389 logevent("Forwarded port opened successfully");
3390 }
3391 }
3392
3393 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_CONFIRMATION) {
3394 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3395 unsigned int localid = GET_32BIT(ssh->pktin.body+4);
3396 struct ssh_channel *c;
3397
3398 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3399 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3400 c->remoteid = localid;
3401 c->type = CHAN_SOCKDATA;
3402 c->v.v1.throttling = 0;
3403 pfd_confirm(c->u.pfd.s);
3404 }
3405
3406 if (c && c->closes) {
3407 /*
3408 * We have a pending close on this channel,
3409 * which we decided on before the server acked
3410 * the channel open. So now we know the
3411 * remoteid, we can close it again.
3412 */
3413 send_packet(ssh, SSH1_MSG_CHANNEL_CLOSE,
3414 PKT_INT, c->remoteid, PKT_END);
3415 }
3416
3417 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_OPEN_FAILURE) {
3418 unsigned int remoteid = GET_32BIT(ssh->pktin.body);
3419 struct ssh_channel *c;
3420
3421 c = find234(ssh->channels, &remoteid, ssh_channelfind);
3422 if (c && c->type == CHAN_SOCKDATA_DORMANT) {
3423 logevent("Forwarded connection refused by server");
3424 pfd_close(c->u.pfd.s);
3425 del234(ssh->channels, c);
3426 sfree(c);
3427 }
3428
3429 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ||
3430 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE_CONFIRMATION) {
3431 /* Remote side closes a channel. */
3432 unsigned i = GET_32BIT(ssh->pktin.body);
3433 struct ssh_channel *c;
3434 c = find234(ssh->channels, &i, ssh_channelfind);
3435 if (c && ((int)c->remoteid) != -1) {
3436 int closetype;
3437 closetype =
3438 (ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? 1 : 2);
3439
3440 if ((c->closes == 0) && (c->type == CHAN_X11)) {
3441 logevent("Forwarded X11 connection terminated");
3442 assert(c->u.x11.s != NULL);
3443 x11_close(c->u.x11.s);
3444 c->u.x11.s = NULL;
3445 }
3446 if ((c->closes == 0) && (c->type == CHAN_SOCKDATA)) {
3447 logevent("Forwarded port closed");
3448 assert(c->u.pfd.s != NULL);
3449 pfd_close(c->u.pfd.s);
3450 c->u.pfd.s = NULL;
3451 }
3452
3453 c->closes |= (closetype << 2); /* seen this message */
3454 if (!(c->closes & closetype)) {
3455 send_packet(ssh, ssh->pktin.type, PKT_INT, c->remoteid,
3456 PKT_END);
3457 c->closes |= closetype; /* sent it too */
3458 }
3459
3460 if (c->closes == 15) {
3461 del234(ssh->channels, c);
3462 sfree(c);
3463 }
3464 } else {
3465 bombout((ssh,"Received CHANNEL_CLOSE%s for %s channel %d\n",
3466 ssh->pktin.type == SSH1_MSG_CHANNEL_CLOSE ? "" :
3467 "_CONFIRMATION", c ? "half-open" : "nonexistent",
3468 i));
3469 }
3470 } else if (ssh->pktin.type == SSH1_MSG_CHANNEL_DATA) {
3471 /* Data sent down one of our channels. */
3472 int i = GET_32BIT(ssh->pktin.body);
3473 int len = GET_32BIT(ssh->pktin.body + 4);
3474 unsigned char *p = ssh->pktin.body + 8;
3475 struct ssh_channel *c;
3476 c = find234(ssh->channels, &i, ssh_channelfind);
3477 if (c) {
3478 int bufsize;
3479 switch (c->type) {
3480 case CHAN_X11:
3481 bufsize = x11_send(c->u.x11.s, p, len);
3482 break;
3483 case CHAN_SOCKDATA:
3484 bufsize = pfd_send(c->u.pfd.s, p, len);
3485 break;
3486 case CHAN_AGENT:
3487 /* Data for an agent message. Buffer it. */
3488 while (len > 0) {
3489 if (c->u.a.lensofar < 4) {
3490 int l = min(4 - c->u.a.lensofar, len);
3491 memcpy(c->u.a.msglen + 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 == 4) {
3498 c->u.a.totallen =
3499 4 + GET_32BIT(c->u.a.msglen);
3500 c->u.a.message = smalloc(c->u.a.totallen);
3501 memcpy(c->u.a.message, c->u.a.msglen, 4);
3502 }
3503 if (c->u.a.lensofar >= 4 && len > 0) {
3504 int l =
3505 min(c->u.a.totallen - c->u.a.lensofar,
3506 len);
3507 memcpy(c->u.a.message + c->u.a.lensofar, p,
3508 l);
3509 p += l;
3510 len -= l;
3511 c->u.a.lensofar += l;
3512 }
3513 if (c->u.a.lensofar == c->u.a.totallen) {
3514 void *reply, *sentreply;
3515 int replylen;
3516 agent_query(c->u.a.message,
3517 c->u.a.totallen, &reply,
3518 &replylen);
3519 if (reply)
3520 sentreply = reply;
3521 else {
3522 /* Fake SSH_AGENT_FAILURE. */
3523 sentreply = "\0\0\0\1\5";
3524 replylen = 5;
3525 }
3526 send_packet(ssh, SSH1_MSG_CHANNEL_DATA,
3527 PKT_INT, c->remoteid,
3528 PKT_INT, replylen,
3529 PKT_DATA, sentreply, replylen,
3530 PKT_END);
3531 if (reply)
3532 sfree(reply);
3533 sfree(c->u.a.message);
3534 c->u.a.lensofar = 0;
3535 }
3536 }
3537 bufsize = 0; /* agent channels never back up */
3538 break;
3539 }
3540 if (!c->v.v1.throttling && bufsize > SSH1_BUFFER_LIMIT) {
3541 c->v.v1.throttling = 1;
3542 ssh1_throttle(ssh, +1);
3543 }
3544 }
3545 } else if (ssh->pktin.type == SSH1_SMSG_SUCCESS) {
3546 /* may be from EXEC_SHELL on some servers */
3547 } else if (ssh->pktin.type == SSH1_SMSG_FAILURE) {
3548 /* may be from EXEC_SHELL on some servers
3549 * if no pty is available or in other odd cases. Ignore */
3550 } else if (ssh->pktin.type == SSH1_SMSG_EXIT_STATUS) {
3551 char buf[100];
3552 ssh->exitcode = GET_32BIT(ssh->pktin.body);
3553 sprintf(buf, "Server sent command exit status %d",
3554 ssh->exitcode);
3555 logevent(buf);
3556 send_packet(ssh, SSH1_CMSG_EXIT_CONFIRMATION, PKT_END);
3557 /*
3558 * In case `helpful' firewalls or proxies tack
3559 * extra human-readable text on the end of the
3560 * session which we might mistake for another
3561 * encrypted packet, we close the session once
3562 * we've sent EXIT_CONFIRMATION.
3563 */
3564 ssh->state = SSH_STATE_CLOSED;
3565 crReturnV;
3566 } else {
3567 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
3568 crReturnV;
3569 }
3570 } else {
3571 while (inlen > 0) {
3572 int len = min(inlen, 512);
3573 send_packet(ssh, SSH1_CMSG_STDIN_DATA,
3574 PKT_INT, len, PKT_DATA, in, len, PKT_END);
3575 in += len;
3576 inlen -= len;
3577 }
3578 }
3579 }
3580
3581 crFinishV;
3582 }
3583
3584 /*
3585 * Utility routine for decoding comma-separated strings in KEXINIT.
3586 */
3587 static int in_commasep_string(char *needle, char *haystack, int haylen)
3588 {
3589 int needlen;
3590 if (!needle || !haystack) /* protect against null pointers */
3591 return 0;
3592 needlen = strlen(needle);
3593 while (1) {
3594 /*
3595 * Is it at the start of the string?
3596 */
3597 if (haylen >= needlen && /* haystack is long enough */
3598 !memcmp(needle, haystack, needlen) && /* initial match */
3599 (haylen == needlen || haystack[needlen] == ',')
3600 /* either , or EOS follows */
3601 )
3602 return 1;
3603 /*
3604 * If not, search for the next comma and resume after that.
3605 * If no comma found, terminate.
3606 */
3607 while (haylen > 0 && *haystack != ',')
3608 haylen--, haystack++;
3609 if (haylen == 0)
3610 return 0;
3611 haylen--, haystack++; /* skip over comma itself */
3612 }
3613 }
3614
3615 /*
3616 * SSH2 key creation method.
3617 */
3618 static void ssh2_mkkey(Ssh ssh, Bignum K, char *H, char *sessid, char chr,
3619 char *keyspace)
3620 {
3621 SHA_State s;
3622 /* First 20 bytes. */
3623 SHA_Init(&s);
3624 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3625 sha_mpint(&s, K);
3626 SHA_Bytes(&s, H, 20);
3627 SHA_Bytes(&s, &chr, 1);
3628 SHA_Bytes(&s, sessid, 20);
3629 SHA_Final(&s, keyspace);
3630 /* Next 20 bytes. */
3631 SHA_Init(&s);
3632 if (!(ssh->remote_bugs & BUG_SSH2_DERIVEKEY))
3633 sha_mpint(&s, K);
3634 SHA_Bytes(&s, H, 20);
3635 SHA_Bytes(&s, keyspace, 20);
3636 SHA_Final(&s, keyspace + 20);
3637 }
3638
3639 /*
3640 * Handle the SSH2 transport layer.
3641 */
3642 static int do_ssh2_transport(Ssh ssh, unsigned char *in, int inlen, int ispkt)
3643 {
3644 struct do_ssh2_transport_state {
3645 int nbits, pbits, warn;
3646 Bignum p, g, e, f, K;
3647 int kex_init_value, kex_reply_value;
3648 const struct ssh_mac **maclist;
3649 int nmacs;
3650 const struct ssh2_cipher *cscipher_tobe;
3651 const struct ssh2_cipher *sccipher_tobe;
3652 const struct ssh_mac *csmac_tobe;
3653 const struct ssh_mac *scmac_tobe;
3654 const struct ssh_compress *cscomp_tobe;
3655 const struct ssh_compress *sccomp_tobe;
3656 char *hostkeydata, *sigdata, *keystr, *fingerprint;
3657 int hostkeylen, siglen;
3658 void *hkey; /* actual host key */
3659 unsigned char exchange_hash[20];
3660 int n_preferred_ciphers;
3661 const struct ssh2_ciphers *preferred_ciphers[CIPHER_MAX];
3662 const struct ssh_compress *preferred_comp;
3663 int first_kex;
3664 };
3665 crState(do_ssh2_transport_state);
3666
3667 crBegin(ssh->do_ssh2_transport_crstate);
3668
3669 s->cscipher_tobe = s->sccipher_tobe = NULL;
3670 s->csmac_tobe = s->scmac_tobe = NULL;
3671 s->cscomp_tobe = s->sccomp_tobe = NULL;
3672
3673 random_init();
3674 s->first_kex = 1;
3675
3676 {
3677 int i;
3678 /*
3679 * Set up the preferred ciphers. (NULL => warn below here)
3680 */
3681 s->n_preferred_ciphers = 0;
3682 for (i = 0; i < CIPHER_MAX; i++) {
3683 switch (cfg.ssh_cipherlist[i]) {
3684 case CIPHER_BLOWFISH:
3685 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_blowfish;
3686 break;
3687 case CIPHER_DES:
3688 if (cfg.ssh2_des_cbc) {
3689 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_des;
3690 }
3691 break;
3692 case CIPHER_3DES:
3693 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_3des;
3694 break;
3695 case CIPHER_AES:
3696 s->preferred_ciphers[s->n_preferred_ciphers++] = &ssh2_aes;
3697 break;
3698 case CIPHER_WARN:
3699 /* Flag for later. Don't bother if it's the last in
3700 * the list. */
3701 if (i < CIPHER_MAX - 1) {
3702 s->preferred_ciphers[s->n_preferred_ciphers++] = NULL;
3703 }
3704 break;
3705 }
3706 }
3707 }
3708
3709 /*
3710 * Set up preferred compression.
3711 */
3712 if (cfg.compression)
3713 s->preferred_comp = &ssh_zlib;
3714 else
3715 s->preferred_comp = &ssh_comp_none;
3716
3717 /*
3718 * Be prepared to work around the buggy MAC problem.
3719 */
3720 if (ssh->remote_bugs & BUG_SSH2_HMAC)
3721 s->maclist = buggymacs, s->nmacs = lenof(buggymacs);
3722 else
3723 s->maclist = macs, s->nmacs = lenof(macs);
3724
3725 begin_key_exchange:
3726 {
3727 int i, j, cipherstr_started;
3728
3729 /*
3730 * Construct and send our key exchange packet.
3731 */
3732 ssh2_pkt_init(ssh, SSH2_MSG_KEXINIT);
3733 for (i = 0; i < 16; i++)
3734 ssh2_pkt_addbyte(ssh, (unsigned char) random_byte());
3735 /* List key exchange algorithms. */
3736 ssh2_pkt_addstring_start(ssh);
3737 for (i = 0; i < lenof(kex_algs); i++) {
3738 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3739 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3740 continue;
3741 ssh2_pkt_addstring_str(ssh, kex_algs[i]->name);
3742 if (i < lenof(kex_algs) - 1)
3743 ssh2_pkt_addstring_str(ssh, ",");
3744 }
3745 /* List server host key algorithms. */
3746 ssh2_pkt_addstring_start(ssh);
3747 for (i = 0; i < lenof(hostkey_algs); i++) {
3748 ssh2_pkt_addstring_str(ssh, hostkey_algs[i]->name);
3749 if (i < lenof(hostkey_algs) - 1)
3750 ssh2_pkt_addstring_str(ssh, ",");
3751 }
3752 /* List client->server encryption algorithms. */
3753 ssh2_pkt_addstring_start(ssh);
3754 cipherstr_started = 0;
3755 for (i = 0; i < s->n_preferred_ciphers; i++) {
3756 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3757 if (!c) continue; /* warning flag */
3758 for (j = 0; j < c->nciphers; j++) {
3759 if (cipherstr_started)
3760 ssh2_pkt_addstring_str(ssh, ",");
3761 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3762 cipherstr_started = 1;
3763 }
3764 }
3765 /* List server->client encryption algorithms. */
3766 ssh2_pkt_addstring_start(ssh);
3767 cipherstr_started = 0;
3768 for (i = 0; i < s->n_preferred_ciphers; i++) {
3769 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3770 if (!c) continue; /* warning flag */
3771 for (j = 0; j < c->nciphers; j++) {
3772 if (cipherstr_started)
3773 ssh2_pkt_addstring_str(ssh, ",");
3774 ssh2_pkt_addstring_str(ssh, c->list[j]->name);
3775 cipherstr_started = 1;
3776 }
3777 }
3778 /* List client->server MAC algorithms. */
3779 ssh2_pkt_addstring_start(ssh);
3780 for (i = 0; i < s->nmacs; i++) {
3781 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3782 if (i < s->nmacs - 1)
3783 ssh2_pkt_addstring_str(ssh, ",");
3784 }
3785 /* List server->client MAC algorithms. */
3786 ssh2_pkt_addstring_start(ssh);
3787 for (i = 0; i < s->nmacs; i++) {
3788 ssh2_pkt_addstring_str(ssh, s->maclist[i]->name);
3789 if (i < s->nmacs - 1)
3790 ssh2_pkt_addstring_str(ssh, ",");
3791 }
3792 /* List client->server compression algorithms. */
3793 ssh2_pkt_addstring_start(ssh);
3794 for (i = 0; i < lenof(compressions) + 1; i++) {
3795 const struct ssh_compress *c =
3796 i == 0 ? s->preferred_comp : compressions[i - 1];
3797 ssh2_pkt_addstring_str(ssh, c->name);
3798 if (i < lenof(compressions))
3799 ssh2_pkt_addstring_str(ssh, ",");
3800 }
3801 /* List server->client compression algorithms. */
3802 ssh2_pkt_addstring_start(ssh);
3803 for (i = 0; i < lenof(compressions) + 1; i++) {
3804 const struct ssh_compress *c =
3805 i == 0 ? s->preferred_comp : compressions[i - 1];
3806 ssh2_pkt_addstring_str(ssh, c->name);
3807 if (i < lenof(compressions))
3808 ssh2_pkt_addstring_str(ssh, ",");
3809 }
3810 /* List client->server languages. Empty list. */
3811 ssh2_pkt_addstring_start(ssh);
3812 /* List server->client languages. Empty list. */
3813 ssh2_pkt_addstring_start(ssh);
3814 /* First KEX packet does _not_ follow, because we're not that brave. */
3815 ssh2_pkt_addbool(ssh, FALSE);
3816 /* Reserved. */
3817 ssh2_pkt_adduint32(ssh, 0);
3818 }
3819
3820 ssh->exhash = ssh->exhashbase;
3821 sha_string(&ssh->exhash, ssh->pktout.data + 5, ssh->pktout.length - 5);
3822
3823 ssh2_pkt_send(ssh);
3824
3825 if (!ispkt)
3826 crWaitUntil(ispkt);
3827 if (ssh->pktin.length > 5)
3828 sha_string(&ssh->exhash, ssh->pktin.data + 5, ssh->pktin.length - 5);
3829
3830 /*
3831 * Now examine the other side's KEXINIT to see what we're up
3832 * to.
3833 */
3834 {
3835 char *str;
3836 int i, j, len;
3837
3838 if (ssh->pktin.type != SSH2_MSG_KEXINIT) {
3839 bombout((ssh,"expected key exchange packet from server"));
3840 crReturn(0);
3841 }
3842 ssh->kex = NULL;
3843 ssh->hostkey = NULL;
3844 s->cscipher_tobe = NULL;
3845 s->sccipher_tobe = NULL;
3846 s->csmac_tobe = NULL;
3847 s->scmac_tobe = NULL;
3848 s->cscomp_tobe = NULL;
3849 s->sccomp_tobe = NULL;
3850 ssh->pktin.savedpos += 16; /* skip garbage cookie */
3851 ssh2_pkt_getstring(ssh, &str, &len); /* key exchange algorithms */
3852 for (i = 0; i < lenof(kex_algs); i++) {
3853 if (kex_algs[i] == &ssh_diffiehellman_gex &&
3854 (ssh->remote_bugs & BUG_SSH2_DH_GEX))
3855 continue;
3856 if (in_commasep_string(kex_algs[i]->name, str, len)) {
3857 ssh->kex = kex_algs[i];
3858 break;
3859 }
3860 }
3861 ssh2_pkt_getstring(ssh, &str, &len); /* host key algorithms */
3862 for (i = 0; i < lenof(hostkey_algs); i++) {
3863 if (in_commasep_string(hostkey_algs[i]->name, str, len)) {
3864 ssh->hostkey = hostkey_algs[i];
3865 break;
3866 }
3867 }
3868 ssh2_pkt_getstring(ssh, &str, &len); /* client->server cipher */
3869 s->warn = 0;
3870 for (i = 0; i < s->n_preferred_ciphers; i++) {
3871 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3872 if (!c) {
3873 s->warn = 1;
3874 } else {
3875 for (j = 0; j < c->nciphers; j++) {
3876 if (in_commasep_string(c->list[j]->name, str, len)) {
3877 s->cscipher_tobe = c->list[j];
3878 break;
3879 }
3880 }
3881 }
3882 if (s->cscipher_tobe) {
3883 if (s->warn)
3884 askcipher(ssh->frontend, s->cscipher_tobe->name, 1);
3885 break;
3886 }
3887 }
3888 if (!s->cscipher_tobe) {
3889 bombout((ssh,"Couldn't agree a client-to-server cipher (available: %s)",
3890 str ? str : "(null)"));
3891 crReturn(0);
3892 }
3893
3894 ssh2_pkt_getstring(ssh, &str, &len); /* server->client cipher */
3895 s->warn = 0;
3896 for (i = 0; i < s->n_preferred_ciphers; i++) {
3897 const struct ssh2_ciphers *c = s->preferred_ciphers[i];
3898 if (!c) {
3899 s->warn = 1;
3900 } else {
3901 for (j = 0; j < c->nciphers; j++) {
3902 if (in_commasep_string(c->list[j]->name, str, len)) {
3903 s->sccipher_tobe = c->list[j];
3904 break;
3905 }
3906 }
3907 }
3908 if (s->sccipher_tobe) {
3909 if (s->warn)
3910 askcipher(ssh->frontend, s->sccipher_tobe->name, 2);
3911 break;
3912 }
3913 }
3914 if (!s->sccipher_tobe) {
3915 bombout((ssh,"Couldn't agree a server-to-client cipher (available: %s)",
3916 str ? str : "(null)"));
3917 crReturn(0);
3918 }
3919
3920 ssh2_pkt_getstring(ssh, &str, &len); /* client->server mac */
3921 for (i = 0; i < s->nmacs; i++) {
3922 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3923 s->csmac_tobe = s->maclist[i];
3924 break;
3925 }
3926 }
3927 ssh2_pkt_getstring(ssh, &str, &len); /* server->client mac */
3928 for (i = 0; i < s->nmacs; i++) {
3929 if (in_commasep_string(s->maclist[i]->name, str, len)) {
3930 s->scmac_tobe = s->maclist[i];
3931 break;
3932 }
3933 }
3934 ssh2_pkt_getstring(ssh, &str, &len); /* client->server compression */
3935 for (i = 0; i < lenof(compressions) + 1; i++) {
3936 const struct ssh_compress *c =
3937 i == 0 ? s->preferred_comp : compressions[i - 1];
3938 if (in_commasep_string(c->name, str, len)) {
3939 s->cscomp_tobe = c;
3940 break;
3941 }
3942 }
3943 ssh2_pkt_getstring(ssh, &str, &len); /* server->client compression */
3944 for (i = 0; i < lenof(compressions) + 1; i++) {
3945 const struct ssh_compress *c =
3946 i == 0 ? s->preferred_comp : compressions[i - 1];
3947 if (in_commasep_string(c->name, str, len)) {
3948 s->sccomp_tobe = c;
3949 break;
3950 }
3951 }
3952 }
3953
3954 /*
3955 * Work out the number of bits of key we will need from the key
3956 * exchange. We start with the maximum key length of either
3957 * cipher...
3958 */
3959 {
3960 int csbits, scbits;
3961
3962 csbits = s->cscipher_tobe->keylen;
3963 scbits = s->sccipher_tobe->keylen;
3964 s->nbits = (csbits > scbits ? csbits : scbits);
3965 }
3966 /* The keys only have 160-bit entropy, since they're based on
3967 * a SHA-1 hash. So cap the key size at 160 bits. */
3968 if (s->nbits > 160)
3969 s->nbits = 160;
3970
3971 /*
3972 * If we're doing Diffie-Hellman group exchange, start by
3973 * requesting a group.
3974 */
3975 if (ssh->kex == &ssh_diffiehellman_gex) {
3976 logevent("Doing Diffie-Hellman group exchange");
3977 ssh->pkt_ctx |= SSH2_PKTCTX_DHGEX;
3978 /*
3979 * Work out how big a DH group we will need to allow that
3980 * much data.
3981 */
3982 s->pbits = 512 << ((s->nbits - 1) / 64);
3983 ssh2_pkt_init(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST);
3984 ssh2_pkt_adduint32(ssh, s->pbits);
3985 ssh2_pkt_send(ssh);
3986
3987 crWaitUntil(ispkt);
3988 if (ssh->pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
3989 bombout((ssh,"expected key exchange group packet from server"));
3990 crReturn(0);
3991 }
3992 s->p = ssh2_pkt_getmp(ssh);
3993 s->g = ssh2_pkt_getmp(ssh);
3994 ssh->kex_ctx = dh_setup_group(s->p, s->g);
3995 s->kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
3996 s->kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
3997 } else {
3998 ssh->pkt_ctx |= SSH2_PKTCTX_DHGROUP1;
3999 ssh->kex_ctx = dh_setup_group1();
4000 s->kex_init_value = SSH2_MSG_KEXDH_INIT;
4001 s->kex_reply_value = SSH2_MSG_KEXDH_REPLY;
4002 }
4003
4004 logevent("Doing Diffie-Hellman key exchange");
4005 /*
4006 * Now generate and send e for Diffie-Hellman.
4007 */
4008 s->e = dh_create_e(ssh->kex_ctx, s->nbits * 2);
4009 ssh2_pkt_init(ssh, s->kex_init_value);
4010 ssh2_pkt_addmp(ssh, s->e);
4011 ssh2_pkt_send(ssh);
4012
4013 crWaitUntil(ispkt);
4014 if (ssh->pktin.type != s->kex_reply_value) {
4015 bombout((ssh,"expected key exchange reply packet from server"));
4016 crReturn(0);
4017 }
4018 ssh2_pkt_getstring(ssh, &s->hostkeydata, &s->hostkeylen);
4019 s->f = ssh2_pkt_getmp(ssh);
4020 ssh2_pkt_getstring(ssh, &s->sigdata, &s->siglen);
4021
4022 s->K = dh_find_K(ssh->kex_ctx, s->f);
4023
4024 sha_string(&ssh->exhash, s->hostkeydata, s->hostkeylen);
4025 if (ssh->kex == &ssh_diffiehellman_gex) {
4026 sha_uint32(&ssh->exhash, s->pbits);
4027 sha_mpint(&ssh->exhash, s->p);
4028 sha_mpint(&ssh->exhash, s->g);
4029 }
4030 sha_mpint(&ssh->exhash, s->e);
4031 sha_mpint(&ssh->exhash, s->f);
4032 sha_mpint(&ssh->exhash, s->K);
4033 SHA_Final(&ssh->exhash, s->exchange_hash);
4034
4035 dh_cleanup(ssh->kex_ctx);
4036
4037 #if 0
4038 debug(("Exchange hash is:\n"));
4039 dmemdump(s->exchange_hash, 20);
4040 #endif
4041
4042 s->hkey = ssh->hostkey->newkey(s->hostkeydata, s->hostkeylen);
4043 if (!s->hkey ||
4044 !ssh->hostkey->verifysig(s->hkey, s->sigdata, s->siglen,
4045 s->exchange_hash, 20)) {
4046 bombout((ssh,"Server's host key did not match the signature supplied"));
4047 crReturn(0);
4048 }
4049
4050 /*
4051 * Authenticate remote host: verify host key. (We've already
4052 * checked the signature of the exchange hash.)
4053 */
4054 s->keystr = ssh->hostkey->fmtkey(s->hkey);
4055 s->fingerprint = ssh->hostkey->fingerprint(s->hkey);
4056 verify_ssh_host_key(ssh->frontend,
4057 ssh->savedhost, ssh->savedport, ssh->hostkey->keytype,
4058 s->keystr, s->fingerprint);
4059 if (s->first_kex) { /* don't bother logging this in rekeys */
4060 logevent("Host key fingerprint is:");
4061 logevent(s->fingerprint);
4062 }
4063 sfree(s->fingerprint);
4064 sfree(s->keystr);
4065 ssh->hostkey->freekey(s->hkey);
4066
4067 /*
4068 * Send SSH2_MSG_NEWKEYS.
4069 */
4070 ssh2_pkt_init(ssh, SSH2_MSG_NEWKEYS);
4071 ssh2_pkt_send(ssh);
4072
4073 /*
4074 * Expect SSH2_MSG_NEWKEYS from server.
4075 */
4076 crWaitUntil(ispkt);
4077 if (ssh->pktin.type != SSH2_MSG_NEWKEYS) {
4078 bombout((ssh,"expected new-keys packet from server"));
4079 crReturn(0);
4080 }
4081
4082 /*
4083 * Create and initialise session keys.
4084 */
4085 if (ssh->cs_cipher_ctx)
4086 ssh->cscipher->free_context(ssh->cs_cipher_ctx);
4087 ssh->cscipher = s->cscipher_tobe;
4088 ssh->cs_cipher_ctx = ssh->cscipher->make_context();
4089
4090 if (ssh->sc_cipher_ctx)
4091 ssh->sccipher->free_context(ssh->sc_cipher_ctx);
4092 ssh->sccipher = s->sccipher_tobe;
4093 ssh->sc_cipher_ctx = ssh->sccipher->make_context();
4094
4095 if (ssh->cs_mac_ctx)
4096 ssh->csmac->free_context(ssh->cs_mac_ctx);
4097 ssh->csmac = s->csmac_tobe;
4098 ssh->cs_mac_ctx = ssh->csmac->make_context();
4099
4100 if (ssh->sc_mac_ctx)
4101 ssh->scmac->free_context(ssh->sc_mac_ctx);
4102 ssh->scmac = s->scmac_tobe;
4103 ssh->sc_mac_ctx = ssh->scmac->make_context();
4104
4105 if (ssh->cs_comp_ctx)
4106 ssh->cscomp->compress_cleanup(ssh->cs_comp_ctx);
4107 ssh->cscomp = s->cscomp_tobe;
4108 ssh->cs_comp_ctx = ssh->cscomp->compress_init();
4109
4110 if (ssh->sc_comp_ctx)
4111 ssh->sccomp->decompress_cleanup(ssh->sc_comp_ctx);
4112 ssh->sccomp = s->sccomp_tobe;
4113 ssh->sc_comp_ctx = ssh->sccomp->decompress_init();
4114
4115 /*
4116 * Set IVs after keys. Here we use the exchange hash from the
4117 * _first_ key exchange.
4118 */
4119 {
4120 unsigned char keyspace[40];
4121 if (s->first_kex)
4122 memcpy(ssh->v2_session_id, s->exchange_hash,
4123 sizeof(s->exchange_hash));
4124 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'C',keyspace);
4125 ssh->cscipher->setkey(ssh->cs_cipher_ctx, keyspace);
4126 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'D',keyspace);
4127 ssh->sccipher->setkey(ssh->sc_cipher_ctx, keyspace);
4128 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'A',keyspace);
4129 ssh->cscipher->setiv(ssh->cs_cipher_ctx, keyspace);
4130 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'B',keyspace);
4131 ssh->sccipher->setiv(ssh->sc_cipher_ctx, keyspace);
4132 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'E',keyspace);
4133 ssh->csmac->setkey(ssh->cs_mac_ctx, keyspace);
4134 ssh2_mkkey(ssh,s->K,s->exchange_hash,ssh->v2_session_id,'F',keyspace);
4135 ssh->scmac->setkey(ssh->sc_mac_ctx, keyspace);
4136 }
4137 logeventf(ssh, "Initialised %.200s client->server encryption",
4138 ssh->cscipher->text_name);
4139 logeventf(ssh, "Initialised %.200s server->client encryption",
4140 ssh->sccipher->text_name);
4141 if (ssh->cscomp->text_name)
4142 logeventf(ssh, "Initialised %s compression",
4143 ssh->cscomp->text_name);
4144 if (ssh->sccomp->text_name)
4145 logeventf(ssh, "Initialised %s decompression",
4146 ssh->sccomp->text_name);
4147
4148 /*
4149 * If this is the first key exchange phase, we must pass the
4150 * SSH2_MSG_NEWKEYS packet to the next layer, not because it
4151 * wants to see it but because it will need time to initialise
4152 * itself before it sees an actual packet. In subsequent key
4153 * exchange phases, we don't pass SSH2_MSG_NEWKEYS on, because
4154 * it would only confuse the layer above.
4155 */
4156 if (!s->first_kex) {
4157 crReturn(0);
4158 }
4159 s->first_kex = 0;
4160
4161 /*
4162 * Now we're encrypting. Begin returning 1 to the protocol main
4163 * function so that other things can run on top of the
4164 * transport. If we ever see a KEXINIT, we must go back to the
4165 * start.
4166 */
4167 while (!(ispkt && ssh->pktin.type == SSH2_MSG_KEXINIT)) {
4168 crReturn(1);
4169 }
4170 logevent("Server initiated key re-exchange");
4171 goto begin_key_exchange;
4172
4173 crFinish(1);
4174 }
4175
4176 /*
4177 * Add data to an SSH2 channel output buffer.
4178 */
4179 static void ssh2_add_channel_data(struct ssh_channel *c, char *buf,
4180 int len)
4181 {
4182 bufchain_add(&c->v.v2.outbuffer, buf, len);
4183 }
4184
4185 /*
4186 * Attempt to send data on an SSH2 channel.
4187 */
4188 static int ssh2_try_send(struct ssh_channel *c)
4189 {
4190 Ssh ssh = c->ssh;
4191
4192 while (c->v.v2.remwindow > 0 && bufchain_size(&c->v.v2.outbuffer) > 0) {
4193 int len;
4194 void *data;
4195 bufchain_prefix(&c->v.v2.outbuffer, &data, &len);
4196 if ((unsigned)len > c->v.v2.remwindow)
4197 len = c->v.v2.remwindow;
4198 if ((unsigned)len > c->v.v2.remmaxpkt)
4199 len = c->v.v2.remmaxpkt;
4200 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_DATA);
4201 ssh2_pkt_adduint32(ssh, c->remoteid);
4202 ssh2_pkt_addstring_start(ssh);
4203 ssh2_pkt_addstring_data(ssh, data, len);
4204 ssh2_pkt_send(ssh);
4205 bufchain_consume(&c->v.v2.outbuffer, len);
4206 c->v.v2.remwindow -= len;
4207 }
4208
4209 /*
4210 * After having sent as much data as we can, return the amount
4211 * still buffered.
4212 */
4213 return bufchain_size(&c->v.v2.outbuffer);
4214 }
4215
4216 /*
4217 * Potentially enlarge the window on an SSH2 channel.
4218 */
4219 static void ssh2_set_window(struct ssh_channel *c, unsigned newwin)
4220 {
4221 Ssh ssh = c->ssh;
4222
4223 /*
4224 * Never send WINDOW_ADJUST for a channel that the remote side
4225 * already thinks it's closed; there's no point, since it won't
4226 * be sending any more data anyway.
4227 */
4228 if (c->closes != 0)
4229 return;
4230
4231 if (newwin > c->v.v2.locwindow) {
4232 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST);
4233 ssh2_pkt_adduint32(ssh, c->remoteid);
4234 ssh2_pkt_adduint32(ssh, newwin - c->v.v2.locwindow);
4235 ssh2_pkt_send(ssh);
4236 c->v.v2.locwindow = newwin;
4237 }
4238 }
4239
4240 /*
4241 * Handle the SSH2 userauth and connection layers.
4242 */
4243 static void do_ssh2_authconn(Ssh ssh, unsigned char *in, int inlen, int ispkt)
4244 {
4245 struct do_ssh2_authconn_state {
4246 enum {
4247 AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE,
4248 AUTH_PASSWORD,
4249 AUTH_KEYBOARD_INTERACTIVE
4250 } method;
4251 enum {
4252 AUTH_TYPE_NONE,
4253 AUTH_TYPE_PUBLICKEY,
4254 AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
4255 AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
4256 AUTH_TYPE_PASSWORD,
4257 AUTH_TYPE_KEYBOARD_INTERACTIVE,
4258 AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET
4259 } type;
4260 int gotit, need_pw, can_pubkey, can_passwd, can_keyb_inter;
4261 int tried_pubkey_config, tried_agent, tried_keyb_inter;
4262 int kbd_inter_running;
4263 int we_are_in;
4264 int num_prompts, curr_prompt, echo;
4265 char username[100];
4266 int got_username;
4267 char pwprompt[200];
4268 char password[100];
4269 void *publickey_blob;
4270 int publickey_bloblen;
4271 unsigned char request[5], *response, *p;
4272 int responselen;
4273 int keyi, nkeys;
4274 int authed;
4275 char *pkblob, *alg, *commentp;
4276 int pklen, alglen, commentlen;
4277 int siglen, retlen, len;
4278 char *q, *agentreq, *ret;
4279 int try_send;
4280 };
4281 crState(do_ssh2_authconn_state);
4282
4283 crBegin(ssh->do_ssh2_authconn_crstate);
4284
4285 /*
4286 * Request userauth protocol, and await a response to it.
4287 */
4288 ssh2_pkt_init(ssh, SSH2_MSG_SERVICE_REQUEST);
4289 ssh2_pkt_addstring(ssh, "ssh-userauth");
4290 ssh2_pkt_send(ssh);
4291 crWaitUntilV(ispkt);
4292 if (ssh->pktin.type != SSH2_MSG_SERVICE_ACCEPT) {
4293 bombout((ssh,"Server refused user authentication protocol"));
4294 crReturnV;
4295 }
4296
4297 /*
4298 * We repeat this whole loop, including the username prompt,
4299 * until we manage a successful authentication. If the user
4300 * types the wrong _password_, they can be sent back to the
4301 * beginning to try another username, if this is configured on.
4302 * (If they specify a username in the config, they are never
4303 * asked, even if they do give a wrong password.)
4304 *
4305 * I think this best serves the needs of
4306 *
4307 * - the people who have no configuration, no keys, and just
4308 * want to try repeated (username,password) pairs until they
4309 * type both correctly
4310 *
4311 * - people who have keys and configuration but occasionally
4312 * need to fall back to passwords
4313 *
4314 * - people with a key held in Pageant, who might not have
4315 * logged in to a particular machine before; so they want to
4316 * type a username, and then _either_ their key will be
4317 * accepted, _or_ they will type a password. If they mistype
4318 * the username they will want to be able to get back and
4319 * retype it!
4320 */
4321 s->username[0] = '\0';
4322 s->got_username = FALSE;
4323 do {
4324 /*
4325 * Get a username.
4326 */
4327 if (s->got_username && !cfg.change_username) {
4328 /*
4329 * We got a username last time round this loop, and
4330 * with change_username turned off we don't try to get
4331 * it again.
4332 */
4333 } else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
4334 if (ssh_get_line && !ssh_getline_pw_only) {
4335 if (!ssh_get_line("login as: ",
4336 s->username, sizeof(s->username), FALSE)) {
4337 /*
4338 * get_line failed to get a username.
4339 * Terminate.
4340 */
4341 logevent("No username provided. Abandoning session.");
4342 ssh->state = SSH_STATE_CLOSED;
4343 crReturnV;
4344 }
4345 } else {
4346 int ret; /* need not be saved across crReturn */
4347 c_write_str(ssh, "login as: ");
4348 ssh->send_ok = 1;
4349 setup_userpass_input(ssh, s->username, sizeof(s->username), 1);
4350 do {
4351 crWaitUntilV(!ispkt);
4352 ret = process_userpass_input(ssh, in, inlen);
4353 } while (ret == 0);
4354 if (ret < 0)
4355 cleanup_exit(0);
4356 c_write_str(ssh, "\r\n");
4357 }
4358 s->username[strcspn(s->username, "\n\r")] = '\0';
4359 } else {
4360 char *stuff;
4361 strncpy(s->username, cfg.username, sizeof(s->username));
4362 s->username[sizeof(s->username)-1] = '\0';
4363 if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
4364 stuff = dupprintf("Using username \"%s\".\r\n", s->username);
4365 c_write_str(ssh, stuff);
4366 sfree(stuff);
4367 }
4368 }
4369 s->got_username = TRUE;
4370
4371 /*
4372 * Send an authentication request using method "none": (a)
4373 * just in case it succeeds, and (b) so that we know what
4374 * authentication methods we can usefully try next.
4375 */
4376 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4377
4378 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4379 ssh2_pkt_addstring(ssh, s->username);
4380 ssh2_pkt_addstring(ssh, "ssh-connection");/* service requested */
4381 ssh2_pkt_addstring(ssh, "none"); /* method */
4382 ssh2_pkt_send(ssh);
4383 s->type = AUTH_TYPE_NONE;
4384 s->gotit = FALSE;
4385 s->we_are_in = FALSE;
4386
4387 s->tried_pubkey_config = FALSE;
4388 s->tried_agent = FALSE;
4389 s->tried_keyb_inter = FALSE;
4390 s->kbd_inter_running = FALSE;
4391 /* Load the pub half of cfg.keyfile so we notice if it's in Pageant */
4392 if (*cfg.keyfile) {
4393 int keytype;
4394 logeventf(ssh, "Reading private key file \"%.150s\"", cfg.keyfile);
4395 keytype = key_type(cfg.keyfile);
4396 if (keytype == SSH_KEYTYPE_SSH2) {
4397 s->publickey_blob =
4398 ssh2_userkey_loadpub(cfg.keyfile, NULL,
4399 &s->publickey_bloblen);
4400 } else {
4401 char *msgbuf;
4402 logeventf(ssh, "Unable to use this key file (%s)",
4403 key_type_to_str(keytype));
4404 msgbuf = dupprintf("Unable to use key file \"%.150s\""
4405 " (%s)\r\n", cfg.keyfile,
4406 key_type_to_str(keytype));
4407 c_write_str(ssh, msgbuf);
4408 sfree(msgbuf);
4409 s->publickey_blob = NULL;
4410 }
4411 } else
4412 s->publickey_blob = NULL;
4413
4414 while (1) {
4415 /*
4416 * Wait for the result of the last authentication request.
4417 */
4418 if (!s->gotit)
4419 crWaitUntilV(ispkt);
4420 while (ssh->pktin.type == SSH2_MSG_USERAUTH_BANNER) {
4421 char *banner;
4422 int size;
4423 /*
4424 * Don't show the banner if we're operating in
4425 * non-verbose non-interactive mode. (It's probably
4426 * a script, which means nobody will read the
4427 * banner _anyway_, and moreover the printing of
4428 * the banner will screw up processing on the
4429 * output of (say) plink.)
4430 */
4431 if (flags & (FLAG_VERBOSE | FLAG_INTERACTIVE)) {
4432 ssh2_pkt_getstring(ssh, &banner, &size);
4433 if (banner)
4434 c_write_untrusted(ssh, banner, size);
4435 }
4436 crWaitUntilV(ispkt);
4437 }
4438 if (ssh->pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
4439 logevent("Access granted");
4440 s->we_are_in = TRUE;
4441 break;
4442 }
4443
4444 if (s->kbd_inter_running &&
4445 ssh->pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
4446 /*
4447 * This is either a further set-of-prompts packet
4448 * in keyboard-interactive authentication, or it's
4449 * the same one and we came back here with `gotit'
4450 * set. In the former case, we must reset the
4451 * curr_prompt variable.
4452 */
4453 if (!s->gotit)
4454 s->curr_prompt = 0;
4455 } else if (ssh->pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
4456 bombout((ssh,"Strange packet received during authentication: type %d",
4457 ssh->pktin.type));
4458 crReturnV;
4459 }
4460
4461 s->gotit = FALSE;
4462
4463 /*
4464 * OK, we're now sitting on a USERAUTH_FAILURE message, so
4465 * we can look at the string in it and know what we can
4466 * helpfully try next.
4467 */
4468 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE) {
4469 char *methods;
4470 int methlen;
4471 ssh2_pkt_getstring(ssh, &methods, &methlen);
4472 s->kbd_inter_running = FALSE;
4473 if (!ssh2_pkt_getbool(ssh)) {
4474 /*
4475 * We have received an unequivocal Access
4476 * Denied. This can translate to a variety of
4477 * messages:
4478 *
4479 * - if we'd just tried "none" authentication,
4480 * it's not worth printing anything at all
4481 *
4482 * - if we'd just tried a public key _offer_,
4483 * the message should be "Server refused our
4484 * key" (or no message at all if the key
4485 * came from Pageant)
4486 *
4487 * - if we'd just tried anything else, the
4488 * message really should be "Access denied".
4489 *
4490 * Additionally, if we'd just tried password
4491 * authentication, we should break out of this
4492 * whole loop so as to go back to the username
4493 * prompt.
4494 */
4495 if (s->type == AUTH_TYPE_NONE) {
4496 /* do nothing */
4497 } else if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
4498 s->type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
4499 if (s->type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
4500 c_write_str(ssh, "Server refused our key\r\n");
4501 logevent("Server refused public key");
4502 } else if (s->type==AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET) {
4503 /* server declined keyboard-interactive; ignore */
4504 } else {
4505 c_write_str(ssh, "Access denied\r\n");
4506 logevent("Access denied");
4507 if (s->type == AUTH_TYPE_PASSWORD) {
4508 s->we_are_in = FALSE;
4509 break;
4510 }
4511 }
4512 } else {
4513 c_write_str(ssh, "Further authentication required\r\n");
4514 logevent("Further authentication required");
4515 }
4516
4517 s->can_pubkey =
4518 in_commasep_string("publickey", methods, methlen);
4519 s->can_passwd =
4520 in_commasep_string("password", methods, methlen);
4521 s->can_keyb_inter = cfg.try_ki_auth &&
4522 in_commasep_string("keyboard-interactive", methods, methlen);
4523 }
4524
4525 s->method = 0;
4526 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4527
4528 /*
4529 * Most password/passphrase prompts will be
4530 * non-echoing, so we set this to 0 by default.
4531 * Exception is that some keyboard-interactive prompts
4532 * can be echoing, in which case we'll set this to 1.
4533 */
4534 s->echo = 0;
4535
4536 if (!s->method && s->can_pubkey &&
4537 agent_exists() && !s->tried_agent) {
4538 /*
4539 * Attempt public-key authentication using Pageant.
4540 */
4541 void *r;
4542 s->authed = FALSE;
4543
4544 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4545 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4546
4547 s->tried_agent = TRUE;
4548
4549 logevent("Pageant is running. Requesting keys.");
4550
4551 /* Request the keys held by the agent. */
4552 PUT_32BIT(s->request, 1);
4553 s->request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
4554 agent_query(s->request, 5, &r, &s->responselen);
4555 s->response = (unsigned char *) r;
4556 if (s->response && s->responselen >= 5 &&
4557 s->response[4] == SSH2_AGENT_IDENTITIES_ANSWER) {
4558 s->p = s->response + 5;
4559 s->nkeys = GET_32BIT(s->p);
4560 s->p += 4;
4561 {
4562 char buf[64];
4563 sprintf(buf, "Pageant has %d SSH2 keys", s->nkeys);
4564 logevent(buf);
4565 }
4566 for (s->keyi = 0; s->keyi < s->nkeys; s->keyi++) {
4567 void *vret;
4568
4569 {
4570 char buf[64];
4571 sprintf(buf, "Trying Pageant key #%d", s->keyi);
4572 logevent(buf);
4573 }
4574 s->pklen = GET_32BIT(s->p);
4575 s->p += 4;
4576 if (s->publickey_blob &&
4577 s->pklen == s->publickey_bloblen &&
4578 !memcmp(s->p, s->publickey_blob,
4579 s->publickey_bloblen)) {
4580 logevent("This key matches configured key file");
4581 s->tried_pubkey_config = 1;
4582 }
4583 s->pkblob = s->p;
4584 s->p += s->pklen;
4585 s->alglen = GET_32BIT(s->pkblob);
4586 s->alg = s->pkblob + 4;
4587 s->commentlen = GET_32BIT(s->p);
4588 s->p += 4;
4589 s->commentp = s->p;
4590 s->p += s->commentlen;
4591 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4592 ssh2_pkt_addstring(ssh, s->username);
4593 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4594 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4595 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4596 ssh2_pkt_addstring_start(ssh);
4597 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4598 ssh2_pkt_addstring_start(ssh);
4599 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4600 ssh2_pkt_send(ssh);
4601
4602 crWaitUntilV(ispkt);
4603 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4604 logevent("Key refused");
4605 continue;
4606 }
4607
4608 if (flags & FLAG_VERBOSE) {
4609 c_write_str(ssh, "Authenticating with "
4610 "public key \"");
4611 c_write(ssh, s->commentp, s->commentlen);
4612 c_write_str(ssh, "\" from agent\r\n");
4613 }
4614
4615 /*
4616 * Server is willing to accept the key.
4617 * Construct a SIGN_REQUEST.
4618 */
4619 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4620 ssh2_pkt_addstring(ssh, s->username);
4621 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4622 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4623 ssh2_pkt_addbool(ssh, TRUE);
4624 ssh2_pkt_addstring_start(ssh);
4625 ssh2_pkt_addstring_data(ssh, s->alg, s->alglen);
4626 ssh2_pkt_addstring_start(ssh);
4627 ssh2_pkt_addstring_data(ssh, s->pkblob, s->pklen);
4628
4629 s->siglen = ssh->pktout.length - 5 + 4 + 20;
4630 s->len = 1; /* message type */
4631 s->len += 4 + s->pklen; /* key blob */
4632 s->len += 4 + s->siglen; /* data to sign */
4633 s->len += 4; /* flags */
4634 s->agentreq = smalloc(4 + s->len);
4635 PUT_32BIT(s->agentreq, s->len);
4636 s->q = s->agentreq + 4;
4637 *s->q++ = SSH2_AGENTC_SIGN_REQUEST;
4638 PUT_32BIT(s->q, s->pklen);
4639 s->q += 4;
4640 memcpy(s->q, s->pkblob, s->pklen);
4641 s->q += s->pklen;
4642 PUT_32BIT(s->q, s->siglen);
4643 s->q += 4;
4644 /* Now the data to be signed... */
4645 PUT_32BIT(s->q, 20);
4646 s->q += 4;
4647 memcpy(s->q, ssh->v2_session_id, 20);
4648 s->q += 20;
4649 memcpy(s->q, ssh->pktout.data + 5,
4650 ssh->pktout.length - 5);
4651 s->q += ssh->pktout.length - 5;
4652 /* And finally the (zero) flags word. */
4653 PUT_32BIT(s->q, 0);
4654 agent_query(s->agentreq, s->len + 4, &vret, &s->retlen);
4655 s->ret = vret;
4656 sfree(s->agentreq);
4657 if (s->ret) {
4658 if (s->ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
4659 logevent("Sending Pageant's response");
4660 ssh2_add_sigblob(ssh, s->pkblob, s->pklen,
4661 s->ret + 9,
4662 GET_32BIT(s->ret + 5));
4663 ssh2_pkt_send(ssh);
4664 s->authed = TRUE;
4665 break;
4666 } else {
4667 logevent
4668 ("Pageant failed to answer challenge");
4669 sfree(s->ret);
4670 }
4671 }
4672 }
4673 if (s->authed)
4674 continue;
4675 }
4676 }
4677
4678 if (!s->method && s->can_pubkey && s->publickey_blob
4679 && !s->tried_pubkey_config) {
4680 unsigned char *pub_blob;
4681 char *algorithm, *comment;
4682 int pub_blob_len;
4683
4684 s->tried_pubkey_config = TRUE;
4685
4686 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4687 ssh->pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
4688
4689 /*
4690 * Try the public key supplied in the configuration.
4691 *
4692 * First, offer the public blob to see if the server is
4693 * willing to accept it.
4694 */
4695 pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
4696 &pub_blob_len);
4697 if (pub_blob) {
4698 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4699 ssh2_pkt_addstring(ssh, s->username);
4700 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4701 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4702 ssh2_pkt_addbool(ssh, FALSE); /* no signature included */
4703 ssh2_pkt_addstring(ssh, algorithm);
4704 ssh2_pkt_addstring_start(ssh);
4705 ssh2_pkt_addstring_data(ssh, pub_blob, pub_blob_len);
4706 ssh2_pkt_send(ssh);
4707 logevent("Offered public key"); /* FIXME */
4708
4709 crWaitUntilV(ispkt);
4710 if (ssh->pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
4711 s->gotit = TRUE;
4712 s->type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
4713 continue; /* key refused; give up on it */
4714 }
4715
4716 logevent("Offer of public key accepted");
4717 /*
4718 * Actually attempt a serious authentication using
4719 * the key.
4720 */
4721 if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
4722 sprintf(s->pwprompt,
4723 "Passphrase for key \"%.100s\": ",
4724 comment);
4725 s->need_pw = TRUE;
4726 } else {
4727 s->need_pw = FALSE;
4728 }
4729 c_write_str(ssh, "Authenticating with public key \"");
4730 c_write_str(ssh, comment);
4731 c_write_str(ssh, "\"\r\n");
4732 s->method = AUTH_PUBLICKEY_FILE;
4733 }
4734 }
4735
4736 if (!s->method && s->can_keyb_inter && !s->tried_keyb_inter) {
4737 s->method = AUTH_KEYBOARD_INTERACTIVE;
4738 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4739 s->tried_keyb_inter = TRUE;
4740
4741 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4742 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4743
4744 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4745 ssh2_pkt_addstring(ssh, s->username);
4746 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4747 ssh2_pkt_addstring(ssh, "keyboard-interactive"); /* method */
4748 ssh2_pkt_addstring(ssh, ""); /* lang */
4749 ssh2_pkt_addstring(ssh, "");
4750 ssh2_pkt_send(ssh);
4751
4752 crWaitUntilV(ispkt);
4753 if (ssh->pktin.type != SSH2_MSG_USERAUTH_INFO_REQUEST) {
4754 if (ssh->pktin.type == SSH2_MSG_USERAUTH_FAILURE)
4755 s->gotit = TRUE;
4756 logevent("Keyboard-interactive authentication refused");
4757 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE_QUIET;
4758 continue;
4759 }
4760
4761 s->kbd_inter_running = TRUE;
4762 s->curr_prompt = 0;
4763 }
4764
4765 if (s->kbd_inter_running) {
4766 s->method = AUTH_KEYBOARD_INTERACTIVE;
4767 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
4768 s->tried_keyb_inter = TRUE;
4769
4770 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4771 ssh->pkt_ctx |= SSH2_PKTCTX_KBDINTER;
4772
4773 if (s->curr_prompt == 0) {
4774 /*
4775 * We've got a fresh USERAUTH_INFO_REQUEST.
4776 * Display header data, and start going through
4777 * the prompts.
4778 */
4779 char *name, *inst, *lang;
4780 int name_len, inst_len, lang_len;
4781
4782 ssh2_pkt_getstring(ssh, &name, &name_len);
4783 ssh2_pkt_getstring(ssh, &inst, &inst_len);
4784 ssh2_pkt_getstring(ssh, &lang, &lang_len);
4785 if (name_len > 0) {
4786 c_write_untrusted(ssh, name, name_len);
4787 c_write_str(ssh, "\r\n");
4788 }
4789 if (inst_len > 0) {
4790 c_write_untrusted(ssh, inst, inst_len);
4791 c_write_str(ssh, "\r\n");
4792 }
4793 s->num_prompts = ssh2_pkt_getuint32(ssh);
4794 }
4795
4796 /*
4797 * If there are prompts remaining in the packet,
4798 * display one and get a response.
4799 */
4800 if (s->curr_prompt < s->num_prompts) {
4801 char *prompt;
4802 int prompt_len;
4803
4804 ssh2_pkt_getstring(ssh, &prompt, &prompt_len);
4805 if (prompt_len > 0) {
4806 strncpy(s->pwprompt, prompt, sizeof(s->pwprompt));
4807 s->pwprompt[prompt_len < sizeof(s->pwprompt) ?
4808 prompt_len : sizeof(s->pwprompt)-1] = '\0';
4809 } else {
4810 strcpy(s->pwprompt,
4811 "<server failed to send prompt>: ");
4812 }
4813 s->echo = ssh2_pkt_getbool(ssh);
4814 s->need_pw = TRUE;
4815 } else
4816 s->need_pw = FALSE;
4817 }
4818
4819 if (!s->method && s->can_passwd) {
4820 s->method = AUTH_PASSWORD;
4821 ssh->pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
4822 ssh->pkt_ctx |= SSH2_PKTCTX_PASSWORD;
4823 sprintf(s->pwprompt, "%.90s@%.90s's password: ", s->username,
4824 ssh->savedhost);
4825 s->need_pw = TRUE;
4826 }
4827
4828 if (s->need_pw) {
4829 if (ssh_get_line) {
4830 if (!ssh_get_line(s->pwprompt, s->password,
4831 sizeof(s->password), TRUE)) {
4832 /*
4833 * get_line failed to get a password (for
4834 * example because one was supplied on the
4835 * command line which has already failed to
4836 * work). Terminate.
4837 */
4838 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
4839 ssh2_pkt_adduint32(ssh,SSH2_DISCONNECT_BY_APPLICATION);
4840 ssh2_pkt_addstring(ssh, "No more passwords available"
4841 " to try");
4842 ssh2_pkt_addstring(ssh, "en"); /* language tag */
4843 ssh2_pkt_send(ssh);
4844 logevent("Unable to authenticate");
4845 connection_fatal(ssh->frontend,
4846 "Unable to authenticate");
4847 ssh->state = SSH_STATE_CLOSED;
4848 crReturnV;
4849 }
4850 } else {
4851 int ret; /* need not be saved across crReturn */
4852 c_write_untrusted(ssh, s->pwprompt, strlen(s->pwprompt));
4853 ssh->send_ok = 1;
4854
4855 setup_userpass_input(ssh, s->password,
4856 sizeof(s->password), s->echo);
4857 do {
4858 crWaitUntilV(!ispkt);
4859 ret = process_userpass_input(ssh, in, inlen);
4860 } while (ret == 0);
4861 if (ret < 0)
4862 cleanup_exit(0);
4863 c_write_str(ssh, "\r\n");
4864 }
4865 }
4866
4867 if (s->method == AUTH_PUBLICKEY_FILE) {
4868 /*
4869 * We have our passphrase. Now try the actual authentication.
4870 */
4871 struct ssh2_userkey *key;
4872
4873 key = ssh2_load_userkey(cfg.keyfile, s->password);
4874 if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
4875 if (key == SSH2_WRONG_PASSPHRASE) {
4876 c_write_str(ssh, "Wrong passphrase\r\n");
4877 s->tried_pubkey_config = FALSE;
4878 } else {
4879 c_write_str(ssh, "Unable to load private key\r\n");
4880 s->tried_pubkey_config = TRUE;
4881 }
4882 /* Send a spurious AUTH_NONE to return to the top. */
4883 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4884 ssh2_pkt_addstring(ssh, s->username);
4885 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4886 ssh2_pkt_addstring(ssh, "none"); /* method */
4887 ssh2_pkt_send(ssh);
4888 s->type = AUTH_TYPE_NONE;
4889 } else {
4890 unsigned char *pkblob, *sigblob, *sigdata;
4891 int pkblob_len, sigblob_len, sigdata_len;
4892
4893 /*
4894 * We have loaded the private key and the server
4895 * has announced that it's willing to accept it.
4896 * Hallelujah. Generate a signature and send it.
4897 */
4898 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4899 ssh2_pkt_addstring(ssh, s->username);
4900 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4901 ssh2_pkt_addstring(ssh, "publickey"); /* method */
4902 ssh2_pkt_addbool(ssh, TRUE);
4903 ssh2_pkt_addstring(ssh, key->alg->name);
4904 pkblob = key->alg->public_blob(key->data, &pkblob_len);
4905 ssh2_pkt_addstring_start(ssh);
4906 ssh2_pkt_addstring_data(ssh, pkblob, pkblob_len);
4907
4908 /*
4909 * The data to be signed is:
4910 *
4911 * string session-id
4912 *
4913 * followed by everything so far placed in the
4914 * outgoing packet.
4915 */
4916 sigdata_len = ssh->pktout.length - 5 + 4 + 20;
4917 sigdata = smalloc(sigdata_len);
4918 PUT_32BIT(sigdata, 20);
4919 memcpy(sigdata + 4, ssh->v2_session_id, 20);
4920 memcpy(sigdata + 24, ssh->pktout.data + 5,
4921 ssh->pktout.length - 5);
4922 sigblob = key->alg->sign(key->data, sigdata,
4923 sigdata_len, &sigblob_len);
4924 ssh2_add_sigblob(ssh, pkblob, pkblob_len,
4925 sigblob, sigblob_len);
4926 sfree(pkblob);
4927 sfree(sigblob);
4928 sfree(sigdata);
4929
4930 ssh2_pkt_send(ssh);
4931 s->type = AUTH_TYPE_PUBLICKEY;
4932 }
4933 } else if (s->method == AUTH_PASSWORD) {
4934 /*
4935 * We send the password packet lumped tightly together with
4936 * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
4937 * string long enough to make the total length of the two
4938 * packets constant. This should ensure that a passive
4939 * listener doing traffic analyis can't work out the length
4940 * of the password.
4941 *
4942 * For this to work, we need an assumption about the
4943 * maximum length of the password packet. I think 256 is
4944 * pretty conservative. Anyone using a password longer than
4945 * that probably doesn't have much to worry about from
4946 * people who find out how long their password is!
4947 */
4948 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_REQUEST);
4949 ssh2_pkt_addstring(ssh, s->username);
4950 ssh2_pkt_addstring(ssh, "ssh-connection"); /* service requested */
4951 ssh2_pkt_addstring(ssh, "password");
4952 ssh2_pkt_addbool(ssh, FALSE);
4953 ssh2_pkt_addstring(ssh, s->password);
4954 ssh2_pkt_defer(ssh);
4955 /*
4956 * We'll include a string that's an exact multiple of the
4957 * cipher block size. If the cipher is NULL for some
4958 * reason, we don't do this trick at all because we gain
4959 * nothing by it.
4960 */
4961 if (ssh->cscipher) {
4962 int stringlen, i;
4963
4964 stringlen = (256 - ssh->deferred_len);
4965 stringlen += ssh->cscipher->blksize - 1;
4966 stringlen -= (stringlen % ssh->cscipher->blksize);
4967 if (ssh->cscomp) {
4968 /*
4969 * Temporarily disable actual compression,
4970 * so we can guarantee to get this string
4971 * exactly the length we want it. The
4972 * compression-disabling routine should
4973 * return an integer indicating how many
4974 * bytes we should adjust our string length
4975 * by.
4976 */
4977 stringlen -=
4978 ssh->cscomp->disable_compression(ssh->cs_comp_ctx);
4979 }
4980 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
4981 ssh2_pkt_addstring_start(ssh);
4982 for (i = 0; i < stringlen; i++) {
4983 char c = (char) random_byte();
4984 ssh2_pkt_addstring_data(ssh, &c, 1);
4985 }
4986 ssh2_pkt_defer(ssh);
4987 }
4988 ssh_pkt_defersend(ssh);
4989 logevent("Sent password");
4990 s->type = AUTH_TYPE_PASSWORD;
4991 } else if (s->method == AUTH_KEYBOARD_INTERACTIVE) {
4992 if (s->curr_prompt == 0) {
4993 ssh2_pkt_init(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE);
4994 ssh2_pkt_adduint32(ssh, s->num_prompts);
4995 }
4996 if (s->need_pw) { /* only add pw if we just got one! */
4997 ssh2_pkt_addstring(ssh, s->password);
4998 memset(s->password, 0, sizeof(s->password));
4999 s->curr_prompt++;
5000 }
5001 if (s->curr_prompt >= s->num_prompts) {
5002 ssh2_pkt_send(ssh);
5003 } else {
5004 /*
5005 * If there are prompts remaining, we set
5006 * `gotit' so that we won't attempt to get
5007 * another packet. Then we go back round the
5008 * loop and will end up retrieving another
5009 * prompt out of the existing packet. Funky or
5010 * what?
5011 */
5012 s->gotit = TRUE;
5013 }
5014 s->type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
5015 } else {
5016 c_write_str(ssh, "No supported authentication methods"
5017 " left to try!\r\n");
5018 logevent("No supported authentications offered."
5019 " Disconnecting");
5020 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5021 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5022 ssh2_pkt_addstring(ssh, "No supported authentication"
5023 " methods available");
5024 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5025 ssh2_pkt_send(ssh);
5026 ssh->state = SSH_STATE_CLOSED;
5027 crReturnV;
5028 }
5029 }
5030 } while (!s->we_are_in);
5031
5032 /*
5033 * Now we're authenticated for the connection protocol. The
5034 * connection protocol will automatically have started at this
5035 * point; there's no need to send SERVICE_REQUEST.
5036 */
5037
5038 /*
5039 * So now create a channel with a session in it.
5040 */
5041 ssh->channels = newtree234(ssh_channelcmp);
5042 ssh->mainchan = smalloc(sizeof(struct ssh_channel));
5043 ssh->mainchan->ssh = ssh;
5044 ssh->mainchan->localid = alloc_channel_id(ssh);
5045 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
5046 ssh2_pkt_addstring(ssh, "session");
5047 ssh2_pkt_adduint32(ssh, ssh->mainchan->localid);
5048 ssh->mainchan->v.v2.locwindow = OUR_V2_WINSIZE;
5049 ssh2_pkt_adduint32(ssh, ssh->mainchan->v.v2.locwindow);/* our window size */
5050 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5051 ssh2_pkt_send(ssh);
5052 crWaitUntilV(ispkt);
5053 if (ssh->pktin.type != SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5054 bombout((ssh,"Server refused to open a session"));
5055 crReturnV;
5056 /* FIXME: error data comes back in FAILURE packet */
5057 }
5058 if (ssh2_pkt_getuint32(ssh) != ssh->mainchan->localid) {
5059 bombout((ssh,"Server's channel confirmation cited wrong channel"));
5060 crReturnV;
5061 }
5062 ssh->mainchan->remoteid = ssh2_pkt_getuint32(ssh);
5063 ssh->mainchan->type = CHAN_MAINSESSION;
5064 ssh->mainchan->closes = 0;
5065 ssh->mainchan->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5066 ssh->mainchan->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5067 bufchain_init(&ssh->mainchan->v.v2.outbuffer);
5068 add234(ssh->channels, ssh->mainchan);
5069 logevent("Opened channel for session");
5070
5071 /*
5072 * Potentially enable X11 forwarding.
5073 */
5074 if (cfg.x11_forward) {
5075 char proto[20], data[64];
5076 logevent("Requesting X11 forwarding");
5077 ssh->x11auth = x11_invent_auth(proto, sizeof(proto),
5078 data, sizeof(data));
5079 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5080 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5081 ssh2_pkt_addstring(ssh, "x11-req");
5082 ssh2_pkt_addbool(ssh, 1); /* want reply */
5083 ssh2_pkt_addbool(ssh, 0); /* many connections */
5084 ssh2_pkt_addstring(ssh, proto);
5085 ssh2_pkt_addstring(ssh, data);
5086 ssh2_pkt_adduint32(ssh, 0); /* screen number */
5087 ssh2_pkt_send(ssh);
5088
5089 do {
5090 crWaitUntilV(ispkt);
5091 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5092 unsigned i = ssh2_pkt_getuint32(ssh);
5093 struct ssh_channel *c;
5094 c = find234(ssh->channels, &i, ssh_channelfind);
5095 if (!c)
5096 continue; /* nonexistent channel */
5097 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5098 }
5099 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5100
5101 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5102 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5103 bombout((ssh,"Unexpected response to X11 forwarding request:"
5104 " packet type %d", ssh->pktin.type));
5105 crReturnV;
5106 }
5107 logevent("X11 forwarding refused");
5108 } else {
5109 logevent("X11 forwarding enabled");
5110 ssh->X11_fwd_enabled = TRUE;
5111 }
5112 }
5113
5114 /*
5115 * Enable port forwardings.
5116 */
5117 {
5118 char type;
5119 int n;
5120 int sport,dport,sserv,dserv;
5121 char sports[256], dports[256], saddr[256], host[256];
5122
5123 ssh->rportfwds = newtree234(ssh_rportcmp_ssh2);
5124 /* Add port forwardings. */
5125 ssh->portfwd_strptr = cfg.portfwd;
5126 while (*ssh->portfwd_strptr) {
5127 type = *ssh->portfwd_strptr++;
5128 saddr[0] = '\0';
5129 n = 0;
5130 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != '\t') {
5131 if (*ssh->portfwd_strptr == ':') {
5132 /*
5133 * We've seen a colon in the middle of the
5134 * source port number. This means that
5135 * everything we've seen until now is the
5136 * source _address_, so we'll move it into
5137 * saddr and start sports from the beginning
5138 * again.
5139 */
5140 ssh->portfwd_strptr++;
5141 sports[n] = '\0';
5142 strcpy(saddr, sports);
5143 n = 0;
5144 }
5145 if (n < 255) sports[n++] = *ssh->portfwd_strptr++;
5146 }
5147 sports[n] = 0;
5148 if (*ssh->portfwd_strptr == '\t')
5149 ssh->portfwd_strptr++;
5150 n = 0;
5151 while (*ssh->portfwd_strptr && *ssh->portfwd_strptr != ':') {
5152 if (n < 255) host[n++] = *ssh->portfwd_strptr++;
5153 }
5154 host[n] = 0;
5155 if (*ssh->portfwd_strptr == ':')
5156 ssh->portfwd_strptr++;
5157 n = 0;
5158 while (*ssh->portfwd_strptr) {
5159 if (n < 255) dports[n++] = *ssh->portfwd_strptr++;
5160 }
5161 dports[n] = 0;
5162 ssh->portfwd_strptr++;
5163 dport = atoi(dports);
5164 dserv = 0;
5165 if (dport == 0) {
5166 dserv = 1;
5167 dport = net_service_lookup(dports);
5168 if (!dport) {
5169 logeventf(ssh, "Service lookup failed for destination"
5170 " port \"%s\"", dports);
5171 }
5172 }
5173 sport = atoi(sports);
5174 sserv = 0;
5175 if (sport == 0) {
5176 sserv = 1;
5177 sport = net_service_lookup(sports);
5178 if (!sport) {
5179 logeventf(ssh, "Service lookup failed for source"
5180 " port \"%s\"", sports);
5181 }
5182 }
5183 if (sport && dport) {
5184 if (type == 'L') {
5185 pfd_addforward(host, dport, *saddr ? saddr : NULL,
5186 sport, ssh);
5187 logeventf(ssh, "Local port %.*s%.*s%.*s%.*s%d%.*s"
5188 " forwarding to %s:%.*s%.*s%d%.*s",
5189 (int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
5190 (int)(*saddr?1:0), ":",
5191 (int)(sserv ? strlen(sports) : 0), sports,
5192 sserv, "(", sport, sserv, ")",
5193 host,
5194 (int)(dserv ? strlen(dports) : 0), dports,
5195 dserv, "(", dport, dserv, ")");
5196 } else {
5197 struct ssh_rportfwd *pf;
5198 pf = smalloc(sizeof(*pf));
5199 strcpy(pf->dhost, host);
5200 pf->dport = dport;
5201 pf->sport = sport;
5202 if (add234(ssh->rportfwds, pf) != pf) {
5203 logeventf(ssh, "Duplicate remote port forwarding"
5204 " to %s:%d", host, dport);
5205 sfree(pf);
5206 } else {
5207 logeventf(ssh, "Requesting remote port "
5208 "%.*s%.*s%.*s%.*s%d%.*s"
5209 " forward to %s:%.*s%.*s%d%.*s",
5210 (int)(*saddr?strlen(saddr):0),
5211 *saddr?saddr:NULL,
5212 (int)(*saddr?1:0), ":",
5213 (int)(sserv ? strlen(sports) : 0), sports,
5214 sserv, "(", sport, sserv, ")",
5215 host,
5216 (int)(dserv ? strlen(dports) : 0), dports,
5217 dserv, "(", dport, dserv, ")");
5218 ssh2_pkt_init(ssh, SSH2_MSG_GLOBAL_REQUEST);
5219 ssh2_pkt_addstring(ssh, "tcpip-forward");
5220 ssh2_pkt_addbool(ssh, 1);/* want reply */
5221 if (*saddr)
5222 ssh2_pkt_addstring(ssh, saddr);
5223 if (cfg.rport_acceptall)
5224 ssh2_pkt_addstring(ssh, "0.0.0.0");
5225 else
5226 ssh2_pkt_addstring(ssh, "127.0.0.1");
5227 ssh2_pkt_adduint32(ssh, sport);
5228 ssh2_pkt_send(ssh);
5229
5230 do {
5231 crWaitUntilV(ispkt);
5232 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5233 unsigned i = ssh2_pkt_getuint32(ssh);
5234 struct ssh_channel *c;
5235 c = find234(ssh->channels, &i, ssh_channelfind);
5236 if (!c)
5237 continue;/* nonexistent channel */
5238 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5239 }
5240 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5241
5242 if (ssh->pktin.type != SSH2_MSG_REQUEST_SUCCESS) {
5243 if (ssh->pktin.type != SSH2_MSG_REQUEST_FAILURE) {
5244 bombout((ssh,"Unexpected response to port "
5245 "forwarding request: packet type %d",
5246 ssh->pktin.type));
5247 crReturnV;
5248 }
5249 logevent("Server refused this port forwarding");
5250 } else {
5251 logevent("Remote port forwarding enabled");
5252 }
5253 }
5254 }
5255 }
5256 }
5257 }
5258
5259 /*
5260 * Potentially enable agent forwarding.
5261 */
5262 if (cfg.agentfwd && agent_exists()) {
5263 logevent("Requesting OpenSSH-style agent forwarding");
5264 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5265 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
5266 ssh2_pkt_addstring(ssh, "auth-agent-req@openssh.com");
5267 ssh2_pkt_addbool(ssh, 1); /* want reply */
5268 ssh2_pkt_send(ssh);
5269
5270 do {
5271 crWaitUntilV(ispkt);
5272 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5273 unsigned i = ssh2_pkt_getuint32(ssh);
5274 struct ssh_channel *c;
5275 c = find234(ssh->channels, &i, ssh_channelfind);
5276 if (!c)
5277 continue; /* nonexistent channel */
5278 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5279 }
5280 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5281
5282 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5283 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5284 bombout((ssh,"Unexpected response to agent forwarding request:"
5285 " packet type %d", ssh->pktin.type));
5286 crReturnV;
5287 }
5288 logevent("Agent forwarding refused");
5289 } else {
5290 logevent("Agent forwarding enabled");
5291 ssh->agentfwd_enabled = TRUE;
5292 }
5293 }
5294
5295 /*
5296 * Now allocate a pty for the session.
5297 */
5298 if (!cfg.nopty) {
5299 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5300 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5301 ssh2_pkt_addstring(ssh, "pty-req");
5302 ssh2_pkt_addbool(ssh, 1); /* want reply */
5303 ssh2_pkt_addstring(ssh, cfg.termtype);
5304 ssh2_pkt_adduint32(ssh, ssh->term_width);
5305 ssh2_pkt_adduint32(ssh, ssh->term_height);
5306 ssh2_pkt_adduint32(ssh, 0); /* pixel width */
5307 ssh2_pkt_adduint32(ssh, 0); /* pixel height */
5308 ssh2_pkt_addstring_start(ssh);
5309 ssh2_pkt_addstring_data(ssh, "\0", 1); /* TTY_OP_END, no special options */
5310 ssh2_pkt_send(ssh);
5311 ssh->state = SSH_STATE_INTERMED;
5312
5313 do {
5314 crWaitUntilV(ispkt);
5315 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5316 unsigned i = ssh2_pkt_getuint32(ssh);
5317 struct ssh_channel *c;
5318 c = find234(ssh->channels, &i, ssh_channelfind);
5319 if (!c)
5320 continue; /* nonexistent channel */
5321 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5322 }
5323 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5324
5325 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5326 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5327 bombout((ssh,"Unexpected response to pty request:"
5328 " packet type %d", ssh->pktin.type));
5329 crReturnV;
5330 }
5331 c_write_str(ssh, "Server refused to allocate pty\r\n");
5332 ssh->editing = ssh->echoing = 1;
5333 } else {
5334 logevent("Allocated pty");
5335 }
5336 } else {
5337 ssh->editing = ssh->echoing = 1;
5338 }
5339
5340 /*
5341 * Start a shell or a remote command. We may have to attempt
5342 * this twice if the config data has provided a second choice
5343 * of command.
5344 */
5345 while (1) {
5346 int subsys;
5347 char *cmd;
5348
5349 if (ssh->fallback_cmd) {
5350 subsys = cfg.ssh_subsys2;
5351 cmd = cfg.remote_cmd_ptr2;
5352 } else {
5353 subsys = cfg.ssh_subsys;
5354 cmd = cfg.remote_cmd_ptr;
5355 }
5356
5357 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
5358 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid); /* recipient channel */
5359 if (subsys) {
5360 ssh2_pkt_addstring(ssh, "subsystem");
5361 ssh2_pkt_addbool(ssh, 1); /* want reply */
5362 ssh2_pkt_addstring(ssh, cmd);
5363 } else if (*cmd) {
5364 ssh2_pkt_addstring(ssh, "exec");
5365 ssh2_pkt_addbool(ssh, 1); /* want reply */
5366 ssh2_pkt_addstring(ssh, cmd);
5367 } else {
5368 ssh2_pkt_addstring(ssh, "shell");
5369 ssh2_pkt_addbool(ssh, 1); /* want reply */
5370 }
5371 ssh2_pkt_send(ssh);
5372 do {
5373 crWaitUntilV(ispkt);
5374 if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5375 unsigned i = ssh2_pkt_getuint32(ssh);
5376 struct ssh_channel *c;
5377 c = find234(ssh->channels, &i, ssh_channelfind);
5378 if (!c)
5379 continue; /* nonexistent channel */
5380 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5381 }
5382 } while (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
5383 if (ssh->pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
5384 if (ssh->pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
5385 bombout((ssh,"Unexpected response to shell/command request:"
5386 " packet type %d", ssh->pktin.type));
5387 crReturnV;
5388 }
5389 /*
5390 * We failed to start the command. If this is the
5391 * fallback command, we really are finished; if it's
5392 * not, and if the fallback command exists, try falling
5393 * back to it before complaining.
5394 */
5395 if (!ssh->fallback_cmd && cfg.remote_cmd_ptr2 != NULL) {
5396 logevent("Primary command failed; attempting fallback");
5397 ssh->fallback_cmd = TRUE;
5398 continue;
5399 }
5400 bombout((ssh,"Server refused to start a shell/command"));
5401 crReturnV;
5402 } else {
5403 logevent("Started a shell/command");
5404 }
5405 break;
5406 }
5407
5408 ssh->state = SSH_STATE_SESSION;
5409 if (ssh->size_needed)
5410 ssh_size(ssh, ssh->term_width, ssh->term_height);
5411 if (ssh->eof_needed)
5412 ssh_special(ssh, TS_EOF);
5413
5414 /*
5415 * Transfer data!
5416 */
5417 if (ssh->ldisc)
5418 ldisc_send(ssh->ldisc, NULL, 0, 0);/* cause ldisc to notice changes */
5419 ssh->send_ok = 1;
5420 while (1) {
5421 crReturnV;
5422 s->try_send = FALSE;
5423 if (ispkt) {
5424 if (ssh->pktin.type == SSH2_MSG_CHANNEL_DATA ||
5425 ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA) {
5426 char *data;
5427 int length;
5428 unsigned i = ssh2_pkt_getuint32(ssh);
5429 struct ssh_channel *c;
5430 c = find234(ssh->channels, &i, ssh_channelfind);
5431 if (!c)
5432 continue; /* nonexistent channel */
5433 if (ssh->pktin.type == SSH2_MSG_CHANNEL_EXTENDED_DATA &&
5434 ssh2_pkt_getuint32(ssh) != SSH2_EXTENDED_DATA_STDERR)
5435 continue; /* extended but not stderr */
5436 ssh2_pkt_getstring(ssh, &data, &length);
5437 if (data) {
5438 int bufsize;
5439 c->v.v2.locwindow -= length;
5440 switch (c->type) {
5441 case CHAN_MAINSESSION:
5442 bufsize =
5443 from_backend(ssh->frontend, ssh->pktin.type ==
5444 SSH2_MSG_CHANNEL_EXTENDED_DATA,
5445 data, length);
5446 break;
5447 case CHAN_X11:
5448 bufsize = x11_send(c->u.x11.s, data, length);
5449 break;
5450 case CHAN_SOCKDATA:
5451 bufsize = pfd_send(c->u.pfd.s, data, length);
5452 break;
5453 case CHAN_AGENT:
5454 while (length > 0) {
5455 if (c->u.a.lensofar < 4) {
5456 int l = min(4 - c->u.a.lensofar, length);
5457 memcpy(c->u.a.msglen + c->u.a.lensofar,
5458 data, l);
5459 data += l;
5460 length -= l;
5461 c->u.a.lensofar += l;
5462 }
5463 if (c->u.a.lensofar == 4) {
5464 c->u.a.totallen =
5465 4 + GET_32BIT(c->u.a.msglen);
5466 c->u.a.message = smalloc(c->u.a.totallen);
5467 memcpy(c->u.a.message, c->u.a.msglen, 4);
5468 }
5469 if (c->u.a.lensofar >= 4 && length > 0) {
5470 int l =
5471 min(c->u.a.totallen - c->u.a.lensofar,
5472 length);
5473 memcpy(c->u.a.message + c->u.a.lensofar,
5474 data, l);
5475 data += l;
5476 length -= l;
5477 c->u.a.lensofar += l;
5478 }
5479 if (c->u.a.lensofar == c->u.a.totallen) {
5480 void *reply, *sentreply;
5481 int replylen;
5482 agent_query(c->u.a.message,
5483 c->u.a.totallen, &reply,
5484 &replylen);
5485 if (reply)
5486 sentreply = reply;
5487 else {
5488 /* Fake SSH_AGENT_FAILURE. */
5489 sentreply = "\0\0\0\1\5";
5490 replylen = 5;
5491 }
5492 ssh2_add_channel_data(c, sentreply, replylen);
5493 s->try_send = TRUE;
5494 if (reply)
5495 sfree(reply);
5496 sfree(c->u.a.message);
5497 c->u.a.lensofar = 0;
5498 }
5499 }
5500 bufsize = 0;
5501 break;
5502 }
5503 /*
5504 * If we are not buffering too much data,
5505 * enlarge the window again at the remote side.
5506 */
5507 if (bufsize < OUR_V2_WINSIZE)
5508 ssh2_set_window(c, OUR_V2_WINSIZE - bufsize);
5509 }
5510 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_EOF) {
5511 unsigned i = ssh2_pkt_getuint32(ssh);
5512 struct ssh_channel *c;
5513
5514 c = find234(ssh->channels, &i, ssh_channelfind);
5515 if (!c)
5516 continue; /* nonexistent channel */
5517
5518 if (c->type == CHAN_X11) {
5519 /*
5520 * Remote EOF on an X11 channel means we should
5521 * wrap up and close the channel ourselves.
5522 */
5523 x11_close(c->u.x11.s);
5524 sshfwd_close(c);
5525 } else if (c->type == CHAN_AGENT) {
5526 sshfwd_close(c);
5527 } else if (c->type == CHAN_SOCKDATA) {
5528 pfd_close(c->u.pfd.s);
5529 sshfwd_close(c);
5530 }
5531 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
5532 unsigned i = ssh2_pkt_getuint32(ssh);
5533 struct ssh_channel *c;
5534
5535 c = find234(ssh->channels, &i, ssh_channelfind);
5536 if (!c || ((int)c->remoteid) == -1) {
5537 bombout((ssh,"Received CHANNEL_CLOSE for %s channel %d\n",
5538 c ? "half-open" : "nonexistent", i));
5539 }
5540 /* Do pre-close processing on the channel. */
5541 switch (c->type) {
5542 case CHAN_MAINSESSION:
5543 break; /* nothing to see here, move along */
5544 case CHAN_X11:
5545 if (c->u.x11.s != NULL)
5546 x11_close(c->u.x11.s);
5547 sshfwd_close(c);
5548 break;
5549 case CHAN_AGENT:
5550 sshfwd_close(c);
5551 break;
5552 case CHAN_SOCKDATA:
5553 if (c->u.pfd.s != NULL)
5554 pfd_close(c->u.pfd.s);
5555 sshfwd_close(c);
5556 break;
5557 }
5558 if (c->closes == 0) {
5559 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5560 ssh2_pkt_adduint32(ssh, c->remoteid);
5561 ssh2_pkt_send(ssh);
5562 }
5563 del234(ssh->channels, c);
5564 bufchain_clear(&c->v.v2.outbuffer);
5565 sfree(c);
5566
5567 /*
5568 * See if that was the last channel left open.
5569 */
5570 if (count234(ssh->channels) == 0) {
5571 #if 0
5572 /*
5573 * We used to send SSH_MSG_DISCONNECT here,
5574 * because I'd believed that _every_ conforming
5575 * SSH2 connection had to end with a disconnect
5576 * being sent by at least one side; apparently
5577 * I was wrong and it's perfectly OK to
5578 * unceremoniously slam the connection shut
5579 * when you're done, and indeed OpenSSH feels
5580 * this is more polite than sending a
5581 * DISCONNECT. So now we don't.
5582 */
5583 logevent("All channels closed. Disconnecting");
5584 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5585 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5586 ssh2_pkt_addstring(ssh, "All open channels closed");
5587 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5588 ssh2_pkt_send(ssh);
5589 #endif
5590 ssh->state = SSH_STATE_CLOSED;
5591 crReturnV;
5592 }
5593 continue; /* remote sends close; ignore (FIXME) */
5594 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
5595 unsigned i = ssh2_pkt_getuint32(ssh);
5596 struct ssh_channel *c;
5597 c = find234(ssh->channels, &i, ssh_channelfind);
5598 if (!c)
5599 continue; /* nonexistent channel */
5600 c->v.v2.remwindow += ssh2_pkt_getuint32(ssh);
5601 s->try_send = TRUE;
5602 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_CONFIRMATION) {
5603 unsigned i = ssh2_pkt_getuint32(ssh);
5604 struct ssh_channel *c;
5605 c = find234(ssh->channels, &i, ssh_channelfind);
5606 if (!c)
5607 continue; /* nonexistent channel */
5608 if (c->type != CHAN_SOCKDATA_DORMANT)
5609 continue; /* dunno why they're confirming this */
5610 c->remoteid = ssh2_pkt_getuint32(ssh);
5611 c->type = CHAN_SOCKDATA;
5612 c->v.v2.remwindow = ssh2_pkt_getuint32(ssh);
5613 c->v.v2.remmaxpkt = ssh2_pkt_getuint32(ssh);
5614 if (c->u.pfd.s)
5615 pfd_confirm(c->u.pfd.s);
5616 if (c->closes) {
5617 /*
5618 * We have a pending close on this channel,
5619 * which we decided on before the server acked
5620 * the channel open. So now we know the
5621 * remoteid, we can close it again.
5622 */
5623 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_CLOSE);
5624 ssh2_pkt_adduint32(ssh, c->remoteid);
5625 ssh2_pkt_send(ssh);
5626 }
5627 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN_FAILURE) {
5628 unsigned i = ssh2_pkt_getuint32(ssh);
5629 struct ssh_channel *c;
5630 c = find234(ssh->channels, &i, ssh_channelfind);
5631 if (!c)
5632 continue; /* nonexistent channel */
5633 if (c->type != CHAN_SOCKDATA_DORMANT)
5634 continue; /* dunno why they're failing this */
5635
5636 logevent("Forwarded connection refused by server");
5637
5638 pfd_close(c->u.pfd.s);
5639
5640 del234(ssh->channels, c);
5641 sfree(c);
5642 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_REQUEST) {
5643 unsigned localid;
5644 char *type;
5645 int typelen, want_reply;
5646 struct ssh_channel *c;
5647
5648 localid = ssh2_pkt_getuint32(ssh);
5649 ssh2_pkt_getstring(ssh, &type, &typelen);
5650 want_reply = ssh2_pkt_getbool(ssh);
5651
5652 /*
5653 * First, check that the channel exists. Otherwise,
5654 * we can instantly disconnect with a rude message.
5655 */
5656 c = find234(ssh->channels, &localid, ssh_channelfind);
5657 if (!c) {
5658 char buf[80];
5659 sprintf(buf, "Received channel request for nonexistent"
5660 " channel %d", localid);
5661 logevent(buf);
5662 ssh2_pkt_init(ssh, SSH2_MSG_DISCONNECT);
5663 ssh2_pkt_adduint32(ssh, SSH2_DISCONNECT_BY_APPLICATION);
5664 ssh2_pkt_addstring(ssh, buf);
5665 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5666 ssh2_pkt_send(ssh);
5667 connection_fatal("%s", buf);
5668 ssh->state = SSH_STATE_CLOSED;
5669 crReturnV;
5670 }
5671
5672 /*
5673 * Having got the channel number, we now look at
5674 * the request type string to see if it's something
5675 * we recognise.
5676 */
5677 if (typelen == 11 && !memcmp(type, "exit-status", 11) &&
5678 c == ssh->mainchan) {
5679 /* We recognise "exit-status" on the primary channel. */
5680 char buf[100];
5681 ssh->exitcode = ssh2_pkt_getuint32(ssh);
5682 sprintf(buf, "Server sent command exit status %d",
5683 ssh->exitcode);
5684 logevent(buf);
5685 if (want_reply) {
5686 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_SUCCESS);
5687 ssh2_pkt_adduint32(ssh, c->remoteid);
5688 ssh2_pkt_send(ssh);
5689 }
5690 } else {
5691 /*
5692 * This is a channel request we don't know
5693 * about, so we now either ignore the request
5694 * or respond with CHANNEL_FAILURE, depending
5695 * on want_reply.
5696 */
5697 if (want_reply) {
5698 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_FAILURE);
5699 ssh2_pkt_adduint32(ssh, c->remoteid);
5700 ssh2_pkt_send(ssh);
5701 }
5702 }
5703 } else if (ssh->pktin.type == SSH2_MSG_GLOBAL_REQUEST) {
5704 char *type;
5705 int typelen, want_reply;
5706
5707 ssh2_pkt_getstring(ssh, &type, &typelen);
5708 want_reply = ssh2_pkt_getbool(ssh);
5709
5710 /*
5711 * We currently don't support any global requests
5712 * at all, so we either ignore the request or
5713 * respond with REQUEST_FAILURE, depending on
5714 * want_reply.
5715 */
5716 if (want_reply) {
5717 ssh2_pkt_init(ssh, SSH2_MSG_REQUEST_FAILURE);
5718 ssh2_pkt_send(ssh);
5719 }
5720 } else if (ssh->pktin.type == SSH2_MSG_CHANNEL_OPEN) {
5721 char *type;
5722 int typelen;
5723 char *error = NULL;
5724 struct ssh_channel *c;
5725 unsigned remid, winsize, pktsize;
5726 ssh2_pkt_getstring(ssh, &type, &typelen);
5727 c = smalloc(sizeof(struct ssh_channel));
5728 c->ssh = ssh;
5729
5730 remid = ssh2_pkt_getuint32(ssh);
5731 winsize = ssh2_pkt_getuint32(ssh);
5732 pktsize = ssh2_pkt_getuint32(ssh);
5733
5734 if (typelen == 3 && !memcmp(type, "x11", 3)) {
5735 if (!ssh->X11_fwd_enabled)
5736 error = "X11 forwarding is not enabled";
5737 else if (x11_init(&c->u.x11.s, cfg.x11_display, c,
5738 ssh->x11auth) != NULL) {
5739 error = "Unable to open an X11 connection";
5740 } else {
5741 c->type = CHAN_X11;
5742 }
5743 } else if (typelen == 15 &&
5744 !memcmp(type, "forwarded-tcpip", 15)) {
5745 struct ssh_rportfwd pf, *realpf;
5746 char *dummy;
5747 int dummylen;
5748 ssh2_pkt_getstring(ssh, &dummy, &dummylen);/* skip address */
5749 pf.sport = ssh2_pkt_getuint32(ssh);
5750 realpf = find234(ssh->rportfwds, &pf, NULL);
5751 if (realpf == NULL) {
5752 error = "Remote port is not recognised";
5753 } else {
5754 char *e = pfd_newconnect(&c->u.pfd.s, realpf->dhost,
5755 realpf->dport, c);
5756 logeventf(ssh, "Received remote port open request"
5757 " for %s:%d", realpf->dhost, realpf->dport);
5758 if (e != NULL) {
5759 logeventf(ssh, "Port open failed: %s", e);
5760 error = "Port open failed";
5761 } else {
5762 logevent("Forwarded port opened successfully");
5763 c->type = CHAN_SOCKDATA;
5764 }
5765 }
5766 } else if (typelen == 22 &&
5767 !memcmp(type, "auth-agent@openssh.com", 3)) {
5768 if (!ssh->agentfwd_enabled)
5769 error = "Agent forwarding is not enabled";
5770 else {
5771 c->type = CHAN_AGENT; /* identify channel type */
5772 c->u.a.lensofar = 0;
5773 }
5774 } else {
5775 error = "Unsupported channel type requested";
5776 }
5777
5778 c->remoteid = remid;
5779 if (error) {
5780 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE);
5781 ssh2_pkt_adduint32(ssh, c->remoteid);
5782 ssh2_pkt_adduint32(ssh, SSH2_OPEN_CONNECT_FAILED);
5783 ssh2_pkt_addstring(ssh, error);
5784 ssh2_pkt_addstring(ssh, "en"); /* language tag */
5785 ssh2_pkt_send(ssh);
5786 sfree(c);
5787 } else {
5788 c->localid = alloc_channel_id(ssh);
5789 c->closes = 0;
5790 c->v.v2.locwindow = OUR_V2_WINSIZE;
5791 c->v.v2.remwindow = winsize;
5792 c->v.v2.remmaxpkt = pktsize;
5793 bufchain_init(&c->v.v2.outbuffer);
5794 add234(ssh->channels, c);
5795 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
5796 ssh2_pkt_adduint32(ssh, c->remoteid);
5797 ssh2_pkt_adduint32(ssh, c->localid);
5798 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);
5799 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
5800 ssh2_pkt_send(ssh);
5801 }
5802 } else {
5803 bombout((ssh,"Strange packet received: type %d", ssh->pktin.type));
5804 crReturnV;
5805 }
5806 } else {
5807 /*
5808 * We have spare data. Add it to the channel buffer.
5809 */
5810 ssh2_add_channel_data(ssh->mainchan, in, inlen);
5811 s->try_send = TRUE;
5812 }
5813 if (s->try_send) {
5814 int i;
5815 struct ssh_channel *c;
5816 /*
5817 * Try to send data on all channels if we can.
5818 */
5819 for (i = 0; NULL != (c = index234(ssh->channels, i)); i++) {
5820 int bufsize = ssh2_try_send(c);
5821 if (bufsize == 0) {
5822 switch (c->type) {
5823 case CHAN_MAINSESSION:
5824 /* stdin need not receive an unthrottle
5825 * notification since it will be polled */
5826 break;
5827 case CHAN_X11:
5828 x11_unthrottle(c->u.x11.s);
5829 break;
5830 case CHAN_AGENT:
5831 /* agent sockets are request/response and need no
5832 * buffer management */
5833 break;
5834 case CHAN_SOCKDATA:
5835 pfd_unthrottle(c->u.pfd.s);
5836 break;
5837 }
5838 }
5839 }
5840 }
5841 }
5842
5843 crFinishV;
5844 }
5845
5846 /*
5847 * Handle the top-level SSH2 protocol.
5848 */
5849 static void ssh2_protocol(Ssh ssh, unsigned char *in, int inlen, int ispkt)
5850 {
5851 if (do_ssh2_transport(ssh, in, inlen, ispkt) == 0)
5852 return;
5853 do_ssh2_authconn(ssh, in, inlen, ispkt);
5854 }
5855
5856 /*
5857 * Called to set up the connection.
5858 *
5859 * Returns an error message, or NULL on success.
5860 */
5861 static char *ssh_init(void *frontend_handle, void **backend_handle,
5862 char *host, int port, char **realhost, int nodelay)
5863 {
5864 char *p;
5865 Ssh ssh;
5866
5867 ssh = smalloc(sizeof(*ssh));
5868 ssh->s = NULL;
5869 ssh->cipher = NULL;
5870 ssh->v1_cipher_ctx = NULL;
5871 ssh->crcda_ctx = NULL;
5872 ssh->cscipher = NULL;
5873 ssh->cs_cipher_ctx = NULL;
5874 ssh->sccipher = NULL;
5875 ssh->sc_cipher_ctx = NULL;
5876 ssh->csmac = NULL;
5877 ssh->cs_mac_ctx = NULL;
5878 ssh->scmac = NULL;
5879 ssh->sc_mac_ctx = NULL;
5880 ssh->cscomp = NULL;
5881 ssh->cs_comp_ctx = NULL;
5882 ssh->sccomp = NULL;
5883 ssh->sc_comp_ctx = NULL;
5884 ssh->kex = NULL;
5885 ssh->hostkey = NULL;
5886 ssh->exitcode = -1;
5887 ssh->state = SSH_STATE_PREPACKET;
5888 ssh->size_needed = FALSE;
5889 ssh->eof_needed = FALSE;
5890 ssh->ldisc = NULL;
5891 ssh->logctx = NULL;
5892 {
5893 static const struct Packet empty = { 0, 0, NULL, NULL, 0 };
5894 ssh->pktin = ssh->pktout = empty;
5895 }
5896 ssh->deferred_send_data = NULL;
5897 ssh->deferred_len = 0;
5898 ssh->deferred_size = 0;
5899 ssh->fallback_cmd = 0;
5900 ssh->pkt_ctx = 0;
5901 ssh->x11auth = NULL;
5902 ssh->v1_compressing = FALSE;
5903 ssh->v2_outgoing_sequence = 0;
5904 ssh->ssh1_rdpkt_crstate = 0;
5905 ssh->ssh2_rdpkt_crstate = 0;
5906 ssh->do_ssh_init_crstate = 0;
5907 ssh->ssh_gotdata_crstate = 0;
5908 ssh->ssh1_protocol_crstate = 0;
5909 ssh->do_ssh1_login_crstate = 0;
5910 ssh->do_ssh2_transport_crstate = 0;
5911 ssh->do_ssh2_authconn_crstate = 0;
5912 ssh->do_ssh_init_state = NULL;
5913 ssh->do_ssh1_login_state = NULL;
5914 ssh->do_ssh2_transport_state = NULL;
5915 ssh->do_ssh2_authconn_state = NULL;
5916 ssh->mainchan = NULL;
5917 ssh->throttled_all = 0;
5918 ssh->v1_stdout_throttling = 0;
5919
5920 *backend_handle = ssh;
5921
5922 #ifdef MSCRYPTOAPI
5923 if (crypto_startup() == 0)
5924 return "Microsoft high encryption pack not installed!";
5925 #endif
5926
5927 ssh->frontend = frontend_handle;
5928 ssh->term_width = cfg.width;
5929 ssh->term_height = cfg.height;
5930
5931 ssh->send_ok = 0;
5932 ssh->editing = 0;
5933 ssh->echoing = 0;
5934 ssh->v1_throttle_count = 0;
5935 ssh->overall_bufsize = 0;
5936 ssh->fallback_cmd = 0;
5937
5938 p = connect_to_host(ssh, host, port, realhost, nodelay);
5939 if (p != NULL)
5940 return p;
5941
5942 return NULL;
5943 }
5944
5945 /*
5946 * Called to send data down the Telnet connection.
5947 */
5948 static int ssh_send(void *handle, char *buf, int len)
5949 {
5950 Ssh ssh = (Ssh) handle;
5951
5952 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5953 return 0;
5954
5955 ssh->protocol(ssh, buf, len, 0);
5956
5957 return ssh_sendbuffer(ssh);
5958 }
5959
5960 /*
5961 * Called to query the current amount of buffered stdin data.
5962 */
5963 static int ssh_sendbuffer(void *handle)
5964 {
5965 Ssh ssh = (Ssh) handle;
5966 int override_value;
5967
5968 if (ssh == NULL || ssh->s == NULL || ssh->protocol == NULL)
5969 return 0;
5970
5971 /*
5972 * If the SSH socket itself has backed up, add the total backup
5973 * size on that to any individual buffer on the stdin channel.
5974 */
5975 override_value = 0;
5976 if (ssh->throttled_all)
5977 override_value = ssh->overall_bufsize;
5978
5979 if (ssh->version == 1) {
5980 return override_value;
5981 } else if (ssh->version == 2) {
5982 if (!ssh->mainchan || ssh->mainchan->closes > 0)
5983 return override_value;
5984 else
5985 return (override_value +
5986 bufchain_size(&ssh->mainchan->v.v2.outbuffer));
5987 }
5988
5989 return 0;
5990 }
5991
5992 /*
5993 * Called to set the size of the window from SSH's POV.
5994 */
5995 static void ssh_size(void *handle, int width, int height)
5996 {
5997 Ssh ssh = (Ssh) handle;
5998
5999 ssh->term_width = width;
6000 ssh->term_height = height;
6001
6002 switch (ssh->state) {
6003 case SSH_STATE_BEFORE_SIZE:
6004 case SSH_STATE_PREPACKET:
6005 case SSH_STATE_CLOSED:
6006 break; /* do nothing */
6007 case SSH_STATE_INTERMED:
6008 ssh->size_needed = TRUE; /* buffer for later */
6009 break;
6010 case SSH_STATE_SESSION:
6011 if (!cfg.nopty) {
6012 if (ssh->version == 1) {
6013 send_packet(ssh, SSH1_CMSG_WINDOW_SIZE,
6014 PKT_INT, ssh->term_height,
6015 PKT_INT, ssh->term_width,
6016 PKT_INT, 0, PKT_INT, 0, PKT_END);
6017 } else {
6018 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_REQUEST);
6019 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6020 ssh2_pkt_addstring(ssh, "window-change");
6021 ssh2_pkt_addbool(ssh, 0);
6022 ssh2_pkt_adduint32(ssh, ssh->term_width);
6023 ssh2_pkt_adduint32(ssh, ssh->term_height);
6024 ssh2_pkt_adduint32(ssh, 0);
6025 ssh2_pkt_adduint32(ssh, 0);
6026 ssh2_pkt_send(ssh);
6027 }
6028 }
6029 break;
6030 }
6031 }
6032
6033 /*
6034 * Send Telnet special codes. TS_EOF is useful for `plink', so you
6035 * can send an EOF and collect resulting output (e.g. `plink
6036 * hostname sort').
6037 */
6038 static void ssh_special(void *handle, Telnet_Special code)
6039 {
6040 Ssh ssh = (Ssh) handle;
6041
6042 if (code == TS_EOF) {
6043 if (ssh->state != SSH_STATE_SESSION) {
6044 /*
6045 * Buffer the EOF in case we are pre-SESSION, so we can
6046 * send it as soon as we reach SESSION.
6047 */
6048 if (code == TS_EOF)
6049 ssh->eof_needed = TRUE;
6050 return;
6051 }
6052 if (ssh->version == 1) {
6053 send_packet(ssh, SSH1_CMSG_EOF, PKT_END);
6054 } else {
6055 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_EOF);
6056 ssh2_pkt_adduint32(ssh, ssh->mainchan->remoteid);
6057 ssh2_pkt_send(ssh);
6058 }
6059 logevent("Sent EOF message");
6060 } else if (code == TS_PING) {
6061 if (ssh->state == SSH_STATE_CLOSED
6062 || ssh->state == SSH_STATE_PREPACKET) return;
6063 if (ssh->version == 1) {
6064 if (!(ssh->remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE))
6065 send_packet(ssh, SSH1_MSG_IGNORE, PKT_STR, "", PKT_END);
6066 } else {
6067 ssh2_pkt_init(ssh, SSH2_MSG_IGNORE);
6068 ssh2_pkt_addstring_start(ssh);
6069 ssh2_pkt_send(ssh);
6070 }
6071 } else {
6072 /* do nothing */
6073 }
6074 }
6075
6076 void *new_sock_channel(void *handle, Socket s)
6077 {
6078 Ssh ssh = (Ssh) handle;
6079 struct ssh_channel *c;
6080 c = smalloc(sizeof(struct ssh_channel));
6081 c->ssh = ssh;
6082
6083 if (c) {
6084 c->remoteid = -1; /* to be set when open confirmed */
6085 c->localid = alloc_channel_id(ssh);
6086 c->closes = 0;
6087 c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
6088 c->u.pfd.s = s;
6089 bufchain_init(&c->v.v2.outbuffer);
6090 add234(ssh->channels, c);
6091 }
6092 return c;
6093 }
6094
6095 /*
6096 * This is called when stdout/stderr (the entity to which
6097 * from_backend sends data) manages to clear some backlog.
6098 */
6099 void ssh_unthrottle(void *handle, int bufsize)
6100 {
6101 Ssh ssh = (Ssh) handle;
6102 if (ssh->version == 1) {
6103 if (ssh->v1_stdout_throttling && bufsize < SSH1_BUFFER_LIMIT) {
6104 ssh->v1_stdout_throttling = 0;
6105 ssh1_throttle(ssh, -1);
6106 }
6107 } else {
6108 if (ssh->mainchan && ssh->mainchan->closes == 0)
6109 ssh2_set_window(ssh->mainchan, OUR_V2_WINSIZE - bufsize);
6110 }
6111 }
6112
6113 void ssh_send_port_open(void *channel, char *hostname, int port, char *org)
6114 {
6115 struct ssh_channel *c = (struct ssh_channel *)channel;
6116 Ssh ssh = c->ssh;
6117
6118 logeventf(ssh, "Opening forwarded connection to %s:%d", hostname, port);
6119
6120 if (ssh->version == 1) {
6121 send_packet(ssh, SSH1_MSG_PORT_OPEN,
6122 PKT_INT, c->localid,
6123 PKT_STR, hostname,
6124 PKT_INT, port,
6125 //PKT_STR, <org:orgport>,
6126 PKT_END);
6127 } else {
6128 ssh2_pkt_init(ssh, SSH2_MSG_CHANNEL_OPEN);
6129 ssh2_pkt_addstring(ssh, "direct-tcpip");
6130 ssh2_pkt_adduint32(ssh, c->localid);
6131 c->v.v2.locwindow = OUR_V2_WINSIZE;
6132 ssh2_pkt_adduint32(ssh, c->v.v2.locwindow);/* our window size */
6133 ssh2_pkt_adduint32(ssh, 0x4000UL); /* our max pkt size */
6134 ssh2_pkt_addstring(ssh, hostname);
6135 ssh2_pkt_adduint32(ssh, port);
6136 /*
6137 * We make up values for the originator data; partly it's
6138 * too much hassle to keep track, and partly I'm not
6139 * convinced the server should be told details like that
6140 * about my local network configuration.
6141 */
6142 ssh2_pkt_addstring(ssh, "client-side-connection");
6143 ssh2_pkt_adduint32(ssh, 0);
6144 ssh2_pkt_send(ssh);
6145 }
6146 }
6147
6148
6149 static Socket ssh_socket(void *handle)
6150 {
6151 Ssh ssh = (Ssh) handle;
6152 return ssh->s;
6153 }
6154
6155 static int ssh_sendok(void *handle)
6156 {
6157 Ssh ssh = (Ssh) handle;
6158 return ssh->send_ok;
6159 }
6160
6161 static int ssh_ldisc(void *handle, int option)
6162 {
6163 Ssh ssh = (Ssh) handle;
6164 if (option == LD_ECHO)
6165 return ssh->echoing;
6166 if (option == LD_EDIT)
6167 return ssh->editing;
6168 return FALSE;
6169 }
6170
6171 static void ssh_provide_ldisc(void *handle, void *ldisc)
6172 {
6173 Ssh ssh = (Ssh) handle;
6174 ssh->ldisc = ldisc;
6175 }
6176
6177 static void ssh_provide_logctx(void *handle, void *logctx)
6178 {
6179 Ssh ssh = (Ssh) handle;
6180 ssh->logctx = logctx;
6181 }
6182
6183 static int ssh_return_exitcode(void *handle)
6184 {
6185 Ssh ssh = (Ssh) handle;
6186 return ssh->exitcode;
6187 }
6188
6189 /*
6190 * Gross hack: pscp will try to start SFTP but fall back to scp1 if
6191 * that fails. This variable is the means by which scp.c can reach
6192 * into the SSH code and find out which one it got.
6193 */
6194 extern int ssh_fallback_cmd(void *handle)
6195 {
6196 Ssh ssh = (Ssh) handle;
6197 return ssh->fallback_cmd;
6198 }
6199
6200 Backend ssh_backend = {
6201 ssh_init,
6202 ssh_send,
6203 ssh_sendbuffer,
6204 ssh_size,
6205 ssh_special,
6206 ssh_socket,
6207 ssh_return_exitcode,
6208 ssh_sendok,
6209 ssh_ldisc,
6210 ssh_provide_ldisc,
6211 ssh_provide_logctx,
6212 ssh_unthrottle,
6213 22
6214 };
Local modifications for Simon Tatham's `PuTTY' SSH client and terminal emulator