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1 | /* | |
2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * The authentication agent program. | |
6 | * | |
7 | * As far as I am concerned, the code I have written for this software | |
8 | * can be used freely for any purpose. Any derived versions of this | |
9 | * software must be clearly marked as such, and if the derived work is | |
10 | * incompatible with the protocol description in the RFC file, it must be | |
11 | * called by a name other than "ssh" or "Secure Shell". | |
12 | * | |
13 | * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. | |
14 | * | |
15 | * Redistribution and use in source and binary forms, with or without | |
16 | * modification, are permitted provided that the following conditions | |
17 | * are met: | |
18 | * 1. Redistributions of source code must retain the above copyright | |
19 | * notice, this list of conditions and the following disclaimer. | |
20 | * 2. Redistributions in binary form must reproduce the above copyright | |
21 | * notice, this list of conditions and the following disclaimer in the | |
22 | * documentation and/or other materials provided with the distribution. | |
23 | * | |
24 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
25 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
26 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
27 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
28 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
29 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
30 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
31 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
32 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
33 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
34 | */ | |
35 | ||
36 | #include "includes.h" | |
37 | RCSID("$OpenBSD: ssh-agent.c,v 1.84 2002/03/25 17:34:27 markus Exp $"); | |
38 | ||
39 | #if defined(HAVE_SYS_QUEUE_H) && !defined(HAVE_BOGUS_SYS_QUEUE_H) | |
40 | #include <sys/queue.h> | |
41 | #else | |
42 | #include "openbsd-compat/fake-queue.h" | |
43 | #endif | |
44 | ||
45 | #include <openssl/evp.h> | |
46 | #include <openssl/md5.h> | |
47 | ||
48 | #include "ssh.h" | |
49 | #include "rsa.h" | |
50 | #include "buffer.h" | |
51 | #include "bufaux.h" | |
52 | #include "xmalloc.h" | |
53 | #include "getput.h" | |
54 | #include "key.h" | |
55 | #include "authfd.h" | |
56 | #include "compat.h" | |
57 | #include "log.h" | |
58 | ||
59 | #ifdef SMARTCARD | |
60 | #include "scard.h" | |
61 | #endif | |
62 | ||
63 | typedef enum { | |
64 | AUTH_UNUSED, | |
65 | AUTH_SOCKET, | |
66 | AUTH_CONNECTION | |
67 | } sock_type; | |
68 | ||
69 | typedef struct { | |
70 | int fd; | |
71 | sock_type type; | |
72 | Buffer input; | |
73 | Buffer output; | |
74 | } SocketEntry; | |
75 | ||
76 | u_int sockets_alloc = 0; | |
77 | SocketEntry *sockets = NULL; | |
78 | ||
79 | typedef struct identity { | |
80 | TAILQ_ENTRY(identity) next; | |
81 | Key *key; | |
82 | char *comment; | |
83 | } Identity; | |
84 | ||
85 | typedef struct { | |
86 | int nentries; | |
87 | TAILQ_HEAD(idqueue, identity) idlist; | |
88 | } Idtab; | |
89 | ||
90 | /* private key table, one per protocol version */ | |
91 | Idtab idtable[3]; | |
92 | ||
93 | int max_fd = 0; | |
94 | ||
95 | /* pid of shell == parent of agent */ | |
96 | pid_t parent_pid = -1; | |
97 | ||
98 | /* pathname and directory for AUTH_SOCKET */ | |
99 | char socket_name[1024]; | |
100 | char socket_dir[1024]; | |
101 | ||
102 | #ifdef HAVE___PROGNAME | |
103 | extern char *__progname; | |
104 | #else | |
105 | char *__progname; | |
106 | #endif | |
107 | ||
108 | static void | |
109 | idtab_init(void) | |
110 | { | |
111 | int i; | |
112 | for (i = 0; i <=2; i++) { | |
113 | TAILQ_INIT(&idtable[i].idlist); | |
114 | idtable[i].nentries = 0; | |
115 | } | |
116 | } | |
117 | ||
118 | /* return private key table for requested protocol version */ | |
119 | static Idtab * | |
120 | idtab_lookup(int version) | |
121 | { | |
122 | if (version < 1 || version > 2) | |
123 | fatal("internal error, bad protocol version %d", version); | |
124 | return &idtable[version]; | |
125 | } | |
126 | ||
127 | /* return matching private key for given public key */ | |
128 | static Identity * | |
129 | lookup_identity(Key *key, int version) | |
130 | { | |
131 | Identity *id; | |
132 | ||
133 | Idtab *tab = idtab_lookup(version); | |
134 | TAILQ_FOREACH(id, &tab->idlist, next) { | |
135 | if (key_equal(key, id->key)) | |
136 | return (id); | |
137 | } | |
138 | return (NULL); | |
139 | } | |
140 | ||
141 | static void | |
142 | free_identity(Identity *id) | |
143 | { | |
144 | key_free(id->key); | |
145 | xfree(id->comment); | |
146 | xfree(id); | |
147 | } | |
148 | ||
149 | /* send list of supported public keys to 'client' */ | |
150 | static void | |
151 | process_request_identities(SocketEntry *e, int version) | |
152 | { | |
153 | Idtab *tab = idtab_lookup(version); | |
154 | Buffer msg; | |
155 | Identity *id; | |
156 | ||
157 | buffer_init(&msg); | |
158 | buffer_put_char(&msg, (version == 1) ? | |
159 | SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); | |
160 | buffer_put_int(&msg, tab->nentries); | |
161 | TAILQ_FOREACH(id, &tab->idlist, next) { | |
162 | if (id->key->type == KEY_RSA1) { | |
163 | buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); | |
164 | buffer_put_bignum(&msg, id->key->rsa->e); | |
165 | buffer_put_bignum(&msg, id->key->rsa->n); | |
166 | } else { | |
167 | u_char *blob; | |
168 | u_int blen; | |
169 | key_to_blob(id->key, &blob, &blen); | |
170 | buffer_put_string(&msg, blob, blen); | |
171 | xfree(blob); | |
172 | } | |
173 | buffer_put_cstring(&msg, id->comment); | |
174 | } | |
175 | buffer_put_int(&e->output, buffer_len(&msg)); | |
176 | buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); | |
177 | buffer_free(&msg); | |
178 | } | |
179 | ||
180 | /* ssh1 only */ | |
181 | static void | |
182 | process_authentication_challenge1(SocketEntry *e) | |
183 | { | |
184 | Identity *id; | |
185 | Key *key; | |
186 | BIGNUM *challenge; | |
187 | int i, len; | |
188 | Buffer msg; | |
189 | MD5_CTX md; | |
190 | u_char buf[32], mdbuf[16], session_id[16]; | |
191 | u_int response_type; | |
192 | ||
193 | buffer_init(&msg); | |
194 | key = key_new(KEY_RSA1); | |
195 | if ((challenge = BN_new()) == NULL) | |
196 | fatal("process_authentication_challenge1: BN_new failed"); | |
197 | ||
198 | buffer_get_int(&e->input); /* ignored */ | |
199 | buffer_get_bignum(&e->input, key->rsa->e); | |
200 | buffer_get_bignum(&e->input, key->rsa->n); | |
201 | buffer_get_bignum(&e->input, challenge); | |
202 | ||
203 | /* Only protocol 1.1 is supported */ | |
204 | if (buffer_len(&e->input) == 0) | |
205 | goto failure; | |
206 | buffer_get(&e->input, session_id, 16); | |
207 | response_type = buffer_get_int(&e->input); | |
208 | if (response_type != 1) | |
209 | goto failure; | |
210 | ||
211 | id = lookup_identity(key, 1); | |
212 | if (id != NULL) { | |
213 | Key *private = id->key; | |
214 | /* Decrypt the challenge using the private key. */ | |
215 | if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) | |
216 | goto failure; | |
217 | ||
218 | /* The response is MD5 of decrypted challenge plus session id. */ | |
219 | len = BN_num_bytes(challenge); | |
220 | if (len <= 0 || len > 32) { | |
221 | log("process_authentication_challenge: bad challenge length %d", len); | |
222 | goto failure; | |
223 | } | |
224 | memset(buf, 0, 32); | |
225 | BN_bn2bin(challenge, buf + 32 - len); | |
226 | MD5_Init(&md); | |
227 | MD5_Update(&md, buf, 32); | |
228 | MD5_Update(&md, session_id, 16); | |
229 | MD5_Final(mdbuf, &md); | |
230 | ||
231 | /* Send the response. */ | |
232 | buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); | |
233 | for (i = 0; i < 16; i++) | |
234 | buffer_put_char(&msg, mdbuf[i]); | |
235 | goto send; | |
236 | } | |
237 | ||
238 | failure: | |
239 | /* Unknown identity or protocol error. Send failure. */ | |
240 | buffer_put_char(&msg, SSH_AGENT_FAILURE); | |
241 | send: | |
242 | buffer_put_int(&e->output, buffer_len(&msg)); | |
243 | buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); | |
244 | key_free(key); | |
245 | BN_clear_free(challenge); | |
246 | buffer_free(&msg); | |
247 | } | |
248 | ||
249 | /* ssh2 only */ | |
250 | static void | |
251 | process_sign_request2(SocketEntry *e) | |
252 | { | |
253 | extern int datafellows; | |
254 | Key *key; | |
255 | u_char *blob, *data, *signature = NULL; | |
256 | u_int blen, dlen, slen = 0; | |
257 | int flags; | |
258 | Buffer msg; | |
259 | int ok = -1; | |
260 | ||
261 | datafellows = 0; | |
262 | ||
263 | blob = buffer_get_string(&e->input, &blen); | |
264 | data = buffer_get_string(&e->input, &dlen); | |
265 | ||
266 | flags = buffer_get_int(&e->input); | |
267 | if (flags & SSH_AGENT_OLD_SIGNATURE) | |
268 | datafellows = SSH_BUG_SIGBLOB; | |
269 | ||
270 | key = key_from_blob(blob, blen); | |
271 | if (key != NULL) { | |
272 | Identity *id = lookup_identity(key, 2); | |
273 | if (id != NULL) | |
274 | ok = key_sign(id->key, &signature, &slen, data, dlen); | |
275 | } | |
276 | key_free(key); | |
277 | buffer_init(&msg); | |
278 | if (ok == 0) { | |
279 | buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); | |
280 | buffer_put_string(&msg, signature, slen); | |
281 | } else { | |
282 | buffer_put_char(&msg, SSH_AGENT_FAILURE); | |
283 | } | |
284 | buffer_put_int(&e->output, buffer_len(&msg)); | |
285 | buffer_append(&e->output, buffer_ptr(&msg), | |
286 | buffer_len(&msg)); | |
287 | buffer_free(&msg); | |
288 | xfree(data); | |
289 | xfree(blob); | |
290 | if (signature != NULL) | |
291 | xfree(signature); | |
292 | } | |
293 | ||
294 | /* shared */ | |
295 | static void | |
296 | process_remove_identity(SocketEntry *e, int version) | |
297 | { | |
298 | Key *key = NULL; | |
299 | u_char *blob; | |
300 | u_int blen; | |
301 | u_int bits; | |
302 | int success = 0; | |
303 | ||
304 | switch (version) { | |
305 | case 1: | |
306 | key = key_new(KEY_RSA1); | |
307 | bits = buffer_get_int(&e->input); | |
308 | buffer_get_bignum(&e->input, key->rsa->e); | |
309 | buffer_get_bignum(&e->input, key->rsa->n); | |
310 | ||
311 | if (bits != key_size(key)) | |
312 | log("Warning: identity keysize mismatch: actual %d, announced %d", | |
313 | key_size(key), bits); | |
314 | break; | |
315 | case 2: | |
316 | blob = buffer_get_string(&e->input, &blen); | |
317 | key = key_from_blob(blob, blen); | |
318 | xfree(blob); | |
319 | break; | |
320 | } | |
321 | if (key != NULL) { | |
322 | Identity *id = lookup_identity(key, version); | |
323 | if (id != NULL) { | |
324 | /* | |
325 | * We have this key. Free the old key. Since we | |
326 | * don\'t want to leave empty slots in the middle of | |
327 | * the array, we actually free the key there and move | |
328 | * all the entries between the empty slot and the end | |
329 | * of the array. | |
330 | */ | |
331 | Idtab *tab = idtab_lookup(version); | |
332 | if (tab->nentries < 1) | |
333 | fatal("process_remove_identity: " | |
334 | "internal error: tab->nentries %d", | |
335 | tab->nentries); | |
336 | TAILQ_REMOVE(&tab->idlist, id, next); | |
337 | free_identity(id); | |
338 | tab->nentries--; | |
339 | success = 1; | |
340 | } | |
341 | key_free(key); | |
342 | } | |
343 | buffer_put_int(&e->output, 1); | |
344 | buffer_put_char(&e->output, | |
345 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
346 | } | |
347 | ||
348 | static void | |
349 | process_remove_all_identities(SocketEntry *e, int version) | |
350 | { | |
351 | Idtab *tab = idtab_lookup(version); | |
352 | Identity *id; | |
353 | ||
354 | /* Loop over all identities and clear the keys. */ | |
355 | for (id = TAILQ_FIRST(&tab->idlist); id; | |
356 | id = TAILQ_FIRST(&tab->idlist)) { | |
357 | TAILQ_REMOVE(&tab->idlist, id, next); | |
358 | free_identity(id); | |
359 | } | |
360 | ||
361 | /* Mark that there are no identities. */ | |
362 | tab->nentries = 0; | |
363 | ||
364 | /* Send success. */ | |
365 | buffer_put_int(&e->output, 1); | |
366 | buffer_put_char(&e->output, SSH_AGENT_SUCCESS); | |
367 | return; | |
368 | } | |
369 | ||
370 | static void | |
371 | process_add_identity(SocketEntry *e, int version) | |
372 | { | |
373 | Key *k = NULL; | |
374 | char *type_name; | |
375 | char *comment; | |
376 | int type, success = 0; | |
377 | Idtab *tab = idtab_lookup(version); | |
378 | ||
379 | switch (version) { | |
380 | case 1: | |
381 | k = key_new_private(KEY_RSA1); | |
382 | buffer_get_int(&e->input); /* ignored */ | |
383 | buffer_get_bignum(&e->input, k->rsa->n); | |
384 | buffer_get_bignum(&e->input, k->rsa->e); | |
385 | buffer_get_bignum(&e->input, k->rsa->d); | |
386 | buffer_get_bignum(&e->input, k->rsa->iqmp); | |
387 | ||
388 | /* SSH and SSL have p and q swapped */ | |
389 | buffer_get_bignum(&e->input, k->rsa->q); /* p */ | |
390 | buffer_get_bignum(&e->input, k->rsa->p); /* q */ | |
391 | ||
392 | /* Generate additional parameters */ | |
393 | rsa_generate_additional_parameters(k->rsa); | |
394 | break; | |
395 | case 2: | |
396 | type_name = buffer_get_string(&e->input, NULL); | |
397 | type = key_type_from_name(type_name); | |
398 | xfree(type_name); | |
399 | switch (type) { | |
400 | case KEY_DSA: | |
401 | k = key_new_private(type); | |
402 | buffer_get_bignum2(&e->input, k->dsa->p); | |
403 | buffer_get_bignum2(&e->input, k->dsa->q); | |
404 | buffer_get_bignum2(&e->input, k->dsa->g); | |
405 | buffer_get_bignum2(&e->input, k->dsa->pub_key); | |
406 | buffer_get_bignum2(&e->input, k->dsa->priv_key); | |
407 | break; | |
408 | case KEY_RSA: | |
409 | k = key_new_private(type); | |
410 | buffer_get_bignum2(&e->input, k->rsa->n); | |
411 | buffer_get_bignum2(&e->input, k->rsa->e); | |
412 | buffer_get_bignum2(&e->input, k->rsa->d); | |
413 | buffer_get_bignum2(&e->input, k->rsa->iqmp); | |
414 | buffer_get_bignum2(&e->input, k->rsa->p); | |
415 | buffer_get_bignum2(&e->input, k->rsa->q); | |
416 | ||
417 | /* Generate additional parameters */ | |
418 | rsa_generate_additional_parameters(k->rsa); | |
419 | break; | |
420 | default: | |
421 | buffer_clear(&e->input); | |
422 | goto send; | |
423 | } | |
424 | break; | |
425 | } | |
426 | comment = buffer_get_string(&e->input, NULL); | |
427 | if (k == NULL) { | |
428 | xfree(comment); | |
429 | goto send; | |
430 | } | |
431 | success = 1; | |
432 | if (lookup_identity(k, version) == NULL) { | |
433 | Identity *id = xmalloc(sizeof(Identity)); | |
434 | id->key = k; | |
435 | id->comment = comment; | |
436 | TAILQ_INSERT_TAIL(&tab->idlist, id, next); | |
437 | /* Increment the number of identities. */ | |
438 | tab->nentries++; | |
439 | } else { | |
440 | key_free(k); | |
441 | xfree(comment); | |
442 | } | |
443 | send: | |
444 | buffer_put_int(&e->output, 1); | |
445 | buffer_put_char(&e->output, | |
446 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
447 | } | |
448 | ||
449 | ||
450 | #ifdef SMARTCARD | |
451 | static void | |
452 | process_add_smartcard_key (SocketEntry *e) | |
453 | { | |
454 | Identity *id; | |
455 | Idtab *tab; | |
456 | Key **keys, *k; | |
457 | char *sc_reader_id = NULL, *pin; | |
458 | int i, version, success = 0; | |
459 | ||
460 | sc_reader_id = buffer_get_string(&e->input, NULL); | |
461 | pin = buffer_get_string(&e->input, NULL); | |
462 | keys = sc_get_keys(sc_reader_id, pin); | |
463 | xfree(sc_reader_id); | |
464 | xfree(pin); | |
465 | ||
466 | if (keys == NULL || keys[0] == NULL) { | |
467 | error("sc_get_keys failed"); | |
468 | goto send; | |
469 | } | |
470 | for (i = 0; keys[i] != NULL; i++) { | |
471 | k = keys[i]; | |
472 | version = k->type == KEY_RSA1 ? 1 : 2; | |
473 | tab = idtab_lookup(version); | |
474 | if (lookup_identity(k, version) == NULL) { | |
475 | id = xmalloc(sizeof(Identity)); | |
476 | id->key = k; | |
477 | id->comment = xstrdup("smartcard key"); | |
478 | TAILQ_INSERT_TAIL(&tab->idlist, id, next); | |
479 | tab->nentries++; | |
480 | success = 1; | |
481 | } else { | |
482 | key_free(k); | |
483 | } | |
484 | keys[i] = NULL; | |
485 | } | |
486 | xfree(keys); | |
487 | send: | |
488 | buffer_put_int(&e->output, 1); | |
489 | buffer_put_char(&e->output, | |
490 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
491 | } | |
492 | ||
493 | static void | |
494 | process_remove_smartcard_key(SocketEntry *e) | |
495 | { | |
496 | Identity *id; | |
497 | Idtab *tab; | |
498 | Key **keys, *k = NULL; | |
499 | char *sc_reader_id = NULL, *pin; | |
500 | int i, version, success = 0; | |
501 | ||
502 | sc_reader_id = buffer_get_string(&e->input, NULL); | |
503 | pin = buffer_get_string(&e->input, NULL); | |
504 | keys = sc_get_keys(sc_reader_id, pin); | |
505 | xfree(sc_reader_id); | |
506 | xfree(pin); | |
507 | ||
508 | if (keys == NULL || keys[0] == NULL) { | |
509 | error("sc_get_keys failed"); | |
510 | goto send; | |
511 | } | |
512 | for (i = 0; keys[i] != NULL; i++) { | |
513 | k = keys[i]; | |
514 | version = k->type == KEY_RSA1 ? 1 : 2; | |
515 | if ((id = lookup_identity(k, version)) != NULL) { | |
516 | tab = idtab_lookup(version); | |
517 | TAILQ_REMOVE(&tab->idlist, id, next); | |
518 | tab->nentries--; | |
519 | free_identity(id); | |
520 | success = 1; | |
521 | } | |
522 | key_free(k); | |
523 | keys[i] = NULL; | |
524 | } | |
525 | xfree(keys); | |
526 | send: | |
527 | buffer_put_int(&e->output, 1); | |
528 | buffer_put_char(&e->output, | |
529 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
530 | } | |
531 | #endif /* SMARTCARD */ | |
532 | ||
533 | /* dispatch incoming messages */ | |
534 | ||
535 | static void | |
536 | process_message(SocketEntry *e) | |
537 | { | |
538 | u_int msg_len; | |
539 | u_int type; | |
540 | u_char *cp; | |
541 | if (buffer_len(&e->input) < 5) | |
542 | return; /* Incomplete message. */ | |
543 | cp = buffer_ptr(&e->input); | |
544 | msg_len = GET_32BIT(cp); | |
545 | if (msg_len > 256 * 1024) { | |
546 | shutdown(e->fd, SHUT_RDWR); | |
547 | close(e->fd); | |
548 | e->type = AUTH_UNUSED; | |
549 | return; | |
550 | } | |
551 | if (buffer_len(&e->input) < msg_len + 4) | |
552 | return; | |
553 | buffer_consume(&e->input, 4); | |
554 | type = buffer_get_char(&e->input); | |
555 | ||
556 | debug("type %d", type); | |
557 | switch (type) { | |
558 | /* ssh1 */ | |
559 | case SSH_AGENTC_RSA_CHALLENGE: | |
560 | process_authentication_challenge1(e); | |
561 | break; | |
562 | case SSH_AGENTC_REQUEST_RSA_IDENTITIES: | |
563 | process_request_identities(e, 1); | |
564 | break; | |
565 | case SSH_AGENTC_ADD_RSA_IDENTITY: | |
566 | process_add_identity(e, 1); | |
567 | break; | |
568 | case SSH_AGENTC_REMOVE_RSA_IDENTITY: | |
569 | process_remove_identity(e, 1); | |
570 | break; | |
571 | case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: | |
572 | process_remove_all_identities(e, 1); | |
573 | break; | |
574 | /* ssh2 */ | |
575 | case SSH2_AGENTC_SIGN_REQUEST: | |
576 | process_sign_request2(e); | |
577 | break; | |
578 | case SSH2_AGENTC_REQUEST_IDENTITIES: | |
579 | process_request_identities(e, 2); | |
580 | break; | |
581 | case SSH2_AGENTC_ADD_IDENTITY: | |
582 | process_add_identity(e, 2); | |
583 | break; | |
584 | case SSH2_AGENTC_REMOVE_IDENTITY: | |
585 | process_remove_identity(e, 2); | |
586 | break; | |
587 | case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: | |
588 | process_remove_all_identities(e, 2); | |
589 | break; | |
590 | #ifdef SMARTCARD | |
591 | case SSH_AGENTC_ADD_SMARTCARD_KEY: | |
592 | process_add_smartcard_key(e); | |
593 | break; | |
594 | case SSH_AGENTC_REMOVE_SMARTCARD_KEY: | |
595 | process_remove_smartcard_key(e); | |
596 | break; | |
597 | #endif /* SMARTCARD */ | |
598 | default: | |
599 | /* Unknown message. Respond with failure. */ | |
600 | error("Unknown message %d", type); | |
601 | buffer_clear(&e->input); | |
602 | buffer_put_int(&e->output, 1); | |
603 | buffer_put_char(&e->output, SSH_AGENT_FAILURE); | |
604 | break; | |
605 | } | |
606 | } | |
607 | ||
608 | static void | |
609 | new_socket(sock_type type, int fd) | |
610 | { | |
611 | u_int i, old_alloc; | |
612 | if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) | |
613 | error("fcntl O_NONBLOCK: %s", strerror(errno)); | |
614 | ||
615 | if (fd > max_fd) | |
616 | max_fd = fd; | |
617 | ||
618 | for (i = 0; i < sockets_alloc; i++) | |
619 | if (sockets[i].type == AUTH_UNUSED) { | |
620 | sockets[i].fd = fd; | |
621 | sockets[i].type = type; | |
622 | buffer_init(&sockets[i].input); | |
623 | buffer_init(&sockets[i].output); | |
624 | return; | |
625 | } | |
626 | old_alloc = sockets_alloc; | |
627 | sockets_alloc += 10; | |
628 | if (sockets) | |
629 | sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); | |
630 | else | |
631 | sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); | |
632 | for (i = old_alloc; i < sockets_alloc; i++) | |
633 | sockets[i].type = AUTH_UNUSED; | |
634 | sockets[old_alloc].type = type; | |
635 | sockets[old_alloc].fd = fd; | |
636 | buffer_init(&sockets[old_alloc].input); | |
637 | buffer_init(&sockets[old_alloc].output); | |
638 | } | |
639 | ||
640 | static int | |
641 | prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) | |
642 | { | |
643 | u_int i, sz; | |
644 | int n = 0; | |
645 | ||
646 | for (i = 0; i < sockets_alloc; i++) { | |
647 | switch (sockets[i].type) { | |
648 | case AUTH_SOCKET: | |
649 | case AUTH_CONNECTION: | |
650 | n = MAX(n, sockets[i].fd); | |
651 | break; | |
652 | case AUTH_UNUSED: | |
653 | break; | |
654 | default: | |
655 | fatal("Unknown socket type %d", sockets[i].type); | |
656 | break; | |
657 | } | |
658 | } | |
659 | ||
660 | sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); | |
661 | if (*fdrp == NULL || sz > *nallocp) { | |
662 | if (*fdrp) | |
663 | xfree(*fdrp); | |
664 | if (*fdwp) | |
665 | xfree(*fdwp); | |
666 | *fdrp = xmalloc(sz); | |
667 | *fdwp = xmalloc(sz); | |
668 | *nallocp = sz; | |
669 | } | |
670 | if (n < *fdl) | |
671 | debug("XXX shrink: %d < %d", n, *fdl); | |
672 | *fdl = n; | |
673 | memset(*fdrp, 0, sz); | |
674 | memset(*fdwp, 0, sz); | |
675 | ||
676 | for (i = 0; i < sockets_alloc; i++) { | |
677 | switch (sockets[i].type) { | |
678 | case AUTH_SOCKET: | |
679 | case AUTH_CONNECTION: | |
680 | FD_SET(sockets[i].fd, *fdrp); | |
681 | if (buffer_len(&sockets[i].output) > 0) | |
682 | FD_SET(sockets[i].fd, *fdwp); | |
683 | break; | |
684 | default: | |
685 | break; | |
686 | } | |
687 | } | |
688 | return (1); | |
689 | } | |
690 | ||
691 | static void | |
692 | after_select(fd_set *readset, fd_set *writeset) | |
693 | { | |
694 | u_int i; | |
695 | int len, sock; | |
696 | socklen_t slen; | |
697 | char buf[1024]; | |
698 | struct sockaddr_un sunaddr; | |
699 | ||
700 | for (i = 0; i < sockets_alloc; i++) | |
701 | switch (sockets[i].type) { | |
702 | case AUTH_UNUSED: | |
703 | break; | |
704 | case AUTH_SOCKET: | |
705 | if (FD_ISSET(sockets[i].fd, readset)) { | |
706 | slen = sizeof(sunaddr); | |
707 | sock = accept(sockets[i].fd, | |
708 | (struct sockaddr *) &sunaddr, &slen); | |
709 | if (sock < 0) { | |
710 | error("accept from AUTH_SOCKET: %s", | |
711 | strerror(errno)); | |
712 | break; | |
713 | } | |
714 | new_socket(AUTH_CONNECTION, sock); | |
715 | } | |
716 | break; | |
717 | case AUTH_CONNECTION: | |
718 | if (buffer_len(&sockets[i].output) > 0 && | |
719 | FD_ISSET(sockets[i].fd, writeset)) { | |
720 | do { | |
721 | len = write(sockets[i].fd, | |
722 | buffer_ptr(&sockets[i].output), | |
723 | buffer_len(&sockets[i].output)); | |
724 | if (len == -1 && (errno == EAGAIN || | |
725 | errno == EINTR)) | |
726 | continue; | |
727 | break; | |
728 | } while (1); | |
729 | if (len <= 0) { | |
730 | shutdown(sockets[i].fd, SHUT_RDWR); | |
731 | close(sockets[i].fd); | |
732 | sockets[i].type = AUTH_UNUSED; | |
733 | buffer_free(&sockets[i].input); | |
734 | buffer_free(&sockets[i].output); | |
735 | break; | |
736 | } | |
737 | buffer_consume(&sockets[i].output, len); | |
738 | } | |
739 | if (FD_ISSET(sockets[i].fd, readset)) { | |
740 | do { | |
741 | len = read(sockets[i].fd, buf, sizeof(buf)); | |
742 | if (len == -1 && (errno == EAGAIN || | |
743 | errno == EINTR)) | |
744 | continue; | |
745 | break; | |
746 | } while (1); | |
747 | if (len <= 0) { | |
748 | shutdown(sockets[i].fd, SHUT_RDWR); | |
749 | close(sockets[i].fd); | |
750 | sockets[i].type = AUTH_UNUSED; | |
751 | buffer_free(&sockets[i].input); | |
752 | buffer_free(&sockets[i].output); | |
753 | break; | |
754 | } | |
755 | buffer_append(&sockets[i].input, buf, len); | |
756 | process_message(&sockets[i]); | |
757 | } | |
758 | break; | |
759 | default: | |
760 | fatal("Unknown type %d", sockets[i].type); | |
761 | } | |
762 | } | |
763 | ||
764 | static void | |
765 | cleanup_socket(void *p) | |
766 | { | |
767 | if (socket_name[0]) | |
768 | unlink(socket_name); | |
769 | if (socket_dir[0]) | |
770 | rmdir(socket_dir); | |
771 | } | |
772 | ||
773 | static void | |
774 | cleanup_exit(int i) | |
775 | { | |
776 | cleanup_socket(NULL); | |
777 | exit(i); | |
778 | } | |
779 | ||
780 | static void | |
781 | cleanup_handler(int sig) | |
782 | { | |
783 | cleanup_socket(NULL); | |
784 | _exit(2); | |
785 | } | |
786 | ||
787 | static void | |
788 | check_parent_exists(int sig) | |
789 | { | |
790 | int save_errno = errno; | |
791 | ||
792 | if (parent_pid != -1 && kill(parent_pid, 0) < 0) { | |
793 | /* printf("Parent has died - Authentication agent exiting.\n"); */ | |
794 | cleanup_handler(sig); /* safe */ | |
795 | } | |
796 | signal(SIGALRM, check_parent_exists); | |
797 | alarm(10); | |
798 | errno = save_errno; | |
799 | } | |
800 | ||
801 | static void | |
802 | usage(void) | |
803 | { | |
804 | fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", | |
805 | __progname); | |
806 | fprintf(stderr, "Options:\n"); | |
807 | fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); | |
808 | fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); | |
809 | fprintf(stderr, " -k Kill the current agent.\n"); | |
810 | fprintf(stderr, " -d Debug mode.\n"); | |
811 | exit(1); | |
812 | } | |
813 | ||
814 | int | |
815 | main(int ac, char **av) | |
816 | { | |
817 | int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc; | |
818 | struct sockaddr_un sunaddr; | |
819 | #ifdef HAVE_SETRLIMIT | |
820 | struct rlimit rlim; | |
821 | #endif | |
822 | #ifdef HAVE_CYGWIN | |
823 | int prev_mask; | |
824 | #endif | |
825 | pid_t pid; | |
826 | char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; | |
827 | extern int optind; | |
828 | fd_set *readsetp = NULL, *writesetp = NULL; | |
829 | ||
830 | SSLeay_add_all_algorithms(); | |
831 | ||
832 | __progname = get_progname(av[0]); | |
833 | init_rng(); | |
834 | seed_rng(); | |
835 | ||
836 | #ifdef __GNU_LIBRARY__ | |
837 | while ((ch = getopt(ac, av, "+cdks")) != -1) { | |
838 | #else /* __GNU_LIBRARY__ */ | |
839 | while ((ch = getopt(ac, av, "cdks")) != -1) { | |
840 | #endif /* __GNU_LIBRARY__ */ | |
841 | switch (ch) { | |
842 | case 'c': | |
843 | if (s_flag) | |
844 | usage(); | |
845 | c_flag++; | |
846 | break; | |
847 | case 'k': | |
848 | k_flag++; | |
849 | break; | |
850 | case 's': | |
851 | if (c_flag) | |
852 | usage(); | |
853 | s_flag++; | |
854 | break; | |
855 | case 'd': | |
856 | if (d_flag) | |
857 | usage(); | |
858 | d_flag++; | |
859 | break; | |
860 | default: | |
861 | usage(); | |
862 | } | |
863 | } | |
864 | ac -= optind; | |
865 | av += optind; | |
866 | ||
867 | if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) | |
868 | usage(); | |
869 | ||
870 | if (ac == 0 && !c_flag && !k_flag && !s_flag && !d_flag) { | |
871 | shell = getenv("SHELL"); | |
872 | if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) | |
873 | c_flag = 1; | |
874 | } | |
875 | if (k_flag) { | |
876 | pidstr = getenv(SSH_AGENTPID_ENV_NAME); | |
877 | if (pidstr == NULL) { | |
878 | fprintf(stderr, "%s not set, cannot kill agent\n", | |
879 | SSH_AGENTPID_ENV_NAME); | |
880 | exit(1); | |
881 | } | |
882 | pid = atoi(pidstr); | |
883 | if (pid < 1) { | |
884 | fprintf(stderr, "%s=\"%s\", which is not a good PID\n", | |
885 | SSH_AGENTPID_ENV_NAME, pidstr); | |
886 | exit(1); | |
887 | } | |
888 | if (kill(pid, SIGTERM) == -1) { | |
889 | perror("kill"); | |
890 | exit(1); | |
891 | } | |
892 | format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; | |
893 | printf(format, SSH_AUTHSOCKET_ENV_NAME); | |
894 | printf(format, SSH_AGENTPID_ENV_NAME); | |
895 | printf("echo Agent pid %d killed;\n", pid); | |
896 | exit(0); | |
897 | } | |
898 | parent_pid = getpid(); | |
899 | ||
900 | /* Create private directory for agent socket */ | |
901 | strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); | |
902 | if (mkdtemp(socket_dir) == NULL) { | |
903 | perror("mkdtemp: private socket dir"); | |
904 | exit(1); | |
905 | } | |
906 | snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir, | |
907 | parent_pid); | |
908 | ||
909 | /* | |
910 | * Create socket early so it will exist before command gets run from | |
911 | * the parent. | |
912 | */ | |
913 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
914 | if (sock < 0) { | |
915 | perror("socket"); | |
916 | cleanup_exit(1); | |
917 | } | |
918 | memset(&sunaddr, 0, sizeof(sunaddr)); | |
919 | sunaddr.sun_family = AF_UNIX; | |
920 | strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); | |
921 | #ifdef HAVE_CYGWIN | |
922 | prev_mask = umask(0177); | |
923 | #endif | |
924 | if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { | |
925 | perror("bind"); | |
926 | #ifdef HAVE_CYGWIN | |
927 | umask(prev_mask); | |
928 | #endif | |
929 | cleanup_exit(1); | |
930 | } | |
931 | #ifdef HAVE_CYGWIN | |
932 | umask(prev_mask); | |
933 | #endif | |
934 | if (listen(sock, 5) < 0) { | |
935 | perror("listen"); | |
936 | cleanup_exit(1); | |
937 | } | |
938 | ||
939 | /* | |
940 | * Fork, and have the parent execute the command, if any, or present | |
941 | * the socket data. The child continues as the authentication agent. | |
942 | */ | |
943 | if (d_flag) { | |
944 | log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); | |
945 | format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; | |
946 | printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, | |
947 | SSH_AUTHSOCKET_ENV_NAME); | |
948 | printf("echo Agent pid %d;\n", parent_pid); | |
949 | goto skip; | |
950 | } | |
951 | pid = fork(); | |
952 | if (pid == -1) { | |
953 | perror("fork"); | |
954 | cleanup_exit(1); | |
955 | } | |
956 | if (pid != 0) { /* Parent - execute the given command. */ | |
957 | close(sock); | |
958 | snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid); | |
959 | if (ac == 0) { | |
960 | format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; | |
961 | printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, | |
962 | SSH_AUTHSOCKET_ENV_NAME); | |
963 | printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, | |
964 | SSH_AGENTPID_ENV_NAME); | |
965 | printf("echo Agent pid %d;\n", pid); | |
966 | exit(0); | |
967 | } | |
968 | if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || | |
969 | setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { | |
970 | perror("setenv"); | |
971 | exit(1); | |
972 | } | |
973 | execvp(av[0], av); | |
974 | perror(av[0]); | |
975 | exit(1); | |
976 | } | |
977 | /* child */ | |
978 | log_init(__progname, SYSLOG_LEVEL_INFO, SYSLOG_FACILITY_AUTH, 0); | |
979 | ||
980 | if (setsid() == -1) { | |
981 | error("setsid: %s", strerror(errno)); | |
982 | cleanup_exit(1); | |
983 | } | |
984 | ||
985 | (void)chdir("/"); | |
986 | close(0); | |
987 | close(1); | |
988 | close(2); | |
989 | ||
990 | #ifdef HAVE_SETRLIMIT | |
991 | /* deny core dumps, since memory contains unencrypted private keys */ | |
992 | rlim.rlim_cur = rlim.rlim_max = 0; | |
993 | if (setrlimit(RLIMIT_CORE, &rlim) < 0) { | |
994 | error("setrlimit RLIMIT_CORE: %s", strerror(errno)); | |
995 | cleanup_exit(1); | |
996 | } | |
997 | #endif | |
998 | ||
999 | skip: | |
1000 | fatal_add_cleanup(cleanup_socket, NULL); | |
1001 | new_socket(AUTH_SOCKET, sock); | |
1002 | if (ac > 0) { | |
1003 | signal(SIGALRM, check_parent_exists); | |
1004 | alarm(10); | |
1005 | } | |
1006 | idtab_init(); | |
1007 | if (!d_flag) | |
1008 | signal(SIGINT, SIG_IGN); | |
1009 | signal(SIGPIPE, SIG_IGN); | |
1010 | signal(SIGHUP, cleanup_handler); | |
1011 | signal(SIGTERM, cleanup_handler); | |
1012 | nalloc = 0; | |
1013 | ||
1014 | while (1) { | |
1015 | prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); | |
1016 | if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { | |
1017 | if (errno == EINTR) | |
1018 | continue; | |
1019 | fatal("select: %s", strerror(errno)); | |
1020 | } | |
1021 | after_select(readsetp, writesetp); | |
1022 | } | |
1023 | /* NOTREACHED */ | |
1024 | } |