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1 | /* $OpenBSD: ssh-agent.c,v 1.48 2001/01/25 08:06:33 deraadt Exp $ */ | |
2 | ||
3 | /* | |
4 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
5 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
6 | * All rights reserved | |
7 | * The authentication agent program. | |
8 | * | |
9 | * As far as I am concerned, the code I have written for this software | |
10 | * can be used freely for any purpose. Any derived versions of this | |
11 | * software must be clearly marked as such, and if the derived work is | |
12 | * incompatible with the protocol description in the RFC file, it must be | |
13 | * called by a name other than "ssh" or "Secure Shell". | |
14 | * | |
15 | * SSH2 implementation, | |
16 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
17 | * | |
18 | * Redistribution and use in source and binary forms, with or without | |
19 | * modification, are permitted provided that the following conditions | |
20 | * are met: | |
21 | * 1. Redistributions of source code must retain the above copyright | |
22 | * notice, this list of conditions and the following disclaimer. | |
23 | * 2. Redistributions in binary form must reproduce the above copyright | |
24 | * notice, this list of conditions and the following disclaimer in the | |
25 | * documentation and/or other materials provided with the distribution. | |
26 | * | |
27 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
28 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
29 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
30 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
31 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
32 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
33 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
34 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
35 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
36 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
37 | */ | |
38 | ||
39 | #include "includes.h" | |
40 | RCSID("$OpenBSD: ssh-agent.c,v 1.48 2001/01/25 08:06:33 deraadt Exp $"); | |
41 | ||
42 | #include <openssl/evp.h> | |
43 | #include <openssl/md5.h> | |
44 | ||
45 | #include "ssh.h" | |
46 | #include "rsa.h" | |
47 | #include "buffer.h" | |
48 | #include "bufaux.h" | |
49 | #include "xmalloc.h" | |
50 | #include "packet.h" | |
51 | #include "getput.h" | |
52 | #include "mpaux.h" | |
53 | #include "key.h" | |
54 | #include "authfd.h" | |
55 | #include "cipher.h" | |
56 | #include "kex.h" | |
57 | #include "compat.h" | |
58 | #include "log.h" | |
59 | ||
60 | typedef struct { | |
61 | int fd; | |
62 | enum { | |
63 | AUTH_UNUSED, AUTH_SOCKET, AUTH_CONNECTION | |
64 | } type; | |
65 | Buffer input; | |
66 | Buffer output; | |
67 | } SocketEntry; | |
68 | ||
69 | u_int sockets_alloc = 0; | |
70 | SocketEntry *sockets = NULL; | |
71 | ||
72 | typedef struct { | |
73 | Key *key; | |
74 | char *comment; | |
75 | } Identity; | |
76 | ||
77 | typedef struct { | |
78 | int nentries; | |
79 | Identity *identities; | |
80 | } Idtab; | |
81 | ||
82 | /* private key table, one per protocol version */ | |
83 | Idtab idtable[3]; | |
84 | ||
85 | int max_fd = 0; | |
86 | ||
87 | /* pid of shell == parent of agent */ | |
88 | pid_t parent_pid = -1; | |
89 | ||
90 | /* pathname and directory for AUTH_SOCKET */ | |
91 | char socket_name[1024]; | |
92 | char socket_dir[1024]; | |
93 | ||
94 | #ifdef HAVE___PROGNAME | |
95 | extern char *__progname; | |
96 | #else | |
97 | char *__progname; | |
98 | #endif | |
99 | ||
100 | int prepare_select(fd_set **, fd_set **, int *); | |
101 | ||
102 | void | |
103 | idtab_init(void) | |
104 | { | |
105 | int i; | |
106 | for (i = 0; i <=2; i++){ | |
107 | idtable[i].identities = NULL; | |
108 | idtable[i].nentries = 0; | |
109 | } | |
110 | } | |
111 | ||
112 | /* return private key table for requested protocol version */ | |
113 | Idtab * | |
114 | idtab_lookup(int version) | |
115 | { | |
116 | if (version < 1 || version > 2) | |
117 | fatal("internal error, bad protocol version %d", version); | |
118 | return &idtable[version]; | |
119 | } | |
120 | ||
121 | /* return matching private key for given public key */ | |
122 | Key * | |
123 | lookup_private_key(Key *key, int *idx, int version) | |
124 | { | |
125 | int i; | |
126 | Idtab *tab = idtab_lookup(version); | |
127 | for (i = 0; i < tab->nentries; i++) { | |
128 | if (key_equal(key, tab->identities[i].key)) { | |
129 | if (idx != NULL) | |
130 | *idx = i; | |
131 | return tab->identities[i].key; | |
132 | } | |
133 | } | |
134 | return NULL; | |
135 | } | |
136 | ||
137 | /* send list of supported public keys to 'client' */ | |
138 | void | |
139 | process_request_identities(SocketEntry *e, int version) | |
140 | { | |
141 | Idtab *tab = idtab_lookup(version); | |
142 | Buffer msg; | |
143 | int i; | |
144 | ||
145 | buffer_init(&msg); | |
146 | buffer_put_char(&msg, (version == 1) ? | |
147 | SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); | |
148 | buffer_put_int(&msg, tab->nentries); | |
149 | for (i = 0; i < tab->nentries; i++) { | |
150 | Identity *id = &tab->identities[i]; | |
151 | if (id->key->type == KEY_RSA1) { | |
152 | buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); | |
153 | buffer_put_bignum(&msg, id->key->rsa->e); | |
154 | buffer_put_bignum(&msg, id->key->rsa->n); | |
155 | } else { | |
156 | u_char *blob; | |
157 | u_int blen; | |
158 | key_to_blob(id->key, &blob, &blen); | |
159 | buffer_put_string(&msg, blob, blen); | |
160 | xfree(blob); | |
161 | } | |
162 | buffer_put_cstring(&msg, id->comment); | |
163 | } | |
164 | buffer_put_int(&e->output, buffer_len(&msg)); | |
165 | buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); | |
166 | buffer_free(&msg); | |
167 | } | |
168 | ||
169 | /* ssh1 only */ | |
170 | void | |
171 | process_authentication_challenge1(SocketEntry *e) | |
172 | { | |
173 | Key *key, *private; | |
174 | BIGNUM *challenge; | |
175 | int i, len; | |
176 | Buffer msg; | |
177 | MD5_CTX md; | |
178 | u_char buf[32], mdbuf[16], session_id[16]; | |
179 | u_int response_type; | |
180 | ||
181 | buffer_init(&msg); | |
182 | key = key_new(KEY_RSA1); | |
183 | challenge = BN_new(); | |
184 | ||
185 | buffer_get_int(&e->input); /* ignored */ | |
186 | buffer_get_bignum(&e->input, key->rsa->e); | |
187 | buffer_get_bignum(&e->input, key->rsa->n); | |
188 | buffer_get_bignum(&e->input, challenge); | |
189 | ||
190 | /* Only protocol 1.1 is supported */ | |
191 | if (buffer_len(&e->input) == 0) | |
192 | goto failure; | |
193 | buffer_get(&e->input, (char *) session_id, 16); | |
194 | response_type = buffer_get_int(&e->input); | |
195 | if (response_type != 1) | |
196 | goto failure; | |
197 | ||
198 | private = lookup_private_key(key, NULL, 1); | |
199 | if (private != NULL) { | |
200 | /* Decrypt the challenge using the private key. */ | |
201 | rsa_private_decrypt(challenge, challenge, private->rsa); | |
202 | ||
203 | /* The response is MD5 of decrypted challenge plus session id. */ | |
204 | len = BN_num_bytes(challenge); | |
205 | if (len <= 0 || len > 32) { | |
206 | log("process_authentication_challenge: bad challenge length %d", len); | |
207 | goto failure; | |
208 | } | |
209 | memset(buf, 0, 32); | |
210 | BN_bn2bin(challenge, buf + 32 - len); | |
211 | MD5_Init(&md); | |
212 | MD5_Update(&md, buf, 32); | |
213 | MD5_Update(&md, session_id, 16); | |
214 | MD5_Final(mdbuf, &md); | |
215 | ||
216 | /* Send the response. */ | |
217 | buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); | |
218 | for (i = 0; i < 16; i++) | |
219 | buffer_put_char(&msg, mdbuf[i]); | |
220 | goto send; | |
221 | } | |
222 | ||
223 | failure: | |
224 | /* Unknown identity or protocol error. Send failure. */ | |
225 | buffer_put_char(&msg, SSH_AGENT_FAILURE); | |
226 | send: | |
227 | buffer_put_int(&e->output, buffer_len(&msg)); | |
228 | buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); | |
229 | key_free(key); | |
230 | BN_clear_free(challenge); | |
231 | buffer_free(&msg); | |
232 | } | |
233 | ||
234 | /* ssh2 only */ | |
235 | void | |
236 | process_sign_request2(SocketEntry *e) | |
237 | { | |
238 | extern int datafellows; | |
239 | Key *key, *private; | |
240 | u_char *blob, *data, *signature = NULL; | |
241 | u_int blen, dlen, slen = 0; | |
242 | int flags; | |
243 | Buffer msg; | |
244 | int ok = -1; | |
245 | ||
246 | datafellows = 0; | |
247 | ||
248 | blob = buffer_get_string(&e->input, &blen); | |
249 | data = buffer_get_string(&e->input, &dlen); | |
250 | ||
251 | flags = buffer_get_int(&e->input); | |
252 | if (flags & SSH_AGENT_OLD_SIGNATURE) | |
253 | datafellows = SSH_BUG_SIGBLOB; | |
254 | ||
255 | key = key_from_blob(blob, blen); | |
256 | if (key != NULL) { | |
257 | private = lookup_private_key(key, NULL, 2); | |
258 | if (private != NULL) | |
259 | ok = key_sign(private, &signature, &slen, data, dlen); | |
260 | } | |
261 | key_free(key); | |
262 | buffer_init(&msg); | |
263 | if (ok == 0) { | |
264 | buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); | |
265 | buffer_put_string(&msg, signature, slen); | |
266 | } else { | |
267 | buffer_put_char(&msg, SSH_AGENT_FAILURE); | |
268 | } | |
269 | buffer_put_int(&e->output, buffer_len(&msg)); | |
270 | buffer_append(&e->output, buffer_ptr(&msg), | |
271 | buffer_len(&msg)); | |
272 | buffer_free(&msg); | |
273 | xfree(data); | |
274 | xfree(blob); | |
275 | if (signature != NULL) | |
276 | xfree(signature); | |
277 | } | |
278 | ||
279 | /* shared */ | |
280 | void | |
281 | process_remove_identity(SocketEntry *e, int version) | |
282 | { | |
283 | Key *key = NULL, *private; | |
284 | u_char *blob; | |
285 | u_int blen; | |
286 | u_int bits; | |
287 | int success = 0; | |
288 | ||
289 | switch(version){ | |
290 | case 1: | |
291 | key = key_new(KEY_RSA1); | |
292 | bits = buffer_get_int(&e->input); | |
293 | buffer_get_bignum(&e->input, key->rsa->e); | |
294 | buffer_get_bignum(&e->input, key->rsa->n); | |
295 | ||
296 | if (bits != key_size(key)) | |
297 | log("Warning: identity keysize mismatch: actual %d, announced %d", | |
298 | key_size(key), bits); | |
299 | break; | |
300 | case 2: | |
301 | blob = buffer_get_string(&e->input, &blen); | |
302 | key = key_from_blob(blob, blen); | |
303 | xfree(blob); | |
304 | break; | |
305 | } | |
306 | if (key != NULL) { | |
307 | int idx; | |
308 | private = lookup_private_key(key, &idx, version); | |
309 | if (private != NULL) { | |
310 | /* | |
311 | * We have this key. Free the old key. Since we | |
312 | * don\'t want to leave empty slots in the middle of | |
313 | * the array, we actually free the key there and move | |
314 | * all the entries between the empty slot and the end | |
315 | * of the array. | |
316 | */ | |
317 | Idtab *tab = idtab_lookup(version); | |
318 | key_free(tab->identities[idx].key); | |
319 | xfree(tab->identities[idx].comment); | |
320 | if (tab->nentries < 1) | |
321 | fatal("process_remove_identity: " | |
322 | "internal error: tab->nentries %d", | |
323 | tab->nentries); | |
324 | if (idx != tab->nentries - 1) { | |
325 | int i; | |
326 | for (i = idx; i < tab->nentries - 1; i++) | |
327 | tab->identities[i] = tab->identities[i+1]; | |
328 | } | |
329 | tab->identities[tab->nentries - 1].key = NULL; | |
330 | tab->identities[tab->nentries - 1].comment = NULL; | |
331 | tab->nentries--; | |
332 | success = 1; | |
333 | } | |
334 | key_free(key); | |
335 | } | |
336 | buffer_put_int(&e->output, 1); | |
337 | buffer_put_char(&e->output, | |
338 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
339 | } | |
340 | ||
341 | void | |
342 | process_remove_all_identities(SocketEntry *e, int version) | |
343 | { | |
344 | u_int i; | |
345 | Idtab *tab = idtab_lookup(version); | |
346 | ||
347 | /* Loop over all identities and clear the keys. */ | |
348 | for (i = 0; i < tab->nentries; i++) { | |
349 | key_free(tab->identities[i].key); | |
350 | xfree(tab->identities[i].comment); | |
351 | } | |
352 | ||
353 | /* Mark that there are no identities. */ | |
354 | tab->nentries = 0; | |
355 | ||
356 | /* Send success. */ | |
357 | buffer_put_int(&e->output, 1); | |
358 | buffer_put_char(&e->output, SSH_AGENT_SUCCESS); | |
359 | return; | |
360 | } | |
361 | ||
362 | void | |
363 | generate_additional_parameters(RSA *rsa) | |
364 | { | |
365 | BIGNUM *aux; | |
366 | BN_CTX *ctx; | |
367 | /* Generate additional parameters */ | |
368 | aux = BN_new(); | |
369 | ctx = BN_CTX_new(); | |
370 | ||
371 | BN_sub(aux, rsa->q, BN_value_one()); | |
372 | BN_mod(rsa->dmq1, rsa->d, aux, ctx); | |
373 | ||
374 | BN_sub(aux, rsa->p, BN_value_one()); | |
375 | BN_mod(rsa->dmp1, rsa->d, aux, ctx); | |
376 | ||
377 | BN_clear_free(aux); | |
378 | BN_CTX_free(ctx); | |
379 | } | |
380 | ||
381 | void | |
382 | process_add_identity(SocketEntry *e, int version) | |
383 | { | |
384 | Key *k = NULL; | |
385 | char *type_name; | |
386 | char *comment; | |
387 | int type, success = 0; | |
388 | Idtab *tab = idtab_lookup(version); | |
389 | ||
390 | switch (version) { | |
391 | case 1: | |
392 | k = key_new_private(KEY_RSA1); | |
393 | buffer_get_int(&e->input); /* ignored */ | |
394 | buffer_get_bignum(&e->input, k->rsa->n); | |
395 | buffer_get_bignum(&e->input, k->rsa->e); | |
396 | buffer_get_bignum(&e->input, k->rsa->d); | |
397 | buffer_get_bignum(&e->input, k->rsa->iqmp); | |
398 | ||
399 | /* SSH and SSL have p and q swapped */ | |
400 | buffer_get_bignum(&e->input, k->rsa->q); /* p */ | |
401 | buffer_get_bignum(&e->input, k->rsa->p); /* q */ | |
402 | ||
403 | /* Generate additional parameters */ | |
404 | generate_additional_parameters(k->rsa); | |
405 | break; | |
406 | case 2: | |
407 | type_name = buffer_get_string(&e->input, NULL); | |
408 | type = key_type_from_name(type_name); | |
409 | xfree(type_name); | |
410 | switch(type) { | |
411 | case KEY_DSA: | |
412 | k = key_new_private(type); | |
413 | buffer_get_bignum2(&e->input, k->dsa->p); | |
414 | buffer_get_bignum2(&e->input, k->dsa->q); | |
415 | buffer_get_bignum2(&e->input, k->dsa->g); | |
416 | buffer_get_bignum2(&e->input, k->dsa->pub_key); | |
417 | buffer_get_bignum2(&e->input, k->dsa->priv_key); | |
418 | break; | |
419 | case KEY_RSA: | |
420 | k = key_new_private(type); | |
421 | buffer_get_bignum2(&e->input, k->rsa->n); | |
422 | buffer_get_bignum2(&e->input, k->rsa->e); | |
423 | buffer_get_bignum2(&e->input, k->rsa->d); | |
424 | buffer_get_bignum2(&e->input, k->rsa->iqmp); | |
425 | buffer_get_bignum2(&e->input, k->rsa->p); | |
426 | buffer_get_bignum2(&e->input, k->rsa->q); | |
427 | ||
428 | /* Generate additional parameters */ | |
429 | generate_additional_parameters(k->rsa); | |
430 | break; | |
431 | default: | |
432 | buffer_clear(&e->input); | |
433 | goto send; | |
434 | } | |
435 | break; | |
436 | } | |
437 | comment = buffer_get_string(&e->input, NULL); | |
438 | if (k == NULL) { | |
439 | xfree(comment); | |
440 | goto send; | |
441 | } | |
442 | success = 1; | |
443 | if (lookup_private_key(k, NULL, version) == NULL) { | |
444 | if (tab->nentries == 0) | |
445 | tab->identities = xmalloc(sizeof(Identity)); | |
446 | else | |
447 | tab->identities = xrealloc(tab->identities, | |
448 | (tab->nentries + 1) * sizeof(Identity)); | |
449 | tab->identities[tab->nentries].key = k; | |
450 | tab->identities[tab->nentries].comment = comment; | |
451 | /* Increment the number of identities. */ | |
452 | tab->nentries++; | |
453 | } else { | |
454 | key_free(k); | |
455 | xfree(comment); | |
456 | } | |
457 | send: | |
458 | buffer_put_int(&e->output, 1); | |
459 | buffer_put_char(&e->output, | |
460 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
461 | } | |
462 | ||
463 | /* dispatch incoming messages */ | |
464 | ||
465 | void | |
466 | process_message(SocketEntry *e) | |
467 | { | |
468 | u_int msg_len; | |
469 | u_int type; | |
470 | u_char *cp; | |
471 | if (buffer_len(&e->input) < 5) | |
472 | return; /* Incomplete message. */ | |
473 | cp = (u_char *) buffer_ptr(&e->input); | |
474 | msg_len = GET_32BIT(cp); | |
475 | if (msg_len > 256 * 1024) { | |
476 | shutdown(e->fd, SHUT_RDWR); | |
477 | close(e->fd); | |
478 | e->type = AUTH_UNUSED; | |
479 | return; | |
480 | } | |
481 | if (buffer_len(&e->input) < msg_len + 4) | |
482 | return; | |
483 | buffer_consume(&e->input, 4); | |
484 | type = buffer_get_char(&e->input); | |
485 | ||
486 | switch (type) { | |
487 | /* ssh1 */ | |
488 | case SSH_AGENTC_RSA_CHALLENGE: | |
489 | process_authentication_challenge1(e); | |
490 | break; | |
491 | case SSH_AGENTC_REQUEST_RSA_IDENTITIES: | |
492 | process_request_identities(e, 1); | |
493 | break; | |
494 | case SSH_AGENTC_ADD_RSA_IDENTITY: | |
495 | process_add_identity(e, 1); | |
496 | break; | |
497 | case SSH_AGENTC_REMOVE_RSA_IDENTITY: | |
498 | process_remove_identity(e, 1); | |
499 | break; | |
500 | case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: | |
501 | process_remove_all_identities(e, 1); | |
502 | break; | |
503 | /* ssh2 */ | |
504 | case SSH2_AGENTC_SIGN_REQUEST: | |
505 | process_sign_request2(e); | |
506 | break; | |
507 | case SSH2_AGENTC_REQUEST_IDENTITIES: | |
508 | process_request_identities(e, 2); | |
509 | break; | |
510 | case SSH2_AGENTC_ADD_IDENTITY: | |
511 | process_add_identity(e, 2); | |
512 | break; | |
513 | case SSH2_AGENTC_REMOVE_IDENTITY: | |
514 | process_remove_identity(e, 2); | |
515 | break; | |
516 | case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: | |
517 | process_remove_all_identities(e, 2); | |
518 | break; | |
519 | default: | |
520 | /* Unknown message. Respond with failure. */ | |
521 | error("Unknown message %d", type); | |
522 | buffer_clear(&e->input); | |
523 | buffer_put_int(&e->output, 1); | |
524 | buffer_put_char(&e->output, SSH_AGENT_FAILURE); | |
525 | break; | |
526 | } | |
527 | } | |
528 | ||
529 | void | |
530 | new_socket(int type, int fd) | |
531 | { | |
532 | u_int i, old_alloc; | |
533 | if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) | |
534 | error("fcntl O_NONBLOCK: %s", strerror(errno)); | |
535 | ||
536 | if (fd > max_fd) | |
537 | max_fd = fd; | |
538 | ||
539 | for (i = 0; i < sockets_alloc; i++) | |
540 | if (sockets[i].type == AUTH_UNUSED) { | |
541 | sockets[i].fd = fd; | |
542 | sockets[i].type = type; | |
543 | buffer_init(&sockets[i].input); | |
544 | buffer_init(&sockets[i].output); | |
545 | return; | |
546 | } | |
547 | old_alloc = sockets_alloc; | |
548 | sockets_alloc += 10; | |
549 | if (sockets) | |
550 | sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); | |
551 | else | |
552 | sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); | |
553 | for (i = old_alloc; i < sockets_alloc; i++) | |
554 | sockets[i].type = AUTH_UNUSED; | |
555 | sockets[old_alloc].type = type; | |
556 | sockets[old_alloc].fd = fd; | |
557 | buffer_init(&sockets[old_alloc].input); | |
558 | buffer_init(&sockets[old_alloc].output); | |
559 | } | |
560 | ||
561 | int | |
562 | prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl) | |
563 | { | |
564 | u_int i, sz; | |
565 | int n = 0; | |
566 | ||
567 | for (i = 0; i < sockets_alloc; i++) { | |
568 | switch (sockets[i].type) { | |
569 | case AUTH_SOCKET: | |
570 | case AUTH_CONNECTION: | |
571 | n = MAX(n, sockets[i].fd); | |
572 | break; | |
573 | case AUTH_UNUSED: | |
574 | break; | |
575 | default: | |
576 | fatal("Unknown socket type %d", sockets[i].type); | |
577 | break; | |
578 | } | |
579 | } | |
580 | ||
581 | sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); | |
582 | if (*fdrp == NULL || n > *fdl) { | |
583 | if (*fdrp) | |
584 | free(*fdrp); | |
585 | if (*fdwp) | |
586 | free(*fdwp); | |
587 | *fdrp = xmalloc(sz); | |
588 | *fdwp = xmalloc(sz); | |
589 | *fdl = n; | |
590 | } | |
591 | memset(*fdrp, 0, sz); | |
592 | memset(*fdwp, 0, sz); | |
593 | ||
594 | for (i = 0; i < sockets_alloc; i++) { | |
595 | switch (sockets[i].type) { | |
596 | case AUTH_SOCKET: | |
597 | case AUTH_CONNECTION: | |
598 | FD_SET(sockets[i].fd, *fdrp); | |
599 | if (buffer_len(&sockets[i].output) > 0) | |
600 | FD_SET(sockets[i].fd, *fdwp); | |
601 | break; | |
602 | default: | |
603 | break; | |
604 | } | |
605 | } | |
606 | return (1); | |
607 | } | |
608 | ||
609 | void | |
610 | after_select(fd_set *readset, fd_set *writeset) | |
611 | { | |
612 | u_int i; | |
613 | int len, sock; | |
614 | socklen_t slen; | |
615 | char buf[1024]; | |
616 | struct sockaddr_un sunaddr; | |
617 | ||
618 | for (i = 0; i < sockets_alloc; i++) | |
619 | switch (sockets[i].type) { | |
620 | case AUTH_UNUSED: | |
621 | break; | |
622 | case AUTH_SOCKET: | |
623 | if (FD_ISSET(sockets[i].fd, readset)) { | |
624 | slen = sizeof(sunaddr); | |
625 | sock = accept(sockets[i].fd, | |
626 | (struct sockaddr *) &sunaddr, &slen); | |
627 | if (sock < 0) { | |
628 | perror("accept from AUTH_SOCKET"); | |
629 | break; | |
630 | } | |
631 | new_socket(AUTH_CONNECTION, sock); | |
632 | } | |
633 | break; | |
634 | case AUTH_CONNECTION: | |
635 | if (buffer_len(&sockets[i].output) > 0 && | |
636 | FD_ISSET(sockets[i].fd, writeset)) { | |
637 | len = write(sockets[i].fd, | |
638 | buffer_ptr(&sockets[i].output), | |
639 | buffer_len(&sockets[i].output)); | |
640 | if (len <= 0) { | |
641 | shutdown(sockets[i].fd, SHUT_RDWR); | |
642 | close(sockets[i].fd); | |
643 | sockets[i].type = AUTH_UNUSED; | |
644 | buffer_free(&sockets[i].input); | |
645 | buffer_free(&sockets[i].output); | |
646 | break; | |
647 | } | |
648 | buffer_consume(&sockets[i].output, len); | |
649 | } | |
650 | if (FD_ISSET(sockets[i].fd, readset)) { | |
651 | len = read(sockets[i].fd, buf, sizeof(buf)); | |
652 | if (len <= 0) { | |
653 | shutdown(sockets[i].fd, SHUT_RDWR); | |
654 | close(sockets[i].fd); | |
655 | sockets[i].type = AUTH_UNUSED; | |
656 | buffer_free(&sockets[i].input); | |
657 | buffer_free(&sockets[i].output); | |
658 | break; | |
659 | } | |
660 | buffer_append(&sockets[i].input, buf, len); | |
661 | process_message(&sockets[i]); | |
662 | } | |
663 | break; | |
664 | default: | |
665 | fatal("Unknown type %d", sockets[i].type); | |
666 | } | |
667 | } | |
668 | ||
669 | void | |
670 | check_parent_exists(int sig) | |
671 | { | |
672 | int save_errno = errno; | |
673 | ||
674 | if (parent_pid != -1 && kill(parent_pid, 0) < 0) { | |
675 | /* printf("Parent has died - Authentication agent exiting.\n"); */ | |
676 | exit(1); | |
677 | } | |
678 | signal(SIGALRM, check_parent_exists); | |
679 | alarm(10); | |
680 | errno = save_errno; | |
681 | } | |
682 | ||
683 | void | |
684 | cleanup_socket(void) | |
685 | { | |
686 | if (socket_name[0]) | |
687 | unlink(socket_name); | |
688 | if (socket_dir[0]) | |
689 | rmdir(socket_dir); | |
690 | } | |
691 | ||
692 | void | |
693 | cleanup_exit(int i) | |
694 | { | |
695 | cleanup_socket(); | |
696 | exit(i); | |
697 | } | |
698 | ||
699 | void | |
700 | cleanup_handler(int sig) | |
701 | { | |
702 | cleanup_socket(); | |
703 | _exit(2); | |
704 | } | |
705 | ||
706 | void | |
707 | usage() | |
708 | { | |
709 | fprintf(stderr, "ssh-agent version %s\n", SSH_VERSION); | |
710 | fprintf(stderr, "Usage: %s [-c | -s] [-k] [command {args...]]\n", | |
711 | __progname); | |
712 | exit(1); | |
713 | } | |
714 | ||
715 | int | |
716 | main(int ac, char **av) | |
717 | { | |
718 | int sock, c_flag = 0, k_flag = 0, s_flag = 0, ch; | |
719 | struct sockaddr_un sunaddr; | |
720 | #ifdef HAVE_SETRLIMIT | |
721 | struct rlimit rlim; | |
722 | #endif | |
723 | pid_t pid; | |
724 | char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; | |
725 | extern int optind; | |
726 | fd_set *readsetp = NULL, *writesetp = NULL; | |
727 | ||
728 | __progname = get_progname(av[0]); | |
729 | init_rng(); | |
730 | ||
731 | #ifdef __GNU_LIBRARY__ | |
732 | while ((ch = getopt(ac, av, "+cks")) != -1) { | |
733 | #else /* __GNU_LIBRARY__ */ | |
734 | while ((ch = getopt(ac, av, "cks")) != -1) { | |
735 | #endif /* __GNU_LIBRARY__ */ | |
736 | switch (ch) { | |
737 | case 'c': | |
738 | if (s_flag) | |
739 | usage(); | |
740 | c_flag++; | |
741 | break; | |
742 | case 'k': | |
743 | k_flag++; | |
744 | break; | |
745 | case 's': | |
746 | if (c_flag) | |
747 | usage(); | |
748 | s_flag++; | |
749 | break; | |
750 | default: | |
751 | usage(); | |
752 | } | |
753 | } | |
754 | ac -= optind; | |
755 | av += optind; | |
756 | ||
757 | if (ac > 0 && (c_flag || k_flag || s_flag)) | |
758 | usage(); | |
759 | ||
760 | if (ac == 0 && !c_flag && !k_flag && !s_flag) { | |
761 | shell = getenv("SHELL"); | |
762 | if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) | |
763 | c_flag = 1; | |
764 | } | |
765 | if (k_flag) { | |
766 | pidstr = getenv(SSH_AGENTPID_ENV_NAME); | |
767 | if (pidstr == NULL) { | |
768 | fprintf(stderr, "%s not set, cannot kill agent\n", | |
769 | SSH_AGENTPID_ENV_NAME); | |
770 | exit(1); | |
771 | } | |
772 | pid = atoi(pidstr); | |
773 | if (pid < 1) { | |
774 | fprintf(stderr, "%s=\"%s\", which is not a good PID\n", | |
775 | SSH_AGENTPID_ENV_NAME, pidstr); | |
776 | exit(1); | |
777 | } | |
778 | if (kill(pid, SIGTERM) == -1) { | |
779 | perror("kill"); | |
780 | exit(1); | |
781 | } | |
782 | format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; | |
783 | printf(format, SSH_AUTHSOCKET_ENV_NAME); | |
784 | printf(format, SSH_AGENTPID_ENV_NAME); | |
785 | printf("echo Agent pid %d killed;\n", pid); | |
786 | exit(0); | |
787 | } | |
788 | parent_pid = getpid(); | |
789 | ||
790 | /* Create private directory for agent socket */ | |
791 | strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); | |
792 | if (mkdtemp(socket_dir) == NULL) { | |
793 | perror("mkdtemp: private socket dir"); | |
794 | exit(1); | |
795 | } | |
796 | snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir, | |
797 | parent_pid); | |
798 | ||
799 | /* | |
800 | * Create socket early so it will exist before command gets run from | |
801 | * the parent. | |
802 | */ | |
803 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
804 | if (sock < 0) { | |
805 | perror("socket"); | |
806 | cleanup_exit(1); | |
807 | } | |
808 | memset(&sunaddr, 0, sizeof(sunaddr)); | |
809 | sunaddr.sun_family = AF_UNIX; | |
810 | strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); | |
811 | if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { | |
812 | perror("bind"); | |
813 | cleanup_exit(1); | |
814 | } | |
815 | if (listen(sock, 5) < 0) { | |
816 | perror("listen"); | |
817 | cleanup_exit(1); | |
818 | } | |
819 | ||
820 | /* | |
821 | * Fork, and have the parent execute the command, if any, or present | |
822 | * the socket data. The child continues as the authentication agent. | |
823 | */ | |
824 | pid = fork(); | |
825 | if (pid == -1) { | |
826 | perror("fork"); | |
827 | exit(1); | |
828 | } | |
829 | if (pid != 0) { /* Parent - execute the given command. */ | |
830 | close(sock); | |
831 | snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid); | |
832 | if (ac == 0) { | |
833 | format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; | |
834 | printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, | |
835 | SSH_AUTHSOCKET_ENV_NAME); | |
836 | printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, | |
837 | SSH_AGENTPID_ENV_NAME); | |
838 | printf("echo Agent pid %d;\n", pid); | |
839 | exit(0); | |
840 | } | |
841 | if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || | |
842 | setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { | |
843 | perror("setenv"); | |
844 | exit(1); | |
845 | } | |
846 | execvp(av[0], av); | |
847 | perror(av[0]); | |
848 | exit(1); | |
849 | } | |
850 | close(0); | |
851 | close(1); | |
852 | close(2); | |
853 | ||
854 | #ifdef HAVE_SETRLIMIT | |
855 | /* deny core dumps, since memory contains unencrypted private keys */ | |
856 | rlim.rlim_cur = rlim.rlim_max = 0; | |
857 | if (setrlimit(RLIMIT_CORE, &rlim) < 0) { | |
858 | perror("setrlimit rlimit_core failed"); | |
859 | cleanup_exit(1); | |
860 | } | |
861 | #endif | |
862 | if (setsid() == -1) { | |
863 | perror("setsid"); | |
864 | cleanup_exit(1); | |
865 | } | |
866 | if (atexit(cleanup_socket) < 0) { | |
867 | perror("atexit"); | |
868 | cleanup_exit(1); | |
869 | } | |
870 | new_socket(AUTH_SOCKET, sock); | |
871 | if (ac > 0) { | |
872 | signal(SIGALRM, check_parent_exists); | |
873 | alarm(10); | |
874 | } | |
875 | idtab_init(); | |
876 | signal(SIGINT, SIG_IGN); | |
877 | signal(SIGPIPE, SIG_IGN); | |
878 | signal(SIGHUP, cleanup_handler); | |
879 | signal(SIGTERM, cleanup_handler); | |
880 | while (1) { | |
881 | prepare_select(&readsetp, &writesetp, &max_fd); | |
882 | if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { | |
883 | if (errno == EINTR) | |
884 | continue; | |
885 | exit(1); | |
886 | } | |
887 | after_select(readsetp, writesetp); | |
888 | } | |
889 | /* NOTREACHED */ | |
890 | } |