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1 | /* $OpenBSD: ssh-agent.c,v 1.40 2000/11/14 23:48:55 markus 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 1.40 2000/11/14 23:48:55 markus Exp $"); | |
41 | ||
42 | #include "ssh.h" | |
43 | #include "rsa.h" | |
44 | #include "buffer.h" | |
45 | #include "bufaux.h" | |
46 | #include "xmalloc.h" | |
47 | #include "packet.h" | |
48 | #include "getput.h" | |
49 | #include "mpaux.h" | |
50 | ||
51 | #include <openssl/evp.h> | |
52 | #include <openssl/md5.h> | |
53 | #include <openssl/dsa.h> | |
54 | #include <openssl/rsa.h> | |
55 | #include "key.h" | |
56 | #include "authfd.h" | |
57 | #include "kex.h" | |
58 | #include "compat.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 | unsigned 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 | void | |
101 | idtab_init(void) | |
102 | { | |
103 | int i; | |
104 | for (i = 0; i <=2; i++){ | |
105 | idtable[i].identities = NULL; | |
106 | idtable[i].nentries = 0; | |
107 | } | |
108 | } | |
109 | ||
110 | /* return private key table for requested protocol version */ | |
111 | Idtab * | |
112 | idtab_lookup(int version) | |
113 | { | |
114 | if (version < 1 || version > 2) | |
115 | fatal("internal error, bad protocol version %d", version); | |
116 | return &idtable[version]; | |
117 | } | |
118 | ||
119 | /* return matching private key for given public key */ | |
120 | Key * | |
121 | lookup_private_key(Key *key, int *idx, int version) | |
122 | { | |
123 | int i; | |
124 | Idtab *tab = idtab_lookup(version); | |
125 | for (i = 0; i < tab->nentries; i++) { | |
126 | if (key_equal(key, tab->identities[i].key)) { | |
127 | if (idx != NULL) | |
128 | *idx = i; | |
129 | return tab->identities[i].key; | |
130 | } | |
131 | } | |
132 | return NULL; | |
133 | } | |
134 | ||
135 | /* send list of supported public keys to 'client' */ | |
136 | void | |
137 | process_request_identities(SocketEntry *e, int version) | |
138 | { | |
139 | Idtab *tab = idtab_lookup(version); | |
140 | Buffer msg; | |
141 | int i; | |
142 | ||
143 | buffer_init(&msg); | |
144 | buffer_put_char(&msg, (version == 1) ? | |
145 | SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); | |
146 | buffer_put_int(&msg, tab->nentries); | |
147 | for (i = 0; i < tab->nentries; i++) { | |
148 | Identity *id = &tab->identities[i]; | |
149 | if (id->key->type == KEY_RSA1) { | |
150 | buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); | |
151 | buffer_put_bignum(&msg, id->key->rsa->e); | |
152 | buffer_put_bignum(&msg, id->key->rsa->n); | |
153 | } else { | |
154 | unsigned char *blob; | |
155 | unsigned int blen; | |
156 | key_to_blob(id->key, &blob, &blen); | |
157 | buffer_put_string(&msg, blob, blen); | |
158 | xfree(blob); | |
159 | } | |
160 | buffer_put_cstring(&msg, id->comment); | |
161 | } | |
162 | buffer_put_int(&e->output, buffer_len(&msg)); | |
163 | buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); | |
164 | buffer_free(&msg); | |
165 | } | |
166 | ||
167 | /* ssh1 only */ | |
168 | void | |
169 | process_authentication_challenge1(SocketEntry *e) | |
170 | { | |
171 | Key *key, *private; | |
172 | BIGNUM *challenge; | |
173 | int i, len; | |
174 | Buffer msg; | |
175 | MD5_CTX md; | |
176 | unsigned char buf[32], mdbuf[16], session_id[16]; | |
177 | unsigned int response_type; | |
178 | ||
179 | buffer_init(&msg); | |
180 | key = key_new(KEY_RSA1); | |
181 | challenge = BN_new(); | |
182 | ||
183 | buffer_get_int(&e->input); /* ignored */ | |
184 | buffer_get_bignum(&e->input, key->rsa->e); | |
185 | buffer_get_bignum(&e->input, key->rsa->n); | |
186 | buffer_get_bignum(&e->input, challenge); | |
187 | ||
188 | /* Only protocol 1.1 is supported */ | |
189 | if (buffer_len(&e->input) == 0) | |
190 | goto failure; | |
191 | buffer_get(&e->input, (char *) session_id, 16); | |
192 | response_type = buffer_get_int(&e->input); | |
193 | if (response_type != 1) | |
194 | goto failure; | |
195 | ||
196 | private = lookup_private_key(key, NULL, 1); | |
197 | if (private != NULL) { | |
198 | /* Decrypt the challenge using the private key. */ | |
199 | rsa_private_decrypt(challenge, challenge, private->rsa); | |
200 | ||
201 | /* The response is MD5 of decrypted challenge plus session id. */ | |
202 | len = BN_num_bytes(challenge); | |
203 | if (len <= 0 || len > 32) { | |
204 | log("process_authentication_challenge: bad challenge length %d", len); | |
205 | goto failure; | |
206 | } | |
207 | memset(buf, 0, 32); | |
208 | BN_bn2bin(challenge, buf + 32 - len); | |
209 | MD5_Init(&md); | |
210 | MD5_Update(&md, buf, 32); | |
211 | MD5_Update(&md, session_id, 16); | |
212 | MD5_Final(mdbuf, &md); | |
213 | ||
214 | /* Send the response. */ | |
215 | buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); | |
216 | for (i = 0; i < 16; i++) | |
217 | buffer_put_char(&msg, mdbuf[i]); | |
218 | goto send; | |
219 | } | |
220 | ||
221 | failure: | |
222 | /* Unknown identity or protocol error. Send failure. */ | |
223 | buffer_put_char(&msg, SSH_AGENT_FAILURE); | |
224 | send: | |
225 | buffer_put_int(&e->output, buffer_len(&msg)); | |
226 | buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); | |
227 | key_free(key); | |
228 | BN_clear_free(challenge); | |
229 | buffer_free(&msg); | |
230 | } | |
231 | ||
232 | /* ssh2 only */ | |
233 | void | |
234 | process_sign_request2(SocketEntry *e) | |
235 | { | |
236 | extern int datafellows; | |
237 | Key *key, *private; | |
238 | unsigned char *blob, *data, *signature = NULL; | |
239 | unsigned int blen, dlen, slen = 0; | |
240 | int flags; | |
241 | Buffer msg; | |
242 | int ok = -1; | |
243 | ||
244 | datafellows = 0; | |
245 | ||
246 | blob = buffer_get_string(&e->input, &blen); | |
247 | data = buffer_get_string(&e->input, &dlen); | |
248 | ||
249 | flags = buffer_get_int(&e->input); | |
250 | if (flags & SSH_AGENT_OLD_SIGNATURE) | |
251 | datafellows = SSH_BUG_SIGBLOB; | |
252 | ||
253 | key = key_from_blob(blob, blen); | |
254 | if (key != NULL) { | |
255 | private = lookup_private_key(key, NULL, 2); | |
256 | if (private != NULL) | |
257 | ok = key_sign(private, &signature, &slen, data, dlen); | |
258 | } | |
259 | key_free(key); | |
260 | buffer_init(&msg); | |
261 | if (ok == 0) { | |
262 | buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); | |
263 | buffer_put_string(&msg, signature, slen); | |
264 | } else { | |
265 | buffer_put_char(&msg, SSH_AGENT_FAILURE); | |
266 | } | |
267 | buffer_put_int(&e->output, buffer_len(&msg)); | |
268 | buffer_append(&e->output, buffer_ptr(&msg), | |
269 | buffer_len(&msg)); | |
270 | buffer_free(&msg); | |
271 | xfree(data); | |
272 | xfree(blob); | |
273 | if (signature != NULL) | |
274 | xfree(signature); | |
275 | } | |
276 | ||
277 | /* shared */ | |
278 | void | |
279 | process_remove_identity(SocketEntry *e, int version) | |
280 | { | |
281 | Key *key = NULL, *private; | |
282 | unsigned char *blob; | |
283 | unsigned int blen; | |
284 | unsigned int bits; | |
285 | int success = 0; | |
286 | ||
287 | switch(version){ | |
288 | case 1: | |
289 | key = key_new(KEY_RSA1); | |
290 | bits = buffer_get_int(&e->input); | |
291 | buffer_get_bignum(&e->input, key->rsa->e); | |
292 | buffer_get_bignum(&e->input, key->rsa->n); | |
293 | ||
294 | if (bits != key_size(key)) | |
295 | log("Warning: identity keysize mismatch: actual %d, announced %d", | |
296 | key_size(key), bits); | |
297 | break; | |
298 | case 2: | |
299 | blob = buffer_get_string(&e->input, &blen); | |
300 | key = key_from_blob(blob, blen); | |
301 | xfree(blob); | |
302 | break; | |
303 | } | |
304 | if (key != NULL) { | |
305 | int idx; | |
306 | private = lookup_private_key(key, &idx, version); | |
307 | if (private != NULL) { | |
308 | /* | |
309 | * We have this key. Free the old key. Since we | |
310 | * don\'t want to leave empty slots in the middle of | |
311 | * the array, we actually free the key there and move | |
312 | * all the entries between the empty slot and the end | |
313 | * of the array. | |
314 | */ | |
315 | Idtab *tab = idtab_lookup(version); | |
316 | key_free(tab->identities[idx].key); | |
317 | xfree(tab->identities[idx].comment); | |
318 | if (tab->nentries < 1) | |
319 | fatal("process_remove_identity: " | |
320 | "internal error: tab->nentries %d", | |
321 | tab->nentries); | |
322 | if (idx != tab->nentries - 1) { | |
323 | int i; | |
324 | for (i = idx; i < tab->nentries - 1; i++) | |
325 | tab->identities[i] = tab->identities[i+1]; | |
326 | } | |
327 | tab->identities[tab->nentries - 1].key = NULL; | |
328 | tab->identities[tab->nentries - 1].comment = NULL; | |
329 | tab->nentries--; | |
330 | success = 1; | |
331 | } | |
332 | key_free(key); | |
333 | } | |
334 | buffer_put_int(&e->output, 1); | |
335 | buffer_put_char(&e->output, | |
336 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
337 | } | |
338 | ||
339 | void | |
340 | process_remove_all_identities(SocketEntry *e, int version) | |
341 | { | |
342 | unsigned int i; | |
343 | Idtab *tab = idtab_lookup(version); | |
344 | ||
345 | /* Loop over all identities and clear the keys. */ | |
346 | for (i = 0; i < tab->nentries; i++) { | |
347 | key_free(tab->identities[i].key); | |
348 | xfree(tab->identities[i].comment); | |
349 | } | |
350 | ||
351 | /* Mark that there are no identities. */ | |
352 | tab->nentries = 0; | |
353 | ||
354 | /* Send success. */ | |
355 | buffer_put_int(&e->output, 1); | |
356 | buffer_put_char(&e->output, SSH_AGENT_SUCCESS); | |
357 | return; | |
358 | } | |
359 | ||
360 | void | |
361 | generate_additional_parameters(RSA *rsa) | |
362 | { | |
363 | BIGNUM *aux; | |
364 | BN_CTX *ctx; | |
365 | /* Generate additional parameters */ | |
366 | aux = BN_new(); | |
367 | ctx = BN_CTX_new(); | |
368 | ||
369 | BN_sub(aux, rsa->q, BN_value_one()); | |
370 | BN_mod(rsa->dmq1, rsa->d, aux, ctx); | |
371 | ||
372 | BN_sub(aux, rsa->p, BN_value_one()); | |
373 | BN_mod(rsa->dmp1, rsa->d, aux, ctx); | |
374 | ||
375 | BN_clear_free(aux); | |
376 | BN_CTX_free(ctx); | |
377 | } | |
378 | ||
379 | void | |
380 | process_add_identity(SocketEntry *e, int version) | |
381 | { | |
382 | Key *k = NULL; | |
383 | char *type_name; | |
384 | char *comment; | |
385 | int type, success = 0; | |
386 | Idtab *tab = idtab_lookup(version); | |
387 | ||
388 | switch (version) { | |
389 | case 1: | |
390 | k = key_new_private(KEY_RSA1); | |
391 | buffer_get_int(&e->input); /* ignored */ | |
392 | buffer_get_bignum(&e->input, k->rsa->n); | |
393 | buffer_get_bignum(&e->input, k->rsa->e); | |
394 | buffer_get_bignum(&e->input, k->rsa->d); | |
395 | buffer_get_bignum(&e->input, k->rsa->iqmp); | |
396 | ||
397 | /* SSH and SSL have p and q swapped */ | |
398 | buffer_get_bignum(&e->input, k->rsa->q); /* p */ | |
399 | buffer_get_bignum(&e->input, k->rsa->p); /* q */ | |
400 | ||
401 | /* Generate additional parameters */ | |
402 | generate_additional_parameters(k->rsa); | |
403 | break; | |
404 | case 2: | |
405 | type_name = buffer_get_string(&e->input, NULL); | |
406 | type = key_type_from_name(type_name); | |
407 | xfree(type_name); | |
408 | switch(type) { | |
409 | case KEY_DSA: | |
410 | k = key_new_private(type); | |
411 | buffer_get_bignum2(&e->input, k->dsa->p); | |
412 | buffer_get_bignum2(&e->input, k->dsa->q); | |
413 | buffer_get_bignum2(&e->input, k->dsa->g); | |
414 | buffer_get_bignum2(&e->input, k->dsa->pub_key); | |
415 | buffer_get_bignum2(&e->input, k->dsa->priv_key); | |
416 | break; | |
417 | case KEY_RSA: | |
418 | k = key_new_private(type); | |
419 | buffer_get_bignum2(&e->input, k->rsa->n); | |
420 | buffer_get_bignum2(&e->input, k->rsa->e); | |
421 | buffer_get_bignum2(&e->input, k->rsa->d); | |
422 | buffer_get_bignum2(&e->input, k->rsa->iqmp); | |
423 | buffer_get_bignum2(&e->input, k->rsa->p); | |
424 | buffer_get_bignum2(&e->input, k->rsa->q); | |
425 | ||
426 | /* Generate additional parameters */ | |
427 | generate_additional_parameters(k->rsa); | |
428 | break; | |
429 | default: | |
430 | buffer_clear(&e->input); | |
431 | goto send; | |
432 | } | |
433 | break; | |
434 | } | |
435 | comment = buffer_get_string(&e->input, NULL); | |
436 | if (k == NULL) { | |
437 | xfree(comment); | |
438 | goto send; | |
439 | } | |
440 | success = 1; | |
441 | if (lookup_private_key(k, NULL, version) == NULL) { | |
442 | if (tab->nentries == 0) | |
443 | tab->identities = xmalloc(sizeof(Identity)); | |
444 | else | |
445 | tab->identities = xrealloc(tab->identities, | |
446 | (tab->nentries + 1) * sizeof(Identity)); | |
447 | tab->identities[tab->nentries].key = k; | |
448 | tab->identities[tab->nentries].comment = comment; | |
449 | /* Increment the number of identities. */ | |
450 | tab->nentries++; | |
451 | } else { | |
452 | key_free(k); | |
453 | xfree(comment); | |
454 | } | |
455 | send: | |
456 | buffer_put_int(&e->output, 1); | |
457 | buffer_put_char(&e->output, | |
458 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
459 | } | |
460 | ||
461 | /* dispatch incoming messages */ | |
462 | ||
463 | void | |
464 | process_message(SocketEntry *e) | |
465 | { | |
466 | unsigned int msg_len; | |
467 | unsigned int type; | |
468 | unsigned char *cp; | |
469 | if (buffer_len(&e->input) < 5) | |
470 | return; /* Incomplete message. */ | |
471 | cp = (unsigned char *) buffer_ptr(&e->input); | |
472 | msg_len = GET_32BIT(cp); | |
473 | if (msg_len > 256 * 1024) { | |
474 | shutdown(e->fd, SHUT_RDWR); | |
475 | close(e->fd); | |
476 | e->type = AUTH_UNUSED; | |
477 | return; | |
478 | } | |
479 | if (buffer_len(&e->input) < msg_len + 4) | |
480 | return; | |
481 | buffer_consume(&e->input, 4); | |
482 | type = buffer_get_char(&e->input); | |
483 | ||
484 | switch (type) { | |
485 | /* ssh1 */ | |
486 | case SSH_AGENTC_RSA_CHALLENGE: | |
487 | process_authentication_challenge1(e); | |
488 | break; | |
489 | case SSH_AGENTC_REQUEST_RSA_IDENTITIES: | |
490 | process_request_identities(e, 1); | |
491 | break; | |
492 | case SSH_AGENTC_ADD_RSA_IDENTITY: | |
493 | process_add_identity(e, 1); | |
494 | break; | |
495 | case SSH_AGENTC_REMOVE_RSA_IDENTITY: | |
496 | process_remove_identity(e, 1); | |
497 | break; | |
498 | case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: | |
499 | process_remove_all_identities(e, 1); | |
500 | break; | |
501 | /* ssh2 */ | |
502 | case SSH2_AGENTC_SIGN_REQUEST: | |
503 | process_sign_request2(e); | |
504 | break; | |
505 | case SSH2_AGENTC_REQUEST_IDENTITIES: | |
506 | process_request_identities(e, 2); | |
507 | break; | |
508 | case SSH2_AGENTC_ADD_IDENTITY: | |
509 | process_add_identity(e, 2); | |
510 | break; | |
511 | case SSH2_AGENTC_REMOVE_IDENTITY: | |
512 | process_remove_identity(e, 2); | |
513 | break; | |
514 | case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: | |
515 | process_remove_all_identities(e, 2); | |
516 | break; | |
517 | default: | |
518 | /* Unknown message. Respond with failure. */ | |
519 | error("Unknown message %d", type); | |
520 | buffer_clear(&e->input); | |
521 | buffer_put_int(&e->output, 1); | |
522 | buffer_put_char(&e->output, SSH_AGENT_FAILURE); | |
523 | break; | |
524 | } | |
525 | } | |
526 | ||
527 | void | |
528 | new_socket(int type, int fd) | |
529 | { | |
530 | unsigned int i, old_alloc; | |
531 | if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) | |
532 | error("fcntl O_NONBLOCK: %s", strerror(errno)); | |
533 | ||
534 | if (fd > max_fd) | |
535 | max_fd = fd; | |
536 | ||
537 | for (i = 0; i < sockets_alloc; i++) | |
538 | if (sockets[i].type == AUTH_UNUSED) { | |
539 | sockets[i].fd = fd; | |
540 | sockets[i].type = type; | |
541 | buffer_init(&sockets[i].input); | |
542 | buffer_init(&sockets[i].output); | |
543 | return; | |
544 | } | |
545 | old_alloc = sockets_alloc; | |
546 | sockets_alloc += 10; | |
547 | if (sockets) | |
548 | sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); | |
549 | else | |
550 | sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); | |
551 | for (i = old_alloc; i < sockets_alloc; i++) | |
552 | sockets[i].type = AUTH_UNUSED; | |
553 | sockets[old_alloc].type = type; | |
554 | sockets[old_alloc].fd = fd; | |
555 | buffer_init(&sockets[old_alloc].input); | |
556 | buffer_init(&sockets[old_alloc].output); | |
557 | } | |
558 | ||
559 | void | |
560 | prepare_select(fd_set *readset, fd_set *writeset) | |
561 | { | |
562 | unsigned int i; | |
563 | for (i = 0; i < sockets_alloc; i++) | |
564 | switch (sockets[i].type) { | |
565 | case AUTH_SOCKET: | |
566 | case AUTH_CONNECTION: | |
567 | FD_SET(sockets[i].fd, readset); | |
568 | if (buffer_len(&sockets[i].output) > 0) | |
569 | FD_SET(sockets[i].fd, writeset); | |
570 | break; | |
571 | case AUTH_UNUSED: | |
572 | break; | |
573 | default: | |
574 | fatal("Unknown socket type %d", sockets[i].type); | |
575 | break; | |
576 | } | |
577 | } | |
578 | ||
579 | void | |
580 | after_select(fd_set *readset, fd_set *writeset) | |
581 | { | |
582 | unsigned int i; | |
583 | int len, sock; | |
584 | socklen_t slen; | |
585 | char buf[1024]; | |
586 | struct sockaddr_un sunaddr; | |
587 | ||
588 | for (i = 0; i < sockets_alloc; i++) | |
589 | switch (sockets[i].type) { | |
590 | case AUTH_UNUSED: | |
591 | break; | |
592 | case AUTH_SOCKET: | |
593 | if (FD_ISSET(sockets[i].fd, readset)) { | |
594 | slen = sizeof(sunaddr); | |
595 | sock = accept(sockets[i].fd, (struct sockaddr *) & sunaddr, &slen); | |
596 | if (sock < 0) { | |
597 | perror("accept from AUTH_SOCKET"); | |
598 | break; | |
599 | } | |
600 | new_socket(AUTH_CONNECTION, sock); | |
601 | } | |
602 | break; | |
603 | case AUTH_CONNECTION: | |
604 | if (buffer_len(&sockets[i].output) > 0 && | |
605 | FD_ISSET(sockets[i].fd, writeset)) { | |
606 | len = write(sockets[i].fd, buffer_ptr(&sockets[i].output), | |
607 | buffer_len(&sockets[i].output)); | |
608 | if (len <= 0) { | |
609 | shutdown(sockets[i].fd, SHUT_RDWR); | |
610 | close(sockets[i].fd); | |
611 | sockets[i].type = AUTH_UNUSED; | |
612 | buffer_free(&sockets[i].input); | |
613 | buffer_free(&sockets[i].output); | |
614 | break; | |
615 | } | |
616 | buffer_consume(&sockets[i].output, len); | |
617 | } | |
618 | if (FD_ISSET(sockets[i].fd, readset)) { | |
619 | len = read(sockets[i].fd, buf, sizeof(buf)); | |
620 | if (len <= 0) { | |
621 | shutdown(sockets[i].fd, SHUT_RDWR); | |
622 | close(sockets[i].fd); | |
623 | sockets[i].type = AUTH_UNUSED; | |
624 | buffer_free(&sockets[i].input); | |
625 | buffer_free(&sockets[i].output); | |
626 | break; | |
627 | } | |
628 | buffer_append(&sockets[i].input, buf, len); | |
629 | process_message(&sockets[i]); | |
630 | } | |
631 | break; | |
632 | default: | |
633 | fatal("Unknown type %d", sockets[i].type); | |
634 | } | |
635 | } | |
636 | ||
637 | void | |
638 | check_parent_exists(int sig) | |
639 | { | |
640 | if (parent_pid != -1 && kill(parent_pid, 0) < 0) { | |
641 | /* printf("Parent has died - Authentication agent exiting.\n"); */ | |
642 | exit(1); | |
643 | } | |
644 | signal(SIGALRM, check_parent_exists); | |
645 | alarm(10); | |
646 | } | |
647 | ||
648 | void | |
649 | cleanup_socket(void) | |
650 | { | |
651 | unlink(socket_name); | |
652 | rmdir(socket_dir); | |
653 | } | |
654 | ||
655 | void | |
656 | cleanup_exit(int i) | |
657 | { | |
658 | cleanup_socket(); | |
659 | exit(i); | |
660 | } | |
661 | ||
662 | void | |
663 | usage() | |
664 | { | |
665 | fprintf(stderr, "ssh-agent version %s\n", SSH_VERSION); | |
666 | fprintf(stderr, "Usage: %s [-c | -s] [-k] [command {args...]]\n", | |
667 | __progname); | |
668 | exit(1); | |
669 | } | |
670 | ||
671 | int | |
672 | main(int ac, char **av) | |
673 | { | |
674 | fd_set readset, writeset; | |
675 | int sock, c_flag = 0, k_flag = 0, s_flag = 0, ch; | |
676 | struct sockaddr_un sunaddr; | |
677 | pid_t pid; | |
678 | char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; | |
679 | extern int optind; | |
680 | ||
681 | __progname = get_progname(av[0]); | |
682 | init_rng(); | |
683 | ||
684 | #ifdef __GNU_LIBRARY__ | |
685 | while ((ch = getopt(ac, av, "+cks")) != -1) { | |
686 | #else /* __GNU_LIBRARY__ */ | |
687 | while ((ch = getopt(ac, av, "cks")) != -1) { | |
688 | #endif /* __GNU_LIBRARY__ */ | |
689 | switch (ch) { | |
690 | case 'c': | |
691 | if (s_flag) | |
692 | usage(); | |
693 | c_flag++; | |
694 | break; | |
695 | case 'k': | |
696 | k_flag++; | |
697 | break; | |
698 | case 's': | |
699 | if (c_flag) | |
700 | usage(); | |
701 | s_flag++; | |
702 | break; | |
703 | default: | |
704 | usage(); | |
705 | } | |
706 | } | |
707 | ac -= optind; | |
708 | av += optind; | |
709 | ||
710 | if (ac > 0 && (c_flag || k_flag || s_flag)) | |
711 | usage(); | |
712 | ||
713 | if (ac == 0 && !c_flag && !k_flag && !s_flag) { | |
714 | shell = getenv("SHELL"); | |
715 | if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) | |
716 | c_flag = 1; | |
717 | } | |
718 | if (k_flag) { | |
719 | pidstr = getenv(SSH_AGENTPID_ENV_NAME); | |
720 | if (pidstr == NULL) { | |
721 | fprintf(stderr, "%s not set, cannot kill agent\n", | |
722 | SSH_AGENTPID_ENV_NAME); | |
723 | exit(1); | |
724 | } | |
725 | pid = atoi(pidstr); | |
726 | if (pid < 1) { /* XXX PID_MAX check too */ | |
727 | /* Yes, PID_MAX check please */ | |
728 | fprintf(stderr, "%s=\"%s\", which is not a good PID\n", | |
729 | SSH_AGENTPID_ENV_NAME, pidstr); | |
730 | exit(1); | |
731 | } | |
732 | if (kill(pid, SIGTERM) == -1) { | |
733 | perror("kill"); | |
734 | exit(1); | |
735 | } | |
736 | format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; | |
737 | printf(format, SSH_AUTHSOCKET_ENV_NAME); | |
738 | printf(format, SSH_AGENTPID_ENV_NAME); | |
739 | printf("echo Agent pid %d killed;\n", pid); | |
740 | exit(0); | |
741 | } | |
742 | parent_pid = getpid(); | |
743 | ||
744 | /* Create private directory for agent socket */ | |
745 | strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); | |
746 | if (mkdtemp(socket_dir) == NULL) { | |
747 | perror("mkdtemp: private socket dir"); | |
748 | exit(1); | |
749 | } | |
750 | snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir, | |
751 | parent_pid); | |
752 | ||
753 | /* | |
754 | * Create socket early so it will exist before command gets run from | |
755 | * the parent. | |
756 | */ | |
757 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
758 | if (sock < 0) { | |
759 | perror("socket"); | |
760 | cleanup_exit(1); | |
761 | } | |
762 | memset(&sunaddr, 0, sizeof(sunaddr)); | |
763 | sunaddr.sun_family = AF_UNIX; | |
764 | strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); | |
765 | if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { | |
766 | perror("bind"); | |
767 | cleanup_exit(1); | |
768 | } | |
769 | if (listen(sock, 5) < 0) { | |
770 | perror("listen"); | |
771 | cleanup_exit(1); | |
772 | } | |
773 | /* | |
774 | * Fork, and have the parent execute the command, if any, or present | |
775 | * the socket data. The child continues as the authentication agent. | |
776 | */ | |
777 | pid = fork(); | |
778 | if (pid == -1) { | |
779 | perror("fork"); | |
780 | exit(1); | |
781 | } | |
782 | if (pid != 0) { /* Parent - execute the given command. */ | |
783 | close(sock); | |
784 | snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid); | |
785 | if (ac == 0) { | |
786 | format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; | |
787 | printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, | |
788 | SSH_AUTHSOCKET_ENV_NAME); | |
789 | printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, | |
790 | SSH_AGENTPID_ENV_NAME); | |
791 | printf("echo Agent pid %d;\n", pid); | |
792 | exit(0); | |
793 | } | |
794 | if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || | |
795 | setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { | |
796 | perror("setenv"); | |
797 | exit(1); | |
798 | } | |
799 | execvp(av[0], av); | |
800 | perror(av[0]); | |
801 | exit(1); | |
802 | } | |
803 | close(0); | |
804 | close(1); | |
805 | close(2); | |
806 | ||
807 | if (setsid() == -1) { | |
808 | perror("setsid"); | |
809 | cleanup_exit(1); | |
810 | } | |
811 | if (atexit(cleanup_socket) < 0) { | |
812 | perror("atexit"); | |
813 | cleanup_exit(1); | |
814 | } | |
815 | new_socket(AUTH_SOCKET, sock); | |
816 | if (ac > 0) { | |
817 | signal(SIGALRM, check_parent_exists); | |
818 | alarm(10); | |
819 | } | |
820 | idtab_init(); | |
821 | signal(SIGINT, SIG_IGN); | |
822 | signal(SIGPIPE, SIG_IGN); | |
823 | signal(SIGHUP, cleanup_exit); | |
824 | signal(SIGTERM, cleanup_exit); | |
825 | while (1) { | |
826 | FD_ZERO(&readset); | |
827 | FD_ZERO(&writeset); | |
828 | prepare_select(&readset, &writeset); | |
829 | if (select(max_fd + 1, &readset, &writeset, NULL, NULL) < 0) { | |
830 | if (errno == EINTR) | |
831 | continue; | |
832 | exit(1); | |
833 | } | |
834 | after_select(&readset, &writeset); | |
835 | } | |
836 | /* NOTREACHED */ | |
837 | } |