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1 | /* $OpenBSD: ssh-agent.c,v 1.77 2001/12/29 21:56:01 stevesk 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 | * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. | |
16 | * | |
17 | * Redistribution and use in source and binary forms, with or without | |
18 | * modification, are permitted provided that the following conditions | |
19 | * are met: | |
20 | * 1. Redistributions of source code must retain the above copyright | |
21 | * notice, this list of conditions and the following disclaimer. | |
22 | * 2. Redistributions in binary form must reproduce the above copyright | |
23 | * notice, this list of conditions and the following disclaimer in the | |
24 | * documentation and/or other materials provided with the distribution. | |
25 | * | |
26 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
27 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
28 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
29 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
30 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
31 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
32 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
33 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
34 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
35 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
36 | */ | |
37 | ||
38 | #include "includes.h" | |
39 | RCSID("$OpenBSD: ssh-agent.c,v 1.77 2001/12/29 21:56:01 stevesk Exp $"); | |
40 | ||
41 | #include <openssl/evp.h> | |
42 | #include <openssl/md5.h> | |
43 | ||
44 | #include "ssh.h" | |
45 | #include "rsa.h" | |
46 | #include "buffer.h" | |
47 | #include "bufaux.h" | |
48 | #include "xmalloc.h" | |
49 | #include "packet.h" | |
50 | #include "getput.h" | |
51 | #include "mpaux.h" | |
52 | #include "key.h" | |
53 | #include "authfd.h" | |
54 | #include "cipher.h" | |
55 | #include "kex.h" | |
56 | #include "compat.h" | |
57 | #include "log.h" | |
58 | ||
59 | #ifdef SMARTCARD | |
60 | #include <openssl/engine.h> | |
61 | #include "scard.h" | |
62 | #endif | |
63 | ||
64 | typedef enum { | |
65 | AUTH_UNUSED, | |
66 | AUTH_SOCKET, | |
67 | AUTH_CONNECTION | |
68 | } sock_type; | |
69 | ||
70 | typedef struct { | |
71 | int fd; | |
72 | sock_type type; | |
73 | Buffer input; | |
74 | Buffer output; | |
75 | } SocketEntry; | |
76 | ||
77 | u_int sockets_alloc = 0; | |
78 | SocketEntry *sockets = NULL; | |
79 | ||
80 | typedef struct { | |
81 | Key *key; | |
82 | char *comment; | |
83 | } Identity; | |
84 | ||
85 | typedef struct { | |
86 | int nentries; | |
87 | Identity *identities; | |
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 | idtable[i].identities = NULL; | |
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 Key * | |
129 | lookup_private_key(Key *key, int *idx, int version) | |
130 | { | |
131 | int i; | |
132 | Idtab *tab = idtab_lookup(version); | |
133 | for (i = 0; i < tab->nentries; i++) { | |
134 | if (key_equal(key, tab->identities[i].key)) { | |
135 | if (idx != NULL) | |
136 | *idx = i; | |
137 | return tab->identities[i].key; | |
138 | } | |
139 | } | |
140 | return NULL; | |
141 | } | |
142 | ||
143 | /* send list of supported public keys to 'client' */ | |
144 | static void | |
145 | process_request_identities(SocketEntry *e, int version) | |
146 | { | |
147 | Idtab *tab = idtab_lookup(version); | |
148 | Buffer msg; | |
149 | int i; | |
150 | ||
151 | buffer_init(&msg); | |
152 | buffer_put_char(&msg, (version == 1) ? | |
153 | SSH_AGENT_RSA_IDENTITIES_ANSWER : SSH2_AGENT_IDENTITIES_ANSWER); | |
154 | buffer_put_int(&msg, tab->nentries); | |
155 | for (i = 0; i < tab->nentries; i++) { | |
156 | Identity *id = &tab->identities[i]; | |
157 | if (id->key->type == KEY_RSA1) { | |
158 | buffer_put_int(&msg, BN_num_bits(id->key->rsa->n)); | |
159 | buffer_put_bignum(&msg, id->key->rsa->e); | |
160 | buffer_put_bignum(&msg, id->key->rsa->n); | |
161 | } else { | |
162 | u_char *blob; | |
163 | u_int blen; | |
164 | key_to_blob(id->key, &blob, &blen); | |
165 | buffer_put_string(&msg, blob, blen); | |
166 | xfree(blob); | |
167 | } | |
168 | buffer_put_cstring(&msg, id->comment); | |
169 | } | |
170 | buffer_put_int(&e->output, buffer_len(&msg)); | |
171 | buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); | |
172 | buffer_free(&msg); | |
173 | } | |
174 | ||
175 | /* ssh1 only */ | |
176 | static void | |
177 | process_authentication_challenge1(SocketEntry *e) | |
178 | { | |
179 | Key *key, *private; | |
180 | BIGNUM *challenge; | |
181 | int i, len; | |
182 | Buffer msg; | |
183 | MD5_CTX md; | |
184 | u_char buf[32], mdbuf[16], session_id[16]; | |
185 | u_int response_type; | |
186 | ||
187 | buffer_init(&msg); | |
188 | key = key_new(KEY_RSA1); | |
189 | if ((challenge = BN_new()) == NULL) | |
190 | fatal("process_authentication_challenge1: BN_new failed"); | |
191 | ||
192 | buffer_get_int(&e->input); /* ignored */ | |
193 | buffer_get_bignum(&e->input, key->rsa->e); | |
194 | buffer_get_bignum(&e->input, key->rsa->n); | |
195 | buffer_get_bignum(&e->input, challenge); | |
196 | ||
197 | /* Only protocol 1.1 is supported */ | |
198 | if (buffer_len(&e->input) == 0) | |
199 | goto failure; | |
200 | buffer_get(&e->input, (char *) session_id, 16); | |
201 | response_type = buffer_get_int(&e->input); | |
202 | if (response_type != 1) | |
203 | goto failure; | |
204 | ||
205 | private = lookup_private_key(key, NULL, 1); | |
206 | if (private != NULL) { | |
207 | /* Decrypt the challenge using the private key. */ | |
208 | if (rsa_private_decrypt(challenge, challenge, private->rsa) <= 0) | |
209 | goto failure; | |
210 | ||
211 | /* The response is MD5 of decrypted challenge plus session id. */ | |
212 | len = BN_num_bytes(challenge); | |
213 | if (len <= 0 || len > 32) { | |
214 | log("process_authentication_challenge: bad challenge length %d", len); | |
215 | goto failure; | |
216 | } | |
217 | memset(buf, 0, 32); | |
218 | BN_bn2bin(challenge, buf + 32 - len); | |
219 | MD5_Init(&md); | |
220 | MD5_Update(&md, buf, 32); | |
221 | MD5_Update(&md, session_id, 16); | |
222 | MD5_Final(mdbuf, &md); | |
223 | ||
224 | /* Send the response. */ | |
225 | buffer_put_char(&msg, SSH_AGENT_RSA_RESPONSE); | |
226 | for (i = 0; i < 16; i++) | |
227 | buffer_put_char(&msg, mdbuf[i]); | |
228 | goto send; | |
229 | } | |
230 | ||
231 | failure: | |
232 | /* Unknown identity or protocol error. Send failure. */ | |
233 | buffer_put_char(&msg, SSH_AGENT_FAILURE); | |
234 | send: | |
235 | buffer_put_int(&e->output, buffer_len(&msg)); | |
236 | buffer_append(&e->output, buffer_ptr(&msg), buffer_len(&msg)); | |
237 | key_free(key); | |
238 | BN_clear_free(challenge); | |
239 | buffer_free(&msg); | |
240 | } | |
241 | ||
242 | /* ssh2 only */ | |
243 | static void | |
244 | process_sign_request2(SocketEntry *e) | |
245 | { | |
246 | extern int datafellows; | |
247 | Key *key, *private; | |
248 | u_char *blob, *data, *signature = NULL; | |
249 | u_int blen, dlen, slen = 0; | |
250 | int flags; | |
251 | Buffer msg; | |
252 | int ok = -1; | |
253 | ||
254 | datafellows = 0; | |
255 | ||
256 | blob = buffer_get_string(&e->input, &blen); | |
257 | data = buffer_get_string(&e->input, &dlen); | |
258 | ||
259 | flags = buffer_get_int(&e->input); | |
260 | if (flags & SSH_AGENT_OLD_SIGNATURE) | |
261 | datafellows = SSH_BUG_SIGBLOB; | |
262 | ||
263 | key = key_from_blob(blob, blen); | |
264 | if (key != NULL) { | |
265 | private = lookup_private_key(key, NULL, 2); | |
266 | if (private != NULL) | |
267 | ok = key_sign(private, &signature, &slen, data, dlen); | |
268 | } | |
269 | key_free(key); | |
270 | buffer_init(&msg); | |
271 | if (ok == 0) { | |
272 | buffer_put_char(&msg, SSH2_AGENT_SIGN_RESPONSE); | |
273 | buffer_put_string(&msg, signature, slen); | |
274 | } else { | |
275 | buffer_put_char(&msg, SSH_AGENT_FAILURE); | |
276 | } | |
277 | buffer_put_int(&e->output, buffer_len(&msg)); | |
278 | buffer_append(&e->output, buffer_ptr(&msg), | |
279 | buffer_len(&msg)); | |
280 | buffer_free(&msg); | |
281 | xfree(data); | |
282 | xfree(blob); | |
283 | if (signature != NULL) | |
284 | xfree(signature); | |
285 | } | |
286 | ||
287 | /* shared */ | |
288 | static void | |
289 | process_remove_identity(SocketEntry *e, int version) | |
290 | { | |
291 | Key *key = NULL, *private; | |
292 | u_char *blob; | |
293 | u_int blen; | |
294 | u_int bits; | |
295 | int success = 0; | |
296 | ||
297 | switch (version) { | |
298 | case 1: | |
299 | key = key_new(KEY_RSA1); | |
300 | bits = buffer_get_int(&e->input); | |
301 | buffer_get_bignum(&e->input, key->rsa->e); | |
302 | buffer_get_bignum(&e->input, key->rsa->n); | |
303 | ||
304 | if (bits != key_size(key)) | |
305 | log("Warning: identity keysize mismatch: actual %d, announced %d", | |
306 | key_size(key), bits); | |
307 | break; | |
308 | case 2: | |
309 | blob = buffer_get_string(&e->input, &blen); | |
310 | key = key_from_blob(blob, blen); | |
311 | xfree(blob); | |
312 | break; | |
313 | } | |
314 | if (key != NULL) { | |
315 | int idx; | |
316 | private = lookup_private_key(key, &idx, version); | |
317 | if (private != NULL) { | |
318 | /* | |
319 | * We have this key. Free the old key. Since we | |
320 | * don\'t want to leave empty slots in the middle of | |
321 | * the array, we actually free the key there and move | |
322 | * all the entries between the empty slot and the end | |
323 | * of the array. | |
324 | */ | |
325 | Idtab *tab = idtab_lookup(version); | |
326 | key_free(tab->identities[idx].key); | |
327 | xfree(tab->identities[idx].comment); | |
328 | if (tab->nentries < 1) | |
329 | fatal("process_remove_identity: " | |
330 | "internal error: tab->nentries %d", | |
331 | tab->nentries); | |
332 | if (idx != tab->nentries - 1) { | |
333 | int i; | |
334 | for (i = idx; i < tab->nentries - 1; i++) | |
335 | tab->identities[i] = tab->identities[i+1]; | |
336 | } | |
337 | tab->identities[tab->nentries - 1].key = NULL; | |
338 | tab->identities[tab->nentries - 1].comment = NULL; | |
339 | tab->nentries--; | |
340 | success = 1; | |
341 | } | |
342 | key_free(key); | |
343 | } | |
344 | buffer_put_int(&e->output, 1); | |
345 | buffer_put_char(&e->output, | |
346 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
347 | } | |
348 | ||
349 | static void | |
350 | process_remove_all_identities(SocketEntry *e, int version) | |
351 | { | |
352 | u_int i; | |
353 | Idtab *tab = idtab_lookup(version); | |
354 | ||
355 | /* Loop over all identities and clear the keys. */ | |
356 | for (i = 0; i < tab->nentries; i++) { | |
357 | key_free(tab->identities[i].key); | |
358 | xfree(tab->identities[i].comment); | |
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_private_key(k, NULL, version) == NULL) { | |
433 | if (tab->nentries == 0) | |
434 | tab->identities = xmalloc(sizeof(Identity)); | |
435 | else | |
436 | tab->identities = xrealloc(tab->identities, | |
437 | (tab->nentries + 1) * sizeof(Identity)); | |
438 | tab->identities[tab->nentries].key = k; | |
439 | tab->identities[tab->nentries].comment = comment; | |
440 | /* Increment the number of identities. */ | |
441 | tab->nentries++; | |
442 | } else { | |
443 | key_free(k); | |
444 | xfree(comment); | |
445 | } | |
446 | send: | |
447 | buffer_put_int(&e->output, 1); | |
448 | buffer_put_char(&e->output, | |
449 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
450 | } | |
451 | ||
452 | ||
453 | #ifdef SMARTCARD | |
454 | static void | |
455 | process_add_smartcard_key (SocketEntry *e) | |
456 | { | |
457 | Idtab *tab; | |
458 | Key *n = NULL, *k = NULL; | |
459 | char *sc_reader_id = NULL; | |
460 | int success = 0; | |
461 | ||
462 | sc_reader_id = buffer_get_string(&e->input, NULL); | |
463 | k = sc_get_key(sc_reader_id); | |
464 | xfree(sc_reader_id); | |
465 | ||
466 | if (k == NULL) { | |
467 | error("sc_get_pubkey failed"); | |
468 | goto send; | |
469 | } | |
470 | success = 1; | |
471 | ||
472 | tab = idtab_lookup(1); | |
473 | k->type = KEY_RSA1; | |
474 | if (lookup_private_key(k, NULL, 1) == NULL) { | |
475 | if (tab->nentries == 0) | |
476 | tab->identities = xmalloc(sizeof(Identity)); | |
477 | else | |
478 | tab->identities = xrealloc(tab->identities, | |
479 | (tab->nentries + 1) * sizeof(Identity)); | |
480 | n = key_new(KEY_RSA1); | |
481 | BN_copy(n->rsa->n, k->rsa->n); | |
482 | BN_copy(n->rsa->e, k->rsa->e); | |
483 | RSA_set_method(n->rsa, sc_get_engine()); | |
484 | tab->identities[tab->nentries].key = n; | |
485 | tab->identities[tab->nentries].comment = | |
486 | xstrdup("rsa1 smartcard"); | |
487 | tab->nentries++; | |
488 | } | |
489 | k->type = KEY_RSA; | |
490 | tab = idtab_lookup(2); | |
491 | if (lookup_private_key(k, NULL, 2) == NULL) { | |
492 | if (tab->nentries == 0) | |
493 | tab->identities = xmalloc(sizeof(Identity)); | |
494 | else | |
495 | tab->identities = xrealloc(tab->identities, | |
496 | (tab->nentries + 1) * sizeof(Identity)); | |
497 | n = key_new(KEY_RSA); | |
498 | BN_copy(n->rsa->n, k->rsa->n); | |
499 | BN_copy(n->rsa->e, k->rsa->e); | |
500 | RSA_set_method(n->rsa, sc_get_engine()); | |
501 | tab->identities[tab->nentries].key = n; | |
502 | tab->identities[tab->nentries].comment = | |
503 | xstrdup("rsa smartcard"); | |
504 | tab->nentries++; | |
505 | } | |
506 | key_free(k); | |
507 | send: | |
508 | buffer_put_int(&e->output, 1); | |
509 | buffer_put_char(&e->output, | |
510 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
511 | } | |
512 | ||
513 | static void | |
514 | process_remove_smartcard_key(SocketEntry *e) | |
515 | { | |
516 | Key *k = NULL, *private; | |
517 | int idx; | |
518 | int success = 0; | |
519 | char *sc_reader_id = NULL; | |
520 | ||
521 | sc_reader_id = buffer_get_string(&e->input, NULL); | |
522 | k = sc_get_key(sc_reader_id); | |
523 | xfree(sc_reader_id); | |
524 | ||
525 | if (k == NULL) { | |
526 | error("sc_get_pubkey failed"); | |
527 | } else { | |
528 | k->type = KEY_RSA1; | |
529 | private = lookup_private_key(k, &idx, 1); | |
530 | if (private != NULL) { | |
531 | Idtab *tab = idtab_lookup(1); | |
532 | key_free(tab->identities[idx].key); | |
533 | xfree(tab->identities[idx].comment); | |
534 | if (idx != tab->nentries) | |
535 | tab->identities[idx] = tab->identities[tab->nentries]; | |
536 | tab->nentries--; | |
537 | success = 1; | |
538 | } | |
539 | k->type = KEY_RSA; | |
540 | private = lookup_private_key(k, &idx, 2); | |
541 | if (private != NULL) { | |
542 | Idtab *tab = idtab_lookup(2); | |
543 | key_free(tab->identities[idx].key); | |
544 | xfree(tab->identities[idx].comment); | |
545 | if (idx != tab->nentries) | |
546 | tab->identities[idx] = tab->identities[tab->nentries]; | |
547 | tab->nentries--; | |
548 | success = 1; | |
549 | } | |
550 | key_free(k); | |
551 | } | |
552 | ||
553 | buffer_put_int(&e->output, 1); | |
554 | buffer_put_char(&e->output, | |
555 | success ? SSH_AGENT_SUCCESS : SSH_AGENT_FAILURE); | |
556 | } | |
557 | #endif /* SMARTCARD */ | |
558 | ||
559 | /* dispatch incoming messages */ | |
560 | ||
561 | static void | |
562 | process_message(SocketEntry *e) | |
563 | { | |
564 | u_int msg_len; | |
565 | u_int type; | |
566 | u_char *cp; | |
567 | if (buffer_len(&e->input) < 5) | |
568 | return; /* Incomplete message. */ | |
569 | cp = buffer_ptr(&e->input); | |
570 | msg_len = GET_32BIT(cp); | |
571 | if (msg_len > 256 * 1024) { | |
572 | shutdown(e->fd, SHUT_RDWR); | |
573 | close(e->fd); | |
574 | e->type = AUTH_UNUSED; | |
575 | return; | |
576 | } | |
577 | if (buffer_len(&e->input) < msg_len + 4) | |
578 | return; | |
579 | buffer_consume(&e->input, 4); | |
580 | type = buffer_get_char(&e->input); | |
581 | ||
582 | debug("type %d", type); | |
583 | switch (type) { | |
584 | /* ssh1 */ | |
585 | case SSH_AGENTC_RSA_CHALLENGE: | |
586 | process_authentication_challenge1(e); | |
587 | break; | |
588 | case SSH_AGENTC_REQUEST_RSA_IDENTITIES: | |
589 | process_request_identities(e, 1); | |
590 | break; | |
591 | case SSH_AGENTC_ADD_RSA_IDENTITY: | |
592 | process_add_identity(e, 1); | |
593 | break; | |
594 | case SSH_AGENTC_REMOVE_RSA_IDENTITY: | |
595 | process_remove_identity(e, 1); | |
596 | break; | |
597 | case SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES: | |
598 | process_remove_all_identities(e, 1); | |
599 | break; | |
600 | /* ssh2 */ | |
601 | case SSH2_AGENTC_SIGN_REQUEST: | |
602 | process_sign_request2(e); | |
603 | break; | |
604 | case SSH2_AGENTC_REQUEST_IDENTITIES: | |
605 | process_request_identities(e, 2); | |
606 | break; | |
607 | case SSH2_AGENTC_ADD_IDENTITY: | |
608 | process_add_identity(e, 2); | |
609 | break; | |
610 | case SSH2_AGENTC_REMOVE_IDENTITY: | |
611 | process_remove_identity(e, 2); | |
612 | break; | |
613 | case SSH2_AGENTC_REMOVE_ALL_IDENTITIES: | |
614 | process_remove_all_identities(e, 2); | |
615 | break; | |
616 | #ifdef SMARTCARD | |
617 | case SSH_AGENTC_ADD_SMARTCARD_KEY: | |
618 | process_add_smartcard_key(e); | |
619 | break; | |
620 | case SSH_AGENTC_REMOVE_SMARTCARD_KEY: | |
621 | process_remove_smartcard_key(e); | |
622 | break; | |
623 | #endif /* SMARTCARD */ | |
624 | default: | |
625 | /* Unknown message. Respond with failure. */ | |
626 | error("Unknown message %d", type); | |
627 | buffer_clear(&e->input); | |
628 | buffer_put_int(&e->output, 1); | |
629 | buffer_put_char(&e->output, SSH_AGENT_FAILURE); | |
630 | break; | |
631 | } | |
632 | } | |
633 | ||
634 | static void | |
635 | new_socket(sock_type type, int fd) | |
636 | { | |
637 | u_int i, old_alloc; | |
638 | if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0) | |
639 | error("fcntl O_NONBLOCK: %s", strerror(errno)); | |
640 | ||
641 | if (fd > max_fd) | |
642 | max_fd = fd; | |
643 | ||
644 | for (i = 0; i < sockets_alloc; i++) | |
645 | if (sockets[i].type == AUTH_UNUSED) { | |
646 | sockets[i].fd = fd; | |
647 | sockets[i].type = type; | |
648 | buffer_init(&sockets[i].input); | |
649 | buffer_init(&sockets[i].output); | |
650 | return; | |
651 | } | |
652 | old_alloc = sockets_alloc; | |
653 | sockets_alloc += 10; | |
654 | if (sockets) | |
655 | sockets = xrealloc(sockets, sockets_alloc * sizeof(sockets[0])); | |
656 | else | |
657 | sockets = xmalloc(sockets_alloc * sizeof(sockets[0])); | |
658 | for (i = old_alloc; i < sockets_alloc; i++) | |
659 | sockets[i].type = AUTH_UNUSED; | |
660 | sockets[old_alloc].type = type; | |
661 | sockets[old_alloc].fd = fd; | |
662 | buffer_init(&sockets[old_alloc].input); | |
663 | buffer_init(&sockets[old_alloc].output); | |
664 | } | |
665 | ||
666 | static int | |
667 | prepare_select(fd_set **fdrp, fd_set **fdwp, int *fdl, int *nallocp) | |
668 | { | |
669 | u_int i, sz; | |
670 | int n = 0; | |
671 | ||
672 | for (i = 0; i < sockets_alloc; i++) { | |
673 | switch (sockets[i].type) { | |
674 | case AUTH_SOCKET: | |
675 | case AUTH_CONNECTION: | |
676 | n = MAX(n, sockets[i].fd); | |
677 | break; | |
678 | case AUTH_UNUSED: | |
679 | break; | |
680 | default: | |
681 | fatal("Unknown socket type %d", sockets[i].type); | |
682 | break; | |
683 | } | |
684 | } | |
685 | ||
686 | sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); | |
687 | if (*fdrp == NULL || sz > *nallocp) { | |
688 | if (*fdrp) | |
689 | xfree(*fdrp); | |
690 | if (*fdwp) | |
691 | xfree(*fdwp); | |
692 | *fdrp = xmalloc(sz); | |
693 | *fdwp = xmalloc(sz); | |
694 | *nallocp = sz; | |
695 | } | |
696 | if (n < *fdl) | |
697 | debug("XXX shrink: %d < %d", n, *fdl); | |
698 | *fdl = n; | |
699 | memset(*fdrp, 0, sz); | |
700 | memset(*fdwp, 0, sz); | |
701 | ||
702 | for (i = 0; i < sockets_alloc; i++) { | |
703 | switch (sockets[i].type) { | |
704 | case AUTH_SOCKET: | |
705 | case AUTH_CONNECTION: | |
706 | FD_SET(sockets[i].fd, *fdrp); | |
707 | if (buffer_len(&sockets[i].output) > 0) | |
708 | FD_SET(sockets[i].fd, *fdwp); | |
709 | break; | |
710 | default: | |
711 | break; | |
712 | } | |
713 | } | |
714 | return (1); | |
715 | } | |
716 | ||
717 | static void | |
718 | after_select(fd_set *readset, fd_set *writeset) | |
719 | { | |
720 | u_int i; | |
721 | int len, sock; | |
722 | socklen_t slen; | |
723 | char buf[1024]; | |
724 | struct sockaddr_un sunaddr; | |
725 | ||
726 | for (i = 0; i < sockets_alloc; i++) | |
727 | switch (sockets[i].type) { | |
728 | case AUTH_UNUSED: | |
729 | break; | |
730 | case AUTH_SOCKET: | |
731 | if (FD_ISSET(sockets[i].fd, readset)) { | |
732 | slen = sizeof(sunaddr); | |
733 | sock = accept(sockets[i].fd, | |
734 | (struct sockaddr *) &sunaddr, &slen); | |
735 | if (sock < 0) { | |
736 | perror("accept from AUTH_SOCKET"); | |
737 | break; | |
738 | } | |
739 | new_socket(AUTH_CONNECTION, sock); | |
740 | } | |
741 | break; | |
742 | case AUTH_CONNECTION: | |
743 | if (buffer_len(&sockets[i].output) > 0 && | |
744 | FD_ISSET(sockets[i].fd, writeset)) { | |
745 | do { | |
746 | len = write(sockets[i].fd, | |
747 | buffer_ptr(&sockets[i].output), | |
748 | buffer_len(&sockets[i].output)); | |
749 | if (len == -1 && (errno == EAGAIN || | |
750 | errno == EINTR)) | |
751 | continue; | |
752 | break; | |
753 | } while (1); | |
754 | if (len <= 0) { | |
755 | shutdown(sockets[i].fd, SHUT_RDWR); | |
756 | close(sockets[i].fd); | |
757 | sockets[i].type = AUTH_UNUSED; | |
758 | buffer_free(&sockets[i].input); | |
759 | buffer_free(&sockets[i].output); | |
760 | break; | |
761 | } | |
762 | buffer_consume(&sockets[i].output, len); | |
763 | } | |
764 | if (FD_ISSET(sockets[i].fd, readset)) { | |
765 | do { | |
766 | len = read(sockets[i].fd, buf, sizeof(buf)); | |
767 | if (len == -1 && (errno == EAGAIN || | |
768 | errno == EINTR)) | |
769 | continue; | |
770 | break; | |
771 | } while (1); | |
772 | if (len <= 0) { | |
773 | shutdown(sockets[i].fd, SHUT_RDWR); | |
774 | close(sockets[i].fd); | |
775 | sockets[i].type = AUTH_UNUSED; | |
776 | buffer_free(&sockets[i].input); | |
777 | buffer_free(&sockets[i].output); | |
778 | break; | |
779 | } | |
780 | buffer_append(&sockets[i].input, buf, len); | |
781 | process_message(&sockets[i]); | |
782 | } | |
783 | break; | |
784 | default: | |
785 | fatal("Unknown type %d", sockets[i].type); | |
786 | } | |
787 | } | |
788 | ||
789 | static void | |
790 | cleanup_socket(void) | |
791 | { | |
792 | if (socket_name[0]) | |
793 | unlink(socket_name); | |
794 | if (socket_dir[0]) | |
795 | rmdir(socket_dir); | |
796 | } | |
797 | ||
798 | static void | |
799 | cleanup_exit(int i) | |
800 | { | |
801 | cleanup_socket(); | |
802 | exit(i); | |
803 | } | |
804 | ||
805 | static void | |
806 | cleanup_handler(int sig) | |
807 | { | |
808 | cleanup_socket(); | |
809 | _exit(2); | |
810 | } | |
811 | ||
812 | static void | |
813 | check_parent_exists(int sig) | |
814 | { | |
815 | int save_errno = errno; | |
816 | ||
817 | if (parent_pid != -1 && kill(parent_pid, 0) < 0) { | |
818 | /* printf("Parent has died - Authentication agent exiting.\n"); */ | |
819 | cleanup_handler(sig); /* safe */ | |
820 | } | |
821 | signal(SIGALRM, check_parent_exists); | |
822 | alarm(10); | |
823 | errno = save_errno; | |
824 | } | |
825 | ||
826 | static void | |
827 | usage(void) | |
828 | { | |
829 | fprintf(stderr, "Usage: %s [options] [command [args ...]]\n", | |
830 | __progname); | |
831 | fprintf(stderr, "Options:\n"); | |
832 | fprintf(stderr, " -c Generate C-shell commands on stdout.\n"); | |
833 | fprintf(stderr, " -s Generate Bourne shell commands on stdout.\n"); | |
834 | fprintf(stderr, " -k Kill the current agent.\n"); | |
835 | fprintf(stderr, " -d Debug mode.\n"); | |
836 | exit(1); | |
837 | } | |
838 | ||
839 | int | |
840 | main(int ac, char **av) | |
841 | { | |
842 | int sock, c_flag = 0, d_flag = 0, k_flag = 0, s_flag = 0, ch, nalloc; | |
843 | struct sockaddr_un sunaddr; | |
844 | #ifdef HAVE_SETRLIMIT | |
845 | struct rlimit rlim; | |
846 | #endif | |
847 | #ifdef HAVE_CYGWIN | |
848 | int prev_mask; | |
849 | #endif | |
850 | pid_t pid; | |
851 | char *shell, *format, *pidstr, pidstrbuf[1 + 3 * sizeof pid]; | |
852 | extern int optind; | |
853 | fd_set *readsetp = NULL, *writesetp = NULL; | |
854 | ||
855 | SSLeay_add_all_algorithms(); | |
856 | ||
857 | __progname = get_progname(av[0]); | |
858 | init_rng(); | |
859 | seed_rng(); | |
860 | ||
861 | #ifdef __GNU_LIBRARY__ | |
862 | while ((ch = getopt(ac, av, "+cdks")) != -1) { | |
863 | #else /* __GNU_LIBRARY__ */ | |
864 | while ((ch = getopt(ac, av, "cdks")) != -1) { | |
865 | #endif /* __GNU_LIBRARY__ */ | |
866 | switch (ch) { | |
867 | case 'c': | |
868 | if (s_flag) | |
869 | usage(); | |
870 | c_flag++; | |
871 | break; | |
872 | case 'k': | |
873 | k_flag++; | |
874 | break; | |
875 | case 's': | |
876 | if (c_flag) | |
877 | usage(); | |
878 | s_flag++; | |
879 | break; | |
880 | case 'd': | |
881 | if (d_flag) | |
882 | usage(); | |
883 | d_flag++; | |
884 | break; | |
885 | default: | |
886 | usage(); | |
887 | } | |
888 | } | |
889 | ac -= optind; | |
890 | av += optind; | |
891 | ||
892 | if (ac > 0 && (c_flag || k_flag || s_flag || d_flag)) | |
893 | usage(); | |
894 | ||
895 | if (ac == 0 && !c_flag && !k_flag && !s_flag && !d_flag) { | |
896 | shell = getenv("SHELL"); | |
897 | if (shell != NULL && strncmp(shell + strlen(shell) - 3, "csh", 3) == 0) | |
898 | c_flag = 1; | |
899 | } | |
900 | if (k_flag) { | |
901 | pidstr = getenv(SSH_AGENTPID_ENV_NAME); | |
902 | if (pidstr == NULL) { | |
903 | fprintf(stderr, "%s not set, cannot kill agent\n", | |
904 | SSH_AGENTPID_ENV_NAME); | |
905 | exit(1); | |
906 | } | |
907 | pid = atoi(pidstr); | |
908 | if (pid < 1) { | |
909 | fprintf(stderr, "%s=\"%s\", which is not a good PID\n", | |
910 | SSH_AGENTPID_ENV_NAME, pidstr); | |
911 | exit(1); | |
912 | } | |
913 | if (kill(pid, SIGTERM) == -1) { | |
914 | perror("kill"); | |
915 | exit(1); | |
916 | } | |
917 | format = c_flag ? "unsetenv %s;\n" : "unset %s;\n"; | |
918 | printf(format, SSH_AUTHSOCKET_ENV_NAME); | |
919 | printf(format, SSH_AGENTPID_ENV_NAME); | |
920 | printf("echo Agent pid %d killed;\n", pid); | |
921 | exit(0); | |
922 | } | |
923 | parent_pid = getpid(); | |
924 | ||
925 | /* Create private directory for agent socket */ | |
926 | strlcpy(socket_dir, "/tmp/ssh-XXXXXXXX", sizeof socket_dir); | |
927 | if (mkdtemp(socket_dir) == NULL) { | |
928 | perror("mkdtemp: private socket dir"); | |
929 | exit(1); | |
930 | } | |
931 | snprintf(socket_name, sizeof socket_name, "%s/agent.%d", socket_dir, | |
932 | parent_pid); | |
933 | ||
934 | /* | |
935 | * Create socket early so it will exist before command gets run from | |
936 | * the parent. | |
937 | */ | |
938 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
939 | if (sock < 0) { | |
940 | perror("socket"); | |
941 | cleanup_exit(1); | |
942 | } | |
943 | memset(&sunaddr, 0, sizeof(sunaddr)); | |
944 | sunaddr.sun_family = AF_UNIX; | |
945 | strlcpy(sunaddr.sun_path, socket_name, sizeof(sunaddr.sun_path)); | |
946 | #ifdef HAVE_CYGWIN | |
947 | prev_mask = umask(0177); | |
948 | #endif | |
949 | if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) { | |
950 | perror("bind"); | |
951 | #ifdef HAVE_CYGWIN | |
952 | umask(prev_mask); | |
953 | #endif | |
954 | cleanup_exit(1); | |
955 | } | |
956 | #ifdef HAVE_CYGWIN | |
957 | umask(prev_mask); | |
958 | #endif | |
959 | if (listen(sock, 5) < 0) { | |
960 | perror("listen"); | |
961 | cleanup_exit(1); | |
962 | } | |
963 | ||
964 | /* | |
965 | * Fork, and have the parent execute the command, if any, or present | |
966 | * the socket data. The child continues as the authentication agent. | |
967 | */ | |
968 | if (d_flag) { | |
969 | log_init(__progname, SYSLOG_LEVEL_DEBUG1, SYSLOG_FACILITY_AUTH, 1); | |
970 | format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; | |
971 | printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, | |
972 | SSH_AUTHSOCKET_ENV_NAME); | |
973 | printf("echo Agent pid %d;\n", parent_pid); | |
974 | goto skip; | |
975 | } | |
976 | pid = fork(); | |
977 | if (pid == -1) { | |
978 | perror("fork"); | |
979 | exit(1); | |
980 | } | |
981 | if (pid != 0) { /* Parent - execute the given command. */ | |
982 | close(sock); | |
983 | snprintf(pidstrbuf, sizeof pidstrbuf, "%d", pid); | |
984 | if (ac == 0) { | |
985 | format = c_flag ? "setenv %s %s;\n" : "%s=%s; export %s;\n"; | |
986 | printf(format, SSH_AUTHSOCKET_ENV_NAME, socket_name, | |
987 | SSH_AUTHSOCKET_ENV_NAME); | |
988 | printf(format, SSH_AGENTPID_ENV_NAME, pidstrbuf, | |
989 | SSH_AGENTPID_ENV_NAME); | |
990 | printf("echo Agent pid %d;\n", pid); | |
991 | exit(0); | |
992 | } | |
993 | if (setenv(SSH_AUTHSOCKET_ENV_NAME, socket_name, 1) == -1 || | |
994 | setenv(SSH_AGENTPID_ENV_NAME, pidstrbuf, 1) == -1) { | |
995 | perror("setenv"); | |
996 | exit(1); | |
997 | } | |
998 | execvp(av[0], av); | |
999 | perror(av[0]); | |
1000 | exit(1); | |
1001 | } | |
1002 | ||
1003 | if (setsid() == -1) { | |
1004 | perror("setsid"); | |
1005 | cleanup_exit(1); | |
1006 | } | |
1007 | ||
1008 | (void)chdir("/"); | |
1009 | close(0); | |
1010 | close(1); | |
1011 | close(2); | |
1012 | ||
1013 | #ifdef HAVE_SETRLIMIT | |
1014 | /* deny core dumps, since memory contains unencrypted private keys */ | |
1015 | rlim.rlim_cur = rlim.rlim_max = 0; | |
1016 | if (setrlimit(RLIMIT_CORE, &rlim) < 0) { | |
1017 | perror("setrlimit rlimit_core failed"); | |
1018 | cleanup_exit(1); | |
1019 | } | |
1020 | #endif | |
1021 | ||
1022 | skip: | |
1023 | if (atexit(cleanup_socket) < 0) { | |
1024 | perror("atexit"); | |
1025 | cleanup_exit(1); | |
1026 | } | |
1027 | new_socket(AUTH_SOCKET, sock); | |
1028 | if (ac > 0) { | |
1029 | signal(SIGALRM, check_parent_exists); | |
1030 | alarm(10); | |
1031 | } | |
1032 | idtab_init(); | |
1033 | if (!d_flag) | |
1034 | signal(SIGINT, SIG_IGN); | |
1035 | signal(SIGPIPE, SIG_IGN); | |
1036 | signal(SIGHUP, cleanup_handler); | |
1037 | signal(SIGTERM, cleanup_handler); | |
1038 | nalloc = 0; | |
1039 | ||
1040 | while (1) { | |
1041 | prepare_select(&readsetp, &writesetp, &max_fd, &nalloc); | |
1042 | if (select(max_fd + 1, readsetp, writesetp, NULL, NULL) < 0) { | |
1043 | if (errno == EINTR) | |
1044 | continue; | |
1045 | exit(1); | |
1046 | } | |
1047 | after_select(readsetp, writesetp); | |
1048 | } | |
1049 | /* NOTREACHED */ | |
1050 | } |