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Commit | Line | Data |
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8efc0c15 | 1 | /* |
2 | ||
3 | authfd.c | |
4 | ||
5 | Author: Tatu Ylonen <ylo@cs.hut.fi> | |
6 | ||
7 | Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
8 | All rights reserved | |
9 | ||
10 | Created: Wed Mar 29 01:30:28 1995 ylo | |
11 | ||
12 | Functions for connecting the local authentication agent. | |
13 | ||
14 | */ | |
15 | ||
5881cd60 | 16 | #include "config.h" |
8efc0c15 | 17 | #include "includes.h" |
18 | RCSID("$Id$"); | |
19 | ||
20 | #include "ssh.h" | |
21 | #include "rsa.h" | |
22 | #include "authfd.h" | |
23 | #include "buffer.h" | |
24 | #include "bufaux.h" | |
25 | #include "xmalloc.h" | |
26 | #include "getput.h" | |
27 | ||
5881cd60 | 28 | #ifdef HAVE_OPENSSL |
8efc0c15 | 29 | #include <openssl/rsa.h> |
5881cd60 | 30 | #endif |
31 | #ifdef HAVE_SSL | |
32 | #include <ssl/rsa.h> | |
33 | #endif | |
8efc0c15 | 34 | |
35 | /* Returns the number of the authentication fd, or -1 if there is none. */ | |
36 | ||
37 | int | |
38 | ssh_get_authentication_socket() | |
39 | { | |
40 | const char *authsocket; | |
41 | int sock; | |
42 | struct sockaddr_un sunaddr; | |
43 | ||
44 | authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME); | |
45 | if (!authsocket) | |
46 | return -1; | |
47 | ||
48 | sunaddr.sun_family = AF_UNIX; | |
49 | strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path)); | |
50 | ||
51 | sock = socket(AF_UNIX, SOCK_STREAM, 0); | |
52 | if (sock < 0) | |
53 | return -1; | |
54 | ||
55 | if (connect(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) | |
56 | { | |
57 | close(sock); | |
58 | return -1; | |
59 | } | |
60 | ||
61 | return sock; | |
62 | } | |
63 | ||
64 | /* Closes the agent socket if it should be closed (depends on how it was | |
65 | obtained). The argument must have been returned by | |
66 | ssh_get_authentication_socket(). */ | |
67 | ||
68 | void ssh_close_authentication_socket(int sock) | |
69 | { | |
70 | if (getenv(SSH_AUTHSOCKET_ENV_NAME)) | |
71 | close(sock); | |
72 | } | |
73 | ||
74 | /* Opens and connects a private socket for communication with the | |
75 | authentication agent. Returns the file descriptor (which must be | |
76 | shut down and closed by the caller when no longer needed). | |
77 | Returns NULL if an error occurred and the connection could not be | |
78 | opened. */ | |
79 | ||
80 | AuthenticationConnection *ssh_get_authentication_connection() | |
81 | { | |
82 | AuthenticationConnection *auth; | |
83 | int sock; | |
84 | ||
85 | sock = ssh_get_authentication_socket(); | |
86 | ||
87 | /* Fail if we couldn't obtain a connection. This happens if we exited | |
88 | due to a timeout. */ | |
89 | if (sock < 0) | |
90 | return NULL; | |
91 | ||
92 | /* Applocate the connection structure and initialize it. */ | |
93 | auth = xmalloc(sizeof(*auth)); | |
94 | auth->fd = sock; | |
95 | buffer_init(&auth->packet); | |
96 | buffer_init(&auth->identities); | |
97 | auth->howmany = 0; | |
98 | ||
99 | return auth; | |
100 | } | |
101 | ||
102 | /* Closes the connection to the authentication agent and frees any associated | |
103 | memory. */ | |
104 | ||
105 | void ssh_close_authentication_connection(AuthenticationConnection *ac) | |
106 | { | |
107 | buffer_free(&ac->packet); | |
108 | buffer_free(&ac->identities); | |
109 | close(ac->fd); | |
110 | /* Free the connection data structure. */ | |
111 | xfree(ac); | |
112 | } | |
113 | ||
114 | /* Returns the first authentication identity held by the agent. | |
115 | Returns true if an identity is available, 0 otherwise. | |
116 | The caller must initialize the integers before the call, and free the | |
117 | comment after a successful call (before calling ssh_get_next_identity). */ | |
118 | ||
119 | int | |
120 | ssh_get_first_identity(AuthenticationConnection *auth, | |
121 | int *bitsp, BIGNUM *e, BIGNUM *n, char **comment) | |
122 | { | |
123 | unsigned char msg[8192]; | |
124 | int len, l; | |
125 | ||
126 | /* Send a message to the agent requesting for a list of the identities | |
127 | it can represent. */ | |
128 | msg[0] = 0; | |
129 | msg[1] = 0; | |
130 | msg[2] = 0; | |
131 | msg[3] = 1; | |
132 | msg[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES; | |
133 | if (write(auth->fd, msg, 5) != 5) | |
134 | { | |
135 | error("write auth->fd: %.100s", strerror(errno)); | |
136 | return 0; | |
137 | } | |
138 | ||
139 | /* Read the length of the response. XXX implement timeouts here. */ | |
140 | len = 4; | |
141 | while (len > 0) | |
142 | { | |
143 | l = read(auth->fd, msg + 4 - len, len); | |
144 | if (l <= 0) | |
145 | { | |
146 | error("read auth->fd: %.100s", strerror(errno)); | |
147 | return 0; | |
148 | } | |
149 | len -= l; | |
150 | } | |
151 | ||
152 | /* Extract the length, and check it for sanity. (We cannot trust | |
153 | authentication agents). */ | |
154 | len = GET_32BIT(msg); | |
155 | if (len < 1 || len > 256*1024) | |
156 | fatal("Authentication reply message too long: %d\n", len); | |
157 | ||
158 | /* Read the packet itself. */ | |
159 | buffer_clear(&auth->identities); | |
160 | while (len > 0) | |
161 | { | |
162 | l = len; | |
163 | if (l > sizeof(msg)) | |
164 | l = sizeof(msg); | |
165 | l = read(auth->fd, msg, l); | |
166 | if (l <= 0) | |
167 | fatal("Incomplete authentication reply."); | |
168 | buffer_append(&auth->identities, (char *)msg, l); | |
169 | len -= l; | |
170 | } | |
171 | ||
172 | /* Get message type, and verify that we got a proper answer. */ | |
173 | buffer_get(&auth->identities, (char *)msg, 1); | |
174 | if (msg[0] != SSH_AGENT_RSA_IDENTITIES_ANSWER) | |
175 | fatal("Bad authentication reply message type: %d", msg[0]); | |
176 | ||
177 | /* Get the number of entries in the response and check it for sanity. */ | |
178 | auth->howmany = buffer_get_int(&auth->identities); | |
179 | if (auth->howmany > 1024) | |
180 | fatal("Too many identities in authentication reply: %d\n", auth->howmany); | |
181 | ||
182 | /* Return the first entry (if any). */ | |
183 | return ssh_get_next_identity(auth, bitsp, e, n, comment); | |
184 | } | |
185 | ||
186 | /* Returns the next authentication identity for the agent. Other functions | |
187 | can be called between this and ssh_get_first_identity or two calls of this | |
188 | function. This returns 0 if there are no more identities. The caller | |
189 | must free comment after a successful return. */ | |
190 | ||
191 | int | |
192 | ssh_get_next_identity(AuthenticationConnection *auth, | |
193 | int *bitsp, BIGNUM *e, BIGNUM *n, char **comment) | |
194 | { | |
195 | /* Return failure if no more entries. */ | |
196 | if (auth->howmany <= 0) | |
197 | return 0; | |
198 | ||
199 | /* Get the next entry from the packet. These will abort with a fatal | |
200 | error if the packet is too short or contains corrupt data. */ | |
201 | *bitsp = buffer_get_int(&auth->identities); | |
202 | buffer_get_bignum(&auth->identities, e); | |
203 | buffer_get_bignum(&auth->identities, n); | |
204 | *comment = buffer_get_string(&auth->identities, NULL); | |
205 | ||
206 | /* Decrement the number of remaining entries. */ | |
207 | auth->howmany--; | |
208 | ||
209 | return 1; | |
210 | } | |
211 | ||
212 | /* Generates a random challenge, sends it to the agent, and waits for response | |
213 | from the agent. Returns true (non-zero) if the agent gave the correct | |
214 | answer, zero otherwise. Response type selects the style of response | |
215 | desired, with 0 corresponding to protocol version 1.0 (no longer supported) | |
216 | and 1 corresponding to protocol version 1.1. */ | |
217 | ||
218 | int | |
219 | ssh_decrypt_challenge(AuthenticationConnection *auth, | |
220 | int bits, BIGNUM *e, BIGNUM *n, BIGNUM *challenge, | |
221 | unsigned char session_id[16], | |
222 | unsigned int response_type, | |
223 | unsigned char response[16]) | |
224 | { | |
225 | Buffer buffer; | |
226 | unsigned char buf[8192]; | |
227 | int len, l, i; | |
228 | ||
229 | /* Response type 0 is no longer supported. */ | |
230 | if (response_type == 0) | |
231 | fatal("Compatibility with ssh protocol version 1.0 no longer supported."); | |
232 | ||
233 | /* Format a message to the agent. */ | |
234 | buf[0] = SSH_AGENTC_RSA_CHALLENGE; | |
235 | buffer_init(&buffer); | |
236 | buffer_append(&buffer, (char *)buf, 1); | |
237 | buffer_put_int(&buffer, bits); | |
238 | buffer_put_bignum(&buffer, e); | |
239 | buffer_put_bignum(&buffer, n); | |
240 | buffer_put_bignum(&buffer, challenge); | |
241 | buffer_append(&buffer, (char *)session_id, 16); | |
242 | buffer_put_int(&buffer, response_type); | |
243 | ||
244 | /* Get the length of the message, and format it in the buffer. */ | |
245 | len = buffer_len(&buffer); | |
246 | PUT_32BIT(buf, len); | |
247 | ||
248 | /* Send the length and then the packet to the agent. */ | |
249 | if (write(auth->fd, buf, 4) != 4 || | |
250 | write(auth->fd, buffer_ptr(&buffer), buffer_len(&buffer)) != | |
251 | buffer_len(&buffer)) | |
252 | { | |
253 | error("Error writing to authentication socket."); | |
254 | error_cleanup: | |
255 | buffer_free(&buffer); | |
256 | return 0; | |
257 | } | |
258 | ||
259 | /* Wait for response from the agent. First read the length of the | |
260 | response packet. */ | |
261 | len = 4; | |
262 | while (len > 0) | |
263 | { | |
264 | l = read(auth->fd, buf + 4 - len, len); | |
265 | if (l <= 0) | |
266 | { | |
267 | error("Error reading response length from authentication socket."); | |
268 | goto error_cleanup; | |
269 | } | |
270 | len -= l; | |
271 | } | |
272 | ||
273 | /* Extract the length, and check it for sanity. */ | |
274 | len = GET_32BIT(buf); | |
275 | if (len > 256*1024) | |
276 | fatal("Authentication response too long: %d", len); | |
277 | ||
278 | /* Read the rest of the response in tothe buffer. */ | |
279 | buffer_clear(&buffer); | |
280 | while (len > 0) | |
281 | { | |
282 | l = len; | |
283 | if (l > sizeof(buf)) | |
284 | l = sizeof(buf); | |
285 | l = read(auth->fd, buf, l); | |
286 | if (l <= 0) | |
287 | { | |
288 | error("Error reading response from authentication socket."); | |
289 | goto error_cleanup; | |
290 | } | |
291 | buffer_append(&buffer, (char *)buf, l); | |
292 | len -= l; | |
293 | } | |
294 | ||
295 | /* Get the type of the packet. */ | |
296 | buffer_get(&buffer, (char *)buf, 1); | |
297 | ||
298 | /* Check for agent failure message. */ | |
299 | if (buf[0] == SSH_AGENT_FAILURE) | |
300 | { | |
301 | log("Agent admitted failure to authenticate using the key."); | |
302 | goto error_cleanup; | |
303 | } | |
304 | ||
305 | /* Now it must be an authentication response packet. */ | |
306 | if (buf[0] != SSH_AGENT_RSA_RESPONSE) | |
307 | fatal("Bad authentication response: %d", buf[0]); | |
308 | ||
309 | /* Get the response from the packet. This will abort with a fatal error | |
310 | if the packet is corrupt. */ | |
311 | for (i = 0; i < 16; i++) | |
312 | response[i] = buffer_get_char(&buffer); | |
313 | ||
314 | /* The buffer containing the packet is no longer needed. */ | |
315 | buffer_free(&buffer); | |
316 | ||
317 | /* Correct answer. */ | |
318 | return 1; | |
319 | } | |
320 | ||
321 | /* Adds an identity to the authentication server. This call is not meant to | |
322 | be used by normal applications. */ | |
323 | ||
324 | int ssh_add_identity(AuthenticationConnection *auth, | |
325 | RSA *key, const char *comment) | |
326 | { | |
327 | Buffer buffer; | |
328 | unsigned char buf[8192]; | |
329 | int len, l, type; | |
330 | ||
331 | /* Format a message to the agent. */ | |
332 | buffer_init(&buffer); | |
333 | buffer_put_char(&buffer, SSH_AGENTC_ADD_RSA_IDENTITY); | |
334 | buffer_put_int(&buffer, BN_num_bits(key->n)); | |
335 | buffer_put_bignum(&buffer, key->n); | |
336 | buffer_put_bignum(&buffer, key->e); | |
337 | buffer_put_bignum(&buffer, key->d); | |
338 | /* To keep within the protocol: p < q for ssh. in SSL p > q */ | |
339 | buffer_put_bignum(&buffer, key->iqmp); /* ssh key->u */ | |
340 | buffer_put_bignum(&buffer, key->q); /* ssh key->p, SSL key->q */ | |
341 | buffer_put_bignum(&buffer, key->p); /* ssh key->q, SSL key->p */ | |
342 | buffer_put_string(&buffer, comment, strlen(comment)); | |
343 | ||
344 | /* Get the length of the message, and format it in the buffer. */ | |
345 | len = buffer_len(&buffer); | |
346 | PUT_32BIT(buf, len); | |
347 | ||
348 | /* Send the length and then the packet to the agent. */ | |
349 | if (write(auth->fd, buf, 4) != 4 || | |
350 | write(auth->fd, buffer_ptr(&buffer), buffer_len(&buffer)) != | |
351 | buffer_len(&buffer)) | |
352 | { | |
353 | error("Error writing to authentication socket."); | |
354 | error_cleanup: | |
355 | buffer_free(&buffer); | |
356 | return 0; | |
357 | } | |
358 | ||
359 | /* Wait for response from the agent. First read the length of the | |
360 | response packet. */ | |
361 | len = 4; | |
362 | while (len > 0) | |
363 | { | |
364 | l = read(auth->fd, buf + 4 - len, len); | |
365 | if (l <= 0) | |
366 | { | |
367 | error("Error reading response length from authentication socket."); | |
368 | goto error_cleanup; | |
369 | } | |
370 | len -= l; | |
371 | } | |
372 | ||
373 | /* Extract the length, and check it for sanity. */ | |
374 | len = GET_32BIT(buf); | |
375 | if (len > 256*1024) | |
376 | fatal("Add identity response too long: %d", len); | |
377 | ||
378 | /* Read the rest of the response in tothe buffer. */ | |
379 | buffer_clear(&buffer); | |
380 | while (len > 0) | |
381 | { | |
382 | l = len; | |
383 | if (l > sizeof(buf)) | |
384 | l = sizeof(buf); | |
385 | l = read(auth->fd, buf, l); | |
386 | if (l <= 0) | |
387 | { | |
388 | error("Error reading response from authentication socket."); | |
389 | goto error_cleanup; | |
390 | } | |
391 | buffer_append(&buffer, (char *)buf, l); | |
392 | len -= l; | |
393 | } | |
394 | ||
395 | /* Get the type of the packet. */ | |
396 | type = buffer_get_char(&buffer); | |
397 | switch (type) | |
398 | { | |
399 | case SSH_AGENT_FAILURE: | |
400 | buffer_free(&buffer); | |
401 | return 0; | |
402 | case SSH_AGENT_SUCCESS: | |
403 | buffer_free(&buffer); | |
404 | return 1; | |
405 | default: | |
406 | fatal("Bad response to add identity from authentication agent: %d", | |
407 | type); | |
408 | } | |
409 | /*NOTREACHED*/ | |
410 | return 0; | |
411 | } | |
412 | ||
413 | /* Removes an identity from the authentication server. This call is not meant | |
414 | to be used by normal applications. */ | |
415 | ||
416 | int ssh_remove_identity(AuthenticationConnection *auth, RSA *key) | |
417 | { | |
418 | Buffer buffer; | |
419 | unsigned char buf[8192]; | |
420 | int len, l, type; | |
421 | ||
422 | /* Format a message to the agent. */ | |
423 | buffer_init(&buffer); | |
424 | buffer_put_char(&buffer, SSH_AGENTC_REMOVE_RSA_IDENTITY); | |
425 | buffer_put_int(&buffer, BN_num_bits(key->n)); | |
426 | buffer_put_bignum(&buffer, key->e); | |
427 | buffer_put_bignum(&buffer, key->n); | |
428 | ||
429 | /* Get the length of the message, and format it in the buffer. */ | |
430 | len = buffer_len(&buffer); | |
431 | PUT_32BIT(buf, len); | |
432 | ||
433 | /* Send the length and then the packet to the agent. */ | |
434 | if (write(auth->fd, buf, 4) != 4 || | |
435 | write(auth->fd, buffer_ptr(&buffer), buffer_len(&buffer)) != | |
436 | buffer_len(&buffer)) | |
437 | { | |
438 | error("Error writing to authentication socket."); | |
439 | error_cleanup: | |
440 | buffer_free(&buffer); | |
441 | return 0; | |
442 | } | |
443 | ||
444 | /* Wait for response from the agent. First read the length of the | |
445 | response packet. */ | |
446 | len = 4; | |
447 | while (len > 0) | |
448 | { | |
449 | l = read(auth->fd, buf + 4 - len, len); | |
450 | if (l <= 0) | |
451 | { | |
452 | error("Error reading response length from authentication socket."); | |
453 | goto error_cleanup; | |
454 | } | |
455 | len -= l; | |
456 | } | |
457 | ||
458 | /* Extract the length, and check it for sanity. */ | |
459 | len = GET_32BIT(buf); | |
460 | if (len > 256*1024) | |
461 | fatal("Remove identity response too long: %d", len); | |
462 | ||
463 | /* Read the rest of the response in tothe buffer. */ | |
464 | buffer_clear(&buffer); | |
465 | while (len > 0) | |
466 | { | |
467 | l = len; | |
468 | if (l > sizeof(buf)) | |
469 | l = sizeof(buf); | |
470 | l = read(auth->fd, buf, l); | |
471 | if (l <= 0) | |
472 | { | |
473 | error("Error reading response from authentication socket."); | |
474 | goto error_cleanup; | |
475 | } | |
476 | buffer_append(&buffer, (char *)buf, l); | |
477 | len -= l; | |
478 | } | |
479 | ||
480 | /* Get the type of the packet. */ | |
481 | type = buffer_get_char(&buffer); | |
482 | switch (type) | |
483 | { | |
484 | case SSH_AGENT_FAILURE: | |
485 | buffer_free(&buffer); | |
486 | return 0; | |
487 | case SSH_AGENT_SUCCESS: | |
488 | buffer_free(&buffer); | |
489 | return 1; | |
490 | default: | |
491 | fatal("Bad response to remove identity from authentication agent: %d", | |
492 | type); | |
493 | } | |
494 | /*NOTREACHED*/ | |
495 | return 0; | |
496 | } | |
497 | ||
498 | /* Removes all identities from the agent. This call is not meant | |
499 | to be used by normal applications. */ | |
500 | ||
501 | int ssh_remove_all_identities(AuthenticationConnection *auth) | |
502 | { | |
503 | Buffer buffer; | |
504 | unsigned char buf[8192]; | |
505 | int len, l, type; | |
506 | ||
507 | /* Get the length of the message, and format it in the buffer. */ | |
508 | PUT_32BIT(buf, 1); | |
509 | buf[4] = SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES; | |
510 | ||
511 | /* Send the length and then the packet to the agent. */ | |
512 | if (write(auth->fd, buf, 5) != 5) | |
513 | { | |
514 | error("Error writing to authentication socket."); | |
515 | return 0; | |
516 | } | |
517 | ||
518 | /* Wait for response from the agent. First read the length of the | |
519 | response packet. */ | |
520 | len = 4; | |
521 | while (len > 0) | |
522 | { | |
523 | l = read(auth->fd, buf + 4 - len, len); | |
524 | if (l <= 0) | |
525 | { | |
526 | error("Error reading response length from authentication socket."); | |
527 | return 0; | |
528 | } | |
529 | len -= l; | |
530 | } | |
531 | ||
532 | /* Extract the length, and check it for sanity. */ | |
533 | len = GET_32BIT(buf); | |
534 | if (len > 256*1024) | |
535 | fatal("Remove identity response too long: %d", len); | |
536 | ||
537 | /* Read the rest of the response into the buffer. */ | |
538 | buffer_init(&buffer); | |
539 | while (len > 0) | |
540 | { | |
541 | l = len; | |
542 | if (l > sizeof(buf)) | |
543 | l = sizeof(buf); | |
544 | l = read(auth->fd, buf, l); | |
545 | if (l <= 0) | |
546 | { | |
547 | error("Error reading response from authentication socket."); | |
548 | buffer_free(&buffer); | |
549 | return 0; | |
550 | } | |
551 | buffer_append(&buffer, (char *)buf, l); | |
552 | len -= l; | |
553 | } | |
554 | ||
555 | /* Get the type of the packet. */ | |
556 | type = buffer_get_char(&buffer); | |
557 | switch (type) | |
558 | { | |
559 | case SSH_AGENT_FAILURE: | |
560 | buffer_free(&buffer); | |
561 | return 0; | |
562 | case SSH_AGENT_SUCCESS: | |
563 | buffer_free(&buffer); | |
564 | return 1; | |
565 | default: | |
566 | fatal("Bad response to remove identity from authentication agent: %d", | |
567 | type); | |
568 | } | |
569 | /*NOTREACHED*/ | |
570 | return 0; | |
571 | } |