1 /* $OpenBSD: ssh-add.c,v 1.120 2015/02/21 21:46:57 halex Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * Adds an identity to the authentication server, or removes an identity.
7 *
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
13 *
14 * SSH2 implementation,
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
40 #include <sys/types.h>
41 #include <sys/stat.h>
42
43 #include <openssl/evp.h>
44 #include "openbsd-compat/openssl-compat.h"
45
46 #include <errno.h>
47 #include <fcntl.h>
48 #include <pwd.h>
49 #include <stdarg.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54 #include <limits.h>
55
56 #include "xmalloc.h"
57 #include "ssh.h"
58 #include "rsa.h"
59 #include "log.h"
60 #include "sshkey.h"
61 #include "sshbuf.h"
62 #include "authfd.h"
63 #include "authfile.h"
64 #include "pathnames.h"
65 #include "misc.h"
66 #include "ssherr.h"
67 #include "digest.h"
68
69 /* argv0 */
70 extern char *__progname;
71
72 /* Default files to add */
73 static char *default_files[] = {
74 #ifdef WITH_OPENSSL
75 _PATH_SSH_CLIENT_ID_RSA,
76 _PATH_SSH_CLIENT_ID_DSA,
77 #ifdef OPENSSL_HAS_ECC
78 _PATH_SSH_CLIENT_ID_ECDSA,
79 #endif
80 #endif /* WITH_OPENSSL */
81 _PATH_SSH_CLIENT_ID_ED25519,
82 _PATH_SSH_CLIENT_IDENTITY,
83 NULL
84 };
85
86 static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
87
88 /* Default lifetime (0 == forever) */
89 static int lifetime = 0;
90
91 /* User has to confirm key use */
92 static int confirm = 0;
93
94 /* we keep a cache of one passphrases */
95 static char *pass = NULL;
96 static void
clear_pass(void)97 clear_pass(void)
98 {
99 if (pass) {
100 explicit_bzero(pass, strlen(pass));
101 free(pass);
102 pass = NULL;
103 }
104 }
105
106 static int
delete_file(int agent_fd,const char * filename,int key_only)107 delete_file(int agent_fd, const char *filename, int key_only)
108 {
109 struct sshkey *public, *cert = NULL;
110 char *certpath = NULL, *comment = NULL;
111 int r, ret = -1;
112
113 if ((r = sshkey_load_public(filename, &public, &comment)) != 0) {
114 printf("Bad key file %s: %s\n", filename, ssh_err(r));
115 return -1;
116 }
117 if ((r = ssh_remove_identity(agent_fd, public)) == 0) {
118 fprintf(stderr, "Identity removed: %s (%s)\n", filename, comment);
119 ret = 0;
120 } else
121 fprintf(stderr, "Could not remove identity \"%s\": %s\n",
122 filename, ssh_err(r));
123
124 if (key_only)
125 goto out;
126
127 /* Now try to delete the corresponding certificate too */
128 free(comment);
129 comment = NULL;
130 xasprintf(&certpath, "%s-cert.pub", filename);
131 if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) {
132 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
133 error("Failed to load certificate \"%s\": %s",
134 certpath, ssh_err(r));
135 goto out;
136 }
137
138 if (!sshkey_equal_public(cert, public))
139 fatal("Certificate %s does not match private key %s",
140 certpath, filename);
141
142 if ((r = ssh_remove_identity(agent_fd, cert)) == 0) {
143 fprintf(stderr, "Identity removed: %s (%s)\n", certpath,
144 comment);
145 ret = 0;
146 } else
147 fprintf(stderr, "Could not remove identity \"%s\": %s\n",
148 certpath, ssh_err(r));
149
150 out:
151 if (cert != NULL)
152 sshkey_free(cert);
153 if (public != NULL)
154 sshkey_free(public);
155 free(certpath);
156 free(comment);
157
158 return ret;
159 }
160
161 /* Send a request to remove all identities. */
162 static int
delete_all(int agent_fd)163 delete_all(int agent_fd)
164 {
165 int ret = -1;
166
167 if (ssh_remove_all_identities(agent_fd, 1) == 0)
168 ret = 0;
169 /* ignore error-code for ssh2 */
170 /* XXX revisit */
171 ssh_remove_all_identities(agent_fd, 2);
172
173 if (ret == 0)
174 fprintf(stderr, "All identities removed.\n");
175 else
176 fprintf(stderr, "Failed to remove all identities.\n");
177
178 return ret;
179 }
180
181 static int
add_file(int agent_fd,const char * filename,int key_only)182 add_file(int agent_fd, const char *filename, int key_only)
183 {
184 struct sshkey *private, *cert;
185 char *comment = NULL;
186 char msg[1024], *certpath = NULL;
187 int r, fd, ret = -1;
188 struct sshbuf *keyblob;
189
190 if (strcmp(filename, "-") == 0) {
191 fd = STDIN_FILENO;
192 filename = "(stdin)";
193 } else if ((fd = open(filename, O_RDONLY)) < 0) {
194 perror(filename);
195 return -1;
196 }
197
198 /*
199 * Since we'll try to load a keyfile multiple times, permission errors
200 * will occur multiple times, so check perms first and bail if wrong.
201 */
202 if (fd != STDIN_FILENO) {
203 if (sshkey_perm_ok(fd, filename) != 0) {
204 close(fd);
205 return -1;
206 }
207 }
208 if ((keyblob = sshbuf_new()) == NULL)
209 fatal("%s: sshbuf_new failed", __func__);
210 if ((r = sshkey_load_file(fd, keyblob)) != 0) {
211 fprintf(stderr, "Error loading key \"%s\": %s\n",
212 filename, ssh_err(r));
213 sshbuf_free(keyblob);
214 close(fd);
215 return -1;
216 }
217 close(fd);
218
219 /* At first, try empty passphrase */
220 if ((r = sshkey_parse_private_fileblob(keyblob, "", filename,
221 &private, &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
222 fprintf(stderr, "Error loading key \"%s\": %s\n",
223 filename, ssh_err(r));
224 goto fail_load;
225 }
226 /* try last */
227 if (private == NULL && pass != NULL) {
228 if ((r = sshkey_parse_private_fileblob(keyblob, pass, filename,
229 &private, &comment)) != 0 &&
230 r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
231 fprintf(stderr, "Error loading key \"%s\": %s\n",
232 filename, ssh_err(r));
233 goto fail_load;
234 }
235 }
236 if (comment == NULL)
237 comment = xstrdup(filename);
238 if (private == NULL) {
239 /* clear passphrase since it did not work */
240 clear_pass();
241 snprintf(msg, sizeof msg, "Enter passphrase for %.200s%s: ",
242 comment, confirm ? " (will confirm each use)" : "");
243 for (;;) {
244 pass = read_passphrase(msg, RP_ALLOW_STDIN);
245 if (strcmp(pass, "") == 0)
246 goto fail_load;
247 if ((r = sshkey_parse_private_fileblob(keyblob, pass,
248 filename, &private, NULL)) == 0)
249 break;
250 else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
251 fprintf(stderr,
252 "Error loading key \"%s\": %s\n",
253 filename, ssh_err(r));
254 fail_load:
255 clear_pass();
256 free(comment);
257 sshbuf_free(keyblob);
258 return -1;
259 }
260 clear_pass();
261 snprintf(msg, sizeof msg,
262 "Bad passphrase, try again for %.200s%s: ", comment,
263 confirm ? " (will confirm each use)" : "");
264 }
265 }
266 sshbuf_free(keyblob);
267
268 if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
269 lifetime, confirm)) == 0) {
270 fprintf(stderr, "Identity added: %s (%s)\n", filename, comment);
271 ret = 0;
272 if (lifetime != 0)
273 fprintf(stderr,
274 "Lifetime set to %d seconds\n", lifetime);
275 if (confirm != 0)
276 fprintf(stderr,
277 "The user must confirm each use of the key\n");
278 } else {
279 fprintf(stderr, "Could not add identity \"%s\": %s\n",
280 filename, ssh_err(r));
281 }
282
283 /* Skip trying to load the cert if requested */
284 if (key_only)
285 goto out;
286
287 /* Now try to add the certificate flavour too */
288 xasprintf(&certpath, "%s-cert.pub", filename);
289 if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) {
290 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
291 error("Failed to load certificate \"%s\": %s",
292 certpath, ssh_err(r));
293 goto out;
294 }
295
296 if (!sshkey_equal_public(cert, private)) {
297 error("Certificate %s does not match private key %s",
298 certpath, filename);
299 sshkey_free(cert);
300 goto out;
301 }
302
303 /* Graft with private bits */
304 if ((r = sshkey_to_certified(private,
305 sshkey_cert_is_legacy(cert))) != 0) {
306 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r));
307 sshkey_free(cert);
308 goto out;
309 }
310 if ((r = sshkey_cert_copy(cert, private)) != 0) {
311 error("%s: key_cert_copy: %s", __func__, ssh_err(r));
312 sshkey_free(cert);
313 goto out;
314 }
315 sshkey_free(cert);
316
317 if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
318 lifetime, confirm)) != 0) {
319 error("Certificate %s (%s) add failed: %s", certpath,
320 private->cert->key_id, ssh_err(r));
321 goto out;
322 }
323 fprintf(stderr, "Certificate added: %s (%s)\n", certpath,
324 private->cert->key_id);
325 if (lifetime != 0)
326 fprintf(stderr, "Lifetime set to %d seconds\n", lifetime);
327 if (confirm != 0)
328 fprintf(stderr, "The user must confirm each use of the key\n");
329 out:
330 free(certpath);
331 free(comment);
332 sshkey_free(private);
333
334 return ret;
335 }
336
337 static int
update_card(int agent_fd,int add,const char * id)338 update_card(int agent_fd, int add, const char *id)
339 {
340 char *pin = NULL;
341 int r, ret = -1;
342
343 if (add) {
344 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ",
345 RP_ALLOW_STDIN)) == NULL)
346 return -1;
347 }
348
349 if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin,
350 lifetime, confirm)) == 0) {
351 fprintf(stderr, "Card %s: %s\n",
352 add ? "added" : "removed", id);
353 ret = 0;
354 } else {
355 fprintf(stderr, "Could not %s card \"%s\": %s\n",
356 add ? "add" : "remove", id, ssh_err(r));
357 ret = -1;
358 }
359 free(pin);
360 return ret;
361 }
362
363 static int
list_identities(int agent_fd,int do_fp)364 list_identities(int agent_fd, int do_fp)
365 {
366 char *fp;
367 int version, r, had_identities = 0;
368 struct ssh_identitylist *idlist;
369 size_t i;
370
371 for (version = 1; version <= 2; version++) {
372 if ((r = ssh_fetch_identitylist(agent_fd, version,
373 &idlist)) != 0) {
374 if (r != SSH_ERR_AGENT_NO_IDENTITIES)
375 fprintf(stderr, "error fetching identities for "
376 "protocol %d: %s\n", version, ssh_err(r));
377 continue;
378 }
379 for (i = 0; i < idlist->nkeys; i++) {
380 had_identities = 1;
381 if (do_fp) {
382 fp = sshkey_fingerprint(idlist->keys[i],
383 fingerprint_hash, SSH_FP_DEFAULT);
384 printf("%d %s %s (%s)\n",
385 sshkey_size(idlist->keys[i]),
386 fp == NULL ? "(null)" : fp,
387 idlist->comments[i],
388 sshkey_type(idlist->keys[i]));
389 free(fp);
390 } else {
391 if ((r = sshkey_write(idlist->keys[i],
392 stdout)) != 0) {
393 fprintf(stderr, "sshkey_write: %s\n",
394 ssh_err(r));
395 continue;
396 }
397 fprintf(stdout, " %s\n", idlist->comments[i]);
398 }
399 }
400 ssh_free_identitylist(idlist);
401 }
402 if (!had_identities) {
403 printf("The agent has no identities.\n");
404 return -1;
405 }
406 return 0;
407 }
408
409 static int
lock_agent(int agent_fd,int lock)410 lock_agent(int agent_fd, int lock)
411 {
412 char prompt[100], *p1, *p2;
413 int r, passok = 1, ret = -1;
414
415 strlcpy(prompt, "Enter lock password: ", sizeof(prompt));
416 p1 = read_passphrase(prompt, RP_ALLOW_STDIN);
417 if (lock) {
418 strlcpy(prompt, "Again: ", sizeof prompt);
419 p2 = read_passphrase(prompt, RP_ALLOW_STDIN);
420 if (strcmp(p1, p2) != 0) {
421 fprintf(stderr, "Passwords do not match.\n");
422 passok = 0;
423 }
424 explicit_bzero(p2, strlen(p2));
425 free(p2);
426 }
427 if (passok) {
428 if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) {
429 fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un");
430 ret = 0;
431 } else {
432 fprintf(stderr, "Failed to %slock agent: %s\n",
433 lock ? "" : "un", ssh_err(r));
434 }
435 }
436 explicit_bzero(p1, strlen(p1));
437 free(p1);
438 return (ret);
439 }
440
441 static int
do_file(int agent_fd,int deleting,int key_only,char * file)442 do_file(int agent_fd, int deleting, int key_only, char *file)
443 {
444 if (deleting) {
445 if (delete_file(agent_fd, file, key_only) == -1)
446 return -1;
447 } else {
448 if (add_file(agent_fd, file, key_only) == -1)
449 return -1;
450 }
451 return 0;
452 }
453
454 static void
usage(void)455 usage(void)
456 {
457 fprintf(stderr, "usage: %s [options] [file ...]\n", __progname);
458 fprintf(stderr, "Options:\n");
459 fprintf(stderr, " -l List fingerprints of all identities.\n");
460 fprintf(stderr, " -E hash Specify hash algorithm used for fingerprints.\n");
461 fprintf(stderr, " -L List public key parameters of all identities.\n");
462 fprintf(stderr, " -k Load only keys and not certificates.\n");
463 fprintf(stderr, " -c Require confirmation to sign using identities\n");
464 fprintf(stderr, " -t life Set lifetime (in seconds) when adding identities.\n");
465 fprintf(stderr, " -d Delete identity.\n");
466 fprintf(stderr, " -D Delete all identities.\n");
467 fprintf(stderr, " -x Lock agent.\n");
468 fprintf(stderr, " -X Unlock agent.\n");
469 fprintf(stderr, " -s pkcs11 Add keys from PKCS#11 provider.\n");
470 fprintf(stderr, " -e pkcs11 Remove keys provided by PKCS#11 provider.\n");
471 }
472
473 int
main(int argc,char ** argv)474 main(int argc, char **argv)
475 {
476 extern char *optarg;
477 extern int optind;
478 int agent_fd;
479 char *pkcs11provider = NULL;
480 int r, i, ch, deleting = 0, ret = 0, key_only = 0;
481 int xflag = 0, lflag = 0, Dflag = 0;
482
483 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
484 sanitise_stdfd();
485
486 __progname = ssh_get_progname(argv[0]);
487 seed_rng();
488
489 #ifdef WITH_OPENSSL
490 OpenSSL_add_all_algorithms();
491 #endif
492
493 setvbuf(stdout, NULL, _IOLBF, 0);
494
495 /* First, get a connection to the authentication agent. */
496 switch (r = ssh_get_authentication_socket(&agent_fd)) {
497 case 0:
498 break;
499 case SSH_ERR_AGENT_NOT_PRESENT:
500 fprintf(stderr, "Could not open a connection to your "
501 "authentication agent.\n");
502 exit(2);
503 default:
504 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r));
505 exit(2);
506 }
507
508 while ((ch = getopt(argc, argv, "klLcdDxXE:e:s:t:")) != -1) {
509 switch (ch) {
510 case 'E':
511 fingerprint_hash = ssh_digest_alg_by_name(optarg);
512 if (fingerprint_hash == -1)
513 fatal("Invalid hash algorithm \"%s\"", optarg);
514 break;
515 case 'k':
516 key_only = 1;
517 break;
518 case 'l':
519 case 'L':
520 if (lflag != 0)
521 fatal("-%c flag already specified", lflag);
522 lflag = ch;
523 break;
524 case 'x':
525 case 'X':
526 if (xflag != 0)
527 fatal("-%c flag already specified", xflag);
528 xflag = ch;
529 break;
530 case 'c':
531 confirm = 1;
532 break;
533 case 'd':
534 deleting = 1;
535 break;
536 case 'D':
537 Dflag = 1;
538 break;
539 case 's':
540 pkcs11provider = optarg;
541 break;
542 case 'e':
543 deleting = 1;
544 pkcs11provider = optarg;
545 break;
546 case 't':
547 if ((lifetime = convtime(optarg)) == -1) {
548 fprintf(stderr, "Invalid lifetime\n");
549 ret = 1;
550 goto done;
551 }
552 break;
553 default:
554 usage();
555 ret = 1;
556 goto done;
557 }
558 }
559
560 if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1)
561 fatal("Invalid combination of actions");
562 else if (xflag) {
563 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1)
564 ret = 1;
565 goto done;
566 } else if (lflag) {
567 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1)
568 ret = 1;
569 goto done;
570 } else if (Dflag) {
571 if (delete_all(agent_fd) == -1)
572 ret = 1;
573 goto done;
574 }
575
576 argc -= optind;
577 argv += optind;
578 if (pkcs11provider != NULL) {
579 if (update_card(agent_fd, !deleting, pkcs11provider) == -1)
580 ret = 1;
581 goto done;
582 }
583 if (argc == 0) {
584 char buf[PATH_MAX];
585 struct passwd *pw;
586 struct stat st;
587 int count = 0;
588
589 if ((pw = getpwuid(getuid())) == NULL) {
590 fprintf(stderr, "No user found with uid %u\n",
591 (u_int)getuid());
592 ret = 1;
593 goto done;
594 }
595
596 for (i = 0; default_files[i]; i++) {
597 snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir,
598 default_files[i]);
599 if (stat(buf, &st) < 0)
600 continue;
601 if (do_file(agent_fd, deleting, key_only, buf) == -1)
602 ret = 1;
603 else
604 count++;
605 }
606 if (count == 0)
607 ret = 1;
608 } else {
609 for (i = 0; i < argc; i++) {
610 if (do_file(agent_fd, deleting, key_only,
611 argv[i]) == -1)
612 ret = 1;
613 }
614 }
615 clear_pass();
616
617 done:
618 ssh_close_authentication_socket(agent_fd);
619 return ret;
620 }
621