xref: /freebsd/crypto/openssh/ssh-add.c (revision 3f0164abf32b9b761e0a2cb4bdca3a8b84f156d4)
1 /* $OpenBSD: ssh-add.c,v 1.105 2012/12/05 15:42:52 markus 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 #include <sys/param.h>
43 
44 #include <openssl/evp.h>
45 #include "openbsd-compat/openssl-compat.h"
46 
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 
55 #include "xmalloc.h"
56 #include "ssh.h"
57 #include "rsa.h"
58 #include "log.h"
59 #include "key.h"
60 #include "buffer.h"
61 #include "authfd.h"
62 #include "authfile.h"
63 #include "pathnames.h"
64 #include "misc.h"
65 
66 /* argv0 */
67 extern char *__progname;
68 
69 /* Default files to add */
70 static char *default_files[] = {
71 	_PATH_SSH_CLIENT_ID_RSA,
72 	_PATH_SSH_CLIENT_ID_DSA,
73 #ifdef OPENSSL_HAS_ECC
74 	_PATH_SSH_CLIENT_ID_ECDSA,
75 #endif
76 	_PATH_SSH_CLIENT_IDENTITY,
77 	NULL
78 };
79 
80 /* Default lifetime (0 == forever) */
81 static int lifetime = 0;
82 
83 /* User has to confirm key use */
84 static int confirm = 0;
85 
86 /* we keep a cache of one passphrases */
87 static char *pass = NULL;
88 static void
89 clear_pass(void)
90 {
91 	if (pass) {
92 		memset(pass, 0, strlen(pass));
93 		xfree(pass);
94 		pass = NULL;
95 	}
96 }
97 
98 static int
99 delete_file(AuthenticationConnection *ac, const char *filename, int key_only)
100 {
101 	Key *public = NULL, *cert = NULL;
102 	char *certpath = NULL, *comment = NULL;
103 	int ret = -1;
104 
105 	public = key_load_public(filename, &comment);
106 	if (public == NULL) {
107 		printf("Bad key file %s\n", filename);
108 		return -1;
109 	}
110 	if (ssh_remove_identity(ac, public)) {
111 		fprintf(stderr, "Identity removed: %s (%s)\n", filename, comment);
112 		ret = 0;
113 	} else
114 		fprintf(stderr, "Could not remove identity: %s\n", filename);
115 
116 	if (key_only)
117 		goto out;
118 
119 	/* Now try to delete the corresponding certificate too */
120 	free(comment);
121 	comment = NULL;
122 	xasprintf(&certpath, "%s-cert.pub", filename);
123 	if ((cert = key_load_public(certpath, &comment)) == NULL)
124 		goto out;
125 	if (!key_equal_public(cert, public))
126 		fatal("Certificate %s does not match private key %s",
127 		    certpath, filename);
128 
129 	if (ssh_remove_identity(ac, cert)) {
130 		fprintf(stderr, "Identity removed: %s (%s)\n", certpath,
131 		    comment);
132 		ret = 0;
133 	} else
134 		fprintf(stderr, "Could not remove identity: %s\n", certpath);
135 
136  out:
137 	if (cert != NULL)
138 		key_free(cert);
139 	if (public != NULL)
140 		key_free(public);
141 	free(certpath);
142 	free(comment);
143 
144 	return ret;
145 }
146 
147 /* Send a request to remove all identities. */
148 static int
149 delete_all(AuthenticationConnection *ac)
150 {
151 	int ret = -1;
152 
153 	if (ssh_remove_all_identities(ac, 1))
154 		ret = 0;
155 	/* ignore error-code for ssh2 */
156 	ssh_remove_all_identities(ac, 2);
157 
158 	if (ret == 0)
159 		fprintf(stderr, "All identities removed.\n");
160 	else
161 		fprintf(stderr, "Failed to remove all identities.\n");
162 
163 	return ret;
164 }
165 
166 static int
167 add_file(AuthenticationConnection *ac, const char *filename, int key_only)
168 {
169 	Key *private, *cert;
170 	char *comment = NULL;
171 	char msg[1024], *certpath = NULL;
172 	int fd, perms_ok, ret = -1;
173 	Buffer keyblob;
174 
175 	if (strcmp(filename, "-") == 0) {
176 		fd = STDIN_FILENO;
177 		filename = "(stdin)";
178 	} else if ((fd = open(filename, O_RDONLY)) < 0) {
179 		perror(filename);
180 		return -1;
181 	}
182 
183 	/*
184 	 * Since we'll try to load a keyfile multiple times, permission errors
185 	 * will occur multiple times, so check perms first and bail if wrong.
186 	 */
187 	if (fd != STDIN_FILENO) {
188 		perms_ok = key_perm_ok(fd, filename);
189 		if (!perms_ok) {
190 			close(fd);
191 			return -1;
192 		}
193 	}
194 	buffer_init(&keyblob);
195 	if (!key_load_file(fd, filename, &keyblob)) {
196 		buffer_free(&keyblob);
197 		close(fd);
198 		return -1;
199 	}
200 	close(fd);
201 
202 	/* At first, try empty passphrase */
203 	private = key_parse_private(&keyblob, filename, "", &comment);
204 	if (comment == NULL)
205 		comment = xstrdup(filename);
206 	/* try last */
207 	if (private == NULL && pass != NULL)
208 		private = key_parse_private(&keyblob, filename, pass, NULL);
209 	if (private == NULL) {
210 		/* clear passphrase since it did not work */
211 		clear_pass();
212 		snprintf(msg, sizeof msg, "Enter passphrase for %.200s: ",
213 		    comment);
214 		for (;;) {
215 			pass = read_passphrase(msg, RP_ALLOW_STDIN);
216 			if (strcmp(pass, "") == 0) {
217 				clear_pass();
218 				xfree(comment);
219 				buffer_free(&keyblob);
220 				return -1;
221 			}
222 			private = key_parse_private(&keyblob, filename, pass,
223 			    &comment);
224 			if (private != NULL)
225 				break;
226 			clear_pass();
227 			snprintf(msg, sizeof msg,
228 			    "Bad passphrase, try again for %.200s: ", comment);
229 		}
230 	}
231 	buffer_free(&keyblob);
232 
233 	if (ssh_add_identity_constrained(ac, private, comment, lifetime,
234 	    confirm)) {
235 		fprintf(stderr, "Identity added: %s (%s)\n", filename, comment);
236 		ret = 0;
237 		if (lifetime != 0)
238 			fprintf(stderr,
239 			    "Lifetime set to %d seconds\n", lifetime);
240 		if (confirm != 0)
241 			fprintf(stderr,
242 			    "The user must confirm each use of the key\n");
243 	} else {
244 		fprintf(stderr, "Could not add identity: %s\n", filename);
245 	}
246 
247 	/* Skip trying to load the cert if requested */
248 	if (key_only)
249 		goto out;
250 
251 	/* Now try to add the certificate flavour too */
252 	xasprintf(&certpath, "%s-cert.pub", filename);
253 	if ((cert = key_load_public(certpath, NULL)) == NULL)
254 		goto out;
255 
256 	if (!key_equal_public(cert, private)) {
257 		error("Certificate %s does not match private key %s",
258 		    certpath, filename);
259 		key_free(cert);
260 		goto out;
261 	}
262 
263 	/* Graft with private bits */
264 	if (key_to_certified(private, key_cert_is_legacy(cert)) != 0) {
265 		error("%s: key_to_certified failed", __func__);
266 		key_free(cert);
267 		goto out;
268 	}
269 	key_cert_copy(cert, private);
270 	key_free(cert);
271 
272 	if (!ssh_add_identity_constrained(ac, private, comment,
273 	    lifetime, confirm)) {
274 		error("Certificate %s (%s) add failed", certpath,
275 		    private->cert->key_id);
276 	}
277 	fprintf(stderr, "Certificate added: %s (%s)\n", certpath,
278 	    private->cert->key_id);
279 	if (lifetime != 0)
280 		fprintf(stderr, "Lifetime set to %d seconds\n", lifetime);
281 	if (confirm != 0)
282 		fprintf(stderr, "The user must confirm each use of the key\n");
283  out:
284 	if (certpath != NULL)
285 		xfree(certpath);
286 	xfree(comment);
287 	key_free(private);
288 
289 	return ret;
290 }
291 
292 static int
293 update_card(AuthenticationConnection *ac, int add, const char *id)
294 {
295 	char *pin;
296 	int ret = -1;
297 
298 	pin = read_passphrase("Enter passphrase for PKCS#11: ", RP_ALLOW_STDIN);
299 	if (pin == NULL)
300 		return -1;
301 
302 	if (ssh_update_card(ac, add, id, pin, lifetime, confirm)) {
303 		fprintf(stderr, "Card %s: %s\n",
304 		    add ? "added" : "removed", id);
305 		ret = 0;
306 	} else {
307 		fprintf(stderr, "Could not %s card: %s\n",
308 		    add ? "add" : "remove", id);
309 		ret = -1;
310 	}
311 	xfree(pin);
312 	return ret;
313 }
314 
315 static int
316 list_identities(AuthenticationConnection *ac, int do_fp)
317 {
318 	Key *key;
319 	char *comment, *fp;
320 	int had_identities = 0;
321 	int version;
322 
323 	for (version = 1; version <= 2; version++) {
324 		for (key = ssh_get_first_identity(ac, &comment, version);
325 		    key != NULL;
326 		    key = ssh_get_next_identity(ac, &comment, version)) {
327 			had_identities = 1;
328 			if (do_fp) {
329 				fp = key_fingerprint(key, SSH_FP_MD5,
330 				    SSH_FP_HEX);
331 				printf("%d %s %s (%s)\n",
332 				    key_size(key), fp, comment, key_type(key));
333 				xfree(fp);
334 			} else {
335 				if (!key_write(key, stdout))
336 					fprintf(stderr, "key_write failed");
337 				fprintf(stdout, " %s\n", comment);
338 			}
339 			key_free(key);
340 			xfree(comment);
341 		}
342 	}
343 	if (!had_identities) {
344 		printf("The agent has no identities.\n");
345 		return -1;
346 	}
347 	return 0;
348 }
349 
350 static int
351 lock_agent(AuthenticationConnection *ac, int lock)
352 {
353 	char prompt[100], *p1, *p2;
354 	int passok = 1, ret = -1;
355 
356 	strlcpy(prompt, "Enter lock password: ", sizeof(prompt));
357 	p1 = read_passphrase(prompt, RP_ALLOW_STDIN);
358 	if (lock) {
359 		strlcpy(prompt, "Again: ", sizeof prompt);
360 		p2 = read_passphrase(prompt, RP_ALLOW_STDIN);
361 		if (strcmp(p1, p2) != 0) {
362 			fprintf(stderr, "Passwords do not match.\n");
363 			passok = 0;
364 		}
365 		memset(p2, 0, strlen(p2));
366 		xfree(p2);
367 	}
368 	if (passok && ssh_lock_agent(ac, lock, p1)) {
369 		fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un");
370 		ret = 0;
371 	} else
372 		fprintf(stderr, "Failed to %slock agent.\n", lock ? "" : "un");
373 	memset(p1, 0, strlen(p1));
374 	xfree(p1);
375 	return (ret);
376 }
377 
378 static int
379 do_file(AuthenticationConnection *ac, int deleting, int key_only, char *file)
380 {
381 	if (deleting) {
382 		if (delete_file(ac, file, key_only) == -1)
383 			return -1;
384 	} else {
385 		if (add_file(ac, file, key_only) == -1)
386 			return -1;
387 	}
388 	return 0;
389 }
390 
391 static void
392 usage(void)
393 {
394 	fprintf(stderr, "usage: %s [options] [file ...]\n", __progname);
395 	fprintf(stderr, "Options:\n");
396 	fprintf(stderr, "  -l          List fingerprints of all identities.\n");
397 	fprintf(stderr, "  -L          List public key parameters of all identities.\n");
398 	fprintf(stderr, "  -k          Load only keys and not certificates.\n");
399 	fprintf(stderr, "  -c          Require confirmation to sign using identities\n");
400 	fprintf(stderr, "  -t life     Set lifetime (in seconds) when adding identities.\n");
401 	fprintf(stderr, "  -d          Delete identity.\n");
402 	fprintf(stderr, "  -D          Delete all identities.\n");
403 	fprintf(stderr, "  -x          Lock agent.\n");
404 	fprintf(stderr, "  -X          Unlock agent.\n");
405 	fprintf(stderr, "  -s pkcs11   Add keys from PKCS#11 provider.\n");
406 	fprintf(stderr, "  -e pkcs11   Remove keys provided by PKCS#11 provider.\n");
407 }
408 
409 int
410 main(int argc, char **argv)
411 {
412 	extern char *optarg;
413 	extern int optind;
414 	AuthenticationConnection *ac = NULL;
415 	char *pkcs11provider = NULL;
416 	int i, ch, deleting = 0, ret = 0, key_only = 0;
417 
418 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
419 	sanitise_stdfd();
420 
421 	__progname = ssh_get_progname(argv[0]);
422 	seed_rng();
423 
424 	OpenSSL_add_all_algorithms();
425 
426 	/* At first, get a connection to the authentication agent. */
427 	ac = ssh_get_authentication_connection();
428 	if (ac == NULL) {
429 		fprintf(stderr,
430 		    "Could not open a connection to your authentication agent.\n");
431 		exit(2);
432 	}
433 	while ((ch = getopt(argc, argv, "klLcdDxXe:s:t:")) != -1) {
434 		switch (ch) {
435 		case 'k':
436 			key_only = 1;
437 			break;
438 		case 'l':
439 		case 'L':
440 			if (list_identities(ac, ch == 'l' ? 1 : 0) == -1)
441 				ret = 1;
442 			goto done;
443 		case 'x':
444 		case 'X':
445 			if (lock_agent(ac, ch == 'x' ? 1 : 0) == -1)
446 				ret = 1;
447 			goto done;
448 		case 'c':
449 			confirm = 1;
450 			break;
451 		case 'd':
452 			deleting = 1;
453 			break;
454 		case 'D':
455 			if (delete_all(ac) == -1)
456 				ret = 1;
457 			goto done;
458 		case 's':
459 			pkcs11provider = optarg;
460 			break;
461 		case 'e':
462 			deleting = 1;
463 			pkcs11provider = optarg;
464 			break;
465 		case 't':
466 			if ((lifetime = convtime(optarg)) == -1) {
467 				fprintf(stderr, "Invalid lifetime\n");
468 				ret = 1;
469 				goto done;
470 			}
471 			break;
472 		default:
473 			usage();
474 			ret = 1;
475 			goto done;
476 		}
477 	}
478 	argc -= optind;
479 	argv += optind;
480 	if (pkcs11provider != NULL) {
481 		if (update_card(ac, !deleting, pkcs11provider) == -1)
482 			ret = 1;
483 		goto done;
484 	}
485 	if (argc == 0) {
486 		char buf[MAXPATHLEN];
487 		struct passwd *pw;
488 		struct stat st;
489 		int count = 0;
490 
491 		if ((pw = getpwuid(getuid())) == NULL) {
492 			fprintf(stderr, "No user found with uid %u\n",
493 			    (u_int)getuid());
494 			ret = 1;
495 			goto done;
496 		}
497 
498 		for (i = 0; default_files[i]; i++) {
499 			snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir,
500 			    default_files[i]);
501 			if (stat(buf, &st) < 0)
502 				continue;
503 			if (do_file(ac, deleting, key_only, buf) == -1)
504 				ret = 1;
505 			else
506 				count++;
507 		}
508 		if (count == 0)
509 			ret = 1;
510 	} else {
511 		for (i = 0; i < argc; i++) {
512 			if (do_file(ac, deleting, key_only, argv[i]) == -1)
513 				ret = 1;
514 		}
515 	}
516 	clear_pass();
517 
518 done:
519 	ssh_close_authentication_connection(ac);
520 	return ret;
521 }
522