xref: /freebsd/crypto/openssh/ssh-add.c (revision 55141f2c8991b2a6adbf30bb0fe3e6cbc303f06d)
1 /* $OpenBSD: ssh-add.c,v 1.168 2023/07/06 22:17:59 dtucker 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 #ifdef WITH_OPENSSL
44 # include <openssl/evp.h>
45 # include "openbsd-compat/openssl-compat.h"
46 #endif
47 
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <pwd.h>
51 #include <stdarg.h>
52 #include <stdio.h>
53 #include <stdlib.h>
54 #include <string.h>
55 #include <unistd.h>
56 #include <limits.h>
57 
58 #include "xmalloc.h"
59 #include "ssh.h"
60 #include "log.h"
61 #include "sshkey.h"
62 #include "sshbuf.h"
63 #include "authfd.h"
64 #include "authfile.h"
65 #include "pathnames.h"
66 #include "misc.h"
67 #include "ssherr.h"
68 #include "digest.h"
69 #include "ssh-sk.h"
70 #include "sk-api.h"
71 #include "hostfile.h"
72 
73 /* argv0 */
74 extern char *__progname;
75 
76 /* Default files to add */
77 static char *default_files[] = {
78 #ifdef WITH_OPENSSL
79 	_PATH_SSH_CLIENT_ID_RSA,
80 #ifdef OPENSSL_HAS_ECC
81 	_PATH_SSH_CLIENT_ID_ECDSA,
82 	_PATH_SSH_CLIENT_ID_ECDSA_SK,
83 #endif
84 #endif /* WITH_OPENSSL */
85 	_PATH_SSH_CLIENT_ID_ED25519,
86 	_PATH_SSH_CLIENT_ID_ED25519_SK,
87 	_PATH_SSH_CLIENT_ID_XMSS,
88 	_PATH_SSH_CLIENT_ID_DSA,
89 	NULL
90 };
91 
92 static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
93 
94 /* Default lifetime (0 == forever) */
95 static int lifetime = 0;
96 
97 /* User has to confirm key use */
98 static int confirm = 0;
99 
100 /* Maximum number of signatures (XMSS) */
101 static u_int maxsign = 0;
102 static u_int minleft = 0;
103 
104 /* we keep a cache of one passphrase */
105 static char *pass = NULL;
106 static void
107 clear_pass(void)
108 {
109 	if (pass) {
110 		freezero(pass, strlen(pass));
111 		pass = NULL;
112 	}
113 }
114 
115 static int
116 delete_one(int agent_fd, const struct sshkey *key, const char *comment,
117     const char *path, int qflag)
118 {
119 	int r;
120 
121 	if ((r = ssh_remove_identity(agent_fd, key)) != 0) {
122 		fprintf(stderr, "Could not remove identity \"%s\": %s\n",
123 		    path, ssh_err(r));
124 		return r;
125 	}
126 	if (!qflag) {
127 		fprintf(stderr, "Identity removed: %s %s (%s)\n", path,
128 		    sshkey_type(key), comment ? comment : "no comment");
129 	}
130 	return 0;
131 }
132 
133 static int
134 delete_stdin(int agent_fd, int qflag)
135 {
136 	char *line = NULL, *cp;
137 	size_t linesize = 0;
138 	struct sshkey *key = NULL;
139 	int lnum = 0, r, ret = -1;
140 
141 	while (getline(&line, &linesize, stdin) != -1) {
142 		lnum++;
143 		sshkey_free(key);
144 		key = NULL;
145 		line[strcspn(line, "\n")] = '\0';
146 		cp = line + strspn(line, " \t");
147 		if (*cp == '#' || *cp == '\0')
148 			continue;
149 		if ((key = sshkey_new(KEY_UNSPEC)) == NULL)
150 			fatal_f("sshkey_new");
151 		if ((r = sshkey_read(key, &cp)) != 0) {
152 			error_r(r, "(stdin):%d: invalid key", lnum);
153 			continue;
154 		}
155 		if (delete_one(agent_fd, key, cp, "(stdin)", qflag) == 0)
156 			ret = 0;
157 	}
158 	sshkey_free(key);
159 	free(line);
160 	return ret;
161 }
162 
163 static int
164 delete_file(int agent_fd, const char *filename, int key_only, int qflag)
165 {
166 	struct sshkey *public, *cert = NULL;
167 	char *certpath = NULL, *comment = NULL;
168 	int r, ret = -1;
169 
170 	if (strcmp(filename, "-") == 0)
171 		return delete_stdin(agent_fd, qflag);
172 
173 	if ((r = sshkey_load_public(filename, &public,  &comment)) != 0) {
174 		printf("Bad key file %s: %s\n", filename, ssh_err(r));
175 		return -1;
176 	}
177 	if (delete_one(agent_fd, public, comment, filename, qflag) == 0)
178 		ret = 0;
179 
180 	if (key_only)
181 		goto out;
182 
183 	/* Now try to delete the corresponding certificate too */
184 	free(comment);
185 	comment = NULL;
186 	xasprintf(&certpath, "%s-cert.pub", filename);
187 	if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) {
188 		if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
189 			error_r(r, "Failed to load certificate \"%s\"", certpath);
190 		goto out;
191 	}
192 
193 	if (!sshkey_equal_public(cert, public))
194 		fatal("Certificate %s does not match private key %s",
195 		    certpath, filename);
196 
197 	if (delete_one(agent_fd, cert, comment, certpath, qflag) == 0)
198 		ret = 0;
199 
200  out:
201 	sshkey_free(cert);
202 	sshkey_free(public);
203 	free(certpath);
204 	free(comment);
205 
206 	return ret;
207 }
208 
209 /* Send a request to remove all identities. */
210 static int
211 delete_all(int agent_fd, int qflag)
212 {
213 	int ret = -1;
214 
215 	/*
216 	 * Since the agent might be forwarded, old or non-OpenSSH, when asked
217 	 * to remove all keys, attempt to remove both protocol v.1 and v.2
218 	 * keys.
219 	 */
220 	if (ssh_remove_all_identities(agent_fd, 2) == 0)
221 		ret = 0;
222 	/* ignore error-code for ssh1 */
223 	ssh_remove_all_identities(agent_fd, 1);
224 
225 	if (ret != 0)
226 		fprintf(stderr, "Failed to remove all identities.\n");
227 	else if (!qflag)
228 		fprintf(stderr, "All identities removed.\n");
229 
230 	return ret;
231 }
232 
233 static int
234 add_file(int agent_fd, const char *filename, int key_only, int qflag,
235     const char *skprovider, struct dest_constraint **dest_constraints,
236     size_t ndest_constraints)
237 {
238 	struct sshkey *private, *cert;
239 	char *comment = NULL;
240 	char msg[1024], *certpath = NULL;
241 	int r, fd, ret = -1;
242 	size_t i;
243 	u_int32_t left;
244 	struct sshbuf *keyblob;
245 	struct ssh_identitylist *idlist;
246 
247 	if (strcmp(filename, "-") == 0) {
248 		fd = STDIN_FILENO;
249 		filename = "(stdin)";
250 	} else if ((fd = open(filename, O_RDONLY)) == -1) {
251 		perror(filename);
252 		return -1;
253 	}
254 
255 	/*
256 	 * Since we'll try to load a keyfile multiple times, permission errors
257 	 * will occur multiple times, so check perms first and bail if wrong.
258 	 */
259 	if (fd != STDIN_FILENO) {
260 		if (sshkey_perm_ok(fd, filename) != 0) {
261 			close(fd);
262 			return -1;
263 		}
264 	}
265 	if ((r = sshbuf_load_fd(fd, &keyblob)) != 0) {
266 		fprintf(stderr, "Error loading key \"%s\": %s\n",
267 		    filename, ssh_err(r));
268 		sshbuf_free(keyblob);
269 		close(fd);
270 		return -1;
271 	}
272 	close(fd);
273 
274 	/* At first, try empty passphrase */
275 	if ((r = sshkey_parse_private_fileblob(keyblob, "", &private,
276 	    &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
277 		fprintf(stderr, "Error loading key \"%s\": %s\n",
278 		    filename, ssh_err(r));
279 		goto fail_load;
280 	}
281 	/* try last */
282 	if (private == NULL && pass != NULL) {
283 		if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private,
284 		    &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
285 			fprintf(stderr, "Error loading key \"%s\": %s\n",
286 			    filename, ssh_err(r));
287 			goto fail_load;
288 		}
289 	}
290 	if (private == NULL) {
291 		/* clear passphrase since it did not work */
292 		clear_pass();
293 		snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ",
294 		    filename, confirm ? " (will confirm each use)" : "");
295 		for (;;) {
296 			pass = read_passphrase(msg, RP_ALLOW_STDIN);
297 			if (strcmp(pass, "") == 0)
298 				goto fail_load;
299 			if ((r = sshkey_parse_private_fileblob(keyblob, pass,
300 			    &private, &comment)) == 0)
301 				break;
302 			else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
303 				fprintf(stderr,
304 				    "Error loading key \"%s\": %s\n",
305 				    filename, ssh_err(r));
306  fail_load:
307 				clear_pass();
308 				sshbuf_free(keyblob);
309 				return -1;
310 			}
311 			clear_pass();
312 			snprintf(msg, sizeof msg,
313 			    "Bad passphrase, try again for %s%s: ", filename,
314 			    confirm ? " (will confirm each use)" : "");
315 		}
316 	}
317 	if (comment == NULL || *comment == '\0')
318 		comment = xstrdup(filename);
319 	sshbuf_free(keyblob);
320 
321 	/* For XMSS */
322 	if ((r = sshkey_set_filename(private, filename)) != 0) {
323 		fprintf(stderr, "Could not add filename to private key: %s (%s)\n",
324 		    filename, comment);
325 		goto out;
326 	}
327 	if (maxsign && minleft &&
328 	    (r = ssh_fetch_identitylist(agent_fd, &idlist)) == 0) {
329 		for (i = 0; i < idlist->nkeys; i++) {
330 			if (!sshkey_equal_public(idlist->keys[i], private))
331 				continue;
332 			left = sshkey_signatures_left(idlist->keys[i]);
333 			if (left < minleft) {
334 				fprintf(stderr,
335 				    "Only %d signatures left.\n", left);
336 				break;
337 			}
338 			fprintf(stderr, "Skipping update: ");
339 			if (left == minleft) {
340 				fprintf(stderr,
341 				    "required signatures left (%d).\n", left);
342 			} else {
343 				fprintf(stderr,
344 				    "more signatures left (%d) than"
345 				    " required (%d).\n", left, minleft);
346 			}
347 			ssh_free_identitylist(idlist);
348 			goto out;
349 		}
350 		ssh_free_identitylist(idlist);
351 	}
352 
353 	if (sshkey_is_sk(private)) {
354 		if (skprovider == NULL) {
355 			fprintf(stderr, "Cannot load FIDO key %s "
356 			    "without provider\n", filename);
357 			goto out;
358 		}
359 	} else {
360 		/* Don't send provider constraint for other keys */
361 		skprovider = NULL;
362 	}
363 
364 	if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
365 	    lifetime, confirm, maxsign, skprovider,
366 	    dest_constraints, ndest_constraints)) == 0) {
367 		ret = 0;
368 		if (!qflag) {
369 			fprintf(stderr, "Identity added: %s (%s)\n",
370 			    filename, comment);
371 			if (lifetime != 0) {
372 				fprintf(stderr,
373 				    "Lifetime set to %d seconds\n", lifetime);
374 			}
375 			if (confirm != 0) {
376 				fprintf(stderr, "The user must confirm "
377 				    "each use of the key\n");
378 			}
379 		}
380 	} else {
381 		fprintf(stderr, "Could not add identity \"%s\": %s\n",
382 		    filename, ssh_err(r));
383 	}
384 
385 	/* Skip trying to load the cert if requested */
386 	if (key_only)
387 		goto out;
388 
389 	/* Now try to add the certificate flavour too */
390 	xasprintf(&certpath, "%s-cert.pub", filename);
391 	if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) {
392 		if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
393 			error_r(r, "Failed to load certificate \"%s\"", certpath);
394 		goto out;
395 	}
396 
397 	if (!sshkey_equal_public(cert, private)) {
398 		error("Certificate %s does not match private key %s",
399 		    certpath, filename);
400 		sshkey_free(cert);
401 		goto out;
402 	}
403 
404 	/* Graft with private bits */
405 	if ((r = sshkey_to_certified(private)) != 0) {
406 		error_fr(r, "sshkey_to_certified");
407 		sshkey_free(cert);
408 		goto out;
409 	}
410 	if ((r = sshkey_cert_copy(cert, private)) != 0) {
411 		error_fr(r, "sshkey_cert_copy");
412 		sshkey_free(cert);
413 		goto out;
414 	}
415 	sshkey_free(cert);
416 
417 	if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
418 	    lifetime, confirm, maxsign, skprovider,
419 	    dest_constraints, ndest_constraints)) != 0) {
420 		error_r(r, "Certificate %s (%s) add failed", certpath,
421 		    private->cert->key_id);
422 		goto out;
423 	}
424 	/* success */
425 	if (!qflag) {
426 		fprintf(stderr, "Certificate added: %s (%s)\n", certpath,
427 		    private->cert->key_id);
428 		if (lifetime != 0) {
429 			fprintf(stderr, "Lifetime set to %d seconds\n",
430 			    lifetime);
431 		}
432 		if (confirm != 0) {
433 			fprintf(stderr, "The user must confirm each use "
434 			    "of the key\n");
435 		}
436 	}
437 
438  out:
439 	free(certpath);
440 	free(comment);
441 	sshkey_free(private);
442 
443 	return ret;
444 }
445 
446 static int
447 update_card(int agent_fd, int add, const char *id, int qflag,
448     struct dest_constraint **dest_constraints, size_t ndest_constraints)
449 {
450 	char *pin = NULL;
451 	int r, ret = -1;
452 
453 	if (add) {
454 		if ((pin = read_passphrase("Enter passphrase for PKCS#11: ",
455 		    RP_ALLOW_STDIN)) == NULL)
456 			return -1;
457 	}
458 
459 	if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin,
460 	    lifetime, confirm, dest_constraints, ndest_constraints)) == 0) {
461 		ret = 0;
462 		if (!qflag) {
463 			fprintf(stderr, "Card %s: %s\n",
464 			    add ? "added" : "removed", id);
465 		}
466 	} else {
467 		fprintf(stderr, "Could not %s card \"%s\": %s\n",
468 		    add ? "add" : "remove", id, ssh_err(r));
469 		ret = -1;
470 	}
471 	free(pin);
472 	return ret;
473 }
474 
475 static int
476 test_key(int agent_fd, const char *filename)
477 {
478 	struct sshkey *key = NULL;
479 	u_char *sig = NULL;
480 	const char *alg = NULL;
481 	size_t slen = 0;
482 	int r, ret = -1;
483 	char data[1024];
484 
485 	if ((r = sshkey_load_public(filename, &key, NULL)) != 0) {
486 		error_r(r, "Couldn't read public key %s", filename);
487 		return -1;
488 	}
489 	if (sshkey_type_plain(key->type) == KEY_RSA)
490 		alg = "rsa-sha2-256";
491 	arc4random_buf(data, sizeof(data));
492 	if ((r = ssh_agent_sign(agent_fd, key, &sig, &slen, data, sizeof(data),
493 	    alg, 0)) != 0) {
494 		error_r(r, "Agent signature failed for %s", filename);
495 		goto done;
496 	}
497 	if ((r = sshkey_verify(key, sig, slen, data, sizeof(data),
498 	    alg, 0, NULL)) != 0) {
499 		error_r(r, "Signature verification failed for %s", filename);
500 		goto done;
501 	}
502 	/* success */
503 	ret = 0;
504  done:
505 	free(sig);
506 	sshkey_free(key);
507 	return ret;
508 }
509 
510 static int
511 list_identities(int agent_fd, int do_fp)
512 {
513 	char *fp;
514 	int r;
515 	struct ssh_identitylist *idlist;
516 	u_int32_t left;
517 	size_t i;
518 
519 	if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) {
520 		if (r != SSH_ERR_AGENT_NO_IDENTITIES)
521 			fprintf(stderr, "error fetching identities: %s\n",
522 			    ssh_err(r));
523 		else
524 			printf("The agent has no identities.\n");
525 		return -1;
526 	}
527 	for (i = 0; i < idlist->nkeys; i++) {
528 		if (do_fp) {
529 			fp = sshkey_fingerprint(idlist->keys[i],
530 			    fingerprint_hash, SSH_FP_DEFAULT);
531 			printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]),
532 			    fp == NULL ? "(null)" : fp, idlist->comments[i],
533 			    sshkey_type(idlist->keys[i]));
534 			free(fp);
535 		} else {
536 			if ((r = sshkey_write(idlist->keys[i], stdout)) != 0) {
537 				fprintf(stderr, "sshkey_write: %s\n",
538 				    ssh_err(r));
539 				continue;
540 			}
541 			fprintf(stdout, " %s", idlist->comments[i]);
542 			left = sshkey_signatures_left(idlist->keys[i]);
543 			if (left > 0)
544 				fprintf(stdout,
545 				    " [signatures left %d]", left);
546 			fprintf(stdout, "\n");
547 		}
548 	}
549 	ssh_free_identitylist(idlist);
550 	return 0;
551 }
552 
553 static int
554 lock_agent(int agent_fd, int lock)
555 {
556 	char prompt[100], *p1, *p2;
557 	int r, passok = 1, ret = -1;
558 
559 	strlcpy(prompt, "Enter lock password: ", sizeof(prompt));
560 	p1 = read_passphrase(prompt, RP_ALLOW_STDIN);
561 	if (lock) {
562 		strlcpy(prompt, "Again: ", sizeof prompt);
563 		p2 = read_passphrase(prompt, RP_ALLOW_STDIN);
564 		if (strcmp(p1, p2) != 0) {
565 			fprintf(stderr, "Passwords do not match.\n");
566 			passok = 0;
567 		}
568 		freezero(p2, strlen(p2));
569 	}
570 	if (passok) {
571 		if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) {
572 			fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un");
573 			ret = 0;
574 		} else {
575 			fprintf(stderr, "Failed to %slock agent: %s\n",
576 			    lock ? "" : "un", ssh_err(r));
577 		}
578 	}
579 	freezero(p1, strlen(p1));
580 	return (ret);
581 }
582 
583 static int
584 load_resident_keys(int agent_fd, const char *skprovider, int qflag,
585     struct dest_constraint **dest_constraints, size_t ndest_constraints)
586 {
587 	struct sshsk_resident_key **srks;
588 	size_t nsrks, i;
589 	struct sshkey *key;
590 	int r, ok = 0;
591 	char *fp;
592 
593 	pass = read_passphrase("Enter PIN for authenticator: ", RP_ALLOW_STDIN);
594 	if ((r = sshsk_load_resident(skprovider, NULL, pass, 0,
595 	    &srks, &nsrks)) != 0) {
596 		error_r(r, "Unable to load resident keys");
597 		return r;
598 	}
599 	for (i = 0; i < nsrks; i++) {
600 		key = srks[i]->key;
601 		if ((fp = sshkey_fingerprint(key,
602 		    fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
603 			fatal_f("sshkey_fingerprint failed");
604 		if ((r = ssh_add_identity_constrained(agent_fd, key, "",
605 		    lifetime, confirm, maxsign, skprovider,
606 		    dest_constraints, ndest_constraints)) != 0) {
607 			error("Unable to add key %s %s",
608 			    sshkey_type(key), fp);
609 			free(fp);
610 			ok = r;
611 			continue;
612 		}
613 		if (ok == 0)
614 			ok = 1;
615 		if (!qflag) {
616 			fprintf(stderr, "Resident identity added: %s %s\n",
617 			    sshkey_type(key), fp);
618 			if (lifetime != 0) {
619 				fprintf(stderr,
620 				    "Lifetime set to %d seconds\n", lifetime);
621 			}
622 			if (confirm != 0) {
623 				fprintf(stderr, "The user must confirm "
624 				    "each use of the key\n");
625 			}
626 		}
627 		free(fp);
628 	}
629 	sshsk_free_resident_keys(srks, nsrks);
630 	if (nsrks == 0)
631 		return SSH_ERR_KEY_NOT_FOUND;
632 	return ok == 1 ? 0 : ok;
633 }
634 
635 static int
636 do_file(int agent_fd, int deleting, int key_only, char *file, int qflag,
637     const char *skprovider, struct dest_constraint **dest_constraints,
638     size_t ndest_constraints)
639 {
640 	if (deleting) {
641 		if (delete_file(agent_fd, file, key_only, qflag) == -1)
642 			return -1;
643 	} else {
644 		if (add_file(agent_fd, file, key_only, qflag, skprovider,
645 		    dest_constraints, ndest_constraints) == -1)
646 			return -1;
647 	}
648 	return 0;
649 }
650 
651 /* Append string 's' to a NULL-terminated array of strings */
652 static void
653 stringlist_append(char ***listp, const char *s)
654 {
655 	size_t i = 0;
656 
657 	if (*listp == NULL)
658 		*listp = xcalloc(2, sizeof(**listp));
659 	else {
660 		for (i = 0; (*listp)[i] != NULL; i++)
661 			; /* count */
662 		*listp = xrecallocarray(*listp, i + 1, i + 2, sizeof(**listp));
663 	}
664 	(*listp)[i] = xstrdup(s);
665 }
666 
667 static void
668 parse_dest_constraint_hop(const char *s, struct dest_constraint_hop *dch,
669     char **hostkey_files)
670 {
671 	char *user = NULL, *host, *os, *path;
672 	size_t i;
673 	struct hostkeys *hostkeys;
674 	const struct hostkey_entry *hke;
675 	int r, want_ca;
676 
677 	memset(dch, '\0', sizeof(*dch));
678 	os = xstrdup(s);
679 	if ((host = strchr(os, '@')) == NULL)
680 		host = os;
681 	else {
682 		*host++ = '\0';
683 		user = os;
684 	}
685 	cleanhostname(host);
686 	/* Trivial case: username@ (all hosts) */
687 	if (*host == '\0') {
688 		if (user == NULL) {
689 			fatal("Invalid key destination constraint \"%s\": "
690 			    "does not specify user or host", s);
691 		}
692 		dch->user = xstrdup(user);
693 		/* other fields left blank */
694 		free(os);
695 		return;
696 	}
697 	if (hostkey_files == NULL)
698 		fatal_f("no hostkey files");
699 	/* Otherwise we need to look up the keys for this hostname */
700 	hostkeys = init_hostkeys();
701 	for (i = 0; hostkey_files[i]; i++) {
702 		path = tilde_expand_filename(hostkey_files[i], getuid());
703 		debug2_f("looking up host keys for \"%s\" in %s", host, path);
704                 load_hostkeys(hostkeys, host, path, 0);
705 		free(path);
706 	}
707 	dch->user = user == NULL ? NULL : xstrdup(user);
708 	dch->hostname = xstrdup(host);
709 	for (i = 0; i < hostkeys->num_entries; i++) {
710 		hke = hostkeys->entries + i;
711 		want_ca = hke->marker == MRK_CA;
712 		if (hke->marker != MRK_NONE && !want_ca)
713 			continue;
714 		debug3_f("%s%s%s: adding %s %skey from %s:%lu as key %u",
715 		    user == NULL ? "": user, user == NULL ? "" : "@",
716 		    host, sshkey_type(hke->key), want_ca ? "CA " : "",
717 		    hke->file, hke->line, dch->nkeys);
718 		dch->keys = xrecallocarray(dch->keys, dch->nkeys,
719 		    dch->nkeys + 1, sizeof(*dch->keys));
720 		dch->key_is_ca = xrecallocarray(dch->key_is_ca, dch->nkeys,
721 		    dch->nkeys + 1, sizeof(*dch->key_is_ca));
722 		if ((r = sshkey_from_private(hke->key,
723 		    &(dch->keys[dch->nkeys]))) != 0)
724 			fatal_fr(r, "sshkey_from_private");
725 		dch->key_is_ca[dch->nkeys] = want_ca;
726 		dch->nkeys++;
727 	}
728 	if (dch->nkeys == 0)
729 		fatal("No host keys found for destination \"%s\"", host);
730 	free_hostkeys(hostkeys);
731 	free(os);
732 	return;
733 }
734 
735 static void
736 parse_dest_constraint(const char *s, struct dest_constraint ***dcp,
737     size_t *ndcp, char **hostkey_files)
738 {
739 	struct dest_constraint *dc;
740 	char *os, *cp;
741 
742 	dc = xcalloc(1, sizeof(*dc));
743 	os = xstrdup(s);
744 	if ((cp = strchr(os, '>')) == NULL) {
745 		/* initial hop; no 'from' hop specified */
746 		parse_dest_constraint_hop(os, &dc->to, hostkey_files);
747 	} else {
748 		/* two hops specified */
749 		*(cp++) = '\0';
750 		parse_dest_constraint_hop(os, &dc->from, hostkey_files);
751 		parse_dest_constraint_hop(cp, &dc->to, hostkey_files);
752 		if (dc->from.user != NULL) {
753 			fatal("Invalid key constraint %s: cannot specify "
754 			    "user on 'from' host", os);
755 		}
756 	}
757 	/* XXX eliminate or error on duplicates */
758 	debug2_f("constraint %zu: %s%s%s (%u keys) > %s%s%s (%u keys)", *ndcp,
759 	    dc->from.user ? dc->from.user : "", dc->from.user ? "@" : "",
760 	    dc->from.hostname ? dc->from.hostname : "(ORIGIN)", dc->from.nkeys,
761 	    dc->to.user ? dc->to.user : "", dc->to.user ? "@" : "",
762 	    dc->to.hostname ? dc->to.hostname : "(ANY)", dc->to.nkeys);
763 	*dcp = xrecallocarray(*dcp, *ndcp, *ndcp + 1, sizeof(**dcp));
764 	(*dcp)[(*ndcp)++] = dc;
765 	free(os);
766 }
767 
768 
769 static void
770 usage(void)
771 {
772 	fprintf(stderr,
773 "usage: ssh-add [-cDdKkLlqvXx] [-E fingerprint_hash] [-H hostkey_file]\n"
774 "               [-h destination_constraint] [-S provider] [-t life]\n"
775 #ifdef WITH_XMSS
776 "               [-M maxsign] [-m minleft]\n"
777 #endif
778 "               [file ...]\n"
779 "       ssh-add -s pkcs11\n"
780 "       ssh-add -e pkcs11\n"
781 "       ssh-add -T pubkey ...\n"
782 	);
783 }
784 
785 int
786 main(int argc, char **argv)
787 {
788 	extern char *optarg;
789 	extern int optind;
790 	int agent_fd;
791 	char *pkcs11provider = NULL, *skprovider = NULL;
792 	char **dest_constraint_strings = NULL, **hostkey_files = NULL;
793 	int r, i, ch, deleting = 0, ret = 0, key_only = 0, do_download = 0;
794 	int xflag = 0, lflag = 0, Dflag = 0, qflag = 0, Tflag = 0;
795 	SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
796 	LogLevel log_level = SYSLOG_LEVEL_INFO;
797 	struct dest_constraint **dest_constraints = NULL;
798 	size_t ndest_constraints = 0;
799 
800 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
801 	sanitise_stdfd();
802 
803 	__progname = ssh_get_progname(argv[0]);
804 	seed_rng();
805 
806 	log_init(__progname, log_level, log_facility, 1);
807 
808 	setvbuf(stdout, NULL, _IOLBF, 0);
809 
810 	/* First, get a connection to the authentication agent. */
811 	switch (r = ssh_get_authentication_socket(&agent_fd)) {
812 	case 0:
813 		break;
814 	case SSH_ERR_AGENT_NOT_PRESENT:
815 		fprintf(stderr, "Could not open a connection to your "
816 		    "authentication agent.\n");
817 		exit(2);
818 	default:
819 		fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r));
820 		exit(2);
821 	}
822 
823 	skprovider = getenv("SSH_SK_PROVIDER");
824 
825 	while ((ch = getopt(argc, argv, "vkKlLcdDTxXE:e:h:H:M:m:qs:S:t:")) != -1) {
826 		switch (ch) {
827 		case 'v':
828 			if (log_level == SYSLOG_LEVEL_INFO)
829 				log_level = SYSLOG_LEVEL_DEBUG1;
830 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
831 				log_level++;
832 			break;
833 		case 'E':
834 			fingerprint_hash = ssh_digest_alg_by_name(optarg);
835 			if (fingerprint_hash == -1)
836 				fatal("Invalid hash algorithm \"%s\"", optarg);
837 			break;
838 		case 'H':
839 			stringlist_append(&hostkey_files, optarg);
840 			break;
841 		case 'h':
842 			stringlist_append(&dest_constraint_strings, optarg);
843 			break;
844 		case 'k':
845 			key_only = 1;
846 			break;
847 		case 'K':
848 			do_download = 1;
849 			break;
850 		case 'l':
851 		case 'L':
852 			if (lflag != 0)
853 				fatal("-%c flag already specified", lflag);
854 			lflag = ch;
855 			break;
856 		case 'x':
857 		case 'X':
858 			if (xflag != 0)
859 				fatal("-%c flag already specified", xflag);
860 			xflag = ch;
861 			break;
862 		case 'c':
863 			confirm = 1;
864 			break;
865 		case 'm':
866 			minleft = (u_int)strtonum(optarg, 1, UINT_MAX, NULL);
867 			if (minleft == 0) {
868 				usage();
869 				ret = 1;
870 				goto done;
871 			}
872 			break;
873 		case 'M':
874 			maxsign = (u_int)strtonum(optarg, 1, UINT_MAX, NULL);
875 			if (maxsign == 0) {
876 				usage();
877 				ret = 1;
878 				goto done;
879 			}
880 			break;
881 		case 'd':
882 			deleting = 1;
883 			break;
884 		case 'D':
885 			Dflag = 1;
886 			break;
887 		case 's':
888 			pkcs11provider = optarg;
889 			break;
890 		case 'S':
891 			skprovider = optarg;
892 			break;
893 		case 'e':
894 			deleting = 1;
895 			pkcs11provider = optarg;
896 			break;
897 		case 't':
898 			if ((lifetime = convtime(optarg)) == -1 ||
899 			    lifetime < 0 || (u_long)lifetime > UINT32_MAX) {
900 				fprintf(stderr, "Invalid lifetime\n");
901 				ret = 1;
902 				goto done;
903 			}
904 			break;
905 		case 'q':
906 			qflag = 1;
907 			break;
908 		case 'T':
909 			Tflag = 1;
910 			break;
911 		default:
912 			usage();
913 			ret = 1;
914 			goto done;
915 		}
916 	}
917 	log_init(__progname, log_level, log_facility, 1);
918 
919 	if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1)
920 		fatal("Invalid combination of actions");
921 	else if (xflag) {
922 		if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1)
923 			ret = 1;
924 		goto done;
925 	} else if (lflag) {
926 		if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1)
927 			ret = 1;
928 		goto done;
929 	} else if (Dflag) {
930 		if (delete_all(agent_fd, qflag) == -1)
931 			ret = 1;
932 		goto done;
933 	}
934 
935 #ifdef ENABLE_SK_INTERNAL
936 	if (skprovider == NULL)
937 		skprovider = "internal";
938 #endif
939 
940 	if (hostkey_files == NULL) {
941 		/* use defaults from readconf.c */
942 		stringlist_append(&hostkey_files, _PATH_SSH_USER_HOSTFILE);
943 		stringlist_append(&hostkey_files, _PATH_SSH_USER_HOSTFILE2);
944 		stringlist_append(&hostkey_files, _PATH_SSH_SYSTEM_HOSTFILE);
945 		stringlist_append(&hostkey_files, _PATH_SSH_SYSTEM_HOSTFILE2);
946 	}
947 	if (dest_constraint_strings != NULL) {
948 		for (i = 0; dest_constraint_strings[i] != NULL; i++) {
949 			parse_dest_constraint(dest_constraint_strings[i],
950 			  &dest_constraints, &ndest_constraints, hostkey_files);
951 		}
952 	}
953 
954 	argc -= optind;
955 	argv += optind;
956 	if (Tflag) {
957 		if (argc <= 0)
958 			fatal("no keys to test");
959 		for (r = i = 0; i < argc; i++)
960 			r |= test_key(agent_fd, argv[i]);
961 		ret = r == 0 ? 0 : 1;
962 		goto done;
963 	}
964 	if (pkcs11provider != NULL) {
965 		if (update_card(agent_fd, !deleting, pkcs11provider,
966 		    qflag, dest_constraints, ndest_constraints) == -1)
967 			ret = 1;
968 		goto done;
969 	}
970 	if (do_download) {
971 		if (skprovider == NULL)
972 			fatal("Cannot download keys without provider");
973 		if (load_resident_keys(agent_fd, skprovider, qflag,
974 		    dest_constraints, ndest_constraints) != 0)
975 			ret = 1;
976 		goto done;
977 	}
978 	if (argc == 0) {
979 		char buf[PATH_MAX];
980 		struct passwd *pw;
981 		struct stat st;
982 		int count = 0;
983 
984 		if ((pw = getpwuid(getuid())) == NULL) {
985 			fprintf(stderr, "No user found with uid %u\n",
986 			    (u_int)getuid());
987 			ret = 1;
988 			goto done;
989 		}
990 
991 		for (i = 0; default_files[i]; i++) {
992 			snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir,
993 			    default_files[i]);
994 			if (stat(buf, &st) == -1)
995 				continue;
996 			if (do_file(agent_fd, deleting, key_only, buf,
997 			    qflag, skprovider,
998 			    dest_constraints, ndest_constraints) == -1)
999 				ret = 1;
1000 			else
1001 				count++;
1002 		}
1003 		if (count == 0)
1004 			ret = 1;
1005 	} else {
1006 		for (i = 0; i < argc; i++) {
1007 			if (do_file(agent_fd, deleting, key_only,
1008 			    argv[i], qflag, skprovider,
1009 			    dest_constraints, ndest_constraints) == -1)
1010 				ret = 1;
1011 		}
1012 	}
1013 done:
1014 	clear_pass();
1015 	ssh_close_authentication_socket(agent_fd);
1016 	return ret;
1017 }
1018