xref: /freebsd/crypto/openssh/ssh-add.c (revision aa1a8ff2d6dbc51ef058f46f3db5a8bb77967145)
1 /* $OpenBSD: ssh-add.c,v 1.172 2024/01/11 01:45:36 djm 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 #ifdef WITH_DSA
89 	_PATH_SSH_CLIENT_ID_DSA,
90 #endif
91 	NULL
92 };
93 
94 static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
95 
96 /* Default lifetime (0 == forever) */
97 static int lifetime = 0;
98 
99 /* User has to confirm key use */
100 static int confirm = 0;
101 
102 /* Maximum number of signatures (XMSS) */
103 static u_int maxsign = 0;
104 static u_int minleft = 0;
105 
106 /* we keep a cache of one passphrase */
107 static char *pass = NULL;
108 static void
109 clear_pass(void)
110 {
111 	if (pass) {
112 		freezero(pass, strlen(pass));
113 		pass = NULL;
114 	}
115 }
116 
117 static int
118 delete_one(int agent_fd, const struct sshkey *key, const char *comment,
119     const char *path, int qflag)
120 {
121 	int r;
122 
123 	if ((r = ssh_remove_identity(agent_fd, key)) != 0) {
124 		fprintf(stderr, "Could not remove identity \"%s\": %s\n",
125 		    path, ssh_err(r));
126 		return r;
127 	}
128 	if (!qflag) {
129 		fprintf(stderr, "Identity removed: %s %s (%s)\n", path,
130 		    sshkey_type(key), comment ? comment : "no comment");
131 	}
132 	return 0;
133 }
134 
135 static int
136 delete_stdin(int agent_fd, int qflag, int key_only, int cert_only)
137 {
138 	char *line = NULL, *cp;
139 	size_t linesize = 0;
140 	struct sshkey *key = NULL;
141 	int lnum = 0, r, ret = -1;
142 
143 	while (getline(&line, &linesize, stdin) != -1) {
144 		lnum++;
145 		sshkey_free(key);
146 		key = NULL;
147 		line[strcspn(line, "\n")] = '\0';
148 		cp = line + strspn(line, " \t");
149 		if (*cp == '#' || *cp == '\0')
150 			continue;
151 		if ((key = sshkey_new(KEY_UNSPEC)) == NULL)
152 			fatal_f("sshkey_new");
153 		if ((r = sshkey_read(key, &cp)) != 0) {
154 			error_r(r, "(stdin):%d: invalid key", lnum);
155 			continue;
156 		}
157 		if ((!key_only && !cert_only) ||
158 		    (key_only && !sshkey_is_cert(key)) ||
159 		    (cert_only && sshkey_is_cert(key))) {
160 			if (delete_one(agent_fd, key, cp,
161 			    "(stdin)", qflag) == 0)
162 				ret = 0;
163 		}
164 	}
165 	sshkey_free(key);
166 	free(line);
167 	return ret;
168 }
169 
170 static int
171 delete_file(int agent_fd, const char *filename, int key_only,
172     int cert_only, int qflag)
173 {
174 	struct sshkey *public, *cert = NULL;
175 	char *certpath = NULL, *comment = NULL;
176 	int r, ret = -1;
177 
178 	if (strcmp(filename, "-") == 0)
179 		return delete_stdin(agent_fd, qflag, key_only, cert_only);
180 
181 	if ((r = sshkey_load_public(filename, &public,  &comment)) != 0) {
182 		printf("Bad key file %s: %s\n", filename, ssh_err(r));
183 		return -1;
184 	}
185 	if ((!key_only && !cert_only) ||
186 	    (key_only && !sshkey_is_cert(public)) ||
187 	    (cert_only && sshkey_is_cert(public))) {
188 		if (delete_one(agent_fd, public, comment, filename, qflag) == 0)
189 			ret = 0;
190 	}
191 
192 	if (key_only)
193 		goto out;
194 
195 	/* Now try to delete the corresponding certificate too */
196 	free(comment);
197 	comment = NULL;
198 	xasprintf(&certpath, "%s-cert.pub", filename);
199 	if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) {
200 		if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
201 			error_r(r, "Failed to load certificate \"%s\"", certpath);
202 		goto out;
203 	}
204 
205 	if (!sshkey_equal_public(cert, public))
206 		fatal("Certificate %s does not match private key %s",
207 		    certpath, filename);
208 
209 	if (delete_one(agent_fd, cert, comment, certpath, qflag) == 0)
210 		ret = 0;
211 
212  out:
213 	sshkey_free(cert);
214 	sshkey_free(public);
215 	free(certpath);
216 	free(comment);
217 
218 	return ret;
219 }
220 
221 /* Send a request to remove all identities. */
222 static int
223 delete_all(int agent_fd, int qflag)
224 {
225 	int ret = -1;
226 
227 	/*
228 	 * Since the agent might be forwarded, old or non-OpenSSH, when asked
229 	 * to remove all keys, attempt to remove both protocol v.1 and v.2
230 	 * keys.
231 	 */
232 	if (ssh_remove_all_identities(agent_fd, 2) == 0)
233 		ret = 0;
234 	/* ignore error-code for ssh1 */
235 	ssh_remove_all_identities(agent_fd, 1);
236 
237 	if (ret != 0)
238 		fprintf(stderr, "Failed to remove all identities.\n");
239 	else if (!qflag)
240 		fprintf(stderr, "All identities removed.\n");
241 
242 	return ret;
243 }
244 
245 static int
246 add_file(int agent_fd, const char *filename, int key_only, int cert_only,
247     int qflag, const char *skprovider,
248     struct dest_constraint **dest_constraints,
249     size_t ndest_constraints)
250 {
251 	struct sshkey *private, *cert;
252 	char *comment = NULL;
253 	char msg[1024], *certpath = NULL;
254 	int r, fd, ret = -1;
255 	size_t i;
256 	u_int32_t left;
257 	struct sshbuf *keyblob;
258 	struct ssh_identitylist *idlist;
259 
260 	if (strcmp(filename, "-") == 0) {
261 		fd = STDIN_FILENO;
262 		filename = "(stdin)";
263 	} else if ((fd = open(filename, O_RDONLY)) == -1) {
264 		perror(filename);
265 		return -1;
266 	}
267 
268 	/*
269 	 * Since we'll try to load a keyfile multiple times, permission errors
270 	 * will occur multiple times, so check perms first and bail if wrong.
271 	 */
272 	if (fd != STDIN_FILENO) {
273 		if (sshkey_perm_ok(fd, filename) != 0) {
274 			close(fd);
275 			return -1;
276 		}
277 	}
278 	if ((r = sshbuf_load_fd(fd, &keyblob)) != 0) {
279 		fprintf(stderr, "Error loading key \"%s\": %s\n",
280 		    filename, ssh_err(r));
281 		sshbuf_free(keyblob);
282 		close(fd);
283 		return -1;
284 	}
285 	close(fd);
286 
287 	/* At first, try empty passphrase */
288 	if ((r = sshkey_parse_private_fileblob(keyblob, "", &private,
289 	    &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
290 		fprintf(stderr, "Error loading key \"%s\": %s\n",
291 		    filename, ssh_err(r));
292 		goto fail_load;
293 	}
294 	/* try last */
295 	if (private == NULL && pass != NULL) {
296 		if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private,
297 		    &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
298 			fprintf(stderr, "Error loading key \"%s\": %s\n",
299 			    filename, ssh_err(r));
300 			goto fail_load;
301 		}
302 	}
303 	if (private == NULL) {
304 		/* clear passphrase since it did not work */
305 		clear_pass();
306 		snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ",
307 		    filename, confirm ? " (will confirm each use)" : "");
308 		for (;;) {
309 			pass = read_passphrase(msg, RP_ALLOW_STDIN);
310 			if (strcmp(pass, "") == 0)
311 				goto fail_load;
312 			if ((r = sshkey_parse_private_fileblob(keyblob, pass,
313 			    &private, &comment)) == 0)
314 				break;
315 			else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
316 				fprintf(stderr,
317 				    "Error loading key \"%s\": %s\n",
318 				    filename, ssh_err(r));
319  fail_load:
320 				clear_pass();
321 				sshbuf_free(keyblob);
322 				return -1;
323 			}
324 			clear_pass();
325 			snprintf(msg, sizeof msg,
326 			    "Bad passphrase, try again for %s%s: ", filename,
327 			    confirm ? " (will confirm each use)" : "");
328 		}
329 	}
330 	if (comment == NULL || *comment == '\0')
331 		comment = xstrdup(filename);
332 	sshbuf_free(keyblob);
333 
334 	/* For XMSS */
335 	if ((r = sshkey_set_filename(private, filename)) != 0) {
336 		fprintf(stderr, "Could not add filename to private key: %s (%s)\n",
337 		    filename, comment);
338 		goto out;
339 	}
340 	if (maxsign && minleft &&
341 	    (r = ssh_fetch_identitylist(agent_fd, &idlist)) == 0) {
342 		for (i = 0; i < idlist->nkeys; i++) {
343 			if (!sshkey_equal_public(idlist->keys[i], private))
344 				continue;
345 			left = sshkey_signatures_left(idlist->keys[i]);
346 			if (left < minleft) {
347 				fprintf(stderr,
348 				    "Only %d signatures left.\n", left);
349 				break;
350 			}
351 			fprintf(stderr, "Skipping update: ");
352 			if (left == minleft) {
353 				fprintf(stderr,
354 				    "required signatures left (%d).\n", left);
355 			} else {
356 				fprintf(stderr,
357 				    "more signatures left (%d) than"
358 				    " required (%d).\n", left, minleft);
359 			}
360 			ssh_free_identitylist(idlist);
361 			goto out;
362 		}
363 		ssh_free_identitylist(idlist);
364 	}
365 
366 	if (sshkey_is_sk(private)) {
367 		if (skprovider == NULL) {
368 			fprintf(stderr, "Cannot load FIDO key %s "
369 			    "without provider\n", filename);
370 			goto out;
371 		}
372 	} else {
373 		/* Don't send provider constraint for other keys */
374 		skprovider = NULL;
375 	}
376 
377 	if (!cert_only &&
378 	    (r = ssh_add_identity_constrained(agent_fd, private, comment,
379 	    lifetime, confirm, maxsign, skprovider,
380 	    dest_constraints, ndest_constraints)) == 0) {
381 		ret = 0;
382 		if (!qflag) {
383 			fprintf(stderr, "Identity added: %s (%s)\n",
384 			    filename, comment);
385 			if (lifetime != 0) {
386 				fprintf(stderr,
387 				    "Lifetime set to %d seconds\n", lifetime);
388 			}
389 			if (confirm != 0) {
390 				fprintf(stderr, "The user must confirm "
391 				    "each use of the key\n");
392 			}
393 		}
394 	} else {
395 		fprintf(stderr, "Could not add identity \"%s\": %s\n",
396 		    filename, ssh_err(r));
397 	}
398 
399 	/* Skip trying to load the cert if requested */
400 	if (key_only)
401 		goto out;
402 
403 	/* Now try to add the certificate flavour too */
404 	xasprintf(&certpath, "%s-cert.pub", filename);
405 	if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) {
406 		if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
407 			error_r(r, "Failed to load certificate \"%s\"",
408 			    certpath);
409 		goto out;
410 	}
411 
412 	if (!sshkey_equal_public(cert, private)) {
413 		error("Certificate %s does not match private key %s",
414 		    certpath, filename);
415 		sshkey_free(cert);
416 		goto out;
417 	}
418 
419 	/* Graft with private bits */
420 	if ((r = sshkey_to_certified(private)) != 0) {
421 		error_fr(r, "sshkey_to_certified");
422 		sshkey_free(cert);
423 		goto out;
424 	}
425 	if ((r = sshkey_cert_copy(cert, private)) != 0) {
426 		error_fr(r, "sshkey_cert_copy");
427 		sshkey_free(cert);
428 		goto out;
429 	}
430 	sshkey_free(cert);
431 
432 	if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
433 	    lifetime, confirm, maxsign, skprovider,
434 	    dest_constraints, ndest_constraints)) != 0) {
435 		error_r(r, "Certificate %s (%s) add failed", certpath,
436 		    private->cert->key_id);
437 		goto out;
438 	}
439 	/* success */
440 	if (!qflag) {
441 		fprintf(stderr, "Certificate added: %s (%s)\n", certpath,
442 		    private->cert->key_id);
443 		if (lifetime != 0) {
444 			fprintf(stderr, "Lifetime set to %d seconds\n",
445 			    lifetime);
446 		}
447 		if (confirm != 0) {
448 			fprintf(stderr, "The user must confirm each use "
449 			    "of the key\n");
450 		}
451 	}
452 
453  out:
454 	free(certpath);
455 	free(comment);
456 	sshkey_free(private);
457 
458 	return ret;
459 }
460 
461 static int
462 update_card(int agent_fd, int add, const char *id, int qflag,
463     int key_only, int cert_only,
464     struct dest_constraint **dest_constraints, size_t ndest_constraints,
465     struct sshkey **certs, size_t ncerts)
466 {
467 	char *pin = NULL;
468 	int r, ret = -1;
469 
470 	if (key_only)
471 		ncerts = 0;
472 
473 	if (add) {
474 		if ((pin = read_passphrase("Enter passphrase for PKCS#11: ",
475 		    RP_ALLOW_STDIN)) == NULL)
476 			return -1;
477 	}
478 
479 	if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin,
480 	    lifetime, confirm, dest_constraints, ndest_constraints,
481 	    cert_only, certs, ncerts)) == 0) {
482 		ret = 0;
483 		if (!qflag) {
484 			fprintf(stderr, "Card %s: %s\n",
485 			    add ? "added" : "removed", id);
486 		}
487 	} else {
488 		fprintf(stderr, "Could not %s card \"%s\": %s\n",
489 		    add ? "add" : "remove", id, ssh_err(r));
490 		ret = -1;
491 	}
492 	free(pin);
493 	return ret;
494 }
495 
496 static int
497 test_key(int agent_fd, const char *filename)
498 {
499 	struct sshkey *key = NULL;
500 	u_char *sig = NULL;
501 	const char *alg = NULL;
502 	size_t slen = 0;
503 	int r, ret = -1;
504 	char data[1024];
505 
506 	if ((r = sshkey_load_public(filename, &key, NULL)) != 0) {
507 		error_r(r, "Couldn't read public key %s", filename);
508 		return -1;
509 	}
510 	if (sshkey_type_plain(key->type) == KEY_RSA)
511 		alg = "rsa-sha2-256";
512 	arc4random_buf(data, sizeof(data));
513 	if ((r = ssh_agent_sign(agent_fd, key, &sig, &slen, data, sizeof(data),
514 	    alg, 0)) != 0) {
515 		error_r(r, "Agent signature failed for %s", filename);
516 		goto done;
517 	}
518 	if ((r = sshkey_verify(key, sig, slen, data, sizeof(data),
519 	    alg, 0, NULL)) != 0) {
520 		error_r(r, "Signature verification failed for %s", filename);
521 		goto done;
522 	}
523 	/* success */
524 	ret = 0;
525  done:
526 	free(sig);
527 	sshkey_free(key);
528 	return ret;
529 }
530 
531 static int
532 list_identities(int agent_fd, int do_fp)
533 {
534 	char *fp;
535 	int r;
536 	struct ssh_identitylist *idlist;
537 	u_int32_t left;
538 	size_t i;
539 
540 	if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) {
541 		if (r != SSH_ERR_AGENT_NO_IDENTITIES)
542 			fprintf(stderr, "error fetching identities: %s\n",
543 			    ssh_err(r));
544 		else
545 			printf("The agent has no identities.\n");
546 		return -1;
547 	}
548 	for (i = 0; i < idlist->nkeys; i++) {
549 		if (do_fp) {
550 			fp = sshkey_fingerprint(idlist->keys[i],
551 			    fingerprint_hash, SSH_FP_DEFAULT);
552 			printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]),
553 			    fp == NULL ? "(null)" : fp, idlist->comments[i],
554 			    sshkey_type(idlist->keys[i]));
555 			free(fp);
556 		} else {
557 			if ((r = sshkey_write(idlist->keys[i], stdout)) != 0) {
558 				fprintf(stderr, "sshkey_write: %s\n",
559 				    ssh_err(r));
560 				continue;
561 			}
562 			fprintf(stdout, " %s", idlist->comments[i]);
563 			left = sshkey_signatures_left(idlist->keys[i]);
564 			if (left > 0)
565 				fprintf(stdout,
566 				    " [signatures left %d]", left);
567 			fprintf(stdout, "\n");
568 		}
569 	}
570 	ssh_free_identitylist(idlist);
571 	return 0;
572 }
573 
574 static int
575 lock_agent(int agent_fd, int lock)
576 {
577 	char prompt[100], *p1, *p2;
578 	int r, passok = 1, ret = -1;
579 
580 	strlcpy(prompt, "Enter lock password: ", sizeof(prompt));
581 	p1 = read_passphrase(prompt, RP_ALLOW_STDIN);
582 	if (lock) {
583 		strlcpy(prompt, "Again: ", sizeof prompt);
584 		p2 = read_passphrase(prompt, RP_ALLOW_STDIN);
585 		if (strcmp(p1, p2) != 0) {
586 			fprintf(stderr, "Passwords do not match.\n");
587 			passok = 0;
588 		}
589 		freezero(p2, strlen(p2));
590 	}
591 	if (passok) {
592 		if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) {
593 			fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un");
594 			ret = 0;
595 		} else {
596 			fprintf(stderr, "Failed to %slock agent: %s\n",
597 			    lock ? "" : "un", ssh_err(r));
598 		}
599 	}
600 	freezero(p1, strlen(p1));
601 	return (ret);
602 }
603 
604 static int
605 load_resident_keys(int agent_fd, const char *skprovider, int qflag,
606     struct dest_constraint **dest_constraints, size_t ndest_constraints)
607 {
608 	struct sshsk_resident_key **srks;
609 	size_t nsrks, i;
610 	struct sshkey *key;
611 	int r, ok = 0;
612 	char *fp;
613 
614 	pass = read_passphrase("Enter PIN for authenticator: ", RP_ALLOW_STDIN);
615 	if ((r = sshsk_load_resident(skprovider, NULL, pass, 0,
616 	    &srks, &nsrks)) != 0) {
617 		error_r(r, "Unable to load resident keys");
618 		return r;
619 	}
620 	for (i = 0; i < nsrks; i++) {
621 		key = srks[i]->key;
622 		if ((fp = sshkey_fingerprint(key,
623 		    fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
624 			fatal_f("sshkey_fingerprint failed");
625 		if ((r = ssh_add_identity_constrained(agent_fd, key, "",
626 		    lifetime, confirm, maxsign, skprovider,
627 		    dest_constraints, ndest_constraints)) != 0) {
628 			error("Unable to add key %s %s",
629 			    sshkey_type(key), fp);
630 			free(fp);
631 			ok = r;
632 			continue;
633 		}
634 		if (ok == 0)
635 			ok = 1;
636 		if (!qflag) {
637 			fprintf(stderr, "Resident identity added: %s %s\n",
638 			    sshkey_type(key), fp);
639 			if (lifetime != 0) {
640 				fprintf(stderr,
641 				    "Lifetime set to %d seconds\n", lifetime);
642 			}
643 			if (confirm != 0) {
644 				fprintf(stderr, "The user must confirm "
645 				    "each use of the key\n");
646 			}
647 		}
648 		free(fp);
649 	}
650 	sshsk_free_resident_keys(srks, nsrks);
651 	if (nsrks == 0)
652 		return SSH_ERR_KEY_NOT_FOUND;
653 	return ok == 1 ? 0 : ok;
654 }
655 
656 static int
657 do_file(int agent_fd, int deleting, int key_only, int cert_only,
658     char *file, int qflag, const char *skprovider,
659     struct dest_constraint **dest_constraints, size_t ndest_constraints)
660 {
661 	if (deleting) {
662 		if (delete_file(agent_fd, file, key_only,
663 		    cert_only, qflag) == -1)
664 			return -1;
665 	} else {
666 		if (add_file(agent_fd, file, key_only, cert_only, qflag,
667 		    skprovider, dest_constraints, ndest_constraints) == -1)
668 			return -1;
669 	}
670 	return 0;
671 }
672 
673 /* Append string 's' to a NULL-terminated array of strings */
674 static void
675 stringlist_append(char ***listp, const char *s)
676 {
677 	size_t i = 0;
678 
679 	if (*listp == NULL)
680 		*listp = xcalloc(2, sizeof(**listp));
681 	else {
682 		for (i = 0; (*listp)[i] != NULL; i++)
683 			; /* count */
684 		*listp = xrecallocarray(*listp, i + 1, i + 2, sizeof(**listp));
685 	}
686 	(*listp)[i] = xstrdup(s);
687 }
688 
689 static void
690 parse_dest_constraint_hop(const char *s, struct dest_constraint_hop *dch,
691     char **hostkey_files)
692 {
693 	char *user = NULL, *host, *os, *path;
694 	size_t i;
695 	struct hostkeys *hostkeys;
696 	const struct hostkey_entry *hke;
697 	int r, want_ca;
698 
699 	memset(dch, '\0', sizeof(*dch));
700 	os = xstrdup(s);
701 	if ((host = strchr(os, '@')) == NULL)
702 		host = os;
703 	else {
704 		*host++ = '\0';
705 		user = os;
706 	}
707 	cleanhostname(host);
708 	/* Trivial case: username@ (all hosts) */
709 	if (*host == '\0') {
710 		if (user == NULL) {
711 			fatal("Invalid key destination constraint \"%s\": "
712 			    "does not specify user or host", s);
713 		}
714 		dch->user = xstrdup(user);
715 		/* other fields left blank */
716 		free(os);
717 		return;
718 	}
719 	if (hostkey_files == NULL)
720 		fatal_f("no hostkey files");
721 	/* Otherwise we need to look up the keys for this hostname */
722 	hostkeys = init_hostkeys();
723 	for (i = 0; hostkey_files[i]; i++) {
724 		path = tilde_expand_filename(hostkey_files[i], getuid());
725 		debug2_f("looking up host keys for \"%s\" in %s", host, path);
726                 load_hostkeys(hostkeys, host, path, 0);
727 		free(path);
728 	}
729 	dch->user = user == NULL ? NULL : xstrdup(user);
730 	dch->hostname = xstrdup(host);
731 	for (i = 0; i < hostkeys->num_entries; i++) {
732 		hke = hostkeys->entries + i;
733 		want_ca = hke->marker == MRK_CA;
734 		if (hke->marker != MRK_NONE && !want_ca)
735 			continue;
736 		debug3_f("%s%s%s: adding %s %skey from %s:%lu as key %u",
737 		    user == NULL ? "": user, user == NULL ? "" : "@",
738 		    host, sshkey_type(hke->key), want_ca ? "CA " : "",
739 		    hke->file, hke->line, dch->nkeys);
740 		dch->keys = xrecallocarray(dch->keys, dch->nkeys,
741 		    dch->nkeys + 1, sizeof(*dch->keys));
742 		dch->key_is_ca = xrecallocarray(dch->key_is_ca, dch->nkeys,
743 		    dch->nkeys + 1, sizeof(*dch->key_is_ca));
744 		if ((r = sshkey_from_private(hke->key,
745 		    &(dch->keys[dch->nkeys]))) != 0)
746 			fatal_fr(r, "sshkey_from_private");
747 		dch->key_is_ca[dch->nkeys] = want_ca;
748 		dch->nkeys++;
749 	}
750 	if (dch->nkeys == 0)
751 		fatal("No host keys found for destination \"%s\"", host);
752 	free_hostkeys(hostkeys);
753 	free(os);
754 	return;
755 }
756 
757 static void
758 parse_dest_constraint(const char *s, struct dest_constraint ***dcp,
759     size_t *ndcp, char **hostkey_files)
760 {
761 	struct dest_constraint *dc;
762 	char *os, *cp;
763 
764 	dc = xcalloc(1, sizeof(*dc));
765 	os = xstrdup(s);
766 	if ((cp = strchr(os, '>')) == NULL) {
767 		/* initial hop; no 'from' hop specified */
768 		parse_dest_constraint_hop(os, &dc->to, hostkey_files);
769 	} else {
770 		/* two hops specified */
771 		*(cp++) = '\0';
772 		parse_dest_constraint_hop(os, &dc->from, hostkey_files);
773 		parse_dest_constraint_hop(cp, &dc->to, hostkey_files);
774 		if (dc->from.user != NULL) {
775 			fatal("Invalid key constraint %s: cannot specify "
776 			    "user on 'from' host", os);
777 		}
778 	}
779 	/* XXX eliminate or error on duplicates */
780 	debug2_f("constraint %zu: %s%s%s (%u keys) > %s%s%s (%u keys)", *ndcp,
781 	    dc->from.user ? dc->from.user : "", dc->from.user ? "@" : "",
782 	    dc->from.hostname ? dc->from.hostname : "(ORIGIN)", dc->from.nkeys,
783 	    dc->to.user ? dc->to.user : "", dc->to.user ? "@" : "",
784 	    dc->to.hostname ? dc->to.hostname : "(ANY)", dc->to.nkeys);
785 	*dcp = xrecallocarray(*dcp, *ndcp, *ndcp + 1, sizeof(**dcp));
786 	(*dcp)[(*ndcp)++] = dc;
787 	free(os);
788 }
789 
790 
791 static void
792 usage(void)
793 {
794 	fprintf(stderr,
795 "usage: ssh-add [-CcDdKkLlqvXx] [-E fingerprint_hash] [-H hostkey_file]\n"
796 "               [-h destination_constraint] [-S provider] [-t life]\n"
797 #ifdef WITH_XMSS
798 "               [-M maxsign] [-m minleft]\n"
799 #endif
800 "               [file ...]\n"
801 "       ssh-add -s pkcs11 [-Cv] [certificate ...]\n"
802 "       ssh-add -e pkcs11\n"
803 "       ssh-add -T pubkey ...\n"
804 	);
805 }
806 
807 int
808 main(int argc, char **argv)
809 {
810 	extern char *optarg;
811 	extern int optind;
812 	int agent_fd;
813 	char *pkcs11provider = NULL, *skprovider = NULL;
814 	char **dest_constraint_strings = NULL, **hostkey_files = NULL;
815 	int r, i, ch, deleting = 0, ret = 0, key_only = 0, cert_only = 0;
816 	int do_download = 0, xflag = 0, lflag = 0, Dflag = 0;
817 	int qflag = 0, Tflag = 0;
818 	SyslogFacility log_facility = SYSLOG_FACILITY_AUTH;
819 	LogLevel log_level = SYSLOG_LEVEL_INFO;
820 	struct sshkey *k, **certs = NULL;
821 	struct dest_constraint **dest_constraints = NULL;
822 	size_t ndest_constraints = 0, ncerts = 0;
823 
824 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
825 	sanitise_stdfd();
826 
827 	__progname = ssh_get_progname(argv[0]);
828 	seed_rng();
829 
830 	log_init(__progname, log_level, log_facility, 1);
831 
832 	setvbuf(stdout, NULL, _IOLBF, 0);
833 
834 	/* First, get a connection to the authentication agent. */
835 	switch (r = ssh_get_authentication_socket(&agent_fd)) {
836 	case 0:
837 		break;
838 	case SSH_ERR_AGENT_NOT_PRESENT:
839 		fprintf(stderr, "Could not open a connection to your "
840 		    "authentication agent.\n");
841 		exit(2);
842 	default:
843 		fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r));
844 		exit(2);
845 	}
846 
847 	skprovider = getenv("SSH_SK_PROVIDER");
848 
849 	while ((ch = getopt(argc, argv, "vkKlLCcdDTxXE:e:h:H:M:m:qs:S:t:")) != -1) {
850 		switch (ch) {
851 		case 'v':
852 			if (log_level == SYSLOG_LEVEL_INFO)
853 				log_level = SYSLOG_LEVEL_DEBUG1;
854 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
855 				log_level++;
856 			break;
857 		case 'E':
858 			fingerprint_hash = ssh_digest_alg_by_name(optarg);
859 			if (fingerprint_hash == -1)
860 				fatal("Invalid hash algorithm \"%s\"", optarg);
861 			break;
862 		case 'H':
863 			stringlist_append(&hostkey_files, optarg);
864 			break;
865 		case 'h':
866 			stringlist_append(&dest_constraint_strings, optarg);
867 			break;
868 		case 'k':
869 			key_only = 1;
870 			break;
871 		case 'C':
872 			cert_only = 1;
873 			break;
874 		case 'K':
875 			do_download = 1;
876 			break;
877 		case 'l':
878 		case 'L':
879 			if (lflag != 0)
880 				fatal("-%c flag already specified", lflag);
881 			lflag = ch;
882 			break;
883 		case 'x':
884 		case 'X':
885 			if (xflag != 0)
886 				fatal("-%c flag already specified", xflag);
887 			xflag = ch;
888 			break;
889 		case 'c':
890 			confirm = 1;
891 			break;
892 		case 'm':
893 			minleft = (u_int)strtonum(optarg, 1, UINT_MAX, NULL);
894 			if (minleft == 0) {
895 				usage();
896 				ret = 1;
897 				goto done;
898 			}
899 			break;
900 		case 'M':
901 			maxsign = (u_int)strtonum(optarg, 1, UINT_MAX, NULL);
902 			if (maxsign == 0) {
903 				usage();
904 				ret = 1;
905 				goto done;
906 			}
907 			break;
908 		case 'd':
909 			deleting = 1;
910 			break;
911 		case 'D':
912 			Dflag = 1;
913 			break;
914 		case 's':
915 			pkcs11provider = optarg;
916 			break;
917 		case 'S':
918 			skprovider = optarg;
919 			break;
920 		case 'e':
921 			deleting = 1;
922 			pkcs11provider = optarg;
923 			break;
924 		case 't':
925 			if ((lifetime = convtime(optarg)) == -1 ||
926 			    lifetime < 0 || (u_long)lifetime > UINT32_MAX) {
927 				fprintf(stderr, "Invalid lifetime\n");
928 				ret = 1;
929 				goto done;
930 			}
931 			break;
932 		case 'q':
933 			qflag = 1;
934 			break;
935 		case 'T':
936 			Tflag = 1;
937 			break;
938 		default:
939 			usage();
940 			ret = 1;
941 			goto done;
942 		}
943 	}
944 	log_init(__progname, log_level, log_facility, 1);
945 
946 	if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1)
947 		fatal("Invalid combination of actions");
948 	else if (xflag) {
949 		if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1)
950 			ret = 1;
951 		goto done;
952 	} else if (lflag) {
953 		if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1)
954 			ret = 1;
955 		goto done;
956 	} else if (Dflag) {
957 		if (delete_all(agent_fd, qflag) == -1)
958 			ret = 1;
959 		goto done;
960 	}
961 
962 #ifdef ENABLE_SK_INTERNAL
963 	if (skprovider == NULL)
964 		skprovider = "internal";
965 #endif
966 
967 	if (hostkey_files == NULL) {
968 		/* use defaults from readconf.c */
969 		stringlist_append(&hostkey_files, _PATH_SSH_USER_HOSTFILE);
970 		stringlist_append(&hostkey_files, _PATH_SSH_USER_HOSTFILE2);
971 		stringlist_append(&hostkey_files, _PATH_SSH_SYSTEM_HOSTFILE);
972 		stringlist_append(&hostkey_files, _PATH_SSH_SYSTEM_HOSTFILE2);
973 	}
974 	if (dest_constraint_strings != NULL) {
975 		for (i = 0; dest_constraint_strings[i] != NULL; i++) {
976 			parse_dest_constraint(dest_constraint_strings[i],
977 			  &dest_constraints, &ndest_constraints, hostkey_files);
978 		}
979 	}
980 
981 	argc -= optind;
982 	argv += optind;
983 	if (Tflag) {
984 		if (argc <= 0)
985 			fatal("no keys to test");
986 		for (r = i = 0; i < argc; i++)
987 			r |= test_key(agent_fd, argv[i]);
988 		ret = r == 0 ? 0 : 1;
989 		goto done;
990 	}
991 	if (pkcs11provider != NULL) {
992 		for (i = 0; i < argc; i++) {
993 			if ((r = sshkey_load_public(argv[i], &k, NULL)) != 0)
994 				fatal_fr(r, "load certificate %s", argv[i]);
995 			certs = xrecallocarray(certs, ncerts, ncerts + 1,
996 			    sizeof(*certs));
997 			debug2("%s: %s", argv[i], sshkey_ssh_name(k));
998 			certs[ncerts++] = k;
999 		}
1000 		debug2_f("loaded %zu certificates", ncerts);
1001 		if (update_card(agent_fd, !deleting, pkcs11provider,
1002 		    qflag, key_only, cert_only,
1003 		    dest_constraints, ndest_constraints,
1004 		    certs, ncerts) == -1)
1005 			ret = 1;
1006 		goto done;
1007 	}
1008 	if (do_download) {
1009 		if (skprovider == NULL)
1010 			fatal("Cannot download keys without provider");
1011 		if (load_resident_keys(agent_fd, skprovider, qflag,
1012 		    dest_constraints, ndest_constraints) != 0)
1013 			ret = 1;
1014 		goto done;
1015 	}
1016 	if (argc == 0) {
1017 		char buf[PATH_MAX];
1018 		struct passwd *pw;
1019 		struct stat st;
1020 		int count = 0;
1021 
1022 		if ((pw = getpwuid(getuid())) == NULL) {
1023 			fprintf(stderr, "No user found with uid %u\n",
1024 			    (u_int)getuid());
1025 			ret = 1;
1026 			goto done;
1027 		}
1028 
1029 		for (i = 0; default_files[i]; i++) {
1030 			snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir,
1031 			    default_files[i]);
1032 			if (stat(buf, &st) == -1)
1033 				continue;
1034 			if (do_file(agent_fd, deleting, key_only, cert_only,
1035 			    buf, qflag, skprovider,
1036 			    dest_constraints, ndest_constraints) == -1)
1037 				ret = 1;
1038 			else
1039 				count++;
1040 		}
1041 		if (count == 0)
1042 			ret = 1;
1043 	} else {
1044 		for (i = 0; i < argc; i++) {
1045 			if (do_file(agent_fd, deleting, key_only, cert_only,
1046 			    argv[i], qflag, skprovider,
1047 			    dest_constraints, ndest_constraints) == -1)
1048 				ret = 1;
1049 		}
1050 	}
1051 done:
1052 	clear_pass();
1053 	ssh_close_authentication_socket(agent_fd);
1054 	return ret;
1055 }
1056