1 /* $OpenBSD: ssh-add.c,v 1.135 2018/02/23 15:58:37 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 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 "log.h" 59 #include "sshkey.h" 60 #include "sshbuf.h" 61 #include "authfd.h" 62 #include "authfile.h" 63 #include "pathnames.h" 64 #include "misc.h" 65 #include "ssherr.h" 66 #include "digest.h" 67 68 /* argv0 */ 69 extern char *__progname; 70 71 /* Default files to add */ 72 static char *default_files[] = { 73 #ifdef WITH_OPENSSL 74 _PATH_SSH_CLIENT_ID_RSA, 75 _PATH_SSH_CLIENT_ID_DSA, 76 #ifdef OPENSSL_HAS_ECC 77 _PATH_SSH_CLIENT_ID_ECDSA, 78 #endif 79 #endif /* WITH_OPENSSL */ 80 _PATH_SSH_CLIENT_ID_ED25519, 81 _PATH_SSH_CLIENT_ID_XMSS, 82 NULL 83 }; 84 85 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 86 87 /* Default lifetime (0 == forever) */ 88 static int lifetime = 0; 89 90 /* User has to confirm key use */ 91 static int confirm = 0; 92 93 /* Maximum number of signatures (XMSS) */ 94 static u_int maxsign = 0; 95 static u_int minleft = 0; 96 97 /* we keep a cache of one passphrase */ 98 static char *pass = NULL; 99 static void 100 clear_pass(void) 101 { 102 if (pass) { 103 explicit_bzero(pass, strlen(pass)); 104 free(pass); 105 pass = NULL; 106 } 107 } 108 109 static int 110 delete_file(int agent_fd, const char *filename, int key_only, int qflag) 111 { 112 struct sshkey *public, *cert = NULL; 113 char *certpath = NULL, *comment = NULL; 114 int r, ret = -1; 115 116 if ((r = sshkey_load_public(filename, &public, &comment)) != 0) { 117 printf("Bad key file %s: %s\n", filename, ssh_err(r)); 118 return -1; 119 } 120 if ((r = ssh_remove_identity(agent_fd, public)) == 0) { 121 if (!qflag) { 122 fprintf(stderr, "Identity removed: %s (%s)\n", 123 filename, comment); 124 } 125 ret = 0; 126 } else 127 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 128 filename, ssh_err(r)); 129 130 if (key_only) 131 goto out; 132 133 /* Now try to delete the corresponding certificate too */ 134 free(comment); 135 comment = NULL; 136 xasprintf(&certpath, "%s-cert.pub", filename); 137 if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) { 138 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 139 error("Failed to load certificate \"%s\": %s", 140 certpath, ssh_err(r)); 141 goto out; 142 } 143 144 if (!sshkey_equal_public(cert, public)) 145 fatal("Certificate %s does not match private key %s", 146 certpath, filename); 147 148 if ((r = ssh_remove_identity(agent_fd, cert)) == 0) { 149 if (!qflag) { 150 fprintf(stderr, "Identity removed: %s (%s)\n", 151 certpath, comment); 152 } 153 ret = 0; 154 } else 155 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 156 certpath, ssh_err(r)); 157 158 out: 159 sshkey_free(cert); 160 sshkey_free(public); 161 free(certpath); 162 free(comment); 163 164 return ret; 165 } 166 167 /* Send a request to remove all identities. */ 168 static int 169 delete_all(int agent_fd) 170 { 171 int ret = -1; 172 173 /* 174 * Since the agent might be forwarded, old or non-OpenSSH, when asked 175 * to remove all keys, attempt to remove both protocol v.1 and v.2 176 * keys. 177 */ 178 if (ssh_remove_all_identities(agent_fd, 2) == 0) 179 ret = 0; 180 /* ignore error-code for ssh1 */ 181 ssh_remove_all_identities(agent_fd, 1); 182 183 if (ret == 0) 184 fprintf(stderr, "All identities removed.\n"); 185 else 186 fprintf(stderr, "Failed to remove all identities.\n"); 187 188 return ret; 189 } 190 191 static int 192 add_file(int agent_fd, const char *filename, int key_only, int qflag) 193 { 194 struct sshkey *private, *cert; 195 char *comment = NULL; 196 char msg[1024], *certpath = NULL; 197 int r, fd, ret = -1; 198 size_t i; 199 u_int32_t left; 200 struct sshbuf *keyblob; 201 struct ssh_identitylist *idlist; 202 203 if (strcmp(filename, "-") == 0) { 204 fd = STDIN_FILENO; 205 filename = "(stdin)"; 206 } else if ((fd = open(filename, O_RDONLY)) < 0) { 207 perror(filename); 208 return -1; 209 } 210 211 /* 212 * Since we'll try to load a keyfile multiple times, permission errors 213 * will occur multiple times, so check perms first and bail if wrong. 214 */ 215 if (fd != STDIN_FILENO) { 216 if (sshkey_perm_ok(fd, filename) != 0) { 217 close(fd); 218 return -1; 219 } 220 } 221 if ((keyblob = sshbuf_new()) == NULL) 222 fatal("%s: sshbuf_new failed", __func__); 223 if ((r = sshkey_load_file(fd, keyblob)) != 0) { 224 fprintf(stderr, "Error loading key \"%s\": %s\n", 225 filename, ssh_err(r)); 226 sshbuf_free(keyblob); 227 close(fd); 228 return -1; 229 } 230 close(fd); 231 232 /* At first, try empty passphrase */ 233 if ((r = sshkey_parse_private_fileblob(keyblob, "", &private, 234 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 235 fprintf(stderr, "Error loading key \"%s\": %s\n", 236 filename, ssh_err(r)); 237 goto fail_load; 238 } 239 /* try last */ 240 if (private == NULL && pass != NULL) { 241 if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private, 242 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 243 fprintf(stderr, "Error loading key \"%s\": %s\n", 244 filename, ssh_err(r)); 245 goto fail_load; 246 } 247 } 248 if (private == NULL) { 249 /* clear passphrase since it did not work */ 250 clear_pass(); 251 snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ", 252 filename, confirm ? " (will confirm each use)" : ""); 253 for (;;) { 254 pass = read_passphrase(msg, RP_ALLOW_STDIN); 255 if (strcmp(pass, "") == 0) 256 goto fail_load; 257 if ((r = sshkey_parse_private_fileblob(keyblob, pass, 258 &private, &comment)) == 0) 259 break; 260 else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 261 fprintf(stderr, 262 "Error loading key \"%s\": %s\n", 263 filename, ssh_err(r)); 264 fail_load: 265 clear_pass(); 266 sshbuf_free(keyblob); 267 return -1; 268 } 269 clear_pass(); 270 snprintf(msg, sizeof msg, 271 "Bad passphrase, try again for %s%s: ", filename, 272 confirm ? " (will confirm each use)" : ""); 273 } 274 } 275 if (comment == NULL || *comment == '\0') 276 comment = xstrdup(filename); 277 sshbuf_free(keyblob); 278 279 /* For XMSS */ 280 if ((r = sshkey_set_filename(private, filename)) != 0) { 281 fprintf(stderr, "Could not add filename to private key: %s (%s)\n", 282 filename, comment); 283 goto out; 284 } 285 if (maxsign && minleft && 286 (r = ssh_fetch_identitylist(agent_fd, &idlist)) == 0) { 287 for (i = 0; i < idlist->nkeys; i++) { 288 if (!sshkey_equal_public(idlist->keys[i], private)) 289 continue; 290 left = sshkey_signatures_left(idlist->keys[i]); 291 if (left < minleft) { 292 fprintf(stderr, 293 "Only %d signatures left.\n", left); 294 break; 295 } 296 fprintf(stderr, "Skipping update: "); 297 if (left == minleft) { 298 fprintf(stderr, 299 "required signatures left (%d).\n", left); 300 } else { 301 fprintf(stderr, 302 "more signatures left (%d) than" 303 " required (%d).\n", left, minleft); 304 } 305 ssh_free_identitylist(idlist); 306 goto out; 307 } 308 ssh_free_identitylist(idlist); 309 } 310 311 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 312 lifetime, confirm, maxsign)) == 0) { 313 fprintf(stderr, "Identity added: %s (%s)\n", filename, comment); 314 ret = 0; 315 if (lifetime != 0) 316 fprintf(stderr, 317 "Lifetime set to %d seconds\n", lifetime); 318 if (confirm != 0) 319 fprintf(stderr, 320 "The user must confirm each use of the key\n"); 321 } else { 322 fprintf(stderr, "Could not add identity \"%s\": %s\n", 323 filename, ssh_err(r)); 324 } 325 326 /* Skip trying to load the cert if requested */ 327 if (key_only) 328 goto out; 329 330 /* Now try to add the certificate flavour too */ 331 xasprintf(&certpath, "%s-cert.pub", filename); 332 if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) { 333 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 334 error("Failed to load certificate \"%s\": %s", 335 certpath, ssh_err(r)); 336 goto out; 337 } 338 339 if (!sshkey_equal_public(cert, private)) { 340 error("Certificate %s does not match private key %s", 341 certpath, filename); 342 sshkey_free(cert); 343 goto out; 344 } 345 346 /* Graft with private bits */ 347 if ((r = sshkey_to_certified(private)) != 0) { 348 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r)); 349 sshkey_free(cert); 350 goto out; 351 } 352 if ((r = sshkey_cert_copy(cert, private)) != 0) { 353 error("%s: sshkey_cert_copy: %s", __func__, ssh_err(r)); 354 sshkey_free(cert); 355 goto out; 356 } 357 sshkey_free(cert); 358 359 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 360 lifetime, confirm, maxsign)) != 0) { 361 error("Certificate %s (%s) add failed: %s", certpath, 362 private->cert->key_id, ssh_err(r)); 363 goto out; 364 } 365 fprintf(stderr, "Certificate added: %s (%s)\n", certpath, 366 private->cert->key_id); 367 if (lifetime != 0) 368 fprintf(stderr, "Lifetime set to %d seconds\n", lifetime); 369 if (confirm != 0) 370 fprintf(stderr, "The user must confirm each use of the key\n"); 371 out: 372 free(certpath); 373 free(comment); 374 sshkey_free(private); 375 376 return ret; 377 } 378 379 static int 380 update_card(int agent_fd, int add, const char *id) 381 { 382 char *pin = NULL; 383 int r, ret = -1; 384 385 if (add) { 386 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ", 387 RP_ALLOW_STDIN)) == NULL) 388 return -1; 389 } 390 391 if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin, 392 lifetime, confirm)) == 0) { 393 fprintf(stderr, "Card %s: %s\n", 394 add ? "added" : "removed", id); 395 ret = 0; 396 } else { 397 fprintf(stderr, "Could not %s card \"%s\": %s\n", 398 add ? "add" : "remove", id, ssh_err(r)); 399 ret = -1; 400 } 401 free(pin); 402 return ret; 403 } 404 405 static int 406 list_identities(int agent_fd, int do_fp) 407 { 408 char *fp; 409 int r; 410 struct ssh_identitylist *idlist; 411 u_int32_t left; 412 size_t i; 413 414 if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 415 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 416 fprintf(stderr, "error fetching identities: %s\n", 417 ssh_err(r)); 418 else 419 printf("The agent has no identities.\n"); 420 return -1; 421 } 422 for (i = 0; i < idlist->nkeys; i++) { 423 if (do_fp) { 424 fp = sshkey_fingerprint(idlist->keys[i], 425 fingerprint_hash, SSH_FP_DEFAULT); 426 printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]), 427 fp == NULL ? "(null)" : fp, idlist->comments[i], 428 sshkey_type(idlist->keys[i])); 429 free(fp); 430 } else { 431 if ((r = sshkey_write(idlist->keys[i], stdout)) != 0) { 432 fprintf(stderr, "sshkey_write: %s\n", 433 ssh_err(r)); 434 continue; 435 } 436 fprintf(stdout, " %s", idlist->comments[i]); 437 left = sshkey_signatures_left(idlist->keys[i]); 438 if (left > 0) 439 fprintf(stdout, 440 " [signatures left %d]", left); 441 fprintf(stdout, "\n"); 442 } 443 } 444 ssh_free_identitylist(idlist); 445 return 0; 446 } 447 448 static int 449 lock_agent(int agent_fd, int lock) 450 { 451 char prompt[100], *p1, *p2; 452 int r, passok = 1, ret = -1; 453 454 strlcpy(prompt, "Enter lock password: ", sizeof(prompt)); 455 p1 = read_passphrase(prompt, RP_ALLOW_STDIN); 456 if (lock) { 457 strlcpy(prompt, "Again: ", sizeof prompt); 458 p2 = read_passphrase(prompt, RP_ALLOW_STDIN); 459 if (strcmp(p1, p2) != 0) { 460 fprintf(stderr, "Passwords do not match.\n"); 461 passok = 0; 462 } 463 explicit_bzero(p2, strlen(p2)); 464 free(p2); 465 } 466 if (passok) { 467 if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) { 468 fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un"); 469 ret = 0; 470 } else { 471 fprintf(stderr, "Failed to %slock agent: %s\n", 472 lock ? "" : "un", ssh_err(r)); 473 } 474 } 475 explicit_bzero(p1, strlen(p1)); 476 free(p1); 477 return (ret); 478 } 479 480 static int 481 do_file(int agent_fd, int deleting, int key_only, char *file, int qflag) 482 { 483 if (deleting) { 484 if (delete_file(agent_fd, file, key_only, qflag) == -1) 485 return -1; 486 } else { 487 if (add_file(agent_fd, file, key_only, qflag) == -1) 488 return -1; 489 } 490 return 0; 491 } 492 493 static void 494 usage(void) 495 { 496 fprintf(stderr, "usage: %s [options] [file ...]\n", __progname); 497 fprintf(stderr, "Options:\n"); 498 fprintf(stderr, " -l List fingerprints of all identities.\n"); 499 fprintf(stderr, " -E hash Specify hash algorithm used for fingerprints.\n"); 500 fprintf(stderr, " -L List public key parameters of all identities.\n"); 501 fprintf(stderr, " -k Load only keys and not certificates.\n"); 502 fprintf(stderr, " -c Require confirmation to sign using identities\n"); 503 fprintf(stderr, " -m minleft Maxsign is only changed if less than minleft are left (for XMSS)\n"); 504 fprintf(stderr, " -M maxsign Maximum number of signatures allowed (for XMSS)\n"); 505 fprintf(stderr, " -t life Set lifetime (in seconds) when adding identities.\n"); 506 fprintf(stderr, " -d Delete identity.\n"); 507 fprintf(stderr, " -D Delete all identities.\n"); 508 fprintf(stderr, " -x Lock agent.\n"); 509 fprintf(stderr, " -X Unlock agent.\n"); 510 fprintf(stderr, " -s pkcs11 Add keys from PKCS#11 provider.\n"); 511 fprintf(stderr, " -e pkcs11 Remove keys provided by PKCS#11 provider.\n"); 512 fprintf(stderr, " -q Be quiet after a successful operation.\n"); 513 } 514 515 int 516 main(int argc, char **argv) 517 { 518 extern char *optarg; 519 extern int optind; 520 int agent_fd; 521 char *pkcs11provider = NULL; 522 int r, i, ch, deleting = 0, ret = 0, key_only = 0; 523 int xflag = 0, lflag = 0, Dflag = 0, qflag = 0; 524 525 ssh_malloc_init(); /* must be called before any mallocs */ 526 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 527 sanitise_stdfd(); 528 529 __progname = ssh_get_progname(argv[0]); 530 seed_rng(); 531 532 #ifdef WITH_OPENSSL 533 OpenSSL_add_all_algorithms(); 534 #endif 535 536 setvbuf(stdout, NULL, _IOLBF, 0); 537 538 /* First, get a connection to the authentication agent. */ 539 switch (r = ssh_get_authentication_socket(&agent_fd)) { 540 case 0: 541 break; 542 case SSH_ERR_AGENT_NOT_PRESENT: 543 fprintf(stderr, "Could not open a connection to your " 544 "authentication agent.\n"); 545 exit(2); 546 default: 547 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r)); 548 exit(2); 549 } 550 551 while ((ch = getopt(argc, argv, "klLcdDxXE:e:M:m:qs:t:")) != -1) { 552 switch (ch) { 553 case 'E': 554 fingerprint_hash = ssh_digest_alg_by_name(optarg); 555 if (fingerprint_hash == -1) 556 fatal("Invalid hash algorithm \"%s\"", optarg); 557 break; 558 case 'k': 559 key_only = 1; 560 break; 561 case 'l': 562 case 'L': 563 if (lflag != 0) 564 fatal("-%c flag already specified", lflag); 565 lflag = ch; 566 break; 567 case 'x': 568 case 'X': 569 if (xflag != 0) 570 fatal("-%c flag already specified", xflag); 571 xflag = ch; 572 break; 573 case 'c': 574 confirm = 1; 575 break; 576 case 'm': 577 minleft = (int)strtonum(optarg, 1, UINT_MAX, NULL); 578 if (minleft == 0) { 579 usage(); 580 ret = 1; 581 goto done; 582 } 583 break; 584 case 'M': 585 maxsign = (int)strtonum(optarg, 1, UINT_MAX, NULL); 586 if (maxsign == 0) { 587 usage(); 588 ret = 1; 589 goto done; 590 } 591 break; 592 case 'd': 593 deleting = 1; 594 break; 595 case 'D': 596 Dflag = 1; 597 break; 598 case 's': 599 pkcs11provider = optarg; 600 break; 601 case 'e': 602 deleting = 1; 603 pkcs11provider = optarg; 604 break; 605 case 't': 606 if ((lifetime = convtime(optarg)) == -1) { 607 fprintf(stderr, "Invalid lifetime\n"); 608 ret = 1; 609 goto done; 610 } 611 break; 612 case 'q': 613 qflag = 1; 614 break; 615 default: 616 usage(); 617 ret = 1; 618 goto done; 619 } 620 } 621 622 if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1) 623 fatal("Invalid combination of actions"); 624 else if (xflag) { 625 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1) 626 ret = 1; 627 goto done; 628 } else if (lflag) { 629 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1) 630 ret = 1; 631 goto done; 632 } else if (Dflag) { 633 if (delete_all(agent_fd) == -1) 634 ret = 1; 635 goto done; 636 } 637 638 argc -= optind; 639 argv += optind; 640 if (pkcs11provider != NULL) { 641 if (update_card(agent_fd, !deleting, pkcs11provider) == -1) 642 ret = 1; 643 goto done; 644 } 645 if (argc == 0) { 646 char buf[PATH_MAX]; 647 struct passwd *pw; 648 struct stat st; 649 int count = 0; 650 651 if ((pw = getpwuid(getuid())) == NULL) { 652 fprintf(stderr, "No user found with uid %u\n", 653 (u_int)getuid()); 654 ret = 1; 655 goto done; 656 } 657 658 for (i = 0; default_files[i]; i++) { 659 snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, 660 default_files[i]); 661 if (stat(buf, &st) < 0) 662 continue; 663 if (do_file(agent_fd, deleting, key_only, buf, 664 qflag) == -1) 665 ret = 1; 666 else 667 count++; 668 } 669 if (count == 0) 670 ret = 1; 671 } else { 672 for (i = 0; i < argc; i++) { 673 if (do_file(agent_fd, deleting, key_only, 674 argv[i], qflag) == -1) 675 ret = 1; 676 } 677 } 678 clear_pass(); 679 680 done: 681 ssh_close_authentication_socket(agent_fd); 682 return ret; 683 } 684