1 /* $OpenBSD: ssh-add.c,v 1.136 2018/09/19 02:03:02 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 #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, int qflag) 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, "Failed to remove all identities.\n"); 185 else if (!qflag) 186 fprintf(stderr, "All identities removed.\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 ret = 0; 314 if (!qflag) { 315 fprintf(stderr, "Identity added: %s (%s)\n", 316 filename, comment); 317 if (lifetime != 0) { 318 fprintf(stderr, 319 "Lifetime set to %d seconds\n", lifetime); 320 } 321 if (confirm != 0) { 322 fprintf(stderr, "The user must confirm " 323 "each use of the key\n"); 324 } 325 } 326 } else { 327 fprintf(stderr, "Could not add identity \"%s\": %s\n", 328 filename, ssh_err(r)); 329 } 330 331 /* Skip trying to load the cert if requested */ 332 if (key_only) 333 goto out; 334 335 /* Now try to add the certificate flavour too */ 336 xasprintf(&certpath, "%s-cert.pub", filename); 337 if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) { 338 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 339 error("Failed to load certificate \"%s\": %s", 340 certpath, ssh_err(r)); 341 goto out; 342 } 343 344 if (!sshkey_equal_public(cert, private)) { 345 error("Certificate %s does not match private key %s", 346 certpath, filename); 347 sshkey_free(cert); 348 goto out; 349 } 350 351 /* Graft with private bits */ 352 if ((r = sshkey_to_certified(private)) != 0) { 353 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r)); 354 sshkey_free(cert); 355 goto out; 356 } 357 if ((r = sshkey_cert_copy(cert, private)) != 0) { 358 error("%s: sshkey_cert_copy: %s", __func__, ssh_err(r)); 359 sshkey_free(cert); 360 goto out; 361 } 362 sshkey_free(cert); 363 364 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 365 lifetime, confirm, maxsign)) != 0) { 366 error("Certificate %s (%s) add failed: %s", certpath, 367 private->cert->key_id, ssh_err(r)); 368 goto out; 369 } 370 /* success */ 371 if (!qflag) { 372 fprintf(stderr, "Certificate added: %s (%s)\n", certpath, 373 private->cert->key_id); 374 if (lifetime != 0) { 375 fprintf(stderr, "Lifetime set to %d seconds\n", 376 lifetime); 377 } 378 if (confirm != 0) { 379 fprintf(stderr, "The user must confirm each use " 380 "of the key\n"); 381 } 382 } 383 384 out: 385 free(certpath); 386 free(comment); 387 sshkey_free(private); 388 389 return ret; 390 } 391 392 static int 393 update_card(int agent_fd, int add, const char *id, int qflag) 394 { 395 char *pin = NULL; 396 int r, ret = -1; 397 398 if (add) { 399 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ", 400 RP_ALLOW_STDIN)) == NULL) 401 return -1; 402 } 403 404 if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin, 405 lifetime, confirm)) == 0) { 406 ret = 0; 407 if (!qflag) { 408 fprintf(stderr, "Card %s: %s\n", 409 add ? "added" : "removed", id); 410 } 411 } else { 412 fprintf(stderr, "Could not %s card \"%s\": %s\n", 413 add ? "add" : "remove", id, ssh_err(r)); 414 ret = -1; 415 } 416 free(pin); 417 return ret; 418 } 419 420 static int 421 list_identities(int agent_fd, int do_fp) 422 { 423 char *fp; 424 int r; 425 struct ssh_identitylist *idlist; 426 u_int32_t left; 427 size_t i; 428 429 if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 430 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 431 fprintf(stderr, "error fetching identities: %s\n", 432 ssh_err(r)); 433 else 434 printf("The agent has no identities.\n"); 435 return -1; 436 } 437 for (i = 0; i < idlist->nkeys; i++) { 438 if (do_fp) { 439 fp = sshkey_fingerprint(idlist->keys[i], 440 fingerprint_hash, SSH_FP_DEFAULT); 441 printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]), 442 fp == NULL ? "(null)" : fp, idlist->comments[i], 443 sshkey_type(idlist->keys[i])); 444 free(fp); 445 } else { 446 if ((r = sshkey_write(idlist->keys[i], stdout)) != 0) { 447 fprintf(stderr, "sshkey_write: %s\n", 448 ssh_err(r)); 449 continue; 450 } 451 fprintf(stdout, " %s", idlist->comments[i]); 452 left = sshkey_signatures_left(idlist->keys[i]); 453 if (left > 0) 454 fprintf(stdout, 455 " [signatures left %d]", left); 456 fprintf(stdout, "\n"); 457 } 458 } 459 ssh_free_identitylist(idlist); 460 return 0; 461 } 462 463 static int 464 lock_agent(int agent_fd, int lock) 465 { 466 char prompt[100], *p1, *p2; 467 int r, passok = 1, ret = -1; 468 469 strlcpy(prompt, "Enter lock password: ", sizeof(prompt)); 470 p1 = read_passphrase(prompt, RP_ALLOW_STDIN); 471 if (lock) { 472 strlcpy(prompt, "Again: ", sizeof prompt); 473 p2 = read_passphrase(prompt, RP_ALLOW_STDIN); 474 if (strcmp(p1, p2) != 0) { 475 fprintf(stderr, "Passwords do not match.\n"); 476 passok = 0; 477 } 478 explicit_bzero(p2, strlen(p2)); 479 free(p2); 480 } 481 if (passok) { 482 if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) { 483 fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un"); 484 ret = 0; 485 } else { 486 fprintf(stderr, "Failed to %slock agent: %s\n", 487 lock ? "" : "un", ssh_err(r)); 488 } 489 } 490 explicit_bzero(p1, strlen(p1)); 491 free(p1); 492 return (ret); 493 } 494 495 static int 496 do_file(int agent_fd, int deleting, int key_only, char *file, int qflag) 497 { 498 if (deleting) { 499 if (delete_file(agent_fd, file, key_only, qflag) == -1) 500 return -1; 501 } else { 502 if (add_file(agent_fd, file, key_only, qflag) == -1) 503 return -1; 504 } 505 return 0; 506 } 507 508 static void 509 usage(void) 510 { 511 fprintf(stderr, "usage: %s [options] [file ...]\n", __progname); 512 fprintf(stderr, "Options:\n"); 513 fprintf(stderr, " -l List fingerprints of all identities.\n"); 514 fprintf(stderr, " -E hash Specify hash algorithm used for fingerprints.\n"); 515 fprintf(stderr, " -L List public key parameters of all identities.\n"); 516 fprintf(stderr, " -k Load only keys and not certificates.\n"); 517 fprintf(stderr, " -c Require confirmation to sign using identities\n"); 518 fprintf(stderr, " -m minleft Maxsign is only changed if less than minleft are left (for XMSS)\n"); 519 fprintf(stderr, " -M maxsign Maximum number of signatures allowed (for XMSS)\n"); 520 fprintf(stderr, " -t life Set lifetime (in seconds) when adding identities.\n"); 521 fprintf(stderr, " -d Delete identity.\n"); 522 fprintf(stderr, " -D Delete all identities.\n"); 523 fprintf(stderr, " -x Lock agent.\n"); 524 fprintf(stderr, " -X Unlock agent.\n"); 525 fprintf(stderr, " -s pkcs11 Add keys from PKCS#11 provider.\n"); 526 fprintf(stderr, " -e pkcs11 Remove keys provided by PKCS#11 provider.\n"); 527 fprintf(stderr, " -q Be quiet after a successful operation.\n"); 528 } 529 530 int 531 main(int argc, char **argv) 532 { 533 extern char *optarg; 534 extern int optind; 535 int agent_fd; 536 char *pkcs11provider = NULL; 537 int r, i, ch, deleting = 0, ret = 0, key_only = 0; 538 int xflag = 0, lflag = 0, Dflag = 0, qflag = 0; 539 540 ssh_malloc_init(); /* must be called before any mallocs */ 541 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 542 sanitise_stdfd(); 543 544 __progname = ssh_get_progname(argv[0]); 545 seed_rng(); 546 547 #ifdef WITH_OPENSSL 548 OpenSSL_add_all_algorithms(); 549 #endif 550 551 setvbuf(stdout, NULL, _IOLBF, 0); 552 553 /* First, get a connection to the authentication agent. */ 554 switch (r = ssh_get_authentication_socket(&agent_fd)) { 555 case 0: 556 break; 557 case SSH_ERR_AGENT_NOT_PRESENT: 558 fprintf(stderr, "Could not open a connection to your " 559 "authentication agent.\n"); 560 exit(2); 561 default: 562 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r)); 563 exit(2); 564 } 565 566 while ((ch = getopt(argc, argv, "klLcdDxXE:e:M:m:qs:t:")) != -1) { 567 switch (ch) { 568 case 'E': 569 fingerprint_hash = ssh_digest_alg_by_name(optarg); 570 if (fingerprint_hash == -1) 571 fatal("Invalid hash algorithm \"%s\"", optarg); 572 break; 573 case 'k': 574 key_only = 1; 575 break; 576 case 'l': 577 case 'L': 578 if (lflag != 0) 579 fatal("-%c flag already specified", lflag); 580 lflag = ch; 581 break; 582 case 'x': 583 case 'X': 584 if (xflag != 0) 585 fatal("-%c flag already specified", xflag); 586 xflag = ch; 587 break; 588 case 'c': 589 confirm = 1; 590 break; 591 case 'm': 592 minleft = (int)strtonum(optarg, 1, UINT_MAX, NULL); 593 if (minleft == 0) { 594 usage(); 595 ret = 1; 596 goto done; 597 } 598 break; 599 case 'M': 600 maxsign = (int)strtonum(optarg, 1, UINT_MAX, NULL); 601 if (maxsign == 0) { 602 usage(); 603 ret = 1; 604 goto done; 605 } 606 break; 607 case 'd': 608 deleting = 1; 609 break; 610 case 'D': 611 Dflag = 1; 612 break; 613 case 's': 614 pkcs11provider = optarg; 615 break; 616 case 'e': 617 deleting = 1; 618 pkcs11provider = optarg; 619 break; 620 case 't': 621 if ((lifetime = convtime(optarg)) == -1) { 622 fprintf(stderr, "Invalid lifetime\n"); 623 ret = 1; 624 goto done; 625 } 626 break; 627 case 'q': 628 qflag = 1; 629 break; 630 default: 631 usage(); 632 ret = 1; 633 goto done; 634 } 635 } 636 637 if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1) 638 fatal("Invalid combination of actions"); 639 else if (xflag) { 640 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1) 641 ret = 1; 642 goto done; 643 } else if (lflag) { 644 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1) 645 ret = 1; 646 goto done; 647 } else if (Dflag) { 648 if (delete_all(agent_fd, qflag) == -1) 649 ret = 1; 650 goto done; 651 } 652 653 argc -= optind; 654 argv += optind; 655 if (pkcs11provider != NULL) { 656 if (update_card(agent_fd, !deleting, pkcs11provider, 657 qflag) == -1) 658 ret = 1; 659 goto done; 660 } 661 if (argc == 0) { 662 char buf[PATH_MAX]; 663 struct passwd *pw; 664 struct stat st; 665 int count = 0; 666 667 if ((pw = getpwuid(getuid())) == NULL) { 668 fprintf(stderr, "No user found with uid %u\n", 669 (u_int)getuid()); 670 ret = 1; 671 goto done; 672 } 673 674 for (i = 0; default_files[i]; i++) { 675 snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, 676 default_files[i]); 677 if (stat(buf, &st) < 0) 678 continue; 679 if (do_file(agent_fd, deleting, key_only, buf, 680 qflag) == -1) 681 ret = 1; 682 else 683 count++; 684 } 685 if (count == 0) 686 ret = 1; 687 } else { 688 for (i = 0; i < argc; i++) { 689 if (do_file(agent_fd, deleting, key_only, 690 argv[i], qflag) == -1) 691 ret = 1; 692 } 693 } 694 clear_pass(); 695 696 done: 697 ssh_close_authentication_socket(agent_fd); 698 return ret; 699 } 700