1 /* $OpenBSD: ssh-add.c,v 1.134 2017/08/29 09:42:29 dlg 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 <sys/types.h> 39 #include <sys/stat.h> 40 41 #include <openssl/evp.h> 42 43 #include <errno.h> 44 #include <fcntl.h> 45 #include <pwd.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <unistd.h> 50 #include <limits.h> 51 52 #include "xmalloc.h" 53 #include "ssh.h" 54 #include "log.h" 55 #include "sshkey.h" 56 #include "sshbuf.h" 57 #include "authfd.h" 58 #include "authfile.h" 59 #include "pathnames.h" 60 #include "misc.h" 61 #include "ssherr.h" 62 #include "digest.h" 63 64 /* argv0 */ 65 extern char *__progname; 66 67 /* Default files to add */ 68 static char *default_files[] = { 69 _PATH_SSH_CLIENT_ID_RSA, 70 _PATH_SSH_CLIENT_ID_DSA, 71 _PATH_SSH_CLIENT_ID_ECDSA, 72 _PATH_SSH_CLIENT_ID_ED25519, 73 NULL 74 }; 75 76 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 77 78 /* Default lifetime (0 == forever) */ 79 static int lifetime = 0; 80 81 /* User has to confirm key use */ 82 static int confirm = 0; 83 84 /* we keep a cache of one passphrase */ 85 static char *pass = NULL; 86 static void 87 clear_pass(void) 88 { 89 if (pass) { 90 explicit_bzero(pass, strlen(pass)); 91 free(pass); 92 pass = NULL; 93 } 94 } 95 96 static int 97 delete_file(int agent_fd, const char *filename, int key_only, int qflag) 98 { 99 struct sshkey *public, *cert = NULL; 100 char *certpath = NULL, *comment = NULL; 101 int r, ret = -1; 102 103 if ((r = sshkey_load_public(filename, &public, &comment)) != 0) { 104 printf("Bad key file %s: %s\n", filename, ssh_err(r)); 105 return -1; 106 } 107 if ((r = ssh_remove_identity(agent_fd, public)) == 0) { 108 if (!qflag) { 109 fprintf(stderr, "Identity removed: %s (%s)\n", 110 filename, comment); 111 } 112 ret = 0; 113 } else 114 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 115 filename, ssh_err(r)); 116 117 if (key_only) 118 goto out; 119 120 /* Now try to delete the corresponding certificate too */ 121 free(comment); 122 comment = NULL; 123 xasprintf(&certpath, "%s-cert.pub", filename); 124 if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) { 125 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 126 error("Failed to load certificate \"%s\": %s", 127 certpath, ssh_err(r)); 128 goto out; 129 } 130 131 if (!sshkey_equal_public(cert, public)) 132 fatal("Certificate %s does not match private key %s", 133 certpath, filename); 134 135 if ((r = ssh_remove_identity(agent_fd, cert)) == 0) { 136 if (!qflag) { 137 fprintf(stderr, "Identity removed: %s (%s)\n", 138 certpath, comment); 139 } 140 ret = 0; 141 } else 142 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 143 certpath, ssh_err(r)); 144 145 out: 146 sshkey_free(cert); 147 sshkey_free(public); 148 free(certpath); 149 free(comment); 150 151 return ret; 152 } 153 154 /* Send a request to remove all identities. */ 155 static int 156 delete_all(int agent_fd) 157 { 158 int ret = -1; 159 160 /* 161 * Since the agent might be forwarded, old or non-OpenSSH, when asked 162 * to remove all keys, attempt to remove both protocol v.1 and v.2 163 * keys. 164 */ 165 if (ssh_remove_all_identities(agent_fd, 2) == 0) 166 ret = 0; 167 /* ignore error-code for ssh1 */ 168 ssh_remove_all_identities(agent_fd, 1); 169 170 if (ret == 0) 171 fprintf(stderr, "All identities removed.\n"); 172 else 173 fprintf(stderr, "Failed to remove all identities.\n"); 174 175 return ret; 176 } 177 178 static int 179 add_file(int agent_fd, const char *filename, int key_only, int qflag) 180 { 181 struct sshkey *private, *cert; 182 char *comment = NULL; 183 char msg[1024], *certpath = NULL; 184 int r, fd, ret = -1; 185 struct sshbuf *keyblob; 186 187 if (strcmp(filename, "-") == 0) { 188 fd = STDIN_FILENO; 189 filename = "(stdin)"; 190 } else if ((fd = open(filename, O_RDONLY)) < 0) { 191 perror(filename); 192 return -1; 193 } 194 195 /* 196 * Since we'll try to load a keyfile multiple times, permission errors 197 * will occur multiple times, so check perms first and bail if wrong. 198 */ 199 if (fd != STDIN_FILENO) { 200 if (sshkey_perm_ok(fd, filename) != 0) { 201 close(fd); 202 return -1; 203 } 204 } 205 if ((keyblob = sshbuf_new()) == NULL) 206 fatal("%s: sshbuf_new failed", __func__); 207 if ((r = sshkey_load_file(fd, keyblob)) != 0) { 208 fprintf(stderr, "Error loading key \"%s\": %s\n", 209 filename, ssh_err(r)); 210 sshbuf_free(keyblob); 211 close(fd); 212 return -1; 213 } 214 close(fd); 215 216 /* At first, try empty passphrase */ 217 if ((r = sshkey_parse_private_fileblob(keyblob, "", &private, 218 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 219 fprintf(stderr, "Error loading key \"%s\": %s\n", 220 filename, ssh_err(r)); 221 goto fail_load; 222 } 223 /* try last */ 224 if (private == NULL && pass != NULL) { 225 if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private, 226 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 227 fprintf(stderr, "Error loading key \"%s\": %s\n", 228 filename, ssh_err(r)); 229 goto fail_load; 230 } 231 } 232 if (private == NULL) { 233 /* clear passphrase since it did not work */ 234 clear_pass(); 235 snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ", 236 filename, confirm ? " (will confirm each use)" : ""); 237 for (;;) { 238 pass = read_passphrase(msg, RP_ALLOW_STDIN); 239 if (strcmp(pass, "") == 0) 240 goto fail_load; 241 if ((r = sshkey_parse_private_fileblob(keyblob, pass, 242 &private, &comment)) == 0) 243 break; 244 else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 245 fprintf(stderr, 246 "Error loading key \"%s\": %s\n", 247 filename, ssh_err(r)); 248 fail_load: 249 clear_pass(); 250 sshbuf_free(keyblob); 251 return -1; 252 } 253 clear_pass(); 254 snprintf(msg, sizeof msg, 255 "Bad passphrase, try again for %s%s: ", filename, 256 confirm ? " (will confirm each use)" : ""); 257 } 258 } 259 if (comment == NULL || *comment == '\0') 260 comment = xstrdup(filename); 261 sshbuf_free(keyblob); 262 263 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 264 lifetime, confirm)) == 0) { 265 fprintf(stderr, "Identity added: %s (%s)\n", filename, comment); 266 ret = 0; 267 if (lifetime != 0) 268 fprintf(stderr, 269 "Lifetime set to %d seconds\n", lifetime); 270 if (confirm != 0) 271 fprintf(stderr, 272 "The user must confirm each use of the key\n"); 273 } else { 274 fprintf(stderr, "Could not add identity \"%s\": %s\n", 275 filename, ssh_err(r)); 276 } 277 278 /* Skip trying to load the cert if requested */ 279 if (key_only) 280 goto out; 281 282 /* Now try to add the certificate flavour too */ 283 xasprintf(&certpath, "%s-cert.pub", filename); 284 if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) { 285 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 286 error("Failed to load certificate \"%s\": %s", 287 certpath, ssh_err(r)); 288 goto out; 289 } 290 291 if (!sshkey_equal_public(cert, private)) { 292 error("Certificate %s does not match private key %s", 293 certpath, filename); 294 sshkey_free(cert); 295 goto out; 296 } 297 298 /* Graft with private bits */ 299 if ((r = sshkey_to_certified(private)) != 0) { 300 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r)); 301 sshkey_free(cert); 302 goto out; 303 } 304 if ((r = sshkey_cert_copy(cert, private)) != 0) { 305 error("%s: sshkey_cert_copy: %s", __func__, ssh_err(r)); 306 sshkey_free(cert); 307 goto out; 308 } 309 sshkey_free(cert); 310 311 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 312 lifetime, confirm)) != 0) { 313 error("Certificate %s (%s) add failed: %s", certpath, 314 private->cert->key_id, ssh_err(r)); 315 goto out; 316 } 317 fprintf(stderr, "Certificate added: %s (%s)\n", certpath, 318 private->cert->key_id); 319 if (lifetime != 0) 320 fprintf(stderr, "Lifetime set to %d seconds\n", lifetime); 321 if (confirm != 0) 322 fprintf(stderr, "The user must confirm each use of the key\n"); 323 out: 324 free(certpath); 325 free(comment); 326 sshkey_free(private); 327 328 return ret; 329 } 330 331 static int 332 update_card(int agent_fd, int add, const char *id) 333 { 334 char *pin = NULL; 335 int r, ret = -1; 336 337 if (add) { 338 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ", 339 RP_ALLOW_STDIN)) == NULL) 340 return -1; 341 } 342 343 if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin, 344 lifetime, confirm)) == 0) { 345 fprintf(stderr, "Card %s: %s\n", 346 add ? "added" : "removed", id); 347 ret = 0; 348 } else { 349 fprintf(stderr, "Could not %s card \"%s\": %s\n", 350 add ? "add" : "remove", id, ssh_err(r)); 351 ret = -1; 352 } 353 free(pin); 354 return ret; 355 } 356 357 static int 358 list_identities(int agent_fd, int do_fp) 359 { 360 char *fp; 361 int r; 362 struct ssh_identitylist *idlist; 363 size_t i; 364 365 if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 366 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 367 fprintf(stderr, "error fetching identities: %s\n", 368 ssh_err(r)); 369 else 370 printf("The agent has no identities.\n"); 371 return -1; 372 } 373 for (i = 0; i < idlist->nkeys; i++) { 374 if (do_fp) { 375 fp = sshkey_fingerprint(idlist->keys[i], 376 fingerprint_hash, SSH_FP_DEFAULT); 377 printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]), 378 fp == NULL ? "(null)" : fp, idlist->comments[i], 379 sshkey_type(idlist->keys[i])); 380 free(fp); 381 } else { 382 if ((r = sshkey_write(idlist->keys[i], stdout)) != 0) { 383 fprintf(stderr, "sshkey_write: %s\n", 384 ssh_err(r)); 385 continue; 386 } 387 fprintf(stdout, " %s\n", idlist->comments[i]); 388 } 389 } 390 ssh_free_identitylist(idlist); 391 return 0; 392 } 393 394 static int 395 lock_agent(int agent_fd, int lock) 396 { 397 char prompt[100], *p1, *p2; 398 int r, passok = 1, ret = -1; 399 400 strlcpy(prompt, "Enter lock password: ", sizeof(prompt)); 401 p1 = read_passphrase(prompt, RP_ALLOW_STDIN); 402 if (lock) { 403 strlcpy(prompt, "Again: ", sizeof prompt); 404 p2 = read_passphrase(prompt, RP_ALLOW_STDIN); 405 if (strcmp(p1, p2) != 0) { 406 fprintf(stderr, "Passwords do not match.\n"); 407 passok = 0; 408 } 409 explicit_bzero(p2, strlen(p2)); 410 free(p2); 411 } 412 if (passok) { 413 if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) { 414 fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un"); 415 ret = 0; 416 } else { 417 fprintf(stderr, "Failed to %slock agent: %s\n", 418 lock ? "" : "un", ssh_err(r)); 419 } 420 } 421 explicit_bzero(p1, strlen(p1)); 422 free(p1); 423 return (ret); 424 } 425 426 static int 427 do_file(int agent_fd, int deleting, int key_only, char *file, int qflag) 428 { 429 if (deleting) { 430 if (delete_file(agent_fd, file, key_only, qflag) == -1) 431 return -1; 432 } else { 433 if (add_file(agent_fd, file, key_only, qflag) == -1) 434 return -1; 435 } 436 return 0; 437 } 438 439 static void 440 usage(void) 441 { 442 fprintf(stderr, "usage: %s [options] [file ...]\n", __progname); 443 fprintf(stderr, "Options:\n"); 444 fprintf(stderr, " -l List fingerprints of all identities.\n"); 445 fprintf(stderr, " -E hash Specify hash algorithm used for fingerprints.\n"); 446 fprintf(stderr, " -L List public key parameters of all identities.\n"); 447 fprintf(stderr, " -k Load only keys and not certificates.\n"); 448 fprintf(stderr, " -c Require confirmation to sign using identities\n"); 449 fprintf(stderr, " -t life Set lifetime (in seconds) when adding identities.\n"); 450 fprintf(stderr, " -d Delete identity.\n"); 451 fprintf(stderr, " -D Delete all identities.\n"); 452 fprintf(stderr, " -x Lock agent.\n"); 453 fprintf(stderr, " -X Unlock agent.\n"); 454 fprintf(stderr, " -s pkcs11 Add keys from PKCS#11 provider.\n"); 455 fprintf(stderr, " -e pkcs11 Remove keys provided by PKCS#11 provider.\n"); 456 fprintf(stderr, " -q Be quiet after a successful operation.\n"); 457 } 458 459 int 460 main(int argc, char **argv) 461 { 462 extern char *optarg; 463 extern int optind; 464 int agent_fd; 465 char *pkcs11provider = NULL; 466 int r, i, ch, deleting = 0, ret = 0, key_only = 0; 467 int xflag = 0, lflag = 0, Dflag = 0, qflag = 0; 468 469 ssh_malloc_init(); /* must be called before any mallocs */ 470 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 471 sanitise_stdfd(); 472 473 OpenSSL_add_all_algorithms(); 474 475 setvbuf(stdout, NULL, _IOLBF, 0); 476 477 /* First, get a connection to the authentication agent. */ 478 switch (r = ssh_get_authentication_socket(&agent_fd)) { 479 case 0: 480 break; 481 case SSH_ERR_AGENT_NOT_PRESENT: 482 fprintf(stderr, "Could not open a connection to your " 483 "authentication agent.\n"); 484 exit(2); 485 default: 486 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r)); 487 exit(2); 488 } 489 490 while ((ch = getopt(argc, argv, "klLcdDxXE:e:qs:t:")) != -1) { 491 switch (ch) { 492 case 'E': 493 fingerprint_hash = ssh_digest_alg_by_name(optarg); 494 if (fingerprint_hash == -1) 495 fatal("Invalid hash algorithm \"%s\"", optarg); 496 break; 497 case 'k': 498 key_only = 1; 499 break; 500 case 'l': 501 case 'L': 502 if (lflag != 0) 503 fatal("-%c flag already specified", lflag); 504 lflag = ch; 505 break; 506 case 'x': 507 case 'X': 508 if (xflag != 0) 509 fatal("-%c flag already specified", xflag); 510 xflag = ch; 511 break; 512 case 'c': 513 confirm = 1; 514 break; 515 case 'd': 516 deleting = 1; 517 break; 518 case 'D': 519 Dflag = 1; 520 break; 521 case 's': 522 pkcs11provider = optarg; 523 break; 524 case 'e': 525 deleting = 1; 526 pkcs11provider = optarg; 527 break; 528 case 't': 529 if ((lifetime = convtime(optarg)) == -1) { 530 fprintf(stderr, "Invalid lifetime\n"); 531 ret = 1; 532 goto done; 533 } 534 break; 535 case 'q': 536 qflag = 1; 537 break; 538 default: 539 usage(); 540 ret = 1; 541 goto done; 542 } 543 } 544 545 if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1) 546 fatal("Invalid combination of actions"); 547 else if (xflag) { 548 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1) 549 ret = 1; 550 goto done; 551 } else if (lflag) { 552 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1) 553 ret = 1; 554 goto done; 555 } else if (Dflag) { 556 if (delete_all(agent_fd) == -1) 557 ret = 1; 558 goto done; 559 } 560 561 argc -= optind; 562 argv += optind; 563 if (pkcs11provider != NULL) { 564 if (update_card(agent_fd, !deleting, pkcs11provider) == -1) 565 ret = 1; 566 goto done; 567 } 568 if (argc == 0) { 569 char buf[PATH_MAX]; 570 struct passwd *pw; 571 struct stat st; 572 int count = 0; 573 574 if ((pw = getpwuid(getuid())) == NULL) { 575 fprintf(stderr, "No user found with uid %u\n", 576 (u_int)getuid()); 577 ret = 1; 578 goto done; 579 } 580 581 for (i = 0; default_files[i]; i++) { 582 snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, 583 default_files[i]); 584 if (stat(buf, &st) < 0) 585 continue; 586 if (do_file(agent_fd, deleting, key_only, buf, 587 qflag) == -1) 588 ret = 1; 589 else 590 count++; 591 } 592 if (count == 0) 593 ret = 1; 594 } else { 595 for (i = 0; i < argc; i++) { 596 if (do_file(agent_fd, deleting, key_only, 597 argv[i], qflag) == -1) 598 ret = 1; 599 } 600 } 601 clear_pass(); 602 603 done: 604 ssh_close_authentication_socket(agent_fd); 605 return ret; 606 } 607