1 /* $OpenBSD: ssh-add.c,v 1.133 2017/07/01 13:50:45 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 <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) 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 fprintf(stderr, "Identity removed: %s (%s)\n", filename, comment); 109 ret = 0; 110 } else 111 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 112 filename, ssh_err(r)); 113 114 if (key_only) 115 goto out; 116 117 /* Now try to delete the corresponding certificate too */ 118 free(comment); 119 comment = NULL; 120 xasprintf(&certpath, "%s-cert.pub", filename); 121 if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) { 122 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 123 error("Failed to load certificate \"%s\": %s", 124 certpath, ssh_err(r)); 125 goto out; 126 } 127 128 if (!sshkey_equal_public(cert, public)) 129 fatal("Certificate %s does not match private key %s", 130 certpath, filename); 131 132 if ((r = ssh_remove_identity(agent_fd, cert)) == 0) { 133 fprintf(stderr, "Identity removed: %s (%s)\n", certpath, 134 comment); 135 ret = 0; 136 } else 137 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 138 certpath, ssh_err(r)); 139 140 out: 141 sshkey_free(cert); 142 sshkey_free(public); 143 free(certpath); 144 free(comment); 145 146 return ret; 147 } 148 149 /* Send a request to remove all identities. */ 150 static int 151 delete_all(int agent_fd) 152 { 153 int ret = -1; 154 155 /* 156 * Since the agent might be forwarded, old or non-OpenSSH, when asked 157 * to remove all keys, attempt to remove both protocol v.1 and v.2 158 * keys. 159 */ 160 if (ssh_remove_all_identities(agent_fd, 2) == 0) 161 ret = 0; 162 /* ignore error-code for ssh1 */ 163 ssh_remove_all_identities(agent_fd, 1); 164 165 if (ret == 0) 166 fprintf(stderr, "All identities removed.\n"); 167 else 168 fprintf(stderr, "Failed to remove all identities.\n"); 169 170 return ret; 171 } 172 173 static int 174 add_file(int agent_fd, const char *filename, int key_only) 175 { 176 struct sshkey *private, *cert; 177 char *comment = NULL; 178 char msg[1024], *certpath = NULL; 179 int r, fd, ret = -1; 180 struct sshbuf *keyblob; 181 182 if (strcmp(filename, "-") == 0) { 183 fd = STDIN_FILENO; 184 filename = "(stdin)"; 185 } else if ((fd = open(filename, O_RDONLY)) < 0) { 186 perror(filename); 187 return -1; 188 } 189 190 /* 191 * Since we'll try to load a keyfile multiple times, permission errors 192 * will occur multiple times, so check perms first and bail if wrong. 193 */ 194 if (fd != STDIN_FILENO) { 195 if (sshkey_perm_ok(fd, filename) != 0) { 196 close(fd); 197 return -1; 198 } 199 } 200 if ((keyblob = sshbuf_new()) == NULL) 201 fatal("%s: sshbuf_new failed", __func__); 202 if ((r = sshkey_load_file(fd, keyblob)) != 0) { 203 fprintf(stderr, "Error loading key \"%s\": %s\n", 204 filename, ssh_err(r)); 205 sshbuf_free(keyblob); 206 close(fd); 207 return -1; 208 } 209 close(fd); 210 211 /* At first, try empty passphrase */ 212 if ((r = sshkey_parse_private_fileblob(keyblob, "", &private, 213 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 214 fprintf(stderr, "Error loading key \"%s\": %s\n", 215 filename, ssh_err(r)); 216 goto fail_load; 217 } 218 /* try last */ 219 if (private == NULL && pass != NULL) { 220 if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private, 221 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 222 fprintf(stderr, "Error loading key \"%s\": %s\n", 223 filename, ssh_err(r)); 224 goto fail_load; 225 } 226 } 227 if (private == NULL) { 228 /* clear passphrase since it did not work */ 229 clear_pass(); 230 snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ", 231 filename, confirm ? " (will confirm each use)" : ""); 232 for (;;) { 233 pass = read_passphrase(msg, RP_ALLOW_STDIN); 234 if (strcmp(pass, "") == 0) 235 goto fail_load; 236 if ((r = sshkey_parse_private_fileblob(keyblob, pass, 237 &private, &comment)) == 0) 238 break; 239 else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 240 fprintf(stderr, 241 "Error loading key \"%s\": %s\n", 242 filename, ssh_err(r)); 243 fail_load: 244 clear_pass(); 245 sshbuf_free(keyblob); 246 return -1; 247 } 248 clear_pass(); 249 snprintf(msg, sizeof msg, 250 "Bad passphrase, try again for %s%s: ", filename, 251 confirm ? " (will confirm each use)" : ""); 252 } 253 } 254 if (comment == NULL || *comment == '\0') 255 comment = xstrdup(filename); 256 sshbuf_free(keyblob); 257 258 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 259 lifetime, confirm)) == 0) { 260 fprintf(stderr, "Identity added: %s (%s)\n", filename, comment); 261 ret = 0; 262 if (lifetime != 0) 263 fprintf(stderr, 264 "Lifetime set to %d seconds\n", lifetime); 265 if (confirm != 0) 266 fprintf(stderr, 267 "The user must confirm each use of the key\n"); 268 } else { 269 fprintf(stderr, "Could not add identity \"%s\": %s\n", 270 filename, ssh_err(r)); 271 } 272 273 /* Skip trying to load the cert if requested */ 274 if (key_only) 275 goto out; 276 277 /* Now try to add the certificate flavour too */ 278 xasprintf(&certpath, "%s-cert.pub", filename); 279 if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) { 280 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 281 error("Failed to load certificate \"%s\": %s", 282 certpath, ssh_err(r)); 283 goto out; 284 } 285 286 if (!sshkey_equal_public(cert, private)) { 287 error("Certificate %s does not match private key %s", 288 certpath, filename); 289 sshkey_free(cert); 290 goto out; 291 } 292 293 /* Graft with private bits */ 294 if ((r = sshkey_to_certified(private)) != 0) { 295 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r)); 296 sshkey_free(cert); 297 goto out; 298 } 299 if ((r = sshkey_cert_copy(cert, private)) != 0) { 300 error("%s: sshkey_cert_copy: %s", __func__, ssh_err(r)); 301 sshkey_free(cert); 302 goto out; 303 } 304 sshkey_free(cert); 305 306 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 307 lifetime, confirm)) != 0) { 308 error("Certificate %s (%s) add failed: %s", certpath, 309 private->cert->key_id, ssh_err(r)); 310 goto out; 311 } 312 fprintf(stderr, "Certificate added: %s (%s)\n", certpath, 313 private->cert->key_id); 314 if (lifetime != 0) 315 fprintf(stderr, "Lifetime set to %d seconds\n", lifetime); 316 if (confirm != 0) 317 fprintf(stderr, "The user must confirm each use of the key\n"); 318 out: 319 free(certpath); 320 free(comment); 321 sshkey_free(private); 322 323 return ret; 324 } 325 326 static int 327 update_card(int agent_fd, int add, const char *id) 328 { 329 char *pin = NULL; 330 int r, ret = -1; 331 332 if (add) { 333 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ", 334 RP_ALLOW_STDIN)) == NULL) 335 return -1; 336 } 337 338 if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin, 339 lifetime, confirm)) == 0) { 340 fprintf(stderr, "Card %s: %s\n", 341 add ? "added" : "removed", id); 342 ret = 0; 343 } else { 344 fprintf(stderr, "Could not %s card \"%s\": %s\n", 345 add ? "add" : "remove", id, ssh_err(r)); 346 ret = -1; 347 } 348 free(pin); 349 return ret; 350 } 351 352 static int 353 list_identities(int agent_fd, int do_fp) 354 { 355 char *fp; 356 int r; 357 struct ssh_identitylist *idlist; 358 size_t i; 359 360 if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 361 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 362 fprintf(stderr, "error fetching identities: %s\n", 363 ssh_err(r)); 364 else 365 printf("The agent has no identities.\n"); 366 return -1; 367 } 368 for (i = 0; i < idlist->nkeys; i++) { 369 if (do_fp) { 370 fp = sshkey_fingerprint(idlist->keys[i], 371 fingerprint_hash, SSH_FP_DEFAULT); 372 printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]), 373 fp == NULL ? "(null)" : fp, idlist->comments[i], 374 sshkey_type(idlist->keys[i])); 375 free(fp); 376 } else { 377 if ((r = sshkey_write(idlist->keys[i], stdout)) != 0) { 378 fprintf(stderr, "sshkey_write: %s\n", 379 ssh_err(r)); 380 continue; 381 } 382 fprintf(stdout, " %s\n", idlist->comments[i]); 383 } 384 } 385 ssh_free_identitylist(idlist); 386 return 0; 387 } 388 389 static int 390 lock_agent(int agent_fd, int lock) 391 { 392 char prompt[100], *p1, *p2; 393 int r, passok = 1, ret = -1; 394 395 strlcpy(prompt, "Enter lock password: ", sizeof(prompt)); 396 p1 = read_passphrase(prompt, RP_ALLOW_STDIN); 397 if (lock) { 398 strlcpy(prompt, "Again: ", sizeof prompt); 399 p2 = read_passphrase(prompt, RP_ALLOW_STDIN); 400 if (strcmp(p1, p2) != 0) { 401 fprintf(stderr, "Passwords do not match.\n"); 402 passok = 0; 403 } 404 explicit_bzero(p2, strlen(p2)); 405 free(p2); 406 } 407 if (passok) { 408 if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) { 409 fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un"); 410 ret = 0; 411 } else { 412 fprintf(stderr, "Failed to %slock agent: %s\n", 413 lock ? "" : "un", ssh_err(r)); 414 } 415 } 416 explicit_bzero(p1, strlen(p1)); 417 free(p1); 418 return (ret); 419 } 420 421 static int 422 do_file(int agent_fd, int deleting, int key_only, char *file) 423 { 424 if (deleting) { 425 if (delete_file(agent_fd, file, key_only) == -1) 426 return -1; 427 } else { 428 if (add_file(agent_fd, file, key_only) == -1) 429 return -1; 430 } 431 return 0; 432 } 433 434 static void 435 usage(void) 436 { 437 fprintf(stderr, "usage: %s [options] [file ...]\n", __progname); 438 fprintf(stderr, "Options:\n"); 439 fprintf(stderr, " -l List fingerprints of all identities.\n"); 440 fprintf(stderr, " -E hash Specify hash algorithm used for fingerprints.\n"); 441 fprintf(stderr, " -L List public key parameters of all identities.\n"); 442 fprintf(stderr, " -k Load only keys and not certificates.\n"); 443 fprintf(stderr, " -c Require confirmation to sign using identities\n"); 444 fprintf(stderr, " -t life Set lifetime (in seconds) when adding identities.\n"); 445 fprintf(stderr, " -d Delete identity.\n"); 446 fprintf(stderr, " -D Delete all identities.\n"); 447 fprintf(stderr, " -x Lock agent.\n"); 448 fprintf(stderr, " -X Unlock agent.\n"); 449 fprintf(stderr, " -s pkcs11 Add keys from PKCS#11 provider.\n"); 450 fprintf(stderr, " -e pkcs11 Remove keys provided by PKCS#11 provider.\n"); 451 } 452 453 int 454 main(int argc, char **argv) 455 { 456 extern char *optarg; 457 extern int optind; 458 int agent_fd; 459 char *pkcs11provider = NULL; 460 int r, i, ch, deleting = 0, ret = 0, key_only = 0; 461 int xflag = 0, lflag = 0, Dflag = 0; 462 463 ssh_malloc_init(); /* must be called before any mallocs */ 464 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 465 sanitise_stdfd(); 466 467 OpenSSL_add_all_algorithms(); 468 469 setvbuf(stdout, NULL, _IOLBF, 0); 470 471 /* First, get a connection to the authentication agent. */ 472 switch (r = ssh_get_authentication_socket(&agent_fd)) { 473 case 0: 474 break; 475 case SSH_ERR_AGENT_NOT_PRESENT: 476 fprintf(stderr, "Could not open a connection to your " 477 "authentication agent.\n"); 478 exit(2); 479 default: 480 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r)); 481 exit(2); 482 } 483 484 while ((ch = getopt(argc, argv, "klLcdDxXE:e:s:t:")) != -1) { 485 switch (ch) { 486 case 'E': 487 fingerprint_hash = ssh_digest_alg_by_name(optarg); 488 if (fingerprint_hash == -1) 489 fatal("Invalid hash algorithm \"%s\"", optarg); 490 break; 491 case 'k': 492 key_only = 1; 493 break; 494 case 'l': 495 case 'L': 496 if (lflag != 0) 497 fatal("-%c flag already specified", lflag); 498 lflag = ch; 499 break; 500 case 'x': 501 case 'X': 502 if (xflag != 0) 503 fatal("-%c flag already specified", xflag); 504 xflag = ch; 505 break; 506 case 'c': 507 confirm = 1; 508 break; 509 case 'd': 510 deleting = 1; 511 break; 512 case 'D': 513 Dflag = 1; 514 break; 515 case 's': 516 pkcs11provider = optarg; 517 break; 518 case 'e': 519 deleting = 1; 520 pkcs11provider = optarg; 521 break; 522 case 't': 523 if ((lifetime = convtime(optarg)) == -1) { 524 fprintf(stderr, "Invalid lifetime\n"); 525 ret = 1; 526 goto done; 527 } 528 break; 529 default: 530 usage(); 531 ret = 1; 532 goto done; 533 } 534 } 535 536 if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1) 537 fatal("Invalid combination of actions"); 538 else if (xflag) { 539 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1) 540 ret = 1; 541 goto done; 542 } else if (lflag) { 543 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1) 544 ret = 1; 545 goto done; 546 } else if (Dflag) { 547 if (delete_all(agent_fd) == -1) 548 ret = 1; 549 goto done; 550 } 551 552 argc -= optind; 553 argv += optind; 554 if (pkcs11provider != NULL) { 555 if (update_card(agent_fd, !deleting, pkcs11provider) == -1) 556 ret = 1; 557 goto done; 558 } 559 if (argc == 0) { 560 char buf[PATH_MAX]; 561 struct passwd *pw; 562 struct stat st; 563 int count = 0; 564 565 if ((pw = getpwuid(getuid())) == NULL) { 566 fprintf(stderr, "No user found with uid %u\n", 567 (u_int)getuid()); 568 ret = 1; 569 goto done; 570 } 571 572 for (i = 0; default_files[i]; i++) { 573 snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, 574 default_files[i]); 575 if (stat(buf, &st) < 0) 576 continue; 577 if (do_file(agent_fd, deleting, key_only, buf) == -1) 578 ret = 1; 579 else 580 count++; 581 } 582 if (count == 0) 583 ret = 1; 584 } else { 585 for (i = 0; i < argc; i++) { 586 if (do_file(agent_fd, deleting, key_only, 587 argv[i]) == -1) 588 ret = 1; 589 } 590 } 591 clear_pass(); 592 593 done: 594 ssh_close_authentication_socket(agent_fd); 595 return ret; 596 } 597