1 /* $OpenBSD: ssh-add.c,v 1.128 2016/02/15 09:47:49 dtucker 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 "rsa.h" 55 #include "log.h" 56 #include "sshkey.h" 57 #include "sshbuf.h" 58 #include "authfd.h" 59 #include "authfile.h" 60 #include "pathnames.h" 61 #include "misc.h" 62 #include "ssherr.h" 63 #include "digest.h" 64 65 /* argv0 */ 66 extern char *__progname; 67 68 /* Default files to add */ 69 static char *default_files[] = { 70 _PATH_SSH_CLIENT_ID_RSA, 71 _PATH_SSH_CLIENT_ID_DSA, 72 _PATH_SSH_CLIENT_ID_ECDSA, 73 _PATH_SSH_CLIENT_ID_ED25519, 74 #ifdef WITH_SSH1 75 _PATH_SSH_CLIENT_IDENTITY, 76 #endif 77 NULL 78 }; 79 80 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 81 82 /* Default lifetime (0 == forever) */ 83 static int lifetime = 0; 84 85 /* User has to confirm key use */ 86 static int confirm = 0; 87 88 /* we keep a cache of one passphrase */ 89 static char *pass = NULL; 90 static void 91 clear_pass(void) 92 { 93 if (pass) { 94 explicit_bzero(pass, strlen(pass)); 95 free(pass); 96 pass = NULL; 97 } 98 } 99 100 static int 101 delete_file(int agent_fd, const char *filename, int key_only) 102 { 103 struct sshkey *public, *cert = NULL; 104 char *certpath = NULL, *comment = NULL; 105 int r, ret = -1; 106 107 if ((r = sshkey_load_public(filename, &public, &comment)) != 0) { 108 printf("Bad key file %s: %s\n", filename, ssh_err(r)); 109 return -1; 110 } 111 if ((r = ssh_remove_identity(agent_fd, public)) == 0) { 112 fprintf(stderr, "Identity removed: %s (%s)\n", filename, comment); 113 ret = 0; 114 } else 115 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 116 filename, ssh_err(r)); 117 118 if (key_only) 119 goto out; 120 121 /* Now try to delete the corresponding certificate too */ 122 free(comment); 123 comment = NULL; 124 xasprintf(&certpath, "%s-cert.pub", filename); 125 if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) { 126 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 127 error("Failed to load certificate \"%s\": %s", 128 certpath, ssh_err(r)); 129 goto out; 130 } 131 132 if (!sshkey_equal_public(cert, public)) 133 fatal("Certificate %s does not match private key %s", 134 certpath, filename); 135 136 if ((r = ssh_remove_identity(agent_fd, cert)) == 0) { 137 fprintf(stderr, "Identity removed: %s (%s)\n", certpath, 138 comment); 139 ret = 0; 140 } else 141 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 142 certpath, ssh_err(r)); 143 144 out: 145 sshkey_free(cert); 146 sshkey_free(public); 147 free(certpath); 148 free(comment); 149 150 return ret; 151 } 152 153 /* Send a request to remove all identities. */ 154 static int 155 delete_all(int agent_fd) 156 { 157 int ret = -1; 158 159 if (ssh_remove_all_identities(agent_fd, 2) == 0) 160 ret = 0; 161 /* ignore error-code for ssh1 */ 162 ssh_remove_all_identities(agent_fd, 1); 163 164 if (ret == 0) 165 fprintf(stderr, "All identities removed.\n"); 166 else 167 fprintf(stderr, "Failed to remove all identities.\n"); 168 169 return ret; 170 } 171 172 static int 173 add_file(int agent_fd, const char *filename, int key_only) 174 { 175 struct sshkey *private, *cert; 176 char *comment = NULL; 177 char msg[1024], *certpath = NULL; 178 int r, fd, ret = -1; 179 struct sshbuf *keyblob; 180 181 if (strcmp(filename, "-") == 0) { 182 fd = STDIN_FILENO; 183 filename = "(stdin)"; 184 } else if ((fd = open(filename, O_RDONLY)) < 0) { 185 perror(filename); 186 return -1; 187 } 188 189 /* 190 * Since we'll try to load a keyfile multiple times, permission errors 191 * will occur multiple times, so check perms first and bail if wrong. 192 */ 193 if (fd != STDIN_FILENO) { 194 if (sshkey_perm_ok(fd, filename) != 0) { 195 close(fd); 196 return -1; 197 } 198 } 199 if ((keyblob = sshbuf_new()) == NULL) 200 fatal("%s: sshbuf_new failed", __func__); 201 if ((r = sshkey_load_file(fd, keyblob)) != 0) { 202 fprintf(stderr, "Error loading key \"%s\": %s\n", 203 filename, ssh_err(r)); 204 sshbuf_free(keyblob); 205 close(fd); 206 return -1; 207 } 208 close(fd); 209 210 /* At first, try empty passphrase */ 211 if ((r = sshkey_parse_private_fileblob(keyblob, "", &private, 212 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 213 fprintf(stderr, "Error loading key \"%s\": %s\n", 214 filename, ssh_err(r)); 215 goto fail_load; 216 } 217 /* try last */ 218 if (private == NULL && pass != NULL) { 219 if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private, 220 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 221 fprintf(stderr, "Error loading key \"%s\": %s\n", 222 filename, ssh_err(r)); 223 goto fail_load; 224 } 225 } 226 if (private == NULL) { 227 /* clear passphrase since it did not work */ 228 clear_pass(); 229 snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ", 230 filename, confirm ? " (will confirm each use)" : ""); 231 for (;;) { 232 pass = read_passphrase(msg, RP_ALLOW_STDIN); 233 if (strcmp(pass, "") == 0) 234 goto fail_load; 235 if ((r = sshkey_parse_private_fileblob(keyblob, pass, 236 &private, &comment)) == 0) 237 break; 238 else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 239 fprintf(stderr, 240 "Error loading key \"%s\": %s\n", 241 filename, ssh_err(r)); 242 fail_load: 243 clear_pass(); 244 sshbuf_free(keyblob); 245 return -1; 246 } 247 clear_pass(); 248 snprintf(msg, sizeof msg, 249 "Bad passphrase, try again for %s%s: ", filename, 250 confirm ? " (will confirm each use)" : ""); 251 } 252 } 253 if (comment == NULL || *comment == '\0') 254 comment = xstrdup(filename); 255 sshbuf_free(keyblob); 256 257 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 258 lifetime, confirm)) == 0) { 259 fprintf(stderr, "Identity added: %s (%s)\n", filename, comment); 260 ret = 0; 261 if (lifetime != 0) 262 fprintf(stderr, 263 "Lifetime set to %d seconds\n", lifetime); 264 if (confirm != 0) 265 fprintf(stderr, 266 "The user must confirm each use of the key\n"); 267 } else { 268 fprintf(stderr, "Could not add identity \"%s\": %s\n", 269 filename, ssh_err(r)); 270 } 271 272 /* Skip trying to load the cert if requested */ 273 if (key_only) 274 goto out; 275 276 /* Now try to add the certificate flavour too */ 277 xasprintf(&certpath, "%s-cert.pub", filename); 278 if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) { 279 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 280 error("Failed to load certificate \"%s\": %s", 281 certpath, ssh_err(r)); 282 goto out; 283 } 284 285 if (!sshkey_equal_public(cert, private)) { 286 error("Certificate %s does not match private key %s", 287 certpath, filename); 288 sshkey_free(cert); 289 goto out; 290 } 291 292 /* Graft with private bits */ 293 if ((r = sshkey_to_certified(private)) != 0) { 294 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r)); 295 sshkey_free(cert); 296 goto out; 297 } 298 if ((r = sshkey_cert_copy(cert, private)) != 0) { 299 error("%s: key_cert_copy: %s", __func__, ssh_err(r)); 300 sshkey_free(cert); 301 goto out; 302 } 303 sshkey_free(cert); 304 305 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 306 lifetime, confirm)) != 0) { 307 error("Certificate %s (%s) add failed: %s", certpath, 308 private->cert->key_id, ssh_err(r)); 309 goto out; 310 } 311 fprintf(stderr, "Certificate added: %s (%s)\n", certpath, 312 private->cert->key_id); 313 if (lifetime != 0) 314 fprintf(stderr, "Lifetime set to %d seconds\n", lifetime); 315 if (confirm != 0) 316 fprintf(stderr, "The user must confirm each use of the key\n"); 317 out: 318 free(certpath); 319 free(comment); 320 sshkey_free(private); 321 322 return ret; 323 } 324 325 static int 326 update_card(int agent_fd, int add, const char *id) 327 { 328 char *pin = NULL; 329 int r, ret = -1; 330 331 if (add) { 332 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ", 333 RP_ALLOW_STDIN)) == NULL) 334 return -1; 335 } 336 337 if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin, 338 lifetime, confirm)) == 0) { 339 fprintf(stderr, "Card %s: %s\n", 340 add ? "added" : "removed", id); 341 ret = 0; 342 } else { 343 fprintf(stderr, "Could not %s card \"%s\": %s\n", 344 add ? "add" : "remove", id, ssh_err(r)); 345 ret = -1; 346 } 347 free(pin); 348 return ret; 349 } 350 351 static int 352 list_identities(int agent_fd, int do_fp) 353 { 354 char *fp; 355 int r, had_identities = 0; 356 struct ssh_identitylist *idlist; 357 size_t i; 358 #ifdef WITH_SSH1 359 int version = 1; 360 #else 361 int version = 2; 362 #endif 363 364 for (; version <= 2; version++) { 365 if ((r = ssh_fetch_identitylist(agent_fd, version, 366 &idlist)) != 0) { 367 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 368 fprintf(stderr, "error fetching identities for " 369 "protocol %d: %s\n", version, ssh_err(r)); 370 continue; 371 } 372 for (i = 0; i < idlist->nkeys; i++) { 373 had_identities = 1; 374 if (do_fp) { 375 fp = sshkey_fingerprint(idlist->keys[i], 376 fingerprint_hash, SSH_FP_DEFAULT); 377 printf("%u %s %s (%s)\n", 378 sshkey_size(idlist->keys[i]), 379 fp == NULL ? "(null)" : fp, 380 idlist->comments[i], 381 sshkey_type(idlist->keys[i])); 382 free(fp); 383 } else { 384 if ((r = sshkey_write(idlist->keys[i], 385 stdout)) != 0) { 386 fprintf(stderr, "sshkey_write: %s\n", 387 ssh_err(r)); 388 continue; 389 } 390 fprintf(stdout, " %s\n", idlist->comments[i]); 391 } 392 } 393 ssh_free_identitylist(idlist); 394 } 395 if (!had_identities) { 396 printf("The agent has no identities.\n"); 397 return -1; 398 } 399 return 0; 400 } 401 402 static int 403 lock_agent(int agent_fd, int lock) 404 { 405 char prompt[100], *p1, *p2; 406 int r, passok = 1, ret = -1; 407 408 strlcpy(prompt, "Enter lock password: ", sizeof(prompt)); 409 p1 = read_passphrase(prompt, RP_ALLOW_STDIN); 410 if (lock) { 411 strlcpy(prompt, "Again: ", sizeof prompt); 412 p2 = read_passphrase(prompt, RP_ALLOW_STDIN); 413 if (strcmp(p1, p2) != 0) { 414 fprintf(stderr, "Passwords do not match.\n"); 415 passok = 0; 416 } 417 explicit_bzero(p2, strlen(p2)); 418 free(p2); 419 } 420 if (passok) { 421 if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) { 422 fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un"); 423 ret = 0; 424 } else { 425 fprintf(stderr, "Failed to %slock agent: %s\n", 426 lock ? "" : "un", ssh_err(r)); 427 } 428 } 429 explicit_bzero(p1, strlen(p1)); 430 free(p1); 431 return (ret); 432 } 433 434 static int 435 do_file(int agent_fd, int deleting, int key_only, char *file) 436 { 437 if (deleting) { 438 if (delete_file(agent_fd, file, key_only) == -1) 439 return -1; 440 } else { 441 if (add_file(agent_fd, file, key_only) == -1) 442 return -1; 443 } 444 return 0; 445 } 446 447 static void 448 usage(void) 449 { 450 fprintf(stderr, "usage: %s [options] [file ...]\n", __progname); 451 fprintf(stderr, "Options:\n"); 452 fprintf(stderr, " -l List fingerprints of all identities.\n"); 453 fprintf(stderr, " -E hash Specify hash algorithm used for fingerprints.\n"); 454 fprintf(stderr, " -L List public key parameters of all identities.\n"); 455 fprintf(stderr, " -k Load only keys and not certificates.\n"); 456 fprintf(stderr, " -c Require confirmation to sign using identities\n"); 457 fprintf(stderr, " -t life Set lifetime (in seconds) when adding identities.\n"); 458 fprintf(stderr, " -d Delete identity.\n"); 459 fprintf(stderr, " -D Delete all identities.\n"); 460 fprintf(stderr, " -x Lock agent.\n"); 461 fprintf(stderr, " -X Unlock agent.\n"); 462 fprintf(stderr, " -s pkcs11 Add keys from PKCS#11 provider.\n"); 463 fprintf(stderr, " -e pkcs11 Remove keys provided by PKCS#11 provider.\n"); 464 } 465 466 int 467 main(int argc, char **argv) 468 { 469 extern char *optarg; 470 extern int optind; 471 int agent_fd; 472 char *pkcs11provider = NULL; 473 int r, i, ch, deleting = 0, ret = 0, key_only = 0; 474 int xflag = 0, lflag = 0, Dflag = 0; 475 476 ssh_malloc_init(); /* must be called before any mallocs */ 477 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 478 sanitise_stdfd(); 479 480 OpenSSL_add_all_algorithms(); 481 482 setvbuf(stdout, NULL, _IOLBF, 0); 483 484 /* First, get a connection to the authentication agent. */ 485 switch (r = ssh_get_authentication_socket(&agent_fd)) { 486 case 0: 487 break; 488 case SSH_ERR_AGENT_NOT_PRESENT: 489 fprintf(stderr, "Could not open a connection to your " 490 "authentication agent.\n"); 491 exit(2); 492 default: 493 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r)); 494 exit(2); 495 } 496 497 while ((ch = getopt(argc, argv, "klLcdDxXE:e:s:t:")) != -1) { 498 switch (ch) { 499 case 'E': 500 fingerprint_hash = ssh_digest_alg_by_name(optarg); 501 if (fingerprint_hash == -1) 502 fatal("Invalid hash algorithm \"%s\"", optarg); 503 break; 504 case 'k': 505 key_only = 1; 506 break; 507 case 'l': 508 case 'L': 509 if (lflag != 0) 510 fatal("-%c flag already specified", lflag); 511 lflag = ch; 512 break; 513 case 'x': 514 case 'X': 515 if (xflag != 0) 516 fatal("-%c flag already specified", xflag); 517 xflag = ch; 518 break; 519 case 'c': 520 confirm = 1; 521 break; 522 case 'd': 523 deleting = 1; 524 break; 525 case 'D': 526 Dflag = 1; 527 break; 528 case 's': 529 pkcs11provider = optarg; 530 break; 531 case 'e': 532 deleting = 1; 533 pkcs11provider = optarg; 534 break; 535 case 't': 536 if ((lifetime = convtime(optarg)) == -1) { 537 fprintf(stderr, "Invalid lifetime\n"); 538 ret = 1; 539 goto done; 540 } 541 break; 542 default: 543 usage(); 544 ret = 1; 545 goto done; 546 } 547 } 548 549 if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1) 550 fatal("Invalid combination of actions"); 551 else if (xflag) { 552 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1) 553 ret = 1; 554 goto done; 555 } else if (lflag) { 556 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1) 557 ret = 1; 558 goto done; 559 } else if (Dflag) { 560 if (delete_all(agent_fd) == -1) 561 ret = 1; 562 goto done; 563 } 564 565 argc -= optind; 566 argv += optind; 567 if (pkcs11provider != NULL) { 568 if (update_card(agent_fd, !deleting, pkcs11provider) == -1) 569 ret = 1; 570 goto done; 571 } 572 if (argc == 0) { 573 char buf[PATH_MAX]; 574 struct passwd *pw; 575 struct stat st; 576 int count = 0; 577 578 if ((pw = getpwuid(getuid())) == NULL) { 579 fprintf(stderr, "No user found with uid %u\n", 580 (u_int)getuid()); 581 ret = 1; 582 goto done; 583 } 584 585 for (i = 0; default_files[i]; i++) { 586 snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, 587 default_files[i]); 588 if (stat(buf, &st) < 0) 589 continue; 590 if (do_file(agent_fd, deleting, key_only, buf) == -1) 591 ret = 1; 592 else 593 count++; 594 } 595 if (count == 0) 596 ret = 1; 597 } else { 598 for (i = 0; i < argc; i++) { 599 if (do_file(agent_fd, deleting, key_only, 600 argv[i]) == -1) 601 ret = 1; 602 } 603 } 604 clear_pass(); 605 606 done: 607 ssh_close_authentication_socket(agent_fd); 608 return ret; 609 } 610