1 /* $OpenBSD: ssh-add.c,v 1.132 2017/05/30 14:16:41 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 <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 NULL 75 }; 76 77 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 78 79 /* Default lifetime (0 == forever) */ 80 static int lifetime = 0; 81 82 /* User has to confirm key use */ 83 static int confirm = 0; 84 85 /* we keep a cache of one passphrase */ 86 static char *pass = NULL; 87 static void 88 clear_pass(void) 89 { 90 if (pass) { 91 explicit_bzero(pass, strlen(pass)); 92 free(pass); 93 pass = NULL; 94 } 95 } 96 97 static int 98 delete_file(int agent_fd, const char *filename, int key_only) 99 { 100 struct sshkey *public, *cert = NULL; 101 char *certpath = NULL, *comment = NULL; 102 int r, ret = -1; 103 104 if ((r = sshkey_load_public(filename, &public, &comment)) != 0) { 105 printf("Bad key file %s: %s\n", filename, ssh_err(r)); 106 return -1; 107 } 108 if ((r = ssh_remove_identity(agent_fd, public)) == 0) { 109 fprintf(stderr, "Identity removed: %s (%s)\n", filename, comment); 110 ret = 0; 111 } else 112 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 113 filename, ssh_err(r)); 114 115 if (key_only) 116 goto out; 117 118 /* Now try to delete the corresponding certificate too */ 119 free(comment); 120 comment = NULL; 121 xasprintf(&certpath, "%s-cert.pub", filename); 122 if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) { 123 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 124 error("Failed to load certificate \"%s\": %s", 125 certpath, ssh_err(r)); 126 goto out; 127 } 128 129 if (!sshkey_equal_public(cert, public)) 130 fatal("Certificate %s does not match private key %s", 131 certpath, filename); 132 133 if ((r = ssh_remove_identity(agent_fd, cert)) == 0) { 134 fprintf(stderr, "Identity removed: %s (%s)\n", certpath, 135 comment); 136 ret = 0; 137 } else 138 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 139 certpath, ssh_err(r)); 140 141 out: 142 sshkey_free(cert); 143 sshkey_free(public); 144 free(certpath); 145 free(comment); 146 147 return ret; 148 } 149 150 /* Send a request to remove all identities. */ 151 static int 152 delete_all(int agent_fd) 153 { 154 int ret = -1; 155 156 /* 157 * Since the agent might be forwarded, old or non-OpenSSH, when asked 158 * to remove all keys, attempt to remove both protocol v.1 and v.2 159 * keys. 160 */ 161 if (ssh_remove_all_identities(agent_fd, 2) == 0) 162 ret = 0; 163 /* ignore error-code for ssh1 */ 164 ssh_remove_all_identities(agent_fd, 1); 165 166 if (ret == 0) 167 fprintf(stderr, "All identities removed.\n"); 168 else 169 fprintf(stderr, "Failed to remove all identities.\n"); 170 171 return ret; 172 } 173 174 static int 175 add_file(int agent_fd, const char *filename, int key_only) 176 { 177 struct sshkey *private, *cert; 178 char *comment = NULL; 179 char msg[1024], *certpath = NULL; 180 int r, fd, ret = -1; 181 struct sshbuf *keyblob; 182 183 if (strcmp(filename, "-") == 0) { 184 fd = STDIN_FILENO; 185 filename = "(stdin)"; 186 } else if ((fd = open(filename, O_RDONLY)) < 0) { 187 perror(filename); 188 return -1; 189 } 190 191 /* 192 * Since we'll try to load a keyfile multiple times, permission errors 193 * will occur multiple times, so check perms first and bail if wrong. 194 */ 195 if (fd != STDIN_FILENO) { 196 if (sshkey_perm_ok(fd, filename) != 0) { 197 close(fd); 198 return -1; 199 } 200 } 201 if ((keyblob = sshbuf_new()) == NULL) 202 fatal("%s: sshbuf_new failed", __func__); 203 if ((r = sshkey_load_file(fd, keyblob)) != 0) { 204 fprintf(stderr, "Error loading key \"%s\": %s\n", 205 filename, ssh_err(r)); 206 sshbuf_free(keyblob); 207 close(fd); 208 return -1; 209 } 210 close(fd); 211 212 /* At first, try empty passphrase */ 213 if ((r = sshkey_parse_private_fileblob(keyblob, "", &private, 214 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 215 fprintf(stderr, "Error loading key \"%s\": %s\n", 216 filename, ssh_err(r)); 217 goto fail_load; 218 } 219 /* try last */ 220 if (private == NULL && pass != NULL) { 221 if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private, 222 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 223 fprintf(stderr, "Error loading key \"%s\": %s\n", 224 filename, ssh_err(r)); 225 goto fail_load; 226 } 227 } 228 if (private == NULL) { 229 /* clear passphrase since it did not work */ 230 clear_pass(); 231 snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ", 232 filename, confirm ? " (will confirm each use)" : ""); 233 for (;;) { 234 pass = read_passphrase(msg, RP_ALLOW_STDIN); 235 if (strcmp(pass, "") == 0) 236 goto fail_load; 237 if ((r = sshkey_parse_private_fileblob(keyblob, pass, 238 &private, &comment)) == 0) 239 break; 240 else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 241 fprintf(stderr, 242 "Error loading key \"%s\": %s\n", 243 filename, ssh_err(r)); 244 fail_load: 245 clear_pass(); 246 sshbuf_free(keyblob); 247 return -1; 248 } 249 clear_pass(); 250 snprintf(msg, sizeof msg, 251 "Bad passphrase, try again for %s%s: ", filename, 252 confirm ? " (will confirm each use)" : ""); 253 } 254 } 255 if (comment == NULL || *comment == '\0') 256 comment = xstrdup(filename); 257 sshbuf_free(keyblob); 258 259 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 260 lifetime, confirm)) == 0) { 261 fprintf(stderr, "Identity added: %s (%s)\n", filename, comment); 262 ret = 0; 263 if (lifetime != 0) 264 fprintf(stderr, 265 "Lifetime set to %d seconds\n", lifetime); 266 if (confirm != 0) 267 fprintf(stderr, 268 "The user must confirm each use of the key\n"); 269 } else { 270 fprintf(stderr, "Could not add identity \"%s\": %s\n", 271 filename, ssh_err(r)); 272 } 273 274 /* Skip trying to load the cert if requested */ 275 if (key_only) 276 goto out; 277 278 /* Now try to add the certificate flavour too */ 279 xasprintf(&certpath, "%s-cert.pub", filename); 280 if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) { 281 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 282 error("Failed to load certificate \"%s\": %s", 283 certpath, ssh_err(r)); 284 goto out; 285 } 286 287 if (!sshkey_equal_public(cert, private)) { 288 error("Certificate %s does not match private key %s", 289 certpath, filename); 290 sshkey_free(cert); 291 goto out; 292 } 293 294 /* Graft with private bits */ 295 if ((r = sshkey_to_certified(private)) != 0) { 296 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r)); 297 sshkey_free(cert); 298 goto out; 299 } 300 if ((r = sshkey_cert_copy(cert, private)) != 0) { 301 error("%s: sshkey_cert_copy: %s", __func__, ssh_err(r)); 302 sshkey_free(cert); 303 goto out; 304 } 305 sshkey_free(cert); 306 307 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 308 lifetime, confirm)) != 0) { 309 error("Certificate %s (%s) add failed: %s", certpath, 310 private->cert->key_id, ssh_err(r)); 311 goto out; 312 } 313 fprintf(stderr, "Certificate added: %s (%s)\n", certpath, 314 private->cert->key_id); 315 if (lifetime != 0) 316 fprintf(stderr, "Lifetime set to %d seconds\n", lifetime); 317 if (confirm != 0) 318 fprintf(stderr, "The user must confirm each use of the key\n"); 319 out: 320 free(certpath); 321 free(comment); 322 sshkey_free(private); 323 324 return ret; 325 } 326 327 static int 328 update_card(int agent_fd, int add, const char *id) 329 { 330 char *pin = NULL; 331 int r, ret = -1; 332 333 if (add) { 334 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ", 335 RP_ALLOW_STDIN)) == NULL) 336 return -1; 337 } 338 339 if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin, 340 lifetime, confirm)) == 0) { 341 fprintf(stderr, "Card %s: %s\n", 342 add ? "added" : "removed", id); 343 ret = 0; 344 } else { 345 fprintf(stderr, "Could not %s card \"%s\": %s\n", 346 add ? "add" : "remove", id, ssh_err(r)); 347 ret = -1; 348 } 349 free(pin); 350 return ret; 351 } 352 353 static int 354 list_identities(int agent_fd, int do_fp) 355 { 356 char *fp; 357 int r; 358 struct ssh_identitylist *idlist; 359 size_t i; 360 361 if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 362 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 363 fprintf(stderr, "error fetching identities: %s\n", 364 ssh_err(r)); 365 else 366 printf("The agent has no identities.\n"); 367 return -1; 368 } 369 for (i = 0; i < idlist->nkeys; i++) { 370 if (do_fp) { 371 fp = sshkey_fingerprint(idlist->keys[i], 372 fingerprint_hash, SSH_FP_DEFAULT); 373 printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]), 374 fp == NULL ? "(null)" : fp, idlist->comments[i], 375 sshkey_type(idlist->keys[i])); 376 free(fp); 377 } else { 378 if ((r = sshkey_write(idlist->keys[i], stdout)) != 0) { 379 fprintf(stderr, "sshkey_write: %s\n", 380 ssh_err(r)); 381 continue; 382 } 383 fprintf(stdout, " %s\n", idlist->comments[i]); 384 } 385 } 386 ssh_free_identitylist(idlist); 387 return 0; 388 } 389 390 static int 391 lock_agent(int agent_fd, int lock) 392 { 393 char prompt[100], *p1, *p2; 394 int r, passok = 1, ret = -1; 395 396 strlcpy(prompt, "Enter lock password: ", sizeof(prompt)); 397 p1 = read_passphrase(prompt, RP_ALLOW_STDIN); 398 if (lock) { 399 strlcpy(prompt, "Again: ", sizeof prompt); 400 p2 = read_passphrase(prompt, RP_ALLOW_STDIN); 401 if (strcmp(p1, p2) != 0) { 402 fprintf(stderr, "Passwords do not match.\n"); 403 passok = 0; 404 } 405 explicit_bzero(p2, strlen(p2)); 406 free(p2); 407 } 408 if (passok) { 409 if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) { 410 fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un"); 411 ret = 0; 412 } else { 413 fprintf(stderr, "Failed to %slock agent: %s\n", 414 lock ? "" : "un", ssh_err(r)); 415 } 416 } 417 explicit_bzero(p1, strlen(p1)); 418 free(p1); 419 return (ret); 420 } 421 422 static int 423 do_file(int agent_fd, int deleting, int key_only, char *file) 424 { 425 if (deleting) { 426 if (delete_file(agent_fd, file, key_only) == -1) 427 return -1; 428 } else { 429 if (add_file(agent_fd, file, key_only) == -1) 430 return -1; 431 } 432 return 0; 433 } 434 435 static void 436 usage(void) 437 { 438 fprintf(stderr, "usage: %s [options] [file ...]\n", __progname); 439 fprintf(stderr, "Options:\n"); 440 fprintf(stderr, " -l List fingerprints of all identities.\n"); 441 fprintf(stderr, " -E hash Specify hash algorithm used for fingerprints.\n"); 442 fprintf(stderr, " -L List public key parameters of all identities.\n"); 443 fprintf(stderr, " -k Load only keys and not certificates.\n"); 444 fprintf(stderr, " -c Require confirmation to sign using identities\n"); 445 fprintf(stderr, " -t life Set lifetime (in seconds) when adding identities.\n"); 446 fprintf(stderr, " -d Delete identity.\n"); 447 fprintf(stderr, " -D Delete all identities.\n"); 448 fprintf(stderr, " -x Lock agent.\n"); 449 fprintf(stderr, " -X Unlock agent.\n"); 450 fprintf(stderr, " -s pkcs11 Add keys from PKCS#11 provider.\n"); 451 fprintf(stderr, " -e pkcs11 Remove keys provided by PKCS#11 provider.\n"); 452 } 453 454 int 455 main(int argc, char **argv) 456 { 457 extern char *optarg; 458 extern int optind; 459 int agent_fd; 460 char *pkcs11provider = NULL; 461 int r, i, ch, deleting = 0, ret = 0, key_only = 0; 462 int xflag = 0, lflag = 0, Dflag = 0; 463 464 ssh_malloc_init(); /* must be called before any mallocs */ 465 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 466 sanitise_stdfd(); 467 468 OpenSSL_add_all_algorithms(); 469 470 setvbuf(stdout, NULL, _IOLBF, 0); 471 472 /* First, get a connection to the authentication agent. */ 473 switch (r = ssh_get_authentication_socket(&agent_fd)) { 474 case 0: 475 break; 476 case SSH_ERR_AGENT_NOT_PRESENT: 477 fprintf(stderr, "Could not open a connection to your " 478 "authentication agent.\n"); 479 exit(2); 480 default: 481 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r)); 482 exit(2); 483 } 484 485 while ((ch = getopt(argc, argv, "klLcdDxXE:e:s:t:")) != -1) { 486 switch (ch) { 487 case 'E': 488 fingerprint_hash = ssh_digest_alg_by_name(optarg); 489 if (fingerprint_hash == -1) 490 fatal("Invalid hash algorithm \"%s\"", optarg); 491 break; 492 case 'k': 493 key_only = 1; 494 break; 495 case 'l': 496 case 'L': 497 if (lflag != 0) 498 fatal("-%c flag already specified", lflag); 499 lflag = ch; 500 break; 501 case 'x': 502 case 'X': 503 if (xflag != 0) 504 fatal("-%c flag already specified", xflag); 505 xflag = ch; 506 break; 507 case 'c': 508 confirm = 1; 509 break; 510 case 'd': 511 deleting = 1; 512 break; 513 case 'D': 514 Dflag = 1; 515 break; 516 case 's': 517 pkcs11provider = optarg; 518 break; 519 case 'e': 520 deleting = 1; 521 pkcs11provider = optarg; 522 break; 523 case 't': 524 if ((lifetime = convtime(optarg)) == -1) { 525 fprintf(stderr, "Invalid lifetime\n"); 526 ret = 1; 527 goto done; 528 } 529 break; 530 default: 531 usage(); 532 ret = 1; 533 goto done; 534 } 535 } 536 537 if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1) 538 fatal("Invalid combination of actions"); 539 else if (xflag) { 540 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1) 541 ret = 1; 542 goto done; 543 } else if (lflag) { 544 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1) 545 ret = 1; 546 goto done; 547 } else if (Dflag) { 548 if (delete_all(agent_fd) == -1) 549 ret = 1; 550 goto done; 551 } 552 553 argc -= optind; 554 argv += optind; 555 if (pkcs11provider != NULL) { 556 if (update_card(agent_fd, !deleting, pkcs11provider) == -1) 557 ret = 1; 558 goto done; 559 } 560 if (argc == 0) { 561 char buf[PATH_MAX]; 562 struct passwd *pw; 563 struct stat st; 564 int count = 0; 565 566 if ((pw = getpwuid(getuid())) == NULL) { 567 fprintf(stderr, "No user found with uid %u\n", 568 (u_int)getuid()); 569 ret = 1; 570 goto done; 571 } 572 573 for (i = 0; default_files[i]; i++) { 574 snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, 575 default_files[i]); 576 if (stat(buf, &st) < 0) 577 continue; 578 if (do_file(agent_fd, deleting, key_only, buf) == -1) 579 ret = 1; 580 else 581 count++; 582 } 583 if (count == 0) 584 ret = 1; 585 } else { 586 for (i = 0; i < argc; i++) { 587 if (do_file(agent_fd, deleting, key_only, 588 argv[i]) == -1) 589 ret = 1; 590 } 591 } 592 clear_pass(); 593 594 done: 595 ssh_close_authentication_socket(agent_fd); 596 return ret; 597 } 598