1 /* $NetBSD: ssh-add.c,v 1.16 2017/10/07 19:39:19 christos Exp $ */ 2 /* $OpenBSD: ssh-add.c,v 1.134 2017/08/29 09:42:29 dlg Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * Adds an identity to the authentication server, or removes an identity. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * SSH2 implementation, 16 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 #include "includes.h" 40 __RCSID("$NetBSD: ssh-add.c,v 1.16 2017/10/07 19:39:19 christos Exp $"); 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 44 #include <openssl/evp.h> 45 46 #include <errno.h> 47 #include <fcntl.h> 48 #include <pwd.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 #include <limits.h> 54 55 #include "xmalloc.h" 56 #include "ssh.h" 57 #include "log.h" 58 #include "sshkey.h" 59 #include "sshbuf.h" 60 #include "authfd.h" 61 #include "authfile.h" 62 #include "pathnames.h" 63 #include "misc.h" 64 #include "ssherr.h" 65 #include "digest.h" 66 67 /* argv0 */ 68 extern char *__progname; 69 70 /* Default files to add */ 71 static const char *default_files[] = { 72 _PATH_SSH_CLIENT_ID_RSA, 73 _PATH_SSH_CLIENT_ID_DSA, 74 _PATH_SSH_CLIENT_ID_ECDSA, 75 _PATH_SSH_CLIENT_ID_ED25519, 76 NULL 77 }; 78 79 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 80 81 /* Default lifetime (0 == forever) */ 82 static int lifetime = 0; 83 84 /* User has to confirm key use */ 85 static int confirm = 0; 86 87 /* we keep a cache of one passphrase */ 88 static char *pass = NULL; 89 static void 90 clear_pass(void) 91 { 92 if (pass) { 93 explicit_bzero(pass, strlen(pass)); 94 free(pass); 95 pass = NULL; 96 } 97 } 98 99 static int 100 delete_file(int agent_fd, const char *filename, int key_only, int qflag) 101 { 102 struct sshkey *public, *cert = NULL; 103 char *certpath = NULL, *comment = NULL; 104 int r, ret = -1; 105 106 if ((r = sshkey_load_public(filename, &public, &comment)) != 0) { 107 printf("Bad key file %s: %s\n", filename, ssh_err(r)); 108 return -1; 109 } 110 if ((r = ssh_remove_identity(agent_fd, public)) == 0) { 111 if (!qflag) { 112 fprintf(stderr, "Identity removed: %s (%s)\n", 113 filename, comment); 114 } 115 ret = 0; 116 } else 117 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 118 filename, ssh_err(r)); 119 120 if (key_only) 121 goto out; 122 123 /* Now try to delete the corresponding certificate too */ 124 free(comment); 125 comment = NULL; 126 xasprintf(&certpath, "%s-cert.pub", filename); 127 if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) { 128 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 129 error("Failed to load certificate \"%s\": %s", 130 certpath, ssh_err(r)); 131 goto out; 132 } 133 134 if (!sshkey_equal_public(cert, public)) 135 fatal("Certificate %s does not match private key %s", 136 certpath, filename); 137 138 if ((r = ssh_remove_identity(agent_fd, cert)) == 0) { 139 if (!qflag) { 140 fprintf(stderr, "Identity removed: %s (%s)\n", 141 certpath, comment); 142 } 143 ret = 0; 144 } else 145 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 146 certpath, ssh_err(r)); 147 148 out: 149 sshkey_free(cert); 150 sshkey_free(public); 151 free(certpath); 152 free(comment); 153 154 return ret; 155 } 156 157 /* Send a request to remove all identities. */ 158 static int 159 delete_all(int agent_fd) 160 { 161 int ret = -1; 162 163 /* 164 * Since the agent might be forwarded, old or non-OpenSSH, when asked 165 * to remove all keys, attempt to remove both protocol v.1 and v.2 166 * keys. 167 */ 168 if (ssh_remove_all_identities(agent_fd, 2) == 0) 169 ret = 0; 170 /* ignore error-code for ssh1 */ 171 ssh_remove_all_identities(agent_fd, 1); 172 173 if (ret == 0) 174 fprintf(stderr, "All identities removed.\n"); 175 else 176 fprintf(stderr, "Failed to remove all identities.\n"); 177 178 return ret; 179 } 180 181 static int 182 add_file(int agent_fd, const char *filename, int key_only, int qflag) 183 { 184 struct sshkey *private, *cert; 185 char *comment = NULL; 186 char msg[1024], *certpath = NULL; 187 int r, fd, ret = -1; 188 struct sshbuf *keyblob; 189 190 if (strcmp(filename, "-") == 0) { 191 fd = STDIN_FILENO; 192 filename = "(stdin)"; 193 } else if ((fd = open(filename, O_RDONLY)) < 0) { 194 perror(filename); 195 return -1; 196 } 197 198 /* 199 * Since we'll try to load a keyfile multiple times, permission errors 200 * will occur multiple times, so check perms first and bail if wrong. 201 */ 202 if (fd != STDIN_FILENO) { 203 if (sshkey_perm_ok(fd, filename) != 0) { 204 close(fd); 205 return -1; 206 } 207 } 208 if ((keyblob = sshbuf_new()) == NULL) 209 fatal("%s: sshbuf_new failed", __func__); 210 if ((r = sshkey_load_file(fd, keyblob)) != 0) { 211 fprintf(stderr, "Error loading key \"%s\": %s\n", 212 filename, ssh_err(r)); 213 sshbuf_free(keyblob); 214 close(fd); 215 return -1; 216 } 217 close(fd); 218 219 /* At first, try empty passphrase */ 220 if ((r = sshkey_parse_private_fileblob(keyblob, "", &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 /* try last */ 227 if (private == NULL && pass != NULL) { 228 if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private, 229 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 230 fprintf(stderr, "Error loading key \"%s\": %s\n", 231 filename, ssh_err(r)); 232 goto fail_load; 233 } 234 } 235 if (private == NULL) { 236 /* clear passphrase since it did not work */ 237 clear_pass(); 238 snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ", 239 filename, confirm ? " (will confirm each use)" : ""); 240 for (;;) { 241 pass = read_passphrase(msg, RP_ALLOW_STDIN); 242 if (strcmp(pass, "") == 0) 243 goto fail_load; 244 if ((r = sshkey_parse_private_fileblob(keyblob, pass, 245 &private, &comment)) == 0) 246 break; 247 else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 248 fprintf(stderr, 249 "Error loading key \"%s\": %s\n", 250 filename, ssh_err(r)); 251 fail_load: 252 clear_pass(); 253 sshbuf_free(keyblob); 254 return -1; 255 } 256 clear_pass(); 257 snprintf(msg, sizeof msg, 258 "Bad passphrase, try again for %s%s: ", filename, 259 confirm ? " (will confirm each use)" : ""); 260 } 261 } 262 if (comment == NULL || *comment == '\0') 263 comment = xstrdup(filename); 264 sshbuf_free(keyblob); 265 266 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 267 lifetime, confirm)) == 0) { 268 fprintf(stderr, "Identity added: %s (%s)\n", filename, comment); 269 ret = 0; 270 if (lifetime != 0) 271 fprintf(stderr, 272 "Lifetime set to %d seconds\n", lifetime); 273 if (confirm != 0) 274 fprintf(stderr, 275 "The user must confirm each use of the key\n"); 276 } else { 277 fprintf(stderr, "Could not add identity \"%s\": %s\n", 278 filename, ssh_err(r)); 279 } 280 281 /* Skip trying to load the cert if requested */ 282 if (key_only) 283 goto out; 284 285 /* Now try to add the certificate flavour too */ 286 xasprintf(&certpath, "%s-cert.pub", filename); 287 if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) { 288 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 289 error("Failed to load certificate \"%s\": %s", 290 certpath, ssh_err(r)); 291 goto out; 292 } 293 294 if (!sshkey_equal_public(cert, private)) { 295 error("Certificate %s does not match private key %s", 296 certpath, filename); 297 sshkey_free(cert); 298 goto out; 299 } 300 301 /* Graft with private bits */ 302 if ((r = sshkey_to_certified(private)) != 0) { 303 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r)); 304 sshkey_free(cert); 305 goto out; 306 } 307 if ((r = sshkey_cert_copy(cert, private)) != 0) { 308 error("%s: sshkey_cert_copy: %s", __func__, ssh_err(r)); 309 sshkey_free(cert); 310 goto out; 311 } 312 sshkey_free(cert); 313 314 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 315 lifetime, confirm)) != 0) { 316 error("Certificate %s (%s) add failed: %s", certpath, 317 private->cert->key_id, ssh_err(r)); 318 goto out; 319 } 320 fprintf(stderr, "Certificate added: %s (%s)\n", certpath, 321 private->cert->key_id); 322 if (lifetime != 0) 323 fprintf(stderr, "Lifetime set to %d seconds\n", lifetime); 324 if (confirm != 0) 325 fprintf(stderr, "The user must confirm each use of the key\n"); 326 out: 327 free(certpath); 328 free(comment); 329 sshkey_free(private); 330 331 return ret; 332 } 333 334 static int 335 update_card(int agent_fd, int add, const char *id) 336 { 337 char *pin = NULL; 338 int r, ret = -1; 339 340 if (add) { 341 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ", 342 RP_ALLOW_STDIN)) == NULL) 343 return -1; 344 } 345 346 if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin, 347 lifetime, confirm)) == 0) { 348 fprintf(stderr, "Card %s: %s\n", 349 add ? "added" : "removed", id); 350 ret = 0; 351 } else { 352 fprintf(stderr, "Could not %s card \"%s\": %s\n", 353 add ? "add" : "remove", id, ssh_err(r)); 354 ret = -1; 355 } 356 free(pin); 357 return ret; 358 } 359 360 static int 361 list_identities(int agent_fd, int do_fp) 362 { 363 char *fp; 364 int r; 365 struct ssh_identitylist *idlist; 366 size_t i; 367 368 if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 369 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 370 fprintf(stderr, "error fetching identities: %s\n", 371 ssh_err(r)); 372 else 373 printf("The agent has no identities.\n"); 374 return -1; 375 } 376 for (i = 0; i < idlist->nkeys; i++) { 377 if (do_fp) { 378 fp = sshkey_fingerprint(idlist->keys[i], 379 fingerprint_hash, SSH_FP_DEFAULT); 380 printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]), 381 fp == NULL ? "(null)" : fp, idlist->comments[i], 382 sshkey_type(idlist->keys[i])); 383 free(fp); 384 } else { 385 if ((r = sshkey_write(idlist->keys[i], 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 return 0; 395 } 396 397 static int 398 lock_agent(int agent_fd, int lock) 399 { 400 char prompt[100], *p1, *p2; 401 int r, passok = 1, ret = -1; 402 403 strlcpy(prompt, "Enter lock password: ", sizeof(prompt)); 404 p1 = read_passphrase(prompt, RP_ALLOW_STDIN); 405 if (lock) { 406 strlcpy(prompt, "Again: ", sizeof prompt); 407 p2 = read_passphrase(prompt, RP_ALLOW_STDIN); 408 if (strcmp(p1, p2) != 0) { 409 fprintf(stderr, "Passwords do not match.\n"); 410 passok = 0; 411 } 412 explicit_bzero(p2, strlen(p2)); 413 free(p2); 414 } 415 if (passok) { 416 if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) { 417 fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un"); 418 ret = 0; 419 } else { 420 fprintf(stderr, "Failed to %slock agent: %s\n", 421 lock ? "" : "un", ssh_err(r)); 422 } 423 } 424 explicit_bzero(p1, strlen(p1)); 425 free(p1); 426 return (ret); 427 } 428 429 static int 430 do_file(int agent_fd, int deleting, int key_only, char *file, int qflag) 431 { 432 if (deleting) { 433 if (delete_file(agent_fd, file, key_only, qflag) == -1) 434 return -1; 435 } else { 436 if (add_file(agent_fd, file, key_only, qflag) == -1) 437 return -1; 438 } 439 return 0; 440 } 441 442 static void 443 usage(void) 444 { 445 fprintf(stderr, "usage: %s [options] [file ...]\n", __progname); 446 fprintf(stderr, "Options:\n"); 447 fprintf(stderr, " -l List fingerprints of all identities.\n"); 448 fprintf(stderr, " -E hash Specify hash algorithm used for fingerprints.\n"); 449 fprintf(stderr, " -L List public key parameters of all identities.\n"); 450 fprintf(stderr, " -k Load only keys and not certificates.\n"); 451 fprintf(stderr, " -c Require confirmation to sign using identities\n"); 452 fprintf(stderr, " -t life Set lifetime (in seconds) when adding identities.\n"); 453 fprintf(stderr, " -d Delete identity.\n"); 454 fprintf(stderr, " -D Delete all identities.\n"); 455 fprintf(stderr, " -x Lock agent.\n"); 456 fprintf(stderr, " -X Unlock agent.\n"); 457 fprintf(stderr, " -s pkcs11 Add keys from PKCS#11 provider.\n"); 458 fprintf(stderr, " -e pkcs11 Remove keys provided by PKCS#11 provider.\n"); 459 fprintf(stderr, " -q Be quiet after a successful operation.\n"); 460 } 461 462 int 463 main(int argc, char **argv) 464 { 465 extern char *optarg; 466 extern int optind; 467 int agent_fd; 468 char *pkcs11provider = NULL; 469 int r, i, ch, deleting = 0, ret = 0, key_only = 0; 470 int xflag = 0, lflag = 0, Dflag = 0, qflag = 0; 471 472 ssh_malloc_init(); /* must be called before any mallocs */ 473 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 474 sanitise_stdfd(); 475 476 OpenSSL_add_all_algorithms(); 477 478 setvbuf(stdout, NULL, _IOLBF, 0); 479 480 /* First, get a connection to the authentication agent. */ 481 switch (r = ssh_get_authentication_socket(&agent_fd)) { 482 case 0: 483 break; 484 case SSH_ERR_AGENT_NOT_PRESENT: 485 fprintf(stderr, "Could not open a connection to your " 486 "authentication agent.\n"); 487 exit(2); 488 default: 489 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r)); 490 exit(2); 491 } 492 493 while ((ch = getopt(argc, argv, "klLcdDxXE:e:qs:t:")) != -1) { 494 switch (ch) { 495 case 'E': 496 fingerprint_hash = ssh_digest_alg_by_name(optarg); 497 if (fingerprint_hash == -1) 498 fatal("Invalid hash algorithm \"%s\"", optarg); 499 break; 500 case 'k': 501 key_only = 1; 502 break; 503 case 'l': 504 case 'L': 505 if (lflag != 0) 506 fatal("-%c flag already specified", lflag); 507 lflag = ch; 508 break; 509 case 'x': 510 case 'X': 511 if (xflag != 0) 512 fatal("-%c flag already specified", xflag); 513 xflag = ch; 514 break; 515 case 'c': 516 confirm = 1; 517 break; 518 case 'd': 519 deleting = 1; 520 break; 521 case 'D': 522 Dflag = 1; 523 break; 524 case 's': 525 pkcs11provider = optarg; 526 break; 527 case 'e': 528 deleting = 1; 529 pkcs11provider = optarg; 530 break; 531 case 't': 532 if ((lifetime = convtime(optarg)) == -1) { 533 fprintf(stderr, "Invalid lifetime\n"); 534 ret = 1; 535 goto done; 536 } 537 break; 538 case 'q': 539 qflag = 1; 540 break; 541 default: 542 usage(); 543 ret = 1; 544 goto done; 545 } 546 } 547 548 if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1) 549 fatal("Invalid combination of actions"); 550 else if (xflag) { 551 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1) 552 ret = 1; 553 goto done; 554 } else if (lflag) { 555 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1) 556 ret = 1; 557 goto done; 558 } else if (Dflag) { 559 if (delete_all(agent_fd) == -1) 560 ret = 1; 561 goto done; 562 } 563 564 argc -= optind; 565 argv += optind; 566 if (pkcs11provider != NULL) { 567 if (update_card(agent_fd, !deleting, pkcs11provider) == -1) 568 ret = 1; 569 goto done; 570 } 571 if (argc == 0) { 572 char buf[PATH_MAX]; 573 struct passwd *pw; 574 struct stat st; 575 int count = 0; 576 577 if ((pw = getpwuid(getuid())) == NULL) { 578 fprintf(stderr, "No user found with uid %u\n", 579 (u_int)getuid()); 580 ret = 1; 581 goto done; 582 } 583 584 for (i = 0; default_files[i]; i++) { 585 snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, 586 default_files[i]); 587 if (stat(buf, &st) < 0) 588 continue; 589 if (do_file(agent_fd, deleting, key_only, buf, 590 qflag) == -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], qflag) == -1) 601 ret = 1; 602 } 603 } 604 clear_pass(); 605 606 done: 607 ssh_close_authentication_socket(agent_fd); 608 return ret; 609 } 610