1 /* $NetBSD: ssh-add.c,v 1.14 2016/12/25 00:07:47 christos Exp $ */ 2 /* $OpenBSD: ssh-add.c,v 1.128 2016/02/15 09:47:49 dtucker Exp $ */ 3 4 /* 5 * Author: Tatu Ylonen <ylo@cs.hut.fi> 6 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 7 * All rights reserved 8 * Adds an identity to the authentication server, or removes an identity. 9 * 10 * As far as I am concerned, the code I have written for this software 11 * can be used freely for any purpose. Any derived versions of this 12 * software must be clearly marked as such, and if the derived work is 13 * incompatible with the protocol description in the RFC file, it must be 14 * called by a name other than "ssh" or "Secure Shell". 15 * 16 * SSH2 implementation, 17 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 #include "includes.h" 41 __RCSID("$NetBSD: ssh-add.c,v 1.14 2016/12/25 00:07:47 christos Exp $"); 42 #include <sys/types.h> 43 #include <sys/stat.h> 44 45 #include <openssl/evp.h> 46 47 #include <errno.h> 48 #include <fcntl.h> 49 #include <pwd.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <unistd.h> 54 #include <limits.h> 55 56 #include "xmalloc.h" 57 #include "ssh.h" 58 #include "rsa.h" 59 #include "log.h" 60 #include "sshkey.h" 61 #include "sshbuf.h" 62 #include "authfd.h" 63 #include "authfile.h" 64 #include "pathnames.h" 65 #include "misc.h" 66 #include "ssherr.h" 67 #include "digest.h" 68 69 /* argv0 */ 70 extern char *__progname; 71 72 /* Default files to add */ 73 static const char *default_files[] = { 74 _PATH_SSH_CLIENT_ID_RSA, 75 _PATH_SSH_CLIENT_ID_DSA, 76 _PATH_SSH_CLIENT_ID_ECDSA, 77 _PATH_SSH_CLIENT_ID_ED25519, 78 #ifdef WITH_SSH1 79 _PATH_SSH_CLIENT_IDENTITY, 80 #endif 81 NULL 82 }; 83 84 static int fingerprint_hash = SSH_FP_HASH_DEFAULT; 85 86 /* Default lifetime (0 == forever) */ 87 static int lifetime = 0; 88 89 /* User has to confirm key use */ 90 static int confirm = 0; 91 92 /* we keep a cache of one passphrase */ 93 static char *pass = NULL; 94 static void 95 clear_pass(void) 96 { 97 if (pass) { 98 explicit_bzero(pass, strlen(pass)); 99 free(pass); 100 pass = NULL; 101 } 102 } 103 104 static int 105 delete_file(int agent_fd, const char *filename, int key_only) 106 { 107 struct sshkey *public, *cert = NULL; 108 char *certpath = NULL, *comment = NULL; 109 int r, ret = -1; 110 111 if ((r = sshkey_load_public(filename, &public, &comment)) != 0) { 112 printf("Bad key file %s: %s\n", filename, ssh_err(r)); 113 return -1; 114 } 115 if ((r = ssh_remove_identity(agent_fd, public)) == 0) { 116 fprintf(stderr, "Identity removed: %s (%s)\n", filename, comment); 117 ret = 0; 118 } else 119 fprintf(stderr, "Could not remove identity \"%s\": %s\n", 120 filename, ssh_err(r)); 121 122 if (key_only) 123 goto out; 124 125 /* Now try to delete the corresponding certificate too */ 126 free(comment); 127 comment = NULL; 128 xasprintf(&certpath, "%s-cert.pub", filename); 129 if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) { 130 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 131 error("Failed to load certificate \"%s\": %s", 132 certpath, ssh_err(r)); 133 goto out; 134 } 135 136 if (!sshkey_equal_public(cert, public)) 137 fatal("Certificate %s does not match private key %s", 138 certpath, filename); 139 140 if ((r = ssh_remove_identity(agent_fd, cert)) == 0) { 141 fprintf(stderr, "Identity removed: %s (%s)\n", certpath, 142 comment); 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 if (ssh_remove_all_identities(agent_fd, 2) == 0) 164 ret = 0; 165 /* ignore error-code for ssh1 */ 166 ssh_remove_all_identities(agent_fd, 1); 167 168 if (ret == 0) 169 fprintf(stderr, "All identities removed.\n"); 170 else 171 fprintf(stderr, "Failed to remove all identities.\n"); 172 173 return ret; 174 } 175 176 static int 177 add_file(int agent_fd, const char *filename, int key_only) 178 { 179 struct sshkey *private, *cert; 180 char *comment = NULL; 181 char msg[1024], *certpath = NULL; 182 int r, fd, ret = -1; 183 struct sshbuf *keyblob; 184 185 if (strcmp(filename, "-") == 0) { 186 fd = STDIN_FILENO; 187 filename = "(stdin)"; 188 } else if ((fd = open(filename, O_RDONLY)) < 0) { 189 perror(filename); 190 return -1; 191 } 192 193 /* 194 * Since we'll try to load a keyfile multiple times, permission errors 195 * will occur multiple times, so check perms first and bail if wrong. 196 */ 197 if (fd != STDIN_FILENO) { 198 if (sshkey_perm_ok(fd, filename) != 0) { 199 close(fd); 200 return -1; 201 } 202 } 203 if ((keyblob = sshbuf_new()) == NULL) 204 fatal("%s: sshbuf_new failed", __func__); 205 if ((r = sshkey_load_file(fd, keyblob)) != 0) { 206 fprintf(stderr, "Error loading key \"%s\": %s\n", 207 filename, ssh_err(r)); 208 sshbuf_free(keyblob); 209 close(fd); 210 return -1; 211 } 212 close(fd); 213 214 /* At first, try empty passphrase */ 215 if ((r = sshkey_parse_private_fileblob(keyblob, "", &private, 216 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 217 fprintf(stderr, "Error loading key \"%s\": %s\n", 218 filename, ssh_err(r)); 219 goto fail_load; 220 } 221 /* try last */ 222 if (private == NULL && pass != NULL) { 223 if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private, 224 &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 225 fprintf(stderr, "Error loading key \"%s\": %s\n", 226 filename, ssh_err(r)); 227 goto fail_load; 228 } 229 } 230 if (private == NULL) { 231 /* clear passphrase since it did not work */ 232 clear_pass(); 233 snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ", 234 filename, confirm ? " (will confirm each use)" : ""); 235 for (;;) { 236 pass = read_passphrase(msg, RP_ALLOW_STDIN); 237 if (strcmp(pass, "") == 0) 238 goto fail_load; 239 if ((r = sshkey_parse_private_fileblob(keyblob, pass, 240 &private, &comment)) == 0) 241 break; 242 else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) { 243 fprintf(stderr, 244 "Error loading key \"%s\": %s\n", 245 filename, ssh_err(r)); 246 fail_load: 247 clear_pass(); 248 sshbuf_free(keyblob); 249 return -1; 250 } 251 clear_pass(); 252 snprintf(msg, sizeof msg, 253 "Bad passphrase, try again for %s%s: ", filename, 254 confirm ? " (will confirm each use)" : ""); 255 } 256 } 257 if (comment == NULL || *comment == '\0') 258 comment = xstrdup(filename); 259 sshbuf_free(keyblob); 260 261 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 262 lifetime, confirm)) == 0) { 263 fprintf(stderr, "Identity added: %s (%s)\n", filename, comment); 264 ret = 0; 265 if (lifetime != 0) 266 fprintf(stderr, 267 "Lifetime set to %d seconds\n", lifetime); 268 if (confirm != 0) 269 fprintf(stderr, 270 "The user must confirm each use of the key\n"); 271 } else { 272 fprintf(stderr, "Could not add identity \"%s\": %s\n", 273 filename, ssh_err(r)); 274 } 275 276 /* Skip trying to load the cert if requested */ 277 if (key_only) 278 goto out; 279 280 /* Now try to add the certificate flavour too */ 281 xasprintf(&certpath, "%s-cert.pub", filename); 282 if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) { 283 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT) 284 error("Failed to load certificate \"%s\": %s", 285 certpath, ssh_err(r)); 286 goto out; 287 } 288 289 if (!sshkey_equal_public(cert, private)) { 290 error("Certificate %s does not match private key %s", 291 certpath, filename); 292 sshkey_free(cert); 293 goto out; 294 } 295 296 /* Graft with private bits */ 297 if ((r = sshkey_to_certified(private)) != 0) { 298 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r)); 299 sshkey_free(cert); 300 goto out; 301 } 302 if ((r = sshkey_cert_copy(cert, private)) != 0) { 303 error("%s: key_cert_copy: %s", __func__, ssh_err(r)); 304 sshkey_free(cert); 305 goto out; 306 } 307 sshkey_free(cert); 308 309 if ((r = ssh_add_identity_constrained(agent_fd, private, comment, 310 lifetime, confirm)) != 0) { 311 error("Certificate %s (%s) add failed: %s", certpath, 312 private->cert->key_id, ssh_err(r)); 313 goto out; 314 } 315 fprintf(stderr, "Certificate added: %s (%s)\n", certpath, 316 private->cert->key_id); 317 if (lifetime != 0) 318 fprintf(stderr, "Lifetime set to %d seconds\n", lifetime); 319 if (confirm != 0) 320 fprintf(stderr, "The user must confirm each use of the key\n"); 321 out: 322 free(certpath); 323 free(comment); 324 sshkey_free(private); 325 326 return ret; 327 } 328 329 static int 330 update_card(int agent_fd, int add, const char *id) 331 { 332 char *pin = NULL; 333 int r, ret = -1; 334 335 if (add) { 336 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ", 337 RP_ALLOW_STDIN)) == NULL) 338 return -1; 339 } 340 341 if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin, 342 lifetime, confirm)) == 0) { 343 fprintf(stderr, "Card %s: %s\n", 344 add ? "added" : "removed", id); 345 ret = 0; 346 } else { 347 fprintf(stderr, "Could not %s card \"%s\": %s\n", 348 add ? "add" : "remove", id, ssh_err(r)); 349 ret = -1; 350 } 351 free(pin); 352 return ret; 353 } 354 355 static int 356 list_identities(int agent_fd, int do_fp) 357 { 358 char *fp; 359 int r, had_identities = 0; 360 struct ssh_identitylist *idlist; 361 size_t i; 362 #ifdef WITH_SSH1 363 int version = 1; 364 #else 365 int version = 2; 366 #endif 367 368 for (; version <= 2; version++) { 369 if ((r = ssh_fetch_identitylist(agent_fd, version, 370 &idlist)) != 0) { 371 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 372 fprintf(stderr, "error fetching identities for " 373 "protocol %d: %s\n", version, ssh_err(r)); 374 continue; 375 } 376 for (i = 0; i < idlist->nkeys; i++) { 377 had_identities = 1; 378 if (do_fp) { 379 fp = sshkey_fingerprint(idlist->keys[i], 380 fingerprint_hash, SSH_FP_DEFAULT); 381 printf("%u %s %s (%s)\n", 382 sshkey_size(idlist->keys[i]), 383 fp == NULL ? "(null)" : fp, 384 idlist->comments[i], 385 sshkey_type(idlist->keys[i])); 386 free(fp); 387 } else { 388 if ((r = sshkey_write(idlist->keys[i], 389 stdout)) != 0) { 390 fprintf(stderr, "sshkey_write: %s\n", 391 ssh_err(r)); 392 continue; 393 } 394 fprintf(stdout, " %s\n", idlist->comments[i]); 395 } 396 } 397 ssh_free_identitylist(idlist); 398 } 399 if (!had_identities) { 400 printf("The agent has no identities.\n"); 401 return -1; 402 } 403 return 0; 404 } 405 406 static int 407 lock_agent(int agent_fd, int lock) 408 { 409 char prompt[100], *p1, *p2; 410 int r, passok = 1, ret = -1; 411 412 strlcpy(prompt, "Enter lock password: ", sizeof(prompt)); 413 p1 = read_passphrase(prompt, RP_ALLOW_STDIN); 414 if (lock) { 415 strlcpy(prompt, "Again: ", sizeof prompt); 416 p2 = read_passphrase(prompt, RP_ALLOW_STDIN); 417 if (strcmp(p1, p2) != 0) { 418 fprintf(stderr, "Passwords do not match.\n"); 419 passok = 0; 420 } 421 explicit_bzero(p2, strlen(p2)); 422 free(p2); 423 } 424 if (passok) { 425 if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) { 426 fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un"); 427 ret = 0; 428 } else { 429 fprintf(stderr, "Failed to %slock agent: %s\n", 430 lock ? "" : "un", ssh_err(r)); 431 } 432 } 433 explicit_bzero(p1, strlen(p1)); 434 free(p1); 435 return (ret); 436 } 437 438 static int 439 do_file(int agent_fd, int deleting, int key_only, char *file) 440 { 441 if (deleting) { 442 if (delete_file(agent_fd, file, key_only) == -1) 443 return -1; 444 } else { 445 if (add_file(agent_fd, file, key_only) == -1) 446 return -1; 447 } 448 return 0; 449 } 450 451 static void 452 usage(void) 453 { 454 fprintf(stderr, "usage: %s [options] [file ...]\n", __progname); 455 fprintf(stderr, "Options:\n"); 456 fprintf(stderr, " -l List fingerprints of all identities.\n"); 457 fprintf(stderr, " -E hash Specify hash algorithm used for fingerprints.\n"); 458 fprintf(stderr, " -L List public key parameters of all identities.\n"); 459 fprintf(stderr, " -k Load only keys and not certificates.\n"); 460 fprintf(stderr, " -c Require confirmation to sign using identities\n"); 461 fprintf(stderr, " -t life Set lifetime (in seconds) when adding identities.\n"); 462 fprintf(stderr, " -d Delete identity.\n"); 463 fprintf(stderr, " -D Delete all identities.\n"); 464 fprintf(stderr, " -x Lock agent.\n"); 465 fprintf(stderr, " -X Unlock agent.\n"); 466 fprintf(stderr, " -s pkcs11 Add keys from PKCS#11 provider.\n"); 467 fprintf(stderr, " -e pkcs11 Remove keys provided by PKCS#11 provider.\n"); 468 } 469 470 int 471 main(int argc, char **argv) 472 { 473 extern char *optarg; 474 extern int optind; 475 int agent_fd; 476 char *pkcs11provider = NULL; 477 int r, i, ch, deleting = 0, ret = 0, key_only = 0; 478 int xflag = 0, lflag = 0, Dflag = 0; 479 480 ssh_malloc_init(); /* must be called before any mallocs */ 481 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ 482 sanitise_stdfd(); 483 484 OpenSSL_add_all_algorithms(); 485 486 setvbuf(stdout, NULL, _IOLBF, 0); 487 488 /* First, get a connection to the authentication agent. */ 489 switch (r = ssh_get_authentication_socket(&agent_fd)) { 490 case 0: 491 break; 492 case SSH_ERR_AGENT_NOT_PRESENT: 493 fprintf(stderr, "Could not open a connection to your " 494 "authentication agent.\n"); 495 exit(2); 496 default: 497 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r)); 498 exit(2); 499 } 500 501 while ((ch = getopt(argc, argv, "klLcdDxXE:e:s:t:")) != -1) { 502 switch (ch) { 503 case 'E': 504 fingerprint_hash = ssh_digest_alg_by_name(optarg); 505 if (fingerprint_hash == -1) 506 fatal("Invalid hash algorithm \"%s\"", optarg); 507 break; 508 case 'k': 509 key_only = 1; 510 break; 511 case 'l': 512 case 'L': 513 if (lflag != 0) 514 fatal("-%c flag already specified", lflag); 515 lflag = ch; 516 break; 517 case 'x': 518 case 'X': 519 if (xflag != 0) 520 fatal("-%c flag already specified", xflag); 521 xflag = ch; 522 break; 523 case 'c': 524 confirm = 1; 525 break; 526 case 'd': 527 deleting = 1; 528 break; 529 case 'D': 530 Dflag = 1; 531 break; 532 case 's': 533 pkcs11provider = optarg; 534 break; 535 case 'e': 536 deleting = 1; 537 pkcs11provider = optarg; 538 break; 539 case 't': 540 if ((lifetime = convtime(optarg)) == -1) { 541 fprintf(stderr, "Invalid lifetime\n"); 542 ret = 1; 543 goto done; 544 } 545 break; 546 default: 547 usage(); 548 ret = 1; 549 goto done; 550 } 551 } 552 553 if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1) 554 fatal("Invalid combination of actions"); 555 else if (xflag) { 556 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1) 557 ret = 1; 558 goto done; 559 } else if (lflag) { 560 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1) 561 ret = 1; 562 goto done; 563 } else if (Dflag) { 564 if (delete_all(agent_fd) == -1) 565 ret = 1; 566 goto done; 567 } 568 569 argc -= optind; 570 argv += optind; 571 if (pkcs11provider != NULL) { 572 if (update_card(agent_fd, !deleting, pkcs11provider) == -1) 573 ret = 1; 574 goto done; 575 } 576 if (argc == 0) { 577 char buf[PATH_MAX]; 578 struct passwd *pw; 579 struct stat st; 580 int count = 0; 581 582 if ((pw = getpwuid(getuid())) == NULL) { 583 fprintf(stderr, "No user found with uid %u\n", 584 (u_int)getuid()); 585 ret = 1; 586 goto done; 587 } 588 589 for (i = 0; default_files[i]; i++) { 590 snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir, 591 default_files[i]); 592 if (stat(buf, &st) < 0) 593 continue; 594 if (do_file(agent_fd, deleting, key_only, buf) == -1) 595 ret = 1; 596 else 597 count++; 598 } 599 if (count == 0) 600 ret = 1; 601 } else { 602 for (i = 0; i < argc; i++) { 603 if (do_file(agent_fd, deleting, key_only, 604 argv[i]) == -1) 605 ret = 1; 606 } 607 } 608 clear_pass(); 609 610 done: 611 ssh_close_authentication_socket(agent_fd); 612 return ret; 613 } 614