crypto/openssh/ssh-add.c

   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 "includes.h"
  39
  40 #include <sys/types.h>
  41 #include <sys/stat.h>
  42
  43 #include <openssl/evp.h>
  44 #include "openbsd-compat/openssl-compat.h"
  45
  46 #include <errno.h>
  47 #include <fcntl.h>
  48 #include <pwd.h>
  49 #include <stdarg.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 char *default_files[] = {
  74 #ifdef WITH_OPENSSL
  75         _PATH_SSH_CLIENT_ID_RSA,
  76         _PATH_SSH_CLIENT_ID_DSA,
  77 #ifdef OPENSSL_HAS_ECC
  78         _PATH_SSH_CLIENT_ID_ECDSA,
  79 #endif
  80 #endif /* WITH_OPENSSL */
  81         _PATH_SSH_CLIENT_ID_ED25519,
  82 #ifdef WITH_SSH1
  83         _PATH_SSH_CLIENT_IDENTITY,
  84 #endif
  85         NULL
  86 };
  87
  88 static int fingerprint_hash = SSH_FP_HASH_DEFAULT;
  89
  90 /* Default lifetime (0 == forever) */
  91 static int lifetime = 0;
  92
  93 /* User has to confirm key use */
  94 static int confirm = 0;
  95
  96 /* we keep a cache of one passphrase */
  97 static char *pass = NULL;
  98 static void
  99 clear_pass(void)
 100 {
 101         if (pass) {
 102                 explicit_bzero(pass, strlen(pass));
 103                 free(pass);
 104                 pass = NULL;
 105         }
 106 }
 107
 108 static int
 109 delete_file(int agent_fd, const char *filename, int key_only)
 110 {
 111         struct sshkey *public, *cert = NULL;
 112         char *certpath = NULL, *comment = NULL;
 113         int r, ret = -1;
 114
 115         if ((r = sshkey_load_public(filename, &public,  &comment)) != 0) {
 116                 printf("Bad key file %s: %s\n", filename, ssh_err(r));
 117                 return -1;
 118         }
 119         if ((r = ssh_remove_identity(agent_fd, public)) == 0) {
 120                 fprintf(stderr, "Identity removed: %s (%s)\n", filename, comment);
 121                 ret = 0;
 122         } else
 123                 fprintf(stderr, "Could not remove identity \"%s\": %s\n",
 124                     filename, ssh_err(r));
 125
 126         if (key_only)
 127                 goto out;
 128
 129         /* Now try to delete the corresponding certificate too */
 130         free(comment);
 131         comment = NULL;
 132         xasprintf(&certpath, "%s-cert.pub", filename);
 133         if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) {
 134                 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
 135                         error("Failed to load certificate \"%s\": %s",
 136                             certpath, ssh_err(r));
 137                 goto out;
 138         }
 139
 140         if (!sshkey_equal_public(cert, public))
 141                 fatal("Certificate %s does not match private key %s",
 142                     certpath, filename);
 143
 144         if ((r = ssh_remove_identity(agent_fd, cert)) == 0) {
 145                 fprintf(stderr, "Identity removed: %s (%s)\n", certpath,
 146                     comment);
 147                 ret = 0;
 148         } else
 149                 fprintf(stderr, "Could not remove identity \"%s\": %s\n",
 150                     certpath, ssh_err(r));
 151
 152  out:
 153         sshkey_free(cert);
 154         sshkey_free(public);
 155         free(certpath);
 156         free(comment);
 157
 158         return ret;
 159 }
 160
 161 /* Send a request to remove all identities. */
 162 static int
 163 delete_all(int agent_fd)
 164 {
 165         int ret = -1;
 166
 167         if (ssh_remove_all_identities(agent_fd, 2) == 0)
 168                 ret = 0;
 169         /* ignore error-code for ssh1 */
 170         ssh_remove_all_identities(agent_fd, 1);
 171
 172         if (ret == 0)
 173                 fprintf(stderr, "All identities removed.\n");
 174         else
 175                 fprintf(stderr, "Failed to remove all identities.\n");
 176
 177         return ret;
 178 }
 179
 180 static int
 181 add_file(int agent_fd, const char *filename, int key_only)
 182 {
 183         struct sshkey *private, *cert;
 184         char *comment = NULL;
 185         char msg[1024], *certpath = NULL;
 186         int r, fd, ret = -1;
 187         struct sshbuf *keyblob;
 188
 189         if (strcmp(filename, "-") == 0) {
 190                 fd = STDIN_FILENO;
 191                 filename = "(stdin)";
 192         } else if ((fd = open(filename, O_RDONLY)) < 0) {
 193                 perror(filename);
 194                 return -1;
 195         }
 196
 197         /*
 198          * Since we'll try to load a keyfile multiple times, permission errors
 199          * will occur multiple times, so check perms first and bail if wrong.
 200          */
 201         if (fd != STDIN_FILENO) {
 202                 if (sshkey_perm_ok(fd, filename) != 0) {
 203                         close(fd);
 204                         return -1;
 205                 }
 206         }
 207         if ((keyblob = sshbuf_new()) == NULL)
 208                 fatal("%s: sshbuf_new failed", __func__);
 209         if ((r = sshkey_load_file(fd, keyblob)) != 0) {
 210                 fprintf(stderr, "Error loading key \"%s\": %s\n",
 211                     filename, ssh_err(r));
 212                 sshbuf_free(keyblob);
 213                 close(fd);
 214                 return -1;
 215         }
 216         close(fd);
 217
 218         /* At first, try empty passphrase */
 219         if ((r = sshkey_parse_private_fileblob(keyblob, "", &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         /* try last */
 226         if (private == NULL && pass != NULL) {
 227                 if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private,
 228                     &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
 229                         fprintf(stderr, "Error loading key \"%s\": %s\n",
 230                             filename, ssh_err(r));
 231                         goto fail_load;
 232                 }
 233         }
 234         if (private == NULL) {
 235                 /* clear passphrase since it did not work */
 236                 clear_pass();
 237                 snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ",
 238                     filename, confirm ? " (will confirm each use)" : "");
 239                 for (;;) {
 240                         pass = read_passphrase(msg, RP_ALLOW_STDIN);
 241                         if (strcmp(pass, "") == 0)
 242                                 goto fail_load;
 243                         if ((r = sshkey_parse_private_fileblob(keyblob, pass,
 244                             &private, &comment)) == 0)
 245                                 break;
 246                         else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
 247                                 fprintf(stderr,
 248                                     "Error loading key \"%s\": %s\n",
 249                                     filename, ssh_err(r));
 250  fail_load:
 251                                 clear_pass();
 252                                 sshbuf_free(keyblob);
 253                                 return -1;
 254                         }
 255                         clear_pass();
 256                         snprintf(msg, sizeof msg,
 257                             "Bad passphrase, try again for %s%s: ", filename,
 258                             confirm ? " (will confirm each use)" : "");
 259                 }
 260         }
 261         if (comment == NULL || *comment == '\0')
 262                 comment = xstrdup(filename);
 263         sshbuf_free(keyblob);
 264
 265         if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
 266             lifetime, confirm)) == 0) {
 267                 fprintf(stderr, "Identity added: %s (%s)\n", filename, comment);
 268                 ret = 0;
 269                 if (lifetime != 0)
 270                         fprintf(stderr,
 271                             "Lifetime set to %d seconds\n", lifetime);
 272                 if (confirm != 0)
 273                         fprintf(stderr,
 274                             "The user must confirm each use of the key\n");
 275         } else {
 276                 fprintf(stderr, "Could not add identity \"%s\": %s\n",
 277                     filename, ssh_err(r));
 278         }
 279
 280         /* Skip trying to load the cert if requested */
 281         if (key_only)
 282                 goto out;
 283
 284         /* Now try to add the certificate flavour too */
 285         xasprintf(&certpath, "%s-cert.pub", filename);
 286         if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) {
 287                 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
 288                         error("Failed to load certificate \"%s\": %s",
 289                             certpath, ssh_err(r));
 290                 goto out;
 291         }
 292
 293         if (!sshkey_equal_public(cert, private)) {
 294                 error("Certificate %s does not match private key %s",
 295                     certpath, filename);
 296                 sshkey_free(cert);
 297                 goto out;
 298         }
 299
 300         /* Graft with private bits */
 301         if ((r = sshkey_to_certified(private)) != 0) {
 302                 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r));
 303                 sshkey_free(cert);
 304                 goto out;
 305         }
 306         if ((r = sshkey_cert_copy(cert, private)) != 0) {
 307                 error("%s: key_cert_copy: %s", __func__, ssh_err(r));
 308                 sshkey_free(cert);
 309                 goto out;
 310         }
 311         sshkey_free(cert);
 312
 313         if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
 314             lifetime, confirm)) != 0) {
 315                 error("Certificate %s (%s) add failed: %s", certpath,
 316                     private->cert->key_id, ssh_err(r));
 317                 goto out;
 318         }
 319         fprintf(stderr, "Certificate added: %s (%s)\n", certpath,
 320             private->cert->key_id);
 321         if (lifetime != 0)
 322                 fprintf(stderr, "Lifetime set to %d seconds\n", lifetime);
 323         if (confirm != 0)
 324                 fprintf(stderr, "The user must confirm each use of the key\n");
 325  out:
 326         free(certpath);
 327         free(comment);
 328         sshkey_free(private);
 329
 330         return ret;
 331 }
 332
 333 static int
 334 update_card(int agent_fd, int add, const char *id)
 335 {
 336         char *pin = NULL;
 337         int r, ret = -1;
 338
 339         if (add) {
 340                 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ",
 341                     RP_ALLOW_STDIN)) == NULL)
 342                         return -1;
 343         }
 344
 345         if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin,
 346             lifetime, confirm)) == 0) {
 347                 fprintf(stderr, "Card %s: %s\n",
 348                     add ? "added" : "removed", id);
 349                 ret = 0;
 350         } else {
 351                 fprintf(stderr, "Could not %s card \"%s\": %s\n",
 352                     add ? "add" : "remove", id, ssh_err(r));
 353                 ret = -1;
 354         }
 355         free(pin);
 356         return ret;
 357 }
 358
 359 static int
 360 list_identities(int agent_fd, int do_fp)
 361 {
 362         char *fp;
 363         int r, had_identities = 0;
 364         struct ssh_identitylist *idlist;
 365         size_t i;
 366 #ifdef WITH_SSH1
 367         int version = 1;
 368 #else
 369         int version = 2;
 370 #endif
 371
 372         for (; version <= 2; version++) {
 373                 if ((r = ssh_fetch_identitylist(agent_fd, version,
 374                     &idlist)) != 0) {
 375                         if (r != SSH_ERR_AGENT_NO_IDENTITIES)
 376                                 fprintf(stderr, "error fetching identities for "
 377                                     "protocol %d: %s\n", version, ssh_err(r));
 378                         continue;
 379                 }
 380                 for (i = 0; i < idlist->nkeys; i++) {
 381                         had_identities = 1;
 382                         if (do_fp) {
 383                                 fp = sshkey_fingerprint(idlist->keys[i],
 384                                     fingerprint_hash, SSH_FP_DEFAULT);
 385                                 printf("%u %s %s (%s)\n",
 386                                     sshkey_size(idlist->keys[i]),
 387                                     fp == NULL ? "(null)" : fp,
 388                                     idlist->comments[i],
 389                                     sshkey_type(idlist->keys[i]));
 390                                 free(fp);
 391                         } else {
 392                                 if ((r = sshkey_write(idlist->keys[i],
 393                                     stdout)) != 0) {
 394                                         fprintf(stderr, "sshkey_write: %s\n",
 395                                             ssh_err(r));
 396                                         continue;
 397                                 }
 398                                 fprintf(stdout, " %s\n", idlist->comments[i]);
 399                         }
 400                 }
 401                 ssh_free_identitylist(idlist);
 402         }
 403         if (!had_identities) {
 404                 printf("The agent has no identities.\n");
 405                 return -1;
 406         }
 407         return 0;
 408 }
 409
 410 static int
 411 lock_agent(int agent_fd, int lock)
 412 {
 413         char prompt[100], *p1, *p2;
 414         int r, passok = 1, ret = -1;
 415
 416         strlcpy(prompt, "Enter lock password: ", sizeof(prompt));
 417         p1 = read_passphrase(prompt, RP_ALLOW_STDIN);
 418         if (lock) {
 419                 strlcpy(prompt, "Again: ", sizeof prompt);
 420                 p2 = read_passphrase(prompt, RP_ALLOW_STDIN);
 421                 if (strcmp(p1, p2) != 0) {
 422                         fprintf(stderr, "Passwords do not match.\n");
 423                         passok = 0;
 424                 }
 425                 explicit_bzero(p2, strlen(p2));
 426                 free(p2);
 427         }
 428         if (passok) {
 429                 if ((r = ssh_lock_agent(agent_fd, lock, p1)) == 0) {
 430                         fprintf(stderr, "Agent %slocked.\n", lock ? "" : "un");
 431                         ret = 0;
 432                 } else {
 433                         fprintf(stderr, "Failed to %slock agent: %s\n",
 434                             lock ? "" : "un", ssh_err(r));
 435                 }
 436         }
 437         explicit_bzero(p1, strlen(p1));
 438         free(p1);
 439         return (ret);
 440 }
 441
 442 static int
 443 do_file(int agent_fd, int deleting, int key_only, char *file)
 444 {
 445         if (deleting) {
 446                 if (delete_file(agent_fd, file, key_only) == -1)
 447                         return -1;
 448         } else {
 449                 if (add_file(agent_fd, file, key_only) == -1)
 450                         return -1;
 451         }
 452         return 0;
 453 }
 454
 455 static void
 456 usage(void)
 457 {
 458         fprintf(stderr, "usage: %s [options] [file ...]\n", __progname);
 459         fprintf(stderr, "Options:\n");
 460         fprintf(stderr, "  -l          List fingerprints of all identities.\n");
 461         fprintf(stderr, "  -E hash     Specify hash algorithm used for fingerprints.\n");
 462         fprintf(stderr, "  -L          List public key parameters of all identities.\n");
 463         fprintf(stderr, "  -k          Load only keys and not certificates.\n");
 464         fprintf(stderr, "  -c          Require confirmation to sign using identities\n");
 465         fprintf(stderr, "  -t life     Set lifetime (in seconds) when adding identities.\n");
 466         fprintf(stderr, "  -d          Delete identity.\n");
 467         fprintf(stderr, "  -D          Delete all identities.\n");
 468         fprintf(stderr, "  -x          Lock agent.\n");
 469         fprintf(stderr, "  -X          Unlock agent.\n");
 470         fprintf(stderr, "  -s pkcs11   Add keys from PKCS#11 provider.\n");
 471         fprintf(stderr, "  -e pkcs11   Remove keys provided by PKCS#11 provider.\n");
 472 }
 473
 474 int
 475 main(int argc, char **argv)
 476 {
 477         extern char *optarg;
 478         extern int optind;
 479         int agent_fd;
 480         char *pkcs11provider = NULL;
 481         int r, i, ch, deleting = 0, ret = 0, key_only = 0;
 482         int xflag = 0, lflag = 0, Dflag = 0;
 483
 484         ssh_malloc_init();      /* must be called before any mallocs */
 485         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 486         sanitise_stdfd();
 487
 488         __progname = ssh_get_progname(argv[0]);
 489         seed_rng();
 490
 491 #ifdef WITH_OPENSSL
 492         OpenSSL_add_all_algorithms();
 493 #endif
 494
 495         setvbuf(stdout, NULL, _IOLBF, 0);
 496
 497         /* First, get a connection to the authentication agent. */
 498         switch (r = ssh_get_authentication_socket(&agent_fd)) {
 499         case 0:
 500                 break;
 501         case SSH_ERR_AGENT_NOT_PRESENT:
 502                 fprintf(stderr, "Could not open a connection to your "
 503                     "authentication agent.\n");
 504                 exit(2);
 505         default:
 506                 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r));
 507                 exit(2);
 508         }
 509
 510         while ((ch = getopt(argc, argv, "klLcdDxXE:e:s:t:")) != -1) {
 511                 switch (ch) {
 512                 case 'E':
 513                         fingerprint_hash = ssh_digest_alg_by_name(optarg);
 514                         if (fingerprint_hash == -1)
 515                                 fatal("Invalid hash algorithm \"%s\"", optarg);
 516                         break;
 517                 case 'k':
 518                         key_only = 1;
 519                         break;
 520                 case 'l':
 521                 case 'L':
 522                         if (lflag != 0)
 523                                 fatal("-%c flag already specified", lflag);
 524                         lflag = ch;
 525                         break;
 526                 case 'x':
 527                 case 'X':
 528                         if (xflag != 0)
 529                                 fatal("-%c flag already specified", xflag);
 530                         xflag = ch;
 531                         break;
 532                 case 'c':
 533                         confirm = 1;
 534                         break;
 535                 case 'd':
 536                         deleting = 1;
 537                         break;
 538                 case 'D':
 539                         Dflag = 1;
 540                         break;
 541                 case 's':
 542                         pkcs11provider = optarg;
 543                         break;
 544                 case 'e':
 545                         deleting = 1;
 546                         pkcs11provider = optarg;
 547                         break;
 548                 case 't':
 549                         if ((lifetime = convtime(optarg)) == -1) {
 550                                 fprintf(stderr, "Invalid lifetime\n");
 551                                 ret = 1;
 552                                 goto done;
 553                         }
 554                         break;
 555                 default:
 556                         usage();
 557                         ret = 1;
 558                         goto done;
 559                 }
 560         }
 561
 562         if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1)
 563                 fatal("Invalid combination of actions");
 564         else if (xflag) {
 565                 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1)
 566                         ret = 1;
 567                 goto done;
 568         } else if (lflag) {
 569                 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1)
 570                         ret = 1;
 571                 goto done;
 572         } else if (Dflag) {
 573                 if (delete_all(agent_fd) == -1)
 574                         ret = 1;
 575                 goto done;
 576         }
 577
 578         argc -= optind;
 579         argv += optind;
 580         if (pkcs11provider != NULL) {
 581                 if (update_card(agent_fd, !deleting, pkcs11provider) == -1)
 582                         ret = 1;
 583                 goto done;
 584         }
 585         if (argc == 0) {
 586                 char buf[PATH_MAX];
 587                 struct passwd *pw;
 588                 struct stat st;
 589                 int count = 0;
 590
 591                 if ((pw = getpwuid(getuid())) == NULL) {
 592                         fprintf(stderr, "No user found with uid %u\n",
 593                             (u_int)getuid());
 594                         ret = 1;
 595                         goto done;
 596                 }
 597
 598                 for (i = 0; default_files[i]; i++) {
 599                         snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir,
 600                             default_files[i]);
 601                         if (stat(buf, &st) < 0)
 602                                 continue;
 603                         if (do_file(agent_fd, deleting, key_only, buf) == -1)
 604                                 ret = 1;
 605                         else
 606                                 count++;
 607                 }
 608                 if (count == 0)
 609                         ret = 1;
 610         } else {
 611                 for (i = 0; i < argc; i++) {
 612                         if (do_file(agent_fd, deleting, key_only,
 613                             argv[i]) == -1)
 614                                 ret = 1;
 615                 }
 616         }
 617         clear_pass();
 618
 619 done:
 620         ssh_close_authentication_socket(agent_fd);
 621         return ret;
 622 }