crypto/openssh/ssh-add.c

   1 /* $OpenBSD: ssh-add.c,v 1.134 2017/08/29 09:42:29 dlg 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 "log.h"
  59 #include "sshkey.h"
  60 #include "sshbuf.h"
  61 #include "authfd.h"
  62 #include "authfile.h"
  63 #include "pathnames.h"
  64 #include "misc.h"
  65 #include "ssherr.h"
  66 #include "digest.h"
  67
  68 /* argv0 */
  69 extern char *__progname;
  70
  71 /* Default files to add */
  72 static char *default_files[] = {
  73 #ifdef WITH_OPENSSL
  74         _PATH_SSH_CLIENT_ID_RSA,
  75         _PATH_SSH_CLIENT_ID_DSA,
  76 #ifdef OPENSSL_HAS_ECC
  77         _PATH_SSH_CLIENT_ID_ECDSA,
  78 #endif
  79 #endif /* WITH_OPENSSL */
  80         _PATH_SSH_CLIENT_ID_ED25519,
  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, int qflag)
 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                 if (!qflag) {
 117                         fprintf(stderr, "Identity removed: %s (%s)\n",
 118                             filename, comment);
 119                 }
 120                 ret = 0;
 121         } else
 122                 fprintf(stderr, "Could not remove identity \"%s\": %s\n",
 123                     filename, ssh_err(r));
 124
 125         if (key_only)
 126                 goto out;
 127
 128         /* Now try to delete the corresponding certificate too */
 129         free(comment);
 130         comment = NULL;
 131         xasprintf(&certpath, "%s-cert.pub", filename);
 132         if ((r = sshkey_load_public(certpath, &cert, &comment)) != 0) {
 133                 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
 134                         error("Failed to load certificate \"%s\": %s",
 135                             certpath, ssh_err(r));
 136                 goto out;
 137         }
 138
 139         if (!sshkey_equal_public(cert, public))
 140                 fatal("Certificate %s does not match private key %s",
 141                     certpath, filename);
 142
 143         if ((r = ssh_remove_identity(agent_fd, cert)) == 0) {
 144                 if (!qflag) {
 145                         fprintf(stderr, "Identity removed: %s (%s)\n",
 146                             certpath, comment);
 147                 }
 148                 ret = 0;
 149         } else
 150                 fprintf(stderr, "Could not remove identity \"%s\": %s\n",
 151                     certpath, ssh_err(r));
 152
 153  out:
 154         sshkey_free(cert);
 155         sshkey_free(public);
 156         free(certpath);
 157         free(comment);
 158
 159         return ret;
 160 }
 161
 162 /* Send a request to remove all identities. */
 163 static int
 164 delete_all(int agent_fd)
 165 {
 166         int ret = -1;
 167
 168         /*
 169          * Since the agent might be forwarded, old or non-OpenSSH, when asked
 170          * to remove all keys, attempt to remove both protocol v.1 and v.2
 171          * keys.
 172          */
 173         if (ssh_remove_all_identities(agent_fd, 2) == 0)
 174                 ret = 0;
 175         /* ignore error-code for ssh1 */
 176         ssh_remove_all_identities(agent_fd, 1);
 177
 178         if (ret == 0)
 179                 fprintf(stderr, "All identities removed.\n");
 180         else
 181                 fprintf(stderr, "Failed to remove all identities.\n");
 182
 183         return ret;
 184 }
 185
 186 static int
 187 add_file(int agent_fd, const char *filename, int key_only, int qflag)
 188 {
 189         struct sshkey *private, *cert;
 190         char *comment = NULL;
 191         char msg[1024], *certpath = NULL;
 192         int r, fd, ret = -1;
 193         struct sshbuf *keyblob;
 194
 195         if (strcmp(filename, "-") == 0) {
 196                 fd = STDIN_FILENO;
 197                 filename = "(stdin)";
 198         } else if ((fd = open(filename, O_RDONLY)) < 0) {
 199                 perror(filename);
 200                 return -1;
 201         }
 202
 203         /*
 204          * Since we'll try to load a keyfile multiple times, permission errors
 205          * will occur multiple times, so check perms first and bail if wrong.
 206          */
 207         if (fd != STDIN_FILENO) {
 208                 if (sshkey_perm_ok(fd, filename) != 0) {
 209                         close(fd);
 210                         return -1;
 211                 }
 212         }
 213         if ((keyblob = sshbuf_new()) == NULL)
 214                 fatal("%s: sshbuf_new failed", __func__);
 215         if ((r = sshkey_load_file(fd, keyblob)) != 0) {
 216                 fprintf(stderr, "Error loading key \"%s\": %s\n",
 217                     filename, ssh_err(r));
 218                 sshbuf_free(keyblob);
 219                 close(fd);
 220                 return -1;
 221         }
 222         close(fd);
 223
 224         /* At first, try empty passphrase */
 225         if ((r = sshkey_parse_private_fileblob(keyblob, "", &private,
 226             &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
 227                 fprintf(stderr, "Error loading key \"%s\": %s\n",
 228                     filename, ssh_err(r));
 229                 goto fail_load;
 230         }
 231         /* try last */
 232         if (private == NULL && pass != NULL) {
 233                 if ((r = sshkey_parse_private_fileblob(keyblob, pass, &private,
 234                     &comment)) != 0 && r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
 235                         fprintf(stderr, "Error loading key \"%s\": %s\n",
 236                             filename, ssh_err(r));
 237                         goto fail_load;
 238                 }
 239         }
 240         if (private == NULL) {
 241                 /* clear passphrase since it did not work */
 242                 clear_pass();
 243                 snprintf(msg, sizeof msg, "Enter passphrase for %s%s: ",
 244                     filename, confirm ? " (will confirm each use)" : "");
 245                 for (;;) {
 246                         pass = read_passphrase(msg, RP_ALLOW_STDIN);
 247                         if (strcmp(pass, "") == 0)
 248                                 goto fail_load;
 249                         if ((r = sshkey_parse_private_fileblob(keyblob, pass,
 250                             &private, &comment)) == 0)
 251                                 break;
 252                         else if (r != SSH_ERR_KEY_WRONG_PASSPHRASE) {
 253                                 fprintf(stderr,
 254                                     "Error loading key \"%s\": %s\n",
 255                                     filename, ssh_err(r));
 256  fail_load:
 257                                 clear_pass();
 258                                 sshbuf_free(keyblob);
 259                                 return -1;
 260                         }
 261                         clear_pass();
 262                         snprintf(msg, sizeof msg,
 263                             "Bad passphrase, try again for %s%s: ", filename,
 264                             confirm ? " (will confirm each use)" : "");
 265                 }
 266         }
 267         if (comment == NULL || *comment == '\0')
 268                 comment = xstrdup(filename);
 269         sshbuf_free(keyblob);
 270
 271         if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
 272             lifetime, confirm)) == 0) {
 273                 fprintf(stderr, "Identity added: %s (%s)\n", filename, comment);
 274                 ret = 0;
 275                 if (lifetime != 0)
 276                         fprintf(stderr,
 277                             "Lifetime set to %d seconds\n", lifetime);
 278                 if (confirm != 0)
 279                         fprintf(stderr,
 280                             "The user must confirm each use of the key\n");
 281         } else {
 282                 fprintf(stderr, "Could not add identity \"%s\": %s\n",
 283                     filename, ssh_err(r));
 284         }
 285
 286         /* Skip trying to load the cert if requested */
 287         if (key_only)
 288                 goto out;
 289
 290         /* Now try to add the certificate flavour too */
 291         xasprintf(&certpath, "%s-cert.pub", filename);
 292         if ((r = sshkey_load_public(certpath, &cert, NULL)) != 0) {
 293                 if (r != SSH_ERR_SYSTEM_ERROR || errno != ENOENT)
 294                         error("Failed to load certificate \"%s\": %s",
 295                             certpath, ssh_err(r));
 296                 goto out;
 297         }
 298
 299         if (!sshkey_equal_public(cert, private)) {
 300                 error("Certificate %s does not match private key %s",
 301                     certpath, filename);
 302                 sshkey_free(cert);
 303                 goto out;
 304         }
 305
 306         /* Graft with private bits */
 307         if ((r = sshkey_to_certified(private)) != 0) {
 308                 error("%s: sshkey_to_certified: %s", __func__, ssh_err(r));
 309                 sshkey_free(cert);
 310                 goto out;
 311         }
 312         if ((r = sshkey_cert_copy(cert, private)) != 0) {
 313                 error("%s: sshkey_cert_copy: %s", __func__, ssh_err(r));
 314                 sshkey_free(cert);
 315                 goto out;
 316         }
 317         sshkey_free(cert);
 318
 319         if ((r = ssh_add_identity_constrained(agent_fd, private, comment,
 320             lifetime, confirm)) != 0) {
 321                 error("Certificate %s (%s) add failed: %s", certpath,
 322                     private->cert->key_id, ssh_err(r));
 323                 goto out;
 324         }
 325         fprintf(stderr, "Certificate added: %s (%s)\n", certpath,
 326             private->cert->key_id);
 327         if (lifetime != 0)
 328                 fprintf(stderr, "Lifetime set to %d seconds\n", lifetime);
 329         if (confirm != 0)
 330                 fprintf(stderr, "The user must confirm each use of the key\n");
 331  out:
 332         free(certpath);
 333         free(comment);
 334         sshkey_free(private);
 335
 336         return ret;
 337 }
 338
 339 static int
 340 update_card(int agent_fd, int add, const char *id)
 341 {
 342         char *pin = NULL;
 343         int r, ret = -1;
 344
 345         if (add) {
 346                 if ((pin = read_passphrase("Enter passphrase for PKCS#11: ",
 347                     RP_ALLOW_STDIN)) == NULL)
 348                         return -1;
 349         }
 350
 351         if ((r = ssh_update_card(agent_fd, add, id, pin == NULL ? "" : pin,
 352             lifetime, confirm)) == 0) {
 353                 fprintf(stderr, "Card %s: %s\n",
 354                     add ? "added" : "removed", id);
 355                 ret = 0;
 356         } else {
 357                 fprintf(stderr, "Could not %s card \"%s\": %s\n",
 358                     add ? "add" : "remove", id, ssh_err(r));
 359                 ret = -1;
 360         }
 361         free(pin);
 362         return ret;
 363 }
 364
 365 static int
 366 list_identities(int agent_fd, int do_fp)
 367 {
 368         char *fp;
 369         int r;
 370         struct ssh_identitylist *idlist;
 371         size_t i;
 372
 373         if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) {
 374                 if (r != SSH_ERR_AGENT_NO_IDENTITIES)
 375                         fprintf(stderr, "error fetching identities: %s\n",
 376                             ssh_err(r));
 377                 else
 378                         printf("The agent has no identities.\n");
 379                 return -1;
 380         }
 381         for (i = 0; i < idlist->nkeys; i++) {
 382                 if (do_fp) {
 383                         fp = sshkey_fingerprint(idlist->keys[i],
 384                             fingerprint_hash, SSH_FP_DEFAULT);
 385                         printf("%u %s %s (%s)\n", sshkey_size(idlist->keys[i]),
 386                             fp == NULL ? "(null)" : fp, idlist->comments[i],
 387                             sshkey_type(idlist->keys[i]));
 388                         free(fp);
 389                 } else {
 390                         if ((r = sshkey_write(idlist->keys[i], stdout)) != 0) {
 391                                 fprintf(stderr, "sshkey_write: %s\n",
 392                                     ssh_err(r));
 393                                 continue;
 394                         }
 395                         fprintf(stdout, " %s\n", idlist->comments[i]);
 396                 }
 397         }
 398         ssh_free_identitylist(idlist);
 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, int qflag)
 436 {
 437         if (deleting) {
 438                 if (delete_file(agent_fd, file, key_only, qflag) == -1)
 439                         return -1;
 440         } else {
 441                 if (add_file(agent_fd, file, key_only, qflag) == -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         fprintf(stderr, "  -q          Be quiet after a successful operation.\n");
 465 }
 466
 467 int
 468 main(int argc, char **argv)
 469 {
 470         extern char *optarg;
 471         extern int optind;
 472         int agent_fd;
 473         char *pkcs11provider = NULL;
 474         int r, i, ch, deleting = 0, ret = 0, key_only = 0;
 475         int xflag = 0, lflag = 0, Dflag = 0, qflag = 0;
 476
 477         ssh_malloc_init();      /* must be called before any mallocs */
 478         /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
 479         sanitise_stdfd();
 480
 481         __progname = ssh_get_progname(argv[0]);
 482         seed_rng();
 483
 484 #ifdef WITH_OPENSSL
 485         OpenSSL_add_all_algorithms();
 486 #endif
 487
 488         setvbuf(stdout, NULL, _IOLBF, 0);
 489
 490         /* First, get a connection to the authentication agent. */
 491         switch (r = ssh_get_authentication_socket(&agent_fd)) {
 492         case 0:
 493                 break;
 494         case SSH_ERR_AGENT_NOT_PRESENT:
 495                 fprintf(stderr, "Could not open a connection to your "
 496                     "authentication agent.\n");
 497                 exit(2);
 498         default:
 499                 fprintf(stderr, "Error connecting to agent: %s\n", ssh_err(r));
 500                 exit(2);
 501         }
 502
 503         while ((ch = getopt(argc, argv, "klLcdDxXE:e:qs:t:")) != -1) {
 504                 switch (ch) {
 505                 case 'E':
 506                         fingerprint_hash = ssh_digest_alg_by_name(optarg);
 507                         if (fingerprint_hash == -1)
 508                                 fatal("Invalid hash algorithm \"%s\"", optarg);
 509                         break;
 510                 case 'k':
 511                         key_only = 1;
 512                         break;
 513                 case 'l':
 514                 case 'L':
 515                         if (lflag != 0)
 516                                 fatal("-%c flag already specified", lflag);
 517                         lflag = ch;
 518                         break;
 519                 case 'x':
 520                 case 'X':
 521                         if (xflag != 0)
 522                                 fatal("-%c flag already specified", xflag);
 523                         xflag = ch;
 524                         break;
 525                 case 'c':
 526                         confirm = 1;
 527                         break;
 528                 case 'd':
 529                         deleting = 1;
 530                         break;
 531                 case 'D':
 532                         Dflag = 1;
 533                         break;
 534                 case 's':
 535                         pkcs11provider = optarg;
 536                         break;
 537                 case 'e':
 538                         deleting = 1;
 539                         pkcs11provider = optarg;
 540                         break;
 541                 case 't':
 542                         if ((lifetime = convtime(optarg)) == -1) {
 543                                 fprintf(stderr, "Invalid lifetime\n");
 544                                 ret = 1;
 545                                 goto done;
 546                         }
 547                         break;
 548                 case 'q':
 549                         qflag = 1;
 550                         break;
 551                 default:
 552                         usage();
 553                         ret = 1;
 554                         goto done;
 555                 }
 556         }
 557
 558         if ((xflag != 0) + (lflag != 0) + (Dflag != 0) > 1)
 559                 fatal("Invalid combination of actions");
 560         else if (xflag) {
 561                 if (lock_agent(agent_fd, xflag == 'x' ? 1 : 0) == -1)
 562                         ret = 1;
 563                 goto done;
 564         } else if (lflag) {
 565                 if (list_identities(agent_fd, lflag == 'l' ? 1 : 0) == -1)
 566                         ret = 1;
 567                 goto done;
 568         } else if (Dflag) {
 569                 if (delete_all(agent_fd) == -1)
 570                         ret = 1;
 571                 goto done;
 572         }
 573
 574         argc -= optind;
 575         argv += optind;
 576         if (pkcs11provider != NULL) {
 577                 if (update_card(agent_fd, !deleting, pkcs11provider) == -1)
 578                         ret = 1;
 579                 goto done;
 580         }
 581         if (argc == 0) {
 582                 char buf[PATH_MAX];
 583                 struct passwd *pw;
 584                 struct stat st;
 585                 int count = 0;
 586
 587                 if ((pw = getpwuid(getuid())) == NULL) {
 588                         fprintf(stderr, "No user found with uid %u\n",
 589                             (u_int)getuid());
 590                         ret = 1;
 591                         goto done;
 592                 }
 593
 594                 for (i = 0; default_files[i]; i++) {
 595                         snprintf(buf, sizeof(buf), "%s/%s", pw->pw_dir,
 596                             default_files[i]);
 597                         if (stat(buf, &st) < 0)
 598                                 continue;
 599                         if (do_file(agent_fd, deleting, key_only, buf,
 600                             qflag) == -1)
 601                                 ret = 1;
 602                         else
 603                                 count++;
 604                 }
 605                 if (count == 0)
 606                         ret = 1;
 607         } else {
 608                 for (i = 0; i < argc; i++) {
 609                         if (do_file(agent_fd, deleting, key_only,
 610                             argv[i], qflag) == -1)
 611                                 ret = 1;
 612                 }
 613         }
 614         clear_pass();
 615
 616 done:
 617         ssh_close_authentication_socket(agent_fd);
 618         return ret;
 619 }