1 /* $OpenBSD: hostfile.c,v 1.66 2015/05/04 06:10:48 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo (at) cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo (at) cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * Functions for manipulating the known hosts files. 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 * 15 * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved. 16 * Copyright (c) 1999 Niels Provos. 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 41 #include <sys/types.h> 42 #include <sys/stat.h> 43 44 #include <netinet/in.h> 45 46 #include <errno.h> 47 #include <resolv.h> 48 #include <stdarg.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <stdarg.h> 53 #include <unistd.h> 54 55 #include "xmalloc.h" 56 #include "match.h" 57 #include "sshkey.h" 58 #include "hostfile.h" 59 #include "log.h" 60 #include "misc.h" 61 #include "ssherr.h" 62 #include "digest.h" 63 #include "hmac.h" 64 65 struct hostkeys { 66 struct hostkey_entry *entries; 67 u_int num_entries; 68 }; 69 70 /* XXX hmac is too easy to dictionary attack; use bcrypt? */ 71 72 static int 73 extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len) 74 { 75 char *p, *b64salt; 76 u_int b64len; 77 int ret; 78 79 if (l < sizeof(HASH_MAGIC) - 1) { 80 debug2("extract_salt: string too short"); 81 return (-1); 82 } 83 if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { 84 debug2("extract_salt: invalid magic identifier"); 85 return (-1); 86 } 87 s += sizeof(HASH_MAGIC) - 1; 88 l -= sizeof(HASH_MAGIC) - 1; 89 if ((p = memchr(s, HASH_DELIM, l)) == NULL) { 90 debug2("extract_salt: missing salt termination character"); 91 return (-1); 92 } 93 94 b64len = p - s; 95 /* Sanity check */ 96 if (b64len == 0 || b64len > 1024) { 97 debug2("extract_salt: bad encoded salt length %u", b64len); 98 return (-1); 99 } 100 b64salt = xmalloc(1 + b64len); 101 memcpy(b64salt, s, b64len); 102 b64salt[b64len] = '\0'; 103 104 ret = __b64_pton(b64salt, salt, salt_len); 105 free(b64salt); 106 if (ret == -1) { 107 debug2("extract_salt: salt decode error"); 108 return (-1); 109 } 110 if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) { 111 debug2("extract_salt: expected salt len %zd, got %d", 112 ssh_hmac_bytes(SSH_DIGEST_SHA1), ret); 113 return (-1); 114 } 115 116 return (0); 117 } 118 119 char * 120 host_hash(const char *host, const char *name_from_hostfile, u_int src_len) 121 { 122 struct ssh_hmac_ctx *ctx; 123 u_char salt[256], result[256]; 124 char uu_salt[512], uu_result[512]; 125 static char encoded[1024]; 126 u_int i, len; 127 128 len = ssh_digest_bytes(SSH_DIGEST_SHA1); 129 130 if (name_from_hostfile == NULL) { 131 /* Create new salt */ 132 for (i = 0; i < len; i++) 133 salt[i] = arc4random(); 134 } else { 135 /* Extract salt from known host entry */ 136 if (extract_salt(name_from_hostfile, src_len, salt, 137 sizeof(salt)) == -1) 138 return (NULL); 139 } 140 141 if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL || 142 ssh_hmac_init(ctx, salt, len) < 0 || 143 ssh_hmac_update(ctx, host, strlen(host)) < 0 || 144 ssh_hmac_final(ctx, result, sizeof(result))) 145 fatal("%s: ssh_hmac failed", __func__); 146 ssh_hmac_free(ctx); 147 148 if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 || 149 __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1) 150 fatal("%s: __b64_ntop failed", __func__); 151 152 snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt, 153 HASH_DELIM, uu_result); 154 155 return (encoded); 156 } 157 158 /* 159 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the 160 * pointer over the key. Skips any whitespace at the beginning and at end. 161 */ 162 163 int 164 hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret) 165 { 166 char *cp; 167 int r; 168 169 /* Skip leading whitespace. */ 170 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) 171 ; 172 173 if ((r = sshkey_read(ret, &cp)) != 0) 174 return 0; 175 176 /* Skip trailing whitespace. */ 177 for (; *cp == ' ' || *cp == '\t'; cp++) 178 ; 179 180 /* Return results. */ 181 *cpp = cp; 182 if (bitsp != NULL) 183 *bitsp = sshkey_size(ret); 184 return 1; 185 } 186 187 static HostkeyMarker 188 check_markers(char **cpp) 189 { 190 char marker[32], *sp, *cp = *cpp; 191 int ret = MRK_NONE; 192 193 while (*cp == '@') { 194 /* Only one marker is allowed */ 195 if (ret != MRK_NONE) 196 return MRK_ERROR; 197 /* Markers are terminated by whitespace */ 198 if ((sp = strchr(cp, ' ')) == NULL && 199 (sp = strchr(cp, '\t')) == NULL) 200 return MRK_ERROR; 201 /* Extract marker for comparison */ 202 if (sp <= cp + 1 || sp >= cp + sizeof(marker)) 203 return MRK_ERROR; 204 memcpy(marker, cp, sp - cp); 205 marker[sp - cp] = '\0'; 206 if (strcmp(marker, CA_MARKER) == 0) 207 ret = MRK_CA; 208 else if (strcmp(marker, REVOKE_MARKER) == 0) 209 ret = MRK_REVOKE; 210 else 211 return MRK_ERROR; 212 213 /* Skip past marker and any whitespace that follows it */ 214 cp = sp; 215 for (; *cp == ' ' || *cp == '\t'; cp++) 216 ; 217 } 218 *cpp = cp; 219 return ret; 220 } 221 222 struct hostkeys * 223 init_hostkeys(void) 224 { 225 struct hostkeys *ret = xcalloc(1, sizeof(*ret)); 226 227 ret->entries = NULL; 228 return ret; 229 } 230 231 struct load_callback_ctx { 232 const char *host; 233 u_long num_loaded; 234 struct hostkeys *hostkeys; 235 }; 236 237 static int 238 record_hostkey(struct hostkey_foreach_line *l, void *_ctx) 239 { 240 struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx; 241 struct hostkeys *hostkeys = ctx->hostkeys; 242 struct hostkey_entry *tmp; 243 244 if (l->status == HKF_STATUS_INVALID) { 245 /* XXX make this verbose() in the future */ 246 debug("%s:%ld: parse error in hostkeys file", 247 l->path, l->linenum); 248 return 0; 249 } 250 251 debug3("%s: found %skey type %s in file %s:%lu", __func__, 252 l->marker == MRK_NONE ? "" : 253 (l->marker == MRK_CA ? "ca " : "revoked "), 254 sshkey_type(l->key), l->path, l->linenum); 255 if ((tmp = reallocarray(hostkeys->entries, 256 hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL) 257 return SSH_ERR_ALLOC_FAIL; 258 hostkeys->entries = tmp; 259 hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host); 260 hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path); 261 hostkeys->entries[hostkeys->num_entries].line = l->linenum; 262 hostkeys->entries[hostkeys->num_entries].key = l->key; 263 l->key = NULL; /* steal it */ 264 hostkeys->entries[hostkeys->num_entries].marker = l->marker; 265 hostkeys->num_entries++; 266 ctx->num_loaded++; 267 268 return 0; 269 } 270 271 void 272 load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path) 273 { 274 int r; 275 struct load_callback_ctx ctx; 276 277 ctx.host = host; 278 ctx.num_loaded = 0; 279 ctx.hostkeys = hostkeys; 280 281 if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL, 282 HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) { 283 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT) 284 debug("%s: hostkeys_foreach failed for %s: %s", 285 __func__, path, ssh_err(r)); 286 } 287 if (ctx.num_loaded != 0) 288 debug3("%s: loaded %lu keys from %s", __func__, 289 ctx.num_loaded, host); 290 } 291 292 void 293 free_hostkeys(struct hostkeys *hostkeys) 294 { 295 u_int i; 296 297 for (i = 0; i < hostkeys->num_entries; i++) { 298 free(hostkeys->entries[i].host); 299 free(hostkeys->entries[i].file); 300 sshkey_free(hostkeys->entries[i].key); 301 explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries)); 302 } 303 free(hostkeys->entries); 304 explicit_bzero(hostkeys, sizeof(*hostkeys)); 305 free(hostkeys); 306 } 307 308 static int 309 check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k) 310 { 311 int is_cert = sshkey_is_cert(k); 312 u_int i; 313 314 for (i = 0; i < hostkeys->num_entries; i++) { 315 if (hostkeys->entries[i].marker != MRK_REVOKE) 316 continue; 317 if (sshkey_equal_public(k, hostkeys->entries[i].key)) 318 return -1; 319 if (is_cert && 320 sshkey_equal_public(k->cert->signature_key, 321 hostkeys->entries[i].key)) 322 return -1; 323 } 324 return 0; 325 } 326 327 /* 328 * Match keys against a specified key, or look one up by key type. 329 * 330 * If looking for a keytype (key == NULL) and one is found then return 331 * HOST_FOUND, otherwise HOST_NEW. 332 * 333 * If looking for a key (key != NULL): 334 * 1. If the key is a cert and a matching CA is found, return HOST_OK 335 * 2. If the key is not a cert and a matching key is found, return HOST_OK 336 * 3. If no key matches but a key with a different type is found, then 337 * return HOST_CHANGED 338 * 4. If no matching keys are found, then return HOST_NEW. 339 * 340 * Finally, check any found key is not revoked. 341 */ 342 static HostStatus 343 check_hostkeys_by_key_or_type(struct hostkeys *hostkeys, 344 struct sshkey *k, int keytype, const struct hostkey_entry **found) 345 { 346 u_int i; 347 HostStatus end_return = HOST_NEW; 348 int want_cert = sshkey_is_cert(k); 349 HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE; 350 int proto = (k ? k->type : keytype) == KEY_RSA1 ? 1 : 2; 351 352 if (found != NULL) 353 *found = NULL; 354 355 for (i = 0; i < hostkeys->num_entries; i++) { 356 if (proto == 1 && hostkeys->entries[i].key->type != KEY_RSA1) 357 continue; 358 if (proto == 2 && hostkeys->entries[i].key->type == KEY_RSA1) 359 continue; 360 if (hostkeys->entries[i].marker != want_marker) 361 continue; 362 if (k == NULL) { 363 if (hostkeys->entries[i].key->type != keytype) 364 continue; 365 end_return = HOST_FOUND; 366 if (found != NULL) 367 *found = hostkeys->entries + i; 368 k = hostkeys->entries[i].key; 369 break; 370 } 371 if (want_cert) { 372 if (sshkey_equal_public(k->cert->signature_key, 373 hostkeys->entries[i].key)) { 374 /* A matching CA exists */ 375 end_return = HOST_OK; 376 if (found != NULL) 377 *found = hostkeys->entries + i; 378 break; 379 } 380 } else { 381 if (sshkey_equal(k, hostkeys->entries[i].key)) { 382 end_return = HOST_OK; 383 if (found != NULL) 384 *found = hostkeys->entries + i; 385 break; 386 } 387 /* A non-maching key exists */ 388 end_return = HOST_CHANGED; 389 if (found != NULL) 390 *found = hostkeys->entries + i; 391 } 392 } 393 if (check_key_not_revoked(hostkeys, k) != 0) { 394 end_return = HOST_REVOKED; 395 if (found != NULL) 396 *found = NULL; 397 } 398 return end_return; 399 } 400 401 HostStatus 402 check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 403 const struct hostkey_entry **found) 404 { 405 if (key == NULL) 406 fatal("no key to look up"); 407 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found); 408 } 409 410 int 411 lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, 412 const struct hostkey_entry **found) 413 { 414 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, 415 found) == HOST_FOUND); 416 } 417 418 static int 419 write_host_entry(FILE *f, const char *host, const char *ip, 420 const struct sshkey *key, int store_hash) 421 { 422 int r, success = 0; 423 char *hashed_host = NULL; 424 425 if (store_hash) { 426 if ((hashed_host = host_hash(host, NULL, 0)) == NULL) { 427 error("%s: host_hash failed", __func__); 428 return 0; 429 } 430 fprintf(f, "%s ", hashed_host); 431 } else if (ip != NULL) 432 fprintf(f, "%s,%s ", host, ip); 433 else 434 fprintf(f, "%s ", host); 435 436 if ((r = sshkey_write(key, f)) == 0) 437 success = 1; 438 else 439 error("%s: sshkey_write failed: %s", __func__, ssh_err(r)); 440 fputc('\n', f); 441 return success; 442 } 443 444 /* 445 * Appends an entry to the host file. Returns false if the entry could not 446 * be appended. 447 */ 448 int 449 add_host_to_hostfile(const char *filename, const char *host, 450 const struct sshkey *key, int store_hash) 451 { 452 FILE *f; 453 int success; 454 455 if (key == NULL) 456 return 1; /* XXX ? */ 457 f = fopen(filename, "a"); 458 if (!f) 459 return 0; 460 success = write_host_entry(f, host, NULL, key, store_hash); 461 fclose(f); 462 return success; 463 } 464 465 struct host_delete_ctx { 466 FILE *out; 467 int quiet; 468 const char *host; 469 int *skip_keys; /* XXX split for host/ip? might want to ensure both */ 470 struct sshkey * const *keys; 471 size_t nkeys; 472 int modified; 473 }; 474 475 static int 476 host_delete(struct hostkey_foreach_line *l, void *_ctx) 477 { 478 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx; 479 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 480 size_t i; 481 482 if (l->status == HKF_STATUS_MATCHED) { 483 if (l->marker != MRK_NONE) { 484 /* Don't remove CA and revocation lines */ 485 fprintf(ctx->out, "%s\n", l->line); 486 return 0; 487 } 488 489 /* XXX might need a knob for this later */ 490 /* Don't remove RSA1 keys */ 491 if (l->key->type == KEY_RSA1) { 492 fprintf(ctx->out, "%s\n", l->line); 493 return 0; 494 } 495 496 /* 497 * If this line contains one of the keys that we will be 498 * adding later, then don't change it and mark the key for 499 * skipping. 500 */ 501 for (i = 0; i < ctx->nkeys; i++) { 502 if (sshkey_equal(ctx->keys[i], l->key)) { 503 ctx->skip_keys[i] = 1; 504 fprintf(ctx->out, "%s\n", l->line); 505 debug3("%s: %s key already at %s:%ld", __func__, 506 sshkey_type(l->key), l->path, l->linenum); 507 return 0; 508 } 509 } 510 511 /* 512 * Hostname matches and has no CA/revoke marker, delete it 513 * by *not* writing the line to ctx->out. 514 */ 515 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 516 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 517 l->path, l->linenum, sshkey_type(l->key), ctx->host); 518 ctx->modified = 1; 519 return 0; 520 } 521 /* Retain non-matching hosts and invalid lines when deleting */ 522 if (l->status == HKF_STATUS_INVALID) { 523 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 524 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 525 l->path, l->linenum); 526 } 527 fprintf(ctx->out, "%s\n", l->line); 528 return 0; 529 } 530 531 int 532 hostfile_replace_entries(const char *filename, const char *host, const char *ip, 533 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 534 { 535 int r, fd, oerrno = 0; 536 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 537 struct host_delete_ctx ctx; 538 char *fp, *temp = NULL, *back = NULL; 539 mode_t omask; 540 size_t i; 541 542 omask = umask(077); 543 544 memset(&ctx, 0, sizeof(ctx)); 545 ctx.host = host; 546 ctx.quiet = quiet; 547 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL) 548 return SSH_ERR_ALLOC_FAIL; 549 ctx.keys = keys; 550 ctx.nkeys = nkeys; 551 ctx.modified = 0; 552 553 /* 554 * Prepare temporary file for in-place deletion. 555 */ 556 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) < 0 || 557 (r = asprintf(&back, "%s.old", filename)) < 0) { 558 r = SSH_ERR_ALLOC_FAIL; 559 goto fail; 560 } 561 562 if ((fd = mkstemp(temp)) == -1) { 563 oerrno = errno; 564 error("%s: mkstemp: %s", __func__, strerror(oerrno)); 565 r = SSH_ERR_SYSTEM_ERROR; 566 goto fail; 567 } 568 if ((ctx.out = fdopen(fd, "w")) == NULL) { 569 oerrno = errno; 570 close(fd); 571 error("%s: fdopen: %s", __func__, strerror(oerrno)); 572 r = SSH_ERR_SYSTEM_ERROR; 573 goto fail; 574 } 575 576 /* Remove all entries for the specified host from the file */ 577 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 578 HKF_WANT_PARSE_KEY)) != 0) { 579 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 580 goto fail; 581 } 582 583 /* Add the requested keys */ 584 for (i = 0; i < nkeys; i++) { 585 if (ctx.skip_keys[i]) 586 continue; 587 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 588 SSH_FP_DEFAULT)) == NULL) { 589 r = SSH_ERR_ALLOC_FAIL; 590 goto fail; 591 } 592 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s", 593 quiet ? __func__ : "", quiet ? ": " : "", host, filename, 594 sshkey_ssh_name(keys[i]), fp); 595 free(fp); 596 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { 597 r = SSH_ERR_INTERNAL_ERROR; 598 goto fail; 599 } 600 ctx.modified = 1; 601 } 602 fclose(ctx.out); 603 ctx.out = NULL; 604 605 if (ctx.modified) { 606 /* Backup the original file and replace it with the temporary */ 607 if (unlink(back) == -1 && errno != ENOENT) { 608 oerrno = errno; 609 error("%s: unlink %.100s: %s", __func__, 610 back, strerror(errno)); 611 r = SSH_ERR_SYSTEM_ERROR; 612 goto fail; 613 } 614 if (link(filename, back) == -1) { 615 oerrno = errno; 616 error("%s: link %.100s to %.100s: %s", __func__, 617 filename, back, strerror(errno)); 618 r = SSH_ERR_SYSTEM_ERROR; 619 goto fail; 620 } 621 if (rename(temp, filename) == -1) { 622 oerrno = errno; 623 error("%s: rename \"%s\" to \"%s\": %s", __func__, 624 temp, filename, strerror(errno)); 625 r = SSH_ERR_SYSTEM_ERROR; 626 goto fail; 627 } 628 } else { 629 /* No changes made; just delete the temporary file */ 630 if (unlink(temp) != 0) 631 error("%s: unlink \"%s\": %s", __func__, 632 temp, strerror(errno)); 633 } 634 635 /* success */ 636 r = 0; 637 fail: 638 if (temp != NULL && r != 0) 639 unlink(temp); 640 free(temp); 641 free(back); 642 if (ctx.out != NULL) 643 fclose(ctx.out); 644 free(ctx.skip_keys); 645 umask(omask); 646 if (r == SSH_ERR_SYSTEM_ERROR) 647 errno = oerrno; 648 return r; 649 } 650 651 static int 652 match_maybe_hashed(const char *host, const char *names, int *was_hashed) 653 { 654 int hashed = *names == HASH_DELIM; 655 const char *hashed_host; 656 size_t nlen = strlen(names); 657 658 if (was_hashed != NULL) 659 *was_hashed = hashed; 660 if (hashed) { 661 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 662 return -1; 663 return nlen == strlen(hashed_host) && 664 strncmp(hashed_host, names, nlen) == 0; 665 } 666 return match_hostname(host, names) == 1; 667 } 668 669 int 670 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 671 const char *host, const char *ip, u_int options) 672 { 673 FILE *f; 674 char line[8192], oline[8192], ktype[128]; 675 u_long linenum = 0; 676 char *cp, *cp2; 677 u_int kbits; 678 int hashed; 679 int s, r = 0; 680 struct hostkey_foreach_line lineinfo; 681 size_t l; 682 683 memset(&lineinfo, 0, sizeof(lineinfo)); 684 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 685 return SSH_ERR_INVALID_ARGUMENT; 686 if ((f = fopen(path, "r")) == NULL) 687 return SSH_ERR_SYSTEM_ERROR; 688 689 debug3("%s: reading file \"%s\"", __func__, path); 690 while (read_keyfile_line(f, path, line, sizeof(line), &linenum) == 0) { 691 line[strcspn(line, "\n")] = '\0'; 692 strlcpy(oline, line, sizeof(oline)); 693 694 sshkey_free(lineinfo.key); 695 memset(&lineinfo, 0, sizeof(lineinfo)); 696 lineinfo.path = path; 697 lineinfo.linenum = linenum; 698 lineinfo.line = oline; 699 lineinfo.marker = MRK_NONE; 700 lineinfo.status = HKF_STATUS_OK; 701 lineinfo.keytype = KEY_UNSPEC; 702 703 /* Skip any leading whitespace, comments and empty lines. */ 704 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 705 ; 706 if (!*cp || *cp == '#' || *cp == '\n') { 707 if ((options & HKF_WANT_MATCH) == 0) { 708 lineinfo.status = HKF_STATUS_COMMENT; 709 if ((r = callback(&lineinfo, ctx)) != 0) 710 break; 711 } 712 continue; 713 } 714 715 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 716 verbose("%s: invalid marker at %s:%lu", 717 __func__, path, linenum); 718 if ((options & HKF_WANT_MATCH) == 0) 719 goto bad; 720 continue; 721 } 722 723 /* Find the end of the host name portion. */ 724 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 725 ; 726 lineinfo.hosts = cp; 727 *cp2++ = '\0'; 728 729 /* Check if the host name matches. */ 730 if (host != NULL) { 731 if ((s = match_maybe_hashed(host, lineinfo.hosts, 732 &hashed)) == -1) { 733 debug2("%s: %s:%ld: bad host hash \"%.32s\"", 734 __func__, path, linenum, lineinfo.hosts); 735 goto bad; 736 } 737 if (s == 1) { 738 lineinfo.status = HKF_STATUS_MATCHED; 739 lineinfo.match |= HKF_MATCH_HOST | 740 (hashed ? HKF_MATCH_HOST_HASHED : 0); 741 } 742 /* Try matching IP address if supplied */ 743 if (ip != NULL) { 744 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 745 &hashed)) == -1) { 746 debug2("%s: %s:%ld: bad ip hash " 747 "\"%.32s\"", __func__, path, 748 linenum, lineinfo.hosts); 749 goto bad; 750 } 751 if (s == 1) { 752 lineinfo.status = HKF_STATUS_MATCHED; 753 lineinfo.match |= HKF_MATCH_IP | 754 (hashed ? HKF_MATCH_IP_HASHED : 0); 755 } 756 } 757 /* 758 * Skip this line if host matching requested and 759 * neither host nor address matched. 760 */ 761 if ((options & HKF_WANT_MATCH) != 0 && 762 lineinfo.status != HKF_STATUS_MATCHED) 763 continue; 764 } 765 766 /* Got a match. Skip host name and any following whitespace */ 767 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 768 ; 769 if (*cp2 == '\0' || *cp2 == '#') { 770 debug2("%s:%ld: truncated before key type", 771 path, linenum); 772 goto bad; 773 } 774 lineinfo.rawkey = cp = cp2; 775 776 if ((options & HKF_WANT_PARSE_KEY) != 0) { 777 /* 778 * Extract the key from the line. This will skip 779 * any leading whitespace. Ignore badly formatted 780 * lines. 781 */ 782 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 783 error("%s: sshkey_new failed", __func__); 784 r = SSH_ERR_ALLOC_FAIL; 785 break; 786 } 787 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 788 #ifdef WITH_SSH1 789 sshkey_free(lineinfo.key); 790 lineinfo.key = sshkey_new(KEY_RSA1); 791 if (lineinfo.key == NULL) { 792 error("%s: sshkey_new fail", __func__); 793 r = SSH_ERR_ALLOC_FAIL; 794 break; 795 } 796 if (!hostfile_read_key(&cp, &kbits, 797 lineinfo.key)) 798 goto bad; 799 #else 800 goto bad; 801 #endif 802 } 803 lineinfo.keytype = lineinfo.key->type; 804 lineinfo.comment = cp; 805 } else { 806 /* Extract and parse key type */ 807 l = strcspn(lineinfo.rawkey, " \t"); 808 if (l <= 1 || l >= sizeof(ktype) || 809 lineinfo.rawkey[l] == '\0') 810 goto bad; 811 memcpy(ktype, lineinfo.rawkey, l); 812 ktype[l] = '\0'; 813 lineinfo.keytype = sshkey_type_from_name(ktype); 814 815 /* 816 * Assume RSA1 if the first component is a short 817 * decimal number. 818 */ 819 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 820 strspn(ktype, "0123456789") == l) 821 lineinfo.keytype = KEY_RSA1; 822 823 /* 824 * Check that something other than whitespace follows 825 * the key type. This won't catch all corruption, but 826 * it does catch trivial truncation. 827 */ 828 cp2 += l; /* Skip past key type */ 829 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 830 ; 831 if (*cp2 == '\0' || *cp2 == '#') { 832 debug2("%s:%ld: truncated after key type", 833 path, linenum); 834 lineinfo.keytype = KEY_UNSPEC; 835 } 836 if (lineinfo.keytype == KEY_UNSPEC) { 837 bad: 838 sshkey_free(lineinfo.key); 839 lineinfo.key = NULL; 840 lineinfo.status = HKF_STATUS_INVALID; 841 if ((r = callback(&lineinfo, ctx)) != 0) 842 break; 843 continue; 844 } 845 } 846 if ((r = callback(&lineinfo, ctx)) != 0) 847 break; 848 } 849 sshkey_free(lineinfo.key); 850 fclose(f); 851 return r; 852 } 853
