1 /* $OpenBSD: hostfile.c,v 1.67 2016/09/17 18:00:27 tedu 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 * 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 <sys/types.h> 40 #include <sys/stat.h> 41 42 #include <netinet/in.h> 43 44 #include <errno.h> 45 #include <resolv.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <stdarg.h> 50 #include <unistd.h> 51 52 #include "xmalloc.h" 53 #include "match.h" 54 #include "sshkey.h" 55 #include "hostfile.h" 56 #include "log.h" 57 #include "misc.h" 58 #include "ssherr.h" 59 #include "digest.h" 60 #include "hmac.h" 61 62 struct hostkeys { 63 struct hostkey_entry *entries; 64 u_int num_entries; 65 }; 66 67 /* XXX hmac is too easy to dictionary attack; use bcrypt? */ 68 69 static int 70 extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len) 71 { 72 char *p, *b64salt; 73 u_int b64len; 74 int ret; 75 76 if (l < sizeof(HASH_MAGIC) - 1) { 77 debug2("extract_salt: string too short"); 78 return (-1); 79 } 80 if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { 81 debug2("extract_salt: invalid magic identifier"); 82 return (-1); 83 } 84 s += sizeof(HASH_MAGIC) - 1; 85 l -= sizeof(HASH_MAGIC) - 1; 86 if ((p = memchr(s, HASH_DELIM, l)) == NULL) { 87 debug2("extract_salt: missing salt termination character"); 88 return (-1); 89 } 90 91 b64len = p - s; 92 /* Sanity check */ 93 if (b64len == 0 || b64len > 1024) { 94 debug2("extract_salt: bad encoded salt length %u", b64len); 95 return (-1); 96 } 97 b64salt = xmalloc(1 + b64len); 98 memcpy(b64salt, s, b64len); 99 b64salt[b64len] = '\0'; 100 101 ret = __b64_pton(b64salt, salt, salt_len); 102 free(b64salt); 103 if (ret == -1) { 104 debug2("extract_salt: salt decode error"); 105 return (-1); 106 } 107 if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) { 108 debug2("extract_salt: expected salt len %zd, got %d", 109 ssh_hmac_bytes(SSH_DIGEST_SHA1), ret); 110 return (-1); 111 } 112 113 return (0); 114 } 115 116 char * 117 host_hash(const char *host, const char *name_from_hostfile, u_int src_len) 118 { 119 struct ssh_hmac_ctx *ctx; 120 u_char salt[256], result[256]; 121 char uu_salt[512], uu_result[512]; 122 static char encoded[1024]; 123 u_int len; 124 125 len = ssh_digest_bytes(SSH_DIGEST_SHA1); 126 127 if (name_from_hostfile == NULL) { 128 /* Create new salt */ 129 arc4random_buf(salt, len); 130 } else { 131 /* Extract salt from known host entry */ 132 if (extract_salt(name_from_hostfile, src_len, salt, 133 sizeof(salt)) == -1) 134 return (NULL); 135 } 136 137 if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL || 138 ssh_hmac_init(ctx, salt, len) < 0 || 139 ssh_hmac_update(ctx, host, strlen(host)) < 0 || 140 ssh_hmac_final(ctx, result, sizeof(result))) 141 fatal("%s: ssh_hmac failed", __func__); 142 ssh_hmac_free(ctx); 143 144 if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 || 145 __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1) 146 fatal("%s: __b64_ntop failed", __func__); 147 148 snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt, 149 HASH_DELIM, uu_result); 150 151 return (encoded); 152 } 153 154 /* 155 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the 156 * pointer over the key. Skips any whitespace at the beginning and at end. 157 */ 158 159 int 160 hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret) 161 { 162 char *cp; 163 int r; 164 165 /* Skip leading whitespace. */ 166 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++) 167 ; 168 169 if ((r = sshkey_read(ret, &cp)) != 0) 170 return 0; 171 172 /* Skip trailing whitespace. */ 173 for (; *cp == ' ' || *cp == '\t'; cp++) 174 ; 175 176 /* Return results. */ 177 *cpp = cp; 178 if (bitsp != NULL) 179 *bitsp = sshkey_size(ret); 180 return 1; 181 } 182 183 static HostkeyMarker 184 check_markers(char **cpp) 185 { 186 char marker[32], *sp, *cp = *cpp; 187 int ret = MRK_NONE; 188 189 while (*cp == '@') { 190 /* Only one marker is allowed */ 191 if (ret != MRK_NONE) 192 return MRK_ERROR; 193 /* Markers are terminated by whitespace */ 194 if ((sp = strchr(cp, ' ')) == NULL && 195 (sp = strchr(cp, '\t')) == NULL) 196 return MRK_ERROR; 197 /* Extract marker for comparison */ 198 if (sp <= cp + 1 || sp >= cp + sizeof(marker)) 199 return MRK_ERROR; 200 memcpy(marker, cp, sp - cp); 201 marker[sp - cp] = '\0'; 202 if (strcmp(marker, CA_MARKER) == 0) 203 ret = MRK_CA; 204 else if (strcmp(marker, REVOKE_MARKER) == 0) 205 ret = MRK_REVOKE; 206 else 207 return MRK_ERROR; 208 209 /* Skip past marker and any whitespace that follows it */ 210 cp = sp; 211 for (; *cp == ' ' || *cp == '\t'; cp++) 212 ; 213 } 214 *cpp = cp; 215 return ret; 216 } 217 218 struct hostkeys * 219 init_hostkeys(void) 220 { 221 struct hostkeys *ret = xcalloc(1, sizeof(*ret)); 222 223 ret->entries = NULL; 224 return ret; 225 } 226 227 struct load_callback_ctx { 228 const char *host; 229 u_long num_loaded; 230 struct hostkeys *hostkeys; 231 }; 232 233 static int 234 record_hostkey(struct hostkey_foreach_line *l, void *_ctx) 235 { 236 struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx; 237 struct hostkeys *hostkeys = ctx->hostkeys; 238 struct hostkey_entry *tmp; 239 240 if (l->status == HKF_STATUS_INVALID) { 241 /* XXX make this verbose() in the future */ 242 debug("%s:%ld: parse error in hostkeys file", 243 l->path, l->linenum); 244 return 0; 245 } 246 247 debug3("%s: found %skey type %s in file %s:%lu", __func__, 248 l->marker == MRK_NONE ? "" : 249 (l->marker == MRK_CA ? "ca " : "revoked "), 250 sshkey_type(l->key), l->path, l->linenum); 251 if ((tmp = reallocarray(hostkeys->entries, 252 hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL) 253 return SSH_ERR_ALLOC_FAIL; 254 hostkeys->entries = tmp; 255 hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host); 256 hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path); 257 hostkeys->entries[hostkeys->num_entries].line = l->linenum; 258 hostkeys->entries[hostkeys->num_entries].key = l->key; 259 l->key = NULL; /* steal it */ 260 hostkeys->entries[hostkeys->num_entries].marker = l->marker; 261 hostkeys->num_entries++; 262 ctx->num_loaded++; 263 264 return 0; 265 } 266 267 void 268 load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path) 269 { 270 int r; 271 struct load_callback_ctx ctx; 272 273 ctx.host = host; 274 ctx.num_loaded = 0; 275 ctx.hostkeys = hostkeys; 276 277 if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL, 278 HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) { 279 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT) 280 debug("%s: hostkeys_foreach failed for %s: %s", 281 __func__, path, ssh_err(r)); 282 } 283 if (ctx.num_loaded != 0) 284 debug3("%s: loaded %lu keys from %s", __func__, 285 ctx.num_loaded, host); 286 } 287 288 void 289 free_hostkeys(struct hostkeys *hostkeys) 290 { 291 u_int i; 292 293 for (i = 0; i < hostkeys->num_entries; i++) { 294 free(hostkeys->entries[i].host); 295 free(hostkeys->entries[i].file); 296 sshkey_free(hostkeys->entries[i].key); 297 explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries)); 298 } 299 free(hostkeys->entries); 300 explicit_bzero(hostkeys, sizeof(*hostkeys)); 301 free(hostkeys); 302 } 303 304 static int 305 check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k) 306 { 307 int is_cert = sshkey_is_cert(k); 308 u_int i; 309 310 for (i = 0; i < hostkeys->num_entries; i++) { 311 if (hostkeys->entries[i].marker != MRK_REVOKE) 312 continue; 313 if (sshkey_equal_public(k, hostkeys->entries[i].key)) 314 return -1; 315 if (is_cert && 316 sshkey_equal_public(k->cert->signature_key, 317 hostkeys->entries[i].key)) 318 return -1; 319 } 320 return 0; 321 } 322 323 /* 324 * Match keys against a specified key, or look one up by key type. 325 * 326 * If looking for a keytype (key == NULL) and one is found then return 327 * HOST_FOUND, otherwise HOST_NEW. 328 * 329 * If looking for a key (key != NULL): 330 * 1. If the key is a cert and a matching CA is found, return HOST_OK 331 * 2. If the key is not a cert and a matching key is found, return HOST_OK 332 * 3. If no key matches but a key with a different type is found, then 333 * return HOST_CHANGED 334 * 4. If no matching keys are found, then return HOST_NEW. 335 * 336 * Finally, check any found key is not revoked. 337 */ 338 static HostStatus 339 check_hostkeys_by_key_or_type(struct hostkeys *hostkeys, 340 struct sshkey *k, int keytype, const struct hostkey_entry **found) 341 { 342 u_int i; 343 HostStatus end_return = HOST_NEW; 344 int want_cert = sshkey_is_cert(k); 345 HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE; 346 int proto = (k ? k->type : keytype) == KEY_RSA1 ? 1 : 2; 347 348 if (found != NULL) 349 *found = NULL; 350 351 for (i = 0; i < hostkeys->num_entries; i++) { 352 if (proto == 1 && hostkeys->entries[i].key->type != KEY_RSA1) 353 continue; 354 if (proto == 2 && hostkeys->entries[i].key->type == KEY_RSA1) 355 continue; 356 if (hostkeys->entries[i].marker != want_marker) 357 continue; 358 if (k == NULL) { 359 if (hostkeys->entries[i].key->type != keytype) 360 continue; 361 end_return = HOST_FOUND; 362 if (found != NULL) 363 *found = hostkeys->entries + i; 364 k = hostkeys->entries[i].key; 365 break; 366 } 367 if (want_cert) { 368 if (sshkey_equal_public(k->cert->signature_key, 369 hostkeys->entries[i].key)) { 370 /* A matching CA exists */ 371 end_return = HOST_OK; 372 if (found != NULL) 373 *found = hostkeys->entries + i; 374 break; 375 } 376 } else { 377 if (sshkey_equal(k, hostkeys->entries[i].key)) { 378 end_return = HOST_OK; 379 if (found != NULL) 380 *found = hostkeys->entries + i; 381 break; 382 } 383 /* A non-maching key exists */ 384 end_return = HOST_CHANGED; 385 if (found != NULL) 386 *found = hostkeys->entries + i; 387 } 388 } 389 if (check_key_not_revoked(hostkeys, k) != 0) { 390 end_return = HOST_REVOKED; 391 if (found != NULL) 392 *found = NULL; 393 } 394 return end_return; 395 } 396 397 HostStatus 398 check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 399 const struct hostkey_entry **found) 400 { 401 if (key == NULL) 402 fatal("no key to look up"); 403 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found); 404 } 405 406 int 407 lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, 408 const struct hostkey_entry **found) 409 { 410 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, 411 found) == HOST_FOUND); 412 } 413 414 static int 415 write_host_entry(FILE *f, const char *host, const char *ip, 416 const struct sshkey *key, int store_hash) 417 { 418 int r, success = 0; 419 char *hashed_host = NULL; 420 421 if (store_hash) { 422 if ((hashed_host = host_hash(host, NULL, 0)) == NULL) { 423 error("%s: host_hash failed", __func__); 424 return 0; 425 } 426 fprintf(f, "%s ", hashed_host); 427 } else if (ip != NULL) 428 fprintf(f, "%s,%s ", host, ip); 429 else 430 fprintf(f, "%s ", host); 431 432 if ((r = sshkey_write(key, f)) == 0) 433 success = 1; 434 else 435 error("%s: sshkey_write failed: %s", __func__, ssh_err(r)); 436 fputc('\n', f); 437 return success; 438 } 439 440 /* 441 * Appends an entry to the host file. Returns false if the entry could not 442 * be appended. 443 */ 444 int 445 add_host_to_hostfile(const char *filename, const char *host, 446 const struct sshkey *key, int store_hash) 447 { 448 FILE *f; 449 int success; 450 451 if (key == NULL) 452 return 1; /* XXX ? */ 453 f = fopen(filename, "a"); 454 if (!f) 455 return 0; 456 success = write_host_entry(f, host, NULL, key, store_hash); 457 fclose(f); 458 return success; 459 } 460 461 struct host_delete_ctx { 462 FILE *out; 463 int quiet; 464 const char *host; 465 int *skip_keys; /* XXX split for host/ip? might want to ensure both */ 466 struct sshkey * const *keys; 467 size_t nkeys; 468 int modified; 469 }; 470 471 static int 472 host_delete(struct hostkey_foreach_line *l, void *_ctx) 473 { 474 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx; 475 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 476 size_t i; 477 478 if (l->status == HKF_STATUS_MATCHED) { 479 if (l->marker != MRK_NONE) { 480 /* Don't remove CA and revocation lines */ 481 fprintf(ctx->out, "%s\n", l->line); 482 return 0; 483 } 484 485 /* XXX might need a knob for this later */ 486 /* Don't remove RSA1 keys */ 487 if (l->key->type == KEY_RSA1) { 488 fprintf(ctx->out, "%s\n", l->line); 489 return 0; 490 } 491 492 /* 493 * If this line contains one of the keys that we will be 494 * adding later, then don't change it and mark the key for 495 * skipping. 496 */ 497 for (i = 0; i < ctx->nkeys; i++) { 498 if (sshkey_equal(ctx->keys[i], l->key)) { 499 ctx->skip_keys[i] = 1; 500 fprintf(ctx->out, "%s\n", l->line); 501 debug3("%s: %s key already at %s:%ld", __func__, 502 sshkey_type(l->key), l->path, l->linenum); 503 return 0; 504 } 505 } 506 507 /* 508 * Hostname matches and has no CA/revoke marker, delete it 509 * by *not* writing the line to ctx->out. 510 */ 511 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 512 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 513 l->path, l->linenum, sshkey_type(l->key), ctx->host); 514 ctx->modified = 1; 515 return 0; 516 } 517 /* Retain non-matching hosts and invalid lines when deleting */ 518 if (l->status == HKF_STATUS_INVALID) { 519 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 520 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 521 l->path, l->linenum); 522 } 523 fprintf(ctx->out, "%s\n", l->line); 524 return 0; 525 } 526 527 int 528 hostfile_replace_entries(const char *filename, const char *host, const char *ip, 529 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 530 { 531 int r, fd, oerrno = 0; 532 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 533 struct host_delete_ctx ctx; 534 char *fp, *temp = NULL, *back = NULL; 535 mode_t omask; 536 size_t i; 537 538 omask = umask(077); 539 540 memset(&ctx, 0, sizeof(ctx)); 541 ctx.host = host; 542 ctx.quiet = quiet; 543 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL) 544 return SSH_ERR_ALLOC_FAIL; 545 ctx.keys = keys; 546 ctx.nkeys = nkeys; 547 ctx.modified = 0; 548 549 /* 550 * Prepare temporary file for in-place deletion. 551 */ 552 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) < 0 || 553 (r = asprintf(&back, "%s.old", filename)) < 0) { 554 r = SSH_ERR_ALLOC_FAIL; 555 goto fail; 556 } 557 558 if ((fd = mkstemp(temp)) == -1) { 559 oerrno = errno; 560 error("%s: mkstemp: %s", __func__, strerror(oerrno)); 561 r = SSH_ERR_SYSTEM_ERROR; 562 goto fail; 563 } 564 if ((ctx.out = fdopen(fd, "w")) == NULL) { 565 oerrno = errno; 566 close(fd); 567 error("%s: fdopen: %s", __func__, strerror(oerrno)); 568 r = SSH_ERR_SYSTEM_ERROR; 569 goto fail; 570 } 571 572 /* Remove all entries for the specified host from the file */ 573 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 574 HKF_WANT_PARSE_KEY)) != 0) { 575 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 576 goto fail; 577 } 578 579 /* Add the requested keys */ 580 for (i = 0; i < nkeys; i++) { 581 if (ctx.skip_keys[i]) 582 continue; 583 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 584 SSH_FP_DEFAULT)) == NULL) { 585 r = SSH_ERR_ALLOC_FAIL; 586 goto fail; 587 } 588 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s", 589 quiet ? __func__ : "", quiet ? ": " : "", host, filename, 590 sshkey_ssh_name(keys[i]), fp); 591 free(fp); 592 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { 593 r = SSH_ERR_INTERNAL_ERROR; 594 goto fail; 595 } 596 ctx.modified = 1; 597 } 598 fclose(ctx.out); 599 ctx.out = NULL; 600 601 if (ctx.modified) { 602 /* Backup the original file and replace it with the temporary */ 603 if (unlink(back) == -1 && errno != ENOENT) { 604 oerrno = errno; 605 error("%s: unlink %.100s: %s", __func__, 606 back, strerror(errno)); 607 r = SSH_ERR_SYSTEM_ERROR; 608 goto fail; 609 } 610 if (link(filename, back) == -1) { 611 oerrno = errno; 612 error("%s: link %.100s to %.100s: %s", __func__, 613 filename, back, strerror(errno)); 614 r = SSH_ERR_SYSTEM_ERROR; 615 goto fail; 616 } 617 if (rename(temp, filename) == -1) { 618 oerrno = errno; 619 error("%s: rename \"%s\" to \"%s\": %s", __func__, 620 temp, filename, strerror(errno)); 621 r = SSH_ERR_SYSTEM_ERROR; 622 goto fail; 623 } 624 } else { 625 /* No changes made; just delete the temporary file */ 626 if (unlink(temp) != 0) 627 error("%s: unlink \"%s\": %s", __func__, 628 temp, strerror(errno)); 629 } 630 631 /* success */ 632 r = 0; 633 fail: 634 if (temp != NULL && r != 0) 635 unlink(temp); 636 free(temp); 637 free(back); 638 if (ctx.out != NULL) 639 fclose(ctx.out); 640 free(ctx.skip_keys); 641 umask(omask); 642 if (r == SSH_ERR_SYSTEM_ERROR) 643 errno = oerrno; 644 return r; 645 } 646 647 static int 648 match_maybe_hashed(const char *host, const char *names, int *was_hashed) 649 { 650 int hashed = *names == HASH_DELIM; 651 const char *hashed_host; 652 size_t nlen = strlen(names); 653 654 if (was_hashed != NULL) 655 *was_hashed = hashed; 656 if (hashed) { 657 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 658 return -1; 659 return nlen == strlen(hashed_host) && 660 strncmp(hashed_host, names, nlen) == 0; 661 } 662 return match_hostname(host, names) == 1; 663 } 664 665 int 666 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 667 const char *host, const char *ip, u_int options) 668 { 669 FILE *f; 670 char line[8192], oline[8192], ktype[128]; 671 u_long linenum = 0; 672 char *cp, *cp2; 673 u_int kbits; 674 int hashed; 675 int s, r = 0; 676 struct hostkey_foreach_line lineinfo; 677 size_t l; 678 679 memset(&lineinfo, 0, sizeof(lineinfo)); 680 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 681 return SSH_ERR_INVALID_ARGUMENT; 682 if ((f = fopen(path, "r")) == NULL) 683 return SSH_ERR_SYSTEM_ERROR; 684 685 debug3("%s: reading file \"%s\"", __func__, path); 686 while (read_keyfile_line(f, path, line, sizeof(line), &linenum) == 0) { 687 line[strcspn(line, "\n")] = '\0'; 688 strlcpy(oline, line, sizeof(oline)); 689 690 sshkey_free(lineinfo.key); 691 memset(&lineinfo, 0, sizeof(lineinfo)); 692 lineinfo.path = path; 693 lineinfo.linenum = linenum; 694 lineinfo.line = oline; 695 lineinfo.marker = MRK_NONE; 696 lineinfo.status = HKF_STATUS_OK; 697 lineinfo.keytype = KEY_UNSPEC; 698 699 /* Skip any leading whitespace, comments and empty lines. */ 700 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 701 ; 702 if (!*cp || *cp == '#' || *cp == '\n') { 703 if ((options & HKF_WANT_MATCH) == 0) { 704 lineinfo.status = HKF_STATUS_COMMENT; 705 if ((r = callback(&lineinfo, ctx)) != 0) 706 break; 707 } 708 continue; 709 } 710 711 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 712 verbose("%s: invalid marker at %s:%lu", 713 __func__, path, linenum); 714 if ((options & HKF_WANT_MATCH) == 0) 715 goto bad; 716 continue; 717 } 718 719 /* Find the end of the host name portion. */ 720 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 721 ; 722 lineinfo.hosts = cp; 723 *cp2++ = '\0'; 724 725 /* Check if the host name matches. */ 726 if (host != NULL) { 727 if ((s = match_maybe_hashed(host, lineinfo.hosts, 728 &hashed)) == -1) { 729 debug2("%s: %s:%ld: bad host hash \"%.32s\"", 730 __func__, path, linenum, lineinfo.hosts); 731 goto bad; 732 } 733 if (s == 1) { 734 lineinfo.status = HKF_STATUS_MATCHED; 735 lineinfo.match |= HKF_MATCH_HOST | 736 (hashed ? HKF_MATCH_HOST_HASHED : 0); 737 } 738 /* Try matching IP address if supplied */ 739 if (ip != NULL) { 740 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 741 &hashed)) == -1) { 742 debug2("%s: %s:%ld: bad ip hash " 743 "\"%.32s\"", __func__, path, 744 linenum, lineinfo.hosts); 745 goto bad; 746 } 747 if (s == 1) { 748 lineinfo.status = HKF_STATUS_MATCHED; 749 lineinfo.match |= HKF_MATCH_IP | 750 (hashed ? HKF_MATCH_IP_HASHED : 0); 751 } 752 } 753 /* 754 * Skip this line if host matching requested and 755 * neither host nor address matched. 756 */ 757 if ((options & HKF_WANT_MATCH) != 0 && 758 lineinfo.status != HKF_STATUS_MATCHED) 759 continue; 760 } 761 762 /* Got a match. Skip host name and any following whitespace */ 763 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 764 ; 765 if (*cp2 == '\0' || *cp2 == '#') { 766 debug2("%s:%ld: truncated before key type", 767 path, linenum); 768 goto bad; 769 } 770 lineinfo.rawkey = cp = cp2; 771 772 if ((options & HKF_WANT_PARSE_KEY) != 0) { 773 /* 774 * Extract the key from the line. This will skip 775 * any leading whitespace. Ignore badly formatted 776 * lines. 777 */ 778 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 779 error("%s: sshkey_new failed", __func__); 780 r = SSH_ERR_ALLOC_FAIL; 781 break; 782 } 783 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 784 #ifdef WITH_SSH1 785 sshkey_free(lineinfo.key); 786 lineinfo.key = sshkey_new(KEY_RSA1); 787 if (lineinfo.key == NULL) { 788 error("%s: sshkey_new fail", __func__); 789 r = SSH_ERR_ALLOC_FAIL; 790 break; 791 } 792 if (!hostfile_read_key(&cp, &kbits, 793 lineinfo.key)) 794 goto bad; 795 #else 796 goto bad; 797 #endif 798 } 799 lineinfo.keytype = lineinfo.key->type; 800 lineinfo.comment = cp; 801 } else { 802 /* Extract and parse key type */ 803 l = strcspn(lineinfo.rawkey, " \t"); 804 if (l <= 1 || l >= sizeof(ktype) || 805 lineinfo.rawkey[l] == '\0') 806 goto bad; 807 memcpy(ktype, lineinfo.rawkey, l); 808 ktype[l] = '\0'; 809 lineinfo.keytype = sshkey_type_from_name(ktype); 810 811 /* 812 * Assume RSA1 if the first component is a short 813 * decimal number. 814 */ 815 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 816 strspn(ktype, "0123456789") == l) 817 lineinfo.keytype = KEY_RSA1; 818 819 /* 820 * Check that something other than whitespace follows 821 * the key type. This won't catch all corruption, but 822 * it does catch trivial truncation. 823 */ 824 cp2 += l; /* Skip past key type */ 825 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 826 ; 827 if (*cp2 == '\0' || *cp2 == '#') { 828 debug2("%s:%ld: truncated after key type", 829 path, linenum); 830 lineinfo.keytype = KEY_UNSPEC; 831 } 832 if (lineinfo.keytype == KEY_UNSPEC) { 833 bad: 834 sshkey_free(lineinfo.key); 835 lineinfo.key = NULL; 836 lineinfo.status = HKF_STATUS_INVALID; 837 if ((r = callback(&lineinfo, ctx)) != 0) 838 break; 839 continue; 840 } 841 } 842 if ((r = callback(&lineinfo, ctx)) != 0) 843 break; 844 } 845 sshkey_free(lineinfo.key); 846 fclose(f); 847 return r; 848 } 849