hostfile.c revision 1.11
1/* $NetBSD: hostfile.c,v 1.11 2017/10/07 19:39:19 christos Exp $ */ 2/* $OpenBSD: hostfile.c,v 1.71 2017/05/31 09:15:42 deraadt Exp $ */ 3/* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * Functions for manipulating the known hosts files. 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * 16 * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved. 17 * Copyright (c) 1999 Niels Provos. All rights reserved. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notice, this list of conditions and the following disclaimer. 24 * 2. Redistributions in binary form must reproduce the above copyright 25 * notice, this list of conditions and the following disclaimer in the 26 * documentation and/or other materials provided with the distribution. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 29 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 30 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 31 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 33 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 34 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 35 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 36 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 37 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40#include "includes.h" 41__RCSID("$NetBSD: hostfile.c,v 1.11 2017/10/07 19:39:19 christos Exp $"); 42#include <sys/types.h> 43#include <sys/stat.h> 44 45#include <netinet/in.h> 46 47#include <errno.h> 48#include <resolv.h> 49#include <stdio.h> 50#include <stdlib.h> 51#include <string.h> 52#include <stdarg.h> 53#include <time.h> 54#include <unistd.h> 55 56#include "xmalloc.h" 57#include "match.h" 58#include "sshkey.h" 59#include "hostfile.h" 60#include "log.h" 61#include "misc.h" 62#include "ssherr.h" 63#include "digest.h" 64#include "hmac.h" 65 66struct hostkeys { 67 struct hostkey_entry *entries; 68 u_int num_entries; 69}; 70 71/* XXX hmac is too easy to dictionary attack; use bcrypt? */ 72 73static int 74extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len) 75{ 76 char *p, *b64salt; 77 u_int b64len; 78 int ret; 79 80 if (l < sizeof(HASH_MAGIC) - 1) { 81 debug2("extract_salt: string too short"); 82 return (-1); 83 } 84 if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) { 85 debug2("extract_salt: invalid magic identifier"); 86 return (-1); 87 } 88 s += sizeof(HASH_MAGIC) - 1; 89 l -= sizeof(HASH_MAGIC) - 1; 90 if ((p = memchr(s, HASH_DELIM, l)) == NULL) { 91 debug2("extract_salt: missing salt termination character"); 92 return (-1); 93 } 94 95 b64len = p - s; 96 /* Sanity check */ 97 if (b64len == 0 || b64len > 1024) { 98 debug2("extract_salt: bad encoded salt length %u", b64len); 99 return (-1); 100 } 101 b64salt = xmalloc(1 + b64len); 102 memcpy(b64salt, s, b64len); 103 b64salt[b64len] = '\0'; 104 105 ret = __b64_pton(b64salt, salt, salt_len); 106 free(b64salt); 107 if (ret == -1) { 108 debug2("extract_salt: salt decode error"); 109 return (-1); 110 } 111 if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) { 112 debug2("extract_salt: expected salt len %zd, got %d", 113 ssh_hmac_bytes(SSH_DIGEST_SHA1), ret); 114 return (-1); 115 } 116 117 return (0); 118} 119 120char * 121host_hash(const char *host, const char *name_from_hostfile, u_int src_len) 122{ 123 struct ssh_hmac_ctx *ctx; 124 u_char salt[256], result[256]; 125 char uu_salt[512], uu_result[512]; 126 static char encoded[1024]; 127 u_int len; 128 129 len = ssh_digest_bytes(SSH_DIGEST_SHA1); 130 131 if (name_from_hostfile == NULL) { 132 /* Create new salt */ 133 arc4random_buf(salt, len); 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 163int 164hostfile_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 187static HostkeyMarker 188check_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 222struct hostkeys * 223init_hostkeys(void) 224{ 225 struct hostkeys *ret = xcalloc(1, sizeof(*ret)); 226 227 ret->entries = NULL; 228 return ret; 229} 230 231struct load_callback_ctx { 232 const char *host; 233 u_long num_loaded; 234 struct hostkeys *hostkeys; 235}; 236 237static int 238record_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 = recallocarray(hostkeys->entries, hostkeys->num_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 271void 272load_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 292void 293free_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 308static int 309check_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 */ 342static HostStatus 343check_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; 350 351 if (found != NULL) 352 *found = NULL; 353 354 for (i = 0; i < hostkeys->num_entries; i++) { 355 if (hostkeys->entries[i].marker != want_marker) 356 continue; 357 if (k == NULL) { 358 if (hostkeys->entries[i].key->type != keytype) 359 continue; 360 end_return = HOST_FOUND; 361 if (found != NULL) 362 *found = hostkeys->entries + i; 363 k = hostkeys->entries[i].key; 364 break; 365 } 366 if (want_cert) { 367 if (sshkey_equal_public(k->cert->signature_key, 368 hostkeys->entries[i].key)) { 369 /* A matching CA exists */ 370 end_return = HOST_OK; 371 if (found != NULL) 372 *found = hostkeys->entries + i; 373 break; 374 } 375 } else { 376 if (sshkey_equal(k, hostkeys->entries[i].key)) { 377 end_return = HOST_OK; 378 if (found != NULL) 379 *found = hostkeys->entries + i; 380 break; 381 } 382 /* A non-maching key exists */ 383 end_return = HOST_CHANGED; 384 if (found != NULL) 385 *found = hostkeys->entries + i; 386 } 387 } 388 if (check_key_not_revoked(hostkeys, k) != 0) { 389 end_return = HOST_REVOKED; 390 if (found != NULL) 391 *found = NULL; 392 } 393 return end_return; 394} 395 396HostStatus 397check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key, 398 const struct hostkey_entry **found) 399{ 400 if (key == NULL) 401 fatal("no key to look up"); 402 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found); 403} 404 405int 406lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, 407 const struct hostkey_entry **found) 408{ 409 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, 410 found) == HOST_FOUND); 411} 412 413static int 414write_host_entry(FILE *f, const char *host, const char *ip, 415 const struct sshkey *key, int store_hash) 416{ 417 int r, success = 0; 418 char *hashed_host = NULL, *lhost; 419 420 lhost = xstrdup(host); 421 lowercase(lhost); 422 423 if (store_hash) { 424 if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) { 425 error("%s: host_hash failed", __func__); 426 free(lhost); 427 return 0; 428 } 429 fprintf(f, "%s ", hashed_host); 430 } else if (ip != NULL) 431 fprintf(f, "%s,%s ", lhost, ip); 432 else { 433 fprintf(f, "%s ", lhost); 434 } 435 free(lhost); 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 */ 448int 449add_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 465struct 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 475static int 476host_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 /* 490 * If this line contains one of the keys that we will be 491 * adding later, then don't change it and mark the key for 492 * skipping. 493 */ 494 for (i = 0; i < ctx->nkeys; i++) { 495 if (sshkey_equal(ctx->keys[i], l->key)) { 496 ctx->skip_keys[i] = 1; 497 fprintf(ctx->out, "%s\n", l->line); 498 debug3("%s: %s key already at %s:%ld", __func__, 499 sshkey_type(l->key), l->path, l->linenum); 500 return 0; 501 } 502 } 503 504 /* 505 * Hostname matches and has no CA/revoke marker, delete it 506 * by *not* writing the line to ctx->out. 507 */ 508 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s", 509 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 510 l->path, l->linenum, sshkey_type(l->key), ctx->host); 511 ctx->modified = 1; 512 return 0; 513 } 514 /* Retain non-matching hosts and invalid lines when deleting */ 515 if (l->status == HKF_STATUS_INVALID) { 516 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry", 517 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "", 518 l->path, l->linenum); 519 } 520 fprintf(ctx->out, "%s\n", l->line); 521 return 0; 522} 523 524int 525hostfile_replace_entries(const char *filename, const char *host, const char *ip, 526 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg) 527{ 528 int r, fd, oerrno = 0; 529 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE; 530 struct host_delete_ctx ctx; 531 char *fp, *temp = NULL, *back = NULL; 532 mode_t omask; 533 size_t i; 534 535 omask = umask(077); 536 537 memset(&ctx, 0, sizeof(ctx)); 538 ctx.host = host; 539 ctx.quiet = quiet; 540 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL) 541 return SSH_ERR_ALLOC_FAIL; 542 ctx.keys = keys; 543 ctx.nkeys = nkeys; 544 ctx.modified = 0; 545 546 /* 547 * Prepare temporary file for in-place deletion. 548 */ 549 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) < 0 || 550 (r = asprintf(&back, "%s.old", filename)) < 0) { 551 r = SSH_ERR_ALLOC_FAIL; 552 goto fail; 553 } 554 555 if ((fd = mkstemp(temp)) == -1) { 556 oerrno = errno; 557 error("%s: mkstemp: %s", __func__, strerror(oerrno)); 558 r = SSH_ERR_SYSTEM_ERROR; 559 goto fail; 560 } 561 if ((ctx.out = fdopen(fd, "w")) == NULL) { 562 oerrno = errno; 563 close(fd); 564 error("%s: fdopen: %s", __func__, strerror(oerrno)); 565 r = SSH_ERR_SYSTEM_ERROR; 566 goto fail; 567 } 568 569 /* Remove all entries for the specified host from the file */ 570 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip, 571 HKF_WANT_PARSE_KEY)) != 0) { 572 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 573 goto fail; 574 } 575 576 /* Add the requested keys */ 577 for (i = 0; i < nkeys; i++) { 578 if (ctx.skip_keys[i]) 579 continue; 580 if ((fp = sshkey_fingerprint(keys[i], hash_alg, 581 SSH_FP_DEFAULT)) == NULL) { 582 r = SSH_ERR_ALLOC_FAIL; 583 goto fail; 584 } 585 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s", 586 quiet ? __func__ : "", quiet ? ": " : "", host, filename, 587 sshkey_ssh_name(keys[i]), fp); 588 free(fp); 589 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) { 590 r = SSH_ERR_INTERNAL_ERROR; 591 goto fail; 592 } 593 ctx.modified = 1; 594 } 595 fclose(ctx.out); 596 ctx.out = NULL; 597 598 if (ctx.modified) { 599 /* Backup the original file and replace it with the temporary */ 600 if (unlink(back) == -1 && errno != ENOENT) { 601 oerrno = errno; 602 error("%s: unlink %.100s: %s", __func__, 603 back, strerror(errno)); 604 r = SSH_ERR_SYSTEM_ERROR; 605 goto fail; 606 } 607 if (link(filename, back) == -1) { 608 oerrno = errno; 609 error("%s: link %.100s to %.100s: %s", __func__, 610 filename, back, strerror(errno)); 611 r = SSH_ERR_SYSTEM_ERROR; 612 goto fail; 613 } 614 if (rename(temp, filename) == -1) { 615 oerrno = errno; 616 error("%s: rename \"%s\" to \"%s\": %s", __func__, 617 temp, filename, strerror(errno)); 618 r = SSH_ERR_SYSTEM_ERROR; 619 goto fail; 620 } 621 } else { 622 /* No changes made; just delete the temporary file */ 623 if (unlink(temp) != 0) 624 error("%s: unlink \"%s\": %s", __func__, 625 temp, strerror(errno)); 626 } 627 628 /* success */ 629 r = 0; 630 fail: 631 if (temp != NULL && r != 0) 632 unlink(temp); 633 free(temp); 634 free(back); 635 if (ctx.out != NULL) 636 fclose(ctx.out); 637 free(ctx.skip_keys); 638 umask(omask); 639 if (r == SSH_ERR_SYSTEM_ERROR) 640 errno = oerrno; 641 return r; 642} 643 644static int 645match_maybe_hashed(const char *host, const char *names, int *was_hashed) 646{ 647 int hashed = *names == HASH_DELIM; 648 const char *hashed_host; 649 size_t nlen = strlen(names); 650 651 if (was_hashed != NULL) 652 *was_hashed = hashed; 653 if (hashed) { 654 if ((hashed_host = host_hash(host, names, nlen)) == NULL) 655 return -1; 656 return nlen == strlen(hashed_host) && 657 strncmp(hashed_host, names, nlen) == 0; 658 } 659 return match_hostname(host, names) == 1; 660} 661 662int 663hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx, 664 const char *host, const char *ip, u_int options) 665{ 666 FILE *f; 667 char line[8192], oline[8192], ktype[128]; 668 u_long linenum = 0; 669 char *cp, *cp2; 670 u_int kbits; 671 int hashed; 672 int s, r = 0; 673 struct hostkey_foreach_line lineinfo; 674 size_t l; 675 676 memset(&lineinfo, 0, sizeof(lineinfo)); 677 if (host == NULL && (options & HKF_WANT_MATCH) != 0) 678 return SSH_ERR_INVALID_ARGUMENT; 679 if ((f = fopen(path, "r")) == NULL) 680 return SSH_ERR_SYSTEM_ERROR; 681 682 debug3("%s: reading file \"%s\"", __func__, path); 683 while (read_keyfile_line(f, path, line, sizeof(line), &linenum) == 0) { 684 line[strcspn(line, "\n")] = '\0'; 685 strlcpy(oline, line, sizeof(oline)); 686 687 sshkey_free(lineinfo.key); 688 memset(&lineinfo, 0, sizeof(lineinfo)); 689 lineinfo.path = path; 690 lineinfo.linenum = linenum; 691 lineinfo.line = oline; 692 lineinfo.marker = MRK_NONE; 693 lineinfo.status = HKF_STATUS_OK; 694 lineinfo.keytype = KEY_UNSPEC; 695 696 /* Skip any leading whitespace, comments and empty lines. */ 697 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 698 ; 699 if (!*cp || *cp == '#' || *cp == '\n') { 700 if ((options & HKF_WANT_MATCH) == 0) { 701 lineinfo.status = HKF_STATUS_COMMENT; 702 if ((r = callback(&lineinfo, ctx)) != 0) 703 break; 704 } 705 continue; 706 } 707 708 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) { 709 verbose("%s: invalid marker at %s:%lu", 710 __func__, path, linenum); 711 if ((options & HKF_WANT_MATCH) == 0) 712 goto bad; 713 continue; 714 } 715 716 /* Find the end of the host name portion. */ 717 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++) 718 ; 719 lineinfo.hosts = cp; 720 *cp2++ = '\0'; 721 722 /* Check if the host name matches. */ 723 if (host != NULL) { 724 if ((s = match_maybe_hashed(host, lineinfo.hosts, 725 &hashed)) == -1) { 726 debug2("%s: %s:%ld: bad host hash \"%.32s\"", 727 __func__, path, linenum, lineinfo.hosts); 728 goto bad; 729 } 730 if (s == 1) { 731 lineinfo.status = HKF_STATUS_MATCHED; 732 lineinfo.match |= HKF_MATCH_HOST | 733 (hashed ? HKF_MATCH_HOST_HASHED : 0); 734 } 735 /* Try matching IP address if supplied */ 736 if (ip != NULL) { 737 if ((s = match_maybe_hashed(ip, lineinfo.hosts, 738 &hashed)) == -1) { 739 debug2("%s: %s:%ld: bad ip hash " 740 "\"%.32s\"", __func__, path, 741 linenum, lineinfo.hosts); 742 goto bad; 743 } 744 if (s == 1) { 745 lineinfo.status = HKF_STATUS_MATCHED; 746 lineinfo.match |= HKF_MATCH_IP | 747 (hashed ? HKF_MATCH_IP_HASHED : 0); 748 } 749 } 750 /* 751 * Skip this line if host matching requested and 752 * neither host nor address matched. 753 */ 754 if ((options & HKF_WANT_MATCH) != 0 && 755 lineinfo.status != HKF_STATUS_MATCHED) 756 continue; 757 } 758 759 /* Got a match. Skip host name and any following whitespace */ 760 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 761 ; 762 if (*cp2 == '\0' || *cp2 == '#') { 763 debug2("%s:%ld: truncated before key type", 764 path, linenum); 765 goto bad; 766 } 767 lineinfo.rawkey = cp = cp2; 768 769 if ((options & HKF_WANT_PARSE_KEY) != 0) { 770 /* 771 * Extract the key from the line. This will skip 772 * any leading whitespace. Ignore badly formatted 773 * lines. 774 */ 775 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) { 776 error("%s: sshkey_new failed", __func__); 777 r = SSH_ERR_ALLOC_FAIL; 778 break; 779 } 780 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) { 781 goto bad; 782 } 783 lineinfo.keytype = lineinfo.key->type; 784 lineinfo.comment = cp; 785 } else { 786 /* Extract and parse key type */ 787 l = strcspn(lineinfo.rawkey, " \t"); 788 if (l <= 1 || l >= sizeof(ktype) || 789 lineinfo.rawkey[l] == '\0') 790 goto bad; 791 memcpy(ktype, lineinfo.rawkey, l); 792 ktype[l] = '\0'; 793 lineinfo.keytype = sshkey_type_from_name(ktype); 794 795 /* 796 * Assume legacy RSA1 if the first component is a short 797 * decimal number. 798 */ 799 if (lineinfo.keytype == KEY_UNSPEC && l < 8 && 800 strspn(ktype, "0123456789") == l) 801 goto bad; 802 803 /* 804 * Check that something other than whitespace follows 805 * the key type. This won't catch all corruption, but 806 * it does catch trivial truncation. 807 */ 808 cp2 += l; /* Skip past key type */ 809 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++) 810 ; 811 if (*cp2 == '\0' || *cp2 == '#') { 812 debug2("%s:%ld: truncated after key type", 813 path, linenum); 814 lineinfo.keytype = KEY_UNSPEC; 815 } 816 if (lineinfo.keytype == KEY_UNSPEC) { 817 bad: 818 sshkey_free(lineinfo.key); 819 lineinfo.key = NULL; 820 lineinfo.status = HKF_STATUS_INVALID; 821 if ((r = callback(&lineinfo, ctx)) != 0) 822 break; 823 continue; 824 } 825 } 826 if ((r = callback(&lineinfo, ctx)) != 0) 827 break; 828 } 829 sshkey_free(lineinfo.key); 830 fclose(f); 831 return r; 832} 833