1 /* $OpenBSD: hostfile.c,v 1.64 2015/02/16 22:08:57 djm 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 "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
extract_salt(const char * s,u_int l,u_char * salt,size_t salt_len)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 *
host_hash(const char * host,const char * name_from_hostfile,u_int src_len)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
hostfile_read_key(char ** cpp,u_int * bitsp,struct sshkey * ret)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
check_markers(char ** cpp)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 *
init_hostkeys(void)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
record_hostkey(struct hostkey_foreach_line * l,void * _ctx)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 error("%s:%ld: parse error in hostkeys file",
246 l->path, l->linenum);
247 return 0;
248 }
249
250 debug3("%s: found %skey type %s in file %s:%lu", __func__,
251 l->marker == MRK_NONE ? "" :
252 (l->marker == MRK_CA ? "ca " : "revoked "),
253 sshkey_type(l->key), l->path, l->linenum);
254 if ((tmp = reallocarray(hostkeys->entries,
255 hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL)
256 return SSH_ERR_ALLOC_FAIL;
257 hostkeys->entries = tmp;
258 hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host);
259 hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path);
260 hostkeys->entries[hostkeys->num_entries].line = l->linenum;
261 hostkeys->entries[hostkeys->num_entries].key = l->key;
262 l->key = NULL; /* steal it */
263 hostkeys->entries[hostkeys->num_entries].marker = l->marker;
264 hostkeys->num_entries++;
265 ctx->num_loaded++;
266
267 return 0;
268 }
269
270 void
load_hostkeys(struct hostkeys * hostkeys,const char * host,const char * path)271 load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path)
272 {
273 int r;
274 struct load_callback_ctx ctx;
275
276 ctx.host = host;
277 ctx.num_loaded = 0;
278 ctx.hostkeys = hostkeys;
279
280 if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL,
281 HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) {
282 if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT)
283 debug("%s: hostkeys_foreach failed for %s: %s",
284 __func__, path, ssh_err(r));
285 }
286 if (ctx.num_loaded != 0)
287 debug3("%s: loaded %lu keys from %s", __func__,
288 ctx.num_loaded, host);
289 }
290
291 void
free_hostkeys(struct hostkeys * hostkeys)292 free_hostkeys(struct hostkeys *hostkeys)
293 {
294 u_int i;
295
296 for (i = 0; i < hostkeys->num_entries; i++) {
297 free(hostkeys->entries[i].host);
298 free(hostkeys->entries[i].file);
299 sshkey_free(hostkeys->entries[i].key);
300 explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries));
301 }
302 free(hostkeys->entries);
303 explicit_bzero(hostkeys, sizeof(*hostkeys));
304 free(hostkeys);
305 }
306
307 static int
check_key_not_revoked(struct hostkeys * hostkeys,struct sshkey * k)308 check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k)
309 {
310 int is_cert = sshkey_is_cert(k);
311 u_int i;
312
313 for (i = 0; i < hostkeys->num_entries; i++) {
314 if (hostkeys->entries[i].marker != MRK_REVOKE)
315 continue;
316 if (sshkey_equal_public(k, hostkeys->entries[i].key))
317 return -1;
318 if (is_cert &&
319 sshkey_equal_public(k->cert->signature_key,
320 hostkeys->entries[i].key))
321 return -1;
322 }
323 return 0;
324 }
325
326 /*
327 * Match keys against a specified key, or look one up by key type.
328 *
329 * If looking for a keytype (key == NULL) and one is found then return
330 * HOST_FOUND, otherwise HOST_NEW.
331 *
332 * If looking for a key (key != NULL):
333 * 1. If the key is a cert and a matching CA is found, return HOST_OK
334 * 2. If the key is not a cert and a matching key is found, return HOST_OK
335 * 3. If no key matches but a key with a different type is found, then
336 * return HOST_CHANGED
337 * 4. If no matching keys are found, then return HOST_NEW.
338 *
339 * Finally, check any found key is not revoked.
340 */
341 static HostStatus
check_hostkeys_by_key_or_type(struct hostkeys * hostkeys,struct sshkey * k,int keytype,const struct hostkey_entry ** found)342 check_hostkeys_by_key_or_type(struct hostkeys *hostkeys,
343 struct sshkey *k, int keytype, const struct hostkey_entry **found)
344 {
345 u_int i;
346 HostStatus end_return = HOST_NEW;
347 int want_cert = sshkey_is_cert(k);
348 HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE;
349 int proto = (k ? k->type : keytype) == KEY_RSA1 ? 1 : 2;
350
351 if (found != NULL)
352 *found = NULL;
353
354 for (i = 0; i < hostkeys->num_entries; i++) {
355 if (proto == 1 && hostkeys->entries[i].key->type != KEY_RSA1)
356 continue;
357 if (proto == 2 && hostkeys->entries[i].key->type == KEY_RSA1)
358 continue;
359 if (hostkeys->entries[i].marker != want_marker)
360 continue;
361 if (k == NULL) {
362 if (hostkeys->entries[i].key->type != keytype)
363 continue;
364 end_return = HOST_FOUND;
365 if (found != NULL)
366 *found = hostkeys->entries + i;
367 k = hostkeys->entries[i].key;
368 break;
369 }
370 if (want_cert) {
371 if (sshkey_equal_public(k->cert->signature_key,
372 hostkeys->entries[i].key)) {
373 /* A matching CA exists */
374 end_return = HOST_OK;
375 if (found != NULL)
376 *found = hostkeys->entries + i;
377 break;
378 }
379 } else {
380 if (sshkey_equal(k, hostkeys->entries[i].key)) {
381 end_return = HOST_OK;
382 if (found != NULL)
383 *found = hostkeys->entries + i;
384 break;
385 }
386 /* A non-maching key exists */
387 end_return = HOST_CHANGED;
388 if (found != NULL)
389 *found = hostkeys->entries + i;
390 }
391 }
392 if (check_key_not_revoked(hostkeys, k) != 0) {
393 end_return = HOST_REVOKED;
394 if (found != NULL)
395 *found = NULL;
396 }
397 return end_return;
398 }
399
400 HostStatus
check_key_in_hostkeys(struct hostkeys * hostkeys,struct sshkey * key,const struct hostkey_entry ** found)401 check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key,
402 const struct hostkey_entry **found)
403 {
404 if (key == NULL)
405 fatal("no key to look up");
406 return check_hostkeys_by_key_or_type(hostkeys, key, 0, found);
407 }
408
409 int
lookup_key_in_hostkeys_by_type(struct hostkeys * hostkeys,int keytype,const struct hostkey_entry ** found)410 lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype,
411 const struct hostkey_entry **found)
412 {
413 return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype,
414 found) == HOST_FOUND);
415 }
416
417 static int
write_host_entry(FILE * f,const char * host,const char * ip,const struct sshkey * key,int store_hash)418 write_host_entry(FILE *f, const char *host, const char *ip,
419 const struct sshkey *key, int store_hash)
420 {
421 int r, success = 0;
422 char *hashed_host = NULL;
423
424 if (store_hash) {
425 if ((hashed_host = host_hash(host, NULL, 0)) == NULL) {
426 error("%s: host_hash failed", __func__);
427 return 0;
428 }
429 fprintf(f, "%s ", hashed_host);
430 } else if (ip != NULL)
431 fprintf(f, "%s,%s ", host, ip);
432 else
433 fprintf(f, "%s ", host);
434
435 if ((r = sshkey_write(key, f)) == 0)
436 success = 1;
437 else
438 error("%s: sshkey_write failed: %s", __func__, ssh_err(r));
439 fputc('\n', f);
440 return success;
441 }
442
443 /*
444 * Appends an entry to the host file. Returns false if the entry could not
445 * be appended.
446 */
447 int
add_host_to_hostfile(const char * filename,const char * host,const struct sshkey * key,int store_hash)448 add_host_to_hostfile(const char *filename, const char *host,
449 const struct sshkey *key, int store_hash)
450 {
451 FILE *f;
452 int success;
453
454 if (key == NULL)
455 return 1; /* XXX ? */
456 f = fopen(filename, "a");
457 if (!f)
458 return 0;
459 success = write_host_entry(f, host, NULL, key, store_hash);
460 fclose(f);
461 return success;
462 }
463
464 struct host_delete_ctx {
465 FILE *out;
466 int quiet;
467 const char *host;
468 int *skip_keys; /* XXX split for host/ip? might want to ensure both */
469 struct sshkey * const *keys;
470 size_t nkeys;
471 int modified;
472 };
473
474 static int
host_delete(struct hostkey_foreach_line * l,void * _ctx)475 host_delete(struct hostkey_foreach_line *l, void *_ctx)
476 {
477 struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx;
478 int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
479 size_t i;
480
481 if (l->status == HKF_STATUS_MATCHED) {
482 if (l->marker != MRK_NONE) {
483 /* Don't remove CA and revocation lines */
484 fprintf(ctx->out, "%s\n", l->line);
485 return 0;
486 }
487
488 /* XXX might need a knob for this later */
489 /* Don't remove RSA1 keys */
490 if (l->key->type == KEY_RSA1) {
491 fprintf(ctx->out, "%s\n", l->line);
492 return 0;
493 }
494
495 /*
496 * If this line contains one of the keys that we will be
497 * adding later, then don't change it and mark the key for
498 * skipping.
499 */
500 for (i = 0; i < ctx->nkeys; i++) {
501 if (sshkey_equal(ctx->keys[i], l->key)) {
502 ctx->skip_keys[i] = 1;
503 fprintf(ctx->out, "%s\n", l->line);
504 debug3("%s: %s key already at %s:%ld", __func__,
505 sshkey_type(l->key), l->path, l->linenum);
506 return 0;
507 }
508 }
509
510 /*
511 * Hostname matches and has no CA/revoke marker, delete it
512 * by *not* writing the line to ctx->out.
513 */
514 do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
515 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
516 l->path, l->linenum, sshkey_type(l->key), ctx->host);
517 ctx->modified = 1;
518 return 0;
519 }
520 /* Retain non-matching hosts and invalid lines when deleting */
521 if (l->status == HKF_STATUS_INVALID) {
522 do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry",
523 ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
524 l->path, l->linenum);
525 }
526 fprintf(ctx->out, "%s\n", l->line);
527 return 0;
528 }
529
530 int
hostfile_replace_entries(const char * filename,const char * host,const char * ip,struct sshkey ** keys,size_t nkeys,int store_hash,int quiet,int hash_alg)531 hostfile_replace_entries(const char *filename, const char *host, const char *ip,
532 struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg)
533 {
534 int r, fd, oerrno = 0;
535 int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
536 struct host_delete_ctx ctx;
537 char *fp, *temp = NULL, *back = NULL;
538 mode_t omask;
539 size_t i;
540
541 omask = umask(077);
542
543 memset(&ctx, 0, sizeof(ctx));
544 ctx.host = host;
545 ctx.quiet = quiet;
546 if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL)
547 return SSH_ERR_ALLOC_FAIL;
548 ctx.keys = keys;
549 ctx.nkeys = nkeys;
550 ctx.modified = 0;
551
552 /*
553 * Prepare temporary file for in-place deletion.
554 */
555 if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) < 0 ||
556 (r = asprintf(&back, "%s.old", filename)) < 0) {
557 r = SSH_ERR_ALLOC_FAIL;
558 goto fail;
559 }
560
561 if ((fd = mkstemp(temp)) == -1) {
562 oerrno = errno;
563 error("%s: mkstemp: %s", __func__, strerror(oerrno));
564 r = SSH_ERR_SYSTEM_ERROR;
565 goto fail;
566 }
567 if ((ctx.out = fdopen(fd, "w")) == NULL) {
568 oerrno = errno;
569 close(fd);
570 error("%s: fdopen: %s", __func__, strerror(oerrno));
571 r = SSH_ERR_SYSTEM_ERROR;
572 goto fail;
573 }
574
575 /* Remove all entries for the specified host from the file */
576 if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
577 HKF_WANT_PARSE_KEY)) != 0) {
578 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));
579 goto fail;
580 }
581
582 /* Add the requested keys */
583 for (i = 0; i < nkeys; i++) {
584 if (ctx.skip_keys[i])
585 continue;
586 if ((fp = sshkey_fingerprint(keys[i], hash_alg,
587 SSH_FP_DEFAULT)) == NULL) {
588 r = SSH_ERR_ALLOC_FAIL;
589 goto fail;
590 }
591 do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s",
592 quiet ? __func__ : "", quiet ? ": " : "", host, filename,
593 sshkey_ssh_name(keys[i]), fp);
594 free(fp);
595 if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) {
596 r = SSH_ERR_INTERNAL_ERROR;
597 goto fail;
598 }
599 ctx.modified = 1;
600 }
601 fclose(ctx.out);
602 ctx.out = NULL;
603
604 if (ctx.modified) {
605 /* Backup the original file and replace it with the temporary */
606 if (unlink(back) == -1 && errno != ENOENT) {
607 oerrno = errno;
608 error("%s: unlink %.100s: %s", __func__,
609 back, strerror(errno));
610 r = SSH_ERR_SYSTEM_ERROR;
611 goto fail;
612 }
613 if (link(filename, back) == -1) {
614 oerrno = errno;
615 error("%s: link %.100s to %.100s: %s", __func__,
616 filename, back, strerror(errno));
617 r = SSH_ERR_SYSTEM_ERROR;
618 goto fail;
619 }
620 if (rename(temp, filename) == -1) {
621 oerrno = errno;
622 error("%s: rename \"%s\" to \"%s\": %s", __func__,
623 temp, filename, strerror(errno));
624 r = SSH_ERR_SYSTEM_ERROR;
625 goto fail;
626 }
627 } else {
628 /* No changes made; just delete the temporary file */
629 if (unlink(temp) != 0)
630 error("%s: unlink \"%s\": %s", __func__,
631 temp, strerror(errno));
632 }
633
634 /* success */
635 r = 0;
636 fail:
637 if (temp != NULL && r != 0)
638 unlink(temp);
639 free(temp);
640 free(back);
641 if (ctx.out != NULL)
642 fclose(ctx.out);
643 free(ctx.skip_keys);
644 umask(omask);
645 if (r == SSH_ERR_SYSTEM_ERROR)
646 errno = oerrno;
647 return r;
648 }
649
650 static int
match_maybe_hashed(const char * host,const char * names,int * was_hashed)651 match_maybe_hashed(const char *host, const char *names, int *was_hashed)
652 {
653 int hashed = *names == HASH_DELIM;
654 const char *hashed_host;
655 size_t nlen = strlen(names);
656
657 if (was_hashed != NULL)
658 *was_hashed = hashed;
659 if (hashed) {
660 if ((hashed_host = host_hash(host, names, nlen)) == NULL)
661 return -1;
662 return nlen == strlen(hashed_host) &&
663 strncmp(hashed_host, names, nlen) == 0;
664 }
665 return match_hostname(host, names, nlen) == 1;
666 }
667
668 int
hostkeys_foreach(const char * path,hostkeys_foreach_fn * callback,void * ctx,const char * host,const char * ip,u_int options)669 hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
670 const char *host, const char *ip, u_int options)
671 {
672 FILE *f;
673 char line[8192], oline[8192], ktype[128];
674 u_long linenum = 0;
675 char *cp, *cp2;
676 u_int kbits;
677 int hashed;
678 int s, r = 0;
679 struct hostkey_foreach_line lineinfo;
680 size_t l;
681
682 memset(&lineinfo, 0, sizeof(lineinfo));
683 if (host == NULL && (options & HKF_WANT_MATCH) != 0)
684 return SSH_ERR_INVALID_ARGUMENT;
685 if ((f = fopen(path, "r")) == NULL)
686 return SSH_ERR_SYSTEM_ERROR;
687
688 debug3("%s: reading file \"%s\"", __func__, path);
689 while (read_keyfile_line(f, path, line, sizeof(line), &linenum) == 0) {
690 line[strcspn(line, "\n")] = '\0';
691 strlcpy(oline, line, sizeof(oline));
692
693 sshkey_free(lineinfo.key);
694 memset(&lineinfo, 0, sizeof(lineinfo));
695 lineinfo.path = path;
696 lineinfo.linenum = linenum;
697 lineinfo.line = oline;
698 lineinfo.marker = MRK_NONE;
699 lineinfo.status = HKF_STATUS_OK;
700 lineinfo.keytype = KEY_UNSPEC;
701
702 /* Skip any leading whitespace, comments and empty lines. */
703 for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
704 ;
705 if (!*cp || *cp == '#' || *cp == '\n') {
706 if ((options & HKF_WANT_MATCH) == 0) {
707 lineinfo.status = HKF_STATUS_COMMENT;
708 if ((r = callback(&lineinfo, ctx)) != 0)
709 break;
710 }
711 continue;
712 }
713
714 if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
715 verbose("%s: invalid marker at %s:%lu",
716 __func__, path, linenum);
717 if ((options & HKF_WANT_MATCH) == 0)
718 goto bad;
719 continue;
720 }
721
722 /* Find the end of the host name portion. */
723 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
724 ;
725 lineinfo.hosts = cp;
726 *cp2++ = '\0';
727
728 /* Check if the host name matches. */
729 if (host != NULL) {
730 if ((s = match_maybe_hashed(host, lineinfo.hosts,
731 &hashed)) == -1) {
732 debug2("%s: %s:%ld: bad host hash \"%.32s\"",
733 __func__, path, linenum, lineinfo.hosts);
734 goto bad;
735 }
736 if (s == 1) {
737 lineinfo.status = HKF_STATUS_MATCHED;
738 lineinfo.match |= HKF_MATCH_HOST |
739 (hashed ? HKF_MATCH_HOST_HASHED : 0);
740 }
741 /* Try matching IP address if supplied */
742 if (ip != NULL) {
743 if ((s = match_maybe_hashed(ip, lineinfo.hosts,
744 &hashed)) == -1) {
745 debug2("%s: %s:%ld: bad ip hash "
746 "\"%.32s\"", __func__, path,
747 linenum, lineinfo.hosts);
748 goto bad;
749 }
750 if (s == 1) {
751 lineinfo.status = HKF_STATUS_MATCHED;
752 lineinfo.match |= HKF_MATCH_IP |
753 (hashed ? HKF_MATCH_IP_HASHED : 0);
754 }
755 }
756 /*
757 * Skip this line if host matching requested and
758 * neither host nor address matched.
759 */
760 if ((options & HKF_WANT_MATCH) != 0 &&
761 lineinfo.status != HKF_STATUS_MATCHED)
762 continue;
763 }
764
765 /* Got a match. Skip host name and any following whitespace */
766 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
767 ;
768 if (*cp2 == '\0' || *cp2 == '#') {
769 debug2("%s:%ld: truncated before key type",
770 path, linenum);
771 goto bad;
772 }
773 lineinfo.rawkey = cp = cp2;
774
775 if ((options & HKF_WANT_PARSE_KEY) != 0) {
776 /*
777 * Extract the key from the line. This will skip
778 * any leading whitespace. Ignore badly formatted
779 * lines.
780 */
781 if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
782 error("%s: sshkey_new failed", __func__);
783 r = SSH_ERR_ALLOC_FAIL;
784 break;
785 }
786 if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
787 #ifdef WITH_SSH1
788 sshkey_free(lineinfo.key);
789 lineinfo.key = sshkey_new(KEY_RSA1);
790 if (lineinfo.key == NULL) {
791 error("%s: sshkey_new fail", __func__);
792 r = SSH_ERR_ALLOC_FAIL;
793 break;
794 }
795 if (!hostfile_read_key(&cp, &kbits,
796 lineinfo.key))
797 goto bad;
798 #else
799 goto bad;
800 #endif
801 }
802 lineinfo.keytype = lineinfo.key->type;
803 lineinfo.comment = cp;
804 } else {
805 /* Extract and parse key type */
806 l = strcspn(lineinfo.rawkey, " \t");
807 if (l <= 1 || l >= sizeof(ktype) ||
808 lineinfo.rawkey[l] == '\0')
809 goto bad;
810 memcpy(ktype, lineinfo.rawkey, l);
811 ktype[l] = '\0';
812 lineinfo.keytype = sshkey_type_from_name(ktype);
813 #ifdef WITH_SSH1
814 /*
815 * Assume RSA1 if the first component is a short
816 * decimal number.
817 */
818 if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
819 strspn(ktype, "0123456789") == l)
820 lineinfo.keytype = KEY_RSA1;
821 #endif
822 /*
823 * Check that something other than whitespace follows
824 * the key type. This won't catch all corruption, but
825 * it does catch trivial truncation.
826 */
827 cp2 += l; /* Skip past key type */
828 for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
829 ;
830 if (*cp2 == '\0' || *cp2 == '#') {
831 debug2("%s:%ld: truncated after key type",
832 path, linenum);
833 lineinfo.keytype = KEY_UNSPEC;
834 }
835 if (lineinfo.keytype == KEY_UNSPEC) {
836 bad:
837 sshkey_free(lineinfo.key);
838 lineinfo.key = NULL;
839 lineinfo.status = HKF_STATUS_INVALID;
840 if ((r = callback(&lineinfo, ctx)) != 0)
841 break;
842 continue;
843 }
844 }
845 if ((r = callback(&lineinfo, ctx)) != 0)
846 break;
847 }
848 sshkey_free(lineinfo.key);
849 fclose(f);
850 return r;
851 }
852