Annotation of src/usr.bin/ssh/hostfile.c, Revision 1.86
1.86 ! djm 1: /* $OpenBSD: hostfile.c,v 1.85 2020/10/11 22:13:37 djm Exp $ */
1.1 deraadt 2: /*
1.8 deraadt 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.
1.16 markus 7: *
1.20 deraadt 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: *
1.28 markus 15: * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved.
1.20 deraadt 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.
1.8 deraadt 37: */
1.1 deraadt 38:
1.41 stevesk 39: #include <sys/types.h>
1.62 djm 40: #include <sys/stat.h>
1.41 stevesk 41:
42: #include <netinet/in.h>
1.33 djm 43:
1.60 djm 44: #include <errno.h>
1.33 djm 45: #include <resolv.h>
1.44 stevesk 46: #include <stdio.h>
1.43 stevesk 47: #include <stdlib.h>
1.42 stevesk 48: #include <string.h>
1.57 djm 49: #include <stdarg.h>
1.62 djm 50: #include <unistd.h>
1.1 deraadt 51:
1.45 deraadt 52: #include "xmalloc.h"
1.14 markus 53: #include "match.h"
1.59 djm 54: #include "sshkey.h"
1.14 markus 55: #include "hostfile.h"
1.24 markus 56: #include "log.h"
1.49 djm 57: #include "misc.h"
1.81 dtucker 58: #include "pathnames.h"
1.59 djm 59: #include "ssherr.h"
1.53 djm 60: #include "digest.h"
1.54 markus 61: #include "hmac.h"
1.49 djm 62:
63: struct hostkeys {
64: struct hostkey_entry *entries;
65: u_int num_entries;
66: };
1.33 djm 67:
1.60 djm 68: /* XXX hmac is too easy to dictionary attack; use bcrypt? */
69:
1.33 djm 70: static int
1.52 djm 71: extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len)
1.33 djm 72: {
73: char *p, *b64salt;
74: u_int b64len;
75: int ret;
76:
77: if (l < sizeof(HASH_MAGIC) - 1) {
78: debug2("extract_salt: string too short");
79: return (-1);
80: }
81: if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) {
82: debug2("extract_salt: invalid magic identifier");
83: return (-1);
84: }
85: s += sizeof(HASH_MAGIC) - 1;
86: l -= sizeof(HASH_MAGIC) - 1;
87: if ((p = memchr(s, HASH_DELIM, l)) == NULL) {
88: debug2("extract_salt: missing salt termination character");
89: return (-1);
90: }
91:
92: b64len = p - s;
93: /* Sanity check */
94: if (b64len == 0 || b64len > 1024) {
95: debug2("extract_salt: bad encoded salt length %u", b64len);
96: return (-1);
97: }
98: b64salt = xmalloc(1 + b64len);
99: memcpy(b64salt, s, b64len);
100: b64salt[b64len] = '\0';
101:
102: ret = __b64_pton(b64salt, salt, salt_len);
1.51 djm 103: free(b64salt);
1.33 djm 104: if (ret == -1) {
105: debug2("extract_salt: salt decode error");
106: return (-1);
107: }
1.54 markus 108: if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) {
109: debug2("extract_salt: expected salt len %zd, got %d",
110: ssh_hmac_bytes(SSH_DIGEST_SHA1), ret);
1.33 djm 111: return (-1);
112: }
1.34 deraadt 113:
1.33 djm 114: return (0);
115: }
116:
117: char *
118: host_hash(const char *host, const char *name_from_hostfile, u_int src_len)
119: {
1.54 markus 120: struct ssh_hmac_ctx *ctx;
1.52 djm 121: u_char salt[256], result[256];
122: char uu_salt[512], uu_result[512];
1.33 djm 123: static char encoded[1024];
1.67 tedu 124: u_int len;
1.33 djm 125:
1.54 markus 126: len = ssh_digest_bytes(SSH_DIGEST_SHA1);
1.33 djm 127:
128: if (name_from_hostfile == NULL) {
129: /* Create new salt */
1.67 tedu 130: arc4random_buf(salt, len);
1.33 djm 131: } else {
132: /* Extract salt from known host entry */
133: if (extract_salt(name_from_hostfile, src_len, salt,
134: sizeof(salt)) == -1)
135: return (NULL);
136: }
137:
1.54 markus 138: if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL ||
139: ssh_hmac_init(ctx, salt, len) < 0 ||
140: ssh_hmac_update(ctx, host, strlen(host)) < 0 ||
141: ssh_hmac_final(ctx, result, sizeof(result)))
1.86 ! djm 142: fatal_f("ssh_hmac failed");
1.54 markus 143: ssh_hmac_free(ctx);
1.33 djm 144:
1.34 deraadt 145: if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 ||
1.33 djm 146: __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1)
1.86 ! djm 147: fatal_f("__b64_ntop failed");
1.33 djm 148:
149: snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt,
150: HASH_DELIM, uu_result);
151:
152: return (encoded);
153: }
1.1 deraadt 154:
1.9 markus 155: /*
1.14 markus 156: * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the
157: * pointer over the key. Skips any whitespace at the beginning and at end.
1.9 markus 158: */
1.1 deraadt 159:
1.29 jakob 160: int
1.59 djm 161: hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret)
1.1 deraadt 162: {
1.7 markus 163: char *cp;
164:
165: /* Skip leading whitespace. */
1.9 markus 166: for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
167: ;
1.1 deraadt 168:
1.76 dtucker 169: if (sshkey_read(ret, &cp) != 0)
1.7 markus 170: return 0;
171:
172: /* Skip trailing whitespace. */
1.9 markus 173: for (; *cp == ' ' || *cp == '\t'; cp++)
174: ;
1.7 markus 175:
176: /* Return results. */
177: *cpp = cp;
1.59 djm 178: if (bitsp != NULL)
179: *bitsp = sshkey_size(ret);
1.7 markus 180: return 1;
1.14 markus 181: }
1.1 deraadt 182:
1.49 djm 183: static HostkeyMarker
1.48 djm 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:
1.49 djm 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: }
1.1 deraadt 226:
1.61 djm 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)
1.1 deraadt 235: {
1.61 djm 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) {
1.65 djm 241: /* XXX make this verbose() in the future */
242: debug("%s:%ld: parse error in hostkeys file",
1.61 djm 243: l->path, l->linenum);
244: return 0;
245: }
1.7 markus 246:
1.86 ! djm 247: debug3_f("found %skey type %s in file %s:%lu",
1.61 djm 248: l->marker == MRK_NONE ? "" :
249: (l->marker == MRK_CA ? "ca " : "revoked "),
250: sshkey_type(l->key), l->path, l->linenum);
1.71 deraadt 251: if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries,
1.61 djm 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++;
1.7 markus 263:
1.61 djm 264: return 0;
265: }
1.47 djm 266:
1.61 djm 267: void
268: load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path)
269: {
270: int r;
271: struct load_callback_ctx ctx;
1.7 markus 272:
1.61 djm 273: ctx.host = host;
274: ctx.num_loaded = 0;
275: ctx.hostkeys = hostkeys;
276:
1.64 djm 277: if ((r = hostkeys_foreach(path, record_hostkey, &ctx, host, NULL,
278: HKF_WANT_MATCH|HKF_WANT_PARSE_KEY)) != 0) {
1.61 djm 279: if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT)
1.86 ! djm 280: debug_fr(r, "hostkeys_foreach failed for %s", path);
1.61 djm 281: }
282: if (ctx.num_loaded != 0)
1.86 ! djm 283: debug3_f("loaded %lu keys from %s", ctx.num_loaded, host);
1.58 djm 284: }
1.49 djm 285:
286: void
287: free_hostkeys(struct hostkeys *hostkeys)
288: {
289: u_int i;
290:
291: for (i = 0; i < hostkeys->num_entries; i++) {
1.51 djm 292: free(hostkeys->entries[i].host);
293: free(hostkeys->entries[i].file);
1.59 djm 294: sshkey_free(hostkeys->entries[i].key);
1.55 tedu 295: explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries));
1.49 djm 296: }
1.51 djm 297: free(hostkeys->entries);
1.78 jsg 298: freezero(hostkeys, sizeof(*hostkeys));
1.49 djm 299: }
300:
301: static int
1.59 djm 302: check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k)
1.49 djm 303: {
1.59 djm 304: int is_cert = sshkey_is_cert(k);
1.49 djm 305: u_int i;
1.7 markus 306:
1.49 djm 307: for (i = 0; i < hostkeys->num_entries; i++) {
308: if (hostkeys->entries[i].marker != MRK_REVOKE)
1.30 markus 309: continue;
1.59 djm 310: if (sshkey_equal_public(k, hostkeys->entries[i].key))
1.49 djm 311: return -1;
1.79 markus 312: if (is_cert && k != NULL &&
1.59 djm 313: sshkey_equal_public(k->cert->signature_key,
1.49 djm 314: hostkeys->entries[i].key))
315: return -1;
316: }
317: return 0;
318: }
319:
320: /*
321: * Match keys against a specified key, or look one up by key type.
322: *
323: * If looking for a keytype (key == NULL) and one is found then return
324: * HOST_FOUND, otherwise HOST_NEW.
325: *
326: * If looking for a key (key != NULL):
327: * 1. If the key is a cert and a matching CA is found, return HOST_OK
328: * 2. If the key is not a cert and a matching key is found, return HOST_OK
329: * 3. If no key matches but a key with a different type is found, then
330: * return HOST_CHANGED
331: * 4. If no matching keys are found, then return HOST_NEW.
332: *
333: * Finally, check any found key is not revoked.
334: */
335: static HostStatus
336: check_hostkeys_by_key_or_type(struct hostkeys *hostkeys,
1.83 djm 337: struct sshkey *k, int keytype, int nid, const struct hostkey_entry **found)
1.49 djm 338: {
339: u_int i;
340: HostStatus end_return = HOST_NEW;
1.59 djm 341: int want_cert = sshkey_is_cert(k);
1.49 djm 342: HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE;
343:
344: if (found != NULL)
345: *found = NULL;
1.30 markus 346:
1.49 djm 347: for (i = 0; i < hostkeys->num_entries; i++) {
348: if (hostkeys->entries[i].marker != want_marker)
349: continue;
350: if (k == NULL) {
351: if (hostkeys->entries[i].key->type != keytype)
352: continue;
1.83 djm 353: if (nid != -1 &&
354: sshkey_type_plain(keytype) == KEY_ECDSA &&
355: hostkeys->entries[i].key->ecdsa_nid != nid)
356: continue;
1.49 djm 357: end_return = HOST_FOUND;
358: if (found != NULL)
359: *found = hostkeys->entries + i;
360: k = hostkeys->entries[i].key;
361: break;
362: }
363: if (want_cert) {
1.59 djm 364: if (sshkey_equal_public(k->cert->signature_key,
1.49 djm 365: hostkeys->entries[i].key)) {
366: /* A matching CA exists */
367: end_return = HOST_OK;
368: if (found != NULL)
369: *found = hostkeys->entries + i;
370: break;
1.48 djm 371: }
1.49 djm 372: } else {
1.59 djm 373: if (sshkey_equal(k, hostkeys->entries[i].key)) {
1.49 djm 374: end_return = HOST_OK;
375: if (found != NULL)
376: *found = hostkeys->entries + i;
377: break;
1.48 djm 378: }
1.49 djm 379: /* A non-maching key exists */
380: end_return = HOST_CHANGED;
381: if (found != NULL)
382: *found = hostkeys->entries + i;
1.48 djm 383: }
1.1 deraadt 384: }
1.49 djm 385: if (check_key_not_revoked(hostkeys, k) != 0) {
386: end_return = HOST_REVOKED;
387: if (found != NULL)
388: *found = NULL;
389: }
1.7 markus 390: return end_return;
1.30 markus 391: }
1.58 djm 392:
1.30 markus 393: HostStatus
1.59 djm 394: check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key,
1.49 djm 395: const struct hostkey_entry **found)
1.30 markus 396: {
397: if (key == NULL)
398: fatal("no key to look up");
1.83 djm 399: return check_hostkeys_by_key_or_type(hostkeys, key, 0, -1, found);
1.30 markus 400: }
401:
402: int
1.83 djm 403: lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, int nid,
1.49 djm 404: const struct hostkey_entry **found)
1.30 markus 405: {
1.83 djm 406: return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, nid,
1.49 djm 407: found) == HOST_FOUND);
1.80 djm 408: }
409:
410: int
411: lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker)
412: {
413: u_int i;
414:
415: for (i = 0; i < hostkeys->num_entries; i++) {
416: if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker)
417: return 1;
418: }
419: return 0;
1.1 deraadt 420: }
421:
1.62 djm 422: static int
1.64 djm 423: write_host_entry(FILE *f, const char *host, const char *ip,
1.62 djm 424: const struct sshkey *key, int store_hash)
425: {
426: int r, success = 0;
1.68 djm 427: char *hashed_host = NULL, *lhost;
428:
429: lhost = xstrdup(host);
430: lowercase(lhost);
1.62 djm 431:
432: if (store_hash) {
1.68 djm 433: if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) {
1.86 ! djm 434: error_f("host_hash failed");
1.68 djm 435: free(lhost);
1.62 djm 436: return 0;
437: }
1.64 djm 438: fprintf(f, "%s ", hashed_host);
439: } else if (ip != NULL)
1.68 djm 440: fprintf(f, "%s,%s ", lhost, ip);
441: else {
442: fprintf(f, "%s ", lhost);
443: }
444: free(lhost);
1.62 djm 445: if ((r = sshkey_write(key, f)) == 0)
446: success = 1;
447: else
1.86 ! djm 448: error_fr(r, "sshkey_write");
1.62 djm 449: fputc('\n', f);
1.84 djm 450: /* If hashing is enabled, the IP address needs to go on its own line */
451: if (success && store_hash && ip != NULL)
452: success = write_host_entry(f, ip, NULL, key, 1);
1.62 djm 453: return success;
454: }
455:
1.9 markus 456: /*
1.81 dtucker 457: * Create user ~/.ssh directory if it doesn't exist and we want to write to it.
458: * If notify is set, a message will be emitted if the directory is created.
459: */
460: void
461: hostfile_create_user_ssh_dir(const char *filename, int notify)
462: {
463: char *dotsshdir = NULL, *p;
464: size_t len;
465: struct stat st;
466:
467: if ((p = strrchr(filename, '/')) == NULL)
468: return;
469: len = p - filename;
470: dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid());
1.82 djm 471: if (strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0)
472: goto out; /* not ~/.ssh prefixed */
473: if (stat(dotsshdir, &st) == 0)
474: goto out; /* dir already exists */
1.81 dtucker 475: else if (errno != ENOENT)
476: error("Could not stat %s: %s", dotsshdir, strerror(errno));
1.82 djm 477: else {
478: if (mkdir(dotsshdir, 0700) == -1)
479: error("Could not create directory '%.200s' (%s).",
480: dotsshdir, strerror(errno));
481: else if (notify)
482: logit("Created directory '%s'.", dotsshdir);
483: }
484: out:
1.81 dtucker 485: free(dotsshdir);
486: }
1.82 djm 487:
1.81 dtucker 488:
489: /*
1.9 markus 490: * Appends an entry to the host file. Returns false if the entry could not
491: * be appended.
492: */
1.2 provos 493: int
1.59 djm 494: add_host_to_hostfile(const char *filename, const char *host,
495: const struct sshkey *key, int store_hash)
1.1 deraadt 496: {
1.7 markus 497: FILE *f;
1.62 djm 498: int success;
1.33 djm 499:
1.14 markus 500: if (key == NULL)
1.17 markus 501: return 1; /* XXX ? */
1.81 dtucker 502: hostfile_create_user_ssh_dir(filename, 0);
1.7 markus 503: f = fopen(filename, "a");
504: if (!f)
505: return 0;
1.64 djm 506: success = write_host_entry(f, host, NULL, key, store_hash);
1.62 djm 507: fclose(f);
508: return success;
509: }
510:
511: struct host_delete_ctx {
512: FILE *out;
513: int quiet;
1.85 djm 514: const char *host, *ip;
515: u_int *match_keys; /* mask of HKF_MATCH_* for this key */
1.62 djm 516: struct sshkey * const *keys;
517: size_t nkeys;
1.64 djm 518: int modified;
1.62 djm 519: };
520:
521: static int
522: host_delete(struct hostkey_foreach_line *l, void *_ctx)
523: {
524: struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx;
1.64 djm 525: int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 526: size_t i;
527:
1.85 djm 528: /* Don't remove CA and revocation lines */
529: if (l->status == HKF_STATUS_MATCHED && l->marker == MRK_NONE) {
1.62 djm 530: /*
531: * If this line contains one of the keys that we will be
532: * adding later, then don't change it and mark the key for
533: * skipping.
534: */
535: for (i = 0; i < ctx->nkeys; i++) {
1.85 djm 536: if (!sshkey_equal(ctx->keys[i], l->key))
537: continue;
538: ctx->match_keys[i] |= l->match;
539: fprintf(ctx->out, "%s\n", l->line);
1.86 ! djm 540: debug3_f("%s key already at %s:%ld",
1.85 djm 541: sshkey_type(l->key), l->path, l->linenum);
542: return 0;
1.62 djm 543: }
544:
545: /*
546: * Hostname matches and has no CA/revoke marker, delete it
547: * by *not* writing the line to ctx->out.
548: */
1.64 djm 549: do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
1.62 djm 550: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
1.64 djm 551: l->path, l->linenum, sshkey_type(l->key), ctx->host);
552: ctx->modified = 1;
1.62 djm 553: return 0;
554: }
555: /* Retain non-matching hosts and invalid lines when deleting */
556: if (l->status == HKF_STATUS_INVALID) {
557: do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry",
558: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
559: l->path, l->linenum);
560: }
561: fprintf(ctx->out, "%s\n", l->line);
562: return 0;
563: }
564:
565: int
1.64 djm 566: hostfile_replace_entries(const char *filename, const char *host, const char *ip,
567: struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg)
1.62 djm 568: {
569: int r, fd, oerrno = 0;
1.64 djm 570: int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 571: struct host_delete_ctx ctx;
1.64 djm 572: char *fp, *temp = NULL, *back = NULL;
1.85 djm 573: const char *what;
1.62 djm 574: mode_t omask;
575: size_t i;
1.85 djm 576: u_int want;
1.62 djm 577:
1.63 djm 578: omask = umask(077);
579:
1.62 djm 580: memset(&ctx, 0, sizeof(ctx));
581: ctx.host = host;
1.85 djm 582: ctx.ip = ip;
1.62 djm 583: ctx.quiet = quiet;
1.85 djm 584:
585: if ((ctx.match_keys = calloc(nkeys, sizeof(*ctx.match_keys))) == NULL)
1.62 djm 586: return SSH_ERR_ALLOC_FAIL;
587: ctx.keys = keys;
588: ctx.nkeys = nkeys;
1.64 djm 589: ctx.modified = 0;
1.62 djm 590:
591: /*
592: * Prepare temporary file for in-place deletion.
593: */
1.75 deraadt 594: if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 ||
1.74 deraadt 595: (r = asprintf(&back, "%s.old", filename)) == -1) {
1.62 djm 596: r = SSH_ERR_ALLOC_FAIL;
597: goto fail;
598: }
599:
600: if ((fd = mkstemp(temp)) == -1) {
601: oerrno = errno;
1.86 ! djm 602: error_f("mkstemp: %s", strerror(oerrno));
1.62 djm 603: r = SSH_ERR_SYSTEM_ERROR;
604: goto fail;
605: }
606: if ((ctx.out = fdopen(fd, "w")) == NULL) {
607: oerrno = errno;
608: close(fd);
1.86 ! djm 609: error_f("fdopen: %s", strerror(oerrno));
1.62 djm 610: r = SSH_ERR_SYSTEM_ERROR;
611: goto fail;
612: }
613:
1.85 djm 614: /* Remove stale/mismatching entries for the specified host */
1.64 djm 615: if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
1.62 djm 616: HKF_WANT_PARSE_KEY)) != 0) {
1.77 djm 617: oerrno = errno;
1.86 ! djm 618: error_fr(r, "hostkeys_foreach");
1.62 djm 619: goto fail;
620: }
621:
1.85 djm 622: /* Re-add the requested keys */
623: want = HKF_MATCH_HOST | (ip == NULL ? 0 : HKF_MATCH_IP);
1.62 djm 624: for (i = 0; i < nkeys; i++) {
1.85 djm 625: if ((want & ctx.match_keys[i]) == want)
1.62 djm 626: continue;
1.64 djm 627: if ((fp = sshkey_fingerprint(keys[i], hash_alg,
628: SSH_FP_DEFAULT)) == NULL) {
629: r = SSH_ERR_ALLOC_FAIL;
630: goto fail;
631: }
1.85 djm 632: /* write host/ip */
633: what = "";
634: if (ctx.match_keys[i] == 0) {
635: what = "Adding new key";
636: if (!write_host_entry(ctx.out, host, ip,
637: keys[i], store_hash)) {
638: r = SSH_ERR_INTERNAL_ERROR;
639: goto fail;
640: }
641: } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_HOST) {
642: what = "Fixing match (hostname)";
643: if (!write_host_entry(ctx.out, host, NULL,
644: keys[i], store_hash)) {
645: r = SSH_ERR_INTERNAL_ERROR;
646: goto fail;
647: }
648: } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_IP) {
649: what = "Fixing match (address)";
650: if (!write_host_entry(ctx.out, ip, NULL,
651: keys[i], store_hash)) {
652: r = SSH_ERR_INTERNAL_ERROR;
653: goto fail;
654: }
655: }
656: do_log2(loglevel, "%s%s%s for %s%s%s to %s: %s %s",
657: quiet ? __func__ : "", quiet ? ": " : "", what,
658: host, ip == NULL ? "" : ",", ip == NULL ? "" : ip, filename,
1.64 djm 659: sshkey_ssh_name(keys[i]), fp);
660: free(fp);
661: ctx.modified = 1;
1.33 djm 662: }
1.62 djm 663: fclose(ctx.out);
664: ctx.out = NULL;
1.33 djm 665:
1.64 djm 666: if (ctx.modified) {
667: /* Backup the original file and replace it with the temporary */
668: if (unlink(back) == -1 && errno != ENOENT) {
669: oerrno = errno;
1.86 ! djm 670: error_f("unlink %.100s: %s", back, strerror(errno));
1.64 djm 671: r = SSH_ERR_SYSTEM_ERROR;
672: goto fail;
673: }
674: if (link(filename, back) == -1) {
675: oerrno = errno;
1.86 ! djm 676: error_f("link %.100s to %.100s: %s", filename,
! 677: back, strerror(errno));
1.64 djm 678: r = SSH_ERR_SYSTEM_ERROR;
679: goto fail;
680: }
681: if (rename(temp, filename) == -1) {
682: oerrno = errno;
1.86 ! djm 683: error_f("rename \"%s\" to \"%s\": %s", temp,
! 684: filename, strerror(errno));
1.64 djm 685: r = SSH_ERR_SYSTEM_ERROR;
686: goto fail;
687: }
688: } else {
689: /* No changes made; just delete the temporary file */
690: if (unlink(temp) != 0)
1.86 ! djm 691: error_f("unlink \"%s\": %s", temp, strerror(errno));
1.62 djm 692: }
1.64 djm 693:
1.62 djm 694: /* success */
695: r = 0;
696: fail:
697: if (temp != NULL && r != 0)
698: unlink(temp);
699: free(temp);
700: free(back);
701: if (ctx.out != NULL)
702: fclose(ctx.out);
1.85 djm 703: free(ctx.match_keys);
1.63 djm 704: umask(omask);
1.62 djm 705: if (r == SSH_ERR_SYSTEM_ERROR)
706: errno = oerrno;
707: return r;
1.60 djm 708: }
709:
710: static int
711: match_maybe_hashed(const char *host, const char *names, int *was_hashed)
712: {
713: int hashed = *names == HASH_DELIM;
714: const char *hashed_host;
715: size_t nlen = strlen(names);
716:
717: if (was_hashed != NULL)
718: *was_hashed = hashed;
719: if (hashed) {
720: if ((hashed_host = host_hash(host, names, nlen)) == NULL)
721: return -1;
722: return nlen == strlen(hashed_host) &&
723: strncmp(hashed_host, names, nlen) == 0;
724: }
1.66 djm 725: return match_hostname(host, names) == 1;
1.60 djm 726: }
727:
728: int
729: hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
1.64 djm 730: const char *host, const char *ip, u_int options)
1.60 djm 731: {
732: FILE *f;
1.72 markus 733: char *line = NULL, ktype[128];
1.60 djm 734: u_long linenum = 0;
735: char *cp, *cp2;
736: u_int kbits;
1.64 djm 737: int hashed;
1.60 djm 738: int s, r = 0;
739: struct hostkey_foreach_line lineinfo;
1.72 markus 740: size_t linesize = 0, l;
1.60 djm 741:
742: memset(&lineinfo, 0, sizeof(lineinfo));
1.64 djm 743: if (host == NULL && (options & HKF_WANT_MATCH) != 0)
1.60 djm 744: return SSH_ERR_INVALID_ARGUMENT;
745: if ((f = fopen(path, "r")) == NULL)
746: return SSH_ERR_SYSTEM_ERROR;
747:
1.86 ! djm 748: debug3_f("reading file \"%s\"", path);
1.72 markus 749: while (getline(&line, &linesize, f) != -1) {
750: linenum++;
1.60 djm 751: line[strcspn(line, "\n")] = '\0';
752:
1.73 djm 753: free(lineinfo.line);
1.60 djm 754: sshkey_free(lineinfo.key);
755: memset(&lineinfo, 0, sizeof(lineinfo));
756: lineinfo.path = path;
757: lineinfo.linenum = linenum;
1.72 markus 758: lineinfo.line = xstrdup(line);
1.64 djm 759: lineinfo.marker = MRK_NONE;
1.60 djm 760: lineinfo.status = HKF_STATUS_OK;
1.64 djm 761: lineinfo.keytype = KEY_UNSPEC;
1.60 djm 762:
763: /* Skip any leading whitespace, comments and empty lines. */
764: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
765: ;
766: if (!*cp || *cp == '#' || *cp == '\n') {
1.64 djm 767: if ((options & HKF_WANT_MATCH) == 0) {
1.60 djm 768: lineinfo.status = HKF_STATUS_COMMENT;
769: if ((r = callback(&lineinfo, ctx)) != 0)
770: break;
771: }
772: continue;
773: }
774:
775: if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
1.86 ! djm 776: verbose_f("invalid marker at %s:%lu", path, linenum);
1.64 djm 777: if ((options & HKF_WANT_MATCH) == 0)
1.60 djm 778: goto bad;
779: continue;
780: }
781:
782: /* Find the end of the host name portion. */
783: for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
784: ;
785: lineinfo.hosts = cp;
786: *cp2++ = '\0';
787:
788: /* Check if the host name matches. */
789: if (host != NULL) {
1.64 djm 790: if ((s = match_maybe_hashed(host, lineinfo.hosts,
791: &hashed)) == -1) {
1.86 ! djm 792: debug2_f("%s:%ld: bad host hash \"%.32s\"",
! 793: path, linenum, lineinfo.hosts);
1.60 djm 794: goto bad;
795: }
1.64 djm 796: if (s == 1) {
797: lineinfo.status = HKF_STATUS_MATCHED;
798: lineinfo.match |= HKF_MATCH_HOST |
799: (hashed ? HKF_MATCH_HOST_HASHED : 0);
800: }
801: /* Try matching IP address if supplied */
802: if (ip != NULL) {
803: if ((s = match_maybe_hashed(ip, lineinfo.hosts,
804: &hashed)) == -1) {
1.86 ! djm 805: debug2_f("%s:%ld: bad ip hash "
! 806: "\"%.32s\"", path, linenum,
! 807: lineinfo.hosts);
1.64 djm 808: goto bad;
809: }
810: if (s == 1) {
811: lineinfo.status = HKF_STATUS_MATCHED;
812: lineinfo.match |= HKF_MATCH_IP |
813: (hashed ? HKF_MATCH_IP_HASHED : 0);
814: }
815: }
816: /*
817: * Skip this line if host matching requested and
818: * neither host nor address matched.
819: */
820: if ((options & HKF_WANT_MATCH) != 0 &&
821: lineinfo.status != HKF_STATUS_MATCHED)
822: continue;
1.60 djm 823: }
824:
825: /* Got a match. Skip host name and any following whitespace */
826: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
827: ;
828: if (*cp2 == '\0' || *cp2 == '#') {
1.64 djm 829: debug2("%s:%ld: truncated before key type",
830: path, linenum);
1.60 djm 831: goto bad;
832: }
833: lineinfo.rawkey = cp = cp2;
834:
835: if ((options & HKF_WANT_PARSE_KEY) != 0) {
836: /*
837: * Extract the key from the line. This will skip
838: * any leading whitespace. Ignore badly formatted
839: * lines.
840: */
841: if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
1.86 ! djm 842: error_f("sshkey_new failed");
1.64 djm 843: r = SSH_ERR_ALLOC_FAIL;
844: break;
1.60 djm 845: }
846: if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
847: goto bad;
848: }
1.64 djm 849: lineinfo.keytype = lineinfo.key->type;
850: lineinfo.comment = cp;
851: } else {
852: /* Extract and parse key type */
853: l = strcspn(lineinfo.rawkey, " \t");
854: if (l <= 1 || l >= sizeof(ktype) ||
855: lineinfo.rawkey[l] == '\0')
856: goto bad;
857: memcpy(ktype, lineinfo.rawkey, l);
858: ktype[l] = '\0';
859: lineinfo.keytype = sshkey_type_from_name(ktype);
1.65 djm 860:
1.64 djm 861: /*
1.70 djm 862: * Assume legacy RSA1 if the first component is a short
1.64 djm 863: * decimal number.
864: */
865: if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
866: strspn(ktype, "0123456789") == l)
1.70 djm 867: goto bad;
1.65 djm 868:
1.64 djm 869: /*
870: * Check that something other than whitespace follows
871: * the key type. This won't catch all corruption, but
872: * it does catch trivial truncation.
873: */
874: cp2 += l; /* Skip past key type */
875: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
876: ;
877: if (*cp2 == '\0' || *cp2 == '#') {
878: debug2("%s:%ld: truncated after key type",
879: path, linenum);
880: lineinfo.keytype = KEY_UNSPEC;
881: }
882: if (lineinfo.keytype == KEY_UNSPEC) {
1.60 djm 883: bad:
1.64 djm 884: sshkey_free(lineinfo.key);
885: lineinfo.key = NULL;
1.60 djm 886: lineinfo.status = HKF_STATUS_INVALID;
887: if ((r = callback(&lineinfo, ctx)) != 0)
888: break;
889: continue;
890: }
891: }
892: if ((r = callback(&lineinfo, ctx)) != 0)
893: break;
894: }
895: sshkey_free(lineinfo.key);
1.72 markus 896: free(lineinfo.line);
897: free(line);
1.60 djm 898: fclose(f);
899: return r;
1.1 deraadt 900: }
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