Annotation of src/usr.bin/ssh/hostfile.c, Revision 1.84
1.84 ! djm 1: /* $OpenBSD: hostfile.c,v 1.83 2020/10/04 09:45:01 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)))
142: fatal("%s: ssh_hmac failed", __func__);
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)
1.54 markus 147: fatal("%s: __b64_ntop failed", __func__);
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:
1.61 djm 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);
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)
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);
1.58 djm 286: }
1.49 djm 287:
288: void
289: free_hostkeys(struct hostkeys *hostkeys)
290: {
291: u_int i;
292:
293: for (i = 0; i < hostkeys->num_entries; i++) {
1.51 djm 294: free(hostkeys->entries[i].host);
295: free(hostkeys->entries[i].file);
1.59 djm 296: sshkey_free(hostkeys->entries[i].key);
1.55 tedu 297: explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries));
1.49 djm 298: }
1.51 djm 299: free(hostkeys->entries);
1.78 jsg 300: freezero(hostkeys, sizeof(*hostkeys));
1.49 djm 301: }
302:
303: static int
1.59 djm 304: check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k)
1.49 djm 305: {
1.59 djm 306: int is_cert = sshkey_is_cert(k);
1.49 djm 307: u_int i;
1.7 markus 308:
1.49 djm 309: for (i = 0; i < hostkeys->num_entries; i++) {
310: if (hostkeys->entries[i].marker != MRK_REVOKE)
1.30 markus 311: continue;
1.59 djm 312: if (sshkey_equal_public(k, hostkeys->entries[i].key))
1.49 djm 313: return -1;
1.79 markus 314: if (is_cert && k != NULL &&
1.59 djm 315: sshkey_equal_public(k->cert->signature_key,
1.49 djm 316: hostkeys->entries[i].key))
317: return -1;
318: }
319: return 0;
320: }
321:
322: /*
323: * Match keys against a specified key, or look one up by key type.
324: *
325: * If looking for a keytype (key == NULL) and one is found then return
326: * HOST_FOUND, otherwise HOST_NEW.
327: *
328: * If looking for a key (key != NULL):
329: * 1. If the key is a cert and a matching CA is found, return HOST_OK
330: * 2. If the key is not a cert and a matching key is found, return HOST_OK
331: * 3. If no key matches but a key with a different type is found, then
332: * return HOST_CHANGED
333: * 4. If no matching keys are found, then return HOST_NEW.
334: *
335: * Finally, check any found key is not revoked.
336: */
337: static HostStatus
338: check_hostkeys_by_key_or_type(struct hostkeys *hostkeys,
1.83 djm 339: struct sshkey *k, int keytype, int nid, const struct hostkey_entry **found)
1.49 djm 340: {
341: u_int i;
342: HostStatus end_return = HOST_NEW;
1.59 djm 343: int want_cert = sshkey_is_cert(k);
1.49 djm 344: HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE;
345:
346: if (found != NULL)
347: *found = NULL;
1.30 markus 348:
1.49 djm 349: for (i = 0; i < hostkeys->num_entries; i++) {
350: if (hostkeys->entries[i].marker != want_marker)
351: continue;
352: if (k == NULL) {
353: if (hostkeys->entries[i].key->type != keytype)
354: continue;
1.83 djm 355: if (nid != -1 &&
356: sshkey_type_plain(keytype) == KEY_ECDSA &&
357: hostkeys->entries[i].key->ecdsa_nid != nid)
358: continue;
1.49 djm 359: end_return = HOST_FOUND;
360: if (found != NULL)
361: *found = hostkeys->entries + i;
362: k = hostkeys->entries[i].key;
363: break;
364: }
365: if (want_cert) {
1.59 djm 366: if (sshkey_equal_public(k->cert->signature_key,
1.49 djm 367: hostkeys->entries[i].key)) {
368: /* A matching CA exists */
369: end_return = HOST_OK;
370: if (found != NULL)
371: *found = hostkeys->entries + i;
372: break;
1.48 djm 373: }
1.49 djm 374: } else {
1.59 djm 375: if (sshkey_equal(k, hostkeys->entries[i].key)) {
1.49 djm 376: end_return = HOST_OK;
377: if (found != NULL)
378: *found = hostkeys->entries + i;
379: break;
1.48 djm 380: }
1.49 djm 381: /* A non-maching key exists */
382: end_return = HOST_CHANGED;
383: if (found != NULL)
384: *found = hostkeys->entries + i;
1.48 djm 385: }
1.1 deraadt 386: }
1.49 djm 387: if (check_key_not_revoked(hostkeys, k) != 0) {
388: end_return = HOST_REVOKED;
389: if (found != NULL)
390: *found = NULL;
391: }
1.7 markus 392: return end_return;
1.30 markus 393: }
1.58 djm 394:
1.30 markus 395: HostStatus
1.59 djm 396: check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key,
1.49 djm 397: const struct hostkey_entry **found)
1.30 markus 398: {
399: if (key == NULL)
400: fatal("no key to look up");
1.83 djm 401: return check_hostkeys_by_key_or_type(hostkeys, key, 0, -1, found);
1.30 markus 402: }
403:
404: int
1.83 djm 405: lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, int nid,
1.49 djm 406: const struct hostkey_entry **found)
1.30 markus 407: {
1.83 djm 408: return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, nid,
1.49 djm 409: found) == HOST_FOUND);
1.80 djm 410: }
411:
412: int
413: lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker)
414: {
415: u_int i;
416:
417: for (i = 0; i < hostkeys->num_entries; i++) {
418: if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker)
419: return 1;
420: }
421: return 0;
1.1 deraadt 422: }
423:
1.62 djm 424: static int
1.64 djm 425: write_host_entry(FILE *f, const char *host, const char *ip,
1.62 djm 426: const struct sshkey *key, int store_hash)
427: {
428: int r, success = 0;
1.68 djm 429: char *hashed_host = NULL, *lhost;
430:
431: lhost = xstrdup(host);
432: lowercase(lhost);
1.62 djm 433:
434: if (store_hash) {
1.68 djm 435: if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) {
1.62 djm 436: error("%s: host_hash failed", __func__);
1.68 djm 437: free(lhost);
1.62 djm 438: return 0;
439: }
1.64 djm 440: fprintf(f, "%s ", hashed_host);
441: } else if (ip != NULL)
1.68 djm 442: fprintf(f, "%s,%s ", lhost, ip);
443: else {
444: fprintf(f, "%s ", lhost);
445: }
446: free(lhost);
1.62 djm 447: if ((r = sshkey_write(key, f)) == 0)
448: success = 1;
449: else
450: error("%s: sshkey_write failed: %s", __func__, ssh_err(r));
451: fputc('\n', f);
1.84 ! djm 452: /* If hashing is enabled, the IP address needs to go on its own line */
! 453: if (success && store_hash && ip != NULL)
! 454: success = write_host_entry(f, ip, NULL, key, 1);
1.62 djm 455: return success;
456: }
457:
1.9 markus 458: /*
1.81 dtucker 459: * Create user ~/.ssh directory if it doesn't exist and we want to write to it.
460: * If notify is set, a message will be emitted if the directory is created.
461: */
462: void
463: hostfile_create_user_ssh_dir(const char *filename, int notify)
464: {
465: char *dotsshdir = NULL, *p;
466: size_t len;
467: struct stat st;
468:
469: if ((p = strrchr(filename, '/')) == NULL)
470: return;
471: len = p - filename;
472: dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid());
1.82 djm 473: if (strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0)
474: goto out; /* not ~/.ssh prefixed */
475: if (stat(dotsshdir, &st) == 0)
476: goto out; /* dir already exists */
1.81 dtucker 477: else if (errno != ENOENT)
478: error("Could not stat %s: %s", dotsshdir, strerror(errno));
1.82 djm 479: else {
480: if (mkdir(dotsshdir, 0700) == -1)
481: error("Could not create directory '%.200s' (%s).",
482: dotsshdir, strerror(errno));
483: else if (notify)
484: logit("Created directory '%s'.", dotsshdir);
485: }
486: out:
1.81 dtucker 487: free(dotsshdir);
488: }
1.82 djm 489:
1.81 dtucker 490:
491: /*
1.9 markus 492: * Appends an entry to the host file. Returns false if the entry could not
493: * be appended.
494: */
1.2 provos 495: int
1.59 djm 496: add_host_to_hostfile(const char *filename, const char *host,
497: const struct sshkey *key, int store_hash)
1.1 deraadt 498: {
1.7 markus 499: FILE *f;
1.62 djm 500: int success;
1.33 djm 501:
1.14 markus 502: if (key == NULL)
1.17 markus 503: return 1; /* XXX ? */
1.81 dtucker 504: hostfile_create_user_ssh_dir(filename, 0);
1.7 markus 505: f = fopen(filename, "a");
506: if (!f)
507: return 0;
1.64 djm 508: success = write_host_entry(f, host, NULL, key, store_hash);
1.62 djm 509: fclose(f);
510: return success;
511: }
512:
513: struct host_delete_ctx {
514: FILE *out;
515: int quiet;
516: const char *host;
1.64 djm 517: int *skip_keys; /* XXX split for host/ip? might want to ensure both */
1.62 djm 518: struct sshkey * const *keys;
519: size_t nkeys;
1.64 djm 520: int modified;
1.62 djm 521: };
522:
523: static int
524: host_delete(struct hostkey_foreach_line *l, void *_ctx)
525: {
526: struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx;
1.64 djm 527: int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 528: size_t i;
529:
1.64 djm 530: if (l->status == HKF_STATUS_MATCHED) {
1.62 djm 531: if (l->marker != MRK_NONE) {
532: /* Don't remove CA and revocation lines */
533: fprintf(ctx->out, "%s\n", l->line);
534: return 0;
535: }
1.33 djm 536:
1.62 djm 537: /*
538: * If this line contains one of the keys that we will be
539: * adding later, then don't change it and mark the key for
540: * skipping.
541: */
542: for (i = 0; i < ctx->nkeys; i++) {
543: if (sshkey_equal(ctx->keys[i], l->key)) {
544: ctx->skip_keys[i] = 1;
545: fprintf(ctx->out, "%s\n", l->line);
546: debug3("%s: %s key already at %s:%ld", __func__,
547: sshkey_type(l->key), l->path, l->linenum);
548: return 0;
549: }
550: }
551:
552: /*
553: * Hostname matches and has no CA/revoke marker, delete it
554: * by *not* writing the line to ctx->out.
555: */
1.64 djm 556: do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
1.62 djm 557: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
1.64 djm 558: l->path, l->linenum, sshkey_type(l->key), ctx->host);
559: ctx->modified = 1;
1.62 djm 560: return 0;
561: }
562: /* Retain non-matching hosts and invalid lines when deleting */
563: if (l->status == HKF_STATUS_INVALID) {
564: do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry",
565: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
566: l->path, l->linenum);
567: }
568: fprintf(ctx->out, "%s\n", l->line);
569: return 0;
570: }
571:
572: int
1.64 djm 573: hostfile_replace_entries(const char *filename, const char *host, const char *ip,
574: struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg)
1.62 djm 575: {
576: int r, fd, oerrno = 0;
1.64 djm 577: int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 578: struct host_delete_ctx ctx;
1.64 djm 579: char *fp, *temp = NULL, *back = NULL;
1.62 djm 580: mode_t omask;
581: size_t i;
582:
1.63 djm 583: omask = umask(077);
584:
1.62 djm 585: memset(&ctx, 0, sizeof(ctx));
586: ctx.host = host;
587: ctx.quiet = quiet;
588: if ((ctx.skip_keys = calloc(nkeys, sizeof(*ctx.skip_keys))) == NULL)
589: return SSH_ERR_ALLOC_FAIL;
590: ctx.keys = keys;
591: ctx.nkeys = nkeys;
1.64 djm 592: ctx.modified = 0;
1.62 djm 593:
594: /*
595: * Prepare temporary file for in-place deletion.
596: */
1.75 deraadt 597: if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 ||
1.74 deraadt 598: (r = asprintf(&back, "%s.old", filename)) == -1) {
1.62 djm 599: r = SSH_ERR_ALLOC_FAIL;
600: goto fail;
601: }
602:
603: if ((fd = mkstemp(temp)) == -1) {
604: oerrno = errno;
605: error("%s: mkstemp: %s", __func__, strerror(oerrno));
606: r = SSH_ERR_SYSTEM_ERROR;
607: goto fail;
608: }
609: if ((ctx.out = fdopen(fd, "w")) == NULL) {
610: oerrno = errno;
611: close(fd);
612: error("%s: fdopen: %s", __func__, strerror(oerrno));
613: r = SSH_ERR_SYSTEM_ERROR;
614: goto fail;
615: }
616:
617: /* Remove all entries for the specified host from the file */
1.64 djm 618: if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
1.62 djm 619: HKF_WANT_PARSE_KEY)) != 0) {
1.77 djm 620: oerrno = errno;
1.62 djm 621: error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r));
622: goto fail;
623: }
624:
625: /* Add the requested keys */
626: for (i = 0; i < nkeys; i++) {
627: if (ctx.skip_keys[i])
628: continue;
1.64 djm 629: if ((fp = sshkey_fingerprint(keys[i], hash_alg,
630: SSH_FP_DEFAULT)) == NULL) {
631: r = SSH_ERR_ALLOC_FAIL;
632: goto fail;
633: }
634: do_log2(loglevel, "%s%sAdding new key for %s to %s: %s %s",
635: quiet ? __func__ : "", quiet ? ": " : "", host, filename,
636: sshkey_ssh_name(keys[i]), fp);
637: free(fp);
638: if (!write_host_entry(ctx.out, host, ip, keys[i], store_hash)) {
1.62 djm 639: r = SSH_ERR_INTERNAL_ERROR;
640: goto fail;
641: }
1.64 djm 642: ctx.modified = 1;
1.33 djm 643: }
1.62 djm 644: fclose(ctx.out);
645: ctx.out = NULL;
1.33 djm 646:
1.64 djm 647: if (ctx.modified) {
648: /* Backup the original file and replace it with the temporary */
649: if (unlink(back) == -1 && errno != ENOENT) {
650: oerrno = errno;
651: error("%s: unlink %.100s: %s", __func__,
652: back, strerror(errno));
653: r = SSH_ERR_SYSTEM_ERROR;
654: goto fail;
655: }
656: if (link(filename, back) == -1) {
657: oerrno = errno;
658: error("%s: link %.100s to %.100s: %s", __func__,
659: filename, back, strerror(errno));
660: r = SSH_ERR_SYSTEM_ERROR;
661: goto fail;
662: }
663: if (rename(temp, filename) == -1) {
664: oerrno = errno;
665: error("%s: rename \"%s\" to \"%s\": %s", __func__,
666: temp, filename, strerror(errno));
667: r = SSH_ERR_SYSTEM_ERROR;
668: goto fail;
669: }
670: } else {
671: /* No changes made; just delete the temporary file */
672: if (unlink(temp) != 0)
673: error("%s: unlink \"%s\": %s", __func__,
674: temp, strerror(errno));
1.62 djm 675: }
1.64 djm 676:
1.62 djm 677: /* success */
678: r = 0;
679: fail:
680: if (temp != NULL && r != 0)
681: unlink(temp);
682: free(temp);
683: free(back);
684: if (ctx.out != NULL)
685: fclose(ctx.out);
686: free(ctx.skip_keys);
1.63 djm 687: umask(omask);
1.62 djm 688: if (r == SSH_ERR_SYSTEM_ERROR)
689: errno = oerrno;
690: return r;
1.60 djm 691: }
692:
693: static int
694: match_maybe_hashed(const char *host, const char *names, int *was_hashed)
695: {
696: int hashed = *names == HASH_DELIM;
697: const char *hashed_host;
698: size_t nlen = strlen(names);
699:
700: if (was_hashed != NULL)
701: *was_hashed = hashed;
702: if (hashed) {
703: if ((hashed_host = host_hash(host, names, nlen)) == NULL)
704: return -1;
705: return nlen == strlen(hashed_host) &&
706: strncmp(hashed_host, names, nlen) == 0;
707: }
1.66 djm 708: return match_hostname(host, names) == 1;
1.60 djm 709: }
710:
711: int
712: hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
1.64 djm 713: const char *host, const char *ip, u_int options)
1.60 djm 714: {
715: FILE *f;
1.72 markus 716: char *line = NULL, ktype[128];
1.60 djm 717: u_long linenum = 0;
718: char *cp, *cp2;
719: u_int kbits;
1.64 djm 720: int hashed;
1.60 djm 721: int s, r = 0;
722: struct hostkey_foreach_line lineinfo;
1.72 markus 723: size_t linesize = 0, l;
1.60 djm 724:
725: memset(&lineinfo, 0, sizeof(lineinfo));
1.64 djm 726: if (host == NULL && (options & HKF_WANT_MATCH) != 0)
1.60 djm 727: return SSH_ERR_INVALID_ARGUMENT;
728: if ((f = fopen(path, "r")) == NULL)
729: return SSH_ERR_SYSTEM_ERROR;
730:
731: debug3("%s: reading file \"%s\"", __func__, path);
1.72 markus 732: while (getline(&line, &linesize, f) != -1) {
733: linenum++;
1.60 djm 734: line[strcspn(line, "\n")] = '\0';
735:
1.73 djm 736: free(lineinfo.line);
1.60 djm 737: sshkey_free(lineinfo.key);
738: memset(&lineinfo, 0, sizeof(lineinfo));
739: lineinfo.path = path;
740: lineinfo.linenum = linenum;
1.72 markus 741: lineinfo.line = xstrdup(line);
1.64 djm 742: lineinfo.marker = MRK_NONE;
1.60 djm 743: lineinfo.status = HKF_STATUS_OK;
1.64 djm 744: lineinfo.keytype = KEY_UNSPEC;
1.60 djm 745:
746: /* Skip any leading whitespace, comments and empty lines. */
747: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
748: ;
749: if (!*cp || *cp == '#' || *cp == '\n') {
1.64 djm 750: if ((options & HKF_WANT_MATCH) == 0) {
1.60 djm 751: lineinfo.status = HKF_STATUS_COMMENT;
752: if ((r = callback(&lineinfo, ctx)) != 0)
753: break;
754: }
755: continue;
756: }
757:
758: if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
759: verbose("%s: invalid marker at %s:%lu",
760: __func__, path, linenum);
1.64 djm 761: if ((options & HKF_WANT_MATCH) == 0)
1.60 djm 762: goto bad;
763: continue;
764: }
765:
766: /* Find the end of the host name portion. */
767: for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
768: ;
769: lineinfo.hosts = cp;
770: *cp2++ = '\0';
771:
772: /* Check if the host name matches. */
773: if (host != NULL) {
1.64 djm 774: if ((s = match_maybe_hashed(host, lineinfo.hosts,
775: &hashed)) == -1) {
1.60 djm 776: debug2("%s: %s:%ld: bad host hash \"%.32s\"",
777: __func__, path, linenum, lineinfo.hosts);
778: goto bad;
779: }
1.64 djm 780: if (s == 1) {
781: lineinfo.status = HKF_STATUS_MATCHED;
782: lineinfo.match |= HKF_MATCH_HOST |
783: (hashed ? HKF_MATCH_HOST_HASHED : 0);
784: }
785: /* Try matching IP address if supplied */
786: if (ip != NULL) {
787: if ((s = match_maybe_hashed(ip, lineinfo.hosts,
788: &hashed)) == -1) {
789: debug2("%s: %s:%ld: bad ip hash "
790: "\"%.32s\"", __func__, path,
791: linenum, lineinfo.hosts);
792: goto bad;
793: }
794: if (s == 1) {
795: lineinfo.status = HKF_STATUS_MATCHED;
796: lineinfo.match |= HKF_MATCH_IP |
797: (hashed ? HKF_MATCH_IP_HASHED : 0);
798: }
799: }
800: /*
801: * Skip this line if host matching requested and
802: * neither host nor address matched.
803: */
804: if ((options & HKF_WANT_MATCH) != 0 &&
805: lineinfo.status != HKF_STATUS_MATCHED)
806: continue;
1.60 djm 807: }
808:
809: /* Got a match. Skip host name and any following whitespace */
810: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
811: ;
812: if (*cp2 == '\0' || *cp2 == '#') {
1.64 djm 813: debug2("%s:%ld: truncated before key type",
814: path, linenum);
1.60 djm 815: goto bad;
816: }
817: lineinfo.rawkey = cp = cp2;
818:
819: if ((options & HKF_WANT_PARSE_KEY) != 0) {
820: /*
821: * Extract the key from the line. This will skip
822: * any leading whitespace. Ignore badly formatted
823: * lines.
824: */
825: if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
826: error("%s: sshkey_new failed", __func__);
1.64 djm 827: r = SSH_ERR_ALLOC_FAIL;
828: break;
1.60 djm 829: }
830: if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
831: goto bad;
832: }
1.64 djm 833: lineinfo.keytype = lineinfo.key->type;
834: lineinfo.comment = cp;
835: } else {
836: /* Extract and parse key type */
837: l = strcspn(lineinfo.rawkey, " \t");
838: if (l <= 1 || l >= sizeof(ktype) ||
839: lineinfo.rawkey[l] == '\0')
840: goto bad;
841: memcpy(ktype, lineinfo.rawkey, l);
842: ktype[l] = '\0';
843: lineinfo.keytype = sshkey_type_from_name(ktype);
1.65 djm 844:
1.64 djm 845: /*
1.70 djm 846: * Assume legacy RSA1 if the first component is a short
1.64 djm 847: * decimal number.
848: */
849: if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
850: strspn(ktype, "0123456789") == l)
1.70 djm 851: goto bad;
1.65 djm 852:
1.64 djm 853: /*
854: * Check that something other than whitespace follows
855: * the key type. This won't catch all corruption, but
856: * it does catch trivial truncation.
857: */
858: cp2 += l; /* Skip past key type */
859: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
860: ;
861: if (*cp2 == '\0' || *cp2 == '#') {
862: debug2("%s:%ld: truncated after key type",
863: path, linenum);
864: lineinfo.keytype = KEY_UNSPEC;
865: }
866: if (lineinfo.keytype == KEY_UNSPEC) {
1.60 djm 867: bad:
1.64 djm 868: sshkey_free(lineinfo.key);
869: lineinfo.key = NULL;
1.60 djm 870: lineinfo.status = HKF_STATUS_INVALID;
871: if ((r = callback(&lineinfo, ctx)) != 0)
872: break;
873: continue;
874: }
875: }
876: if ((r = callback(&lineinfo, ctx)) != 0)
877: break;
878: }
879: sshkey_free(lineinfo.key);
1.72 markus 880: free(lineinfo.line);
881: free(line);
1.60 djm 882: fclose(f);
883: return r;
1.1 deraadt 884: }
![[BACK]](/icons/back.gif){kind=icon}
Return to hostfile.c CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh