Annotation of src/usr.bin/ssh/hostfile.c, Revision 1.90
1.90 ! djm 1: /* $OpenBSD: hostfile.c,v 1.89 2021/01/26 00:51:30 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"
1.88 djm 62: #include "sshbuf.h"
1.33 djm 63:
1.60 djm 64: /* XXX hmac is too easy to dictionary attack; use bcrypt? */
65:
1.33 djm 66: static int
1.52 djm 67: extract_salt(const char *s, u_int l, u_char *salt, size_t salt_len)
1.33 djm 68: {
69: char *p, *b64salt;
70: u_int b64len;
71: int ret;
72:
73: if (l < sizeof(HASH_MAGIC) - 1) {
74: debug2("extract_salt: string too short");
75: return (-1);
76: }
77: if (strncmp(s, HASH_MAGIC, sizeof(HASH_MAGIC) - 1) != 0) {
78: debug2("extract_salt: invalid magic identifier");
79: return (-1);
80: }
81: s += sizeof(HASH_MAGIC) - 1;
82: l -= sizeof(HASH_MAGIC) - 1;
83: if ((p = memchr(s, HASH_DELIM, l)) == NULL) {
84: debug2("extract_salt: missing salt termination character");
85: return (-1);
86: }
87:
88: b64len = p - s;
89: /* Sanity check */
90: if (b64len == 0 || b64len > 1024) {
91: debug2("extract_salt: bad encoded salt length %u", b64len);
92: return (-1);
93: }
94: b64salt = xmalloc(1 + b64len);
95: memcpy(b64salt, s, b64len);
96: b64salt[b64len] = '\0';
97:
98: ret = __b64_pton(b64salt, salt, salt_len);
1.51 djm 99: free(b64salt);
1.33 djm 100: if (ret == -1) {
101: debug2("extract_salt: salt decode error");
102: return (-1);
103: }
1.54 markus 104: if (ret != (int)ssh_hmac_bytes(SSH_DIGEST_SHA1)) {
105: debug2("extract_salt: expected salt len %zd, got %d",
106: ssh_hmac_bytes(SSH_DIGEST_SHA1), ret);
1.33 djm 107: return (-1);
108: }
1.34 deraadt 109:
1.33 djm 110: return (0);
111: }
112:
113: char *
114: host_hash(const char *host, const char *name_from_hostfile, u_int src_len)
115: {
1.54 markus 116: struct ssh_hmac_ctx *ctx;
1.52 djm 117: u_char salt[256], result[256];
118: char uu_salt[512], uu_result[512];
1.33 djm 119: static char encoded[1024];
1.67 tedu 120: u_int len;
1.33 djm 121:
1.54 markus 122: len = ssh_digest_bytes(SSH_DIGEST_SHA1);
1.33 djm 123:
124: if (name_from_hostfile == NULL) {
125: /* Create new salt */
1.67 tedu 126: arc4random_buf(salt, len);
1.33 djm 127: } else {
128: /* Extract salt from known host entry */
129: if (extract_salt(name_from_hostfile, src_len, salt,
130: sizeof(salt)) == -1)
131: return (NULL);
132: }
133:
1.54 markus 134: if ((ctx = ssh_hmac_start(SSH_DIGEST_SHA1)) == NULL ||
135: ssh_hmac_init(ctx, salt, len) < 0 ||
136: ssh_hmac_update(ctx, host, strlen(host)) < 0 ||
137: ssh_hmac_final(ctx, result, sizeof(result)))
1.86 djm 138: fatal_f("ssh_hmac failed");
1.54 markus 139: ssh_hmac_free(ctx);
1.33 djm 140:
1.34 deraadt 141: if (__b64_ntop(salt, len, uu_salt, sizeof(uu_salt)) == -1 ||
1.33 djm 142: __b64_ntop(result, len, uu_result, sizeof(uu_result)) == -1)
1.86 djm 143: fatal_f("__b64_ntop failed");
1.33 djm 144:
145: snprintf(encoded, sizeof(encoded), "%s%s%c%s", HASH_MAGIC, uu_salt,
146: HASH_DELIM, uu_result);
147:
148: return (encoded);
149: }
1.1 deraadt 150:
1.9 markus 151: /*
1.14 markus 152: * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the
153: * pointer over the key. Skips any whitespace at the beginning and at end.
1.9 markus 154: */
1.1 deraadt 155:
1.29 jakob 156: int
1.59 djm 157: hostfile_read_key(char **cpp, u_int *bitsp, struct sshkey *ret)
1.1 deraadt 158: {
1.7 markus 159: char *cp;
160:
161: /* Skip leading whitespace. */
1.9 markus 162: for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
163: ;
1.1 deraadt 164:
1.76 dtucker 165: if (sshkey_read(ret, &cp) != 0)
1.7 markus 166: return 0;
167:
168: /* Skip trailing whitespace. */
1.9 markus 169: for (; *cp == ' ' || *cp == '\t'; cp++)
170: ;
1.7 markus 171:
172: /* Return results. */
173: *cpp = cp;
1.59 djm 174: if (bitsp != NULL)
175: *bitsp = sshkey_size(ret);
1.7 markus 176: return 1;
1.14 markus 177: }
1.1 deraadt 178:
1.49 djm 179: static HostkeyMarker
1.48 djm 180: check_markers(char **cpp)
181: {
182: char marker[32], *sp, *cp = *cpp;
183: int ret = MRK_NONE;
184:
185: while (*cp == '@') {
186: /* Only one marker is allowed */
187: if (ret != MRK_NONE)
188: return MRK_ERROR;
189: /* Markers are terminated by whitespace */
190: if ((sp = strchr(cp, ' ')) == NULL &&
191: (sp = strchr(cp, '\t')) == NULL)
192: return MRK_ERROR;
193: /* Extract marker for comparison */
194: if (sp <= cp + 1 || sp >= cp + sizeof(marker))
195: return MRK_ERROR;
196: memcpy(marker, cp, sp - cp);
197: marker[sp - cp] = '\0';
198: if (strcmp(marker, CA_MARKER) == 0)
199: ret = MRK_CA;
200: else if (strcmp(marker, REVOKE_MARKER) == 0)
201: ret = MRK_REVOKE;
202: else
203: return MRK_ERROR;
204:
205: /* Skip past marker and any whitespace that follows it */
206: cp = sp;
207: for (; *cp == ' ' || *cp == '\t'; cp++)
208: ;
209: }
210: *cpp = cp;
211: return ret;
212: }
213:
1.49 djm 214: struct hostkeys *
215: init_hostkeys(void)
216: {
217: struct hostkeys *ret = xcalloc(1, sizeof(*ret));
218:
219: ret->entries = NULL;
220: return ret;
221: }
1.1 deraadt 222:
1.61 djm 223: struct load_callback_ctx {
224: const char *host;
225: u_long num_loaded;
226: struct hostkeys *hostkeys;
227: };
228:
229: static int
230: record_hostkey(struct hostkey_foreach_line *l, void *_ctx)
1.1 deraadt 231: {
1.61 djm 232: struct load_callback_ctx *ctx = (struct load_callback_ctx *)_ctx;
233: struct hostkeys *hostkeys = ctx->hostkeys;
234: struct hostkey_entry *tmp;
235:
236: if (l->status == HKF_STATUS_INVALID) {
1.65 djm 237: /* XXX make this verbose() in the future */
238: debug("%s:%ld: parse error in hostkeys file",
1.61 djm 239: l->path, l->linenum);
240: return 0;
241: }
1.7 markus 242:
1.86 djm 243: debug3_f("found %skey type %s in file %s:%lu",
1.61 djm 244: l->marker == MRK_NONE ? "" :
245: (l->marker == MRK_CA ? "ca " : "revoked "),
246: sshkey_type(l->key), l->path, l->linenum);
1.71 deraadt 247: if ((tmp = recallocarray(hostkeys->entries, hostkeys->num_entries,
1.61 djm 248: hostkeys->num_entries + 1, sizeof(*hostkeys->entries))) == NULL)
249: return SSH_ERR_ALLOC_FAIL;
250: hostkeys->entries = tmp;
251: hostkeys->entries[hostkeys->num_entries].host = xstrdup(ctx->host);
252: hostkeys->entries[hostkeys->num_entries].file = xstrdup(l->path);
253: hostkeys->entries[hostkeys->num_entries].line = l->linenum;
254: hostkeys->entries[hostkeys->num_entries].key = l->key;
255: l->key = NULL; /* steal it */
256: hostkeys->entries[hostkeys->num_entries].marker = l->marker;
1.87 djm 257: hostkeys->entries[hostkeys->num_entries].note = l->note;
1.61 djm 258: hostkeys->num_entries++;
259: ctx->num_loaded++;
1.7 markus 260:
1.61 djm 261: return 0;
262: }
1.47 djm 263:
1.61 djm 264: void
1.87 djm 265: load_hostkeys_file(struct hostkeys *hostkeys, const char *host,
266: const char *path, FILE *f, u_int note)
1.61 djm 267: {
268: int r;
269: struct load_callback_ctx ctx;
1.7 markus 270:
1.61 djm 271: ctx.host = host;
272: ctx.num_loaded = 0;
273: ctx.hostkeys = hostkeys;
274:
1.87 djm 275: if ((r = hostkeys_foreach_file(path, f, record_hostkey, &ctx, host,
276: NULL, HKF_WANT_MATCH|HKF_WANT_PARSE_KEY, note)) != 0) {
1.61 djm 277: if (r != SSH_ERR_SYSTEM_ERROR && errno != ENOENT)
1.86 djm 278: debug_fr(r, "hostkeys_foreach failed for %s", path);
1.61 djm 279: }
280: if (ctx.num_loaded != 0)
1.86 djm 281: debug3_f("loaded %lu keys from %s", ctx.num_loaded, host);
1.58 djm 282: }
1.49 djm 283:
284: void
1.87 djm 285: load_hostkeys(struct hostkeys *hostkeys, const char *host, const char *path,
286: u_int note)
287: {
288: FILE *f;
289:
290: if ((f = fopen(path, "r")) == NULL) {
291: debug_f("fopen %s: %s", path, strerror(errno));
292: return;
293: }
294:
295: load_hostkeys_file(hostkeys, host, path, f, note);
296: fclose(f);
297: }
298:
299: void
1.49 djm 300: free_hostkeys(struct hostkeys *hostkeys)
301: {
302: u_int i;
303:
304: for (i = 0; i < hostkeys->num_entries; i++) {
1.51 djm 305: free(hostkeys->entries[i].host);
306: free(hostkeys->entries[i].file);
1.59 djm 307: sshkey_free(hostkeys->entries[i].key);
1.55 tedu 308: explicit_bzero(hostkeys->entries + i, sizeof(*hostkeys->entries));
1.49 djm 309: }
1.51 djm 310: free(hostkeys->entries);
1.78 jsg 311: freezero(hostkeys, sizeof(*hostkeys));
1.49 djm 312: }
313:
314: static int
1.59 djm 315: check_key_not_revoked(struct hostkeys *hostkeys, struct sshkey *k)
1.49 djm 316: {
1.59 djm 317: int is_cert = sshkey_is_cert(k);
1.49 djm 318: u_int i;
1.7 markus 319:
1.49 djm 320: for (i = 0; i < hostkeys->num_entries; i++) {
321: if (hostkeys->entries[i].marker != MRK_REVOKE)
1.30 markus 322: continue;
1.59 djm 323: if (sshkey_equal_public(k, hostkeys->entries[i].key))
1.49 djm 324: return -1;
1.79 markus 325: if (is_cert && k != NULL &&
1.59 djm 326: sshkey_equal_public(k->cert->signature_key,
1.49 djm 327: hostkeys->entries[i].key))
328: return -1;
329: }
330: return 0;
331: }
332:
333: /*
334: * Match keys against a specified key, or look one up by key type.
335: *
336: * If looking for a keytype (key == NULL) and one is found then return
337: * HOST_FOUND, otherwise HOST_NEW.
338: *
339: * If looking for a key (key != NULL):
340: * 1. If the key is a cert and a matching CA is found, return HOST_OK
341: * 2. If the key is not a cert and a matching key is found, return HOST_OK
342: * 3. If no key matches but a key with a different type is found, then
343: * return HOST_CHANGED
344: * 4. If no matching keys are found, then return HOST_NEW.
345: *
346: * Finally, check any found key is not revoked.
347: */
348: static HostStatus
349: check_hostkeys_by_key_or_type(struct hostkeys *hostkeys,
1.83 djm 350: struct sshkey *k, int keytype, int nid, const struct hostkey_entry **found)
1.49 djm 351: {
352: u_int i;
353: HostStatus end_return = HOST_NEW;
1.59 djm 354: int want_cert = sshkey_is_cert(k);
1.49 djm 355: HostkeyMarker want_marker = want_cert ? MRK_CA : MRK_NONE;
356:
357: if (found != NULL)
358: *found = NULL;
1.30 markus 359:
1.49 djm 360: for (i = 0; i < hostkeys->num_entries; i++) {
361: if (hostkeys->entries[i].marker != want_marker)
362: continue;
363: if (k == NULL) {
364: if (hostkeys->entries[i].key->type != keytype)
365: continue;
1.83 djm 366: if (nid != -1 &&
367: sshkey_type_plain(keytype) == KEY_ECDSA &&
368: hostkeys->entries[i].key->ecdsa_nid != nid)
369: continue;
1.49 djm 370: end_return = HOST_FOUND;
371: if (found != NULL)
372: *found = hostkeys->entries + i;
373: k = hostkeys->entries[i].key;
374: break;
375: }
376: if (want_cert) {
1.59 djm 377: if (sshkey_equal_public(k->cert->signature_key,
1.49 djm 378: hostkeys->entries[i].key)) {
379: /* A matching CA exists */
380: end_return = HOST_OK;
381: if (found != NULL)
382: *found = hostkeys->entries + i;
383: break;
1.48 djm 384: }
1.49 djm 385: } else {
1.59 djm 386: if (sshkey_equal(k, hostkeys->entries[i].key)) {
1.49 djm 387: end_return = HOST_OK;
388: if (found != NULL)
389: *found = hostkeys->entries + i;
390: break;
1.48 djm 391: }
1.90 ! djm 392: /* A non-matching key exists */
1.49 djm 393: end_return = HOST_CHANGED;
394: if (found != NULL)
395: *found = hostkeys->entries + i;
1.48 djm 396: }
1.1 deraadt 397: }
1.49 djm 398: if (check_key_not_revoked(hostkeys, k) != 0) {
399: end_return = HOST_REVOKED;
400: if (found != NULL)
401: *found = NULL;
402: }
1.7 markus 403: return end_return;
1.30 markus 404: }
1.58 djm 405:
1.30 markus 406: HostStatus
1.59 djm 407: check_key_in_hostkeys(struct hostkeys *hostkeys, struct sshkey *key,
1.49 djm 408: const struct hostkey_entry **found)
1.30 markus 409: {
410: if (key == NULL)
411: fatal("no key to look up");
1.83 djm 412: return check_hostkeys_by_key_or_type(hostkeys, key, 0, -1, found);
1.30 markus 413: }
414:
415: int
1.83 djm 416: lookup_key_in_hostkeys_by_type(struct hostkeys *hostkeys, int keytype, int nid,
1.49 djm 417: const struct hostkey_entry **found)
1.30 markus 418: {
1.83 djm 419: return (check_hostkeys_by_key_or_type(hostkeys, NULL, keytype, nid,
1.49 djm 420: found) == HOST_FOUND);
1.80 djm 421: }
422:
423: int
424: lookup_marker_in_hostkeys(struct hostkeys *hostkeys, int want_marker)
425: {
426: u_int i;
427:
428: for (i = 0; i < hostkeys->num_entries; i++) {
429: if (hostkeys->entries[i].marker == (HostkeyMarker)want_marker)
430: return 1;
431: }
432: return 0;
1.1 deraadt 433: }
434:
1.62 djm 435: static int
1.64 djm 436: write_host_entry(FILE *f, const char *host, const char *ip,
1.62 djm 437: const struct sshkey *key, int store_hash)
438: {
439: int r, success = 0;
1.68 djm 440: char *hashed_host = NULL, *lhost;
441:
442: lhost = xstrdup(host);
443: lowercase(lhost);
1.62 djm 444:
445: if (store_hash) {
1.68 djm 446: if ((hashed_host = host_hash(lhost, NULL, 0)) == NULL) {
1.86 djm 447: error_f("host_hash failed");
1.68 djm 448: free(lhost);
1.62 djm 449: return 0;
450: }
1.64 djm 451: fprintf(f, "%s ", hashed_host);
452: } else if (ip != NULL)
1.68 djm 453: fprintf(f, "%s,%s ", lhost, ip);
454: else {
455: fprintf(f, "%s ", lhost);
456: }
457: free(lhost);
1.62 djm 458: if ((r = sshkey_write(key, f)) == 0)
459: success = 1;
460: else
1.86 djm 461: error_fr(r, "sshkey_write");
1.62 djm 462: fputc('\n', f);
1.84 djm 463: /* If hashing is enabled, the IP address needs to go on its own line */
464: if (success && store_hash && ip != NULL)
465: success = write_host_entry(f, ip, NULL, key, 1);
1.62 djm 466: return success;
467: }
468:
1.9 markus 469: /*
1.81 dtucker 470: * Create user ~/.ssh directory if it doesn't exist and we want to write to it.
471: * If notify is set, a message will be emitted if the directory is created.
472: */
473: void
474: hostfile_create_user_ssh_dir(const char *filename, int notify)
475: {
476: char *dotsshdir = NULL, *p;
477: size_t len;
478: struct stat st;
479:
480: if ((p = strrchr(filename, '/')) == NULL)
481: return;
482: len = p - filename;
483: dotsshdir = tilde_expand_filename("~/" _PATH_SSH_USER_DIR, getuid());
1.82 djm 484: if (strlen(dotsshdir) > len || strncmp(filename, dotsshdir, len) != 0)
485: goto out; /* not ~/.ssh prefixed */
486: if (stat(dotsshdir, &st) == 0)
487: goto out; /* dir already exists */
1.81 dtucker 488: else if (errno != ENOENT)
489: error("Could not stat %s: %s", dotsshdir, strerror(errno));
1.82 djm 490: else {
491: if (mkdir(dotsshdir, 0700) == -1)
492: error("Could not create directory '%.200s' (%s).",
493: dotsshdir, strerror(errno));
494: else if (notify)
495: logit("Created directory '%s'.", dotsshdir);
496: }
497: out:
1.81 dtucker 498: free(dotsshdir);
499: }
1.82 djm 500:
1.81 dtucker 501:
502: /*
1.9 markus 503: * Appends an entry to the host file. Returns false if the entry could not
504: * be appended.
505: */
1.2 provos 506: int
1.59 djm 507: add_host_to_hostfile(const char *filename, const char *host,
508: const struct sshkey *key, int store_hash)
1.1 deraadt 509: {
1.7 markus 510: FILE *f;
1.62 djm 511: int success;
1.33 djm 512:
1.14 markus 513: if (key == NULL)
1.17 markus 514: return 1; /* XXX ? */
1.81 dtucker 515: hostfile_create_user_ssh_dir(filename, 0);
1.7 markus 516: f = fopen(filename, "a");
517: if (!f)
518: return 0;
1.64 djm 519: success = write_host_entry(f, host, NULL, key, store_hash);
1.62 djm 520: fclose(f);
521: return success;
522: }
523:
524: struct host_delete_ctx {
525: FILE *out;
526: int quiet;
1.85 djm 527: const char *host, *ip;
528: u_int *match_keys; /* mask of HKF_MATCH_* for this key */
1.62 djm 529: struct sshkey * const *keys;
530: size_t nkeys;
1.64 djm 531: int modified;
1.62 djm 532: };
533:
534: static int
535: host_delete(struct hostkey_foreach_line *l, void *_ctx)
536: {
537: struct host_delete_ctx *ctx = (struct host_delete_ctx *)_ctx;
1.64 djm 538: int loglevel = ctx->quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 539: size_t i;
540:
1.85 djm 541: /* Don't remove CA and revocation lines */
542: if (l->status == HKF_STATUS_MATCHED && l->marker == MRK_NONE) {
1.62 djm 543: /*
544: * If this line contains one of the keys that we will be
545: * adding later, then don't change it and mark the key for
546: * skipping.
547: */
548: for (i = 0; i < ctx->nkeys; i++) {
1.85 djm 549: if (!sshkey_equal(ctx->keys[i], l->key))
550: continue;
551: ctx->match_keys[i] |= l->match;
552: fprintf(ctx->out, "%s\n", l->line);
1.86 djm 553: debug3_f("%s key already at %s:%ld",
1.85 djm 554: sshkey_type(l->key), l->path, l->linenum);
555: return 0;
1.62 djm 556: }
557:
558: /*
559: * Hostname matches and has no CA/revoke marker, delete it
560: * by *not* writing the line to ctx->out.
561: */
1.64 djm 562: do_log2(loglevel, "%s%s%s:%ld: Removed %s key for host %s",
1.62 djm 563: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
1.64 djm 564: l->path, l->linenum, sshkey_type(l->key), ctx->host);
565: ctx->modified = 1;
1.62 djm 566: return 0;
567: }
568: /* Retain non-matching hosts and invalid lines when deleting */
569: if (l->status == HKF_STATUS_INVALID) {
570: do_log2(loglevel, "%s%s%s:%ld: invalid known_hosts entry",
571: ctx->quiet ? __func__ : "", ctx->quiet ? ": " : "",
572: l->path, l->linenum);
573: }
574: fprintf(ctx->out, "%s\n", l->line);
575: return 0;
576: }
577:
578: int
1.64 djm 579: hostfile_replace_entries(const char *filename, const char *host, const char *ip,
580: struct sshkey **keys, size_t nkeys, int store_hash, int quiet, int hash_alg)
1.62 djm 581: {
582: int r, fd, oerrno = 0;
1.64 djm 583: int loglevel = quiet ? SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_VERBOSE;
1.62 djm 584: struct host_delete_ctx ctx;
1.64 djm 585: char *fp, *temp = NULL, *back = NULL;
1.85 djm 586: const char *what;
1.62 djm 587: mode_t omask;
588: size_t i;
1.85 djm 589: u_int want;
1.62 djm 590:
1.63 djm 591: omask = umask(077);
592:
1.62 djm 593: memset(&ctx, 0, sizeof(ctx));
594: ctx.host = host;
1.85 djm 595: ctx.ip = ip;
1.62 djm 596: ctx.quiet = quiet;
1.85 djm 597:
598: if ((ctx.match_keys = calloc(nkeys, sizeof(*ctx.match_keys))) == NULL)
1.62 djm 599: return SSH_ERR_ALLOC_FAIL;
600: ctx.keys = keys;
601: ctx.nkeys = nkeys;
1.64 djm 602: ctx.modified = 0;
1.62 djm 603:
604: /*
605: * Prepare temporary file for in-place deletion.
606: */
1.75 deraadt 607: if ((r = asprintf(&temp, "%s.XXXXXXXXXXX", filename)) == -1 ||
1.74 deraadt 608: (r = asprintf(&back, "%s.old", filename)) == -1) {
1.62 djm 609: r = SSH_ERR_ALLOC_FAIL;
610: goto fail;
611: }
612:
613: if ((fd = mkstemp(temp)) == -1) {
614: oerrno = errno;
1.86 djm 615: error_f("mkstemp: %s", strerror(oerrno));
1.62 djm 616: r = SSH_ERR_SYSTEM_ERROR;
617: goto fail;
618: }
619: if ((ctx.out = fdopen(fd, "w")) == NULL) {
620: oerrno = errno;
621: close(fd);
1.86 djm 622: error_f("fdopen: %s", strerror(oerrno));
1.62 djm 623: r = SSH_ERR_SYSTEM_ERROR;
624: goto fail;
625: }
626:
1.85 djm 627: /* Remove stale/mismatching entries for the specified host */
1.64 djm 628: if ((r = hostkeys_foreach(filename, host_delete, &ctx, host, ip,
1.87 djm 629: HKF_WANT_PARSE_KEY, 0)) != 0) {
1.77 djm 630: oerrno = errno;
1.86 djm 631: error_fr(r, "hostkeys_foreach");
1.62 djm 632: goto fail;
633: }
634:
1.85 djm 635: /* Re-add the requested keys */
636: want = HKF_MATCH_HOST | (ip == NULL ? 0 : HKF_MATCH_IP);
1.62 djm 637: for (i = 0; i < nkeys; i++) {
1.85 djm 638: if ((want & ctx.match_keys[i]) == want)
1.62 djm 639: continue;
1.64 djm 640: if ((fp = sshkey_fingerprint(keys[i], hash_alg,
641: SSH_FP_DEFAULT)) == NULL) {
642: r = SSH_ERR_ALLOC_FAIL;
643: goto fail;
644: }
1.85 djm 645: /* write host/ip */
646: what = "";
647: if (ctx.match_keys[i] == 0) {
648: what = "Adding new key";
649: if (!write_host_entry(ctx.out, host, ip,
650: keys[i], store_hash)) {
651: r = SSH_ERR_INTERNAL_ERROR;
652: goto fail;
653: }
654: } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_HOST) {
655: what = "Fixing match (hostname)";
656: if (!write_host_entry(ctx.out, host, NULL,
657: keys[i], store_hash)) {
658: r = SSH_ERR_INTERNAL_ERROR;
659: goto fail;
660: }
661: } else if ((want & ~ctx.match_keys[i]) == HKF_MATCH_IP) {
662: what = "Fixing match (address)";
663: if (!write_host_entry(ctx.out, ip, NULL,
664: keys[i], store_hash)) {
665: r = SSH_ERR_INTERNAL_ERROR;
666: goto fail;
667: }
668: }
669: do_log2(loglevel, "%s%s%s for %s%s%s to %s: %s %s",
670: quiet ? __func__ : "", quiet ? ": " : "", what,
671: host, ip == NULL ? "" : ",", ip == NULL ? "" : ip, filename,
1.64 djm 672: sshkey_ssh_name(keys[i]), fp);
673: free(fp);
674: ctx.modified = 1;
1.33 djm 675: }
1.62 djm 676: fclose(ctx.out);
677: ctx.out = NULL;
1.33 djm 678:
1.64 djm 679: if (ctx.modified) {
680: /* Backup the original file and replace it with the temporary */
681: if (unlink(back) == -1 && errno != ENOENT) {
682: oerrno = errno;
1.86 djm 683: error_f("unlink %.100s: %s", back, strerror(errno));
1.64 djm 684: r = SSH_ERR_SYSTEM_ERROR;
685: goto fail;
686: }
687: if (link(filename, back) == -1) {
688: oerrno = errno;
1.86 djm 689: error_f("link %.100s to %.100s: %s", filename,
690: back, strerror(errno));
1.64 djm 691: r = SSH_ERR_SYSTEM_ERROR;
692: goto fail;
693: }
694: if (rename(temp, filename) == -1) {
695: oerrno = errno;
1.86 djm 696: error_f("rename \"%s\" to \"%s\": %s", temp,
697: filename, strerror(errno));
1.64 djm 698: r = SSH_ERR_SYSTEM_ERROR;
699: goto fail;
700: }
701: } else {
702: /* No changes made; just delete the temporary file */
703: if (unlink(temp) != 0)
1.86 djm 704: error_f("unlink \"%s\": %s", temp, strerror(errno));
1.62 djm 705: }
1.64 djm 706:
1.62 djm 707: /* success */
708: r = 0;
709: fail:
710: if (temp != NULL && r != 0)
711: unlink(temp);
712: free(temp);
713: free(back);
714: if (ctx.out != NULL)
715: fclose(ctx.out);
1.85 djm 716: free(ctx.match_keys);
1.63 djm 717: umask(omask);
1.62 djm 718: if (r == SSH_ERR_SYSTEM_ERROR)
719: errno = oerrno;
720: return r;
1.60 djm 721: }
722:
723: static int
724: match_maybe_hashed(const char *host, const char *names, int *was_hashed)
725: {
726: int hashed = *names == HASH_DELIM;
727: const char *hashed_host;
728: size_t nlen = strlen(names);
729:
730: if (was_hashed != NULL)
731: *was_hashed = hashed;
732: if (hashed) {
733: if ((hashed_host = host_hash(host, names, nlen)) == NULL)
734: return -1;
735: return nlen == strlen(hashed_host) &&
736: strncmp(hashed_host, names, nlen) == 0;
737: }
1.66 djm 738: return match_hostname(host, names) == 1;
1.60 djm 739: }
740:
741: int
1.87 djm 742: hostkeys_foreach_file(const char *path, FILE *f, hostkeys_foreach_fn *callback,
743: void *ctx, const char *host, const char *ip, u_int options, u_int note)
1.60 djm 744: {
1.72 markus 745: char *line = NULL, ktype[128];
1.60 djm 746: u_long linenum = 0;
747: char *cp, *cp2;
748: u_int kbits;
1.64 djm 749: int hashed;
1.60 djm 750: int s, r = 0;
751: struct hostkey_foreach_line lineinfo;
1.72 markus 752: size_t linesize = 0, l;
1.60 djm 753:
754: memset(&lineinfo, 0, sizeof(lineinfo));
1.64 djm 755: if (host == NULL && (options & HKF_WANT_MATCH) != 0)
1.60 djm 756: return SSH_ERR_INVALID_ARGUMENT;
757:
1.72 markus 758: while (getline(&line, &linesize, f) != -1) {
759: linenum++;
1.60 djm 760: line[strcspn(line, "\n")] = '\0';
761:
1.73 djm 762: free(lineinfo.line);
1.60 djm 763: sshkey_free(lineinfo.key);
764: memset(&lineinfo, 0, sizeof(lineinfo));
765: lineinfo.path = path;
766: lineinfo.linenum = linenum;
1.72 markus 767: lineinfo.line = xstrdup(line);
1.64 djm 768: lineinfo.marker = MRK_NONE;
1.60 djm 769: lineinfo.status = HKF_STATUS_OK;
1.64 djm 770: lineinfo.keytype = KEY_UNSPEC;
1.87 djm 771: lineinfo.note = note;
1.60 djm 772:
773: /* Skip any leading whitespace, comments and empty lines. */
774: for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
775: ;
776: if (!*cp || *cp == '#' || *cp == '\n') {
1.64 djm 777: if ((options & HKF_WANT_MATCH) == 0) {
1.60 djm 778: lineinfo.status = HKF_STATUS_COMMENT;
779: if ((r = callback(&lineinfo, ctx)) != 0)
780: break;
781: }
782: continue;
783: }
784:
785: if ((lineinfo.marker = check_markers(&cp)) == MRK_ERROR) {
1.86 djm 786: verbose_f("invalid marker at %s:%lu", path, linenum);
1.64 djm 787: if ((options & HKF_WANT_MATCH) == 0)
1.60 djm 788: goto bad;
789: continue;
790: }
791:
792: /* Find the end of the host name portion. */
793: for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
794: ;
795: lineinfo.hosts = cp;
796: *cp2++ = '\0';
797:
798: /* Check if the host name matches. */
799: if (host != NULL) {
1.64 djm 800: if ((s = match_maybe_hashed(host, lineinfo.hosts,
801: &hashed)) == -1) {
1.86 djm 802: debug2_f("%s:%ld: bad host hash \"%.32s\"",
803: path, linenum, lineinfo.hosts);
1.60 djm 804: goto bad;
805: }
1.64 djm 806: if (s == 1) {
807: lineinfo.status = HKF_STATUS_MATCHED;
808: lineinfo.match |= HKF_MATCH_HOST |
809: (hashed ? HKF_MATCH_HOST_HASHED : 0);
810: }
811: /* Try matching IP address if supplied */
812: if (ip != NULL) {
813: if ((s = match_maybe_hashed(ip, lineinfo.hosts,
814: &hashed)) == -1) {
1.86 djm 815: debug2_f("%s:%ld: bad ip hash "
816: "\"%.32s\"", path, linenum,
817: lineinfo.hosts);
1.64 djm 818: goto bad;
819: }
820: if (s == 1) {
821: lineinfo.status = HKF_STATUS_MATCHED;
822: lineinfo.match |= HKF_MATCH_IP |
823: (hashed ? HKF_MATCH_IP_HASHED : 0);
824: }
825: }
826: /*
827: * Skip this line if host matching requested and
828: * neither host nor address matched.
829: */
830: if ((options & HKF_WANT_MATCH) != 0 &&
831: lineinfo.status != HKF_STATUS_MATCHED)
832: continue;
1.60 djm 833: }
834:
835: /* Got a match. Skip host name and any following whitespace */
836: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
837: ;
838: if (*cp2 == '\0' || *cp2 == '#') {
1.64 djm 839: debug2("%s:%ld: truncated before key type",
840: path, linenum);
1.60 djm 841: goto bad;
842: }
843: lineinfo.rawkey = cp = cp2;
844:
845: if ((options & HKF_WANT_PARSE_KEY) != 0) {
846: /*
847: * Extract the key from the line. This will skip
848: * any leading whitespace. Ignore badly formatted
849: * lines.
850: */
851: if ((lineinfo.key = sshkey_new(KEY_UNSPEC)) == NULL) {
1.86 djm 852: error_f("sshkey_new failed");
1.64 djm 853: r = SSH_ERR_ALLOC_FAIL;
854: break;
1.60 djm 855: }
856: if (!hostfile_read_key(&cp, &kbits, lineinfo.key)) {
857: goto bad;
858: }
1.64 djm 859: lineinfo.keytype = lineinfo.key->type;
860: lineinfo.comment = cp;
861: } else {
862: /* Extract and parse key type */
863: l = strcspn(lineinfo.rawkey, " \t");
864: if (l <= 1 || l >= sizeof(ktype) ||
865: lineinfo.rawkey[l] == '\0')
866: goto bad;
867: memcpy(ktype, lineinfo.rawkey, l);
868: ktype[l] = '\0';
869: lineinfo.keytype = sshkey_type_from_name(ktype);
1.65 djm 870:
1.64 djm 871: /*
1.70 djm 872: * Assume legacy RSA1 if the first component is a short
1.64 djm 873: * decimal number.
874: */
875: if (lineinfo.keytype == KEY_UNSPEC && l < 8 &&
876: strspn(ktype, "0123456789") == l)
1.70 djm 877: goto bad;
1.65 djm 878:
1.64 djm 879: /*
880: * Check that something other than whitespace follows
881: * the key type. This won't catch all corruption, but
882: * it does catch trivial truncation.
883: */
884: cp2 += l; /* Skip past key type */
885: for (; *cp2 == ' ' || *cp2 == '\t'; cp2++)
886: ;
887: if (*cp2 == '\0' || *cp2 == '#') {
888: debug2("%s:%ld: truncated after key type",
889: path, linenum);
890: lineinfo.keytype = KEY_UNSPEC;
891: }
892: if (lineinfo.keytype == KEY_UNSPEC) {
1.60 djm 893: bad:
1.64 djm 894: sshkey_free(lineinfo.key);
895: lineinfo.key = NULL;
1.60 djm 896: lineinfo.status = HKF_STATUS_INVALID;
897: if ((r = callback(&lineinfo, ctx)) != 0)
898: break;
899: continue;
900: }
901: }
902: if ((r = callback(&lineinfo, ctx)) != 0)
903: break;
904: }
905: sshkey_free(lineinfo.key);
1.72 markus 906: free(lineinfo.line);
907: free(line);
1.87 djm 908: return r;
909: }
910:
911: int
912: hostkeys_foreach(const char *path, hostkeys_foreach_fn *callback, void *ctx,
913: const char *host, const char *ip, u_int options, u_int note)
914: {
915: FILE *f;
916: int r, oerrno;
917:
918: if ((f = fopen(path, "r")) == NULL)
919: return SSH_ERR_SYSTEM_ERROR;
920:
921: debug3_f("reading file \"%s\"", path);
922: r = hostkeys_foreach_file(path, f, callback, ctx, host, ip,
923: options, note);
924: oerrno = errno;
1.60 djm 925: fclose(f);
1.87 djm 926: errno = oerrno;
1.60 djm 927: return r;
1.1 deraadt 928: }
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