2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * Functions for manipulating the known hosts files.
7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
14 * Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
15 * Copyright (c) 1999 Niels Provos. All rights reserved.
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 RCSID("$OpenBSD: hostfile.c,v 1.21 2000/11/12 19:50:37 markus Exp $");
44 #include <openssl/rsa.h>
45 #include <openssl/dsa.h>
50 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the
51 * pointer over the key. Skips any whitespace at the beginning and at end.
55 hostfile_read_key(char **cpp, unsigned int *bitsp, Key *ret)
59 /* Skip leading whitespace. */
60 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
63 if (key_read(ret, &cp) != 1)
66 /* Skip trailing whitespace. */
67 for (; *cp == ' ' || *cp == '\t'; cp++)
72 *bitsp = key_size(ret);
77 auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n)
79 Key *k = key_new(KEY_RSA1);
80 int ret = hostfile_read_key(cpp, bitsp, k);
81 BN_copy(e, k->rsa->e);
82 BN_copy(n, k->rsa->n);
88 hostfile_check_key(int bits, Key *key, const char *host, const char *filename, int linenum)
90 if (key == NULL || key->type != KEY_RSA1 || key->rsa == NULL)
92 if (bits != BN_num_bits(key->rsa->n)) {
93 log("Warning: %s, line %d: keysize mismatch for host %s: "
94 "actual %d vs. announced %d.",
95 filename, linenum, host, BN_num_bits(key->rsa->n), bits);
96 log("Warning: replace %d with %d in %s, line %d.",
97 bits, BN_num_bits(key->rsa->n), filename, linenum);
103 * Checks whether the given host (which must be in all lowercase) is already
104 * in the list of our known hosts. Returns HOST_OK if the host is known and
105 * has the specified key, HOST_NEW if the host is not known, and HOST_CHANGED
106 * if the host is known but used to have a different host key.
110 check_host_in_hostfile(const char *filename, const char *host, Key *key, Key *found)
115 unsigned int kbits, hostlen;
117 HostStatus end_return;
120 fatal("no key to look up");
121 /* Open the file containing the list of known hosts. */
122 f = fopen(filename, "r");
126 /* Cache the length of the host name. */
127 hostlen = strlen(host);
130 * Return value when the loop terminates. This is set to
131 * HOST_CHANGED if we have seen a different key for the host and have
132 * not found the proper one.
134 end_return = HOST_NEW;
136 /* Go trough the file. */
137 while (fgets(line, sizeof(line), f)) {
141 /* Skip any leading whitespace, comments and empty lines. */
142 for (; *cp == ' ' || *cp == '\t'; cp++)
144 if (!*cp || *cp == '#' || *cp == '\n')
147 /* Find the end of the host name portion. */
148 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
151 /* Check if the host name matches. */
152 if (match_hostname(host, cp, (unsigned int) (cp2 - cp)) != 1)
155 /* Got a match. Skip host name. */
159 * Extract the key from the line. This will skip any leading
160 * whitespace. Ignore badly formatted lines.
162 if (!hostfile_read_key(&cp, &kbits, found))
164 if (!hostfile_check_key(kbits, found, host, filename, linenum))
167 /* Check if the current key is the same as the given key. */
168 if (key_equal(key, found)) {
169 /* Ok, they match. */
174 * They do not match. We will continue to go through the
175 * file; however, we note that we will not return that it is
178 end_return = HOST_CHANGED;
180 /* Clear variables and close the file. */
184 * Return either HOST_NEW or HOST_CHANGED, depending on whether we
185 * saw a different key for the host.
191 * Appends an entry to the host file. Returns false if the entry could not
196 add_host_to_hostfile(const char *filename, const char *host, Key *key)
201 return 1; /* XXX ? */
202 f = fopen(filename, "a");
205 fprintf(f, "%s ", host);
206 if (key_write(key, f)) {
209 error("add_host_to_hostfile: saving key in %s failed", filename);