5 * Author: Tatu Ylonen <ylo@cs.hut.fi>
7 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
10 * Created: Thu Jun 29 07:10:56 1995 ylo
12 * Functions for manipulating the known hosts files.
17 RCSID("$OpenBSD: hostfile.c,v 1.16 2000/04/14 10:30:31 markus Exp $");
22 #include <openssl/rsa.h>
23 #include <openssl/dsa.h>
28 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the
29 * pointer over the key. Skips any whitespace at the beginning and at end.
33 hostfile_read_key(char **cpp, unsigned int *bitsp, Key *ret)
38 /* Skip leading whitespace. */
39 for (cp = *cpp; *cp == ' ' || *cp == '\t'; cp++)
42 /* Get number of bits. */
43 if (*cp < '0' || *cp > '9')
44 return 0; /* Bad bit count... */
45 for (bits = 0; *cp >= '0' && *cp <= '9'; cp++)
46 bits = 10 * bits + *cp - '0';
48 if (!key_read(ret, bits, &cp))
51 /* Skip trailing whitespace. */
52 for (; *cp == ' ' || *cp == '\t'; cp++)
62 auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n)
64 Key *k = key_new(KEY_RSA);
65 int ret = hostfile_read_key(cpp, bitsp, k);
66 BN_copy(e, k->rsa->e);
67 BN_copy(n, k->rsa->n);
73 hostfile_check_key(int bits, Key *key, const char *host, const char *filename, int linenum)
75 if (key == NULL || key->type != KEY_RSA || key->rsa == NULL)
77 if (bits != BN_num_bits(key->rsa->n)) {
78 error("Warning: %s, line %d: keysize mismatch for host %s: "
79 "actual %d vs. announced %d.",
80 filename, linenum, host, BN_num_bits(key->rsa->n), bits);
81 error("Warning: replace %d with %d in %s, line %d.",
82 bits, BN_num_bits(key->rsa->n), filename, linenum);
88 * Checks whether the given host (which must be in all lowercase) is already
89 * in the list of our known hosts. Returns HOST_OK if the host is known and
90 * has the specified key, HOST_NEW if the host is not known, and HOST_CHANGED
91 * if the host is known but used to have a different host key.
95 check_host_in_hostfile(const char *filename, const char *host, Key *key, Key *found)
100 unsigned int kbits, hostlen;
102 HostStatus end_return;
105 fatal("no key to look up");
106 /* Open the file containing the list of known hosts. */
107 f = fopen(filename, "r");
111 /* Cache the length of the host name. */
112 hostlen = strlen(host);
115 * Return value when the loop terminates. This is set to
116 * HOST_CHANGED if we have seen a different key for the host and have
117 * not found the proper one.
119 end_return = HOST_NEW;
121 /* Go trough the file. */
122 while (fgets(line, sizeof(line), f)) {
126 /* Skip any leading whitespace, comments and empty lines. */
127 for (; *cp == ' ' || *cp == '\t'; cp++)
129 if (!*cp || *cp == '#' || *cp == '\n')
132 /* Find the end of the host name portion. */
133 for (cp2 = cp; *cp2 && *cp2 != ' ' && *cp2 != '\t'; cp2++)
136 /* Check if the host name matches. */
137 if (!match_hostname(host, cp, (unsigned int) (cp2 - cp)))
140 /* Got a match. Skip host name. */
144 * Extract the key from the line. This will skip any leading
145 * whitespace. Ignore badly formatted lines.
147 if (!hostfile_read_key(&cp, &kbits, found))
149 if (!hostfile_check_key(kbits, found, host, filename, linenum))
152 /* Check if the current key is the same as the given key. */
153 if (key_equal(key, found)) {
154 /* Ok, they match. */
159 * They do not match. We will continue to go through the
160 * file; however, we note that we will not return that it is
163 end_return = HOST_CHANGED;
165 /* Clear variables and close the file. */
169 * Return either HOST_NEW or HOST_CHANGED, depending on whether we
170 * saw a different key for the host.
176 * Appends an entry to the host file. Returns false if the entry could not
181 add_host_to_hostfile(const char *filename, const char *host, Key *key)
189 /* Open the file for appending. */
190 f = fopen(filename, "a");
194 fprintf(f, "%s ", host);
195 if (key_write(key, f)) {
199 error("add_host_to_hostfile: saving key failed");
202 /* Close the file. */