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 1.32 2003/11/10 16:23:41 jakob Exp $");
48 * Parses an RSA (number of bits, e, n) or DSA key from a string. Moves the
49 * pointer over the key. Skips any whitespace at the beginning and at end.
53 hostfile_read_key(char **cpp
, u_int
*bitsp
, Key
*ret
)
57 /* Skip leading whitespace. */
58 for (cp
= *cpp
; *cp
== ' ' || *cp
== '\t'; cp
++)
61 if (key_read(ret
, &cp
) != 1)
64 /* Skip trailing whitespace. */
65 for (; *cp
== ' ' || *cp
== '\t'; cp
++)
70 *bitsp
= key_size(ret
);
75 hostfile_check_key(int bits
, const Key
*key
, const char *host
, const char *filename
, int linenum
)
77 if (key
== NULL
|| key
->type
!= KEY_RSA1
|| key
->rsa
== NULL
)
79 if (bits
!= BN_num_bits(key
->rsa
->n
)) {
80 logit("Warning: %s, line %d: keysize mismatch for host %s: "
81 "actual %d vs. announced %d.",
82 filename
, linenum
, host
, BN_num_bits(key
->rsa
->n
), bits
);
83 logit("Warning: replace %d with %d in %s, line %d.",
84 bits
, BN_num_bits(key
->rsa
->n
), filename
, linenum
);
90 * Checks whether the given host (which must be in all lowercase) is already
91 * in the list of our known hosts. Returns HOST_OK if the host is known and
92 * has the specified key, HOST_NEW if the host is not known, and HOST_CHANGED
93 * if the host is known but used to have a different host key.
95 * If no 'key' has been specified and a key of type 'keytype' is known
96 * for the specified host, then HOST_FOUND is returned.
100 check_host_in_hostfile_by_key_or_type(const char *filename
,
101 const char *host
, const Key
*key
, int keytype
, Key
*found
, int *numret
)
108 HostStatus end_return
;
110 debug3("check_host_in_hostfile: filename %s", filename
);
112 /* Open the file containing the list of known hosts. */
113 f
= fopen(filename
, "r");
118 * Return value when the loop terminates. This is set to
119 * HOST_CHANGED if we have seen a different key for the host and have
120 * not found the proper one.
122 end_return
= HOST_NEW
;
124 /* Go through the file. */
125 while (fgets(line
, sizeof(line
), f
)) {
129 /* Skip any leading whitespace, comments and empty lines. */
130 for (; *cp
== ' ' || *cp
== '\t'; cp
++)
132 if (!*cp
|| *cp
== '#' || *cp
== '\n')
135 /* Find the end of the host name portion. */
136 for (cp2
= cp
; *cp2
&& *cp2
!= ' ' && *cp2
!= '\t'; cp2
++)
139 /* Check if the host name matches. */
140 if (match_hostname(host
, cp
, (u_int
) (cp2
- cp
)) != 1)
143 /* Got a match. Skip host name. */
147 * Extract the key from the line. This will skip any leading
148 * whitespace. Ignore badly formatted lines.
150 if (!hostfile_read_key(&cp
, &kbits
, found
))
157 /* we found a key of the requested type */
158 if (found
->type
== keytype
)
163 if (!hostfile_check_key(kbits
, found
, host
, filename
, linenum
))
166 /* Check if the current key is the same as the given key. */
167 if (key_equal(key
, found
)) {
168 /* Ok, they match. */
169 debug3("check_host_in_hostfile: match line %d", linenum
);
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 check_host_in_hostfile(const char *filename
, const char *host
, const Key
*key
,
192 Key
*found
, int *numret
)
195 fatal("no key to look up");
196 return (check_host_in_hostfile_by_key_or_type(filename
, host
, key
, 0,
201 lookup_key_in_hostfile_by_type(const char *filename
, const char *host
,
202 int keytype
, Key
*found
, int *numret
)
204 return (check_host_in_hostfile_by_key_or_type(filename
, host
, NULL
,
205 keytype
, found
, numret
) == HOST_FOUND
);
209 * Appends an entry to the host file. Returns false if the entry could not
214 add_host_to_hostfile(const char *filename
, const char *host
, const Key
*key
)
219 return 1; /* XXX ? */
220 f
= fopen(filename
, "a");
223 fprintf(f
, "%s ", host
);
224 if (key_write(key
, f
)) {
227 error("add_host_to_hostfile: saving key in %s failed", filename
);