2 * Copyright (c) 2000 Niels Provos. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 RCSID("$OpenBSD: dh.c,v 1.10 2001/03/28 22:04:57 provos Exp $");
30 #include <openssl/bn.h>
31 #include <openssl/dh.h>
32 #include <openssl/evp.h>
38 #include "pathnames.h"
43 parse_prime(int linenum, char *line, struct dhgroup *dhg)
46 char *strsize, *gen, *prime;
50 /* Ignore leading whitespace */
53 if (!*arg || *arg == '#')
57 if (cp == NULL || *arg == '\0')
59 arg = strsep(&cp, " "); /* type */
60 if (cp == NULL || *arg == '\0')
62 arg = strsep(&cp, " "); /* tests */
63 if (cp == NULL || *arg == '\0')
65 arg = strsep(&cp, " "); /* tries */
66 if (cp == NULL || *arg == '\0')
68 strsize = strsep(&cp, " "); /* size */
69 if (cp == NULL || *strsize == '\0' ||
70 (dhg->size = atoi(strsize)) == 0)
72 /* The whole group is one bit larger */
74 gen = strsep(&cp, " "); /* gen */
75 if (cp == NULL || *gen == '\0')
77 prime = strsep(&cp, " "); /* prime */
78 if (cp != NULL || *prime == '\0')
83 if (BN_hex2bn(&dhg->g, gen) < 0)
86 if (BN_hex2bn(&dhg->p, prime) < 0)
89 if (BN_num_bits(dhg->p) != dhg->size)
98 error("Bad prime description in line %d", linenum);
103 choose_dh(int min, int wantbits, int max)
107 int best, bestcount, which;
111 f = fopen(_PATH_DH_PRIMES, "r");
113 log("WARNING: %s does not exist, using old prime", _PATH_DH_PRIMES);
114 return (dh_new_group1());
118 best = bestcount = 0;
119 while (fgets(line, sizeof(line), f)) {
121 if (!parse_prime(linenum, line, &dhg))
126 if (dhg.size > max || dhg.size < min)
129 if ((dhg.size > wantbits && dhg.size < best) ||
130 (dhg.size > best && best < wantbits)) {
134 if (dhg.size == best)
139 if (bestcount == 0) {
140 log("WARNING: no suitable primes in %s", _PATH_DH_PRIMES);
144 f = fopen(_PATH_DH_PRIMES, "r");
146 fatal("WARNING: %s disappeared, giving up", _PATH_DH_PRIMES);
150 which = arc4random() % bestcount;
151 while (fgets(line, sizeof(line), f)) {
152 if (!parse_prime(linenum, line, &dhg))
154 if (dhg.size > max || dhg.size < min)
156 if (dhg.size != best)
158 if (linenum++ != which) {
167 return (dh_new_group(dhg.g, dhg.p));