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 1.4 2001/01/15 21:43:51 markus Exp $");
30 #include <openssl/bn.h>
31 #include <openssl/dh.h>
32 #include <openssl/evp.h>
40 parse_prime(int linenum, char *line, struct dhgroup *dhg)
43 char *strsize, *gen, *prime;
47 /* Ignore leading whitespace */
50 if (!*arg || *arg == '#')
54 if (cp == NULL || *arg == '\0')
56 arg = strsep(&cp, " "); /* type */
57 if (cp == NULL || *arg == '\0')
59 arg = strsep(&cp, " "); /* tests */
60 if (cp == NULL || *arg == '\0')
62 arg = strsep(&cp, " "); /* tries */
63 if (cp == NULL || *arg == '\0')
65 strsize = strsep(&cp, " "); /* size */
66 if (cp == NULL || *strsize == '\0' ||
67 (dhg->size = atoi(strsize)) == 0)
69 gen = strsep(&cp, " "); /* gen */
70 if (cp == NULL || *gen == '\0')
72 prime = strsep(&cp, " "); /* prime */
73 if (cp != NULL || *prime == '\0')
77 if (BN_hex2bn(&dhg->g, gen) < 0) {
82 if (BN_hex2bn(&dhg->p, prime) < 0) {
90 error("Bad prime description in line %d\n", linenum);
95 choose_dh(int minbits)
99 int best, bestcount, which;
103 f = fopen(DH_PRIMES, "r");
105 log("WARNING: %s does not exist, using old prime", DH_PRIMES);
106 return (dh_new_group1());
110 best = bestcount = 0;
111 while (fgets(line, sizeof(line), f)) {
113 if (!parse_prime(linenum, line, &dhg))
118 if ((dhg.size > minbits && dhg.size < best) ||
119 (dhg.size > best && best < minbits)) {
123 if (dhg.size == best)
128 if (bestcount == 0) {
129 log("WARNING: no primes in %s, using old prime", DH_PRIMES);
130 return (dh_new_group1());
133 f = fopen(DH_PRIMES, "r");
135 fatal("WARNING: %s dissappeared, giving up", DH_PRIMES);
139 which = arc4random() % bestcount;
140 while (fgets(line, sizeof(line), f)) {
141 if (!parse_prime(linenum, line, &dhg))
143 if (dhg.size != best)
145 if (linenum++ != which) {
154 return (dh_new_group(dhg.g, dhg.p));