| Current Path : /usr/src/crypto/openssh/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/src/crypto/openssh/dh.c |
/* $OpenBSD: dh.c,v 1.48 2009/10/01 11:37:33 grunk Exp $ */
/*
* Copyright (c) 2000 Niels Provos. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
#include <sys/param.h>
#include <openssl/bn.h>
#include <openssl/dh.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "dh.h"
#include "pathnames.h"
#include "log.h"
#include "misc.h"
static int
parse_prime(int linenum, char *line, struct dhgroup *dhg)
{
char *cp, *arg;
char *strsize, *gen, *prime;
const char *errstr = NULL;
long long n;
cp = line;
if ((arg = strdelim(&cp)) == NULL)
return 0;
/* Ignore leading whitespace */
if (*arg == '\0')
arg = strdelim(&cp);
if (!arg || !*arg || *arg == '#')
return 0;
/* time */
if (cp == NULL || *arg == '\0')
goto fail;
arg = strsep(&cp, " "); /* type */
if (cp == NULL || *arg == '\0')
goto fail;
/* Ensure this is a safe prime */
n = strtonum(arg, 0, 5, &errstr);
if (errstr != NULL || n != MODULI_TYPE_SAFE)
goto fail;
arg = strsep(&cp, " "); /* tests */
if (cp == NULL || *arg == '\0')
goto fail;
/* Ensure prime has been tested and is not composite */
n = strtonum(arg, 0, 0x1f, &errstr);
if (errstr != NULL ||
(n & MODULI_TESTS_COMPOSITE) || !(n & ~MODULI_TESTS_COMPOSITE))
goto fail;
arg = strsep(&cp, " "); /* tries */
if (cp == NULL || *arg == '\0')
goto fail;
n = strtonum(arg, 0, 1<<30, &errstr);
if (errstr != NULL || n == 0)
goto fail;
strsize = strsep(&cp, " "); /* size */
if (cp == NULL || *strsize == '\0' ||
(dhg->size = (int)strtonum(strsize, 0, 64*1024, &errstr)) == 0 ||
errstr)
goto fail;
/* The whole group is one bit larger */
dhg->size++;
gen = strsep(&cp, " "); /* gen */
if (cp == NULL || *gen == '\0')
goto fail;
prime = strsep(&cp, " "); /* prime */
if (cp != NULL || *prime == '\0')
goto fail;
if ((dhg->g = BN_new()) == NULL)
fatal("parse_prime: BN_new failed");
if ((dhg->p = BN_new()) == NULL)
fatal("parse_prime: BN_new failed");
if (BN_hex2bn(&dhg->g, gen) == 0)
goto failclean;
if (BN_hex2bn(&dhg->p, prime) == 0)
goto failclean;
if (BN_num_bits(dhg->p) != dhg->size)
goto failclean;
if (BN_is_zero(dhg->g) || BN_is_one(dhg->g))
goto failclean;
return (1);
failclean:
BN_clear_free(dhg->g);
BN_clear_free(dhg->p);
fail:
error("Bad prime description in line %d", linenum);
return (0);
}
DH *
choose_dh(int min, int wantbits, int max)
{
FILE *f;
char line[4096];
int best, bestcount, which;
int linenum;
struct dhgroup dhg;
if ((f = fopen(_PATH_DH_MODULI, "r")) == NULL &&
(f = fopen(_PATH_DH_PRIMES, "r")) == NULL) {
logit("WARNING: %s does not exist, using fixed modulus",
_PATH_DH_MODULI);
return (dh_new_group14());
}
linenum = 0;
best = bestcount = 0;
while (fgets(line, sizeof(line), f)) {
linenum++;
if (!parse_prime(linenum, line, &dhg))
continue;
BN_clear_free(dhg.g);
BN_clear_free(dhg.p);
if (dhg.size > max || dhg.size < min)
continue;
if ((dhg.size > wantbits && dhg.size < best) ||
(dhg.size > best && best < wantbits)) {
best = dhg.size;
bestcount = 0;
}
if (dhg.size == best)
bestcount++;
}
rewind(f);
if (bestcount == 0) {
fclose(f);
logit("WARNING: no suitable primes in %s", _PATH_DH_PRIMES);
return (dh_new_group14());
}
linenum = 0;
which = arc4random_uniform(bestcount);
while (fgets(line, sizeof(line), f)) {
if (!parse_prime(linenum, line, &dhg))
continue;
if ((dhg.size > max || dhg.size < min) ||
dhg.size != best ||
linenum++ != which) {
BN_clear_free(dhg.g);
BN_clear_free(dhg.p);
continue;
}
break;
}
fclose(f);
if (linenum != which+1)
fatal("WARNING: line %d disappeared in %s, giving up",
which, _PATH_DH_PRIMES);
return (dh_new_group(dhg.g, dhg.p));
}
/* diffie-hellman-groupN-sha1 */
int
dh_pub_is_valid(DH *dh, BIGNUM *dh_pub)
{
int i;
int n = BN_num_bits(dh_pub);
int bits_set = 0;
BIGNUM *tmp;
if (dh_pub->neg) {
logit("invalid public DH value: negative");
return 0;
}
if (BN_cmp(dh_pub, BN_value_one()) != 1) { /* pub_exp <= 1 */
logit("invalid public DH value: <= 1");
return 0;
}
if ((tmp = BN_new()) == NULL) {
error("%s: BN_new failed", __func__);
return 0;
}
if (!BN_sub(tmp, dh->p, BN_value_one()) ||
BN_cmp(dh_pub, tmp) != -1) { /* pub_exp > p-2 */
BN_clear_free(tmp);
logit("invalid public DH value: >= p-1");
return 0;
}
BN_clear_free(tmp);
for (i = 0; i <= n; i++)
if (BN_is_bit_set(dh_pub, i))
bits_set++;
debug2("bits set: %d/%d", bits_set, BN_num_bits(dh->p));
/* if g==2 and bits_set==1 then computing log_g(dh_pub) is trivial */
if (bits_set > 1)
return 1;
logit("invalid public DH value (%d/%d)", bits_set, BN_num_bits(dh->p));
return 0;
}
void
dh_gen_key(DH *dh, int need)
{
int i, bits_set, tries = 0;
if (dh->p == NULL)
fatal("dh_gen_key: dh->p == NULL");
if (need > INT_MAX / 2 || 2 * need >= BN_num_bits(dh->p))
fatal("dh_gen_key: group too small: %d (2*need %d)",
BN_num_bits(dh->p), 2*need);
do {
if (dh->priv_key != NULL)
BN_clear_free(dh->priv_key);
if ((dh->priv_key = BN_new()) == NULL)
fatal("dh_gen_key: BN_new failed");
/* generate a 2*need bits random private exponent */
if (!BN_rand(dh->priv_key, 2*need, 0, 0))
fatal("dh_gen_key: BN_rand failed");
if (DH_generate_key(dh) == 0)
fatal("DH_generate_key");
for (i = 0, bits_set = 0; i <= BN_num_bits(dh->priv_key); i++)
if (BN_is_bit_set(dh->priv_key, i))
bits_set++;
debug2("dh_gen_key: priv key bits set: %d/%d",
bits_set, BN_num_bits(dh->priv_key));
if (tries++ > 10)
fatal("dh_gen_key: too many bad keys: giving up");
} while (!dh_pub_is_valid(dh, dh->pub_key));
}
DH *
dh_new_group_asc(const char *gen, const char *modulus)
{
DH *dh;
if ((dh = DH_new()) == NULL)
fatal("dh_new_group_asc: DH_new");
if (BN_hex2bn(&dh->p, modulus) == 0)
fatal("BN_hex2bn p");
if (BN_hex2bn(&dh->g, gen) == 0)
fatal("BN_hex2bn g");
return (dh);
}
/*
* This just returns the group, we still need to generate the exchange
* value.
*/
DH *
dh_new_group(BIGNUM *gen, BIGNUM *modulus)
{
DH *dh;
if ((dh = DH_new()) == NULL)
fatal("dh_new_group: DH_new");
dh->p = modulus;
dh->g = gen;
return (dh);
}
DH *
dh_new_group1(void)
{
static char *gen = "2", *group1 =
"FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
"29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
"EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
"E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
"EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE65381"
"FFFFFFFF" "FFFFFFFF";
return (dh_new_group_asc(gen, group1));
}
DH *
dh_new_group14(void)
{
static char *gen = "2", *group14 =
"FFFFFFFF" "FFFFFFFF" "C90FDAA2" "2168C234" "C4C6628B" "80DC1CD1"
"29024E08" "8A67CC74" "020BBEA6" "3B139B22" "514A0879" "8E3404DD"
"EF9519B3" "CD3A431B" "302B0A6D" "F25F1437" "4FE1356D" "6D51C245"
"E485B576" "625E7EC6" "F44C42E9" "A637ED6B" "0BFF5CB6" "F406B7ED"
"EE386BFB" "5A899FA5" "AE9F2411" "7C4B1FE6" "49286651" "ECE45B3D"
"C2007CB8" "A163BF05" "98DA4836" "1C55D39A" "69163FA8" "FD24CF5F"
"83655D23" "DCA3AD96" "1C62F356" "208552BB" "9ED52907" "7096966D"
"670C354E" "4ABC9804" "F1746C08" "CA18217C" "32905E46" "2E36CE3B"
"E39E772C" "180E8603" "9B2783A2" "EC07A28F" "B5C55DF0" "6F4C52C9"
"DE2BCBF6" "95581718" "3995497C" "EA956AE5" "15D22618" "98FA0510"
"15728E5A" "8AACAA68" "FFFFFFFF" "FFFFFFFF";
return (dh_new_group_asc(gen, group14));
}
/*
* Estimates the group order for a Diffie-Hellman group that has an
* attack complexity approximately the same as O(2**bits). Estimate
* with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3)))
*/
int
dh_estimate(int bits)
{
if (bits <= 128)
return (1024); /* O(2**86) */
if (bits <= 192)
return (2048); /* O(2**116) */
return (4096); /* O(2**156) */
}