NetBSD/lib/libdes/ornd_keys.c

96 lines
2.0 KiB
C

/* $NetBSD: ornd_keys.c,v 1.2 2005/12/13 12:59:48 martin Exp $ */
#include "des_locl.h"
#include <sys/time.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <sha1.h>
void
des_set_random_generator_seed(des_cblock *seed)
{
des_random_seed(seed);
}
/*
* Generate a sequence of random des keys
* using the random block sequence, fixup
* parity and skip weak keys.
*/
int
des_new_random_key(des_cblock *key)
{
int urandom;
again:
urandom = open("/dev/urandom", O_RDONLY);
if (urandom < 0)
des_random_key(key);
else {
if (read(urandom, key,
sizeof(des_cblock)) != sizeof(des_cblock)) {
close(urandom);
des_random_key(key);
} else
close(urandom);
}
/* random key must have odd parity and not be weak */
des_set_odd_parity(key);
if (des_is_weak_key(key))
goto again;
return (0);
}
/*
* des_init_random_number_generator:
*
* This routine takes a secret key possibly shared by a number of servers
* and uses it to generate a random number stream that is not shared by
* any of the other servers. It does this by using the current process id,
* host id, and the current time to the nearest second. The resulting
* stream seed is not useful information for cracking the secret key.
* Moreover, this routine keeps no copy of the secret key.
*/
void
des_init_random_number_generator(des_cblock *seed)
{
u_int64_t seed_q;
des_cblock seed_new;
SHA1_CTX sha;
u_char results[20];
char hname[64], accum[512];
struct timeval when;
SHA1Init(&sha);
gethostname(hname, sizeof(hname) - 1);
gettimeofday(&when, NULL);
memcpy(&seed_q, seed, sizeof(seed_q));
snprintf(accum, sizeof(accum), "%ld%ld%d%s%d%lld",
when.tv_sec, when.tv_usec, getpid(), hname, getuid(),
(long long) seed_q);
SHA1Update(&sha, (u_char *) accum, strlen(accum));
memset(accum, 0, sizeof(accum));
SHA1Final(results, &sha);
memcpy(seed_new, results, sizeof(seed_new));
des_random_seed(&seed_new);
memset(seed_new, 0, sizeof(seed_new));
memset(results, 0, sizeof(results));
}