1/*	$NetBSD: ornd_keys.c,v 1.3 2008/12/28 23:20:03 christos Exp $	*/
2
3#include "des_locl.h"
4#include <sys/time.h>
5#include <sys/types.h>
6
7#include <fcntl.h>
8#include <unistd.h>
9
10#include <sha1.h>
11
12void
13des_set_random_generator_seed(des_cblock *seed)
14{
15
16	des_random_seed(seed);
17}
18
19/*
20 * Generate a sequence of random des keys
21 * using the random block sequence, fixup
22 * parity and skip weak keys.
23 */
24int
25des_new_random_key(des_cblock *key)
26{
27	int urandom;
28
29 again:
30	urandom = open("/dev/urandom", O_RDONLY);
31
32	if (urandom < 0)
33		des_random_key(key);
34	else {
35		if (read(urandom, key,
36		    sizeof(des_cblock)) != sizeof(des_cblock)) {
37			close(urandom);
38			des_random_key(key);
39		} else
40			close(urandom);
41	}
42
43	/* random key must have odd parity and not be weak */
44	des_set_odd_parity(key);
45	if (des_is_weak_key(key))
46		goto again;
47
48	return (0);
49}
50
51/*
52 * des_init_random_number_generator:
53 *
54 * This routine takes a secret key possibly shared by a number of servers
55 * and uses it to generate a random number stream that is not shared by
56 * any of the other servers.  It does this by using the current process id,
57 * host id, and the current time to the nearest second.  The resulting
58 * stream seed is not useful information for cracking the secret key.
59 * Moreover, this routine keeps no copy of the secret key.
60 */
61void
62des_init_random_number_generator(des_cblock *seed)
63{
64	u_int64_t seed_q;
65	des_cblock seed_new;
66	SHA1_CTX sha;
67
68	u_char results[20];
69	char hname[64], accum[512];
70
71	struct timeval when;
72
73	SHA1Init(&sha);
74
75	gethostname(hname, sizeof(hname) - 1);
76	gettimeofday(&when, NULL);
77
78	memcpy(&seed_q, seed, sizeof(seed_q));
79
80	snprintf(accum, sizeof(accum), "%lld%ld%d%s%d%lld",
81	    (long long)when.tv_sec, (long)when.tv_usec, getpid(), hname,
82	    getuid(), (long long)seed_q);
83
84	SHA1Update(&sha, (u_char *) accum, strlen(accum));
85
86	memset(accum, 0, sizeof(accum));
87
88	SHA1Final(results, &sha);
89
90	memcpy(seed_new, results, sizeof(seed_new));
91	des_random_seed(&seed_new);
92
93	memset(seed_new, 0, sizeof(seed_new));
94	memset(results, 0, sizeof(results));
95}
96