1 /* $NetBSD: rnd_keys.c,v 1.2 2014/03/27 16:26:22 apb 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
12 void
des_set_random_generator_seed(des_cblock * seed)13 des_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 */
24 int
des_new_random_key(des_cblock * key)25 des_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 */
61 void
des_init_random_number_generator(des_cblock * seed)62 des_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), "%ld%ld%d%s%d%lld",
81 when.tv_sec, when.tv_usec, getpid(), hname, getuid(),
82 (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