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3c0ef626 | 1 | /* |
2 | * Copyright (c) 1999-2000 Damien Miller. All rights reserved. | |
3 | * | |
4 | * Redistribution and use in source and binary forms, with or without | |
5 | * modification, are permitted provided that the following conditions | |
6 | * are met: | |
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. | |
12 | * | |
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. | |
23 | */ | |
24 | ||
25 | #include "includes.h" | |
26 | #include "log.h" | |
27 | ||
28 | RCSID("$Id$"); | |
29 | ||
30 | #ifndef HAVE_ARC4RANDOM | |
31 | ||
32 | #include <openssl/rand.h> | |
33 | #include <openssl/rc4.h> | |
34 | #include <openssl/err.h> | |
35 | ||
36 | /* Size of key to use */ | |
37 | #define SEED_SIZE 20 | |
38 | ||
39 | /* Number of bytes to reseed after */ | |
40 | #define REKEY_BYTES (1 << 24) | |
41 | ||
42 | static int rc4_ready = 0; | |
43 | static RC4_KEY rc4; | |
44 | ||
45 | unsigned int arc4random(void) | |
46 | { | |
47 | unsigned int r = 0; | |
48 | static int first_time = 1; | |
49 | ||
50 | if (rc4_ready <= 0) { | |
51 | if (!first_time) | |
52 | seed_rng(); | |
53 | first_time = 0; | |
54 | arc4random_stir(); | |
55 | } | |
56 | ||
57 | RC4(&rc4, sizeof(r), (unsigned char *)&r, (unsigned char *)&r); | |
58 | ||
59 | rc4_ready -= sizeof(r); | |
60 | ||
61 | return(r); | |
62 | } | |
63 | ||
64 | void arc4random_stir(void) | |
65 | { | |
66 | unsigned char rand_buf[SEED_SIZE]; | |
67 | ||
68 | memset(&rc4, 0, sizeof(rc4)); | |
69 | if (!RAND_bytes(rand_buf, sizeof(rand_buf))) | |
70 | fatal("Couldn't obtain random bytes (error %ld)", | |
71 | ERR_get_error()); | |
72 | RC4_set_key(&rc4, sizeof(rand_buf), rand_buf); | |
73 | memset(rand_buf, 0, sizeof(rand_buf)); | |
74 | ||
75 | rc4_ready = REKEY_BYTES; | |
76 | } | |
77 | #endif /* !HAVE_ARC4RANDOM */ |