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comparison pws-random.c @ 0:d541e748cfd8

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Initial revision
author Guido Berhoerster <guido+libpws@berhoerster.name>
date Tue, 10 Feb 2015 11:29:54 +0100
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-1:000000000000 0:d541e748cfd8
1 /*
2 * Copyright (C) 2015 Guido Berhoerster <guido+libpws@berhoerster.name>
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files (the
6 * "Software"), to deal in the Software without restriction, including
7 * without limitation the rights to use, copy, modify, merge, publish,
8 * distribute, sublicense, and/or sell copies of the Software, and to
9 * permit persons to whom the Software is furnished to do so, subject to
10 * the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included
13 * in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 */
23
24 #include "compat.h"
25 #include "pws-internal.h"
26
27 #ifdef HAVE_ARC4RANDOM
28 /* prefer system arc4random(3) implementation */
29 #include <stdlib.h>
30 #else /* HAVE_ARC4RANDOM */
31 #ifdef HAVE_GETENTROPY
32 /*
33 * otherwise use system getentropy(2) implementation or fallback to seed
34 * Yarrow-256 PRNG from libnettle
35 */
36 #include <unistd.h>
37 #endif /* HAVE_GETENTROPY */
38 #include <nettle/yarrow.h>
39 #endif /* HAVE_ARC4RANDOM */
40
41 #include "pws-internal.h"
42
43 int
44 pws_random_bytes(void *buf, size_t buf_size)
45 {
46 #ifdef HAVE_ARC4RANDOM
47 arc4random_buf(buf, buf_size);
48 #else /* HAVE_ARC4RANDOM */
49 struct yarrow256_ctx ctx;
50 unsigned char seed_buf[YARROW256_SEED_FILE_SIZE];
51
52 if (getentropy(&seed_buf, sizeof (seed_buf)) != 0) {
53 return (-1);
54 }
55 yarrow256_init(&ctx, 0, NULL);
56 yarrow256_seed(&ctx, sizeof (seed_buf), seed_buf);
57 yarrow256_random(&ctx, buf_size, buf);
58 #endif /* HAVE_ARC4RANDOM */
59
60 return (0);
61 }