2 * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
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 * 3. The name of the author may not be used to endorse or promote products
13 * derived from this software without specific prior written permission.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 /* This file has our secure PRNG code. On platforms that have arc4random(),
28 * we just use that. Otherwise, we include arc4random.c as a bunch of static
29 * functions, and wrap it lightly. We don't expose the arc4random*() APIs
30 * because A) they aren't in our namespace, and B) it's not nice to name your
31 * APIs after their implementations. We keep them in a separate file
32 * so that other people can rip it out and use it for whatever.
35 #include "event2/event-config.h"
39 #include "util-internal.h"
40 #include "evthread-internal.h"
42 #ifdef _EVENT_HAVE_ARC4RANDOM
46 evutil_secure_rng_init(void)
48 /* call arc4random() now to force it to self-initialize */
53 evutil_secure_rng_global_setup_locks_(const int enable_locks
)
59 ev_arc4random_buf(void *buf
, size_t n
)
61 #if defined(_EVENT_HAVE_ARC4RANDOM_BUF) && !defined(__APPLE__)
62 arc4random_buf(buf
, n
);
65 unsigned char *b
= buf
;
67 #if defined(_EVENT_HAVE_ARC4RANDOM_BUF)
68 /* OSX 10.7 introducd arc4random_buf, so if you build your program
69 * there, you'll get surprised when older versions of OSX fail to run.
70 * To solve this, we can check whether the function pointer is set,
71 * and fall back otherwise. (OSX does this using some linker
74 if (arc4random_buf
!= NULL
) {
75 arc4random_buf(buf
, n
);
79 /* Make sure that we start out with b at a 4-byte alignment; plenty
80 * of CPUs care about this for 32-bit access. */
81 if (n
>= 4 && ((ev_uintptr_t
)b
) & 3) {
82 ev_uint32_t u
= arc4random();
83 int n_bytes
= 4 - (((ev_uintptr_t
)b
) & 3);
84 memcpy(b
, &u
, n_bytes
);
89 *(ev_uint32_t
*)b
= arc4random();
94 ev_uint32_t u
= arc4random();
100 #else /* !_EVENT_HAVE_ARC4RANDOM { */
102 #ifdef _EVENT_ssize_t
103 #define ssize_t _EVENT_SSIZE_t
105 #define ARC4RANDOM_EXPORT static
106 #define _ARC4_LOCK() EVLOCK_LOCK(arc4rand_lock, 0)
107 #define _ARC4_UNLOCK() EVLOCK_UNLOCK(arc4rand_lock, 0)
108 #ifndef _EVENT_DISABLE_THREAD_SUPPORT
109 static void *arc4rand_lock
;
112 #define ARC4RANDOM_UINT32 ev_uint32_t
113 #define ARC4RANDOM_NOSTIR
114 #define ARC4RANDOM_NORANDOM
115 #define ARC4RANDOM_NOUNIFORM
117 #include "./arc4random.c"
119 #ifndef _EVENT_DISABLE_THREAD_SUPPORT
121 evutil_secure_rng_global_setup_locks_(const int enable_locks
)
123 EVTHREAD_SETUP_GLOBAL_LOCK(arc4rand_lock
, 0);
129 evutil_secure_rng_init(void)
136 val
= arc4_seeded_ok
? 0 : -1;
142 ev_arc4random_buf(void *buf
, size_t n
)
144 arc4random_buf(buf
, n
);
147 #endif /* } !_EVENT_HAVE_ARC4RANDOM */
150 evutil_secure_rng_get_bytes(void *buf
, size_t n
)
152 ev_arc4random_buf(buf
, n
);
156 evutil_secure_rng_add_bytes(const char *buf
, size_t n
)
158 arc4random_addrandom((unsigned char*)buf
,
159 n
>(size_t)INT_MAX
? INT_MAX
: (int)n
);