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"
36 #include "evconfig-private.h"
40 #include "util-internal.h"
41 #include "evthread-internal.h"
43 #ifdef EVENT__HAVE_ARC4RANDOM
47 evutil_secure_rng_set_urandom_device_file(char *fname)
53 evutil_secure_rng_init(void)
55 /* call arc4random() now to force it to self-initialize */
59 #ifndef EVENT__DISABLE_THREAD_SUPPORT
61 evutil_secure_rng_global_setup_locks_(const int enable_locks)
67 evutil_free_secure_rng_globals_locks(void)
72 ev_arc4random_buf(void *buf, size_t n)
74 #if defined(EVENT__HAVE_ARC4RANDOM_BUF) && !defined(__APPLE__)
75 arc4random_buf(buf, n);
78 unsigned char *b = buf;
80 #if defined(EVENT__HAVE_ARC4RANDOM_BUF)
81 /* OSX 10.7 introducd arc4random_buf, so if you build your program
82 * there, you'll get surprised when older versions of OSX fail to run.
83 * To solve this, we can check whether the function pointer is set,
84 * and fall back otherwise. (OSX does this using some linker
88 void (*tptr)(void *,size_t) =
89 (void (*)(void*,size_t))arc4random_buf;
91 arc4random_buf(buf, n);
96 /* Make sure that we start out with b at a 4-byte alignment; plenty
97 * of CPUs care about this for 32-bit access. */
98 if (n >= 4 && ((ev_uintptr_t)b) & 3) {
99 ev_uint32_t u = arc4random();
100 int n_bytes = 4 - (((ev_uintptr_t)b) & 3);
101 memcpy(b, &u, n_bytes);
106 *(ev_uint32_t*)b = arc4random();
111 ev_uint32_t u = arc4random();
117 #else /* !EVENT__HAVE_ARC4RANDOM { */
119 #ifdef EVENT__ssize_t
120 #define ssize_t EVENT__ssize_t
122 #define ARC4RANDOM_EXPORT static
123 #define ARC4_LOCK_() EVLOCK_LOCK(arc4rand_lock, 0)
124 #define ARC4_UNLOCK_() EVLOCK_UNLOCK(arc4rand_lock, 0)
125 #ifndef EVENT__DISABLE_THREAD_SUPPORT
126 static void *arc4rand_lock;
129 #define ARC4RANDOM_UINT32 ev_uint32_t
130 #define ARC4RANDOM_NOSTIR
131 #define ARC4RANDOM_NORANDOM
132 #define ARC4RANDOM_NOUNIFORM
134 #include "./arc4random.c"
136 #ifndef EVENT__DISABLE_THREAD_SUPPORT
138 evutil_secure_rng_global_setup_locks_(const int enable_locks)
140 EVTHREAD_SETUP_GLOBAL_LOCK(arc4rand_lock, 0);
146 evutil_free_secure_rng_globals_locks(void)
148 #ifndef EVENT__DISABLE_THREAD_SUPPORT
149 if (arc4rand_lock != NULL) {
150 EVTHREAD_FREE_LOCK(arc4rand_lock, 0);
151 arc4rand_lock = NULL;
158 evutil_secure_rng_set_urandom_device_file(char *fname)
160 #ifdef TRY_SEED_URANDOM
162 arc4random_urandom_filename = fname;
169 evutil_secure_rng_init(void)
176 val = arc4_seeded_ok ? 0 : -1;
182 ev_arc4random_buf(void *buf, size_t n)
184 arc4random_buf(buf, n);
187 #endif /* } !EVENT__HAVE_ARC4RANDOM */
190 evutil_secure_rng_get_bytes(void *buf, size_t n)
192 ev_arc4random_buf(buf, n);
196 evutil_secure_rng_add_bytes(const char *buf, size_t n)
201 evutil_free_secure_rng_globals_(void)
203 evutil_free_secure_rng_globals_locks();