external/bsd/libevent/dist/evutil_rand.c

   1 /*      $NetBSD: evutil_rand.c,v 1.4 2015/02/01 10:19:00 njoly Exp $    */
   2 /*
   3  * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 /* This file has our secure PRNG code.  On platforms that have arc4random(),
  29  * we just use that.  Otherwise, we include arc4random.c as a bunch of static
  30  * functions, and wrap it lightly.  We don't expose the arc4random*() APIs
  31  * because A) they aren't in our namespace, and B) it's not nice to name your
  32  * APIs after their implementations.  We keep them in a separate file
  33  * so that other people can rip it out and use it for whatever.
  34  */
  35
  36 #include "event2/event-config.h"
  37 #include <sys/cdefs.h>
  38 __RCSID("$NetBSD: evutil_rand.c,v 1.4 2015/02/01 10:19:00 njoly Exp $");
  39
  40 #include <limits.h>
  41
  42 #include "util-internal.h"
  43 #include "evthread-internal.h"
  44
  45 #ifdef _EVENT_HAVE_ARC4RANDOM
  46 #include <stdlib.h>
  47 #include <string.h>
  48 int
  49 evutil_secure_rng_set_urandom_device_file(char *fname)
  50 {
  51         (void) fname;
  52         return -1;
  53 }
  54 int
  55 evutil_secure_rng_init(void)
  56 {
  57         /* call arc4random() now to force it to self-initialize */
  58         (void) arc4random();
  59         return 0;
  60 }
  61 #if defined(__minix) && !defined(_EVENT_DISABLE_THREAD_SUPPORT)
  62 int
  63 /*ARGSUSED*/
  64 evutil_secure_rng_global_setup_locks_(const int enable_locks)
  65 {
  66         return 0;
  67 }
  68 #endif /* defined(__minix) && !defined(_EVENT_DISABLE_THREAD_SUPPORT) */
  69
  70 static void
  71 /*ARGSUSED*/
  72 ev_arc4random_buf(void *buf, size_t n)
  73 {
  74 #if defined(_EVENT_HAVE_ARC4RANDOM_BUF) && !defined(__APPLE__)
  75         arc4random_buf(buf, n);
  76         return;
  77 #else
  78         unsigned char *b = buf;
  79
  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
  85          * trickery.)
  86          */
  87         {
  88                 void (*tptr)(void *,size_t) =
  89                     (void (*)(void*,size_t))arc4random_buf;
  90                 if (tptr != NULL) {
  91                         arc4random_buf(buf, n);
  92                         return;
  93                 }
  94         }
  95 #endif
  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);
 102                 b += n_bytes;
 103                 n -= n_bytes;
 104         }
 105         while (n >= 4) {
 106                 *(ev_uint32_t*)b = arc4random();
 107                 b += 4;
 108                 n -= 4;
 109         }
 110         if (n) {
 111                 ev_uint32_t u = arc4random();
 112                 memcpy(b, &u, n);
 113         }
 114 #endif
 115 }
 116
 117 #else /* !_EVENT_HAVE_ARC4RANDOM { */
 118
 119 #ifdef _EVENT_ssize_t
 120 #define ssize_t _EVENT_SSIZE_t
 121 #endif
 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;
 127 #endif
 128
 129 #define ARC4RANDOM_UINT32 ev_uint32_t
 130 #define ARC4RANDOM_NOSTIR
 131 #define ARC4RANDOM_NORANDOM
 132 #define ARC4RANDOM_NOUNIFORM
 133
 134 #include "./arc4random.c"
 135
 136 #ifndef _EVENT_DISABLE_THREAD_SUPPORT
 137 int
 138 evutil_secure_rng_global_setup_locks_(const int enable_locks)
 139 {
 140         EVTHREAD_SETUP_GLOBAL_LOCK(arc4rand_lock, 0);
 141         return 0;
 142 }
 143 #endif
 144
 145 int
 146 /*ARGSUSED*/
 147 evutil_secure_rng_set_urandom_device_file(char *fname)
 148 {
 149 #ifdef TRY_SEED_URANDOM
 150         _ARC4_LOCK();
 151         arc4random_urandom_filename = fname;
 152         _ARC4_UNLOCK();
 153 #endif
 154         return 0;
 155 }
 156
 157 int
 158 evutil_secure_rng_init(void)
 159 {
 160         int val;
 161
 162         _ARC4_LOCK();
 163         if (!arc4_seeded_ok)
 164                 arc4_stir();
 165         val = arc4_seeded_ok ? 0 : -1;
 166         _ARC4_UNLOCK();
 167         return val;
 168 }
 169
 170 static void
 171 ev_arc4random_buf(void *buf, size_t n)
 172 {
 173         arc4random_buf(buf, n);
 174 }
 175
 176 #endif /* } !_EVENT_HAVE_ARC4RANDOM */
 177
 178 void
 179 evutil_secure_rng_get_bytes(void *buf, size_t n)
 180 {
 181         ev_arc4random_buf(buf, n);
 182 }
 183
 184 void
 185 evutil_secure_rng_add_bytes(const char *buf, size_t n)
 186 {
 187         arc4random_addrandom(__UNCONST(buf),
 188             n>(size_t)INT_MAX ? INT_MAX : (int)n);
 189 }
 190