/*
* Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* This file has our secure PRNG code. On platforms that have arc4random(),
* we just use that. Otherwise, we include arc4random.c as a bunch of static
* functions, and wrap it lightly. We don't expose the arc4random*() APIs
* because A) they aren't in our namespace, and B) it's not nice to name your
* APIs after their implementations. We keep them in a separate file
* so that other people can rip it out and use it for whatever.
*/
#include "event2/event-config.h"
#include "evconfig-private.h"
#include <limits.h>
#include "util-internal.h"
#include "evthread-internal.h"
#ifdef EVENT__HAVE_ARC4RANDOM
#include <stdlib.h>
#include <string.h>
int
evutil_secure_rng_set_urandom_device_file(char *fname)
{
(void) fname;
return -1;
}
int
evutil_secure_rng_init(void)
{
/* call arc4random() now to force it to self-initialize */
(void)! arc4random();
return 0;
}
#ifndef EVENT__DISABLE_THREAD_SUPPORT
int
evutil_secure_rng_global_setup_locks_(const int enable_locks)
{
return 0;
}
#endif
static void
evutil_free_secure_rng_globals_locks(void)
{
}
static void
ev_arc4random_buf(void *buf, size_t n)
{
#if defined(EVENT__HAVE_ARC4RANDOM_BUF) && !defined(__APPLE__)
arc4random_buf(buf, n);
return;
#else
unsigned char *b = buf;
#if defined(EVENT__HAVE_ARC4RANDOM_BUF)
/* OSX 10.7 introduced arc4random_buf, so if you build your program
* there, you'll get surprised when older versions of OSX fail to run.
* To solve this, we can check whether the function pointer is set,
* and fall back otherwise. (OSX does this using some linker
* trickery.)
*/
{
void (*tptr)(void *,size_t) =
(void (*)(void*,size_t))arc4random_buf;
if (tptr != NULL) {
arc4random_buf(buf, n);
return;
}
}
#endif
/* Make sure that we start out with b at a 4-byte alignment; plenty
* of CPUs care about this for 32-bit access. */
if (n >= 4 && ((ev_uintptr_t)b) & 3) {
ev_uint32_t u = arc4random();
int n_bytes = 4 - (((ev_uintptr_t)b) & 3);
memcpy(b, &u, n_bytes);
b += n_bytes;
n -= n_bytes;
}
while (n >= 4) {
*(ev_uint32_t*)b = arc4random();
b += 4;
n -= 4;
}
if (n) {
ev_uint32_t u = arc4random();
memcpy(b, &u, n);
}
#endif
}
#else /* !EVENT__HAVE_ARC4RANDOM { */
#ifdef EVENT__ssize_t
#define ssize_t EVENT__ssize_t
#endif
#define ARC4RANDOM_EXPORT static
#define ARC4_LOCK_() EVLOCK_LOCK(arc4rand_lock, 0)
#define ARC4_UNLOCK_() EVLOCK_UNLOCK(arc4rand_lock, 0)
#ifndef EVENT__DISABLE_THREAD_SUPPORT
static void *arc4rand_lock;
#endif
#define ARC4RANDOM_UINT32 ev_uint32_t
#define ARC4RANDOM_NOSTIR
#define ARC4RANDOM_NORANDOM
#define ARC4RANDOM_NOUNIFORM
#include "./arc4random.c"
#ifndef EVENT__DISABLE_THREAD_SUPPORT
int
evutil_secure_rng_global_setup_locks_(const int enable_locks)
{
EVTHREAD_SETUP_GLOBAL_LOCK(arc4rand_lock, 0);
return 0;
}
#endif
static void
evutil_free_secure_rng_globals_locks(void)
{
#ifndef EVENT__DISABLE_THREAD_SUPPORT
if (arc4rand_lock != NULL) {
EVTHREAD_FREE_LOCK(arc4rand_lock, 0);
arc4rand_lock = NULL;
}
#endif
return;
}
int
evutil_secure_rng_set_urandom_device_file(char *fname)
{
#ifdef TRY_SEED_URANDOM
ARC4_LOCK_();
arc4random_urandom_filename = fname;
ARC4_UNLOCK_();
#endif
return 0;
}
int
evutil_secure_rng_init(void)
{
int val;
ARC4_LOCK_();
val = (!arc4_stir()) ? 0 : -1;
ARC4_UNLOCK_();
return val;
}
static void
ev_arc4random_buf(void *buf, size_t n)
{
arc4random_buf(buf, n);
}
#endif /* } !EVENT__HAVE_ARC4RANDOM */
void
evutil_secure_rng_get_bytes(void *buf, size_t n)
{
ev_arc4random_buf(buf, n);
}
void
evutil_secure_rng_add_bytes(const char *buf, size_t n)
{
#if !defined(EVENT__HAVE_ARC4RANDOM) || defined(EVENT__HAVE_ARC4RANDOM_ADDRANDOM)
arc4random_addrandom((unsigned char*)buf,
n>(size_t)INT_MAX ? INT_MAX : (int)n);
#endif
}
void
evutil_free_secure_rng_globals_(void)
{
evutil_free_secure_rng_globals_locks();
}
