michael@0: /*
michael@0:  * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
michael@0:  *
michael@0:  * Redistribution and use in source and binary forms, with or without
michael@0:  * modification, are permitted provided that the following conditions
michael@0:  * are met:
michael@0:  * 1. Redistributions of source code must retain the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer.
michael@0:  * 2. Redistributions in binary form must reproduce the above copyright
michael@0:  *    notice, this list of conditions and the following disclaimer in the
michael@0:  *    documentation and/or other materials provided with the distribution.
michael@0:  * 3. The name of the author may not be used to endorse or promote products
michael@0:  *    derived from this software without specific prior written permission.
michael@0:  *
michael@0:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
michael@0:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
michael@0:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
michael@0:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
michael@0:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
michael@0:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
michael@0:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0:  */
michael@0: 
michael@0: /* This file has our secure PRNG code.  On platforms that have arc4random(),
michael@0:  * we just use that.  Otherwise, we include arc4random.c as a bunch of static
michael@0:  * functions, and wrap it lightly.  We don't expose the arc4random*() APIs
michael@0:  * because A) they aren't in our namespace, and B) it's not nice to name your
michael@0:  * APIs after their implementations.  We keep them in a separate file
michael@0:  * so that other people can rip it out and use it for whatever.
michael@0:  */
michael@0: 
michael@0: #include "event2/event-config.h"
michael@0: 
michael@0: #include <limits.h>
michael@0: 
michael@0: #include "util-internal.h"
michael@0: #include "evthread-internal.h"
michael@0: 
michael@0: #ifdef _EVENT_HAVE_ARC4RANDOM
michael@0: #include <stdlib.h>
michael@0: #include <string.h>
michael@0: int
michael@0: evutil_secure_rng_init(void)
michael@0: {
michael@0: 	/* call arc4random() now to force it to self-initialize */
michael@0: 	(void) arc4random();
michael@0: 	return 0;
michael@0: }
michael@0: int
michael@0: evutil_secure_rng_global_setup_locks_(const int enable_locks)
michael@0: {
michael@0: 	return 0;
michael@0: }
michael@0: 
michael@0: static void
michael@0: ev_arc4random_buf(void *buf, size_t n)
michael@0: {
michael@0: #if defined(_EVENT_HAVE_ARC4RANDOM_BUF) && !defined(__APPLE__)
michael@0: 	return arc4random_buf(buf, n);
michael@0: #else
michael@0: 	unsigned char *b = buf;
michael@0: 
michael@0: 	/* Make sure that we start out with b at a 4-byte alignment; plenty
michael@0: 	 * of CPUs care about this for 32-bit access. */
michael@0: 	if (n >= 4 && ((ev_uintptr_t)b) & 3) {
michael@0: 		ev_uint32_t u = arc4random();
michael@0: 		int n_bytes = 4 - (((ev_uintptr_t)b) & 3);
michael@0: 		memcpy(b, &u, n_bytes);
michael@0: 		b += n_bytes;
michael@0: 		n -= n_bytes;
michael@0: 	}
michael@0: 	while (n >= 4) {
michael@0: 		*(ev_uint32_t*)b = arc4random();
michael@0: 		b += 4;
michael@0: 		n -= 4;
michael@0: 	}
michael@0: 	if (n) {
michael@0: 		ev_uint32_t u = arc4random();
michael@0: 		memcpy(b, &u, n);
michael@0: 	}
michael@0: #endif
michael@0: }
michael@0: 
michael@0: #else /* !_EVENT_HAVE_ARC4RANDOM { */
michael@0: 
michael@0: #ifdef _EVENT_ssize_t
michael@0: #define ssize_t _EVENT_SSIZE_t
michael@0: #endif
michael@0: #define ARC4RANDOM_EXPORT static
michael@0: #define _ARC4_LOCK() EVLOCK_LOCK(arc4rand_lock, 0)
michael@0: #define _ARC4_UNLOCK() EVLOCK_UNLOCK(arc4rand_lock, 0)
michael@0: #ifndef _EVENT_DISABLE_THREAD_SUPPORT
michael@0: static void *arc4rand_lock;
michael@0: #endif
michael@0: 
michael@0: #define ARC4RANDOM_UINT32 ev_uint32_t
michael@0: #define ARC4RANDOM_NOSTIR
michael@0: #define ARC4RANDOM_NORANDOM
michael@0: #define ARC4RANDOM_NOUNIFORM
michael@0: 
michael@0: #include "./arc4random.c"
michael@0: 
michael@0: #ifndef _EVENT_DISABLE_THREAD_SUPPORT
michael@0: int
michael@0: evutil_secure_rng_global_setup_locks_(const int enable_locks)
michael@0: {
michael@0: 	EVTHREAD_SETUP_GLOBAL_LOCK(arc4rand_lock, 0);
michael@0: 	return 0;
michael@0: }
michael@0: #endif
michael@0: 
michael@0: int
michael@0: evutil_secure_rng_init(void)
michael@0: {
michael@0: 	int val;
michael@0: 
michael@0: 	_ARC4_LOCK();
michael@0: 	if (!arc4_seeded_ok)
michael@0: 		arc4_stir();
michael@0: 	val = arc4_seeded_ok ? 0 : -1;
michael@0: 	_ARC4_UNLOCK();
michael@0: 	return val;
michael@0: }
michael@0: 
michael@0: static void
michael@0: ev_arc4random_buf(void *buf, size_t n)
michael@0: {
michael@0: 	arc4random_buf(buf, n);
michael@0: }
michael@0: 
michael@0: #endif /* } !_EVENT_HAVE_ARC4RANDOM */
michael@0: 
michael@0: void
michael@0: evutil_secure_rng_get_bytes(void *buf, size_t n)
michael@0: {
michael@0: 	ev_arc4random_buf(buf, n);
michael@0: }
michael@0: 
michael@0: #ifndef __OpenBSD__
michael@0: void
michael@0: evutil_secure_rng_add_bytes(const char *buf, size_t n)
michael@0: {
michael@0: 	arc4random_addrandom((unsigned char*)buf,
michael@0: 	    n>(size_t)INT_MAX ? INT_MAX : (int)n);
michael@0: }
michael@0: #endif