207 lines
5.2 KiB
C
207 lines
5.2 KiB
C
/*
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* Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* This file has our secure PRNG code. On platforms that have arc4random(),
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* we just use that. Otherwise, we include arc4random.c as a bunch of static
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* functions, and wrap it lightly. We don't expose the arc4random*() APIs
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* because A) they aren't in our namespace, and B) it's not nice to name your
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* APIs after their implementations. We keep them in a separate file
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* so that other people can rip it out and use it for whatever.
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*/
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#include "event2/event-config.h"
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#include "evconfig-private.h"
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#include <limits.h>
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#include "util-internal.h"
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#include "evthread-internal.h"
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#ifdef EVENT__HAVE_ARC4RANDOM
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#include <stdlib.h>
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#include <string.h>
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int
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evutil_secure_rng_set_urandom_device_file(char *fname)
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{
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(void) fname;
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return -1;
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}
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int
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evutil_secure_rng_init(void)
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{
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/* call arc4random() now to force it to self-initialize */
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(void) arc4random();
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return 0;
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}
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#ifndef EVENT__DISABLE_THREAD_SUPPORT
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int
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evutil_secure_rng_global_setup_locks_(const int enable_locks)
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{
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return 0;
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}
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#endif
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static void
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evutil_free_secure_rng_globals_locks(void)
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{
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}
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static void
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ev_arc4random_buf(void *buf, size_t n)
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{
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#if defined(EVENT__HAVE_ARC4RANDOM_BUF) && !defined(__APPLE__)
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arc4random_buf(buf, n);
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return;
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#else
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unsigned char *b = buf;
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#if defined(EVENT__HAVE_ARC4RANDOM_BUF)
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/* OSX 10.7 introducd arc4random_buf, so if you build your program
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* there, you'll get surprised when older versions of OSX fail to run.
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* To solve this, we can check whether the function pointer is set,
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* and fall back otherwise. (OSX does this using some linker
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* trickery.)
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*/
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{
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void (*tptr)(void *,size_t) =
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(void (*)(void*,size_t))arc4random_buf;
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if (tptr != NULL) {
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arc4random_buf(buf, n);
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return;
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}
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}
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#endif
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/* Make sure that we start out with b at a 4-byte alignment; plenty
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* of CPUs care about this for 32-bit access. */
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if (n >= 4 && ((ev_uintptr_t)b) & 3) {
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ev_uint32_t u = arc4random();
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int n_bytes = 4 - (((ev_uintptr_t)b) & 3);
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memcpy(b, &u, n_bytes);
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b += n_bytes;
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n -= n_bytes;
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}
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while (n >= 4) {
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*(ev_uint32_t*)b = arc4random();
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b += 4;
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n -= 4;
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}
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if (n) {
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ev_uint32_t u = arc4random();
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memcpy(b, &u, n);
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}
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#endif
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}
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#else /* !EVENT__HAVE_ARC4RANDOM { */
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#ifdef EVENT__ssize_t
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#define ssize_t EVENT__ssize_t
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#endif
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#define ARC4RANDOM_EXPORT static
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#define ARC4_LOCK_() EVLOCK_LOCK(arc4rand_lock, 0)
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#define ARC4_UNLOCK_() EVLOCK_UNLOCK(arc4rand_lock, 0)
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#ifndef EVENT__DISABLE_THREAD_SUPPORT
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static void *arc4rand_lock;
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#endif
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#define ARC4RANDOM_UINT32 ev_uint32_t
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#define ARC4RANDOM_NOSTIR
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#define ARC4RANDOM_NORANDOM
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#define ARC4RANDOM_NOUNIFORM
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#include "./arc4random.c"
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#ifndef EVENT__DISABLE_THREAD_SUPPORT
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int
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evutil_secure_rng_global_setup_locks_(const int enable_locks)
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{
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EVTHREAD_SETUP_GLOBAL_LOCK(arc4rand_lock, 0);
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return 0;
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}
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#endif
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static void
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evutil_free_secure_rng_globals_locks(void)
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{
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#ifndef EVENT__DISABLE_THREAD_SUPPORT
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if (arc4rand_lock != NULL) {
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EVTHREAD_FREE_LOCK(arc4rand_lock, 0);
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arc4rand_lock = NULL;
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}
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#endif
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return;
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}
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int
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evutil_secure_rng_set_urandom_device_file(char *fname)
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{
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#ifdef TRY_SEED_URANDOM
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ARC4_LOCK_();
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arc4random_urandom_filename = fname;
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ARC4_UNLOCK_();
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#endif
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return 0;
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}
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int
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evutil_secure_rng_init(void)
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{
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int val;
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ARC4_LOCK_();
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if (!arc4_seeded_ok)
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arc4_stir();
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val = arc4_seeded_ok ? 0 : -1;
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ARC4_UNLOCK_();
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return val;
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}
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static void
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ev_arc4random_buf(void *buf, size_t n)
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{
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arc4random_buf(buf, n);
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}
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#endif /* } !EVENT__HAVE_ARC4RANDOM */
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void
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evutil_secure_rng_get_bytes(void *buf, size_t n)
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{
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ev_arc4random_buf(buf, n);
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}
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void
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evutil_secure_rng_add_bytes(const char *buf, size_t n)
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{
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arc4random_addrandom((unsigned char*)buf,
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n>(size_t)INT_MAX ? INT_MAX : (int)n);
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}
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void
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evutil_free_secure_rng_globals_(void)
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{
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evutil_free_secure_rng_globals_locks();
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}
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