Commit 63ea63eb authored by Rémi Denis-Courmont's avatar Rémi Denis-Courmont

Add nonce generator vlc_rand_bytes

parent 4e4b03cd
/*****************************************************************************
* vlc_rand.h: RNG
*****************************************************************************
* Copyright © 2007 Rémi Denis-Courmont
* $Id$
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
#if !defined( __LIBVLC__ )
#error You are not libvlc or one of its plugins. You cannot include this file
#endif
#ifndef _VLC_RAND_H
# define _VLC_RAND_H
VLC_EXPORT( void, vlc_rand_bytes, (void *buf, size_t len) );
#endif
......@@ -68,6 +68,7 @@ HEADERS_include = \
../include/vlc_os_specific.h \
../include/vlc_osd.h \
../include/vlc_playlist.h \
../include/vlc_rand.h \
../include/vlc_sout.h \
../include/vlc_stream.h \
../include/vlc_streaming.h \
......@@ -275,6 +276,7 @@ SOURCES_libvlc_common = \
text/iso_lang.c \
text/iso-639_def.h \
misc/md5.c \
misc/rand.c \
misc/mtime.c \
misc/block.c \
modules/modules.h \
......
......@@ -434,3 +434,4 @@ vout_vaControlDefault
vout_VarCallback
__xml_Create
xml_Delete
vlc_rand_bytes
/*****************************************************************************
* rand.c : non-predictible random bytes generator
*****************************************************************************
* Copyright © 2007 Rémi Denis-Courmont
* $Id$
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
*****************************************************************************/
#include <vlc/vlc.h>
#include <vlc_rand.h>
#ifndef WIN32
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <pthread.h>
#include <vlc_md5.h>
/*
* Pseudo-random number generator using a HMAC-MD5 in counter mode.
* Probably not very secure (expert patches welcome) but definitely
* better than rand() which is defined to be reproducible...
*/
#define BLOCK_SIZE 64
static uint8_t okey[BLOCK_SIZE], ikey[BLOCK_SIZE];
static void vlc_rand_init (void)
{
#if defined (__OpenBSD__) || defined (__OpenBSD_kernel__)
static const char randfile[] = "/dev/random";
#else
static const char randfile[] = "/dev/urandom";
#endif
uint8_t key[BLOCK_SIZE];
/* Get non-predictible value as key for HMAC */
int fd = open (randfile, O_RDONLY);
if (fd == -1)
return; /* Uho! */
for (size_t i = 0; i < sizeof (key);)
{
ssize_t val = read (fd, key + i, sizeof (key) - i);
if (val > 0)
i += val;
}
/* Precompute outer and inner keys for HMAC */
for (size_t i = 0; i < sizeof (key); i++)
{
okey[i] = key[i] ^ 0x5c;
ikey[i] = key[i] ^ 0x36;
}
close (fd);
}
void vlc_rand_bytes (void *buf, size_t len)
{
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
static uint64_t counter = 0;
struct md5_s md;
uint64_t stamp = NTPtime64 ();
while (len > 0)
{
uint64_t val;
pthread_mutex_lock (&lock);
if (counter == 0)
vlc_rand_init ();
val = counter++;
pthread_mutex_unlock (&lock);
InitMD5 (&md);
AddMD5 (&md, ikey, sizeof (ikey));
AddMD5 (&md, &stamp, sizeof (stamp));
AddMD5 (&md, &val, sizeof (val));
EndMD5 (&md);
if (len < sizeof (md.p_digest))
{
memcpy (buf, md.p_digest, len);
break;
}
memcpy (buf, md.p_digest, sizeof (md.p_digest));
len -= sizeof (md.p_digest);
buf = ((uint8_t *)buf) + sizeof (md.p_digest);
}
}
#else /* WIN32 */
#define _CRT_RAND_S
#include <stdlib.h>
void vlc_rand_bytes (void *buf, size_t len)
{
while (len > 0)
{
unsigned int val;
rand_s (&val);
if (len < sizeof (val))
{
memcpy (buf, &val, len);
break;
}
memcpy (buf, &val, sizeof (val));
}
}
#endif
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