Commit d2f894e4 authored by Philip Withnall's avatar Philip Withnall Committed by Olivier Crête

stun: Use libgcrypt to provide secure random number generation

Previously, a custom Mersenne Twister PRNG was used, which is not
securely random. In addition, its seeding fell back to wall-clock time,
which is typically predictable.

This uses libgcrypt on Linux but retains the Windows code which uses the
Windows crypt API.

Differential Revision: https://phabricator.freedesktop.org/D1610
parent d81c0d5f
......@@ -68,187 +68,23 @@ void nice_RAND_bytes (uint8_t *dst, int len)
}
#else
/* ------------- Start original implementation. ----------------- */
/* http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/MT2002/emt19937ar.html */
/*
A C-program for MT19937, with initialization improved 2002/1/26.
Coded by Takuji Nishimura and Makoto Matsumoto.
Before using, initialize the state by using init_genrand(seed)
or init_by_array(init_key, key_length).
Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
All rights reserved
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 names of its contributors may not be used to endorse or promote
products derived from this software without specific prior written
permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"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 COPYRIGHT OWNER OR
CONTRIBUTORS 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.
Any feedback is very welcome.
http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
*/
/* Period parameters */
#define N 624
#define M 397
#define MATRIX_A 0x9908b0dfUL /* constant vector a */
#define UPPER_MASK 0x80000000UL /* most significant w-r bits */
#define LOWER_MASK 0x7fffffffUL /* least significant r bits */
static unsigned long mt[N]; /* the array for the state vector */
static int mti=N+1; /* mti==N+1 means mt[N] is not initialized */
/* initializes mt[N] with a seed */
static void init_genrand(unsigned long s)
{
mt[0]= s & 0xffffffffUL;
for (mti=1; mti<N; mti++) {
mt[mti] = (1812433253UL * (mt[mti-1] ^ (mt[mti-1] >> 30)) + mti);
/* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
/* In the previous versions, MSBs of the seed affect */
/* only MSBs of the array mt[]. */
/* 2002/01/09 modified by Makoto Matsumoto */
mt[mti] &= 0xffffffffUL;
/* for >32 bit machines */
}
}
/* initialize by an array with array-length */
/* init_key is the array for initializing keys */
/* key_length is its length */
/* slight change for C++, 2004/2/26 */
static void init_by_array(unsigned long init_key[], int key_length)
{
int i, j, k;
init_genrand(19650218UL);
i=1; j=0;
k = (N>key_length ? N : key_length);
for (; k; k--) {
mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1664525UL))
+ init_key[j] + j; /* non linear */
mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
i++; j++;
if (i>=N) { mt[0] = mt[N-1]; i=1; }
if (j>=key_length) j=0;
}
for (k=N-1; k; k--) {
mt[i] = (mt[i] ^ ((mt[i-1] ^ (mt[i-1] >> 30)) * 1566083941UL))
- i; /* non linear */
mt[i] &= 0xffffffffUL; /* for WORDSIZE > 32 machines */
i++;
if (i>=N) { mt[0] = mt[N-1]; i=1; }
}
mt[0] = 0x80000000UL; /* MSB is 1; assuring non-zero initial array */
}
/* generates a random number on [0,0xffffffff]-interval */
static unsigned long genrand_int32(void)
{
unsigned long y;
static unsigned long mag01[2]={0x0UL, MATRIX_A};
/* mag01[x] = x * MATRIX_A for x=0,1 */
if (mti >= N) { /* generate N words at one time */
int kk;
if (mti == N+1) /* if init_genrand() has not been called, */
init_genrand(5489UL); /* a default initial seed is used */
for (kk=0;kk<N-M;kk++) {
y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1UL];
}
for (;kk<N-1;kk++) {
y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1UL];
}
y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1UL];
mti = 0;
}
y = mt[mti++];
/* Tempering */
y ^= (y >> 11);
y ^= (y << 7) & 0x9d2c5680UL;
y ^= (y << 15) & 0xefc60000UL;
y ^= (y >> 18);
return y;
}
/* These real versions are due to Isaku Wada, 2002/01/09 added */
/* ------------- End original implementation. ----------------- */
#include <stdio.h>
#include <time.h>
static int initialized = 0;
#include <gcrypt.h>
void nice_RAND_bytes (uint8_t *dst, int len)
{
int i;
if (!initialized) {
/* Seed the generator with an array from /dev/urandom if available
Otherwise use time() and clock() values */
FILE *urandom = fopen( "/dev/urandom", "rb" );
unsigned long init_key[10] = {};
int key_length = 0;
if (urandom) {
while (fread(&init_key[key_length++], sizeof(unsigned long), 1,
urandom) > 0 && key_length < 10);
fclose(urandom);
} else {
time_t t = time (NULL);
clock_t c = clock ();
unsigned long cl = c;
unsigned long tl = t;
init_key[0] = *((unsigned long *) dst);
init_key[1] = 0x6c69626e;
init_key[2] = 0x69636500;
init_key[3] = tl;
init_key[4] = cl;
key_length = 5;
/* Initialise libgcrypt. The application might do this first, but we need to
* do it otherwise. Abort if this fails, as we can’t do random number
* generation. */
if (!gcry_check_version (GCRYPT_VERSION))
abort ();
if (!gcry_control (GCRYCTL_INITIALIZATION_FINISHED_P))
{
gcry_control (GCRYCTL_DISABLE_SECMEM, 0);
gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
}
init_by_array(init_key, key_length);
initialized = 1;
}
for (i = 0; i < len; i++) {
dst[i] = genrand_int32 () & 0xFF;
}
gcry_randomize (dst, len, GCRY_STRONG_RANDOM);
}
#endif /* _WIN32 */
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