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#include "tommath_private.h"
#ifdef BN_MP_RAND_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
* LibTomMath is a library that provides multiple-precision
* integer arithmetic as well as number theoretic functionality.
*
* The library was designed directly after the MPI library by
* Michael Fromberger but has been written from scratch with
* additional optimizations in place.
*
* SPDX-License-Identifier: Unlicense
*/
/* First the OS-specific special cases
* - *BSD
* - Windows
*/
#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
#define MP_ARC4RANDOM
#define MP_GEN_RANDOM_MAX 0xffffffffu
#define MP_GEN_RANDOM_SHIFT 32
static int s_read_arc4random(mp_digit *p)
{
mp_digit d = 0, msk = 0;
do {
d <<= MP_GEN_RANDOM_SHIFT;
d |= ((mp_digit) arc4random());
msk <<= MP_GEN_RANDOM_SHIFT;
msk |= (MP_MASK & MP_GEN_RANDOM_MAX);
} while ((MP_MASK & msk) != MP_MASK);
*p = d;
return MP_OKAY;
}
#endif
#if defined(_WIN32) || defined(_WIN32_WCE)
#define MP_WIN_CSP
#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x0400
#endif
#ifdef _WIN32_WCE
#define UNDER_CE
#define ARM
#endif
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <wincrypt.h>
static HCRYPTPROV hProv = 0;
static void s_cleanup_win_csp(void)
{
CryptReleaseContext(hProv, 0);
hProv = 0;
}
static int s_read_win_csp(mp_digit *p)
{
int ret = -1;
if (hProv == 0) {
if (!CryptAcquireContext(&hProv, NULL, MS_DEF_PROV, PROV_RSA_FULL,
(CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET)) &&
!CryptAcquireContext(&hProv, NULL, MS_DEF_PROV, PROV_RSA_FULL,
CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET | CRYPT_NEWKEYSET)) {
hProv = 0;
return ret;
}
atexit(s_cleanup_win_csp);
}
if (CryptGenRandom(hProv, sizeof(*p), (void *)p) == TRUE) {
ret = MP_OKAY;
}
return ret;
}
#endif /* WIN32 */
#if !defined(MP_WIN_CSP) && defined(__linux__) && defined(__GLIBC_PREREQ)
#if __GLIBC_PREREQ(2, 25)
#define MP_GETRANDOM
#include <sys/random.h>
#include <errno.h>
static int s_read_getrandom(mp_digit *p)
{
int ret;
do {
ret = getrandom(p, sizeof(*p), 0);
} while ((ret == -1) && (errno == EINTR));
if (ret == sizeof(*p)) return MP_OKAY;
return -1;
}
#endif
#endif
/* We assume all platforms besides windows provide "/dev/urandom".
* In case yours doesn't, define MP_NO_DEV_URANDOM at compile-time.
*/
#if !defined(MP_WIN_CSP) && !defined(MP_NO_DEV_URANDOM)
#ifndef MP_DEV_URANDOM
#define MP_DEV_URANDOM "/dev/urandom"
#endif
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
static int s_read_dev_urandom(mp_digit *p)
{
ssize_t r;
int fd;
do {
fd = open(MP_DEV_URANDOM, O_RDONLY);
} while ((fd == -1) && (errno == EINTR));
if (fd == -1) return -1;
do {
r = read(fd, p, sizeof(*p));
} while ((r == -1) && (errno == EINTR));
close(fd);
if (r != sizeof(*p)) return -1;
return MP_OKAY;
}
#endif
#if defined(MP_PRNG_ENABLE_LTM_RNG)
unsigned long (*ltm_rng)(unsigned char *out, unsigned long outlen, void (*callback)(void));
void (*ltm_rng_callback)(void);
static int s_read_ltm_rng(mp_digit *p)
{
unsigned long ret;
if (ltm_rng == NULL) return -1;
ret = ltm_rng((void *)p, sizeof(*p), ltm_rng_callback);
if (ret != sizeof(*p)) return -1;
return MP_OKAY;
}
#endif
static int s_rand_digit(mp_digit *p)
{
int ret = -1;
#if defined(MP_ARC4RANDOM)
ret = s_read_arc4random(p);
if (ret == MP_OKAY) return ret;
#endif
#if defined(MP_WIN_CSP)
ret = s_read_win_csp(p);
if (ret == MP_OKAY) return ret;
#else
#if defined(MP_GETRANDOM)
ret = s_read_getrandom(p);
if (ret == MP_OKAY) return ret;
#endif
#if defined(MP_DEV_URANDOM)
ret = s_read_dev_urandom(p);
if (ret == MP_OKAY) return ret;
#endif
#endif /* MP_WIN_CSP */
#if defined(MP_PRNG_ENABLE_LTM_RNG)
ret = s_read_ltm_rng(p);
if (ret == MP_OKAY) return ret;
#endif
return ret;
}
/* makes a pseudo-random int of a given size */
int mp_rand_digit(mp_digit *r)
{
int ret = s_rand_digit(r);
*r &= MP_MASK;
return ret;
}
int mp_rand(mp_int *a, int digits)
{
int res;
mp_digit d;
mp_zero(a);
if (digits <= 0) {
return MP_OKAY;
}
/* first place a random non-zero digit */
do {
if (mp_rand_digit(&d) != MP_OKAY) {
return MP_VAL;
}
} while (d == 0u);
if ((res = mp_add_d(a, d, a)) != MP_OKAY) {
return res;
}
while (--digits > 0) {
if ((res = mp_lshd(a, 1)) != MP_OKAY) {
return res;
}
if (mp_rand_digit(&d) != MP_OKAY) {
return MP_VAL;
}
if ((res = mp_add_d(a, d, a)) != MP_OKAY) {
return res;
}
}
return MP_OKAY;
}
#endif
/* ref: HEAD -> master, tag: v1.1.0 */
/* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
/* commit time: 2019-01-28 20:32:32 +0100 */
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