Steffen Jaeckel
GitHub
commit
71c5c8ac4b
184
bn_mp_rand.c
184
bn_mp_rand.c
@ -13,34 +13,171 @@
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* guarantee it works.
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*/
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#if defined(MP_8BIT) || defined(MP_16BIT)
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#define MP_GEN_RANDOM_SHIFT DIGIT_BIT
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#else
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#if MP_GEN_RANDOM_MAX == 0xffffffffu
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/* First the OS-specific special cases
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* - *BSD
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* - Windows
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*/
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#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
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#define MP_ARC4RANDOM
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#define MP_GEN_RANDOM_MAX 0xffffffffu
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#define MP_GEN_RANDOM_SHIFT 32
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#elif MP_GEN_RANDOM_MAX == 32767
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/* SHRT_MAX */
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#define MP_GEN_RANDOM_SHIFT 15
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#elif MP_GEN_RANDOM_MAX == 2147483647
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/* INT_MAX */
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#define MP_GEN_RANDOM_SHIFT 31
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#elif !defined(MP_GEN_RANDOM_SHIFT)
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#error Thou shalt define their own valid MP_GEN_RANDOM_SHIFT
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#endif
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#endif
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/* makes a pseudo-random int of a given size */
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static mp_digit s_gen_random(void)
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static int s_read_arc4random(mp_digit* p)
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{
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mp_digit d = 0, msk = 0;
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do {
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d <<= MP_GEN_RANDOM_SHIFT;
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d |= ((mp_digit) MP_GEN_RANDOM());
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d |= ((mp_digit) arc4random());
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msk <<= MP_GEN_RANDOM_SHIFT;
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msk |= (MP_MASK & MP_GEN_RANDOM_MAX);
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} while ((MP_MASK & msk) != MP_MASK);
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d &= MP_MASK;
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return d;
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*p = d;
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return MP_OKAY;
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}
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#endif
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#if defined(_WIN32) || defined(_WIN32_WCE)
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#define MP_WIN_CSP
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#ifndef _WIN32_WINNT
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#define _WIN32_WINNT 0x0400
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#endif
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#ifdef _WIN32_WCE
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#define UNDER_CE
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#define ARM
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#endif
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#define WIN32_LEAN_AND_MEAN
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#include <windows.h>
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#include <wincrypt.h>
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static HCRYPTPROV hProv = 0;
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static void s_cleanup_win_csp(void)
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{
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CryptReleaseContext(hProv, 0);
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hProv = 0;
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}
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static int s_read_win_csp(mp_digit* p)
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{
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int ret = -1;
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if (hProv == 0) {
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if (!CryptAcquireContext(&hProv, NULL, MS_DEF_PROV, PROV_RSA_FULL,
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(CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET)) &&
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!CryptAcquireContext (&hProv, NULL, MS_DEF_PROV, PROV_RSA_FULL,
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CRYPT_VERIFYCONTEXT | CRYPT_MACHINE_KEYSET | CRYPT_NEWKEYSET)) {
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hProv = 0;
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return ret;
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}
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atexit(s_cleanup_win_csp);
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}
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if (CryptGenRandom(hProv, sizeof(*p), (void*)p) == TRUE) {
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ret = MP_OKAY;
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}
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return ret;
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}
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#endif /* WIN32 */
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#if !defined(MP_WIN_CSP) && defined(__linux__) && defined(__GLIBC_PREREQ)
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#if __GLIBC_PREREQ(2, 25)
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#define MP_GETRANDOM
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#include <sys/random.h>
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#include <errno.h>
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static int s_read_getrandom(mp_digit* p)
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{
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int ret;
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do {
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ret = getrandom(p, sizeof(*p), 0);
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} while((ret == -1) && (errno == EINTR));
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if (ret == sizeof(*p)) return MP_OKAY;
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return -1;
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}
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#endif
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#endif
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/* We assume all platforms besides windows provide "/dev/urandom".
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* In case yours doesn't, define MP_NO_DEV_URANDOM at compile-time.
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*/
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#if !defined(MP_WIN_CSP) && !defined(MP_NO_DEV_URANDOM)
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#ifndef MP_DEV_URANDOM
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#define MP_DEV_URANDOM "/dev/urandom"
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#endif
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#include <fcntl.h>
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#include <errno.h>
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#include <unistd.h>
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static int s_read_dev_urandom(mp_digit* p)
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{
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ssize_t r;
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int fd;
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do {
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fd = open(MP_DEV_URANDOM, O_RDONLY);
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} while((fd == -1) && (errno == EINTR));
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if (fd == -1) return -1;
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do {
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r = read(fd, p, sizeof(*p));
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} while((r == -1) && (errno == EINTR));
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close(fd);
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if (r != sizeof(*p)) return -1;
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return MP_OKAY;
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}
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#endif
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#if defined(MP_PRNG_ENABLE_LTM_RNG)
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unsigned long (*ltm_rng)(unsigned char *out, unsigned long outlen, void (*callback)(void));
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void (*ltm_rng_callback)(void);
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static int s_read_ltm_rng(mp_digit* p)
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{
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unsigned long ret;
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if (ltm_rng == NULL) return -1;
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ret = ltm_rng((void*)p, sizeof(*p), ltm_rng_callback);
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if (ret != sizeof(*p)) return -1;
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return MP_OKAY;
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}
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#endif
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static int s_rand_digit(mp_digit* p)
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{
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int ret = -1;
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#if defined(MP_ARC4RANDOM)
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ret = s_read_arc4random(p);
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if (ret == MP_OKAY) return ret;
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#endif
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#if defined(MP_WIN_CSP)
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ret = s_read_win_csp(p);
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if (ret == MP_OKAY) return ret;
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#else
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#if defined(MP_GETRANDOM)
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ret = s_read_getrandom(p);
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if (ret == MP_OKAY) return ret;
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#endif
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#if defined(MP_DEV_URANDOM)
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ret = s_read_dev_urandom(p);
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if (ret == MP_OKAY) return ret;
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#endif
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#endif /* MP_WIN_CSP */
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#if defined(MP_PRNG_ENABLE_LTM_RNG)
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ret = s_read_ltm_rng(p);
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if (ret == MP_OKAY) return ret;
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#endif
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return ret;
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}
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/* makes a pseudo-random int of a given size */
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static int s_gen_random(mp_digit *r)
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{
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int ret = s_rand_digit(r);
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*r &= MP_MASK;
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return ret;
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}
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int mp_rand(mp_int *a, int digits)
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@ -55,7 +192,9 @@ int mp_rand(mp_int *a, int digits)
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/* first place a random non-zero digit */
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do {
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d = s_gen_random();
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if (s_gen_random(&d) != MP_OKAY) {
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return MP_VAL;
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}
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} while (d == 0u);
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if ((res = mp_add_d(a, d, a)) != MP_OKAY) {
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@ -67,7 +206,10 @@ int mp_rand(mp_int *a, int digits)
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return res;
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}
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if ((res = mp_add_d(a, s_gen_random(), a)) != MP_OKAY) {
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if (s_gen_random(&d) != MP_OKAY) {
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return MP_VAL;
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}
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if ((res = mp_add_d(a, d, a)) != MP_OKAY) {
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return res;
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}
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}
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20
tommath.h
20
tommath.h
@ -100,18 +100,6 @@ typedef uint_least32_t mp_min_u32;
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typedef mp_digit mp_min_u32;
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#endif
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/* use arc4random on platforms that support it */
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#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__DragonFly__)
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# define MP_GEN_RANDOM() arc4random()
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# define MP_GEN_RANDOM_MAX 0xffffffffu
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#endif
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/* use rand() as fall-back if there's no better rand function */
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#ifndef MP_GEN_RANDOM
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# define MP_GEN_RANDOM() rand()
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# define MP_GEN_RANDOM_MAX RAND_MAX
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#endif
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#define MP_DIGIT_BIT DIGIT_BIT
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#define MP_MASK ((((mp_digit)1)<<((mp_digit)DIGIT_BIT))-((mp_digit)1))
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#define MP_DIGIT_MAX MP_MASK
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@ -287,6 +275,14 @@ int mp_cnt_lsb(const mp_int *a);
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/* makes a pseudo-random int of a given size */
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int mp_rand(mp_int *a, int digits);
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#ifdef MP_PRNG_ENABLE_LTM_RNG
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/* as last resort we will fall back to libtomcrypt's rng_get_bytes()
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* in case you don't use libtomcrypt or use it w/o rng_get_bytes()
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* you have to implement it somewhere else, as it's required */
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extern unsigned long (*ltm_rng)(unsigned char *out, unsigned long outlen, void (*callback)(void));
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extern void (*ltm_rng_callback)(void);
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#endif
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/* ---> binary operations <--- */
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/* c = a XOR b */
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int mp_xor(const mp_int *a, const mp_int *b, mp_int *c);
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