diff options
Diffstat (limited to 'libtommath/bn_mp_rand.c')
| -rw-r--r-- | libtommath/bn_mp_rand.c | 220 |
1 files changed, 22 insertions, 198 deletions
diff --git a/libtommath/bn_mp_rand.c b/libtommath/bn_mp_rand.c index 17aa5a2..7e9052c 100644 --- a/libtommath/bn_mp_rand.c +++ b/libtommath/bn_mp_rand.c @@ -1,222 +1,46 @@ #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 - */ +/* LibTomMath, multiple-precision integer library -- Tom St Denis */ +/* 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 +mp_err(*s_mp_rand_source)(void *out, size_t size) = s_mp_rand_platform; -static int s_read_arc4random(mp_digit *p) +void mp_rand_source(mp_err(*source)(void *out, size_t size)) { - 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; + s_mp_rand_source = (source == NULL) ? s_mp_rand_platform : source; } -#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) +mp_err mp_rand(mp_int *a, int digits) { - 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; + int i; + mp_err err; 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 ((err = mp_grow(a, digits)) != MP_OKAY) { + return err; + } - if ((res = mp_add_d(a, d, a)) != MP_OKAY) { - return res; + if ((err = s_mp_rand_source(a->dp, (size_t)digits * sizeof(mp_digit))) != MP_OKAY) { + return err; } - while (--digits > 0) { - if ((res = mp_lshd(a, 1)) != MP_OKAY) { - return res; + /* TODO: We ensure that the highest digit is nonzero. Should this be removed? */ + while ((a->dp[digits - 1] & MP_MASK) == 0u) { + if ((err = s_mp_rand_source(a->dp + digits - 1, sizeof(mp_digit))) != MP_OKAY) { + return err; } + } - if (mp_rand_digit(&d) != MP_OKAY) { - return MP_VAL; - } - if ((res = mp_add_d(a, d, a)) != MP_OKAY) { - return res; - } + a->used = digits; + for (i = 0; i < digits; ++i) { + a->dp[i] &= MP_MASK; } return MP_OKAY; } #endif - -/* ref: $Format:%D$ */ -/* git commit: $Format:%H$ */ -/* commit time: $Format:%ai$ */ |