Import code from previous AssetBuilder version

thirdparty/libtommath/bn_mp_rand.c

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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 */