Imported Upstream version 4.8.0.309

Former-commit-id: 5f9c6ae75f295e057a7d2971f3a6df4656fa8850

external/boringssl/crypto/rand/CMakeLists.txt

@@ -0,0 +1,24 @@
+include_directories(../../include)
+
+if (${ARCH} STREQUAL "x86_64")
+  set(
+    RAND_ARCH_SOURCES
+
+    rdrand-x86_64.${ASM_EXT}
+  )
+endif()
+
+add_library(
+  rand
+
+  OBJECT
+
+  deterministic.c
+  rand.c
+  urandom.c
+  windows.c
+
+  ${RAND_ARCH_SOURCES}
+)
+
+perlasm(rdrand-x86_64.${ASM_EXT} asm/rdrand-x86_64.pl)

external/boringssl/crypto/rand/asm/rdrand-x86_64.pl

@@ -0,0 +1,75 @@
+#!/usr/bin/env perl
+
+# Copyright (c) 2015, Google Inc.
+#
+# Permission to use, copy, modify, and/or distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+# SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+# OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+$flavour = shift;
+$output  = shift;
+if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
+
+$0 =~ m/(.*[\/\\])[^\/\\]+$/; $dir=$1;
+( $xlate="${dir}../../perlasm/x86_64-xlate.pl" and -f $xlate) or
+die "can't locate x86_64-xlate.pl";
+
+open OUT,"| \"$^X\" $xlate $flavour $output";
+*STDOUT=*OUT;
+
+print<<___;
+.text
+
+# CRYPTO_rdrand writes eight bytes of random data from the hardware RNG to
+# |out|. It returns one on success or zero on hardware failure.
+# int CRYPTO_rdrand(uint8_t out[8]);
+.globl	CRYPTO_rdrand
+.type	CRYPTO_rdrand,\@function,1
+.align	16
+CRYPTO_rdrand:
+	xorq %rax, %rax
+	# This is rdrand %rcx. It sets rcx to a random value and sets the carry
+	# flag on success.
+	.byte 0x48, 0x0f, 0xc7, 0xf1
+	# An add-with-carry of zero effectively sets %rax to the carry flag.
+	adcq %rax, %rax
+	movq %rcx, 0(%rdi)
+	retq
+
+# CRYPTO_rdrand_multiple8_buf fills |len| bytes at |buf| with random data from
+# the hardware RNG. The |len| argument must be a multiple of eight. It returns
+# one on success and zero on hardware failure.
+# int CRYPTO_rdrand_multiple8_buf(uint8_t *buf, size_t len);
+.globl CRYPTO_rdrand_multiple8_buf
+.type CRYPTO_rdrand_multiple8_buf,\@function,2
+.align 16
+CRYPTO_rdrand_multiple8_buf:
+	test %rsi, %rsi
+	jz .Lout
+	movq \$8, %rdx
+.Lloop:
+	# This is rdrand %rcx. It sets rcx to a random value and sets the carry
+	# flag on success.
+	.byte 0x48, 0x0f, 0xc7, 0xf1
+	jnc .Lerr
+	movq %rcx, 0(%rdi)
+	addq %rdx, %rdi
+	subq %rdx, %rsi
+	jnz .Lloop
+.Lout:
+	movq \$1, %rax
+	retq
+.Lerr:
+	xorq %rax, %rax
+	retq
+___
+
+close STDOUT;	# flush

external/boringssl/crypto/rand/deterministic.c

@@ -0,0 +1,49 @@
+/* Copyright (c) 2016, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/rand.h>
+
+#if defined(BORINGSSL_UNSAFE_FUZZER_MODE)
+
+#include <string.h>
+
+#include <openssl/chacha.h>
+
+#include "internal.h"
+
+
+/* g_num_calls is the number of calls to |CRYPTO_sysrand| that have occured.
+ *
+ * TODO(davidben): This is intentionally not thread-safe. If the fuzzer mode is
+ * ever used in a multi-threaded program, replace this with a thread-local. (A
+ * mutex would not be deterministic.) */
+static uint64_t g_num_calls = 0;
+
+void RAND_cleanup(void) {}
+
+void RAND_reset_for_fuzzing(void) { g_num_calls = 0; }
+
+void CRYPTO_sysrand(uint8_t *out, size_t requested) {
+  static const uint8_t kZeroKey[32];
+
+  uint8_t nonce[12];
+  memset(nonce, 0, sizeof(nonce));
+  memcpy(nonce, &g_num_calls, sizeof(g_num_calls));
+
+  memset(out, 0, requested);
+  CRYPTO_chacha_20(out, out, requested, kZeroKey, nonce, 0);
+  g_num_calls++;
+}
+
+#endif  /* BORINGSSL_UNSAFE_FUZZER_MODE */

external/boringssl/crypto/rand/internal.h

@@ -0,0 +1,32 @@
+/* Copyright (c) 2015, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#ifndef OPENSSL_HEADER_CRYPTO_RAND_INTERNAL_H
+#define OPENSSL_HEADER_CRYPTO_RAND_INTERNAL_H
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+
+/* CRYPTO_sysrand fills |len| bytes at |buf| with entropy from the operating
+ * system. */
+void CRYPTO_sysrand(uint8_t *buf, size_t len);
+
+
+#if defined(__cplusplus)
+}  /* extern C */
+#endif
+
+#endif  /* OPENSSL_HEADER_CRYPTO_RAND_INTERNAL_H */

external/boringssl/crypto/rand/rand.c

@@ -0,0 +1,242 @@
+/* Copyright (c) 2014, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/rand.h>
+
+#include <assert.h>
+#include <limits.h>
+#include <string.h>
+
+#include <openssl/chacha.h>
+#include <openssl/cpu.h>
+#include <openssl/mem.h>
+
+#include "internal.h"
+#include "../internal.h"
+
+
+/* It's assumed that the operating system always has an unfailing source of
+ * entropy which is accessed via |CRYPTO_sysrand|. (If the operating system
+ * entropy source fails, it's up to |CRYPTO_sysrand| to abort the process—we
+ * don't try to handle it.)
+ *
+ * In addition, the hardware may provide a low-latency RNG. Intel's rdrand
+ * instruction is the canonical example of this. When a hardware RNG is
+ * available we don't need to worry about an RNG failure arising from fork()ing
+ * the process or moving a VM, so we can keep thread-local RNG state and XOR
+ * the hardware entropy in.
+ *
+ * (We assume that the OS entropy is safe from fork()ing and VM duplication.
+ * This might be a bit of a leap of faith, esp on Windows, but there's nothing
+ * that we can do about it.) */
+
+/* rand_thread_state contains the per-thread state for the RNG. This is only
+ * used if the system has support for a hardware RNG. */
+struct rand_thread_state {
+  uint8_t key[32];
+  uint64_t calls_used;
+  size_t bytes_used;
+  uint8_t partial_block[64];
+  unsigned partial_block_used;
+};
+
+/* kMaxCallsPerRefresh is the maximum number of |RAND_bytes| calls that we'll
+ * serve before reading a new key from the operating system. This only applies
+ * if we have a hardware RNG. */
+static const unsigned kMaxCallsPerRefresh = 1024;
+
+/* kMaxBytesPerRefresh is the maximum number of bytes that we'll return from
+ * |RAND_bytes| before reading a new key from the operating system. This only
+ * applies if we have a hardware RNG. */
+static const uint64_t kMaxBytesPerRefresh = 1024 * 1024;
+
+/* rand_thread_state_free frees a |rand_thread_state|. This is called when a
+ * thread exits. */
+static void rand_thread_state_free(void *state) {
+  if (state == NULL) {
+    return;
+  }
+
+  OPENSSL_cleanse(state, sizeof(struct rand_thread_state));
+  OPENSSL_free(state);
+}
+
+#if defined(OPENSSL_X86_64) && !defined(OPENSSL_NO_ASM) && \
+    !defined(BORINGSSL_UNSAFE_FUZZER_MODE)
+
+/* These functions are defined in asm/rdrand-x86_64.pl */
+extern int CRYPTO_rdrand(uint8_t out[8]);
+extern int CRYPTO_rdrand_multiple8_buf(uint8_t *buf, size_t len);
+
+static int have_rdrand(void) {
+  return (OPENSSL_ia32cap_P[1] & (1u << 30)) != 0;
+}
+
+static int hwrand(uint8_t *buf, size_t len) {
+  if (!have_rdrand()) {
+    return 0;
+  }
+
+  const size_t len_multiple8 = len & ~7;
+  if (!CRYPTO_rdrand_multiple8_buf(buf, len_multiple8)) {
+    return 0;
+  }
+  len -= len_multiple8;
+
+  if (len != 0) {
+    assert(len < 8);
+
+    uint8_t rand_buf[8];
+    if (!CRYPTO_rdrand(rand_buf)) {
+      return 0;
+    }
+    memcpy(buf + len_multiple8, rand_buf, len);
+  }
+
+  return 1;
+}
+
+#else
+
+static int hwrand(uint8_t *buf, size_t len) {
+  return 0;
+}
+
+#endif
+
+int RAND_bytes(uint8_t *buf, size_t len) {
+  if (len == 0) {
+    return 1;
+  }
+
+  if (!hwrand(buf, len)) {
+    /* Without a hardware RNG to save us from address-space duplication, the OS
+     * entropy is used directly. */
+    CRYPTO_sysrand(buf, len);
+    return 1;
+  }
+
+  struct rand_thread_state *state =
+      CRYPTO_get_thread_local(OPENSSL_THREAD_LOCAL_RAND);
+  if (state == NULL) {
+    state = OPENSSL_malloc(sizeof(struct rand_thread_state));
+    if (state == NULL ||
+        !CRYPTO_set_thread_local(OPENSSL_THREAD_LOCAL_RAND, state,
+                                 rand_thread_state_free)) {
+      CRYPTO_sysrand(buf, len);
+      return 1;
+    }
+
+    memset(state->partial_block, 0, sizeof(state->partial_block));
+    state->calls_used = kMaxCallsPerRefresh;
+  }
+
+  if (state->calls_used >= kMaxCallsPerRefresh ||
+      state->bytes_used >= kMaxBytesPerRefresh) {
+    CRYPTO_sysrand(state->key, sizeof(state->key));
+    state->calls_used = 0;
+    state->bytes_used = 0;
+    state->partial_block_used = sizeof(state->partial_block);
+  }
+
+  if (len >= sizeof(state->partial_block)) {
+    size_t remaining = len;
+    while (remaining > 0) {
+      /* kMaxBytesPerCall is only 2GB, while ChaCha can handle 256GB. But this
+       * is sufficient and easier on 32-bit. */
+      static const size_t kMaxBytesPerCall = 0x80000000;
+      size_t todo = remaining;
+      if (todo > kMaxBytesPerCall) {
+        todo = kMaxBytesPerCall;
+      }
+      uint8_t nonce[12];
+      memset(nonce, 0, 4);
+      memcpy(nonce + 4, &state->calls_used, sizeof(state->calls_used));
+      CRYPTO_chacha_20(buf, buf, todo, state->key, nonce, 0);
+      buf += todo;
+      remaining -= todo;
+      state->calls_used++;
+    }
+  } else {
+    if (sizeof(state->partial_block) - state->partial_block_used < len) {
+      uint8_t nonce[12];
+      memset(nonce, 0, 4);
+      memcpy(nonce + 4, &state->calls_used, sizeof(state->calls_used));
+      CRYPTO_chacha_20(state->partial_block, state->partial_block,
+                       sizeof(state->partial_block), state->key, nonce, 0);
+      state->partial_block_used = 0;
+    }
+
+    unsigned i;
+    for (i = 0; i < len; i++) {
+      buf[i] ^= state->partial_block[state->partial_block_used++];
+    }
+    state->calls_used++;
+  }
+  state->bytes_used += len;
+
+  return 1;
+}
+
+int RAND_pseudo_bytes(uint8_t *buf, size_t len) {
+  return RAND_bytes(buf, len);
+}
+
+void RAND_seed(const void *buf, int num) {
+  /* OpenSSH calls |RAND_seed| before jailing on the assumption that any needed
+   * file descriptors etc will be opened. */
+  uint8_t unused;
+  RAND_bytes(&unused, sizeof(unused));
+}
+
+int RAND_load_file(const char *path, long num) {
+  if (num < 0) {  /* read the "whole file" */
+    return 1;
+  } else if (num <= INT_MAX) {
+    return (int) num;
+  } else {
+    return INT_MAX;
+  }
+}
+
+const char *RAND_file_name(char *buf, size_t num) { return NULL; }
+
+void RAND_add(const void *buf, int num, double entropy) {}
+
+int RAND_egd(const char *path) {
+  return 255;
+}
+
+int RAND_poll(void) {
+  return 1;
+}
+
+int RAND_status(void) {
+  return 1;
+}
+
+static const struct rand_meth_st kSSLeayMethod = {
+  RAND_seed,
+  RAND_bytes,
+  RAND_cleanup,
+  RAND_add,
+  RAND_pseudo_bytes,
+  RAND_status,
+};
+
+RAND_METHOD *RAND_SSLeay(void) {
+  return (RAND_METHOD*) &kSSLeayMethod;
+}
+
+void RAND_set_rand_method(const RAND_METHOD *method) {}

external/boringssl/crypto/rand/urandom.c

@@ -0,0 +1,223 @@
+/* Copyright (c) 2014, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/rand.h>
+
+#if !defined(OPENSSL_WINDOWS) && !defined(BORINGSSL_UNSAFE_FUZZER_MODE)
+
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <openssl/thread.h>
+#include <openssl/mem.h>
+
+#include "internal.h"
+#include "../internal.h"
+
+
+/* This file implements a PRNG by reading from /dev/urandom, optionally with a
+ * buffer, which is unsafe across |fork|. */
+
+#define BUF_SIZE 4096
+
+/* rand_buffer contains unused, random bytes, some of which may have been
+ * consumed already. */
+struct rand_buffer {
+  size_t used;
+  uint8_t rand[BUF_SIZE];
+};
+
+/* requested_lock is used to protect the |*_requested| variables. */
+static struct CRYPTO_STATIC_MUTEX requested_lock = CRYPTO_STATIC_MUTEX_INIT;
+
+/* urandom_fd_requested is set by |RAND_set_urandom_fd|.  It's protected by
+ * |requested_lock|. */
+static int urandom_fd_requested = -2;
+
+/* urandom_fd is a file descriptor to /dev/urandom. It's protected by |once|. */
+static int urandom_fd = -2;
+
+/* urandom_buffering_requested is set by |RAND_enable_fork_unsafe_buffering|.
+ * It's protected by |requested_lock|. */
+static int urandom_buffering_requested = 0;
+
+/* urandom_buffering controls whether buffering is enabled (1) or not (0). This
+ * is protected by |once|. */
+static int urandom_buffering = 0;
+
+static CRYPTO_once_t once = CRYPTO_ONCE_INIT;
+
+/* init_once initializes the state of this module to values previously
+ * requested. This is the only function that modifies |urandom_fd| and
+ * |urandom_buffering|, whose values may be read safely after calling the
+ * once. */
+static void init_once(void) {
+  CRYPTO_STATIC_MUTEX_lock_read(&requested_lock);
+  urandom_buffering = urandom_buffering_requested;
+  int fd = urandom_fd_requested;
+  CRYPTO_STATIC_MUTEX_unlock_read(&requested_lock);
+
+  if (fd == -2) {
+    do {
+      fd = open("/dev/urandom", O_RDONLY);
+    } while (fd == -1 && errno == EINTR);
+  }
+
+  if (fd < 0) {
+    abort();
+  }
+
+  int flags = fcntl(fd, F_GETFD);
+  if (flags == -1) {
+    /* Native Client doesn't implement |fcntl|. */
+    if (errno != ENOSYS) {
+      abort();
+    }
+  } else {
+    flags |= FD_CLOEXEC;
+    if (fcntl(fd, F_SETFD, flags) == -1) {
+      abort();
+    }
+  }
+  urandom_fd = fd;
+}
+
+void RAND_cleanup(void) {}
+
+void RAND_set_urandom_fd(int fd) {
+  fd = dup(fd);
+  if (fd < 0) {
+    abort();
+  }
+
+  CRYPTO_STATIC_MUTEX_lock_write(&requested_lock);
+  urandom_fd_requested = fd;
+  CRYPTO_STATIC_MUTEX_unlock_write(&requested_lock);
+
+  CRYPTO_once(&once, init_once);
+  if (urandom_fd != fd) {
+    abort();  // Already initialized.
+  }
+}
+
+void RAND_enable_fork_unsafe_buffering(int fd) {
+  if (fd >= 0) {
+    fd = dup(fd);
+    if (fd < 0) {
+      abort();
+    }
+  } else {
+    fd = -2;
+  }
+
+  CRYPTO_STATIC_MUTEX_lock_write(&requested_lock);
+  urandom_buffering_requested = 1;
+  urandom_fd_requested = fd;
+  CRYPTO_STATIC_MUTEX_unlock_write(&requested_lock);
+
+  CRYPTO_once(&once, init_once);
+  if (urandom_buffering != 1 || (fd >= 0 && urandom_fd != fd)) {
+    abort();  // Already initialized.
+  }
+}
+
+static struct rand_buffer *get_thread_local_buffer(void) {
+  struct rand_buffer *buf =
+      CRYPTO_get_thread_local(OPENSSL_THREAD_LOCAL_URANDOM_BUF);
+  if (buf != NULL) {
+    return buf;
+  }
+
+  buf = OPENSSL_malloc(sizeof(struct rand_buffer));
+  if (buf == NULL) {
+    return NULL;
+  }
+  buf->used = BUF_SIZE;  /* To trigger a |read_full| on first use. */
+  if (!CRYPTO_set_thread_local(OPENSSL_THREAD_LOCAL_URANDOM_BUF, buf,
+                               OPENSSL_free)) {
+    OPENSSL_free(buf);
+    return NULL;
+  }
+
+  return buf;
+}
+
+/* read_full reads exactly |len| bytes from |fd| into |out| and returns 1. In
+ * the case of an error it returns 0. */
+static char read_full(int fd, uint8_t *out, size_t len) {
+  ssize_t r;
+
+  while (len > 0) {
+    do {
+      r = read(fd, out, len);
+    } while (r == -1 && errno == EINTR);
+
+    if (r <= 0) {
+      return 0;
+    }
+    out += r;
+    len -= r;
+  }
+
+  return 1;
+}
+
+/* read_from_buffer reads |requested| random bytes from the buffer into |out|,
+ * refilling it if necessary to satisfy the request. */
+static void read_from_buffer(struct rand_buffer *buf,
+                             uint8_t *out, size_t requested) {
+  size_t remaining = BUF_SIZE - buf->used;
+
+  while (requested > remaining) {
+    memcpy(out, &buf->rand[buf->used], remaining);
+    buf->used += remaining;
+    out += remaining;
+    requested -= remaining;
+
+    if (!read_full(urandom_fd, buf->rand, BUF_SIZE)) {
+      abort();
+      return;
+    }
+    buf->used = 0;
+    remaining = BUF_SIZE;
+  }
+
+  memcpy(out, &buf->rand[buf->used], requested);
+  buf->used += requested;
+}
+
+/* CRYPTO_sysrand puts |requested| random bytes into |out|. */
+void CRYPTO_sysrand(uint8_t *out, size_t requested) {
+  if (requested == 0) {
+    return;
+  }
+
+  CRYPTO_once(&once, init_once);
+  if (urandom_buffering && requested < BUF_SIZE) {
+    struct rand_buffer *buf = get_thread_local_buffer();
+    if (buf != NULL) {
+      read_from_buffer(buf, out, requested);
+      return;
+    }
+  }
+
+  if (!read_full(urandom_fd, out, requested)) {
+    abort();
+  }
+}
+
+#endif  /* !OPENSSL_WINDOWS && !BORINGSSL_UNSAFE_FUZZER_MODE */

external/boringssl/crypto/rand/windows.c

@@ -0,0 +1,56 @@
+/* Copyright (c) 2014, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/rand.h>
+
+#if defined(OPENSSL_WINDOWS) && !defined(BORINGSSL_UNSAFE_FUZZER_MODE)
+
+#include <limits.h>
+#include <stdlib.h>
+
+OPENSSL_MSVC_PRAGMA(warning(push, 3))
+
+#include <windows.h>
+
+/* #define needed to link in RtlGenRandom(), a.k.a. SystemFunction036.  See the
+ * "Community Additions" comment on MSDN here:
+ * http://msdn.microsoft.com/en-us/library/windows/desktop/aa387694.aspx */
+#define SystemFunction036 NTAPI SystemFunction036
+#include <ntsecapi.h>
+#undef SystemFunction036
+
+OPENSSL_MSVC_PRAGMA(warning(pop))
+
+#include "internal.h"
+
+
+void RAND_cleanup(void) {
+}
+
+void CRYPTO_sysrand(uint8_t *out, size_t requested) {
+  while (requested > 0) {
+    ULONG output_bytes_this_pass = ULONG_MAX;
+    if (requested < output_bytes_this_pass) {
+      output_bytes_this_pass = requested;
+    }
+    if (RtlGenRandom(out, output_bytes_this_pass) == FALSE) {
+      abort();
+    }
+    requested -= output_bytes_this_pass;
+    out += output_bytes_this_pass;
+  }
+  return;
+}
+
+#endif  /* OPENSSL_WINDOWS && !BORINGSSL_UNSAFE_FUZZER_MODE */