base/rand_util_nacl.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/rand_util.h"
   6
   7 #include "base/basictypes.h"
   8 #include "base/lazy_instance.h"
   9 #include "base/logging.h"
  10 #include "native_client/src/untrusted/irt/irt.h"
  11
  12 namespace {
  13
  14 class NaclRandom {
  15  public:
  16   NaclRandom() {
  17     const size_t result =
  18         nacl_interface_query(NACL_IRT_RANDOM_v0_1, &random_, sizeof(random_));
  19     CHECK_EQ(result, sizeof(random_));
  20   }
  21
  22   ~NaclRandom() {}
  23
  24   void GetRandomBytes(void* output, size_t num_bytes) {
  25     char* output_ptr = static_cast<char*>(output);
  26     while (num_bytes > 0) {
  27       size_t nread;
  28       const int error = random_.get_random_bytes(output_ptr, num_bytes, &nread);
  29       CHECK_EQ(error, 0);
  30       CHECK_LE(nread, num_bytes);
  31       output_ptr += nread;
  32       num_bytes -= nread;
  33     }
  34   }
  35
  36  private:
  37   nacl_irt_random random_;
  38 };
  39
  40 base::LazyInstance<NaclRandom>::Leaky g_nacl_random = LAZY_INSTANCE_INITIALIZER;
  41
  42 }  // namespace
  43
  44 namespace base {
  45
  46 // NOTE: This function must be cryptographically secure. http://crbug.com/140076
  47 uint64 RandUint64() {
  48   uint64 result;
  49   g_nacl_random.Pointer()->GetRandomBytes(&result, sizeof(result));
  50   return result;
  51 }
  52
  53 void RandBytes(void* output, size_t output_length) {
  54   g_nacl_random.Pointer()->GetRandomBytes(output, output_length);
  55 }
  56
  57 }  // namespace base