OSX/libsecurity_utilities/lib/devrandom.cpp

   1 /*
   2  * Copyright (c) 2000-2004,2011,2014 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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  18  * Please see the License for the specific language governing rights and
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  22  */
  23
  24
  25 //
  26 // devrandom - RNG operations based on /dev/random
  27 //
  28 #include <security_utilities/devrandom.h>
  29 #include <security_utilities/logging.h>
  30 #include <CommonCrypto/CommonRandomSPI.h>
  31
  32 using namespace UnixPlusPlus;
  33
  34
  35 namespace Security {
  36
  37
  38 //
  39 // The common (shared) open file descriptor to /dev/random
  40 //
  41 ModuleNexus<DevRandomGenerator::Writable> DevRandomGenerator::mWriter;
  42
  43
  44 //
  45 // In the current implementation, opening the file descriptor is deferred.
  46 //
  47 DevRandomGenerator::DevRandomGenerator(bool writable)
  48 {
  49 }
  50
  51
  52 //
  53 // Standard generate (directly from /dev/random)
  54 //
  55 void DevRandomGenerator::random(void *data, size_t length)
  56 {
  57     if (CCRandomCopyBytes(kCCRandomDefault, data, length)) {
  58         Syslog::error("DevRandomGenerator: failed to generate random");
  59         UnixError::throwMe(EIO);
  60     }
  61 }
  62
  63
  64 //
  65 // If you opened for writing, you add entropy to the global pool here
  66 //
  67 void DevRandomGenerator::addEntropy(const void *data, size_t length)
  68 {
  69     if (mWriter().write(data, length) != length)
  70                 UnixError::throwMe(EIO);        // short write (shouldn't happen)
  71 }
  72
  73
  74 }       // end namespace Security