crypto/openssl_util.cc

   1 // Copyright (c) 2011 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 "crypto/openssl_util.h"
   6
   7 #include <openssl/err.h>
   8 #include <openssl/ssl.h>
   9
  10 #include "base/logging.h"
  11 #include "base/memory/scoped_vector.h"
  12 #include "base/memory/singleton.h"
  13 #include "base/string_piece.h"
  14 #include "base/synchronization/lock.h"
  15
  16 namespace crypto {
  17
  18 namespace {
  19
  20 unsigned long CurrentThreadId() {
  21   return static_cast<unsigned long>(base::PlatformThread::CurrentId());
  22 }
  23
  24 // Singleton for initializing and cleaning up the OpenSSL library.
  25 class OpenSSLInitSingleton {
  26  public:
  27   static OpenSSLInitSingleton* GetInstance() {
  28     // We allow the SSL environment to leak for multiple reasons:
  29     //   -  it is used from a non-joinable worker thread that is not stopped on
  30     //      shutdown, hence may still be using OpenSSL library after the AtExit
  31     //      runner has completed.
  32     //   -  There are other OpenSSL related singletons (e.g. the client socket
  33     //      context) who's cleanup depends on the global environment here, but
  34     //      we can't control the order the AtExit handlers will run in so
  35     //      allowing the global environment to leak at least ensures it is
  36     //      available for those other singletons to reliably cleanup.
  37     return Singleton<OpenSSLInitSingleton,
  38                LeakySingletonTraits<OpenSSLInitSingleton> >::get();
  39   }
  40  private:
  41   friend struct DefaultSingletonTraits<OpenSSLInitSingleton>;
  42   OpenSSLInitSingleton() {
  43     SSL_load_error_strings();
  44     SSL_library_init();
  45     OpenSSL_add_all_algorithms();
  46     int num_locks = CRYPTO_num_locks();
  47     locks_.reserve(num_locks);
  48     for (int i = 0; i < num_locks; ++i)
  49       locks_.push_back(new base::Lock());
  50     CRYPTO_set_locking_callback(LockingCallback);
  51     CRYPTO_set_id_callback(CurrentThreadId);
  52   }
  53
  54   ~OpenSSLInitSingleton() {
  55     CRYPTO_set_locking_callback(NULL);
  56     EVP_cleanup();
  57     ERR_free_strings();
  58   }
  59
  60   static void LockingCallback(int mode, int n, const char* file, int line) {
  61     OpenSSLInitSingleton::GetInstance()->OnLockingCallback(mode, n, file, line);
  62   }
  63
  64   void OnLockingCallback(int mode, int n, const char* file, int line) {
  65     CHECK_LT(static_cast<size_t>(n), locks_.size());
  66     if (mode & CRYPTO_LOCK)
  67       locks_[n]->Acquire();
  68     else
  69       locks_[n]->Release();
  70   }
  71
  72   // These locks are used and managed by OpenSSL via LockingCallback().
  73   ScopedVector<base::Lock> locks_;
  74
  75   DISALLOW_COPY_AND_ASSIGN(OpenSSLInitSingleton);
  76 };
  77
  78 // Callback routine for OpenSSL to print error messages. |str| is a
  79 // NULL-terminated string of length |len| containing diagnostic information
  80 // such as the library, function and reason for the error, the file and line
  81 // where the error originated, plus potentially any context-specific
  82 // information about the error. |context| contains a pointer to user-supplied
  83 // data, which is currently unused.
  84 // If this callback returns a value <= 0, OpenSSL will stop processing the
  85 // error queue and return, otherwise it will continue calling this function
  86 // until all errors have been removed from the queue.
  87 int OpenSSLErrorCallback(const char* str, size_t len, void* context) {
  88   DVLOG(1) << "\t" << base::StringPiece(str, len);
  89   return 1;
  90 }
  91
  92 }  // namespace
  93
  94 void EnsureOpenSSLInit() {
  95   (void)OpenSSLInitSingleton::GetInstance();
  96 }
  97
  98 void ClearOpenSSLERRStack(const tracked_objects::Location& location) {
  99   if (logging::DEBUG_MODE && VLOG_IS_ON(1)) {
 100     int error_num = ERR_peek_error();
 101     if (error_num == 0)
 102       return;
 103
 104     std::string message;
 105     location.Write(true, true, &message);
 106     DVLOG(1) << "OpenSSL ERR_get_error stack from " << message;
 107     ERR_print_errors_cb(&OpenSSLErrorCallback, NULL);
 108   } else {
 109     ERR_clear_error();
 110   }
 111 }
 112
 113 }  // namespace crypto