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      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
    114