openssl_util.h revision 4a5e2dc747d50c653511c68ccb2cfbfb740bd5a7
1513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// Copyright (c) 2010 The Chromium Authors. All rights reserved. 2513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// Use of this source code is governed by a BSD-style license that can be 3513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// found in the LICENSE file. 4513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 54a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch#ifndef BASE_OPENSSL_UTIL_H_ 64a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch#define BASE_OPENSSL_UTIL_H_ 7513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch#pragma once 8513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 9513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch#include "base/basictypes.h" 104a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch#include "base/tracked.h" 11513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 12513209b27ff55e2841eac0e4120199c23acce758Ben Murdochnamespace base { 13513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 144a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// A helper class that takes care of destroying OpenSSL objects when it goes out 154a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// of scope. 164a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdochtemplate <typename T, void (*destructor)(T*)> 174a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdochclass ScopedOpenSSL { 184a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch public: 194a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch explicit ScopedOpenSSL(T* ptr_) : ptr_(ptr_) { } 204a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch ~ScopedOpenSSL() { if (ptr_) (*destructor)(ptr_); } 214a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 224a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch T* get() const { return ptr_; } 234a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 244a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch private: 254a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch T* ptr_; 264a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch}; 274a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 28513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// Provides a buffer of at least MIN_SIZE bytes, for use when calling OpenSSL's 29513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// SHA256, HMAC, etc functions, adapting the buffer sizing rules to meet those 30513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// of the our base wrapper APIs. 31513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// This allows the library to write directly to the caller's buffer if it is of 32513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// sufficient size, but if not it will write to temporary |min_sized_buffer_| 33513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// of required size and then its content is automatically copied out on 34513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// destruction, with truncation as appropriate. 35513209b27ff55e2841eac0e4120199c23acce758Ben Murdochtemplate<int MIN_SIZE> 36513209b27ff55e2841eac0e4120199c23acce758Ben Murdochclass ScopedOpenSSLSafeSizeBuffer { 37513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch public: 38513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch ScopedOpenSSLSafeSizeBuffer(unsigned char* output, size_t output_len) 39513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch : output_(output), 40513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch output_len_(output_len) { 41513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch } 42513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 43513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch ~ScopedOpenSSLSafeSizeBuffer() { 44513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch if (output_len_ < MIN_SIZE) { 45513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // Copy the temporary buffer out, truncating as needed. 46513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch memcpy(output_, min_sized_buffer_, output_len_); 47513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch } 48513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // else... any writing already happened directly into |output_|. 49513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch } 50513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 51513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch unsigned char* safe_buffer() { 52513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch return output_len_ < MIN_SIZE ? min_sized_buffer_ : output_; 53513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch } 54513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 55513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch private: 56513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // Pointer to the caller's data area and it's associated size, where data 57513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // written via safe_buffer() will [eventually] end up. 58513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch unsigned char* output_; 59513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch size_t output_len_; 60513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 61513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // Temporary buffer writen into in the case where the caller's 62513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // buffer is not of sufficient size. 63513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch unsigned char min_sized_buffer_[MIN_SIZE]; 644a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 654a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch DISALLOW_COPY_AND_ASSIGN(ScopedOpenSSLSafeSizeBuffer); 66513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch}; 67513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 684a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// Initialize OpenSSL if it isn't already initialized. This must be called 694a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// before any other OpenSSL functions. 704a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// This function is thread-safe, and OpenSSL will only ever be initialized once. 714a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// OpenSSL will be properly shut down on program exit. 724a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdochvoid EnsureOpenSSLInit(); 734a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 744a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// Drains the OpenSSL ERR_get_error stack. On a debug build the error codes 754a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// are send to VLOG(1), on a release build they are disregarded. 764a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdochvoid ClearOpenSSLERRStack(); 774a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 78513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch} // namespace base 79513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 804a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch#endif // BASE_OPENSSL_UTIL_H_ 81