openssl_util.h revision 201ade2fbba22bfb27ae029f4d23fca6ded109a0
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: 19201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch ScopedOpenSSL() : ptr_(NULL) { } 20201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch explicit ScopedOpenSSL(T* ptr) : ptr_(ptr) { } 214a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch ~ScopedOpenSSL() { if (ptr_) (*destructor)(ptr_); } 224a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 234a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch T* get() const { return ptr_; } 24201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch void reset(T* ptr) { 25201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch if (ptr != ptr_) { 26201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch if (ptr_) (*destructor)(ptr_); 27201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch ptr_ = ptr; 28201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch } 29201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch } 304a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 314a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch private: 324a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch T* ptr_; 33201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch 34201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch DISALLOW_COPY_AND_ASSIGN(ScopedOpenSSL); 354a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch}; 364a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 37513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// Provides a buffer of at least MIN_SIZE bytes, for use when calling OpenSSL's 38513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// SHA256, HMAC, etc functions, adapting the buffer sizing rules to meet those 39513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// of the our base wrapper APIs. 40513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// This allows the library to write directly to the caller's buffer if it is of 41513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// sufficient size, but if not it will write to temporary |min_sized_buffer_| 42513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// of required size and then its content is automatically copied out on 43513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch// destruction, with truncation as appropriate. 44513209b27ff55e2841eac0e4120199c23acce758Ben Murdochtemplate<int MIN_SIZE> 45513209b27ff55e2841eac0e4120199c23acce758Ben Murdochclass ScopedOpenSSLSafeSizeBuffer { 46513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch public: 47513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch ScopedOpenSSLSafeSizeBuffer(unsigned char* output, size_t output_len) 48513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch : output_(output), 49513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch output_len_(output_len) { 50513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch } 51513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 52513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch ~ScopedOpenSSLSafeSizeBuffer() { 53513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch if (output_len_ < MIN_SIZE) { 54513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // Copy the temporary buffer out, truncating as needed. 55513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch memcpy(output_, min_sized_buffer_, output_len_); 56513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch } 57513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // else... any writing already happened directly into |output_|. 58513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch } 59513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 60513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch unsigned char* safe_buffer() { 61513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch return output_len_ < MIN_SIZE ? min_sized_buffer_ : output_; 62513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch } 63513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 64513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch private: 65513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // Pointer to the caller's data area and it's associated size, where data 66513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // written via safe_buffer() will [eventually] end up. 67513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch unsigned char* output_; 68513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch size_t output_len_; 69513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 70513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // Temporary buffer writen into in the case where the caller's 71513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch // buffer is not of sufficient size. 72513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch unsigned char min_sized_buffer_[MIN_SIZE]; 734a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 744a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch DISALLOW_COPY_AND_ASSIGN(ScopedOpenSSLSafeSizeBuffer); 75513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch}; 76513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 774a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// Initialize OpenSSL if it isn't already initialized. This must be called 784a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// before any other OpenSSL functions. 794a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// This function is thread-safe, and OpenSSL will only ever be initialized once. 804a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// OpenSSL will be properly shut down on program exit. 814a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdochvoid EnsureOpenSSLInit(); 824a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 834a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch// Drains the OpenSSL ERR_get_error stack. On a debug build the error codes 84201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch// are send to VLOG(1), on a release build they are disregarded. In most 85201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch// cases you should pass FROM_HERE as the |location|. 86201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdochvoid ClearOpenSSLERRStack(const tracked_objects::Location& location); 87201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch 88201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch// Place an instance of this class on the call stack to automatically clear 89201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch// the OpenSSL error stack on function exit. 90201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdochclass OpenSSLErrStackTracer { 91201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch public: 92201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch // Pass FROM_HERE as |location|, to help track the source of OpenSSL error 93201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch // messages. Note any diagnostic emitted will be tagged with the location of 94201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch // the constructor call as it's not possible to trace a destructor's callsite. 95201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch explicit OpenSSLErrStackTracer(const tracked_objects::Location& location) 96201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch : location_(location) { 97201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch EnsureOpenSSLInit(); 98201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch } 99201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch ~OpenSSLErrStackTracer() { 100201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch ClearOpenSSLERRStack(location_); 101201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch } 102201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch 103201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch private: 104201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch const tracked_objects::Location location_; 105201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch 106201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch DISALLOW_IMPLICIT_CONSTRUCTORS(OpenSSLErrStackTracer); 107201ade2fbba22bfb27ae029f4d23fca6ded109a0Ben Murdoch}; 1084a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch 109513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch} // namespace base 110513209b27ff55e2841eac0e4120199c23acce758Ben Murdoch 1114a5e2dc747d50c653511c68ccb2cfbfb740bd5a7Ben Murdoch#endif // BASE_OPENSSL_UTIL_H_ 112