OLD | NEW |
(Empty) | |
| 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 #ifndef CRYPTO_OPENSSL_UTIL_H_ |
| 6 #define CRYPTO_OPENSSL_UTIL_H_ |
| 7 #pragma once |
| 8 |
| 9 #include "base/basictypes.h" |
| 10 #include "base/tracked.h" |
| 11 |
| 12 namespace crypto { |
| 13 |
| 14 // A helper class that takes care of destroying OpenSSL objects when it goes out |
| 15 // of scope. |
| 16 template <typename T, void (*destructor)(T*)> |
| 17 class ScopedOpenSSL { |
| 18 public: |
| 19 ScopedOpenSSL() : ptr_(NULL) { } |
| 20 explicit ScopedOpenSSL(T* ptr) : ptr_(ptr) { } |
| 21 ~ScopedOpenSSL() { |
| 22 reset(NULL); |
| 23 } |
| 24 |
| 25 T* get() const { return ptr_; } |
| 26 void reset(T* ptr) { |
| 27 if (ptr != ptr_) { |
| 28 if (ptr_) (*destructor)(ptr_); |
| 29 ptr_ = ptr; |
| 30 } |
| 31 } |
| 32 |
| 33 private: |
| 34 T* ptr_; |
| 35 |
| 36 DISALLOW_COPY_AND_ASSIGN(ScopedOpenSSL); |
| 37 }; |
| 38 |
| 39 // Provides a buffer of at least MIN_SIZE bytes, for use when calling OpenSSL's |
| 40 // SHA256, HMAC, etc functions, adapting the buffer sizing rules to meet those |
| 41 // of the our base wrapper APIs. |
| 42 // This allows the library to write directly to the caller's buffer if it is of |
| 43 // sufficient size, but if not it will write to temporary |min_sized_buffer_| |
| 44 // of required size and then its content is automatically copied out on |
| 45 // destruction, with truncation as appropriate. |
| 46 template<int MIN_SIZE> |
| 47 class ScopedOpenSSLSafeSizeBuffer { |
| 48 public: |
| 49 ScopedOpenSSLSafeSizeBuffer(unsigned char* output, size_t output_len) |
| 50 : output_(output), |
| 51 output_len_(output_len) { |
| 52 } |
| 53 |
| 54 ~ScopedOpenSSLSafeSizeBuffer() { |
| 55 if (output_len_ < MIN_SIZE) { |
| 56 // Copy the temporary buffer out, truncating as needed. |
| 57 memcpy(output_, min_sized_buffer_, output_len_); |
| 58 } |
| 59 // else... any writing already happened directly into |output_|. |
| 60 } |
| 61 |
| 62 unsigned char* safe_buffer() { |
| 63 return output_len_ < MIN_SIZE ? min_sized_buffer_ : output_; |
| 64 } |
| 65 |
| 66 private: |
| 67 // Pointer to the caller's data area and it's associated size, where data |
| 68 // written via safe_buffer() will [eventually] end up. |
| 69 unsigned char* output_; |
| 70 size_t output_len_; |
| 71 |
| 72 // Temporary buffer writen into in the case where the caller's |
| 73 // buffer is not of sufficient size. |
| 74 unsigned char min_sized_buffer_[MIN_SIZE]; |
| 75 |
| 76 DISALLOW_COPY_AND_ASSIGN(ScopedOpenSSLSafeSizeBuffer); |
| 77 }; |
| 78 |
| 79 // Initialize OpenSSL if it isn't already initialized. This must be called |
| 80 // before any other OpenSSL functions. |
| 81 // This function is thread-safe, and OpenSSL will only ever be initialized once. |
| 82 // OpenSSL will be properly shut down on program exit. |
| 83 void EnsureOpenSSLInit(); |
| 84 |
| 85 // Drains the OpenSSL ERR_get_error stack. On a debug build the error codes |
| 86 // are send to VLOG(1), on a release build they are disregarded. In most |
| 87 // cases you should pass FROM_HERE as the |location|. |
| 88 void ClearOpenSSLERRStack(const tracked_objects::Location& location); |
| 89 |
| 90 // Place an instance of this class on the call stack to automatically clear |
| 91 // the OpenSSL error stack on function exit. |
| 92 class OpenSSLErrStackTracer { |
| 93 public: |
| 94 // Pass FROM_HERE as |location|, to help track the source of OpenSSL error |
| 95 // messages. Note any diagnostic emitted will be tagged with the location of |
| 96 // the constructor call as it's not possible to trace a destructor's callsite. |
| 97 explicit OpenSSLErrStackTracer(const tracked_objects::Location& location) |
| 98 : location_(location) { |
| 99 EnsureOpenSSLInit(); |
| 100 } |
| 101 ~OpenSSLErrStackTracer() { |
| 102 ClearOpenSSLERRStack(location_); |
| 103 } |
| 104 |
| 105 private: |
| 106 const tracked_objects::Location location_; |
| 107 |
| 108 DISALLOW_IMPLICIT_CONSTRUCTORS(OpenSSLErrStackTracer); |
| 109 }; |
| 110 |
| 111 } // namespace crypto |
| 112 |
| 113 #endif // CRYPTO_OPENSSL_UTIL_H_ |
OLD | NEW |