1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798 |
- // Copyright (c) 2012 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #ifndef CRYPTO_OPENSSL_UTIL_H_
- #define CRYPTO_OPENSSL_UTIL_H_
- #include <stddef.h>
- #include <string.h>
- #include "base/location.h"
- #include "base/memory/raw_ptr.h"
- #include "crypto/crypto_export.h"
- namespace crypto {
- // Provides a buffer of at least MIN_SIZE bytes, for use when calling OpenSSL's
- // SHA256, HMAC, etc functions, adapting the buffer sizing rules to meet those
- // of our base wrapper APIs.
- // This allows the library to write directly to the caller's buffer if it is of
- // sufficient size, but if not it will write to temporary |min_sized_buffer_|
- // of required size and then its content is automatically copied out on
- // destruction, with truncation as appropriate.
- template<int MIN_SIZE>
- class ScopedOpenSSLSafeSizeBuffer {
- public:
- ScopedOpenSSLSafeSizeBuffer(unsigned char* output, size_t output_len)
- : output_(output),
- output_len_(output_len) {
- }
- ScopedOpenSSLSafeSizeBuffer(const ScopedOpenSSLSafeSizeBuffer&) = delete;
- ScopedOpenSSLSafeSizeBuffer& operator=(const ScopedOpenSSLSafeSizeBuffer&) =
- delete;
- ~ScopedOpenSSLSafeSizeBuffer() {
- if (output_len_ < MIN_SIZE) {
- // Copy the temporary buffer out, truncating as needed.
- memcpy(output_, min_sized_buffer_, output_len_);
- }
- // else... any writing already happened directly into |output_|.
- }
- unsigned char* safe_buffer() {
- return output_len_ < MIN_SIZE ? min_sized_buffer_ : output_.get();
- }
- private:
- // Pointer to the caller's data area and its associated size, where data
- // written via safe_buffer() will [eventually] end up.
- raw_ptr<unsigned char> output_;
- size_t output_len_;
- // Temporary buffer writen into in the case where the caller's
- // buffer is not of sufficient size.
- unsigned char min_sized_buffer_[MIN_SIZE];
- };
- // Initialize OpenSSL if it isn't already initialized. This must be called
- // before any other OpenSSL functions though it is safe and cheap to call this
- // multiple times.
- // This function is thread-safe, and OpenSSL will only ever be initialized once.
- // OpenSSL will be properly shut down on program exit.
- CRYPTO_EXPORT void EnsureOpenSSLInit();
- // Drains the OpenSSL ERR_get_error stack. On a debug build the error codes
- // are send to VLOG(1), on a release build they are disregarded. In most
- // cases you should pass FROM_HERE as the |location|.
- CRYPTO_EXPORT void ClearOpenSSLERRStack(const base::Location& location);
- // Place an instance of this class on the call stack to automatically clear
- // the OpenSSL error stack on function exit.
- class OpenSSLErrStackTracer {
- public:
- OpenSSLErrStackTracer() = delete;
- // Pass FROM_HERE as |location|, to help track the source of OpenSSL error
- // messages. Note any diagnostic emitted will be tagged with the location of
- // the constructor call as it's not possible to trace a destructor's callsite.
- explicit OpenSSLErrStackTracer(const base::Location& location)
- : location_(location) {
- EnsureOpenSSLInit();
- }
- OpenSSLErrStackTracer(const OpenSSLErrStackTracer&) = delete;
- OpenSSLErrStackTracer& operator=(const OpenSSLErrStackTracer&) = delete;
- ~OpenSSLErrStackTracer() {
- ClearOpenSSLERRStack(location_);
- }
- private:
- const base::Location location_;
- };
- } // namespace crypto
- #endif // CRYPTO_OPENSSL_UTIL_H_
|