1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
|
// Copyright (c) 2010 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 BASE_OPENSSL_UTIL_H_
#define BASE_OPENSSL_UTIL_H_
#pragma once
#include "base/basictypes.h"
#include "base/tracked.h"
namespace base {
// A helper class that takes care of destroying OpenSSL objects when it goes out
// of scope.
template <typename T, void (*destructor)(T*)>
class ScopedOpenSSL {
public:
explicit ScopedOpenSSL(T* ptr_) : ptr_(ptr_) { }
~ScopedOpenSSL() { if (ptr_) (*destructor)(ptr_); }
T* get() const { return ptr_; }
private:
T* ptr_;
};
// 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 the 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() {
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_;
}
private:
// Pointer to the caller's data area and it's associated size, where data
// written via safe_buffer() will [eventually] end up.
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];
DISALLOW_COPY_AND_ASSIGN(ScopedOpenSSLSafeSizeBuffer);
};
// Initialize OpenSSL if it isn't already initialized. This must be called
// before any other OpenSSL functions.
// This function is thread-safe, and OpenSSL will only ever be initialized once.
// OpenSSL will be properly shut down on program exit.
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.
void ClearOpenSSLERRStack();
} // namespace base
#endif // BASE_OPENSSL_UTIL_H_
|