henrike@webrtc.org | f7795df | 2014-05-13 18:00:26 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2004 The WebRTC Project Authors. All rights reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | // @file Contains utility classes that make it easier to use SecBuffers |
| 12 | |
| 13 | #ifndef WEBRTC_BASE_SEC_BUFFER_H__ |
| 14 | #define WEBRTC_BASE_SEC_BUFFER_H__ |
| 15 | |
| 16 | namespace rtc { |
| 17 | |
| 18 | // A base class for CSecBuffer<T>. Contains |
| 19 | // all implementation that does not require |
| 20 | // template arguments. |
| 21 | class CSecBufferBase : public SecBuffer { |
| 22 | public: |
| 23 | CSecBufferBase() { |
| 24 | Clear(); |
| 25 | } |
| 26 | |
| 27 | // Uses the SSPI to free a pointer, must be |
| 28 | // used for buffers returned from SSPI APIs. |
| 29 | static void FreeSSPI(void *ptr) { |
| 30 | if ( ptr ) { |
| 31 | SECURITY_STATUS status; |
| 32 | status = ::FreeContextBuffer(ptr); |
| 33 | ASSERT(SEC_E_OK == status); // "Freeing context buffer" |
| 34 | } |
| 35 | } |
| 36 | |
| 37 | // Deletes a buffer with operator delete |
| 38 | static void FreeDelete(void *ptr) { |
| 39 | delete [] reinterpret_cast<char*>(ptr); |
| 40 | } |
| 41 | |
| 42 | // A noop delete, for buffers over other |
| 43 | // people's memory |
| 44 | static void FreeNone(void *ptr) { |
| 45 | } |
| 46 | |
| 47 | protected: |
| 48 | // Clears the buffer to EMPTY & NULL |
| 49 | void Clear() { |
| 50 | this->BufferType = SECBUFFER_EMPTY; |
| 51 | this->cbBuffer = 0; |
| 52 | this->pvBuffer = NULL; |
| 53 | } |
| 54 | }; |
| 55 | |
| 56 | // Wrapper class for SecBuffer to take care |
| 57 | // of initialization and destruction. |
| 58 | template <void (*pfnFreeBuffer)(void *ptr)> |
| 59 | class CSecBuffer: public CSecBufferBase { |
| 60 | public: |
| 61 | // Initializes buffer to empty & NULL |
| 62 | CSecBuffer() { |
| 63 | } |
| 64 | |
| 65 | // Frees any allocated memory |
| 66 | ~CSecBuffer() { |
| 67 | Release(); |
| 68 | } |
| 69 | |
| 70 | // Frees the buffer appropriately, and re-nulls |
| 71 | void Release() { |
| 72 | pfnFreeBuffer(this->pvBuffer); |
| 73 | Clear(); |
| 74 | } |
| 75 | |
| 76 | private: |
| 77 | // A placeholder function for compile-time asserts on the class |
| 78 | void CompileAsserts() { |
| 79 | // never invoked... |
| 80 | assert(false); // _T("Notreached") |
| 81 | |
| 82 | // This class must not extend the size of SecBuffer, since |
| 83 | // we use arrays of CSecBuffer in CSecBufferBundle below |
| 84 | cassert(sizeof(CSecBuffer<SSPIFree> == sizeof(SecBuffer))); |
| 85 | } |
| 86 | }; |
| 87 | |
| 88 | // Contains all generic implementation for the |
| 89 | // SecBufferBundle class |
| 90 | class SecBufferBundleBase { |
| 91 | public: |
| 92 | }; |
| 93 | |
| 94 | // A template class that bundles a SecBufferDesc with |
| 95 | // one or more SecBuffers for convenience. Can take |
| 96 | // care of deallocating buffers appropriately, as indicated |
| 97 | // by pfnFreeBuffer function. |
| 98 | // By default does no deallocation. |
| 99 | template <int num_buffers, |
| 100 | void (*pfnFreeBuffer)(void *ptr) = CSecBufferBase::FreeNone> |
| 101 | class CSecBufferBundle : public SecBufferBundleBase { |
| 102 | public: |
| 103 | // Constructs a security buffer bundle with num_buffers |
| 104 | // buffers, all of which are empty and nulled. |
| 105 | CSecBufferBundle() { |
| 106 | desc_.ulVersion = SECBUFFER_VERSION; |
| 107 | desc_.cBuffers = num_buffers; |
| 108 | desc_.pBuffers = buffers_; |
| 109 | } |
| 110 | |
| 111 | // Frees all currently used buffers. |
| 112 | ~CSecBufferBundle() { |
| 113 | Release(); |
| 114 | } |
| 115 | |
| 116 | // Accessor for the descriptor |
| 117 | PSecBufferDesc desc() { |
| 118 | return &desc_; |
| 119 | } |
| 120 | |
| 121 | // Accessor for the descriptor |
| 122 | const PSecBufferDesc desc() const { |
| 123 | return &desc_; |
| 124 | } |
| 125 | |
| 126 | // returns the i-th security buffer |
| 127 | SecBuffer &operator[] (size_t num) { |
| 128 | ASSERT(num < num_buffers); // "Buffer index out of bounds" |
| 129 | return buffers_[num]; |
| 130 | } |
| 131 | |
| 132 | // returns the i-th security buffer |
| 133 | const SecBuffer &operator[] (size_t num) const { |
| 134 | ASSERT(num < num_buffers); // "Buffer index out of bounds" |
| 135 | return buffers_[num]; |
| 136 | } |
| 137 | |
| 138 | // Frees all non-NULL security buffers, |
| 139 | // using the deallocation function |
| 140 | void Release() { |
| 141 | for ( size_t i = 0; i < num_buffers; ++i ) { |
| 142 | buffers_[i].Release(); |
| 143 | } |
| 144 | } |
| 145 | |
| 146 | private: |
| 147 | // Our descriptor |
| 148 | SecBufferDesc desc_; |
| 149 | // Our bundled buffers, each takes care of its own |
| 150 | // initialization and destruction |
| 151 | CSecBuffer<pfnFreeBuffer> buffers_[num_buffers]; |
| 152 | }; |
| 153 | |
| 154 | } // namespace rtc |
| 155 | |
| 156 | #endif // WEBRTC_BASE_SEC_BUFFER_H__ |