1 /*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #ifndef ANDROID_VOLD_KEYBUFFER_H
18 #define ANDROID_VOLD_KEYBUFFER_H
19
20 #include <cstring>
21 #include <memory>
22 #include <vector>
23
24 namespace android {
25 namespace vold {
26
27 /**
28 * Variant of memset() that should never be optimized away. Borrowed from keymaster code.
29 */
30 #ifdef __clang__
31 #define OPTNONE __attribute__((optnone))
32 #else // not __clang__
33 #define OPTNONE __attribute__((optimize("O0")))
34 #endif // not __clang__
memset_s(void * s,int c,size_t n)35 inline OPTNONE void* memset_s(void* s, int c, size_t n) {
36 if (!s) return s;
37 return memset(s, c, n);
38 }
39 #undef OPTNONE
40
41 // Allocator that delegates useful work to standard one but zeroes data before deallocating.
42 class ZeroingAllocator : public std::allocator<char> {
43 public:
deallocate(pointer p,size_type n)44 void deallocate(pointer p, size_type n) {
45 memset_s(p, 0, n);
46 std::allocator<char>::deallocate(p, n);
47 }
48 };
49
50 // Char vector that zeroes memory when deallocating.
51 using KeyBuffer = std::vector<char, ZeroingAllocator>;
52
53 // Convenience methods to concatenate key buffers.
54 KeyBuffer operator+(KeyBuffer&& lhs, const KeyBuffer& rhs);
55 KeyBuffer operator+(KeyBuffer&& lhs, const char* rhs);
56
57 } // namespace vold
58 } // namespace android
59
60 #endif
61