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 <string.h> 21 #include <memory> 22 #include <type_traits> 23 #include <vector> 24 25 namespace android { 26 namespace vold { 27 28 // Allocator that delegates useful work to standard one but zeroes data before deallocating. 29 class ZeroingAllocator : public std::allocator<char> { 30 public: deallocate(value_type * p,size_type n)31 void deallocate(value_type* p, size_type n) { 32 memset_explicit(p, 0, n); 33 std::allocator<char>::deallocate(p, n); 34 } 35 36 template <class Other> 37 struct rebind { 38 static_assert(std::is_same_v<char, Other>, "ZeroingAllocator is only defined for char"); 39 using other = ZeroingAllocator; 40 }; 41 }; 42 43 // Char vector that zeroes memory when deallocating. 44 using KeyBuffer = std::vector<char, ZeroingAllocator>; 45 46 // Convenience methods to concatenate key buffers. 47 KeyBuffer operator+(KeyBuffer&& lhs, const KeyBuffer& rhs); 48 KeyBuffer operator+(KeyBuffer&& lhs, const char* rhs); 49 50 } // namespace vold 51 } // namespace android 52 53 #endif 54