src/support/allocators/secure.h

   1 // Copyright (c) 2009-2010 Satoshi Nakamoto
   2 // Copyright (c) 2009-2016 The Bitcoin Core developers
   3 // Distributed under the MIT software license, see the accompanying
   4 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5
   6 #ifndef BITCOIN_SUPPORT_ALLOCATORS_SECURE_H
   7 #define BITCOIN_SUPPORT_ALLOCATORS_SECURE_H
   8
   9 #include "support/lockedpool.h"
  10 #include "support/cleanse.h"
  11
  12 #include <string>
  13
  14 //
  15 // Allocator that locks its contents from being paged
  16 // out of memory and clears its contents before deletion.
  17 //
  18 template <typename T>
  19 struct secure_allocator : public std::allocator<T> {
  20     // MSVC8 default copy constructor is broken
  21     typedef std::allocator<T> base;
  22     typedef typename base::size_type size_type;
  23     typedef typename base::difference_type difference_type;
  24     typedef typename base::pointer pointer;
  25     typedef typename base::const_pointer const_pointer;
  26     typedef typename base::reference reference;
  27     typedef typename base::const_reference const_reference;
  28     typedef typename base::value_type value_type;
  29     secure_allocator() noexcept {}
  30     secure_allocator(const secure_allocator& a) noexcept : base(a) {}
  31     template <typename U>
  32     secure_allocator(const secure_allocator<U>& a) noexcept : base(a)
  33     {
  34     }
  35     ~secure_allocator() noexcept {}
  36     template <typename _Other>
  37     struct rebind {
  38         typedef secure_allocator<_Other> other;
  39     };
  40
  41     T* allocate(std::size_t n, const void* hint = 0)
  42     {
  43         return static_cast<T*>(LockedPoolManager::Instance().alloc(sizeof(T) * n));
  44     }
  45
  46     void deallocate(T* p, std::size_t n)
  47     {
  48         if (p != nullptr) {
  49             memory_cleanse(p, sizeof(T) * n);
  50         }
  51         LockedPoolManager::Instance().free(p);
  52     }
  53 };
  54
  55 // This is exactly like std::string, but with a custom allocator.
  56 typedef std::basic_string<char, std::char_traits<char>, secure_allocator<char> > SecureString;
  57
  58 #endif // BITCOIN_SUPPORT_ALLOCATORS_SECURE_H