secure.h raw

   1  // Copyright (c) 2009-2010 Satoshi Nakamoto
   2  // Copyright (c) 2009-present The Limenka 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 LIMENKA_SUPPORT_ALLOCATORS_SECURE_H
   7  #define LIMENKA_SUPPORT_ALLOCATORS_SECURE_H
   8  
   9  #include <support/lockedpool.h>
  10  #include <support/cleanse.h>
  11  
  12  #include <memory>
  13  #include <string>
  14  
  15  //
  16  // Allocator that locks its contents from being paged
  17  // out of memory and clears its contents before deletion.
  18  //
  19  template <typename T>
  20  struct secure_allocator {
  21      using value_type = T;
  22  
  23      secure_allocator() = default;
  24      template <typename U>
  25      secure_allocator(const secure_allocator<U>&) noexcept {}
  26  
  27      T* allocate(std::size_t n)
  28      {
  29          T* allocation = static_cast<T*>(LockedPoolManager::Instance().alloc(sizeof(T) * n));
  30          if (!allocation) {
  31              throw std::bad_alloc();
  32          }
  33          return allocation;
  34      }
  35  
  36      void deallocate(T* p, std::size_t n)
  37      {
  38          if (p != nullptr) {
  39              memory_cleanse(p, sizeof(T) * n);
  40          }
  41          LockedPoolManager::Instance().free(p);
  42      }
  43  
  44      template <typename U>
  45      friend bool operator==(const secure_allocator&, const secure_allocator<U>&) noexcept
  46      {
  47          return true;
  48      }
  49      template <typename U>
  50      friend bool operator!=(const secure_allocator&, const secure_allocator<U>&) noexcept
  51      {
  52          return false;
  53      }
  54  };
  55  
  56  // This is exactly like std::string, but with a custom allocator.
  57  // TODO: Consider finding a way to make incoming RPC request.params[i] mlock()ed as well
  58  typedef std::basic_string<char, std::char_traits<char>, secure_allocator<char> > SecureString;
  59  
  60  template<typename T>
  61  struct SecureUniqueDeleter {
  62      void operator()(T* t) noexcept {
  63          secure_allocator<T>().deallocate(t, 1);
  64      }
  65  };
  66  
  67  template<typename T>
  68  using secure_unique_ptr = std::unique_ptr<T, SecureUniqueDeleter<T>>;
  69  
  70  template<typename T, typename... Args>
  71  secure_unique_ptr<T> make_secure_unique(Args&&... as)
  72  {
  73      T* p = secure_allocator<T>().allocate(1);
  74  
  75      // initialize in place, and return as secure_unique_ptr
  76      try {
  77          return secure_unique_ptr<T>(new (p) T(std::forward<Args>(as)...));
  78      } catch (...) {
  79          secure_allocator<T>().deallocate(p, 1);
  80          throw;
  81      }
  82  }
  83  
  84  #endif // LIMENKA_SUPPORT_ALLOCATORS_SECURE_H
  85