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/*
* Copyright (c) 2010 SURFnet bv
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
* IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*****************************************************************************
SecureAllocator.h
Implements a template class for a secure C++ allocator. The allocator will
zero all the memory it allocates before releasing it to ensure that the
data stored in the memory is destroyed properly to minimise the risk of
obtaining sensitive data from memory
*****************************************************************************/
#ifndef _SOFTHSM_V2_SECUREALLOCATOR_H
#define _SOFTHSM_V2_SECUREALLOCATOR_H
#include <limits>
#include <stdlib.h>
#include <string.h>
#if defined(SENSITIVE_NON_PAGED) && !defined(_WIN32)
#include <sys/mman.h>
#endif // SENSITIVE_NON_PAGED
#include "config.h"
#include "log.h"
#include "SecureMemoryRegistry.h"
template<class T> class SecureAllocator
{
public:
// Member types
typedef T value_type;
typedef T* pointer;
typedef T& reference;
typedef const T* const_pointer;
typedef const T& const_reference;
typedef size_t size_type;
typedef ptrdiff_t difference_type;
// Rebind to another type
template<class U> struct rebind
{
typedef SecureAllocator<U> other;
};
// Constructor
inline SecureAllocator() { }
inline SecureAllocator(const SecureAllocator&) { }
template<class U> SecureAllocator(const SecureAllocator<U>&) { }
// Destructor
inline virtual ~SecureAllocator() { }
// Return the maximum allocation size
size_type max_size() const
{
return std::numeric_limits<std::size_t>::max() / sizeof(T);
}
// Return the address of values
inline pointer address(reference value) const
{
return &value;
}
inline const_pointer address(const_reference value) const
{
return &value;
}
// Allocate n elements of type T
inline pointer allocate(size_type n, const void* = NULL)
{
#ifdef SENSITIVE_NON_PAGED
// Allocate memory on a page boundary
#ifndef _WIN32
pointer r = (pointer) valloc(n * sizeof(T));
#else
pointer r = (pointer) VirtualAlloc(NULL, n * sizeof(T), MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
#endif
if (r == NULL)
{
ERROR_MSG("Out of memory");
return NULL;
}
// Lock the memory so it doesn't get swapped out
#ifndef _WIN32
if (mlock((const void*) r, n * sizeof(T)) != 0)
#else
if (VirtualLock((const void*) r, n * sizeof(T)) == 0)
#endif
{
ERROR_MSG("Could not allocate non-paged memory for secure storage");
// Hmmm... best to not return any allocated space in this case
#ifndef _WIN32
free(r);
#else
VirtualFree((const void*) r, MEM_RELEASE);
#endif
return NULL;
}
// Register the memory in the secure memory registry
SecureMemoryRegistry::i()->add(r, n * sizeof(T));
return r;
#else
pointer r = (pointer)(::operator new(n * sizeof(T)));
if (r == NULL)
{
ERROR_MSG("Out of memory");
return NULL;
}
// Register the memory in the secure memory registry
SecureMemoryRegistry::i()->add(r, n * sizeof(T));
return r;
#endif // SENSITIVE_NON_PAGED
}
// Deallocate n elements of type T
inline void deallocate(pointer p, size_type n)
{
#ifdef PARANOID
// First toggle all bits on
memset(p, 0xFF, n * sizeof(T));
#endif // PARANOID
// Toggle all bits off
memset(p, 0x00, n * sizeof(T));
// Unregister the memory from the secure memory registry
SecureMemoryRegistry::i()->remove(p);
#ifdef SENSITIVE_NON_PAGED
#ifndef _WIN32
munlock((const void*) p, n * sizeof(T));
#else
VirtualUnlock((const void*) p, n * sizeof(T));
#endif
#ifndef _WIN32
free(p);
#else
VirtualFree((const void*) r, MEM_RELEASE);
#endif
#else
// Release the memory
::operator delete((void*) p);
#endif // SENSITIVE_NON_PAGED
}
// Initialise allocate storage with a value
void construct(pointer p, const T& value)
{
new((void*) p)T(value);
}
// Destroy elements of initialised storage
void destroy(pointer p)
{
// Call destructor
p->~T();
}
// Comparison operators
inline bool operator==(SecureAllocator const&) const { return true; }
inline bool operator!=(SecureAllocator const&) const { return false; }
};
#endif // !_SOFTHSM_V2_SECUREALLOCATOR_H
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