secblock.h

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// secblock.h - written and placed in the public domain by Wei Dai


#ifndef CRYPTOPP_SECBLOCK_H
#define CRYPTOPP_SECBLOCK_H

#include "config.h"
#include "stdcpp.h"
#include "misc.h"

#if CRYPTOPP_MSC_VERSION
# pragma warning(push)
# pragma warning(disable: 4700)
# if (CRYPTOPP_MSC_VERSION >= 1400)
#  pragma warning(disable: 6386)
# endif
#endif

NAMESPACE_BEGIN(CryptoPP)

// ************** secure memory allocation ***************

template<class T>
class AllocatorBase
{
public:
        typedef T value_type;
        typedef size_t size_type;
#ifdef CRYPTOPP_MSVCRT6
        typedef ptrdiff_t difference_type;
#else
        typedef std::ptrdiff_t difference_type;
#endif
        typedef T * pointer;
        typedef const T * const_pointer;
        typedef T & reference;
        typedef const T & const_reference;

        pointer address(reference r) const {return (&r);}
        const_pointer address(const_reference r) const {return (&r); }
        void construct(pointer p, const T& val) {new (p) T(val);}
        void destroy(pointer p) {CRYPTOPP_UNUSED(p); p->~T();}

        CRYPTOPP_CONSTEXPR size_type max_size() const {return (SIZE_MAX/sizeof(T));}

#if defined(CRYPTOPP_CXX11_VARIADIC_TEMPLATES) || defined(CRYPTOPP_DOXYGEN_PROCESSING)

    template<typename U, typename... Args>
    void construct(U* ptr, Args&&... args) {::new ((void*)ptr) U(std::forward<Args>(args)...);}

    template<typename U>
    void destroy(U* ptr) {if(ptr) ptr->~U();}

#endif

protected:

        static void CheckSize(size_t size)
        {
                // C++ throws std::bad_alloc (C++03) or std::bad_array_new_length (C++11) here.
                if (size > (SIZE_MAX/sizeof(T)))
                        throw InvalidArgument("AllocatorBase: requested size would cause integer overflow");
        }
};

#define CRYPTOPP_INHERIT_ALLOCATOR_TYPES        \
typedef typename AllocatorBase<T>::value_type value_type;\
typedef typename AllocatorBase<T>::size_type size_type;\
typedef typename AllocatorBase<T>::difference_type difference_type;\
typedef typename AllocatorBase<T>::pointer pointer;\
typedef typename AllocatorBase<T>::const_pointer const_pointer;\
typedef typename AllocatorBase<T>::reference reference;\
typedef typename AllocatorBase<T>::const_reference const_reference;

template <class T, class A>
typename A::pointer StandardReallocate(A& alloc, T *oldPtr, typename A::size_type oldSize, typename A::size_type newSize, bool preserve)
{
        CRYPTOPP_ASSERT((oldPtr && oldSize) || !(oldPtr || oldSize));
        if (oldSize == newSize)
                return oldPtr;

        if (preserve)
        {
                typename A::pointer newPointer = alloc.allocate(newSize, NULL);
                const size_t copySize = STDMIN(oldSize, newSize) * sizeof(T);

                if (oldPtr && newPointer) {memcpy_s(newPointer, copySize, oldPtr, copySize);}
                alloc.deallocate(oldPtr, oldSize);
                return newPointer;
        }
        else
        {
                alloc.deallocate(oldPtr, oldSize);
                return alloc.allocate(newSize, NULL);
        }
}

template <class T, bool T_Align16 = false>
class AllocatorWithCleanup : public AllocatorBase<T>
{
public:
        CRYPTOPP_INHERIT_ALLOCATOR_TYPES

        pointer allocate(size_type size, const void *ptr = NULL)
        {
                CRYPTOPP_UNUSED(ptr); CRYPTOPP_ASSERT(ptr == NULL);
                this->CheckSize(size);
                if (size == 0)
                        return NULL;

#if CRYPTOPP_BOOL_ALIGN16
                // TODO: should this need the test 'size*sizeof(T) >= 16'?
                if (T_Align16 && size*sizeof(T) >= 16)
                        return (pointer)AlignedAllocate(size*sizeof(T));
#endif

                return (pointer)UnalignedAllocate(size*sizeof(T));
        }

        void deallocate(void *ptr, size_type size)
        {
                CRYPTOPP_ASSERT((ptr && size) || !(ptr || size));
                SecureWipeArray((pointer)ptr, size);

#if CRYPTOPP_BOOL_ALIGN16
                if (T_Align16 && size*sizeof(T) >= 16)
                        return AlignedDeallocate(ptr);
#endif

                UnalignedDeallocate(ptr);
        }

        pointer reallocate(T *oldPtr, size_type oldSize, size_type newSize, bool preserve)
        {
                CRYPTOPP_ASSERT((oldPtr && oldSize) || !(oldPtr || oldSize));
                return StandardReallocate(*this, oldPtr, oldSize, newSize, preserve);
        }

    template <class U> struct rebind { typedef AllocatorWithCleanup<U, T_Align16> other; };
#if _MSC_VER >= 1500
        AllocatorWithCleanup() {}
        template <class U, bool A> AllocatorWithCleanup(const AllocatorWithCleanup<U, A> &) {}
#endif
};

CRYPTOPP_DLL_TEMPLATE_CLASS AllocatorWithCleanup<byte>;
CRYPTOPP_DLL_TEMPLATE_CLASS AllocatorWithCleanup<word16>;
CRYPTOPP_DLL_TEMPLATE_CLASS AllocatorWithCleanup<word32>;
CRYPTOPP_DLL_TEMPLATE_CLASS AllocatorWithCleanup<word64>;
#if defined(CRYPTOPP_WORD128_AVAILABLE)
CRYPTOPP_DLL_TEMPLATE_CLASS AllocatorWithCleanup<word128, true>; // for Integer
#endif
#if CRYPTOPP_BOOL_X86
CRYPTOPP_DLL_TEMPLATE_CLASS AllocatorWithCleanup<word, true>;    // for Integer
#endif

template <class T>
class NullAllocator : public AllocatorBase<T>
{
public:
        //LCOV_EXCL_START
        CRYPTOPP_INHERIT_ALLOCATOR_TYPES

        // TODO: should this return NULL or throw bad_alloc? Non-Windows C++ standard
        // libraries always throw. And late mode Windows throws. Early model Windows
        // (circa VC++ 6.0) returned NULL.
        pointer allocate(size_type n, const void* unused = NULL)
        {
                CRYPTOPP_UNUSED(n); CRYPTOPP_UNUSED(unused);
                CRYPTOPP_ASSERT(false); return NULL;
        }

        void deallocate(void *p, size_type n)
        {
                CRYPTOPP_UNUSED(p); CRYPTOPP_UNUSED(n);
                CRYPTOPP_ASSERT(false);
        }

        CRYPTOPP_CONSTEXPR size_type max_size() const {return 0;}
        //LCOV_EXCL_STOP
};

template <class T, size_t S, class A = NullAllocator<T>, bool T_Align16 = false>
class FixedSizeAllocatorWithCleanup : public AllocatorBase<T>
{
public:
        CRYPTOPP_INHERIT_ALLOCATOR_TYPES

        FixedSizeAllocatorWithCleanup() : m_allocated(false) {}

        pointer allocate(size_type size)
        {
                CRYPTOPP_ASSERT(IsAlignedOn(m_array, 8));

                if (size <= S && !m_allocated)
                {
                        m_allocated = true;
                        return GetAlignedArray();
                }
                else
                        return m_fallbackAllocator.allocate(size);
        }

        pointer allocate(size_type size, const void *hint)
        {
                if (size <= S && !m_allocated)
                {
                        m_allocated = true;
                        return GetAlignedArray();
                }
                else
                        return m_fallbackAllocator.allocate(size, hint);
        }

        void deallocate(void *ptr, size_type size)
        {
                if (ptr == GetAlignedArray())
                {
                        CRYPTOPP_ASSERT(size <= S);
                        CRYPTOPP_ASSERT(m_allocated);
                        m_allocated = false;
                        SecureWipeArray((pointer)ptr, size);
                }
                else
                        m_fallbackAllocator.deallocate(ptr, size);
        }

        pointer reallocate(pointer oldPtr, size_type oldSize, size_type newSize, bool preserve)
        {
                if (oldPtr == GetAlignedArray() && newSize <= S)
                {
                        CRYPTOPP_ASSERT(oldSize <= S);
                        if (oldSize > newSize)
                                SecureWipeArray(oldPtr+newSize, oldSize-newSize);
                        return oldPtr;
                }

                pointer newPointer = allocate(newSize, NULL);
                if (preserve && newSize)
                {
                        const size_t copySize = STDMIN(oldSize, newSize);
                        memcpy_s(newPointer, sizeof(T)*newSize, oldPtr, sizeof(T)*copySize);
                }
                deallocate(oldPtr, oldSize);
                return newPointer;
        }

        CRYPTOPP_CONSTEXPR size_type max_size() const {return STDMAX(m_fallbackAllocator.max_size(), S);}

private:

#ifdef __BORLANDC__
        T* GetAlignedArray() {return m_array;}
        T m_array[S];
#else
        T* GetAlignedArray() {return (CRYPTOPP_BOOL_ALIGN16 && T_Align16) ? (T*)(void *)(((byte *)m_array) + (0-(size_t)m_array)%16) : m_array;}
        CRYPTOPP_ALIGN_DATA(8) T m_array[(CRYPTOPP_BOOL_ALIGN16 && T_Align16) ? S+8/sizeof(T) : S];
#endif

        A m_fallbackAllocator;
        bool m_allocated;
};

template <class T, class A = AllocatorWithCleanup<T> >
class SecBlock
{
public:
        typedef typename A::value_type value_type;
        typedef typename A::pointer iterator;
        typedef typename A::const_pointer const_iterator;
        typedef typename A::size_type size_type;

        explicit SecBlock(size_type size=0)
                : m_size(size), m_ptr(m_alloc.allocate(size, NULL)) { }

        SecBlock(const SecBlock<T, A> &t)
                : m_size(t.m_size), m_ptr(m_alloc.allocate(t.m_size, NULL)) {
                        CRYPTOPP_ASSERT((!t.m_ptr && !m_size) || (t.m_ptr && m_size));
                        if (t.m_ptr) {memcpy_s(m_ptr, m_size*sizeof(T), t.m_ptr, t.m_size*sizeof(T));}
                }

        SecBlock(const T *ptr, size_type len)
                : m_size(len), m_ptr(m_alloc.allocate(len, NULL)) {
                        CRYPTOPP_ASSERT((!m_ptr && !m_size) || (m_ptr && m_size));
                        if (ptr && m_ptr)
                                memcpy_s(m_ptr, m_size*sizeof(T), ptr, len*sizeof(T));
                        else if (m_size)
                                memset(m_ptr, 0, m_size*sizeof(T));
                }

        ~SecBlock()
                {m_alloc.deallocate(m_ptr, m_size);}

#ifdef __BORLANDC__
        operator T *() const
                {return (T*)m_ptr;}
#else
        operator const void *() const
                {return m_ptr;}
        operator void *()
                {return m_ptr;}

        operator const T *() const
                {return m_ptr;}
        operator T *()
                {return m_ptr;}
#endif

        iterator begin()
                {return m_ptr;}
        const_iterator begin() const
                {return m_ptr;}
        iterator end()
                {return m_ptr+m_size;}
        const_iterator end() const
                {return m_ptr+m_size;}

        typename A::pointer data() {return m_ptr;}
        typename A::const_pointer data() const {return m_ptr;}

        size_type size() const {return m_size;}
        bool empty() const {return m_size == 0;}

        byte * BytePtr() {return (byte *)m_ptr;}
        const byte * BytePtr() const {return (const byte *)m_ptr;}
        size_type SizeInBytes() const {return m_size*sizeof(T);}

        void Assign(const T *ptr, size_type len)
        {
                New(len);
                if (m_ptr && ptr && len)
                        {memcpy_s(m_ptr, m_size*sizeof(T), ptr, len*sizeof(T));}
        }

        void Assign(const SecBlock<T, A> &t)
        {
                if (this != &t)
                {
                        New(t.m_size);
                        if (m_ptr && t.m_ptr && t.m_size)
                                {memcpy_s(m_ptr, m_size*sizeof(T), t, t.m_size*sizeof(T));}
                }
        }

        SecBlock<T, A>& operator=(const SecBlock<T, A> &t)
        {
                // Assign guards for self-assignment
                Assign(t);
                return *this;
        }

        SecBlock<T, A>& operator+=(const SecBlock<T, A> &t)
        {
                CRYPTOPP_ASSERT((!t.m_ptr && !t.m_size) || (t.m_ptr && t.m_size));

                if(t.m_size)
                {
                        const size_type oldSize = m_size;
                        if(this != &t)  // s += t
                        {
                                Grow(m_size+t.m_size);
                                memcpy_s(m_ptr+oldSize, (m_size-oldSize)*sizeof(T), t.m_ptr, t.m_size*sizeof(T));
                        }
                        else            // t += t
                        {
                                Grow(m_size*2);
                                memcpy_s(m_ptr+oldSize, (m_size-oldSize)*sizeof(T), m_ptr, oldSize*sizeof(T));
                        }
                }
                return *this;
        }

        SecBlock<T, A> operator+(const SecBlock<T, A> &t)
        {
                CRYPTOPP_ASSERT((!m_ptr && !m_size) || (m_ptr && m_size));
                CRYPTOPP_ASSERT((!t.m_ptr && !t.m_size) || (t.m_ptr && t.m_size));
                if(!t.m_size) return SecBlock(*this);

                SecBlock<T, A> result(m_size+t.m_size);
                if(m_size) {memcpy_s(result.m_ptr, result.m_size*sizeof(T), m_ptr, m_size*sizeof(T));}
                memcpy_s(result.m_ptr+m_size, (result.m_size-m_size)*sizeof(T), t.m_ptr, t.m_size*sizeof(T));
                return result;
        }

        bool operator==(const SecBlock<T, A> &t) const
        {
                return m_size == t.m_size &&
                        VerifyBufsEqual(reinterpret_cast<const byte*>(m_ptr), reinterpret_cast<const byte*>(t.m_ptr), m_size*sizeof(T));
        }

        bool operator!=(const SecBlock<T, A> &t) const
        {
                return !operator==(t);
        }

        void New(size_type newSize)
        {
                m_ptr = m_alloc.reallocate(m_ptr, m_size, newSize, false);
                m_size = newSize;
        }

        void CleanNew(size_type newSize)
        {
                New(newSize);
                if (m_ptr) {memset_z(m_ptr, 0, m_size*sizeof(T));}
        }

        void Grow(size_type newSize)
        {
                if (newSize > m_size)
                {
                        m_ptr = m_alloc.reallocate(m_ptr, m_size, newSize, true);
                        m_size = newSize;
                }
        }

        void CleanGrow(size_type newSize)
        {
                if (newSize > m_size)
                {
                        m_ptr = m_alloc.reallocate(m_ptr, m_size, newSize, true);
                        memset_z(m_ptr+m_size, 0, (newSize-m_size)*sizeof(T));
                        m_size = newSize;
                }
        }

        void resize(size_type newSize)
        {
                m_ptr = m_alloc.reallocate(m_ptr, m_size, newSize, true);
                m_size = newSize;
        }

        void swap(SecBlock<T, A> &b)
        {
                // Swap must occur on the allocator in case its FixedSize that spilled into the heap.
                std::swap(m_alloc, b.m_alloc);
                std::swap(m_size, b.m_size);
                std::swap(m_ptr, b.m_ptr);
        }

// protected:
        A m_alloc;
        size_type m_size;
        T *m_ptr;
};

#ifdef CRYPTOPP_DOXYGEN_PROCESSING
class SecByteBlock : public SecBlock<byte> {};
class SecWordBlock : public SecBlock<word> {};
class AlignedSecByteBlock : public SecBlock<byte, AllocatorWithCleanup<byte, true> > {};
#else
typedef SecBlock<byte> SecByteBlock;
typedef SecBlock<word> SecWordBlock;
typedef SecBlock<byte, AllocatorWithCleanup<byte, true> > AlignedSecByteBlock;
#endif

// No need for move semantics on derived class *if* the class does not add any
//   data members; see http://stackoverflow.com/q/31755703, and Rule of {0|3|5}.

template <class T, unsigned int S, class A = FixedSizeAllocatorWithCleanup<T, S> >
class FixedSizeSecBlock : public SecBlock<T, A>
{
public:
        explicit FixedSizeSecBlock() : SecBlock<T, A>(S) {}
};

template <class T, unsigned int S, bool T_Align16 = true>
class FixedSizeAlignedSecBlock : public FixedSizeSecBlock<T, S, FixedSizeAllocatorWithCleanup<T, S, NullAllocator<T>, T_Align16> >
{
};

template <class T, unsigned int S, class A = FixedSizeAllocatorWithCleanup<T, S, AllocatorWithCleanup<T> > >
class SecBlockWithHint : public SecBlock<T, A>
{
public:
        explicit SecBlockWithHint(size_t size) : SecBlock<T, A>(size) {}
};

template<class T, bool A, class U, bool B>
inline bool operator==(const CryptoPP::AllocatorWithCleanup<T, A>&, const CryptoPP::AllocatorWithCleanup<U, B>&) {return (true);}
template<class T, bool A, class U, bool B>
inline bool operator!=(const CryptoPP::AllocatorWithCleanup<T, A>&, const CryptoPP::AllocatorWithCleanup<U, B>&) {return (false);}

NAMESPACE_END

NAMESPACE_BEGIN(std)
template <class T, class A>
inline void swap(CryptoPP::SecBlock<T, A> &a, CryptoPP::SecBlock<T, A> &b)
{
        a.swap(b);
}

#if defined(_STLP_DONT_SUPPORT_REBIND_MEMBER_TEMPLATE) || (defined(_STLPORT_VERSION) && !defined(_STLP_MEMBER_TEMPLATE_CLASSES))
// working for STLport 5.1.3 and MSVC 6 SP5
template <class _Tp1, class _Tp2>
inline CryptoPP::AllocatorWithCleanup<_Tp2>&
__stl_alloc_rebind(CryptoPP::AllocatorWithCleanup<_Tp1>& __a, const _Tp2*)
{
        return (CryptoPP::AllocatorWithCleanup<_Tp2>&)(__a);
}
#endif

NAMESPACE_END

#if CRYPTOPP_MSC_VERSION
# pragma warning(pop)
#endif

#endif