Shore up SecBlock Append for overlapping buffer

1 files changed, 15 insertions, 8 deletions

diff --git a/secblock.h b/secblock.h
index 40cb0b82..2e82b43f 100644
--- a/secblock.h
+++ b/secblock.h
@@ -891,9 +891,12 @@ public:
 	/// \since Crypto++ 2.0

 	void Assign(const T *ptr, size_type len)

 	{

-		New(len);

-		if (m_ptr && ptr)  // GCC analyzer warning

-			memcpy_s(m_ptr, m_size*sizeof(T), ptr, len*sizeof(T));

+		// ptr is unknown. It could be same array or different array.

+		// It could be same array at different offset so m_ptr!=ptr.

+		SecBlock<T, A> t(len);

+		if (t.m_ptr && ptr)  // GCC analyzer warning

+			memcpy_s(t.m_ptr, t.m_size*sizeof(T), ptr, len*sizeof(T));

+		std::swap(*this, t);

 		m_mark = ELEMS_MAX;

 	}

 

@@ -948,11 +951,15 @@ public:
 

 		if (len)

 		{

-			const size_type oldSize = m_size;

-			Grow(m_size+len);

-			if (m_ptr && ptr)  // GCC analyzer warning

-				memcpy_s(m_ptr+oldSize, (m_size-oldSize)*sizeof(T), ptr, len*sizeof(T));

-

+			// ptr is unknown. It could be same array or different array.

+			// It could be same array at different offset so m_ptr!=ptr.

+			SecBlock<T, A> t(m_size+len);

+			if (t.m_ptr && m_ptr && ptr)  // GCC analyzer warning

+			{

+				memcpy_s(t.m_ptr, t.m_size*sizeof(T), m_ptr, m_size*sizeof(T));

+				memcpy_s(t.m_ptr+m_size, (t.m_size-m_size)*sizeof(T), ptr, len*sizeof(T));

+			}

+			std::swap(*this, t);

 		}

 		m_mark = ELEMS_MAX;

 	}