Break out code that sets/wipes the raw buffer into separate functions

This is so that derived classes can use them more easily.  (Specifically, to
be able to set the raw buffer without the virtual Wipe() being called.)

Also: WIPE NEEDS TO SECURELY WIPE, not just free the buffer!

P4:7307228

Author: zpostfacto

src/common/keypair.cpp

@@ -391,7 +391,11 @@ bool CCryptoKeyBase::LoadFromAndWipeBuffer( void *pBuffer, size_t cBytes )
 
 CCryptoKeyBase_RawBuffer::~CCryptoKeyBase_RawBuffer()
 {
-	Wipe();
+	// Note that we don't call virtual Wipe() here.  We're in a
+	// destructor, so it would just call our own Wipe(),
+	// anyway, but that relies on a relatively subtle aspect
+	// ot C++ destructor semantics, and this is more clear.
+	InternalWipeRawDataBuffer();
 }
 
 bool CCryptoKeyBase_RawBuffer::IsValid() const
@@ -408,7 +412,12 @@ uint32 CCryptoKeyBase_RawBuffer::GetRawData( void *pData ) const
 
 bool CCryptoKeyBase_RawBuffer::SetRawData( const void *pData, size_t cbData )
 {
-	Wipe();
+	return InternalSetRawDataBuffer( pData, cbData );
+}
+
+bool CCryptoKeyBase_RawBuffer::InternalSetRawDataBuffer( const void *pData, size_t cbData )
+{
+	InternalWipeRawDataBuffer();
 	m_pData = (uint8*)malloc( cbData );
 	if ( !m_pData )
 		return false;
@@ -418,9 +427,15 @@ bool CCryptoKeyBase_RawBuffer::SetRawData( const void *pData, size_t cbData )
 }
 
 void CCryptoKeyBase_RawBuffer::Wipe()
+{
+	InternalWipeRawDataBuffer();
+}
+
+void CCryptoKeyBase_RawBuffer::InternalWipeRawDataBuffer()
 {
 	if ( m_pData )
 	{
+		SecureZeroMemory( m_pData, m_cbData );
 		free( m_pData );
 		m_pData = nullptr;
 	}

src/common/keypair.h

@@ -126,6 +126,8 @@ class CCryptoKeyBase_RawBuffer : public CCryptoKeyBase
 
 protected:
 	virtual bool SetRawData( const void *pData, size_t cbData ) override;
+	void InternalWipeRawDataBuffer();
+	bool InternalSetRawDataBuffer( const void *pData, size_t cbData );
 	inline CCryptoKeyBase_RawBuffer( ECryptoKeyType keyType ) : CCryptoKeyBase( keyType ), m_pData( nullptr ), m_cbData( 0 ) {}
 
 	uint8 *m_pData;