[Minor] Add a memory erasing allocator

diff --git a/src/libutil/cxx/util.hxx b/src/libutil/cxx/util.hxx
index 0df3349a3dd58eb73009ea0ab082eea8eff2ba92..2e0308bd200bb10529d9a5f218ca184b3d0769cf 100644 (file)
--- a/src/libutil/cxx/util.hxx
+++ b/src/libutil/cxx/util.hxx
@@ -129,6 +129,27 @@ constexpr auto enumerate(T && iterable)
        return iterable_wrapper{ std::forward<T>(iterable) };
 }
 
+/**
+ * Allocator that cleans up memory in a secure way on destruction
+ * @tparam T
+ */
+template <class T> class secure_mem_allocator : public std::allocator<T>
+{
+public:
+       using pointer = typename std::allocator<T>::pointer;
+       using size_type = typename std::allocator<T>::size_type;
+       template<class U> struct rebind { typedef secure_mem_allocator<U> other; };
+       secure_mem_allocator() noexcept = default;
+       secure_mem_allocator(const secure_mem_allocator &) noexcept {}
+       template <class U> explicit secure_mem_allocator(const secure_mem_allocator<U>&) noexcept {}
+
+       void deallocate(pointer p, size_type num) noexcept {
+               rspamd_explicit_memzero((void *)p, num);
+               std::allocator<T>::deallocate(p, num);
+       }
+};
+
+
 }
 
 #endif //RSPAMD_UTIL_HXX