Merge pull request #3707 from Rohde-Schwarz/span/loadstor

[std::span] {load,store}_{le,be}

src/lib/utils/concepts.h

@@ -33,6 +33,14 @@ struct is_strong_type<Strong<Ts...>> : std::true_type {};
 template <typename... Ts>
 constexpr bool is_strong_type_v = is_strong_type<std::remove_const_t<Ts>...>::value;
 
+template <typename T0, typename... Ts>
+struct all_same {
+      static constexpr bool value = (std::is_same_v<T0, Ts> && ...);
+};
+
+template <typename... Ts>
+static constexpr bool all_same_v = all_same<Ts...>::value;
+
 namespace ranges {
 
 /**
@@ -205,6 +213,10 @@ concept contiguous_strong_type = strong_type<T> && contiguous_container<T>;
 template <typename T>
 concept integral = std::is_integral_v<T>;
 
+// TODO: C++20 - replace with std::unsigned_integral
+template <typename T>
+concept unsigned_integral = std::is_integral_v<T> && std::is_unsigned_v<T>;
+
 }  // namespace concepts
 
 }  // namespace Botan

src/lib/utils/ghash/ghash.cpp

@@ -13,6 +13,8 @@
 #include <botan/internal/ct_utils.h>
 #include <botan/internal/loadstor.h>
 
+#include <array>
+
 namespace Botan {
 
 std::string GHASH::provider() const {
@@ -177,9 +179,12 @@ void GHASH::add_final_block(secure_vector<uint8_t>& hash, size_t ad_len, size_t
    * stack buffer is fine here since the text len is public
    * and the length of the AD is probably not sensitive either.
    */
-   uint8_t final_block[GCM_BS];
-   store_be<uint64_t>(final_block, 8 * ad_len, 8 * text_len);
-   ghash_update(hash, {final_block, GCM_BS});
+   std::array<uint8_t, GCM_BS> final_block;
+
+   const uint64_t ad_bits = 8 * ad_len;
+   const uint64_t text_bits = 8 * text_len;
+   store_be(final_block, ad_bits, text_bits);
+   ghash_update(hash, final_block);
 }
 
 void GHASH::final(std::span<uint8_t> mac) {