From 2e615b1b1956135d822237808353caa9daa35c09 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Sun, 10 Feb 2019 13:12:05 +1100
Subject: [PATCH] hash/blake2: use aligned storage for u64 salt components

---
 hash/blake2.cpp | 11 ++++-------
 hash/blake2.hpp | 12 +++++++-----
 2 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/hash/blake2.cpp b/hash/blake2.cpp
index c3bec52..7ae2e6d 100644
--- a/hash/blake2.cpp
+++ b/hash/blake2.cpp
@@ -135,8 +135,8 @@ blake2::blake2 (cruft::view<const u08 *> key)
     if (key.size () > ::traits::max_key_bytes)
         throw std::invalid_argument ("key is too large");
 
-    std::fill (m_salt.begin (), m_salt.end (), 0);
-    memcpy (m_salt.data (), key.data (), key.size ());
+    std::fill (m_salt.val08.begin (), m_salt.val08.end (), 0);
+    memcpy (m_salt.val08.data (), key.data (), key.size ());
     m_keylen = key.size ();
 }
 
@@ -145,13 +145,11 @@ blake2::blake2 (cruft::view<const u08 *> key)
 blake2::digest_t
 blake2::operator() (cruft::view<const u08 *> data) const noexcept
 {
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wcast-align"
     auto h = ::traits::iv;
     h[0] ^= 0x01010000 ^ (m_keylen << 8) ^ sizeof (digest_t);
 
     if (m_keylen)
-        F (h, reinterpret_cast<const word_t*> (m_salt.data ()), ::traits::block_bytes, data.empty ());
+        F (h, m_salt.val64.data (), ::traits::block_bytes, data.empty ());
 
     // special case for the empty key and empty data
     if (!m_keylen && data.empty ()) {
@@ -164,7 +162,7 @@ blake2::operator() (cruft::view<const u08 *> data) const noexcept
     auto cursor = data.begin ();
     while (cursor + ::traits::block_bytes < data.end ()) {
         counter += ::traits::block_bytes;
-        F (h, reinterpret_cast<const word_t*> (cursor), counter, false);
+        F (h, cruft::cast::alignment<word_t const*> (cursor), counter, false);
         cursor += ::traits::block_bytes;
     }
 
@@ -178,5 +176,4 @@ blake2::operator() (cruft::view<const u08 *> data) const noexcept
     digest_t d;
     memcpy (&d, h.data (), sizeof (d));
     return d;
-#pragma GCC diagnostic pop
 }
diff --git a/hash/blake2.hpp b/hash/blake2.hpp
index 51d145c..954f02c 100644
--- a/hash/blake2.hpp
+++ b/hash/blake2.hpp
@@ -6,9 +6,9 @@
  * Copyright 2018 Danny Robson <danny@nerdcruft.net>
  */
 
-#ifndef CRUFT_CRYPTO_HASH_BLAKE2_HPP
-#define CRUFT_CRYPTO_HASH_BLAKE2_HPP
+#pragma once
 
+#include <cruft/util/std.hpp>
 #include <cruft/util/view.hpp>
 
 #include <array>
@@ -34,9 +34,11 @@ namespace cruft::crypto::hash {
         // updates, not because it's a functional requirement. either way we
         // need to copy at least 64 bytes, so the user shouldn't be copying
         // these too much regardless.
-        std::array<uint8_t,128> m_salt;
+        union {
+            std::array<u08,128> val08;
+            std::array<u64, 16> val64;
+        } m_salt;
+
         uint64_t m_keylen;
     };
 };
-
-#endif