From d2e26c23f3caa7928c46c3a6bded85fdc1a68cb3 Mon Sep 17 00:00:00 2001
From: moneromooo-monero <moneromooo-monero@users.noreply.github.com>
Date: Wed, 13 Jun 2018 18:23:06 +0100
Subject: add and use constant time 32 byte equality function

---
 src/crypto/generic-ops.h | 28 ++++++++++++++++++++++++----
 1 file changed, 24 insertions(+), 4 deletions(-)

(limited to 'src/crypto/generic-ops.h')

diff --git a/src/crypto/generic-ops.h b/src/crypto/generic-ops.h
index 62bc758c9..42b98706e 100644
--- a/src/crypto/generic-ops.h
+++ b/src/crypto/generic-ops.h
@@ -33,19 +33,30 @@
 #include <cstddef>
 #include <cstring>
 #include <functional>
+#include <sodium/crypto_verify_32.h>
 
 #define CRYPTO_MAKE_COMPARABLE(type) \
 namespace crypto { \
   inline bool operator==(const type &_v1, const type &_v2) { \
-    return std::memcmp(&_v1, &_v2, sizeof(type)) == 0; \
+    return !memcmp(&_v1, &_v2, sizeof(_v1)); \
   } \
   inline bool operator!=(const type &_v1, const type &_v2) { \
-    return std::memcmp(&_v1, &_v2, sizeof(type)) != 0; \
+    return !operator==(_v1, _v2); \
   } \
 }
 
-#define CRYPTO_MAKE_HASHABLE(type) \
-CRYPTO_MAKE_COMPARABLE(type) \
+#define CRYPTO_MAKE_COMPARABLE_CONSTANT_TIME(type) \
+namespace crypto { \
+  inline bool operator==(const type &_v1, const type &_v2) { \
+    static_assert(sizeof(_v1) == 32, "constant time comparison is only implenmted for 32 bytes"); \
+    return crypto_verify_32((const unsigned char*)&_v1, (const unsigned char*)&_v2) == 0; \
+  } \
+  inline bool operator!=(const type &_v1, const type &_v2) { \
+    return !operator==(_v1, _v2); \
+  } \
+}
+
+#define CRYPTO_DEFINE_HASH_FUNCTIONS(type) \
 namespace crypto { \
   static_assert(sizeof(std::size_t) <= sizeof(type), "Size of " #type " must be at least that of size_t"); \
   inline std::size_t hash_value(const type &_v) { \
@@ -60,3 +71,12 @@ namespace std { \
     } \
   }; \
 }
+
+#define CRYPTO_MAKE_HASHABLE(type) \
+CRYPTO_MAKE_COMPARABLE(type) \
+CRYPTO_DEFINE_HASH_FUNCTIONS(type)
+
+#define CRYPTO_MAKE_HASHABLE_CONSTANT_TIME(type) \
+CRYPTO_MAKE_COMPARABLE_CONSTANT_TIME(type) \
+CRYPTO_DEFINE_HASH_FUNCTIONS(type)
+
-- 
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