add and use constant time 32 byte equality function

3 files changed, 26 insertions, 5 deletions

diff --git a/src/crypto/CMakeLists.txt b/src/crypto/CMakeLists.txt
index 71dcedcab..0c635e7cb 100644
--- a/src/crypto/CMakeLists.txt
+++ b/src/crypto/CMakeLists.txt
@@ -78,6 +78,7 @@ target_link_libraries(cncrypto
   PUBLIC
     epee
     ${Boost_SYSTEM_LIBRARY}
+    ${SODIUM_LIBRARY}
   PRIVATE
     ${EXTRA_LIBRARIES})
 
diff --git a/src/crypto/crypto.h b/src/crypto/crypto.h
index c1576a218..33cc0a25a 100644
--- a/src/crypto/crypto.h
+++ b/src/crypto/crypto.h
@@ -283,6 +283,6 @@ namespace crypto {
 }
 
 CRYPTO_MAKE_HASHABLE(public_key)
-CRYPTO_MAKE_HASHABLE(secret_key)
+CRYPTO_MAKE_HASHABLE_CONSTANT_TIME(secret_key)
 CRYPTO_MAKE_HASHABLE(key_image)
 CRYPTO_MAKE_COMPARABLE(signature)
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)
+