Update Unit tests and reference code

This patch adds a suite of tests for OEMCrypto that verifying buffer
overflow and off-by-one errors. The reference code has also been
updated to pass these tests.

The ODK library and the OEMCrypto API have not changed since the
release of version 16.4.

util/include/log.h

@@ -1,6 +1,6 @@
 // Copyright 2018 Google LLC. All Rights Reserved. This file and proprietary
-// source code may only be used and distributed under the Widevine Master
-// License Agreement.
+// source code may only be used and distributed under the Widevine License
+// Agreement.
 //
 // Log - Platform independent interface for a Logging class
 //
@@ -33,8 +33,18 @@ extern LogPriority g_cutoff;
 // unit tests.
 CORE_UTIL_EXPORT void InitLogging();
 
+// Only enable format specifier warnings on LP64 systems.  There is
+// no easy portable method to handle format specifiers for int64_t.
+#if (defined(__GNUC__) || defined(__clang__)) && defined(__LP64__)
+[[gnu::format(printf, 5, 6)]] CORE_UTIL_EXPORT void Log(const char* file,
+                                                        const char* function,
+                                                        int line,
+                                                        LogPriority level,
+                                                        const char* fmt, ...);
+#else
 CORE_UTIL_EXPORT void Log(const char* file, const char* function, int line,
                           LogPriority level, const char* fmt, ...);
+#endif
 
 // Log APIs
 #ifndef LOGE