implement Keyguard base class
Base class for all hardware KG implementations.
Platform-specific subclasses need only provide keys
and a signature routine.
Change-Id: I354b136a7ee1c5352ac611d8b9093fd5f2ff47ac
diff --git a/include/keyguard/keyguard_utils.h b/include/keyguard/keyguard_utils.h
new file mode 100644
index 0000000..fd00248
--- /dev/null
+++ b/include/keyguard/keyguard_utils.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+#ifndef GOOGLE_KEYGUARD_UTILS_H_
+#define GOOGLE_KEYGUARD_UTILS_H_
+
+#include <string.h>
+
+namespace keyguard {
+/**
+ * Variant of memset() that uses GCC-specific pragmas to disable optimizations, so effect is not
+ * optimized away. This is important because we often need to wipe blocks of sensitive data from
+ * memory. As an additional convenience, this implementation avoids writing to NULL pointers.
+ */
+#ifdef __clang__
+#define OPTNONE __attribute__((optnone))
+#else // not __clang__
+#define OPTNONE __attribute__((optimize("O0")))
+#endif // not __clang__
+inline OPTNONE void* memset_s(void* s, int c, size_t n) {
+ if (!s)
+ return s;
+ return memset(s, c, n);
+}
+#undef OPTNONE
+
+/**
+ * Return the number of elements in array \p a.
+ */
+template <typename T, size_t N> inline size_t array_length(const T (&)[N]) {
+ return N;
+}
+
+static int memcmp_s(const void* p1, const void* p2, size_t length) {
+ const uint8_t* s1 = static_cast<const uint8_t*>(p1);
+ const uint8_t* s2 = static_cast<const uint8_t*>(p2);
+ uint8_t result = 0;
+ while (length-- > 0)
+ result |= *s1++ ^ *s2++;
+ return result == 0 ? 0 : 1;
+}
+
+};
+#endif //GOOGLE_KEYGUARD_UTILS_H_