Switch to C23's memset_explicit().

Test: treehugger
Change-Id: Ib6ef45cedaf95fa251d0b03de0f14701f910d063

KeyBuffer.h

@@ -17,32 +17,18 @@
 #ifndef ANDROID_VOLD_KEYBUFFER_H
 #define ANDROID_VOLD_KEYBUFFER_H
 
-#include <cstring>
+#include <string.h>
 #include <memory>
 #include <vector>
 
 namespace android {
 namespace vold {
 
-/**
- * Variant of memset() that should never be optimized away. Borrowed from keymaster code.
- */
-#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
-
 // Allocator that delegates useful work to standard one but zeroes data before deallocating.
 class ZeroingAllocator : public std::allocator<char> {
   public:
     void deallocate(pointer p, size_type n) {
-        memset_s(p, 0, n);
+        memset_explicit(p, 0, n);
         std::allocator<char>::deallocate(p, n);
     }
 };

Keystore.cpp

@@ -48,7 +48,7 @@ KeystoreOperation::~KeystoreOperation() {
 }
 
 static void zeroize_vector(std::vector<uint8_t>& vec) {
-    memset_s(vec.data(), 0, vec.size());
+    memset_explicit(vec.data(), 0, vec.size());
 }
 
 static bool logKeystore2ExceptionIfPresent(::ndk::ScopedAStatus& rc, const std::string& func_name) {