Switch to memcpy for accessing misaligned data.
Bug: http://b/31532493
Using misaligned pointers forces us to potentially take the address of
members in a packed structure (which is now a warning/error in the
latest Clang). Using memcpy() is the proper way to handle this kind of
problem, as the compiler can insert the proper instructions (and usually
elide the memcpy() entirely).
Test: Built correctly with updated compilers.
Change-Id: Ia1f6eb62cf19404ff76b71d3c6c7ffffa1403120
diff --git a/base/include/android-base/memory.h b/base/include/android-base/memory.h
index 3a2f8fa..9971226 100644
--- a/base/include/android-base/memory.h
+++ b/base/include/android-base/memory.h
@@ -20,25 +20,19 @@
namespace android {
namespace base {
-// Use packed structures for access to unaligned data on targets with alignment
+// Use memcpy for access to unaligned data on targets with alignment
// restrictions. The compiler will generate appropriate code to access these
// structures without generating alignment exceptions.
template <typename T>
-static inline T get_unaligned(const T* address) {
- struct unaligned {
- T v;
- } __attribute__((packed));
- const unaligned* p = reinterpret_cast<const unaligned*>(address);
- return p->v;
+static inline T get_unaligned(const void* address) {
+ T result;
+ memcpy(&result, address, sizeof(T));
+ return result;
}
template <typename T>
-static inline void put_unaligned(T* address, T v) {
- struct unaligned {
- T v;
- } __attribute__((packed));
- unaligned* p = reinterpret_cast<unaligned*>(address);
- p->v = v;
+static inline void put_unaligned(void* address, T v) {
+ memcpy(address, &v, sizeof(T));
}
} // namespace base
diff --git a/gatekeeperd/SoftGateKeeper.h b/gatekeeperd/SoftGateKeeper.h
index 8b15d72..cb02a6f 100644
--- a/gatekeeperd/SoftGateKeeper.h
+++ b/gatekeeperd/SoftGateKeeper.h
@@ -152,7 +152,7 @@
}
bool DoVerify(const password_handle_t *expected_handle, const SizedBuffer &password) {
- uint64_t user_id = android::base::get_unaligned(&expected_handle->user_id);
+ uint64_t user_id = android::base::get_unaligned<secure_id_t>(&expected_handle->user_id);
FastHashMap::const_iterator it = fast_hash_map_.find(user_id);
if (it != fast_hash_map_.end() && VerifyFast(it->second, password)) {
return true;