Blacklist some vector functions for CFI.

This CL blacklists some vector functions (construct, copy, splat,
move) that use reinterpret_cast on freshly allocated memory (where the
object doesn't exist yet). This is technically correct, but not
friendly for CFI, which enforces stricter checking to catch type
confusion errors. Blacklisting these specific functions from CFI does
not cause an appreciable coverage loss though, so this should be fine.

Bug: 36219323
Test: Builds and boots, and the reinterpret error goes away on CFI builds.
Test: All 98 libutils_tests pass
Change-Id: I4944b179116bb1e1608d92697e95e182d8c0ac9f

2 files changed, 24 insertions, 10 deletions

diff --git a/libutils/include/utils/SortedVector.h b/libutils/include/utils/SortedVector.h
index d57465d33..5b2a23200 100644
--- a/libutils/include/utils/SortedVector.h
+++ b/libutils/include/utils/SortedVector.h
@@ -252,7 +252,7 @@ ssize_t SortedVector<TYPE>::removeItemsAt(size_t index, size_t count) {
 // ---------------------------------------------------------------------------
 
 template<class TYPE>
-void SortedVector<TYPE>::do_construct(void* storage, size_t num) const {
+UTILS_VECTOR_NO_CFI void SortedVector<TYPE>::do_construct(void* storage, size_t num) const {
     construct_type( reinterpret_cast<TYPE*>(storage), num );
 }
 
@@ -262,22 +262,22 @@ void SortedVector<TYPE>::do_destroy(void* storage, size_t num) const {
 }
 
 template<class TYPE>
-void SortedVector<TYPE>::do_copy(void* dest, const void* from, size_t num) const {
+UTILS_VECTOR_NO_CFI void SortedVector<TYPE>::do_copy(void* dest, const void* from, size_t num) const {
     copy_type( reinterpret_cast<TYPE*>(dest), reinterpret_cast<const TYPE*>(from), num );
 }
 
 template<class TYPE>
-void SortedVector<TYPE>::do_splat(void* dest, const void* item, size_t num) const {
+UTILS_VECTOR_NO_CFI void SortedVector<TYPE>::do_splat(void* dest, const void* item, size_t num) const {
     splat_type( reinterpret_cast<TYPE*>(dest), reinterpret_cast<const TYPE*>(item), num );
 }
 
 template<class TYPE>
-void SortedVector<TYPE>::do_move_forward(void* dest, const void* from, size_t num) const {
+UTILS_VECTOR_NO_CFI void SortedVector<TYPE>::do_move_forward(void* dest, const void* from, size_t num) const {
     move_forward_type( reinterpret_cast<TYPE*>(dest), reinterpret_cast<const TYPE*>(from), num );
 }
 
 template<class TYPE>
-void SortedVector<TYPE>::do_move_backward(void* dest, const void* from, size_t num) const {
+UTILS_VECTOR_NO_CFI void SortedVector<TYPE>::do_move_backward(void* dest, const void* from, size_t num) const {
     move_backward_type( reinterpret_cast<TYPE*>(dest), reinterpret_cast<const TYPE*>(from), num );
 }
 
diff --git a/libutils/include/utils/Vector.h b/libutils/include/utils/Vector.h
index 3189fd623..7e00123f7 100644
--- a/libutils/include/utils/Vector.h
+++ b/libutils/include/utils/Vector.h
@@ -24,6 +24,20 @@
 #include <utils/TypeHelpers.h>
 #include <utils/VectorImpl.h>
 
+/*
+ * Used to blacklist some functions from CFI.
+ *
+ */
+#ifndef __has_attribute
+#define __has_attribute(x) 0
+#endif
+
+#if __has_attribute(no_sanitize)
+#define UTILS_VECTOR_NO_CFI __attribute__((no_sanitize("cfi")))
+#else
+#define UTILS_VECTOR_NO_CFI
+#endif
+
 // ---------------------------------------------------------------------------
 
 namespace android {
@@ -380,7 +394,7 @@ status_t Vector<TYPE>::sort(Vector<TYPE>::compar_r_t cmp, void* state) {
 // ---------------------------------------------------------------------------
 
 template<class TYPE>
-void Vector<TYPE>::do_construct(void* storage, size_t num) const {
+UTILS_VECTOR_NO_CFI void Vector<TYPE>::do_construct(void* storage, size_t num) const {
     construct_type( reinterpret_cast<TYPE*>(storage), num );
 }
 
@@ -390,22 +404,22 @@ void Vector<TYPE>::do_destroy(void* storage, size_t num) const {
 }
 
 template<class TYPE>
-void Vector<TYPE>::do_copy(void* dest, const void* from, size_t num) const {
+UTILS_VECTOR_NO_CFI void Vector<TYPE>::do_copy(void* dest, const void* from, size_t num) const {
     copy_type( reinterpret_cast<TYPE*>(dest), reinterpret_cast<const TYPE*>(from), num );
 }
 
 template<class TYPE>
-void Vector<TYPE>::do_splat(void* dest, const void* item, size_t num) const {
+UTILS_VECTOR_NO_CFI void Vector<TYPE>::do_splat(void* dest, const void* item, size_t num) const {
     splat_type( reinterpret_cast<TYPE*>(dest), reinterpret_cast<const TYPE*>(item), num );
 }
 
 template<class TYPE>
-void Vector<TYPE>::do_move_forward(void* dest, const void* from, size_t num) const {
+UTILS_VECTOR_NO_CFI void Vector<TYPE>::do_move_forward(void* dest, const void* from, size_t num) const {
     move_forward_type( reinterpret_cast<TYPE*>(dest), reinterpret_cast<const TYPE*>(from), num );
 }
 
 template<class TYPE>
-void Vector<TYPE>::do_move_backward(void* dest, const void* from, size_t num) const {
+UTILS_VECTOR_NO_CFI void Vector<TYPE>::do_move_backward(void* dest, const void* from, size_t num) const {
     move_backward_type( reinterpret_cast<TYPE*>(dest), reinterpret_cast<const TYPE*>(from), num );
 }