libbinder Parcel: Fix ubsan error in readData

arve-android · arve-android · commit b61a07068ae7 · 2024-10-08T20:11:20.000-07:00
Use don't cast the result of readInplace before calling memcpy to align
the data. With clang-r522817 passing an unaligned pointer to memcpy also
triggers a ubsan error.

Bug: 354981705
Change-Id: Ibd104bcfac519211857f1e9e93a1ec35e7bcd773
diff --git a/libs/binder/include/binder/Parcel.h b/libs/binder/include/binder/Parcel.h
@@ -1240,7 +1240,7 @@ class Parcel {
             if (__builtin_mul_overflow(size, sizeof(T), &dataLen)) {
                 return -EOVERFLOW;
             }
-            auto data = reinterpret_cast<const T*>(readInplace(dataLen));
+            auto data = readInplace(dataLen);
             if (data == nullptr) return BAD_VALUE;
             // std::vector::insert and similar methods will require type-dependent
             // byte alignment when inserting from a const iterator such as `data`,

Original file line number	Diff line number	Diff line change
`@@ -1240,7 +1240,7 @@ class Parcel {`
`1240`	`1240`	`if (__builtin_mul_overflow(size, sizeof(T), &dataLen)) {`
`1241`	`1241`	`return -EOVERFLOW;`
`1242`	`1242`	`}`
`1243`		`- auto data = reinterpret_cast<const T*>(readInplace(dataLen));`
	`1243`	`+ auto data = readInplace(dataLen);`
`1244`	`1244`	`if (data == nullptr) return BAD_VALUE;`
`1245`	`1245`	`// std::vector::insert and similar methods will require type-dependent`
`1246`	`1246`	// byte alignment when inserting from a const iterator such as `data`,