[scudo] Fix isOwned on MTE devices. (#111060)
If called on address that is actually not owned, the tags could not
match. Disable tag checks in isOwned().
GitOrigin-RevId: 00989f4ab14c4cf41bbac258f2bf197cbbdc2b41
diff --git a/combined.h b/combined.h
index a5f1bc3..323a8b9 100644
--- a/combined.h
+++ b/combined.h
@@ -785,6 +785,9 @@
// A corrupted chunk will not be reported as owned, which is WAI.
bool isOwned(const void *Ptr) {
initThreadMaybe();
+ // If the allocation is not owned, the tags could be wrong.
+ ScopedDisableMemoryTagChecks x(
+ useMemoryTagging<AllocatorConfig>(Primary.Options.load()));
#ifdef GWP_ASAN_HOOKS
if (GuardedAlloc.pointerIsMine(Ptr))
return true;
diff --git a/memtag.h b/memtag.h
index 1f6983e..83ebe67 100644
--- a/memtag.h
+++ b/memtag.h
@@ -122,9 +122,12 @@
class ScopedDisableMemoryTagChecks {
uptr PrevTCO;
+ bool active;
public:
- ScopedDisableMemoryTagChecks() {
+ ScopedDisableMemoryTagChecks(bool cond = true) : active(cond) {
+ if (!active)
+ return;
__asm__ __volatile__(
R"(
.arch_extension memtag
@@ -135,6 +138,8 @@
}
~ScopedDisableMemoryTagChecks() {
+ if (!active)
+ return;
__asm__ __volatile__(
R"(
.arch_extension memtag
@@ -269,7 +274,7 @@
}
struct ScopedDisableMemoryTagChecks {
- ScopedDisableMemoryTagChecks() {}
+ ScopedDisableMemoryTagChecks(UNUSED bool cond = true) {}
};
inline NORETURN uptr selectRandomTag(uptr Ptr, uptr ExcludeMask) {
