[PAC][compiler-rt][UBSan] Strip signed vptr instead of authenticating…

… it (llvm#100153) vptr cannot be authenticated without knowing the class type if it was signed with type discrimination. Co-authored-by: Oliver Hunt <[email protected]> (cherry picked from commit 0a6a3c1)
llvmbot · Jul 24, 2024 · 95ed2d0 · 95ed2d0
1 parent 843276a
commit 95ed2d0
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/compiler-rt/lib/ubsan/ubsan_type_hash_itanium.cpp b/compiler-rt/lib/ubsan/ubsan_type_hash_itanium.cpp
@@ -207,7 +207,7 @@ struct VtablePrefix {
   std::type_info *TypeInfo;
 };
 VtablePrefix *getVtablePrefix(void *Vtable) {
-  Vtable = ptrauth_auth_data(Vtable, ptrauth_key_cxx_vtable_pointer, 0);
+  Vtable = ptrauth_strip(Vtable, ptrauth_key_cxx_vtable_pointer);
   VtablePrefix *Vptr = reinterpret_cast<VtablePrefix*>(Vtable);
   VtablePrefix *Prefix = Vptr - 1;
   if (!IsAccessibleMemoryRange((uptr)Prefix, sizeof(VtablePrefix)))