[ORC-RT] Fix ptrauth signing for dlsym return value (#75972)

benlangmuir · web-flow · commit dc58f781b69b · 2023-12-19T14:56:42.000-08:00
dlsym signs text symbols as functions rather than data in dyld, so match
that for orc runtime dlsym. This fixes run_program on arm64e.
diff --git a/compiler-rt/lib/orc/macho_platform.cpp b/compiler-rt/lib/orc/macho_platform.cpp
@@ -825,6 +825,10 @@ void *MachOPlatformRuntimeState::dlsym(void *DSOHandle, const char *Symbol) {
     return nullptr;
   }
 
+  // Sign callable symbols as functions, to match dyld.
+  if ((Result.second & MachOExecutorSymbolFlags::Callable) ==
+      MachOExecutorSymbolFlags::Callable)
+    return reinterpret_cast<void *>(Result.first.toPtr<void(void)>());
   return Result.first.toPtr<void *>();
 }
 

Original file line number	Diff line number	Diff line change
`@@ -825,6 +825,10 @@ void MachOPlatformRuntimeState::dlsym(void DSOHandle, const char *Symbol) {`
`825`	`825`	`return nullptr;`
`826`	`826`	`}`
`827`	`827`
	`828`	`+ // Sign callable symbols as functions, to match dyld.`
	`829`	`+ if ((Result.second & MachOExecutorSymbolFlags::Callable) ==`
	`830`	`+ MachOExecutorSymbolFlags::Callable)`
	`831`	`+ return reinterpret_cast<void *>(Result.first.toPtr<void(void)>());`
`828`	`832`	`return Result.first.toPtr<void *>();`
`829`	`833`	`}`
`830`	`834`