[hwasan] do not check if freed pointer belonged to allocator.

[fmayer]

Summary

In that case it is very likely that there will be a tag mismatch anyway.

We handle the case that the pointer belongs to neither of the allocators
by getting a nullptr from allocator.GetBlockBegin.

[eugenis]

LGTM

[thakis]

This seems to break tests: http://45.33.8.238/linux/54105/step_10.txt

Any idea what's going wrong there?

(@pcc too)

[fmayer]

Reverted by rGde916a7b12adc842a2cc23505d78412e8b5166d2.

[fmayer]

non-app memory is always invalid free.

[fmayer]

fix MemIsApp

[fmayer]

Please take another look. Fixed the test failure.

[fmayer]

clang format

[eugenis]

LGTM

compiler-rt/lib/hwasan/hwasan_allocator.cpp

static bool PointerAndMemoryTagsMatch(void *tagged_ptr) {
   tag_t mem_tag = *reinterpret_cast<tag_t *>(
       MemToShadow(reinterpret_cast<uptr>(UntagPtr(tagged_ptr))));
   return PossiblyShortTagMatches(mem_tag, tagged_uptr, 1);
 }
 
 static bool CheckInvalidFree(StackTrace *stack, void *untagged_ptr,
                              void *tagged_ptr) {
   // This function can return true if halt_on_error is false.
-  if (!allocator.PointerIsMine(untagged_ptr) ||
+  if (!MemIsApp(reinterpret_cast<uptr>(untagged_ptr)) ||
       !PointerAndMemoryTagsMatch(tagged_ptr)) {
     ReportInvalidFree(stack, reinterpret_cast<uptr>(tagged_ptr));
     return true;
   }
   return false;
 }
 
 static void HwasanDeallocate(StackTrace *stack, void *tagged_ptr) {

compiler-rt/lib/hwasan/hwasan_linux.cpp

 }
 
 bool MemIsApp(uptr p) {
 // Memory outside the alias range has non-zero tags.
 #  if !defined(HWASAN_ALIASING_MODE)
   CHECK(GetTagFromPointer(p) == 0);
 #  endif
 
-  return p >= kHighMemStart || (p >= kLowMemStart && p <= kLowMemEnd);
+  return (p >= kHighMemStart && p <= kHighMemEnd) ||
+         (p >= kLowMemStart && p <= kLowMemEnd);
 }
 
 void InstallAtExitHandler() { atexit(HwasanAtExit); }
 
 // ---------------------- TSD ---------------- {{{1
 
 extern "C" void __hwasan_thread_enter() {
   hwasanThreadList().CreateCurrentThread()->InitRandomState();

compiler-rt/test/hwasan/TestCases/wild-free-realloc.c

 // RUN: %clang_hwasan %s -o %t && not %run %t 2>&1 | FileCheck %s
 
+#include <sanitizer/hwasan_interface.h>
 #include <stdlib.h>
 
 int main() {
+  __hwasan_enable_allocator_tagging();
   char *p = (char *)malloc(1);
   realloc(p + 0x10000000000, 2);
   // CHECK: ERROR: HWAddressSanitizer: invalid-free on address {{.*}} at pc {{[0x]+}}[[PC:.*]] on thread T{{[0-9]+}}
   // CHECK: #0 {{[0x]+}}{{.*}}[[PC]] in {{.*}}realloc
   // CHECK: #1 {{.*}} in main {{.*}}wild-free-realloc.c:[[@LINE-3]]
   // CHECK-NOT: Segmentation fault
   // CHECK-NOT: SIGSEGV
   return 0;
 }

compiler-rt/test/hwasan/TestCases/wild-free.c

 // RUN: %clang_hwasan %s -o %t && not %run %t 2>&1 | FileCheck %s
 
+#include <sanitizer/hwasan_interface.h>
 #include <stdlib.h>
 
 int main() {
+  __hwasan_enable_allocator_tagging();
   char *p = (char *)malloc(1);
   free(p + 0x10000000000);
   // CHECK: ERROR: HWAddressSanitizer: invalid-free on address {{.*}} at pc {{[0x]+}}[[PC:.*]] on thread T{{[0-9]+}}
   // CHECK: #0 {{[0x]+}}{{.*}}[[PC]] in {{.*}}free
   // CHECK: #1 {{.*}} in main {{.*}}wild-free.c:[[@LINE-3]]
   // CHECK-NOT: Segmentation fault
   // CHECK-NOT: SIGSEGV
   return 0;
 }