[PATCH] D15008: [sanitizer] Fix a crash in SizeClassAllocator32 with an out-of-range pointer

[Kuba Brecka via llvm-commits]

kubabrecka created this revision.
kubabrecka added reviewers: samsonov, glider, kcc, dvyukov.
kubabrecka added subscribers: llvm-commits, zaks.anna.
Herald added a subscriber: aemerson.

This only happens on a 64-bit platform that uses SizeClassAllocator32 (e.g. ASan on AArch64).  When querying a large invalid pointer about its size, e.g. with:

    __sanitizer_get_allocated_size(0xdeadbeefdeadbeef);

...an assertion will fail:

    AddressSanitizer CHECK failed: .../sanitizer_allocator.h "((res)) < ((kNumPossibleRegions))"

This patch changes `PointerIsMine` to return false if the pointer is outside of [kSpaceBeg, kSpaceBeg + kSpaceSize).

http://reviews.llvm.org/D15008

Files:
  lib/sanitizer_common/sanitizer_allocator.h

Index: lib/sanitizer_common/sanitizer_allocator.h
===================================================================
--- lib/sanitizer_common/sanitizer_allocator.h
+++ lib/sanitizer_common/sanitizer_allocator.h
@@ -749,6 +749,9 @@
   }
 
   bool PointerIsMine(const void *p) {
+    uptr mem = reinterpret_cast<uptr>(p);
+    if (mem < kSpaceBeg || mem >= kSpaceBeg + kSpaceSize)
+      return false;
     return GetSizeClass(p) != 0;
   }
 


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