[compiler-rt] r176799 - [sanitizer] make SizeClassAllocator64::GetBlockBegin more bullet proof (by Sergey Matveev)

[Kostya Serebryany]

Author: kcc
Date: Mon Mar 11 04:43:12 2013
New Revision: 176799

URL: http://llvm.org/viewvc/llvm-project?rev=176799&view=rev
Log:
[sanitizer] make SizeClassAllocator64::GetBlockBegin more bullet proof (by Sergey Matveev)

Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator.h
    compiler-rt/trunk/lib/sanitizer_common/tests/sanitizer_allocator_test.cc

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator.h?rev=176799&r1=176798&r2=176799&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator.h (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_allocator.h Mon Mar 11 04:43:12 2013
@@ -358,10 +358,12 @@ class SizeClassAllocator64 {
   void *GetBlockBegin(void *p) {
     uptr class_id = GetSizeClass(p);
     uptr size = SizeClassMap::Size(class_id);
+    if (!size) return 0;
     uptr chunk_idx = GetChunkIdx((uptr)p, size);
     uptr reg_beg = (uptr)p & ~(kRegionSize - 1);
     uptr beg = chunk_idx * size;
     uptr next_beg = beg + size;
+    if (class_id >= kNumClasses) return 0;
     RegionInfo *region = GetRegionInfo(class_id);
     if (region->mapped_user >= next_beg)
       return reinterpret_cast<void*>(reg_beg + beg);

Modified: compiler-rt/trunk/lib/sanitizer_common/tests/sanitizer_allocator_test.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/tests/sanitizer_allocator_test.cc?rev=176799&r1=176798&r2=176799&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/tests/sanitizer_allocator_test.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/tests/sanitizer_allocator_test.cc Mon Mar 11 04:43:12 2013
@@ -115,6 +115,12 @@ void TestSizeClassAllocator() {
     CHECK_EQ(last_total_allocated, total_allocated);
   }
 
+  // Check that GetBlockBegin never crashes.
+  for (uptr x = 0, step = kAddressSpaceSize / 100000;
+       x < kAddressSpaceSize - step; x += step)
+    if (a->PointerIsMine(reinterpret_cast<void *>(x)))
+      Ident(a->GetBlockBegin(reinterpret_cast<void *>(x)));
+
   a->TestOnlyUnmap();
   delete a;
 }