[compiler-rt] r309883 - [msan] Check for pvalloc overflow

[Kostya Kortchinsky via llvm-commits]

Author: cryptoad
Date: Wed Aug  2 13:32:12 2017
New Revision: 309883

URL: http://llvm.org/viewvc/llvm-project?rev=309883&view=rev
Log:
[msan] Check for pvalloc overflow

Summary:
CheckForPvallocOverflow was introduced with D35818 to detect when pvalloc
would wrap when rounding up to the next multiple of the page size.

Add this check to MSan's pvalloc implementation.

This time I made sure I was actually running (and writing) the correct tests,
and that they are passing...

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D36164

Modified:
    compiler-rt/trunk/lib/msan/msan_allocator.cc
    compiler-rt/trunk/lib/msan/tests/msan_test.cc

Modified: compiler-rt/trunk/lib/msan/msan_allocator.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan_allocator.cc?rev=309883&r1=309882&r2=309883&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/msan_allocator.cc (original)
+++ compiler-rt/trunk/lib/msan/msan_allocator.cc Wed Aug  2 13:32:12 2017
@@ -255,6 +255,10 @@ void *msan_valloc(uptr size, StackTrace
 
 void *msan_pvalloc(uptr size, StackTrace *stack) {
   uptr PageSize = GetPageSizeCached();
+  if (UNLIKELY(CheckForPvallocOverflow(size, PageSize))) {
+    errno = errno_ENOMEM;
+    return Allocator::FailureHandler::OnBadRequest();
+  }
   // pvalloc(0) should allocate one page.
   size = size ? RoundUpTo(size, PageSize) : PageSize;
   return SetErrnoOnNull(MsanAllocate(stack, size, PageSize, false));

Modified: compiler-rt/trunk/lib/msan/tests/msan_test.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/tests/msan_test.cc?rev=309883&r1=309882&r2=309883&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/tests/msan_test.cc (original)
+++ compiler-rt/trunk/lib/msan/tests/msan_test.cc Wed Aug  2 13:32:12 2017
@@ -3449,6 +3449,12 @@ TEST(MemorySanitizer, pvalloc) {
   EXPECT_EQ(0U, (uintptr_t)p % PageSize);
   EXPECT_EQ(PageSize, __sanitizer_get_allocated_size(p));
   free(p);
+
+  // Overflows should be caught.
+  EXPECT_DEATH(p = pvalloc((uintptr_t)-1),
+               "allocator is terminating the process instead of returning 0");
+  EXPECT_DEATH(p = pvalloc((uintptr_t)-(PageSize - 1)),
+               "allocator is terminating the process instead of returning 0");
 }
 #endif