[compiler-rt] r176078 - [asan] fix the output for range accesses (memset, etc); improve the tests; more strict checking in memcmp

[Kostya Serebryany]

Author: kcc
Date: Tue Feb 26 01:25:18 2013
New Revision: 176078

URL: http://llvm.org/viewvc/llvm-project?rev=176078&view=rev
Log:
[asan] fix the output for range accesses (memset, etc); improve the tests; more strict checking in memcmp

Modified:
    compiler-rt/trunk/lib/asan/asan_interceptors.cc
    compiler-rt/trunk/lib/asan/tests/asan_mem_test.cc
    compiler-rt/trunk/lib/asan/tests/asan_test.cc

Modified: compiler-rt/trunk/lib/asan/asan_interceptors.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_interceptors.cc?rev=176078&r1=176077&r2=176078&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_interceptors.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_interceptors.cc Tue Feb 26 01:25:18 2013
@@ -44,10 +44,11 @@ static inline bool QuickCheckForUnpoison
 #define ACCESS_MEMORY_RANGE(offset, size, isWrite) do {                 \
     uptr __offset = (uptr)(offset);                                     \
     uptr __size = (uptr)(size);                                         \
+    uptr __bad = 0;                                                     \
     if (!QuickCheckForUnpoisonedRegion(__offset, __size) &&             \
-        __asan_region_is_poisoned(__offset, __size)) {                  \
+        (__bad = __asan_region_is_poisoned(__offset, __size))) {        \
       GET_CURRENT_PC_BP_SP;                                             \
-      __asan_report_error(pc, bp, sp, __offset, isWrite, __size);       \
+      __asan_report_error(pc, bp, sp, __bad, isWrite, __size);          \
     }                                                                   \
   } while (0)
 
@@ -258,18 +259,13 @@ static inline int CharCaseCmp(unsigned c
 INTERCEPTOR(int, memcmp, const void *a1, const void *a2, uptr size) {
   if (!asan_inited) return internal_memcmp(a1, a2, size);
   ENSURE_ASAN_INITED();
-  unsigned char c1 = 0, c2 = 0;
-  const unsigned char *s1 = (const unsigned char*)a1;
-  const unsigned char *s2 = (const unsigned char*)a2;
-  uptr i;
-  for (i = 0; i < size; i++) {
-    c1 = s1[i];
-    c2 = s2[i];
-    if (c1 != c2) break;
-  }
-  ASAN_READ_RANGE(s1, Min(i + 1, size));
-  ASAN_READ_RANGE(s2, Min(i + 1, size));
-  return CharCmp(c1, c2);
+  if (flags()->replace_intrin) {
+    // We check the entire regions even if the first bytes of the buffers
+    // are different.
+    ASAN_READ_RANGE(a1, size);
+    ASAN_READ_RANGE(a2, size);
+  }
+  return REAL(memcmp(a1, a2, size));
 }
 
 INTERCEPTOR(void*, memcpy, void *to, const void *from, uptr size) {

Modified: compiler-rt/trunk/lib/asan/tests/asan_mem_test.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/tests/asan_mem_test.cc?rev=176078&r1=176077&r2=176078&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/tests/asan_mem_test.cc (original)
+++ compiler-rt/trunk/lib/asan/tests/asan_mem_test.cc Tue Feb 26 01:25:18 2013
@@ -225,6 +225,13 @@ TEST(AddressSanitizer, MemCmpOOBTest) {
   s1[size - 1] = '\0';
   s2[size - 1] = '\0';
   EXPECT_DEATH(Ident(memcmp)(s1, s2, size + 1), RightOOBReadMessage(0));
+
+  // Even if the buffers differ in the first byte, we still assume that
+  // memcmp may access the whole buffer and thus reporting the overflow here:
+  s1[0] = 1;
+  s2[0] = 123;
+  EXPECT_DEATH(Ident(memcmp)(s1, s2, size + 1), RightOOBReadMessage(0));
+
   free(s1);
   free(s2);
 }

Modified: compiler-rt/trunk/lib/asan/tests/asan_test.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/tests/asan_test.cc?rev=176078&r1=176077&r2=176078&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/tests/asan_test.cc (original)
+++ compiler-rt/trunk/lib/asan/tests/asan_test.cc Tue Feb 26 01:25:18 2013
@@ -716,7 +716,8 @@ TEST(AddressSanitizer, Store128Test) {
 string RightOOBErrorMessage(int oob_distance, bool is_write) {
   assert(oob_distance >= 0);
   char expected_str[100];
-  sprintf(expected_str, ASAN_PCRE_DOTALL "%s.*located %d bytes to the right",
+  sprintf(expected_str, ASAN_PCRE_DOTALL
+          "buffer-overflow.*%s.*located %d bytes to the right",
           is_write ? "WRITE" : "READ", oob_distance);
   return string(expected_str);
 }