[compiler-rt] r197244 - [msan] Fix strncat interceptor, add missing tests.

[Evgeniy Stepanov]

Author: eugenis
Date: Fri Dec 13 10:31:59 2013
New Revision: 197244

URL: http://llvm.org/viewvc/llvm-project?rev=197244&view=rev
Log:
[msan] Fix strncat interceptor, add missing tests.

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

Modified: compiler-rt/trunk/lib/msan/msan_interceptors.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/msan/msan_interceptors.cc?rev=197244&r1=197243&r2=197244&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/msan_interceptors.cc (original)
+++ compiler-rt/trunk/lib/msan/msan_interceptors.cc Fri Dec 13 10:31:59 2013
@@ -284,11 +284,10 @@ INTERCEPTOR(char *, strcat, char *dest,
 INTERCEPTOR(char *, strncat, char *dest, const char *src, SIZE_T n) {  // NOLINT
   ENSURE_MSAN_INITED();
   SIZE_T dest_size = REAL(strlen)(dest);
-  SIZE_T copy_size = REAL(strlen)(src);
-  if (copy_size < n)
-    copy_size++;  // trailing \0
+  SIZE_T copy_size = REAL(strnlen)(src, n);
   char *res = REAL(strncat)(dest, src, n);  // NOLINT
   __msan_copy_poison(dest + dest_size, src, copy_size);
+  __msan_unpoison(dest + dest_size + copy_size, 1); // \0
   return res;
 }
 

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=197244&r1=197243&r2=197244&view=diff
==============================================================================
--- compiler-rt/trunk/lib/msan/tests/msan_test.cc (original)
+++ compiler-rt/trunk/lib/msan/tests/msan_test.cc Fri Dec 13 10:31:59 2013
@@ -1470,6 +1470,45 @@ TEST(MemorySanitizer, stpcpy) {  // NOLI
   EXPECT_NOT_POISONED(y[2]);
 }
 
+TEST(MemorySanitizer, strcat) {  // NOLINT
+  char a[10];
+  char b[] = "def";
+  strcpy(a, "abc");
+  __msan_poison(b + 1, 1);
+  strcat(a, b);
+  EXPECT_NOT_POISONED(a[3]);
+  EXPECT_POISONED(a[4]);
+  EXPECT_NOT_POISONED(a[5]);
+  EXPECT_NOT_POISONED(a[6]);
+  EXPECT_POISONED(a[7]);
+}
+
+TEST(MemorySanitizer, strncat) {  // NOLINT
+  char a[10];
+  char b[] = "def";
+  strcpy(a, "abc");
+  __msan_poison(b + 1, 1);
+  strncat(a, b, 5);
+  EXPECT_NOT_POISONED(a[3]);
+  EXPECT_POISONED(a[4]);
+  EXPECT_NOT_POISONED(a[5]);
+  EXPECT_NOT_POISONED(a[6]);
+  EXPECT_POISONED(a[7]);
+}
+
+TEST(MemorySanitizer, strncat_overflow) {  // NOLINT
+  char a[10];
+  char b[] = "def";
+  strcpy(a, "abc");
+  __msan_poison(b + 1, 1);
+  strncat(a, b, 2);
+  EXPECT_NOT_POISONED(a[3]);
+  EXPECT_POISONED(a[4]);
+  EXPECT_NOT_POISONED(a[5]);
+  EXPECT_POISONED(a[6]);
+  EXPECT_POISONED(a[7]);
+}
+
 TEST(MemorySanitizer, strtol) {
   char *e;
   assert(1 == strtol("1", &e, 10));