[ASan] Do not check the shadow of NULL argument in the time() interceptor.

Add a test for time().

llvm-svn: 179177

2 files changed, 21 insertions, 1 deletions

diff --git a/compiler-rt/lib/asan/lit_tests/time_interceptor.cc b/compiler-rt/lib/asan/lit_tests/time_interceptor.cc
new file mode 100644
index 00000000000..bade7bbc687
--- /dev/null
+++ b/compiler-rt/lib/asan/lit_tests/time_interceptor.cc
@@ -0,0 +1,20 @@
+// RUN: %clangxx_asan -m64 -O0 %s -fsanitize-address-zero-base-shadow -pie -o %t && %t 2>&1 | %symbolize | FileCheck %s
+
+// Test the time() interceptor. Also includes a regression test for time(NULL),
+// which caused ASan to crash in the zero-based shadow mode.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+int main() {
+  time_t *tm = (time_t*)malloc(sizeof(time_t));
+  free(tm);
+  time_t t = time(NULL);
+  fprintf(stderr, "Time: %s\n", ctime(&t));
+  // CHECK: {{Time: .* .* .*}}
+  t = time(tm);
+  printf("Time: %s\n", ctime(&t));
+  // CHECK: use-after-free
+  return 0;
+}
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
index 18ff952dfa1..43e5a6df355 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -236,7 +236,7 @@ INTERCEPTOR(unsigned long, time, unsigned long *t) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, time, t);
   unsigned long res = REAL(time)(t);
-  if (res != (unsigned long)-1) {
+  if (t && res != (unsigned long)-1) {
     COMMON_INTERCEPTOR_WRITE_RANGE(ctx, t, sizeof(*t));
   }
   return res;