[PATCH] D40053: [asan] Don't crash on fclose(NULL)

[Kuba (Brecka) Mracek via Phabricator via llvm-commits]

kubamracek created this revision.
kubamracek added a project: Sanitizers.

It's explicitly forbidden to call `fclose` with `NULL`, but at least on Darwin, this succeeds and doesn't segfault. To maintain binary compatibility, ASan should survice `fclose(NULL)` as well.


Repository:
  rL LLVM

https://reviews.llvm.org/D40053

Files:
  lib/sanitizer_common/sanitizer_common_interceptors.inc
  test/asan/TestCases/Darwin/fclose.c


Index: test/asan/TestCases/Darwin/fclose.c
===================================================================
--- test/asan/TestCases/Darwin/fclose.c
+++ test/asan/TestCases/Darwin/fclose.c
@@ -0,0 +1,13 @@
+// RUN: %clang_asan %s -o %t
+// RUN: %run %t 2>&1 | FileCheck %s
+
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, const char * argv[]) {
+  fclose(NULL);
+  fprintf(stderr, "Finished.\n");
+  return 0;
+}
+
+// CHECK: Finished.
Index: lib/sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -273,7 +273,7 @@
   MetadataHashMap::Handle h(interceptor_metadata_map, (uptr)addr,
                             /* remove */ false,
                             /* create */ false);
-  if (h.exists()) {
+  if (addr && h.exists()) {
     CHECK(!h.created());
     CHECK(h->type == CommonInterceptorMetadata::CIMT_FILE);
     return &h->file;


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