[sanitizer] Handle malloc_destroy_zone() on Darwin

We currently have a interceptor for malloc_create_zone, which returns a new zone that redirects all the zone requests to our sanitizer zone. However, calling malloc_destroy_zone on that zone will cause libmalloc to print out some warning messages, because the zone is not registered in the list of zones. This patch handles this and adds a testcase for that.

Differential Revision: https://reviews.llvm.org/D27083

llvm-svn: 289375

2 files changed, 34 insertions, 0 deletions

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_malloc_mac.inc b/compiler-rt/lib/sanitizer_common/sanitizer_malloc_mac.inc
index 149857c168c..caf753ad2f5 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_malloc_mac.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_malloc_mac.inc
@@ -46,9 +46,22 @@ INTERCEPTOR(malloc_zone_t *, malloc_create_zone,
     // This matches the behavior of malloc_create_zone() on OSX 10.7 and higher.
     mprotect(new_zone, allocated_size, PROT_READ);
   }
+  // We're explicitly *NOT* registering the zone.
   return new_zone;
 }
 
+INTERCEPTOR(void, malloc_destroy_zone, malloc_zone_t *zone) {
+  COMMON_MALLOC_ENTER();
+  // We don't need to do anything here.  We're not registering new zones, so we
+  // don't to unregister.  Just un-mprotect and free() the zone.
+  if (GetMacosVersion() >= MACOS_VERSION_LION) {
+    uptr page_size = GetPageSizeCached();
+    uptr allocated_size = RoundUpTo(sizeof(sanitizer_zone), page_size);
+    mprotect(zone, allocated_size, PROT_READ | PROT_WRITE);
+  }
+  COMMON_MALLOC_FREE(zone);
+}
+
 INTERCEPTOR(malloc_zone_t *, malloc_default_zone, void) {
   COMMON_MALLOC_ENTER();
   return &sanitizer_zone;
diff --git a/compiler-rt/test/asan/TestCases/Darwin/malloc_destroy_zone.cc b/compiler-rt/test/asan/TestCases/Darwin/malloc_destroy_zone.cc
new file mode 100644
index 00000000000..9144bd689f7
--- /dev/null
+++ b/compiler-rt/test/asan/TestCases/Darwin/malloc_destroy_zone.cc
@@ -0,0 +1,21 @@
+// RUN: %clangxx_asan %s -o %t && %run %t 2>&1 | FileCheck %s
+
+#include <malloc/malloc.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+int main() {
+  fprintf(stderr, "start\n");
+  malloc_zone_t *zone = malloc_create_zone(0, 0);
+  fprintf(stderr, "zone = %p\n", zone);
+  malloc_set_zone_name(zone, "myzone");
+  fprintf(stderr, "name changed\n");
+  malloc_destroy_zone(zone);
+  fprintf(stderr, "done\n");
+  return 0;
+}
+
+// CHECK: start
+// CHECK-NEXT: zone = 0x{{.*}}
+// CHECK-NEXT: name changed
+// CHECK-NEXT: done