[asan] Correctly release memory allocated during early startup.

Calloc interceptor initially allocates memory from temp buffer (to serve dlsyms called during asan_init). There is a chance that some non-instrumented library (or executable) has allocated memory with calloc before asan_init and got pointer from the same temporary buffer which later caused problems with free.

Inspired by https://github.com/google/sanitizers/issues/626

Differential Revision: http://reviews.llvm.org/D14979


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@254395 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 0 deletions

diff --git a/test/asan/TestCases/Linux/calloc-preload.c b/test/asan/TestCases/Linux/calloc-preload.c
new file mode 100644
index 000000000..eb1c6738b
--- /dev/null
+++ b/test/asan/TestCases/Linux/calloc-preload.c
@@ -0,0 +1,36 @@
+// Test that initially callocked memory is properly freed
+// (see https://github.com/google/sanitizers/issues/626).
+// 
+// RUN: %clang %s -o %t
+// RUN: env LD_PRELOAD=%shared_libasan %run %t
+//
+// REQUIRES: asan-dynamic-runtime
+//
+// This way of setting LD_PRELOAD does not work with Android test runner.
+// REQUIRES: not-android
+
+#include <stdio.h>
+#include <stdlib.h>
+
+static void *ptr;
+
+// This constructor will run before __asan_init
+// so calloc will allocate memory from special pool.
+static void init() {
+  ptr = calloc(10, 1);
+}
+
+__attribute__((section(".preinit_array"), used))
+void *dummy = init;
+
+void free_memory() {
+  // This used to abort because
+  // Asan's free didn't recognize ptr.
+  free(ptr);
+}
+
+int main() {
+  free_memory();
+  return 0;
+}
+