[llvm-commits] [compiler-rt] r150101 - in /compiler-rt/trunk/lib/asan: asan_interceptors.cc asan_interface.h asan_rtl.cc tests/clone_test.cc tests/clone_test.tmpl

[Kostya Serebryany]

Author: kcc
Date: Wed Feb  8 15:33:27 2012
New Revision: 150101

URL: http://llvm.org/viewvc/llvm-project?rev=150101&view=rev
Log:
[asan] unpoison the stack before every noreturn call. Fixes asan issue 37. rt part

Added:
    compiler-rt/trunk/lib/asan/tests/clone_test.cc
    compiler-rt/trunk/lib/asan/tests/clone_test.tmpl
Modified:
    compiler-rt/trunk/lib/asan/asan_interceptors.cc
    compiler-rt/trunk/lib/asan/asan_interface.h
    compiler-rt/trunk/lib/asan/asan_rtl.cc

Modified: compiler-rt/trunk/lib/asan/asan_interceptors.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_interceptors.cc?rev=150101&r1=150100&r2=150101&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_interceptors.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_interceptors.cc Wed Feb  8 15:33:27 2012
@@ -231,28 +231,18 @@
 }
 #endif  // _WIN32
 
-
-static void UnpoisonStackFromHereToTop() {
-  int local_stack;
-  AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
-  CHECK(curr_thread);
-  uintptr_t top = curr_thread->stack_top();
-  uintptr_t bottom = ((uintptr_t)&local_stack - kPageSize) & ~(kPageSize-1);
-  PoisonShadow(bottom, top - bottom, 0);
-}
-
 INTERCEPTOR(void, longjmp, void *env, int val) {
-  UnpoisonStackFromHereToTop();
+  __asan_handle_no_return();
   REAL(longjmp)(env, val);
 }
 
 INTERCEPTOR(void, _longjmp, void *env, int val) {
-  UnpoisonStackFromHereToTop();
+  __asan_handle_no_return();
   REAL(_longjmp)(env, val);
 }
 
 INTERCEPTOR(void, siglongjmp, void *env, int val) {
-  UnpoisonStackFromHereToTop();
+  __asan_handle_no_return();
   REAL(siglongjmp)(env, val);
 }
 
@@ -263,7 +253,7 @@
 
 INTERCEPTOR(void, __cxa_throw, void *a, void *b, void *c) {
   CHECK(REAL(__cxa_throw));
-  UnpoisonStackFromHereToTop();
+  __asan_handle_no_return();
   REAL(__cxa_throw)(a, b, c);
 }
 #endif

Modified: compiler-rt/trunk/lib/asan/asan_interface.h
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_interface.h?rev=150101&r1=150100&r2=150101&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_interface.h (original)
+++ compiler-rt/trunk/lib/asan/asan_interface.h Wed Feb  8 15:33:27 2012
@@ -79,6 +79,10 @@
   // (un)poison memory in the same memory region simultaneously.
   void __asan_unpoison_memory_region(void const volatile *addr, size_t size);
 
+  // Performs cleanup before a NoReturn function. Must be called before things
+  // like _exit and execl to avoid false positives on stack.
+  void __asan_handle_no_return();
+
 // User code should use macro instead of functions.
 #if defined(__has_feature) && __has_feature(address_sanitizer)
 #define ASAN_POISON_MEMORY_REGION(addr, size) \

Modified: compiler-rt/trunk/lib/asan/asan_rtl.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_rtl.cc?rev=150101&r1=150100&r2=150101&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_rtl.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_rtl.cc Wed Feb  8 15:33:27 2012
@@ -283,6 +283,15 @@
   return old;
 }
 
+void __asan_handle_no_return() {
+  int local_stack;
+  AsanThread *curr_thread = asanThreadRegistry().GetCurrent();
+  CHECK(curr_thread);
+  uintptr_t top = curr_thread->stack_top();
+  uintptr_t bottom = ((uintptr_t)&local_stack - kPageSize) & ~(kPageSize-1);
+  PoisonShadow(bottom, top - bottom, 0);
+}
+
 void __asan_report_error(uintptr_t pc, uintptr_t bp, uintptr_t sp,
                          uintptr_t addr, bool is_write, size_t access_size) {
   // Do not print more than one report, otherwise they will mix up.

Added: compiler-rt/trunk/lib/asan/tests/clone_test.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/tests/clone_test.cc?rev=150101&view=auto
==============================================================================
--- compiler-rt/trunk/lib/asan/tests/clone_test.cc (added)
+++ compiler-rt/trunk/lib/asan/tests/clone_test.cc Wed Feb  8 15:33:27 2012
@@ -0,0 +1,33 @@
+#ifdef __linux__
+#include <stdio.h>
+#include <sched.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+int Child(void *arg) {
+  char x[32] = {0};  // Stack gets poisoned.
+  printf("Child:  %p\n", x);
+  _exit(1);  // NoReturn, stack will remain unpoisoned unless we do something.
+}
+
+int main(int argc, char **argv) {
+  const int kStackSize = 1 << 20;
+  char child_stack[kStackSize + 1];
+  char *sp = child_stack + kStackSize;  // Stack grows down.
+  printf("Parent: %p\n", sp);
+  pid_t clone_pid = clone(Child, sp, CLONE_FILES | CLONE_VM, NULL, 0, 0, 0);
+  waitpid(clone_pid, NULL, 0);
+  for (int i = 0; i < kStackSize; i++)
+    child_stack[i] = i;
+  int ret = child_stack[argc - 1];
+  printf("PASSED\n");
+  return ret;
+}
+#else  // not __linux__
+#include <stdio.h>
+int main() {
+  printf("PASSED\n");
+}
+#endif

Added: compiler-rt/trunk/lib/asan/tests/clone_test.tmpl
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/tests/clone_test.tmpl?rev=150101&view=auto
==============================================================================
--- compiler-rt/trunk/lib/asan/tests/clone_test.tmpl (added)
+++ compiler-rt/trunk/lib/asan/tests/clone_test.tmpl Wed Feb  8 15:33:27 2012
@@ -0,0 +1 @@
+PASSED