src/libcompiler_builtins/compiler-rt/test/asan/TestCases/Linux/longjmp_chk.c

   1 // Verify that use of longjmp() in a _FORTIFY_SOURCE'd library (without ASAN)
   2 // is correctly intercepted such that the stack is unpoisoned.
   3 // Note: it is essential that the external library is not built with ASAN,
   4 // otherwise it would be able to unpoison the stack before use.
   5 //
   6 // RUN: %clang -DIS_LIBRARY -D_FORTIFY_SOURCE=2 -O2 %s -c -o %t.o
   7 // RUN: %clang_asan -O2 %s %t.o -o %t
   8 // RUN: %run %t
   9
  10 #ifdef IS_LIBRARY
  11 /* the library */
  12 #include <setjmp.h>
  13 #include <assert.h>
  14 #include <sanitizer/asan_interface.h>
  15
  16 static jmp_buf jenv;
  17
  18 void external_callme(void (*callback)(void)) {
  19   if (setjmp(jenv) == 0) {
  20     callback();
  21   }
  22 }
  23
  24 void external_longjmp(char *msg) {
  25   longjmp(jenv, 1);
  26 }
  27
  28 void external_check_stack(void) {
  29   char buf[256] = "";
  30   for (int i = 0; i < 256; i++) {
  31     assert(!__asan_address_is_poisoned(buf + i));
  32   }
  33 }
  34 #else
  35 /* main program */
  36 extern void external_callme(void (*callback)(void));
  37 extern void external_longjmp(char *msg);
  38 extern void external_check_stack(void);
  39
  40 static void callback(void) {
  41   char msg[16];   /* Note: this triggers addition of a redzone. */
  42   /* Note: msg is passed to prevent compiler optimization from removing it. */
  43   external_longjmp(msg);
  44 }
  45
  46 int main() {
  47   external_callme(callback);
  48   external_check_stack();
  49   return 0;
  50 }
  51 #endif