src/compiler-rt/test/safestack/canary.c

   1 // RUN: %clang_safestack -fno-stack-protector -D_FORTIFY_SOURCE=0 -g %s -o %t.nossp
   2 // RUN: %run %t.nossp 2>&1 | FileCheck --check-prefix=NOSSP %s
   3
   4 // RUN: %clang_safestack -fstack-protector-all -D_FORTIFY_SOURCE=0 -g %s -o %t.ssp
   5 // RUN: not --crash %run %t.ssp 2>&1 | FileCheck -check-prefix=SSP %s
   6
   7 // Test stack canaries on the unsafe stack.
   8
   9 // REQUIRES: stable-runtime
  10
  11 #include <assert.h>
  12 #include <stdio.h>
  13 #include <string.h>
  14
  15 __attribute__((noinline)) void f(unsigned *y) {
  16   char x;
  17   char *volatile p = &x;
  18   char *volatile q = (char *)y;
  19   assert(p < q);
  20   assert(q - p < 1024); // sanity
  21   // This has technically undefined behavior, but we know the actual layout of
  22   // the unsafe stack and this should not touch anything important.
  23   memset(&x, 0xab, q - p + sizeof(*y));
  24 }
  25
  26 int main(int argc, char **argv)
  27 {
  28   unsigned y;
  29   // NOSSP: main 1
  30   // SSP: main 1
  31   fprintf(stderr, "main 1\n");
  32   f(&y);
  33   // NOSSP: main 2
  34   // SSP-NOT: main 2
  35   fprintf(stderr, "main 2\n");
  36   return 0;
  37 }