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: env LIBC_FATAL_STDERR_=1 not --crash %run %t.ssp 2>&1 | \
   6 // RUN:     FileCheck -check-prefix=SSP %s
   7
   8 // Test stack canaries on the unsafe stack.
   9
  10 // REQUIRES: stable-runtime
  11
  12 #include <assert.h>
  13 #include <stdio.h>
  14 #include <string.h>
  15
  16 __attribute__((noinline)) void f(unsigned *y) {
  17   char x;
  18   char *volatile p = &x;
  19   char *volatile q = (char *)y;
  20   assert(p < q);
  21   assert(q - p < 1024); // sanity
  22   // This has technically undefined behavior, but we know the actual layout of
  23   // the unsafe stack and this should not touch anything important.
  24   memset(&x, 0xab, q - p + sizeof(*y));
  25 }
  26
  27 int main(int argc, char **argv)
  28 {
  29   unsigned y;
  30   // NOSSP: main 1
  31   // SSP: main 1
  32   fprintf(stderr, "main 1\n");
  33   f(&y);
  34   // NOSSP: main 2
  35   // SSP-NOT: main 2
  36   fprintf(stderr, "main 2\n");
  37   return 0;
  38 }