File: canary.c

package info (click to toggle)
llvm-toolchain-17 1%3A17.0.6-22
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 1,799,624 kB
  • sloc: cpp: 6,428,607; ansic: 1,383,196; asm: 793,408; python: 223,504; objc: 75,364; f90: 60,502; lisp: 33,869; pascal: 15,282; sh: 9,684; perl: 7,453; ml: 4,937; awk: 3,523; makefile: 2,889; javascript: 2,149; xml: 888; fortran: 619; cs: 573
file content (38 lines) | stat: -rw-r--r-- 1,040 bytes parent folder | download | duplicates (34) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
 
// RUN: %clang_safestack -fno-stack-protector -D_FORTIFY_SOURCE=0 -g %s -o %t.nossp
// RUN: %run %t.nossp 2>&1 | FileCheck --check-prefix=NOSSP %s

// RUN: %clang_safestack -fstack-protector-all -D_FORTIFY_SOURCE=0 -g %s -o %t.ssp
// RUN: env LIBC_FATAL_STDERR_=1 not --crash %run %t.ssp 2>&1 | \
// RUN:     FileCheck -check-prefix=SSP %s

// Test stack canaries on the unsafe stack.

// REQUIRES: stable-runtime

#include <assert.h>
#include <stdio.h>
#include <string.h>

__attribute__((noinline)) void f(unsigned *y) {
  char x;
  char *volatile p = &x;
  char *volatile q = (char *)y;
  assert(p < q);
  assert(q - p < 1024); // sanity
  // This has technically undefined behavior, but we know the actual layout of
  // the unsafe stack and this should not touch anything important.
  memset(&x, 0xab, q - p + sizeof(*y));
}

int main(int argc, char **argv)
{
  unsigned y;
  // NOSSP: main 1
  // SSP: main 1
  fprintf(stderr, "main 1\n");
  f(&y);
  // NOSSP: main 2
  // SSP-NOT: main 2
  fprintf(stderr, "main 2\n");
  return 0;
}