sys/OpenBSD/stack_protector.c.patch

   1 Index: stack_protector.c
   2 ===================================================================
   3 --- stack_protector.c   (revision 31377)
   4 +++ stack_protector.c   (working copy)
   5 @@ -32,44 +32,41 @@ static char rcsid[] = "$OpenBSD: stack_p
   6  #include <sys/param.h>
   7  #include <sys/sysctl.h>
   8  #include <syslog.h>
   9 +#include <sys/types.h>
  10 +#include <unistd.h>
  11 +#include <fcntl.h>
  12 +
  13 +extern void __abort(void) __dead2;
  14 +long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
  15 +void __guard_setup(void) __attribute__ ((visibility ("hidden")));
  16 +void __stack_chk_fail(void);
  17
  18 -long __guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
  19 -static void __guard_setup(void) __attribute__ ((constructor));
  20 -void __stack_smash_handler(char func[], int damaged __attribute__((unused)));
  21 -
  22 -static void
  23 +void
  24  __guard_setup(void)
  25  {
  26    int fd;
  27 -  if (__guard[0]!=0) return;
  28 +  if (__stack_chk_guard[0]!=0) return;
  29    fd = open ("/dev/urandom", 0);
  30    if (fd != -1) {
  31 -    ssize_t size = read (fd, (char*)&__guard, sizeof(__guard));
  32 +    ssize_t size = read (fd, (char*)&__stack_chk_guard,
  33 +                        sizeof(__stack_chk_guard));
  34      close (fd) ;
  35 -    if (size == sizeof(__guard)) return;
  36 +    if (size == sizeof(__stack_chk_guard)
  37 +       && *__stack_chk_guard != 0) return;
  38    }
  39    /* If a random generator can't be used, the protector switches the guard
  40       to the "terminator canary" */
  41 -  ((char*)__guard)[0] = 0; ((char*)__guard)[1] = 0;
  42 -  ((char*)__guard)[2] = '\n'; ((char*)__guard)[3] = 255;
  43 +  ((char*)__stack_chk_guard)[0] = 0; ((char*)__stack_chk_guard)[1] = 0;
  44 +  ((char*)__stack_chk_guard)[2] = '\n'; ((char*)__stack_chk_guard)[3] = 255;
  45  }
  46
  47  void
  48 -__stack_smash_handler(char func[], int damaged)
  49 +__stack_chk_fail()
  50  {
  51 -  const char message[] = "stack overflow in function %s";
  52 -  struct sigaction sa;
  53 +  const char message[] = "[%d] stack overflow";
  54
  55    /* this may fail on a chroot jail, though luck */
  56 -  syslog(LOG_CRIT, message, func);
  57 -
  58 -  bzero(&sa, sizeof(struct sigaction));
  59 -  sigemptyset(&sa.sa_mask);
  60 -  sa.sa_flags = 0;
  61 -  sa.sa_handler = SIG_DFL;
  62 -  sigaction(SIGABRT, &sa, NULL);
  63 -
  64 -  kill(getpid(), SIGABRT);
  65 +  syslog(LOG_CRIT, message, getpid());
  66
  67 -  _exit(127);
  68 +  __abort();
  69  }