newlib/libc/ssp/stack_protector.c

   1 #include <sys/cdefs.h>
   2 #include <sys/param.h>
   3 #include <signal.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #include <unistd.h>
   7
   8 #if defined(__AMDGCN__) || defined(__nvptx__)
   9 /* Global constructors not supported on this target, yet.  */
  10 uintptr_t __stack_chk_guard = 0x00000aff; /* 0, 0, '\n', 255  */
  11
  12 #else
  13 uintptr_t __stack_chk_guard = 0;
  14
  15 void
  16 __attribute__((__constructor__))
  17 __stack_chk_init (void)
  18 {
  19   if (__stack_chk_guard != 0)
  20     return;
  21
  22 #if defined(__CYGWIN__) || defined(__rtems__)
  23   arc4random_buf(&__stack_chk_guard, sizeof(__stack_chk_guard));
  24 #else
  25   /* If getentropy is not available, use the "terminator canary". */
  26   ((unsigned char *)&__stack_chk_guard)[0] = 0;
  27   ((unsigned char *)&__stack_chk_guard)[1] = 0;
  28   ((unsigned char *)&__stack_chk_guard)[2] = '\n';
  29   ((unsigned char *)&__stack_chk_guard)[3] = 255;
  30 #endif
  31 }
  32 #endif
  33
  34 void
  35 __attribute__((__noreturn__))
  36 __stack_chk_fail (void)
  37 {
  38   char msg[] = "*** stack smashing detected ***: terminated\n";
  39   write (2, msg, strlen (msg));
  40   raise (SIGABRT);
  41   _exit (127);
  42 }
  43
  44 #ifdef __ELF__
  45 void
  46 __attribute__((visibility ("hidden")))
  47 __stack_chk_fail_local (void)
  48 {
  49         __stack_chk_fail();
  50 }
  51 #endif