src/env/__stack_chk_fail.c

   1 #include <string.h>
   2 #include <stdint.h>
   3 #include "pthread_impl.h"
   4
   5 uintptr_t __stack_chk_guard;
   6
   7 void __init_ssp(void *entropy)
   8 {
   9         if (entropy) memcpy(&__stack_chk_guard, entropy, sizeof(uintptr_t));
  10         else __stack_chk_guard = (uintptr_t)&__stack_chk_guard * 1103515245;
  11
  12 #if UINTPTR_MAX >= 0xffffffffffffffff
  13         /* Sacrifice 8 bits of entropy on 64bit to prevent leaking/
  14          * overwriting the canary via string-manipulation functions.
  15          * The NULL byte is on the second byte so that off-by-ones can
  16          * still be detected. Endianness is taken care of
  17          * automatically. */
  18         ((char *)&__stack_chk_guard)[1] = 0;
  19 #endif
  20
  21         __pthread_self()->canary = __stack_chk_guard;
  22 }
  23
  24 void __stack_chk_fail(void)
  25 {
  26         a_crash();
  27 }
  28
  29 hidden void __stack_chk_fail_local(void);
  30
  31 weak_alias(__stack_chk_fail, __stack_chk_fail_local);