LXR linux/arch/mips/include/asm/stackprotector.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * GCC stack protector support.
   4 *
   5 * (This is directly adopted from the ARM implementation)
   6 *
   7 * Stack protector works by putting predefined pattern at the start of
   8 * the stack frame and verifying that it hasn't been overwritten when
   9 * returning from the function.  The pattern is called stack canary
  10 * and gcc expects it to be defined by a global variable called
  11 * "__stack_chk_guard" on MIPS.  This unfortunately means that on SMP
  12 * we cannot have a different canary value per task.
  13 */
  14
  15#ifndef _ASM_STACKPROTECTOR_H
  16#define _ASM_STACKPROTECTOR_H 1
  17
  18#include <linux/random.h>
  19#include <linux/version.h>
  20
  21extern unsigned long __stack_chk_guard;
  22
  23/*
  24 * Initialize the stackprotector canary value.
  25 *
  26 * NOTE: this must only be called from functions that never return,
  27 * and it must always be inlined.
  28 */
  29static __always_inline void boot_init_stack_canary(void)
  30{
  31        unsigned long canary;
  32
  33        /* Try to get a semi random initial value. */
  34        get_random_bytes(&canary, sizeof(canary));
  35        canary ^= LINUX_VERSION_CODE;
  36
  37        current->stack_canary = canary;
  38        __stack_chk_guard = current->stack_canary;
  39}
  40
  41#endif  /* _ASM_STACKPROTECTOR_H */
  42