1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _LINUX_STACKPROTECTOR_H 3#define _LINUX_STACKPROTECTOR_H 1 4 5#include <linux/compiler.h> 6#include <linux/sched.h> 7#include <linux/random.h> 8 9/* 10 * On 64-bit architectures, protect against non-terminated C string overflows 11 * by zeroing out the first byte of the canary; this leaves 56 bits of entropy. 12 */ 13#ifdef CONFIG_64BIT 14# ifdef __LITTLE_ENDIAN 15# define CANARY_MASK 0xffffffffffffff00UL 16# else /* big endian, 64 bits: */ 17# define CANARY_MASK 0x00ffffffffffffffUL 18# endif 19#else /* 32 bits: */ 20# define CANARY_MASK 0xffffffffUL 21#endif 22 23static inline unsigned long get_random_canary(void) 24{ 25 return get_random_long() & CANARY_MASK; 26} 27 28#if defined(CONFIG_STACKPROTECTOR) || defined(CONFIG_ARM64_PTR_AUTH) 29# include <asm/stackprotector.h> 30#else 31static inline void boot_init_stack_canary(void) 32{ 33} 34#endif 35 36#endif 37