[mirror_ubuntu-zesty-kernel.git] / arch / arm64 / include / asm / stackprotector.h

/*
 * GCC stack protector support.
 *
 * Stack protector works by putting predefined pattern at the start of
 * the stack frame and verifying that it hasn't been overwritten when
 * returning from the function.  The pattern is called stack canary
 * and gcc expects it to be defined by a global variable called
 * "__stack_chk_guard" on ARM.  This unfortunately means that on SMP
 * we cannot have a different canary value per task.
 */

#ifndef __ASM_STACKPROTECTOR_H
#define __ASM_STACKPROTECTOR_H

#include <linux/random.h>
#include <linux/version.h>

extern unsigned long __stack_chk_guard;

/*
 * Initialize the stackprotector canary value.
 *
 * NOTE: this must only be called from functions that never return,
 * and it must always be inlined.
 */
static __always_inline void boot_init_stack_canary(void)
{
	unsigned long canary;

	/* Try to get a semi random initial value. */
	get_random_bytes(&canary, sizeof(canary));
	canary ^= LINUX_VERSION_CODE;

	current->stack_canary = canary;
	__stack_chk_guard = current->stack_canary;
}

#endif	/* _ASM_STACKPROTECTOR_H */
Commit	Line	Data
c0c264ae LA	1	/*
	2	* GCC stack protector support.
	3	*
	4	* Stack protector works by putting predefined pattern at the start of
	5	* the stack frame and verifying that it hasn't been overwritten when
	6	* returning from the function. The pattern is called stack canary
	7	* and gcc expects it to be defined by a global variable called
	8	* "__stack_chk_guard" on ARM. This unfortunately means that on SMP
	9	* we cannot have a different canary value per task.
	10	*/
	11
	12	#ifndef __ASM_STACKPROTECTOR_H
	13	#define __ASM_STACKPROTECTOR_H
	14
	15	#include <linux/random.h>
	16	#include <linux/version.h>
	17
	18	extern unsigned long __stack_chk_guard;
	19
	20	/*
	21	* Initialize the stackprotector canary value.
	22	*
	23	* NOTE: this must only be called from functions that never return,
	24	* and it must always be inlined.
	25	*/
	26	static __always_inline void boot_init_stack_canary(void)
	27	{
	28	unsigned long canary;
	29
	30	/* Try to get a semi random initial value. */
	31	get_random_bytes(&canary, sizeof(canary));
	32	canary ^= LINUX_VERSION_CODE;
	33
	34	current->stack_canary = canary;
	35	__stack_chk_guard = current->stack_canary;
	36	}
	37
	38	#endif /* _ASM_STACKPROTECTOR_H */