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Commit 18aa8bb1 authored by Ingo Molnar's avatar Ingo Molnar Committed by Thomas Gleixner
Browse files

stackprotector: add boot_init_stack_canary() 



add the boot_init_stack_canary() and make the secondary idle threads
use it.

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 9b5609fd

arch/x86/kernel/process_64.c

+2 −4
Original line number Diff line number Diff line
@@ -147,7 +147,6 @@ void cpu_idle(void) 
{

	current_thread_info()->status |= TS_POLLING;



#ifdef CONFIG_CC_STACKPROTECTOR

	/*

	 * If we're the non-boot CPU, nothing set the PDA stack

	 * canary up for us - and if we are the boot CPU we have
@@ -156,9 +155,8 @@ void cpu_idle(void) 
	 * invalid canaries already on the stack wont ever

	 * trigger):

	 */

	current->stack_canary = get_random_int();

	write_pda(stack_canary, current->stack_canary);

#endif

	boot_init_stack_canary();



	/* endless idle loop with no priority at all */

	while (1) {

		tick_nohz_stop_sched_tick();

include/asm-x86/stackprotector.h

+20 −0
Original line number Diff line number Diff line 
#ifndef _ASM_STACKPROTECTOR_H

#define _ASM_STACKPROTECTOR_H 1



/*

 * 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)

{

	/*

	 * If we're the non-boot CPU, nothing set the PDA stack

	 * canary up for us - and if we are the boot CPU we have

	 * a 0 stack canary. This is a good place for updating

	 * it, as we wont ever return from this function (so the

	 * invalid canaries already on the stack wont ever

	 * trigger):

	 */

	current->stack_canary = get_random_int();

	write_pda(stack_canary, current->stack_canary);

}



#endif

include/linux/stackprotector.h

+4 −0
Original line number Diff line number Diff line
@@ -3,6 +3,10 @@ 


#ifdef CONFIG_CC_STACKPROTECTOR

# include <asm/stackprotector.h>

#else

static inline void boot_init_stack_canary(void)

{

}

#endif



#endif