Commit 09f33601 authored by Huacai Chen's avatar Huacai Chen
Browse files

LoongArch: Add basic STACKPROTECTOR support 



Add basic stack protector support similar to other architectures. A
constant canary value is set at boot time, and with help of compiler's
-fstack-protector we can detect stack corruption.

Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent 7db54bfe

arch/loongarch/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -103,6 +103,7 @@ config LOONGARCH 
	select HAVE_REGS_AND_STACK_ACCESS_API

	select HAVE_RSEQ

	select HAVE_SETUP_PER_CPU_AREA if NUMA

	select HAVE_STACKPROTECTOR

	select HAVE_SYSCALL_TRACEPOINTS

	select HAVE_TIF_NOHZ

	select HAVE_VIRT_CPU_ACCOUNTING_GEN if !SMP

arch/loongarch/include/asm/stackprotector.h

0 → 100644
+38 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

/*

 * 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

 * on LoongArch gcc expects it to be defined by a global variable called

 * "__stack_chk_guard".

 */



#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 */

arch/loongarch/kernel/asm-offsets.c

+3 −0
Original line number Diff line number Diff line
@@ -68,6 +68,9 @@ void output_task_defines(void) 
	OFFSET(TASK_FLAGS, task_struct, flags);

	OFFSET(TASK_MM, task_struct, mm);

	OFFSET(TASK_PID, task_struct, pid);

#if defined(CONFIG_STACKPROTECTOR)

	OFFSET(TASK_STACK_CANARY, task_struct, stack_canary);

#endif

	DEFINE(TASK_STRUCT_SIZE, sizeof(struct task_struct));

	BLANK();

}

arch/loongarch/kernel/process.c

+6 −0
Original line number Diff line number Diff line
@@ -47,6 +47,12 @@ 
#include <asm/unwind.h>

#include <asm/vdso.h>



#ifdef CONFIG_STACKPROTECTOR

#include <linux/stackprotector.h>

unsigned long __stack_chk_guard __read_mostly;

EXPORT_SYMBOL(__stack_chk_guard);

#endif



/*

 * Idle related variables and functions

 */

arch/loongarch/kernel/switch.S

+5 −0
Original line number Diff line number Diff line
@@ -23,6 +23,11 @@ SYM_FUNC_START(__switch_to) 
	stptr.d	ra, a0, THREAD_REG01

	stptr.d a3, a0, THREAD_SCHED_RA

	stptr.d a4, a0, THREAD_SCHED_CFA

#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_SMP)

	la	t7, __stack_chk_guard

	LONG_L	t8, a1, TASK_STACK_CANARY

	LONG_S	t8, t7, 0

#endif

	move	tp, a2

	cpu_restore_nonscratch a1