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Commit aa92db14 authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Ingo Molnar
Browse files

stackprotector: better self-test 



check stackprotector functionality by manipulating the canary briefly
during bootup.

far more robust than trying to overflow the stack. (which is architecture
dependent, etc.)

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 5ce001b0

kernel/panic.c

+5 −8
Original line number Diff line number Diff line
@@ -347,22 +347,18 @@ static noinline void __stack_chk_test_func(void) 
	if ((unsigned long)__builtin_return_address(0) ==

					*(((unsigned long *)&foo)+1)) {

		printk(KERN_ERR "No -fstack-protector-stack-frame!\n");

		return;

	}

#ifdef CONFIG_FRAME_POINTER

	/* We also don't want to clobber the frame pointer */

	if ((unsigned long)__builtin_return_address(0) ==

					*(((unsigned long *)&foo)+2)) {

		printk(KERN_ERR "No -fstack-protector-stack-frame!\n");

		return;

	}

#endif

	barrier();

	if (current->stack_canary == *(((unsigned long *)&foo)+1))

		*(((unsigned long *)&foo)+1) = 0;

	else

	if (current->stack_canary != *(((unsigned long *)&foo)+1))

		printk(KERN_ERR "No -fstack-protector canary found\n");

	barrier();



	current->stack_canary = ~current->stack_canary;

}



static int __stack_chk_test(void)
@@ -373,7 +369,8 @@ static int __stack_chk_test(void) 
	if (__stack_check_testing) {

		printk(KERN_ERR "-fstack-protector-all test failed\n");

		WARN_ON(1);

	}

	};

	current->stack_canary = ~current->stack_canary;

	return 0;

}

/*