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Commit aac416fc authored by Kees Cook's avatar Kees Cook Committed by Greg Kroah-Hartman
Browse files

lkdtm: flush icache and report actions 



Some CPUs explicitly need to have their icache flushed after making
executable code copies for the memory region execution tests.
Additionally, report the specific address targets being used so that
debugging non-crash failures is easier.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent feac6e21

drivers/misc/lkdtm.c

+16 −0
Original line number Diff line number Diff line
@@ -329,7 +329,12 @@ static void execute_location(void *dst) 
{

	void (*func)(void) = dst;



	pr_info("attempting ok execution at %p\n", do_nothing);

	do_nothing();



	memcpy(dst, do_nothing, EXEC_SIZE);

	flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);

	pr_info("attempting bad execution at %p\n", func);

	func();

}
@@ -338,8 +343,13 @@ static void execute_user_location(void *dst) 
	/* Intentionally crossing kernel/user memory boundary. */

	void (*func)(void) = dst;



	pr_info("attempting ok execution at %p\n", do_nothing);

	do_nothing();



	if (copy_to_user((void __user *)dst, do_nothing, EXEC_SIZE))

		return;

	flush_icache_range((unsigned long)dst, (unsigned long)dst + EXEC_SIZE);

	pr_info("attempting bad execution at %p\n", func);

	func();

}
@@ -464,8 +474,12 @@ static void lkdtm_do_action(enum ctype which) 
		}



		ptr = (unsigned long *)user_addr;



		pr_info("attempting bad read at %p\n", ptr);

		tmp = *ptr;

		tmp += 0xc0dec0de;



		pr_info("attempting bad write at %p\n", ptr);

		*ptr = tmp;



		vm_munmap(user_addr, PAGE_SIZE);
@@ -476,6 +490,8 @@ static void lkdtm_do_action(enum ctype which) 
		unsigned long *ptr;



		ptr = (unsigned long *)&rodata;



		pr_info("attempting bad write at %p\n", ptr);

		*ptr ^= 0xabcd1234;



		break;