Commit 68ef8735 authored by Kees Cook's avatar Kees Cook Committed by Thomas Gleixner
Browse files

lkdtm: Add REPORT_STACK for checking stack offsets 



For validating the stack offset behavior, report the offset from a given
process's first seen stack address. Add s script to calculate the results
to the LKDTM kselftests.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210401232347.2791257-7-keescook@chromium.org
parent fe950f60

drivers/misc/lkdtm/bugs.c

+17 −0
Original line number Diff line number Diff line
@@ -134,6 +134,23 @@ noinline void lkdtm_CORRUPT_STACK_STRONG(void) 
	__lkdtm_CORRUPT_STACK((void *)&data);

}



static pid_t stack_pid;

static unsigned long stack_addr;



void lkdtm_REPORT_STACK(void)

{

	volatile uintptr_t magic;

	pid_t pid = task_pid_nr(current);



	if (pid != stack_pid) {

		pr_info("Starting stack offset tracking for pid %d\n", pid);

		stack_pid = pid;

		stack_addr = (uintptr_t)&magic;

	}



	pr_info("Stack offset: %d\n", (int)(stack_addr - (uintptr_t)&magic));

}



void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void)

{

	static u8 data[5] __attribute__((aligned(4))) = {1, 2, 3, 4, 5};

drivers/misc/lkdtm/core.c

+1 −0
Original line number Diff line number Diff line
@@ -110,6 +110,7 @@ static const struct crashtype crashtypes[] = { 
	CRASHTYPE(EXHAUST_STACK),

	CRASHTYPE(CORRUPT_STACK),

	CRASHTYPE(CORRUPT_STACK_STRONG),

	CRASHTYPE(REPORT_STACK),

	CRASHTYPE(CORRUPT_LIST_ADD),

	CRASHTYPE(CORRUPT_LIST_DEL),

	CRASHTYPE(STACK_GUARD_PAGE_LEADING),

drivers/misc/lkdtm/lkdtm.h

+1 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ void lkdtm_LOOP(void); 
void lkdtm_EXHAUST_STACK(void);

void lkdtm_CORRUPT_STACK(void);

void lkdtm_CORRUPT_STACK_STRONG(void);

void lkdtm_REPORT_STACK(void);

void lkdtm_UNALIGNED_LOAD_STORE_WRITE(void);

void lkdtm_SOFTLOCKUP(void);

void lkdtm_HARDLOCKUP(void);

tools/testing/selftests/lkdtm/.gitignore

+1 −0
Original line number Diff line number Diff line 
*.sh

!run.sh

!stack-entropy.sh

tools/testing/selftests/lkdtm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ include ../lib.mk 


# NOTE: $(OUTPUT) won't get default value if used before lib.mk

TEST_FILES := tests.txt

TEST_PROGS := stack-entropy.sh

TEST_GEN_PROGS = $(patsubst %,$(OUTPUT)/%.sh,$(shell awk '{print $$1}' tests.txt | sed -e 's/\#//'))

all: $(TEST_GEN_PROGS)