Commit 39538319 authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
Browse files

Merge tag 'lkdtm-v5.17-rc1' of... 

Merge tag 'lkdtm-v5.17-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into char-misc-next

Kees writes:

lkdtm updates for v5.17-rc1

- Fix printk() usage during recursion (Ard Biesheuvel)
- Fix rodata section to actually have contents (Christophe Leroy)
- Add notes about lkdtm_kernel_info usage (Kees Cook)
- Avoid stack-entropy selftest when LKDTM is disabled (Misono Tomohiro)

* tag 'lkdtm-v5.17-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  selftest/lkdtm: Skip stack-entropy test if lkdtm is not available
  lkdtm: Fix content of section containing lkdtm_rodata_do_nothing()
  lkdtm: avoid printk() in recursive_loop()
  lkdtm: Note that lkdtm_kernel_info should be removed in the future
parents af40d160 90091c36

drivers/misc/lkdtm/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -20,7 +20,7 @@ CFLAGS_REMOVE_rodata.o += $(CC_FLAGS_LTO) 


OBJCOPYFLAGS :=

OBJCOPYFLAGS_rodata_objcopy.o	:= \

			--rename-section .noinstr.text=.rodata,alloc,readonly,load

			--rename-section .noinstr.text=.rodata,alloc,readonly,load,contents

targets += rodata.o rodata_objcopy.o

$(obj)/rodata_objcopy.o: $(obj)/rodata.o FORCE

	$(call if_changed,objcopy)

drivers/misc/lkdtm/bugs.c

+9 −7
Original line number Diff line number Diff line
@@ -41,20 +41,22 @@ static DEFINE_SPINLOCK(lock_me_up); 
 * Make sure compiler does not optimize this function or stack frame away:

 * - function marked noinline

 * - stack variables are marked volatile

 * - stack variables are written (memset()) and read (pr_info())

 * - function has external effects (pr_info())

 * */

 * - stack variables are written (memset()) and read (buf[..] passed as arg)

 * - function may have external effects (memzero_explicit())

 * - no tail recursion possible

 */

static int noinline recursive_loop(int remaining)

{

	volatile char buf[REC_STACK_SIZE];

	volatile int ret;



	memset((void *)buf, remaining & 0xFF, sizeof(buf));

	pr_info("loop %d/%d ...\n", (int)buf[remaining % sizeof(buf)],

		recur_count);

	if (!remaining)

		return 0;

		ret = 0;

	else

		return recursive_loop(remaining - 1);

		ret = recursive_loop((int)buf[remaining % sizeof(buf)] - 1);

	memzero_explicit((void *)buf, sizeof(buf));

	return ret;

}



/* If the depth is negative, use the default, otherwise keep parameter. */

drivers/misc/lkdtm/core.c

+5 −1
Original line number Diff line number Diff line
@@ -212,7 +212,11 @@ module_param(cpoint_count, int, 0644); 
MODULE_PARM_DESC(cpoint_count, " Crash Point Count, number of times the "\

				"crash point is to be hit to trigger action");



/* For test debug reporting. */

/*

 * For test debug reporting when CI systems provide terse summaries.

 * TODO: Remove this once reasonable reporting exists in most CI systems:

 * https://lore.kernel.org/lkml/CAHk-=wiFvfkoFixTapvvyPMN9pq5G-+Dys2eSyBa1vzDGAO5+A@mail.gmail.com

 */

char *lkdtm_kernel_info;



/* Return the crashtype number or NULL if the name is invalid */

tools/testing/selftests/lkdtm/stack-entropy.sh

+15 −1
Original line number Diff line number Diff line
@@ -4,13 +4,27 @@ 
# Measure kernel stack entropy by sampling via LKDTM's REPORT_STACK test.

set -e

samples="${1:-1000}"

TRIGGER=/sys/kernel/debug/provoke-crash/DIRECT

KSELFTEST_SKIP_TEST=4



# Verify we have LKDTM available in the kernel.

if [ ! -r $TRIGGER ] ; then

	/sbin/modprobe -q lkdtm || true

	if [ ! -r $TRIGGER ] ; then

		echo "Cannot find $TRIGGER (missing CONFIG_LKDTM?)"

	else

		echo "Cannot write $TRIGGER (need to run as root?)"

	fi

	# Skip this test

	exit $KSELFTEST_SKIP_TEST

fi



# Capture dmesg continuously since it may fill up depending on sample size.

log=$(mktemp -t stack-entropy-XXXXXX)

dmesg --follow >"$log" & pid=$!

report=-1

for i in $(seq 1 $samples); do

        echo "REPORT_STACK" >/sys/kernel/debug/provoke-crash/DIRECT

        echo "REPORT_STACK" > $TRIGGER

	if [ -t 1 ]; then

		percent=$(( 100 * $i / $samples ))

		if [ "$percent" -ne "$report" ]; then