Re: [PATCH v2] selftests/lkdtm: Add tests for LKDTM targets

On 12/30/19 3:57 PM, Kees Cook wrote:

This adds a basic framework for running all the "safe" LKDTM tests. This will allow easy introspection into any selftest logs to examine the results of most LKDTM tests.

Signed-off-by: Kees Cook keescook@chromium.org

v2: refreshed for v5.5, added new tests since v1 v1: https://lore.kernel.org/lkml/201905091013.E228F0F0BE@keescook/

---

MAINTAINERS | 1 + tools/testing/selftests/Makefile | 1 + tools/testing/selftests/lkdtm/Makefile | 12 ++++ tools/testing/selftests/lkdtm/config | 1 + tools/testing/selftests/lkdtm/run.sh | 91 +++++++++++++++++++++++++ tools/testing/selftests/lkdtm/tests.txt | 70 +++++++++++++++++++ 6 files changed, 176 insertions(+) create mode 100644 tools/testing/selftests/lkdtm/Makefile create mode 100644 tools/testing/selftests/lkdtm/config create mode 100755 tools/testing/selftests/lkdtm/run.sh create mode 100644 tools/testing/selftests/lkdtm/tests.txt

diff --git a/MAINTAINERS b/MAINTAINERS index cc0a4a8ae06a..eacc00c6cfd5 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9578,6 +9578,7 @@ LINUX KERNEL DUMP TEST MODULE (LKDTM) M: Kees Cook keescook@chromium.org S: Maintained F: drivers/misc/lkdtm/* +F: tools/testing/selftests/lkdtm/* LINUX KERNEL MEMORY CONSISTENCY MODEL (LKMM) M: Alan Stern stern@rowland.harvard.edu diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index b001c602414b..f0b02a12ba39 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -26,6 +26,7 @@ TARGETS += kexec TARGETS += kvm TARGETS += lib TARGETS += livepatch +TARGETS += lkdtm TARGETS += membarrier TARGETS += memfd TARGETS += memory-hotplug diff --git a/tools/testing/selftests/lkdtm/Makefile b/tools/testing/selftests/lkdtm/Makefile new file mode 100644 index 000000000000..1bcc9ee990eb --- /dev/null +++ b/tools/testing/selftests/lkdtm/Makefile @@ -0,0 +1,12 @@ +# SPDX-License-Identifier: GPL-2.0 +# Makefile for LKDTM regression tests

+include ../lib.mk

+# NOTE: $(OUTPUT) won't get default value if used before lib.mk +TEST_FILES := tests.txt +TEST_GEN_PROGS = $(patsubst %,$(OUTPUT)/%.sh,$(shell awk '{print $$1}' tests.txt | sed -e 's/#//')) +all: $(TEST_GEN_PROGS)

+$(OUTPUT)/%: run.sh tests.txt

• install -m 0744 run.sh $@

diff --git a/tools/testing/selftests/lkdtm/config b/tools/testing/selftests/lkdtm/config new file mode 100644 index 000000000000..d874990e442b --- /dev/null +++ b/tools/testing/selftests/lkdtm/config @@ -0,0 +1 @@ +CONFIG_LKDTM=y diff --git a/tools/testing/selftests/lkdtm/run.sh b/tools/testing/selftests/lkdtm/run.sh new file mode 100755 index 000000000000..793ee0d5d5a3 --- /dev/null +++ b/tools/testing/selftests/lkdtm/run.sh @@ -0,0 +1,91 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# +# This reads tests.txt for the list of LKDTM tests to invoke. Any marked +# with a leading "#" are skipped. The rest of the line after the +# test name is either the text to look for in dmesg for a "success", +# or the rationale for why a test is marked to be skipped. +# +set -e +TRIGGER=/sys/kernel/debug/provoke-crash/DIRECT

+# 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 4

Please add a define for this to indicate that this the kselftest skip code.

+fi

+# Figure out which test to run from our script name. +test=$(basename $0 .sh) +# Look up details about the test from master list of LKDTM tests. +line=$(egrep '^#?'"$test"'\b' tests.txt) +if [ -z "$line" ]; then

• echo "Skipped: missing test '$test' in tests.txt"
• exit 4

+fi +# Check that the test is known to LKDTM. +if ! egrep -q '^'"$test"'$' "$TRIGGER" ; then

• echo "Skipped: test '$test' missing in $TRIGGER!"
• exit 4

+fi

Same here

+# Extract notes/expected output from test list. +test=$(echo "$line" | cut -d" " -f1) +if echo "$line" | grep -q ' ' ; then

• expect=$(echo "$line" | cut -d" " -f2-)

+else

• expect=""

+fi

+# If the test is commented out, report a skip +if echo "$test" | grep -q '^#' ; then

• test=$(echo "$test" | cut -c2-)
• if [ -z "$expect" ]; then

• expect="crashes entire system"
  

• fi
• echo "Skipping $test: $expect"
• exit 4

Same here

+fi

+# If no expected output given, assume an Oops with back trace is success. +if [ -z "$expect" ]; then

• expect="call trace:"

+fi

+# Clear out dmesg for output reporting +dmesg -c >/dev/null

+# Prepare log for report checking +LOG=$(mktemp --tmpdir -t lkdtm-XXXXXX) +cleanup() {

• rm -f "$LOG"

+} +trap cleanup EXIT

+# Most shells yell about signals and we're expecting the "cat" process +# to usually be killed by the kernel. So we have to run it in a sub-shell +# and silence errors. +($SHELL -c 'cat <(echo '"$test"') >'"$TRIGGER" 2>/dev/null) || true

+# Record and dump the results +dmesg -c >"$LOG" +cat "$LOG" +# Check for expected output +if egrep -qi "$expect" "$LOG" ; then

• echo "$test: saw '$expect': ok"
• exit 0

+else

• if egrep -qi XFAIL: "$LOG" ; then

• echo "$test: saw 'XFAIL': [SKIP]"
  

• exit 4
  

• else

• echo "$test: missing '$expect': [FAIL]"
  

• exit 1
  

• fi

+fi diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt new file mode 100644 index 000000000000..fc55f8ef8bee --- /dev/null +++ b/tools/testing/selftests/lkdtm/tests.txt @@ -0,0 +1,70 @@ +#PANIC +BUG kernel BUG at +WARNING WARNING: +WARNING_MESSAGE message trigger +EXCEPTION +#LOOP Hangs the system +#EXHAUST_STACK Corrupts memory on failure +#CORRUPT_STACK Crashes entire system on success +#CORRUPT_STACK_STRONG Crashes entire system on success +CORRUPT_LIST_ADD list_add corruption +CORRUPT_LIST_DEL list_del corruption +CORRUPT_USER_DS Invalid address limit on user-mode return +STACK_GUARD_PAGE_LEADING +STACK_GUARD_PAGE_TRAILING +UNSET_SMEP CR4 bits went missing +UNALIGNED_LOAD_STORE_WRITE +#OVERWRITE_ALLOCATION Corrupts memory on failure +#WRITE_AFTER_FREE Corrupts memory on failure +READ_AFTER_FREE +#WRITE_BUDDY_AFTER_FREE Corrupts memory on failure +READ_BUDDY_AFTER_FREE +SLAB_FREE_DOUBLE +SLAB_FREE_CROSS +SLAB_FREE_PAGE +#SOFTLOCKUP Hangs the system +#HARDLOCKUP Hangs the system +#SPINLOCKUP Hangs the system +#HUNG_TASK Hangs the system +EXEC_DATA +EXEC_STACK +EXEC_KMALLOC +EXEC_VMALLOC +EXEC_RODATA +EXEC_USERSPACE +EXEC_NULL +ACCESS_USERSPACE +ACCESS_NULL +WRITE_RO +WRITE_RO_AFTER_INIT +WRITE_KERN +REFCOUNT_INC_OVERFLOW +REFCOUNT_ADD_OVERFLOW +REFCOUNT_INC_NOT_ZERO_OVERFLOW +REFCOUNT_ADD_NOT_ZERO_OVERFLOW +REFCOUNT_DEC_ZERO +REFCOUNT_DEC_NEGATIVE Negative detected: saturated +REFCOUNT_DEC_AND_TEST_NEGATIVE Negative detected: saturated +REFCOUNT_SUB_AND_TEST_NEGATIVE Negative detected: saturated +REFCOUNT_INC_ZERO +REFCOUNT_ADD_ZERO +REFCOUNT_INC_SATURATED Saturation detected: still saturated +REFCOUNT_DEC_SATURATED Saturation detected: still saturated +REFCOUNT_ADD_SATURATED Saturation detected: still saturated +REFCOUNT_INC_NOT_ZERO_SATURATED +REFCOUNT_ADD_NOT_ZERO_SATURATED +REFCOUNT_DEC_AND_TEST_SATURATED Saturation detected: still saturated +REFCOUNT_SUB_AND_TEST_SATURATED Saturation detected: still saturated +#REFCOUNT_TIMING timing only +#ATOMIC_TIMING timing only +USERCOPY_HEAP_SIZE_TO +USERCOPY_HEAP_SIZE_FROM +USERCOPY_HEAP_WHITELIST_TO +USERCOPY_HEAP_WHITELIST_FROM +USERCOPY_STACK_FRAME_TO +USERCOPY_STACK_FRAME_FROM +USERCOPY_STACK_BEYOND +USERCOPY_KERNEL +USERCOPY_KERNEL_DS +STACKLEAK_ERASING OK: the rest of the thread stack is properly erased +CFI_FORWARD_PROTO

Rest looks good. I can pull the v3 for 5.6-rc1

thanks, -- Shuah