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Subject[PATCH v2] selftests/lkdtm: Add tests for LKDTM targets
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 $TRIGGER (need to run as root?)"
+ fi
+ # Skip this test
+ exit 4
+fi
+
+# Figure out which test to run from our script name.
+test=$(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 $TRIGGER!"
+ exit 4
+fi
+
+# Extract notes/expected output from test list.
+test=$(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: $expect"
+ exit 4
+fi
+
+# If no expected output given, assume an Oops with back trace is success.
+if [ -z "$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
--
2.20.1

--
Kees Cook

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