selftests/ima: kexec_load syscall test

The kernel CONFIG_KEXEC_VERIFY_SIG option is limited to verifying a
kernel image's signature, when loaded via the kexec_file_load syscall.
There is no method for verifying a kernel image's signature loaded
via the kexec_load syscall.

This test verifies loading the kernel image via the kexec_load syscall
fails when the kernel CONFIG_KEXEC_VERIFY_SIG option is enabled on
systems with secureboot enabled[1].

[1] Detecting secureboot enabled is architecture specific.

Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index f1fe492c8e17d060d70009f5ff139cbf975c6f72..552c447af03d32b205b5cc2740e2252448bba081 100644 (file)
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -13,6 +13,7 @@ TARGETS += firmware
 TARGETS += ftrace
 TARGETS += futex
 TARGETS += gpio
+TARGETS += ima
 TARGETS += intel_pstate
 TARGETS += ipc
 TARGETS += kcmp

diff --git a/tools/testing/selftests/ima/Makefile b/tools/testing/selftests/ima/Makefile
new file mode 100644 (file)
index 0000000..0b3adf5
--- /dev/null
+++ b/tools/testing/selftests/ima/Makefile
@@ -0,0 +1,11 @@
+# Makefile for kexec_load
+
+uname_M := $(shell uname -m 2>/dev/null || echo not)
+ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/x86/ -e s/x86_64/x86/)
+
+ifeq ($(ARCH),x86)
+TEST_PROGS := test_kexec_load.sh
+
+include ../lib.mk
+
+endif

diff --git a/tools/testing/selftests/ima/config b/tools/testing/selftests/ima/config
new file mode 100644 (file)
index 0000000..6bc86d4
--- /dev/null
+++ b/tools/testing/selftests/ima/config
@@ -0,0 +1,4 @@
+CONFIG_IMA_APPRAISE
+CONFIG_IMA_ARCH_POLICY
+CONFIG_SECURITYFS
+CONFIG_KEXEC_VERIFY_SIG

diff --git a/tools/testing/selftests/ima/test_kexec_load.sh b/tools/testing/selftests/ima/test_kexec_load.sh
new file mode 100755 (executable)
index 0000000..1c10093
--- /dev/null
+++ b/tools/testing/selftests/ima/test_kexec_load.sh
@@ -0,0 +1,54 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+# Loading a kernel image via the kexec_load syscall should fail
+# when the kerne is CONFIG_KEXEC_VERIFY_SIG enabled and the system
+# is booted in secureboot mode.
+
+TEST="$0"
+EFIVARFS="/sys/firmware/efi/efivars"
+rc=0
+
+# Kselftest framework requirement - SKIP code is 4.
+ksft_skip=4
+
+# kexec requires root privileges
+if [ $UID != 0 ]; then
+       echo "$TEST: must be run as root" >&2
+       exit $ksft_skip
+fi
+
+# Make sure that efivars is mounted in the normal location
+if ! grep -q "^\S\+ $EFIVARFS efivarfs" /proc/mounts; then
+       echo "$TEST: efivars is not mounted on $EFIVARFS" >&2
+       exit $ksft_skip
+fi
+
+# Get secureboot mode
+file="$EFIVARFS/SecureBoot-*"
+if [ ! -e $file ]; then
+       echo "$TEST: unknown secureboot mode" >&2
+       exit $ksft_skip
+fi
+secureboot=`hexdump $file | awk '{print substr($4,length($4),1)}'`
+
+# kexec_load should fail in secure boot mode
+KERNEL_IMAGE="/boot/vmlinuz-`uname -r`"
+kexec -l $KERNEL_IMAGE &>> /dev/null
+if [ $? == 0 ]; then
+       kexec -u
+       if [ "$secureboot" == "1" ]; then
+               echo "$TEST: kexec_load succeeded [FAIL]"
+               rc=1
+       else
+               echo "$TEST: kexec_load succeeded [PASS]"
+       fi
+else
+       if [ "$secureboot" == "1" ]; then
+               echo "$TEST: kexec_load failed [PASS]"
+       else
+               echo "$TEST: kexec_load failed [FAIL]"
+               rc=1
+       fi
+fi
+
+exit $rc