xref: /linux/tools/testing/selftests/bpf/ima_setup.sh (revision 69bfec7548f4c1595bac0e3ddfc0458a5af31f4c) 
1#!/bin/bash
2# SPDX-License-Identifier: GPL-2.0
3
4set -e
5set -u
6set -o pipefail
7
8IMA_POLICY_FILE="/sys/kernel/security/ima/policy"
9TEST_BINARY="/bin/true"
10VERBOSE="${SELFTESTS_VERBOSE:=0}"
11LOG_FILE="$(mktemp /tmp/ima_setup.XXXX.log)"
12
13usage()
14{
15	echo "Usage: $0 <setup|cleanup|run|modify-bin|restore-bin|load-policy> <existing_tmp_dir>"
16	exit 1
17}
18
19ensure_mount_securityfs()
20{
21	local securityfs_dir=$(grep "securityfs" /proc/mounts | awk '{print $2}')
22
23	if [ -z "${securityfs_dir}" ]; then
24		securityfs_dir=/sys/kernel/security
25		mount -t securityfs security "${securityfs_dir}"
26	fi
27
28	if [ ! -d "${securityfs_dir}" ]; then
29		echo "${securityfs_dir}: securityfs is not mounted" && exit 1
30	fi
31}
32
33setup()
34{
35	local tmp_dir="$1"
36	local mount_img="${tmp_dir}/test.img"
37	local mount_dir="${tmp_dir}/mnt"
38	local copied_bin_path="${mount_dir}/$(basename ${TEST_BINARY})"
39	mkdir -p ${mount_dir}
40
41	dd if=/dev/zero of="${mount_img}" bs=1M count=10
42
43	losetup -f "${mount_img}"
44	local loop_device=$(losetup -a | grep ${mount_img:?} | cut -d ":" -f1)
45
46	mkfs.ext2 "${loop_device:?}"
47	mount "${loop_device}" "${mount_dir}"
48
49	cp "${TEST_BINARY}" "${mount_dir}"
50	local mount_uuid="$(blkid ${loop_device} | sed 's/.*UUID="\([^"]*\)".*/\1/')"
51
52	ensure_mount_securityfs
53	echo "measure func=BPRM_CHECK fsuuid=${mount_uuid}" > ${IMA_POLICY_FILE}
54	echo "measure func=BPRM_CHECK fsuuid=${mount_uuid}" > ${mount_dir}/policy_test
55}
56
57cleanup() {
58	local tmp_dir="$1"
59	local mount_img="${tmp_dir}/test.img"
60	local mount_dir="${tmp_dir}/mnt"
61
62	local loop_devices=$(losetup -a | grep ${mount_img:?} | cut -d ":" -f1)
63
64	for loop_dev in "${loop_devices}"; do
65		losetup -d $loop_dev
66	done
67
68	umount ${mount_dir}
69	rm -rf ${tmp_dir}
70}
71
72run()
73{
74	local tmp_dir="$1"
75	local mount_dir="${tmp_dir}/mnt"
76	local copied_bin_path="${mount_dir}/$(basename ${TEST_BINARY})"
77
78	exec "${copied_bin_path}"
79}
80
81modify_bin()
82{
83	local tmp_dir="$1"
84	local mount_dir="${tmp_dir}/mnt"
85	local copied_bin_path="${mount_dir}/$(basename ${TEST_BINARY})"
86
87	echo "mod" >> "${copied_bin_path}"
88}
89
90restore_bin()
91{
92	local tmp_dir="$1"
93	local mount_dir="${tmp_dir}/mnt"
94	local copied_bin_path="${mount_dir}/$(basename ${TEST_BINARY})"
95
96	truncate -s -4 "${copied_bin_path}"
97}
98
99load_policy()
100{
101	local tmp_dir="$1"
102	local mount_dir="${tmp_dir}/mnt"
103
104	echo ${mount_dir}/policy_test > ${IMA_POLICY_FILE} 2> /dev/null
105}
106
107catch()
108{
109	local exit_code="$1"
110	local log_file="$2"
111
112	if [[ "${exit_code}" -ne 0 ]]; then
113		cat "${log_file}" >&3
114	fi
115
116	rm -f "${log_file}"
117	exit ${exit_code}
118}
119
120main()
121{
122	[[ $# -ne 2 ]] && usage
123
124	local action="$1"
125	local tmp_dir="$2"
126
127	[[ ! -d "${tmp_dir}" ]] && echo "Directory ${tmp_dir} doesn't exist" && exit 1
128
129	if [[ "${action}" == "setup" ]]; then
130		setup "${tmp_dir}"
131	elif [[ "${action}" == "cleanup" ]]; then
132		cleanup "${tmp_dir}"
133	elif [[ "${action}" == "run" ]]; then
134		run "${tmp_dir}"
135	elif [[ "${action}" == "modify-bin" ]]; then
136		modify_bin "${tmp_dir}"
137	elif [[ "${action}" == "restore-bin" ]]; then
138		restore_bin "${tmp_dir}"
139	elif [[ "${action}" == "load-policy" ]]; then
140		load_policy "${tmp_dir}"
141	else
142		echo "Unknown action: ${action}"
143		exit 1
144	fi
145}
146
147trap 'catch "$?" "${LOG_FILE}"' EXIT
148
149if [[ "${VERBOSE}" -eq 0 ]]; then
150	# Save the stderr to 3 so that we can output back to
151	# it incase of an error.
152	exec 3>&2 1>"${LOG_FILE}" 2>&1
153fi
154
155main "$@"
156rm -f "${LOG_FILE}"
157