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#!/bin/bash
# SPDX-License-Identifier: GPL-2.0
set -e
set -u
set -o pipefail
IMA_POLICY_FILE="/sys/kernel/security/ima/policy"
TEST_BINARY="/bin/true"
VERBOSE="${SELFTESTS_VERBOSE:=0}"
LOG_FILE="$(mktemp /tmp/ima_setup.XXXX.log)"
usage()
{
echo "Usage: $0 <setup|cleanup|run|modify-bin|restore-bin|load-policy> <existing_tmp_dir>"
exit 1
}
ensure_mount_securityfs()
{
local securityfs_dir=$(grep "securityfs" /proc/mounts | awk '{print $2}')
if [ -z "${securityfs_dir}" ]; then
securityfs_dir=/sys/kernel/security
mount -t securityfs security "${securityfs_dir}"
fi
if [ ! -d "${securityfs_dir}" ]; then
echo "${securityfs_dir}: securityfs is not mounted" && exit 1
fi
}
setup()
{
local tmp_dir="$1"
local mount_img="${tmp_dir}/test.img"
local mount_dir="${tmp_dir}/mnt"
local copied_bin_path="${mount_dir}/$(basename ${TEST_BINARY})"
mkdir -p ${mount_dir}
dd if=/dev/zero of="${mount_img}" bs=1M count=10
losetup -f "${mount_img}"
local loop_device=$(losetup -a | grep ${mount_img:?} | cut -d ":" -f1)
mkfs.ext2 "${loop_device:?}"
mount "${loop_device}" "${mount_dir}"
cp "${TEST_BINARY}" "${mount_dir}"
local mount_uuid="$(blkid ${loop_device} | sed 's/.*UUID="\([^"]*\)".*/\1/')"
ensure_mount_securityfs
echo "measure func=BPRM_CHECK fsuuid=${mount_uuid}" > ${IMA_POLICY_FILE}
echo "measure func=BPRM_CHECK fsuuid=${mount_uuid}" > ${mount_dir}/policy_test
}
cleanup() {
local tmp_dir="$1"
local mount_img="${tmp_dir}/test.img"
local mount_dir="${tmp_dir}/mnt"
local loop_devices=$(losetup -a | grep ${mount_img:?} | cut -d ":" -f1)
for loop_dev in "${loop_devices}"; do
losetup -d $loop_dev
done
umount ${mount_dir}
rm -rf ${tmp_dir}
}
run()
{
local tmp_dir="$1"
local mount_dir="${tmp_dir}/mnt"
local copied_bin_path="${mount_dir}/$(basename ${TEST_BINARY})"
exec "${copied_bin_path}"
}
modify_bin()
{
local tmp_dir="$1"
local mount_dir="${tmp_dir}/mnt"
local copied_bin_path="${mount_dir}/$(basename ${TEST_BINARY})"
echo "mod" >> "${copied_bin_path}"
}
restore_bin()
{
local tmp_dir="$1"
local mount_dir="${tmp_dir}/mnt"
local copied_bin_path="${mount_dir}/$(basename ${TEST_BINARY})"
truncate -s -4 "${copied_bin_path}"
}
load_policy()
{
local tmp_dir="$1"
local mount_dir="${tmp_dir}/mnt"
echo ${mount_dir}/policy_test > ${IMA_POLICY_FILE} 2> /dev/null
}
catch()
{
local exit_code="$1"
local log_file="$2"
if [[ "${exit_code}" -ne 0 ]]; then
cat "${log_file}" >&3
fi
rm -f "${log_file}"
exit ${exit_code}
}
main()
{
[[ $# -ne 2 ]] && usage
local action="$1"
local tmp_dir="$2"
[[ ! -d "${tmp_dir}" ]] && echo "Directory ${tmp_dir} doesn't exist" && exit 1
if [[ "${action}" == "setup" ]]; then
setup "${tmp_dir}"
elif [[ "${action}" == "cleanup" ]]; then
cleanup "${tmp_dir}"
elif [[ "${action}" == "run" ]]; then
run "${tmp_dir}"
elif [[ "${action}" == "modify-bin" ]]; then
modify_bin "${tmp_dir}"
elif [[ "${action}" == "restore-bin" ]]; then
restore_bin "${tmp_dir}"
elif [[ "${action}" == "load-policy" ]]; then
load_policy "${tmp_dir}"
else
echo "Unknown action: ${action}"
exit 1
fi
}
trap 'catch "$?" "${LOG_FILE}"' EXIT
if [[ "${VERBOSE}" -eq 0 ]]; then
# Save the stderr to 3 so that we can output back to
# it incase of an error.
exec 3>&2 1>"${LOG_FILE}" 2>&1
fi
main "$@"
rm -f "${LOG_FILE}"
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