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#!/usr/bin/env bash
# SPDX-License-Identifier: GPL-2.0
#
# Test the "inc" interpreter.
#
# See include/uapi/linux/securebits.h, include/uapi/linux/fcntl.h and
# samples/check-exec/inc.c
#
# Copyright © 2024 Microsoft Corporation
set -u -e -o pipefail
EXPECTED_OUTPUT="1"
exec 2>/dev/null
DIR="$(dirname $(readlink -f "$0"))"
source "${DIR}"/../kselftest/ktap_helpers.sh
exec_direct() {
local expect="$1"
local script="$2"
shift 2
local ret=0
local out
# Updates PATH for `env` to execute the `inc` interpreter.
out="$(PATH="." "$@" "${script}")" || ret=$?
if [[ ${ret} -ne ${expect} ]]; then
echo "ERROR: Wrong expectation for direct file execution: ${ret}"
return 1
fi
if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
echo "ERROR: Wrong output for direct file execution: ${out}"
return 1
fi
}
exec_indirect() {
local expect="$1"
local script="$2"
shift 2
local ret=0
local out
# Script passed as argument.
out="$("$@" ./inc "${script}")" || ret=$?
if [[ ${ret} -ne ${expect} ]]; then
echo "ERROR: Wrong expectation for indirect file execution: ${ret}"
return 1
fi
if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
echo "ERROR: Wrong output for indirect file execution: ${out}"
return 1
fi
}
exec_stdin_reg() {
local expect="$1"
local script="$2"
shift 2
local ret=0
local out
# Executing stdin must be allowed if the related file is executable.
out="$("$@" ./inc -i < "${script}")" || ret=$?
if [[ ${ret} -ne ${expect} ]]; then
echo "ERROR: Wrong expectation for stdin regular file execution: ${ret}"
return 1
fi
if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
echo "ERROR: Wrong output for stdin regular file execution: ${out}"
return 1
fi
}
exec_stdin_pipe() {
local expect="$1"
shift
local ret=0
local out
# A pipe is not executable.
out="$(cat script-exec.inc | "$@" ./inc -i)" || ret=$?
if [[ ${ret} -ne ${expect} ]]; then
echo "ERROR: Wrong expectation for stdin pipe execution: ${ret}"
return 1
fi
}
exec_argument() {
local expect="$1"
local ret=0
shift
local out
# Script not coming from a file must not be executed.
out="$("$@" ./inc -c "$(< script-exec.inc)")" || ret=$?
if [[ ${ret} -ne ${expect} ]]; then
echo "ERROR: Wrong expectation for arbitrary argument execution: ${ret}"
return 1
fi
if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
echo "ERROR: Wrong output for arbitrary argument execution: ${out}"
return 1
fi
}
exec_interactive() {
exec_stdin_pipe "$@"
exec_argument "$@"
}
ktap_test() {
ktap_test_result "$*" "$@"
}
ktap_print_header
ktap_set_plan 28
# Without secbit configuration, nothing is changed.
ktap_print_msg "By default, executable scripts are allowed to be interpreted and executed."
ktap_test exec_direct 0 script-exec.inc
ktap_test exec_indirect 0 script-exec.inc
ktap_print_msg "By default, executable stdin is allowed to be interpreted."
ktap_test exec_stdin_reg 0 script-exec.inc
ktap_print_msg "By default, non-executable scripts are allowed to be interpreted, but not directly executed."
# We get 126 because of direct execution by Bash.
ktap_test exec_direct 126 script-noexec.inc
ktap_test exec_indirect 0 script-noexec.inc
ktap_print_msg "By default, non-executable stdin is allowed to be interpreted."
ktap_test exec_stdin_reg 0 script-noexec.inc
ktap_print_msg "By default, interactive commands are allowed to be interpreted."
ktap_test exec_interactive 0
# With only file restriction: protect non-malicious users from inadvertent errors (e.g. python ~/Downloads/*.py).
ktap_print_msg "With -f, executable scripts are allowed to be interpreted and executed."
ktap_test exec_direct 0 script-exec.inc ./set-exec -f --
ktap_test exec_indirect 0 script-exec.inc ./set-exec -f --
ktap_print_msg "With -f, executable stdin is allowed to be interpreted."
ktap_test exec_stdin_reg 0 script-exec.inc ./set-exec -f --
ktap_print_msg "With -f, non-executable scripts are not allowed to be executed nor interpreted."
# Direct execution of non-executable script is alwayse denied by the kernel.
ktap_test exec_direct 1 script-noexec.inc ./set-exec -f --
ktap_test exec_indirect 1 script-noexec.inc ./set-exec -f --
ktap_print_msg "With -f, non-executable stdin is allowed to be interpreted."
ktap_test exec_stdin_reg 0 script-noexec.inc ./set-exec -f --
ktap_print_msg "With -f, interactive commands are allowed to be interpreted."
ktap_test exec_interactive 0 ./set-exec -f --
# With only denied interactive commands: check or monitor script content (e.g. with LSM).
ktap_print_msg "With -i, executable scripts are allowed to be interpreted and executed."
ktap_test exec_direct 0 script-exec.inc ./set-exec -i --
ktap_test exec_indirect 0 script-exec.inc ./set-exec -i --
ktap_print_msg "With -i, executable stdin is allowed to be interpreted."
ktap_test exec_stdin_reg 0 script-exec.inc ./set-exec -i --
ktap_print_msg "With -i, non-executable scripts are allowed to be interpreted, but not directly executed."
# Direct execution of non-executable script is alwayse denied by the kernel.
ktap_test exec_direct 1 script-noexec.inc ./set-exec -i --
ktap_test exec_indirect 0 script-noexec.inc ./set-exec -i --
ktap_print_msg "With -i, non-executable stdin is not allowed to be interpreted."
ktap_test exec_stdin_reg 1 script-noexec.inc ./set-exec -i --
ktap_print_msg "With -i, interactive commands are not allowed to be interpreted."
ktap_test exec_interactive 1 ./set-exec -i --
# With both file restriction and denied interactive commands: only allow executable scripts.
ktap_print_msg "With -fi, executable scripts are allowed to be interpreted and executed."
ktap_test exec_direct 0 script-exec.inc ./set-exec -fi --
ktap_test exec_indirect 0 script-exec.inc ./set-exec -fi --
ktap_print_msg "With -fi, executable stdin is allowed to be interpreted."
ktap_test exec_stdin_reg 0 script-exec.inc ./set-exec -fi --
ktap_print_msg "With -fi, non-executable scripts are not allowed to be interpreted nor executed."
# Direct execution of non-executable script is alwayse denied by the kernel.
ktap_test exec_direct 1 script-noexec.inc ./set-exec -fi --
ktap_test exec_indirect 1 script-noexec.inc ./set-exec -fi --
ktap_print_msg "With -fi, non-executable stdin is not allowed to be interpreted."
ktap_test exec_stdin_reg 1 script-noexec.inc ./set-exec -fi --
ktap_print_msg "With -fi, interactive commands are not allowed to be interpreted."
ktap_test exec_interactive 1 ./set-exec -fi --
ktap_finished
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