Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1#!/usr/bin/env bash
2# SPDX-License-Identifier: GPL-2.0
3#
4# Test the "inc" interpreter.
5#
6# See include/uapi/linux/securebits.h, include/uapi/linux/fcntl.h and
7# samples/check-exec/inc.c
8#
9# Copyright © 2024 Microsoft Corporation
10
11set -u -e -o pipefail
12
13EXPECTED_OUTPUT="1"
14exec 2>/dev/null
15
16DIR="$(dirname $(readlink -f "$0"))"
17source "${DIR}"/../kselftest/ktap_helpers.sh
18
19exec_direct() {
20 local expect="$1"
21 local script="$2"
22 shift 2
23 local ret=0
24 local out
25
26 # Updates PATH for `env` to execute the `inc` interpreter.
27 out="$(PATH="." "$@" "${script}")" || ret=$?
28
29 if [[ ${ret} -ne ${expect} ]]; then
30 echo "ERROR: Wrong expectation for direct file execution: ${ret}"
31 return 1
32 fi
33 if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
34 echo "ERROR: Wrong output for direct file execution: ${out}"
35 return 1
36 fi
37}
38
39exec_indirect() {
40 local expect="$1"
41 local script="$2"
42 shift 2
43 local ret=0
44 local out
45
46 # Script passed as argument.
47 out="$("$@" ./inc "${script}")" || ret=$?
48
49 if [[ ${ret} -ne ${expect} ]]; then
50 echo "ERROR: Wrong expectation for indirect file execution: ${ret}"
51 return 1
52 fi
53 if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
54 echo "ERROR: Wrong output for indirect file execution: ${out}"
55 return 1
56 fi
57}
58
59exec_stdin_reg() {
60 local expect="$1"
61 local script="$2"
62 shift 2
63 local ret=0
64 local out
65
66 # Executing stdin must be allowed if the related file is executable.
67 out="$("$@" ./inc -i < "${script}")" || ret=$?
68
69 if [[ ${ret} -ne ${expect} ]]; then
70 echo "ERROR: Wrong expectation for stdin regular file execution: ${ret}"
71 return 1
72 fi
73 if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
74 echo "ERROR: Wrong output for stdin regular file execution: ${out}"
75 return 1
76 fi
77}
78
79exec_stdin_pipe() {
80 local expect="$1"
81 shift
82 local ret=0
83 local out
84
85 # A pipe is not executable.
86 out="$(cat script-exec.inc | "$@" ./inc -i)" || ret=$?
87
88 if [[ ${ret} -ne ${expect} ]]; then
89 echo "ERROR: Wrong expectation for stdin pipe execution: ${ret}"
90 return 1
91 fi
92}
93
94exec_argument() {
95 local expect="$1"
96 local ret=0
97 shift
98 local out
99
100 # Script not coming from a file must not be executed.
101 out="$("$@" ./inc -c "$(< script-exec.inc)")" || ret=$?
102
103 if [[ ${ret} -ne ${expect} ]]; then
104 echo "ERROR: Wrong expectation for arbitrary argument execution: ${ret}"
105 return 1
106 fi
107 if [[ ${ret} -eq 0 && "${out}" != "${EXPECTED_OUTPUT}" ]]; then
108 echo "ERROR: Wrong output for arbitrary argument execution: ${out}"
109 return 1
110 fi
111}
112
113exec_interactive() {
114 exec_stdin_pipe "$@"
115 exec_argument "$@"
116}
117
118ktap_test() {
119 ktap_test_result "$*" "$@"
120}
121
122ktap_print_header
123ktap_set_plan 28
124
125# Without secbit configuration, nothing is changed.
126
127ktap_print_msg "By default, executable scripts are allowed to be interpreted and executed."
128ktap_test exec_direct 0 script-exec.inc
129ktap_test exec_indirect 0 script-exec.inc
130
131ktap_print_msg "By default, executable stdin is allowed to be interpreted."
132ktap_test exec_stdin_reg 0 script-exec.inc
133
134ktap_print_msg "By default, non-executable scripts are allowed to be interpreted, but not directly executed."
135# We get 126 because of direct execution by Bash.
136ktap_test exec_direct 126 script-noexec.inc
137ktap_test exec_indirect 0 script-noexec.inc
138
139ktap_print_msg "By default, non-executable stdin is allowed to be interpreted."
140ktap_test exec_stdin_reg 0 script-noexec.inc
141
142ktap_print_msg "By default, interactive commands are allowed to be interpreted."
143ktap_test exec_interactive 0
144
145# With only file restriction: protect non-malicious users from inadvertent errors (e.g. python ~/Downloads/*.py).
146
147ktap_print_msg "With -f, executable scripts are allowed to be interpreted and executed."
148ktap_test exec_direct 0 script-exec.inc ./set-exec -f --
149ktap_test exec_indirect 0 script-exec.inc ./set-exec -f --
150
151ktap_print_msg "With -f, executable stdin is allowed to be interpreted."
152ktap_test exec_stdin_reg 0 script-exec.inc ./set-exec -f --
153
154ktap_print_msg "With -f, non-executable scripts are not allowed to be executed nor interpreted."
155# Direct execution of non-executable script is alwayse denied by the kernel.
156ktap_test exec_direct 1 script-noexec.inc ./set-exec -f --
157ktap_test exec_indirect 1 script-noexec.inc ./set-exec -f --
158
159ktap_print_msg "With -f, non-executable stdin is allowed to be interpreted."
160ktap_test exec_stdin_reg 0 script-noexec.inc ./set-exec -f --
161
162ktap_print_msg "With -f, interactive commands are allowed to be interpreted."
163ktap_test exec_interactive 0 ./set-exec -f --
164
165# With only denied interactive commands: check or monitor script content (e.g. with LSM).
166
167ktap_print_msg "With -i, executable scripts are allowed to be interpreted and executed."
168ktap_test exec_direct 0 script-exec.inc ./set-exec -i --
169ktap_test exec_indirect 0 script-exec.inc ./set-exec -i --
170
171ktap_print_msg "With -i, executable stdin is allowed to be interpreted."
172ktap_test exec_stdin_reg 0 script-exec.inc ./set-exec -i --
173
174ktap_print_msg "With -i, non-executable scripts are allowed to be interpreted, but not directly executed."
175# Direct execution of non-executable script is alwayse denied by the kernel.
176ktap_test exec_direct 1 script-noexec.inc ./set-exec -i --
177ktap_test exec_indirect 0 script-noexec.inc ./set-exec -i --
178
179ktap_print_msg "With -i, non-executable stdin is not allowed to be interpreted."
180ktap_test exec_stdin_reg 1 script-noexec.inc ./set-exec -i --
181
182ktap_print_msg "With -i, interactive commands are not allowed to be interpreted."
183ktap_test exec_interactive 1 ./set-exec -i --
184
185# With both file restriction and denied interactive commands: only allow executable scripts.
186
187ktap_print_msg "With -fi, executable scripts are allowed to be interpreted and executed."
188ktap_test exec_direct 0 script-exec.inc ./set-exec -fi --
189ktap_test exec_indirect 0 script-exec.inc ./set-exec -fi --
190
191ktap_print_msg "With -fi, executable stdin is allowed to be interpreted."
192ktap_test exec_stdin_reg 0 script-exec.inc ./set-exec -fi --
193
194ktap_print_msg "With -fi, non-executable scripts are not allowed to be interpreted nor executed."
195# Direct execution of non-executable script is alwayse denied by the kernel.
196ktap_test exec_direct 1 script-noexec.inc ./set-exec -fi --
197ktap_test exec_indirect 1 script-noexec.inc ./set-exec -fi --
198
199ktap_print_msg "With -fi, non-executable stdin is not allowed to be interpreted."
200ktap_test exec_stdin_reg 1 script-noexec.inc ./set-exec -fi --
201
202ktap_print_msg "With -fi, interactive commands are not allowed to be interpreted."
203ktap_test exec_interactive 1 ./set-exec -fi --
204
205ktap_finished