1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Landlock test helpers
4 *
5 * Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
6 * Copyright © 2019-2020 ANSSI
7 * Copyright © 2021 Microsoft Corporation
8 */
9
10 #include <errno.h>
11 #include <linux/landlock.h>
12 #include <sys/capability.h>
13 #include <sys/syscall.h>
14 #include <sys/types.h>
15 #include <sys/wait.h>
16 #include <unistd.h>
17
18 #include "../kselftest_harness.h"
19
20 #ifndef ARRAY_SIZE
21 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
22 #endif
23
24 /*
25 * TEST_F_FORK() is useful when a test drop privileges but the corresponding
26 * FIXTURE_TEARDOWN() requires them (e.g. to remove files from a directory
27 * where write actions are denied). For convenience, FIXTURE_TEARDOWN() is
28 * also called when the test failed, but not when FIXTURE_SETUP() failed. For
29 * this to be possible, we must not call abort() but instead exit smoothly
30 * (hence the step print).
31 */
32 /* clang-format off */
33 #define TEST_F_FORK(fixture_name, test_name) \
34 static void fixture_name##_##test_name##_child( \
35 struct __test_metadata *_metadata, \
36 FIXTURE_DATA(fixture_name) *self, \
37 const FIXTURE_VARIANT(fixture_name) *variant); \
38 TEST_F(fixture_name, test_name) \
39 { \
40 int status; \
41 const pid_t child = fork(); \
42 if (child < 0) \
43 abort(); \
44 if (child == 0) { \
45 _metadata->no_print = 1; \
46 fixture_name##_##test_name##_child(_metadata, self, variant); \
47 if (_metadata->skip) \
48 _exit(255); \
49 if (_metadata->passed) \
50 _exit(0); \
51 _exit(_metadata->step); \
52 } \
53 if (child != waitpid(child, &status, 0)) \
54 abort(); \
55 if (WIFSIGNALED(status) || !WIFEXITED(status)) { \
56 _metadata->passed = 0; \
57 _metadata->step = 1; \
58 return; \
59 } \
60 switch (WEXITSTATUS(status)) { \
61 case 0: \
62 _metadata->passed = 1; \
63 break; \
64 case 255: \
65 _metadata->passed = 1; \
66 _metadata->skip = 1; \
67 break; \
68 default: \
69 _metadata->passed = 0; \
70 _metadata->step = WEXITSTATUS(status); \
71 break; \
72 } \
73 } \
74 static void fixture_name##_##test_name##_child( \
75 struct __test_metadata __attribute__((unused)) *_metadata, \
76 FIXTURE_DATA(fixture_name) __attribute__((unused)) *self, \
77 const FIXTURE_VARIANT(fixture_name) \
78 __attribute__((unused)) *variant)
79 /* clang-format on */
80
81 #ifndef landlock_create_ruleset
82 static inline int
landlock_create_ruleset(const struct landlock_ruleset_attr * const attr,const size_t size,const __u32 flags)83 landlock_create_ruleset(const struct landlock_ruleset_attr *const attr,
84 const size_t size, const __u32 flags)
85 {
86 return syscall(__NR_landlock_create_ruleset, attr, size, flags);
87 }
88 #endif
89
90 #ifndef landlock_add_rule
landlock_add_rule(const int ruleset_fd,const enum landlock_rule_type rule_type,const void * const rule_attr,const __u32 flags)91 static inline int landlock_add_rule(const int ruleset_fd,
92 const enum landlock_rule_type rule_type,
93 const void *const rule_attr,
94 const __u32 flags)
95 {
96 return syscall(__NR_landlock_add_rule, ruleset_fd, rule_type, rule_attr,
97 flags);
98 }
99 #endif
100
101 #ifndef landlock_restrict_self
landlock_restrict_self(const int ruleset_fd,const __u32 flags)102 static inline int landlock_restrict_self(const int ruleset_fd,
103 const __u32 flags)
104 {
105 return syscall(__NR_landlock_restrict_self, ruleset_fd, flags);
106 }
107 #endif
108
_init_caps(struct __test_metadata * const _metadata,bool drop_all)109 static void _init_caps(struct __test_metadata *const _metadata, bool drop_all)
110 {
111 cap_t cap_p;
112 /* Only these three capabilities are useful for the tests. */
113 const cap_value_t caps[] = {
114 CAP_DAC_OVERRIDE,
115 CAP_MKNOD,
116 CAP_SYS_ADMIN,
117 CAP_SYS_CHROOT,
118 };
119
120 cap_p = cap_get_proc();
121 EXPECT_NE(NULL, cap_p)
122 {
123 TH_LOG("Failed to cap_get_proc: %s", strerror(errno));
124 }
125 EXPECT_NE(-1, cap_clear(cap_p))
126 {
127 TH_LOG("Failed to cap_clear: %s", strerror(errno));
128 }
129 if (!drop_all) {
130 EXPECT_NE(-1, cap_set_flag(cap_p, CAP_PERMITTED,
131 ARRAY_SIZE(caps), caps, CAP_SET))
132 {
133 TH_LOG("Failed to cap_set_flag: %s", strerror(errno));
134 }
135 }
136 EXPECT_NE(-1, cap_set_proc(cap_p))
137 {
138 TH_LOG("Failed to cap_set_proc: %s", strerror(errno));
139 }
140 EXPECT_NE(-1, cap_free(cap_p))
141 {
142 TH_LOG("Failed to cap_free: %s", strerror(errno));
143 }
144 }
145
146 /* We cannot put such helpers in a library because of kselftest_harness.h . */
147 __attribute__((__unused__)) static void
disable_caps(struct __test_metadata * const _metadata)148 disable_caps(struct __test_metadata *const _metadata)
149 {
150 _init_caps(_metadata, false);
151 }
152
153 __attribute__((__unused__)) static void
drop_caps(struct __test_metadata * const _metadata)154 drop_caps(struct __test_metadata *const _metadata)
155 {
156 _init_caps(_metadata, true);
157 }
158
_effective_cap(struct __test_metadata * const _metadata,const cap_value_t caps,const cap_flag_value_t value)159 static void _effective_cap(struct __test_metadata *const _metadata,
160 const cap_value_t caps, const cap_flag_value_t value)
161 {
162 cap_t cap_p;
163
164 cap_p = cap_get_proc();
165 EXPECT_NE(NULL, cap_p)
166 {
167 TH_LOG("Failed to cap_get_proc: %s", strerror(errno));
168 }
169 EXPECT_NE(-1, cap_set_flag(cap_p, CAP_EFFECTIVE, 1, &caps, value))
170 {
171 TH_LOG("Failed to cap_set_flag: %s", strerror(errno));
172 }
173 EXPECT_NE(-1, cap_set_proc(cap_p))
174 {
175 TH_LOG("Failed to cap_set_proc: %s", strerror(errno));
176 }
177 EXPECT_NE(-1, cap_free(cap_p))
178 {
179 TH_LOG("Failed to cap_free: %s", strerror(errno));
180 }
181 }
182
183 __attribute__((__unused__)) static void
set_cap(struct __test_metadata * const _metadata,const cap_value_t caps)184 set_cap(struct __test_metadata *const _metadata, const cap_value_t caps)
185 {
186 _effective_cap(_metadata, caps, CAP_SET);
187 }
188
189 __attribute__((__unused__)) static void
clear_cap(struct __test_metadata * const _metadata,const cap_value_t caps)190 clear_cap(struct __test_metadata *const _metadata, const cap_value_t caps)
191 {
192 _effective_cap(_metadata, caps, CAP_CLEAR);
193 }
194