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