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