1 | // SPDX-License-Identifier: GPL-2.0 |
2 | |
3 | #ifdef __aarch64__ |
4 | #include <asm/hwcap.h> |
5 | #endif |
6 | |
7 | #include <linux/mman.h> |
8 | #include <linux/prctl.h> |
9 | |
10 | #include <stdio.h> |
11 | #include <stdlib.h> |
12 | #include <sys/auxv.h> |
13 | #include <sys/prctl.h> |
14 | #include <sys/wait.h> |
15 | #include <unistd.h> |
16 | |
17 | #include "../kselftest_harness.h" |
18 | |
19 | #ifndef __aarch64__ |
20 | # define PROT_BTI 0 |
21 | #endif |
22 | |
23 | TEST(prctl_flags) |
24 | { |
25 | EXPECT_LT(prctl(PR_SET_MDWE, PR_MDWE_NO_INHERIT, 0L, 0L, 7L), 0); |
26 | EXPECT_EQ(errno, EINVAL); |
27 | |
28 | EXPECT_LT(prctl(PR_SET_MDWE, 7L, 0L, 0L, 0L), 0); |
29 | EXPECT_EQ(errno, EINVAL); |
30 | EXPECT_LT(prctl(PR_SET_MDWE, 0L, 7L, 0L, 0L), 0); |
31 | EXPECT_EQ(errno, EINVAL); |
32 | EXPECT_LT(prctl(PR_SET_MDWE, 0L, 0L, 7L, 0L), 0); |
33 | EXPECT_EQ(errno, EINVAL); |
34 | EXPECT_LT(prctl(PR_SET_MDWE, 0L, 0L, 0L, 7L), 0); |
35 | EXPECT_EQ(errno, EINVAL); |
36 | |
37 | EXPECT_LT(prctl(PR_GET_MDWE, 7L, 0L, 0L, 0L), 0); |
38 | EXPECT_EQ(errno, EINVAL); |
39 | EXPECT_LT(prctl(PR_GET_MDWE, 0L, 7L, 0L, 0L), 0); |
40 | EXPECT_EQ(errno, EINVAL); |
41 | EXPECT_LT(prctl(PR_GET_MDWE, 0L, 0L, 7L, 0L), 0); |
42 | EXPECT_EQ(errno, EINVAL); |
43 | EXPECT_LT(prctl(PR_GET_MDWE, 0L, 0L, 0L, 7L), 0); |
44 | EXPECT_EQ(errno, EINVAL); |
45 | } |
46 | |
47 | FIXTURE(consecutive_prctl_flags) {}; |
48 | FIXTURE_SETUP(consecutive_prctl_flags) {} |
49 | FIXTURE_TEARDOWN(consecutive_prctl_flags) {} |
50 | |
51 | FIXTURE_VARIANT(consecutive_prctl_flags) |
52 | { |
53 | unsigned long first_flags; |
54 | unsigned long second_flags; |
55 | bool should_work; |
56 | }; |
57 | |
58 | FIXTURE_VARIANT_ADD(consecutive_prctl_flags, can_keep_no_flags) |
59 | { |
60 | .first_flags = 0, |
61 | .second_flags = 0, |
62 | .should_work = true, |
63 | }; |
64 | |
65 | FIXTURE_VARIANT_ADD(consecutive_prctl_flags, can_keep_exec_gain) |
66 | { |
67 | .first_flags = PR_MDWE_REFUSE_EXEC_GAIN, |
68 | .second_flags = PR_MDWE_REFUSE_EXEC_GAIN, |
69 | .should_work = true, |
70 | }; |
71 | |
72 | FIXTURE_VARIANT_ADD(consecutive_prctl_flags, can_keep_both_flags) |
73 | { |
74 | .first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT, |
75 | .second_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT, |
76 | .should_work = true, |
77 | }; |
78 | |
79 | FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_disable_mdwe) |
80 | { |
81 | .first_flags = PR_MDWE_REFUSE_EXEC_GAIN, |
82 | .second_flags = 0, |
83 | .should_work = false, |
84 | }; |
85 | |
86 | FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_disable_mdwe_no_inherit) |
87 | { |
88 | .first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT, |
89 | .second_flags = 0, |
90 | .should_work = false, |
91 | }; |
92 | |
93 | FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_disable_no_inherit) |
94 | { |
95 | .first_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT, |
96 | .second_flags = PR_MDWE_REFUSE_EXEC_GAIN, |
97 | .should_work = false, |
98 | }; |
99 | |
100 | FIXTURE_VARIANT_ADD(consecutive_prctl_flags, cant_enable_no_inherit) |
101 | { |
102 | .first_flags = PR_MDWE_REFUSE_EXEC_GAIN, |
103 | .second_flags = PR_MDWE_REFUSE_EXEC_GAIN | PR_MDWE_NO_INHERIT, |
104 | .should_work = false, |
105 | }; |
106 | |
107 | TEST_F(consecutive_prctl_flags, two_prctls) |
108 | { |
109 | int ret; |
110 | |
111 | EXPECT_EQ(prctl(PR_SET_MDWE, variant->first_flags, 0L, 0L, 0L), 0); |
112 | |
113 | ret = prctl(PR_SET_MDWE, variant->second_flags, 0L, 0L, 0L); |
114 | if (variant->should_work) { |
115 | EXPECT_EQ(ret, 0); |
116 | |
117 | ret = prctl(PR_GET_MDWE, 0L, 0L, 0L, 0L); |
118 | ASSERT_EQ(ret, variant->second_flags); |
119 | } else { |
120 | EXPECT_NE(ret, 0); |
121 | ASSERT_EQ(errno, EPERM); |
122 | } |
123 | } |
124 | |
125 | FIXTURE(mdwe) |
126 | { |
127 | void *p; |
128 | int flags; |
129 | size_t size; |
130 | pid_t pid; |
131 | }; |
132 | |
133 | FIXTURE_VARIANT(mdwe) |
134 | { |
135 | bool enabled; |
136 | bool forked; |
137 | bool inherit; |
138 | }; |
139 | |
140 | FIXTURE_VARIANT_ADD(mdwe, stock) |
141 | { |
142 | .enabled = false, |
143 | .forked = false, |
144 | .inherit = false, |
145 | }; |
146 | |
147 | FIXTURE_VARIANT_ADD(mdwe, enabled) |
148 | { |
149 | .enabled = true, |
150 | .forked = false, |
151 | .inherit = true, |
152 | }; |
153 | |
154 | FIXTURE_VARIANT_ADD(mdwe, inherited) |
155 | { |
156 | .enabled = true, |
157 | .forked = true, |
158 | .inherit = true, |
159 | }; |
160 | |
161 | FIXTURE_VARIANT_ADD(mdwe, not_inherited) |
162 | { |
163 | .enabled = true, |
164 | .forked = true, |
165 | .inherit = false, |
166 | }; |
167 | |
168 | static bool executable_map_should_fail(const FIXTURE_VARIANT(mdwe) *variant) |
169 | { |
170 | return variant->enabled && (!variant->forked || variant->inherit); |
171 | } |
172 | |
173 | FIXTURE_SETUP(mdwe) |
174 | { |
175 | unsigned long mdwe_flags; |
176 | int ret, status; |
177 | |
178 | self->p = NULL; |
179 | self->flags = MAP_SHARED | MAP_ANONYMOUS; |
180 | self->size = getpagesize(); |
181 | |
182 | if (!variant->enabled) |
183 | return; |
184 | |
185 | mdwe_flags = PR_MDWE_REFUSE_EXEC_GAIN; |
186 | if (!variant->inherit) |
187 | mdwe_flags |= PR_MDWE_NO_INHERIT; |
188 | |
189 | ret = prctl(PR_SET_MDWE, mdwe_flags, 0L, 0L, 0L); |
190 | ASSERT_EQ(ret, 0) { |
191 | TH_LOG("PR_SET_MDWE failed or unsupported" ); |
192 | } |
193 | |
194 | ret = prctl(PR_GET_MDWE, 0L, 0L, 0L, 0L); |
195 | ASSERT_EQ(ret, mdwe_flags); |
196 | |
197 | if (variant->forked) { |
198 | self->pid = fork(); |
199 | ASSERT_GE(self->pid, 0) { |
200 | TH_LOG("fork failed\n" ); |
201 | } |
202 | |
203 | if (self->pid > 0) { |
204 | ret = waitpid(self->pid, &status, 0); |
205 | ASSERT_TRUE(WIFEXITED(status)); |
206 | exit(WEXITSTATUS(status)); |
207 | } |
208 | } |
209 | } |
210 | |
211 | FIXTURE_TEARDOWN(mdwe) |
212 | { |
213 | if (self->p && self->p != MAP_FAILED) |
214 | munmap(self->p, self->size); |
215 | } |
216 | |
217 | TEST_F(mdwe, mmap_READ_EXEC) |
218 | { |
219 | self->p = mmap(NULL, self->size, PROT_READ | PROT_EXEC, self->flags, 0, 0); |
220 | EXPECT_NE(self->p, MAP_FAILED); |
221 | } |
222 | |
223 | TEST_F(mdwe, mmap_WRITE_EXEC) |
224 | { |
225 | self->p = mmap(NULL, self->size, PROT_WRITE | PROT_EXEC, self->flags, 0, 0); |
226 | if (executable_map_should_fail(variant)) { |
227 | EXPECT_EQ(self->p, MAP_FAILED); |
228 | } else { |
229 | EXPECT_NE(self->p, MAP_FAILED); |
230 | } |
231 | } |
232 | |
233 | TEST_F(mdwe, mprotect_stay_EXEC) |
234 | { |
235 | int ret; |
236 | |
237 | self->p = mmap(NULL, self->size, PROT_READ | PROT_EXEC, self->flags, 0, 0); |
238 | ASSERT_NE(self->p, MAP_FAILED); |
239 | |
240 | ret = mprotect(self->p, self->size, PROT_READ | PROT_EXEC); |
241 | EXPECT_EQ(ret, 0); |
242 | } |
243 | |
244 | TEST_F(mdwe, mprotect_add_EXEC) |
245 | { |
246 | int ret; |
247 | |
248 | self->p = mmap(NULL, self->size, PROT_READ, self->flags, 0, 0); |
249 | ASSERT_NE(self->p, MAP_FAILED); |
250 | |
251 | ret = mprotect(self->p, self->size, PROT_READ | PROT_EXEC); |
252 | if (executable_map_should_fail(variant)) { |
253 | EXPECT_LT(ret, 0); |
254 | } else { |
255 | EXPECT_EQ(ret, 0); |
256 | } |
257 | } |
258 | |
259 | TEST_F(mdwe, mprotect_WRITE_EXEC) |
260 | { |
261 | int ret; |
262 | |
263 | self->p = mmap(NULL, self->size, PROT_WRITE, self->flags, 0, 0); |
264 | ASSERT_NE(self->p, MAP_FAILED); |
265 | |
266 | ret = mprotect(self->p, self->size, PROT_WRITE | PROT_EXEC); |
267 | if (executable_map_should_fail(variant)) { |
268 | EXPECT_LT(ret, 0); |
269 | } else { |
270 | EXPECT_EQ(ret, 0); |
271 | } |
272 | } |
273 | |
274 | TEST_F(mdwe, mmap_FIXED) |
275 | { |
276 | void *p; |
277 | |
278 | self->p = mmap(NULL, self->size, PROT_READ, self->flags, 0, 0); |
279 | ASSERT_NE(self->p, MAP_FAILED); |
280 | |
281 | /* MAP_FIXED unmaps the existing page before mapping which is allowed */ |
282 | p = mmap(self->p, self->size, PROT_READ | PROT_EXEC, |
283 | self->flags | MAP_FIXED, 0, 0); |
284 | EXPECT_EQ(p, self->p); |
285 | } |
286 | |
287 | TEST_F(mdwe, arm64_BTI) |
288 | { |
289 | int ret; |
290 | |
291 | #ifdef __aarch64__ |
292 | if (!(getauxval(AT_HWCAP2) & HWCAP2_BTI)) |
293 | #endif |
294 | SKIP(return, "HWCAP2_BTI not supported" ); |
295 | |
296 | self->p = mmap(NULL, self->size, PROT_EXEC, self->flags, 0, 0); |
297 | ASSERT_NE(self->p, MAP_FAILED); |
298 | |
299 | ret = mprotect(self->p, self->size, PROT_EXEC | PROT_BTI); |
300 | EXPECT_EQ(ret, 0); |
301 | } |
302 | |
303 | TEST_HARNESS_MAIN |
304 | |