1 677d90f7 2021-03-12 op /*
  2 677d90f7 2021-03-12 op  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
  3 677d90f7 2021-03-12 op  *
  4 677d90f7 2021-03-12 op  * Permission to use, copy, modify, and distribute this software for any
  5 677d90f7 2021-03-12 op  * purpose with or without fee is hereby granted, provided that the above
  6 677d90f7 2021-03-12 op  * copyright notice and this permission notice appear in all copies.
  7 677d90f7 2021-03-12 op  *
  8 677d90f7 2021-03-12 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  9 677d90f7 2021-03-12 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 10 677d90f7 2021-03-12 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 11 677d90f7 2021-03-12 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 12 677d90f7 2021-03-12 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 13 677d90f7 2021-03-12 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 14 677d90f7 2021-03-12 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 15 677d90f7 2021-03-12 op  */
 16 677d90f7 2021-03-12 op 
 17 a9d11f81 2021-10-08 op #include "compat.h"
 18 a9d11f81 2021-10-08 op 
 19 4b877649 2021-10-07 op #include "fs.h"
 20 754622a2 2021-03-15 op #include "telescope.h"
 21 677d90f7 2021-03-12 op 
 22 677d90f7 2021-03-12 op #ifdef __OpenBSD__
 23 677d90f7 2021-03-12 op 
 24 fced318d 2021-10-08 op # include <errno.h>
 25 35e1f40a 2021-03-14 op # include <limits.h>
 26 35e1f40a 2021-03-14 op # include <stdlib.h>
 27 35e1f40a 2021-03-14 op # include <string.h>
 28 2b1f38ab 2021-03-13 op # include <unistd.h>
 29 2b1f38ab 2021-03-13 op 
 30 677d90f7 2021-03-12 op void
 31 17c10c65 2021-07-12 op sandbox_net_process(void)
 32 677d90f7 2021-03-12 op {
 33 677d90f7 2021-03-12 op 	if (pledge("stdio inet dns", NULL) == -1)
 34 677d90f7 2021-03-12 op 		err(1, "pledge");
 35 677d90f7 2021-03-12 op }
 36 677d90f7 2021-03-12 op 
 37 b1d4d01b 2021-03-14 op void
 38 b1d4d01b 2021-03-14 op sandbox_ui_process(void)
 39 b1d4d01b 2021-03-14 op {
 40 4cf6ba13 2022-02-11 op 	if (pledge("stdio tty unix recvfd", NULL) == -1)
 41 b1d4d01b 2021-03-14 op 		err(1, "pledge");
 42 b1d4d01b 2021-03-14 op }
 43 b1d4d01b 2021-03-14 op 
 44 35e1f40a 2021-03-14 op void
 45 35e1f40a 2021-03-14 op sandbox_fs_process(void)
 46 35e1f40a 2021-03-14 op {
 47 35e1f40a 2021-03-14 op 	char path[PATH_MAX];
 48 35e1f40a 2021-03-14 op 
 49 de2a69bb 2021-05-17 op 	if (unveil("/tmp", "rwc") == -1)
 50 e9cb759e 2021-10-08 op 		err(1, "unveil(/tmp)");
 51 35e1f40a 2021-03-14 op 
 52 35e1f40a 2021-03-14 op 	strlcpy(path, getenv("HOME"), sizeof(path));
 53 35e1f40a 2021-03-14 op 	strlcat(path, "/Downloads", sizeof(path));
 54 4380c692 2021-10-08 op 	if (unveil(path, "rwc") == -1 && errno != ENOENT)
 55 fd0beb53 2021-10-07 op 		err(1, "unveil(%s)", path);
 56 35e1f40a 2021-03-14 op 
 57 4b877649 2021-10-07 op 	if (unveil(config_path_base, "rwc") == -1)
 58 fd0beb53 2021-10-07 op 		err(1, "unveil(%s)", config_path_base);
 59 35e1f40a 2021-03-14 op 
 60 4b877649 2021-10-07 op 	if (unveil(data_path_base, "rwc") == -1)
 61 fd0beb53 2021-10-07 op 		err(1, "unveil(%s)", data_path_base);
 62 4b877649 2021-10-07 op 
 63 4b877649 2021-10-07 op 	if (unveil(cache_path_base, "rwc") == -1)
 64 fd0beb53 2021-10-07 op 		err(1, "unveil(%s)", cache_path_base);
 65 4b877649 2021-10-07 op 
 66 de2a69bb 2021-05-17 op 	if (pledge("stdio rpath wpath cpath sendfd", NULL) == -1)
 67 35e1f40a 2021-03-14 op 		err(1, "pledge");
 68 35e1f40a 2021-03-14 op }
 69 35e1f40a 2021-03-14 op 
 70 a9d11f81 2021-10-08 op #elif HAVE_LINUX_LANDLOCK_H
 71 a9d11f81 2021-10-08 op 
 72 a9d11f81 2021-10-08 op #include <linux/landlock.h>
 73 a9d11f81 2021-10-08 op #include <linux/prctl.h>
 74 a9d11f81 2021-10-08 op 
 75 a9d11f81 2021-10-08 op #include <sys/prctl.h>
 76 a9d11f81 2021-10-08 op #include <sys/stat.h>
 77 a9d11f81 2021-10-08 op #include <sys/syscall.h>
 78 a9d11f81 2021-10-08 op 
 79 fced318d 2021-10-08 op #include <errno.h>
 80 a9d11f81 2021-10-08 op #include <fcntl.h>
 81 a9d11f81 2021-10-08 op #include <stdlib.h>
 82 a9d11f81 2021-10-08 op #include <string.h>
 83 a9d11f81 2021-10-08 op #include <unistd.h>
 84 a9d11f81 2021-10-08 op 
 85 a9d11f81 2021-10-08 op /*
 86 a9d11f81 2021-10-08 op  * What's the deal with landlock?  While distro with linux >= 5.13
 87 a9d11f81 2021-10-08 op  * have the struct declarations, libc wrappers are missing.  The
 88 a9d11f81 2021-10-08 op  * sample landlock code provided by the authors includes these "shims"
 89 a9d11f81 2021-10-08 op  * in their example for the landlock API until libc provides them.
 90 a9d11f81 2021-10-08 op  *
 91 a9d11f81 2021-10-08 op  * Linux is such a mess sometimes.  /rant
 92 a9d11f81 2021-10-08 op  */
 93 a9d11f81 2021-10-08 op 
 94 a9d11f81 2021-10-08 op #ifndef landlock_create_ruleset
 95 a9d11f81 2021-10-08 op static inline int
 96 a9d11f81 2021-10-08 op landlock_create_ruleset(const struct landlock_ruleset_attr *attr, size_t size,
 97 a9d11f81 2021-10-08 op     __u32 flags)
 98 a9d11f81 2021-10-08 op {
 99 a9d11f81 2021-10-08 op 	return syscall(__NR_landlock_create_ruleset, attr, size, flags);
100 a9d11f81 2021-10-08 op }
101 a9d11f81 2021-10-08 op #endif
102 a9d11f81 2021-10-08 op 
103 a9d11f81 2021-10-08 op #ifndef landlock_add_rule
104 a9d11f81 2021-10-08 op static inline int
105 a9d11f81 2021-10-08 op landlock_add_rule(int ruleset_fd, enum landlock_rule_type type,
106 a9d11f81 2021-10-08 op     const void *attr, __u32 flags)
107 a9d11f81 2021-10-08 op {
108 a9d11f81 2021-10-08 op 	return syscall(__NR_landlock_add_rule, ruleset_fd, type, attr, flags);
109 a9d11f81 2021-10-08 op }
110 a9d11f81 2021-10-08 op #endif
111 a9d11f81 2021-10-08 op 
112 a9d11f81 2021-10-08 op #ifndef landlock_restrict_self
113 a9d11f81 2021-10-08 op static inline int
114 a9d11f81 2021-10-08 op landlock_restrict_self(int ruleset_fd, __u32 flags)
115 a9d11f81 2021-10-08 op {
116 a9d11f81 2021-10-08 op 	return syscall(__NR_landlock_restrict_self, ruleset_fd, flags);
117 a9d11f81 2021-10-08 op }
118 a9d11f81 2021-10-08 op #endif
119 a9d11f81 2021-10-08 op 
120 a9d11f81 2021-10-08 op static int
121 a9d11f81 2021-10-08 op open_landlock(void)
122 a9d11f81 2021-10-08 op {
123 4ab3b651 2021-11-29 op 	int fd;
124 a9d11f81 2021-10-08 op 	struct landlock_ruleset_attr attr = {
125 35ae81fd 2022-02-10 op 		.handled_access_fs =	LANDLOCK_ACCESS_FS_EXECUTE |
126 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_READ_FILE |
127 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_READ_DIR |
128 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_WRITE_FILE |
129 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_REMOVE_DIR |
130 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_REMOVE_FILE |
131 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_CHAR |
132 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_DIR |
133 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_REG |
134 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_SOCK |
135 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_FIFO |
136 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_BLOCK |
137 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_SYM,
138 a9d11f81 2021-10-08 op 	};
139 a9d11f81 2021-10-08 op 
140 4ab3b651 2021-11-29 op 	fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
141 4ab3b651 2021-11-29 op 	if (fd == -1) {
142 4ab3b651 2021-11-29 op 		switch (errno) {
143 4ab3b651 2021-11-29 op 		case ENOSYS:
144 4ab3b651 2021-11-29 op 		case EOPNOTSUPP:
145 4ab3b651 2021-11-29 op 			return -1;
146 4ab3b651 2021-11-29 op 		default:
147 4ab3b651 2021-11-29 op 			err(1, "can't create landlock ruleset");
148 4ab3b651 2021-11-29 op 		}
149 4ab3b651 2021-11-29 op 	}
150 4ab3b651 2021-11-29 op 	return fd;
151 a9d11f81 2021-10-08 op }
152 a9d11f81 2021-10-08 op 
153 a9d11f81 2021-10-08 op static int
154 a9d11f81 2021-10-08 op landlock_unveil(int landlock_fd, const char *path, int perms)
155 a9d11f81 2021-10-08 op {
156 a9d11f81 2021-10-08 op 	struct landlock_path_beneath_attr pb;
157 a9d11f81 2021-10-08 op 	int err, saved_errno;
158 a9d11f81 2021-10-08 op 
159 a9d11f81 2021-10-08 op 	pb.allowed_access = perms;
160 a9d11f81 2021-10-08 op 
161 a9d11f81 2021-10-08 op 	if ((pb.parent_fd = open(path, O_PATH)) == -1)
162 a9d11f81 2021-10-08 op 		return -1;
163 a9d11f81 2021-10-08 op 
164 a9d11f81 2021-10-08 op 	err = landlock_add_rule(landlock_fd, LANDLOCK_RULE_PATH_BENEATH,
165 a9d11f81 2021-10-08 op 	    &pb, 0);
166 a9d11f81 2021-10-08 op 	saved_errno = errno;
167 a9d11f81 2021-10-08 op 	close(pb.parent_fd);
168 a9d11f81 2021-10-08 op 	errno = saved_errno;
169 a9d11f81 2021-10-08 op 	return err ? -1 : 0;
170 a9d11f81 2021-10-08 op }
171 a9d11f81 2021-10-08 op 
172 a9d11f81 2021-10-08 op static int
173 a9d11f81 2021-10-08 op landlock_apply(int fd)
174 a9d11f81 2021-10-08 op {
175 a9d11f81 2021-10-08 op 	int r, saved_errno;
176 a9d11f81 2021-10-08 op 
177 a9d11f81 2021-10-08 op 	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1)
178 a9d11f81 2021-10-08 op 		err(1, "%s: prctl(PR_SET_NO_NEW_PRIVS)", __func__);
179 a9d11f81 2021-10-08 op 
180 a9d11f81 2021-10-08 op 	r = landlock_restrict_self(fd, 0);
181 a9d11f81 2021-10-08 op 	saved_errno = errno;
182 a9d11f81 2021-10-08 op 	close(fd);
183 a9d11f81 2021-10-08 op 	errno = saved_errno;
184 a9d11f81 2021-10-08 op 	return r ? -1 : 0;
185 a9d11f81 2021-10-08 op }
186 a9d11f81 2021-10-08 op 
187 a9d11f81 2021-10-08 op static int
188 a9d11f81 2021-10-08 op landlock_no_fs(void)
189 a9d11f81 2021-10-08 op {
190 a9d11f81 2021-10-08 op 	int fd;
191 a9d11f81 2021-10-08 op 
192 4ab3b651 2021-11-29 op 	/*
193 4ab3b651 2021-11-29 op 	 * XXX: landlock disabled at runtime, pretend everything's
194 4ab3b651 2021-11-29 op 	 * good.
195 4ab3b651 2021-11-29 op 	 */
196 a9d11f81 2021-10-08 op 	if ((fd = open_landlock()) == -1)
197 4ab3b651 2021-11-29 op 		return 0;
198 a9d11f81 2021-10-08 op 
199 a9d11f81 2021-10-08 op 	return landlock_apply(fd);
200 a9d11f81 2021-10-08 op }
201 a9d11f81 2021-10-08 op 
202 a9d11f81 2021-10-08 op void
203 a9d11f81 2021-10-08 op sandbox_net_process(void)
204 a9d11f81 2021-10-08 op {
205 ed1d237e 2021-11-27 op 	/*
206 ed1d237e 2021-11-27 op 	 * We don't know what paths are required for the TLS stack.
207 ed1d237e 2021-11-27 op 	 * Yes, it sucks.
208 ed1d237e 2021-11-27 op 	 */
209 a9d11f81 2021-10-08 op 	return;
210 a9d11f81 2021-10-08 op }
211 a9d11f81 2021-10-08 op 
212 a9d11f81 2021-10-08 op void
213 a9d11f81 2021-10-08 op sandbox_ui_process(void)
214 a9d11f81 2021-10-08 op {
215 a9d11f81 2021-10-08 op 	if (landlock_no_fs() == -1)
216 a9d11f81 2021-10-08 op 		err(1, "landlock");
217 a9d11f81 2021-10-08 op }
218 a9d11f81 2021-10-08 op 
219 a9d11f81 2021-10-08 op void
220 a9d11f81 2021-10-08 op sandbox_fs_process(void)
221 a9d11f81 2021-10-08 op {
222 a9d11f81 2021-10-08 op 	int fd, rwc;
223 7e76e0ef 2021-11-02 op 	char path[PATH_MAX];
224 a9d11f81 2021-10-08 op 
225 4ab3b651 2021-11-29 op 	/*
226 4ab3b651 2021-11-29 op 	 * XXX: at build-time we found landlock.h but we've just
227 4ab3b651 2021-11-29 op 	 * realized it's not available on this kernel, so do nothing.
228 4ab3b651 2021-11-29 op 	 */
229 a9d11f81 2021-10-08 op 	if ((fd = open_landlock()) == -1)
230 4ab3b651 2021-11-29 op 		return;
231 a9d11f81 2021-10-08 op 
232 a9d11f81 2021-10-08 op 	rwc =	LANDLOCK_ACCESS_FS_READ_FILE	|
233 a9d11f81 2021-10-08 op 		LANDLOCK_ACCESS_FS_READ_DIR	|
234 a9d11f81 2021-10-08 op 		LANDLOCK_ACCESS_FS_WRITE_FILE	|
235 a9d11f81 2021-10-08 op 		LANDLOCK_ACCESS_FS_MAKE_DIR	|
236 a9d11f81 2021-10-08 op 		LANDLOCK_ACCESS_FS_MAKE_REG;
237 a9d11f81 2021-10-08 op 
238 a9d11f81 2021-10-08 op 	if (landlock_unveil(fd, "/tmp", rwc) == -1)
239 a9d11f81 2021-10-08 op 		err(1, "landlock_unveil(/tmp)");
240 a9d11f81 2021-10-08 op 
241 a9d11f81 2021-10-08 op 	strlcpy(path, getenv("HOME"), sizeof(path));
242 a9d11f81 2021-10-08 op 	strlcat(path, "/Downloads", sizeof(path));
243 4380c692 2021-10-08 op 	if (landlock_unveil(fd, path, rwc) == -1 && errno != ENOENT)
244 a9d11f81 2021-10-08 op 		err(1, "landlock_unveil(%s)", path);
245 a9d11f81 2021-10-08 op 
246 a9d11f81 2021-10-08 op 	if (landlock_unveil(fd, config_path_base, rwc) == -1)
247 a9d11f81 2021-10-08 op 		err(1, "landlock_unveil(%s)", config_path_base);
248 a9d11f81 2021-10-08 op 
249 a9d11f81 2021-10-08 op 	if (landlock_unveil(fd, data_path_base, rwc) == -1)
250 a9d11f81 2021-10-08 op 		err(1, "landlock_unveil(%s)", data_path_base);
251 a9d11f81 2021-10-08 op 
252 a9d11f81 2021-10-08 op 	if (landlock_unveil(fd, cache_path_base, rwc) == -1)
253 a9d11f81 2021-10-08 op 		err(1, "landlock_unveil(%s)", cache_path_base);
254 a9d11f81 2021-10-08 op }
255 a9d11f81 2021-10-08 op 
256 68a9b7d2 2021-03-13 op #else
257 68a9b7d2 2021-03-13 op 
258 68a9b7d2 2021-03-13 op #warning "No sandbox for this OS"
259 68a9b7d2 2021-03-13 op 
260 68a9b7d2 2021-03-13 op void
261 17c10c65 2021-07-12 op sandbox_net_process(void)
262 68a9b7d2 2021-03-13 op {
263 68a9b7d2 2021-03-13 op 	return;
264 68a9b7d2 2021-03-13 op }
265 68a9b7d2 2021-03-13 op 
266 35e1f40a 2021-03-14 op void
267 35e1f40a 2021-03-14 op sandbox_ui_process(void)
268 35e1f40a 2021-03-14 op {
269 35e1f40a 2021-03-14 op 	return;
270 35e1f40a 2021-03-14 op }
271 35e1f40a 2021-03-14 op 
272 35e1f40a 2021-03-14 op void
273 35e1f40a 2021-03-14 op sandbox_fs_process(void)
274 35e1f40a 2021-03-14 op {
275 35e1f40a 2021-03-14 op 	return;
276 35e1f40a 2021-03-14 op }
277 35e1f40a 2021-03-14 op 
278 677d90f7 2021-03-12 op #endif