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 de2a69bb 2021-05-17 op 	if (pledge("stdio tty 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 a9d11f81 2021-10-08 op 		.handled_access_fs =	LANDLOCK_ACCESS_FS_READ_FILE	|
126 a9d11f81 2021-10-08 op 					LANDLOCK_ACCESS_FS_READ_DIR	|
127 a9d11f81 2021-10-08 op 					LANDLOCK_ACCESS_FS_WRITE_FILE	|
128 a9d11f81 2021-10-08 op 					LANDLOCK_ACCESS_FS_MAKE_DIR	|
129 a9d11f81 2021-10-08 op 					LANDLOCK_ACCESS_FS_MAKE_REG,
130 a9d11f81 2021-10-08 op 	};
131 a9d11f81 2021-10-08 op 
132 4ab3b651 2021-11-29 op 	fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
133 4ab3b651 2021-11-29 op 	if (fd == -1) {
134 4ab3b651 2021-11-29 op 		switch (errno) {
135 4ab3b651 2021-11-29 op 		case ENOSYS:
136 4ab3b651 2021-11-29 op 		case EOPNOTSUPP:
137 4ab3b651 2021-11-29 op 			return -1;
138 4ab3b651 2021-11-29 op 		default:
139 4ab3b651 2021-11-29 op 			err(1, "can't create landlock ruleset");
140 4ab3b651 2021-11-29 op 		}
141 4ab3b651 2021-11-29 op 	}
142 4ab3b651 2021-11-29 op 	return fd;
143 a9d11f81 2021-10-08 op }
144 a9d11f81 2021-10-08 op 
145 a9d11f81 2021-10-08 op static int
146 a9d11f81 2021-10-08 op landlock_unveil(int landlock_fd, const char *path, int perms)
147 a9d11f81 2021-10-08 op {
148 a9d11f81 2021-10-08 op 	struct landlock_path_beneath_attr pb;
149 a9d11f81 2021-10-08 op 	int err, saved_errno;
150 a9d11f81 2021-10-08 op 
151 a9d11f81 2021-10-08 op 	pb.allowed_access = perms;
152 a9d11f81 2021-10-08 op 
153 a9d11f81 2021-10-08 op 	if ((pb.parent_fd = open(path, O_PATH)) == -1)
154 a9d11f81 2021-10-08 op 		return -1;
155 a9d11f81 2021-10-08 op 
156 a9d11f81 2021-10-08 op 	err = landlock_add_rule(landlock_fd, LANDLOCK_RULE_PATH_BENEATH,
157 a9d11f81 2021-10-08 op 	    &pb, 0);
158 a9d11f81 2021-10-08 op 	saved_errno = errno;
159 a9d11f81 2021-10-08 op 	close(pb.parent_fd);
160 a9d11f81 2021-10-08 op 	errno = saved_errno;
161 a9d11f81 2021-10-08 op 	return err ? -1 : 0;
162 a9d11f81 2021-10-08 op }
163 a9d11f81 2021-10-08 op 
164 a9d11f81 2021-10-08 op static int
165 a9d11f81 2021-10-08 op landlock_apply(int fd)
166 a9d11f81 2021-10-08 op {
167 a9d11f81 2021-10-08 op 	int r, saved_errno;
168 a9d11f81 2021-10-08 op 
169 a9d11f81 2021-10-08 op 	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1)
170 a9d11f81 2021-10-08 op 		err(1, "%s: prctl(PR_SET_NO_NEW_PRIVS)", __func__);
171 a9d11f81 2021-10-08 op 
172 a9d11f81 2021-10-08 op 	r = landlock_restrict_self(fd, 0);
173 a9d11f81 2021-10-08 op 	saved_errno = errno;
174 a9d11f81 2021-10-08 op 	close(fd);
175 a9d11f81 2021-10-08 op 	errno = saved_errno;
176 a9d11f81 2021-10-08 op 	return r ? -1 : 0;
177 a9d11f81 2021-10-08 op }
178 a9d11f81 2021-10-08 op 
179 a9d11f81 2021-10-08 op static int
180 a9d11f81 2021-10-08 op landlock_no_fs(void)
181 a9d11f81 2021-10-08 op {
182 a9d11f81 2021-10-08 op 	int fd;
183 a9d11f81 2021-10-08 op 
184 4ab3b651 2021-11-29 op 	/*
185 4ab3b651 2021-11-29 op 	 * XXX: landlock disabled at runtime, pretend everything's
186 4ab3b651 2021-11-29 op 	 * good.
187 4ab3b651 2021-11-29 op 	 */
188 a9d11f81 2021-10-08 op 	if ((fd = open_landlock()) == -1)
189 4ab3b651 2021-11-29 op 		return 0;
190 a9d11f81 2021-10-08 op 
191 a9d11f81 2021-10-08 op 	return landlock_apply(fd);
192 a9d11f81 2021-10-08 op }
193 a9d11f81 2021-10-08 op 
194 a9d11f81 2021-10-08 op void
195 a9d11f81 2021-10-08 op sandbox_net_process(void)
196 a9d11f81 2021-10-08 op {
197 ed1d237e 2021-11-27 op 	/*
198 ed1d237e 2021-11-27 op 	 * We don't know what paths are required for the TLS stack.
199 ed1d237e 2021-11-27 op 	 * Yes, it sucks.
200 ed1d237e 2021-11-27 op 	 */
201 a9d11f81 2021-10-08 op 	return;
202 a9d11f81 2021-10-08 op }
203 a9d11f81 2021-10-08 op 
204 a9d11f81 2021-10-08 op void
205 a9d11f81 2021-10-08 op sandbox_ui_process(void)
206 a9d11f81 2021-10-08 op {
207 a9d11f81 2021-10-08 op 	if (landlock_no_fs() == -1)
208 a9d11f81 2021-10-08 op 		err(1, "landlock");
209 a9d11f81 2021-10-08 op }
210 a9d11f81 2021-10-08 op 
211 a9d11f81 2021-10-08 op void
212 a9d11f81 2021-10-08 op sandbox_fs_process(void)
213 a9d11f81 2021-10-08 op {
214 a9d11f81 2021-10-08 op 	int fd, rwc;
215 7e76e0ef 2021-11-02 op 	char path[PATH_MAX];
216 a9d11f81 2021-10-08 op 
217 4ab3b651 2021-11-29 op 	/*
218 4ab3b651 2021-11-29 op 	 * XXX: at build-time we found landlock.h but we've just
219 4ab3b651 2021-11-29 op 	 * realized it's not available on this kernel, so do nothing.
220 4ab3b651 2021-11-29 op 	 */
221 a9d11f81 2021-10-08 op 	if ((fd = open_landlock()) == -1)
222 4ab3b651 2021-11-29 op 		return;
223 a9d11f81 2021-10-08 op 
224 a9d11f81 2021-10-08 op 	rwc =	LANDLOCK_ACCESS_FS_READ_FILE	|
225 a9d11f81 2021-10-08 op 		LANDLOCK_ACCESS_FS_READ_DIR	|
226 a9d11f81 2021-10-08 op 		LANDLOCK_ACCESS_FS_WRITE_FILE	|
227 a9d11f81 2021-10-08 op 		LANDLOCK_ACCESS_FS_MAKE_DIR	|
228 a9d11f81 2021-10-08 op 		LANDLOCK_ACCESS_FS_MAKE_REG;
229 a9d11f81 2021-10-08 op 
230 a9d11f81 2021-10-08 op 	if (landlock_unveil(fd, "/tmp", rwc) == -1)
231 a9d11f81 2021-10-08 op 		err(1, "landlock_unveil(/tmp)");
232 a9d11f81 2021-10-08 op 
233 a9d11f81 2021-10-08 op 	strlcpy(path, getenv("HOME"), sizeof(path));
234 a9d11f81 2021-10-08 op 	strlcat(path, "/Downloads", sizeof(path));
235 4380c692 2021-10-08 op 	if (landlock_unveil(fd, path, rwc) == -1 && errno != ENOENT)
236 a9d11f81 2021-10-08 op 		err(1, "landlock_unveil(%s)", path);
237 a9d11f81 2021-10-08 op 
238 a9d11f81 2021-10-08 op 	if (landlock_unveil(fd, config_path_base, rwc) == -1)
239 a9d11f81 2021-10-08 op 		err(1, "landlock_unveil(%s)", config_path_base);
240 a9d11f81 2021-10-08 op 
241 a9d11f81 2021-10-08 op 	if (landlock_unveil(fd, data_path_base, rwc) == -1)
242 a9d11f81 2021-10-08 op 		err(1, "landlock_unveil(%s)", data_path_base);
243 a9d11f81 2021-10-08 op 
244 a9d11f81 2021-10-08 op 	if (landlock_unveil(fd, cache_path_base, rwc) == -1)
245 a9d11f81 2021-10-08 op 		err(1, "landlock_unveil(%s)", cache_path_base);
246 a9d11f81 2021-10-08 op }
247 a9d11f81 2021-10-08 op 
248 68a9b7d2 2021-03-13 op #else
249 68a9b7d2 2021-03-13 op 
250 68a9b7d2 2021-03-13 op #warning "No sandbox for this OS"
251 68a9b7d2 2021-03-13 op 
252 68a9b7d2 2021-03-13 op void
253 17c10c65 2021-07-12 op sandbox_net_process(void)
254 68a9b7d2 2021-03-13 op {
255 68a9b7d2 2021-03-13 op 	return;
256 68a9b7d2 2021-03-13 op }
257 68a9b7d2 2021-03-13 op 
258 35e1f40a 2021-03-14 op void
259 35e1f40a 2021-03-14 op sandbox_ui_process(void)
260 35e1f40a 2021-03-14 op {
261 35e1f40a 2021-03-14 op 	return;
262 35e1f40a 2021-03-14 op }
263 35e1f40a 2021-03-14 op 
264 35e1f40a 2021-03-14 op void
265 35e1f40a 2021-03-14 op sandbox_fs_process(void)
266 35e1f40a 2021-03-14 op {
267 35e1f40a 2021-03-14 op 	return;
268 35e1f40a 2021-03-14 op }
269 35e1f40a 2021-03-14 op 
270 677d90f7 2021-03-12 op #endif