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 f63b8f73 2022-04-24 op #include <limits.h>
 20 f63b8f73 2022-04-24 op 
 21 4b877649 2021-10-07 op #include "fs.h"
 22 754622a2 2021-03-15 op #include "telescope.h"
 23 677d90f7 2021-03-12 op 
 24 677d90f7 2021-03-12 op #ifdef __OpenBSD__
 25 677d90f7 2021-03-12 op 
 26 fced318d 2021-10-08 op # include <errno.h>
 27 35e1f40a 2021-03-14 op # include <stdlib.h>
 28 35e1f40a 2021-03-14 op # include <string.h>
 29 2b1f38ab 2021-03-13 op # include <unistd.h>
 30 2b1f38ab 2021-03-13 op 
 31 677d90f7 2021-03-12 op void
 32 17c10c65 2021-07-12 op sandbox_net_process(void)
 33 677d90f7 2021-03-12 op {
 34 677d90f7 2021-03-12 op 	if (pledge("stdio inet dns", NULL) == -1)
 35 677d90f7 2021-03-12 op 		err(1, "pledge");
 36 677d90f7 2021-03-12 op }
 37 677d90f7 2021-03-12 op 
 38 b1d4d01b 2021-03-14 op void
 39 b1d4d01b 2021-03-14 op sandbox_ui_process(void)
 40 b1d4d01b 2021-03-14 op {
 41 35e1f40a 2021-03-14 op 	char path[PATH_MAX];
 42 35e1f40a 2021-03-14 op 
 43 de2a69bb 2021-05-17 op 	if (unveil("/tmp", "rwc") == -1)
 44 e9cb759e 2021-10-08 op 		err(1, "unveil(/tmp)");
 45 35e1f40a 2021-03-14 op 
 46 35e1f40a 2021-03-14 op 	strlcpy(path, getenv("HOME"), sizeof(path));
 47 35e1f40a 2021-03-14 op 	strlcat(path, "/Downloads", sizeof(path));
 48 4380c692 2021-10-08 op 	if (unveil(path, "rwc") == -1 && errno != ENOENT)
 49 fd0beb53 2021-10-07 op 		err(1, "unveil(%s)", path);
 50 35e1f40a 2021-03-14 op 
 51 4b877649 2021-10-07 op 	if (unveil(config_path_base, "rwc") == -1)
 52 fd0beb53 2021-10-07 op 		err(1, "unveil(%s)", config_path_base);
 53 35e1f40a 2021-03-14 op 
 54 4b877649 2021-10-07 op 	if (unveil(data_path_base, "rwc") == -1)
 55 fd0beb53 2021-10-07 op 		err(1, "unveil(%s)", data_path_base);
 56 4b877649 2021-10-07 op 
 57 4b877649 2021-10-07 op 	if (unveil(cache_path_base, "rwc") == -1)
 58 fd0beb53 2021-10-07 op 		err(1, "unveil(%s)", cache_path_base);
 59 4b877649 2021-10-07 op 
 60 8f90b214 2022-08-16 op 	if (unveil("/bin/sh", "rx") == -1)
 61 8f90b214 2022-08-16 op 		err(1, "unveil(xdg-open)");
 62 8f90b214 2022-08-16 op 
 63 8f90b214 2022-08-16 op 	if (pledge("stdio rpath wpath cpath unix tty proc exec",
 64 8f90b214 2022-08-16 op 	    NULL) == -1)
 65 35e1f40a 2021-03-14 op 		err(1, "pledge");
 66 35e1f40a 2021-03-14 op }
 67 35e1f40a 2021-03-14 op 
 68 a9d11f81 2021-10-08 op #elif HAVE_LINUX_LANDLOCK_H
 69 a9d11f81 2021-10-08 op 
 70 a9d11f81 2021-10-08 op #include <linux/landlock.h>
 71 a9d11f81 2021-10-08 op 
 72 a9d11f81 2021-10-08 op #include <sys/prctl.h>
 73 a9d11f81 2021-10-08 op #include <sys/stat.h>
 74 a9d11f81 2021-10-08 op #include <sys/syscall.h>
 75 a9d11f81 2021-10-08 op 
 76 fced318d 2021-10-08 op #include <errno.h>
 77 a9d11f81 2021-10-08 op #include <fcntl.h>
 78 a9d11f81 2021-10-08 op #include <stdlib.h>
 79 a9d11f81 2021-10-08 op #include <string.h>
 80 a9d11f81 2021-10-08 op #include <unistd.h>
 81 a9d11f81 2021-10-08 op 
 82 a9d11f81 2021-10-08 op /*
 83 a9d11f81 2021-10-08 op  * What's the deal with landlock?  While distro with linux >= 5.13
 84 a9d11f81 2021-10-08 op  * have the struct declarations, libc wrappers are missing.  The
 85 a9d11f81 2021-10-08 op  * sample landlock code provided by the authors includes these "shims"
 86 a9d11f81 2021-10-08 op  * in their example for the landlock API until libc provides them.
 87 a9d11f81 2021-10-08 op  *
 88 a9d11f81 2021-10-08 op  * Linux is such a mess sometimes.  /rant
 89 a9d11f81 2021-10-08 op  */
 90 a9d11f81 2021-10-08 op 
 91 a9d11f81 2021-10-08 op #ifndef landlock_create_ruleset
 92 a9d11f81 2021-10-08 op static inline int
 93 a9d11f81 2021-10-08 op landlock_create_ruleset(const struct landlock_ruleset_attr *attr, size_t size,
 94 a9d11f81 2021-10-08 op     __u32 flags)
 95 a9d11f81 2021-10-08 op {
 96 a9d11f81 2021-10-08 op 	return syscall(__NR_landlock_create_ruleset, attr, size, flags);
 97 a9d11f81 2021-10-08 op }
 98 a9d11f81 2021-10-08 op #endif
 99 a9d11f81 2021-10-08 op 
100 a9d11f81 2021-10-08 op #ifndef landlock_add_rule
101 a9d11f81 2021-10-08 op static inline int
102 a9d11f81 2021-10-08 op landlock_add_rule(int ruleset_fd, enum landlock_rule_type type,
103 a9d11f81 2021-10-08 op     const void *attr, __u32 flags)
104 a9d11f81 2021-10-08 op {
105 a9d11f81 2021-10-08 op 	return syscall(__NR_landlock_add_rule, ruleset_fd, type, attr, flags);
106 a9d11f81 2021-10-08 op }
107 a9d11f81 2021-10-08 op #endif
108 a9d11f81 2021-10-08 op 
109 a9d11f81 2021-10-08 op #ifndef landlock_restrict_self
110 a9d11f81 2021-10-08 op static inline int
111 a9d11f81 2021-10-08 op landlock_restrict_self(int ruleset_fd, __u32 flags)
112 a9d11f81 2021-10-08 op {
113 a9d11f81 2021-10-08 op 	return syscall(__NR_landlock_restrict_self, ruleset_fd, flags);
114 a9d11f81 2021-10-08 op }
115 a9d11f81 2021-10-08 op #endif
116 a9d11f81 2021-10-08 op 
117 a9d11f81 2021-10-08 op static int
118 a9d11f81 2021-10-08 op open_landlock(void)
119 a9d11f81 2021-10-08 op {
120 4ab3b651 2021-11-29 op 	int fd;
121 a9d11f81 2021-10-08 op 	struct landlock_ruleset_attr attr = {
122 35ae81fd 2022-02-10 op 		.handled_access_fs =	LANDLOCK_ACCESS_FS_EXECUTE |
123 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_READ_FILE |
124 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_READ_DIR |
125 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_WRITE_FILE |
126 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_REMOVE_DIR |
127 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_REMOVE_FILE |
128 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_CHAR |
129 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_DIR |
130 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_REG |
131 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_SOCK |
132 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_FIFO |
133 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_BLOCK |
134 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_SYM,
135 a9d11f81 2021-10-08 op 	};
136 a9d11f81 2021-10-08 op 
137 4ab3b651 2021-11-29 op 	fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
138 4ab3b651 2021-11-29 op 	if (fd == -1) {
139 4ab3b651 2021-11-29 op 		switch (errno) {
140 4ab3b651 2021-11-29 op 		case ENOSYS:
141 4ab3b651 2021-11-29 op 		case EOPNOTSUPP:
142 4ab3b651 2021-11-29 op 			return -1;
143 4ab3b651 2021-11-29 op 		default:
144 4ab3b651 2021-11-29 op 			err(1, "can't create landlock ruleset");
145 4ab3b651 2021-11-29 op 		}
146 4ab3b651 2021-11-29 op 	}
147 4ab3b651 2021-11-29 op 	return fd;
148 a9d11f81 2021-10-08 op }
149 a9d11f81 2021-10-08 op 
150 a9d11f81 2021-10-08 op static int
151 a9d11f81 2021-10-08 op landlock_unveil(int landlock_fd, const char *path, int perms)
152 a9d11f81 2021-10-08 op {
153 a9d11f81 2021-10-08 op 	struct landlock_path_beneath_attr pb;
154 a9d11f81 2021-10-08 op 	int err, saved_errno;
155 a9d11f81 2021-10-08 op 
156 a9d11f81 2021-10-08 op 	pb.allowed_access = perms;
157 a9d11f81 2021-10-08 op 
158 a9d11f81 2021-10-08 op 	if ((pb.parent_fd = open(path, O_PATH)) == -1)
159 a9d11f81 2021-10-08 op 		return -1;
160 a9d11f81 2021-10-08 op 
161 a9d11f81 2021-10-08 op 	err = landlock_add_rule(landlock_fd, LANDLOCK_RULE_PATH_BENEATH,
162 a9d11f81 2021-10-08 op 	    &pb, 0);
163 a9d11f81 2021-10-08 op 	saved_errno = errno;
164 a9d11f81 2021-10-08 op 	close(pb.parent_fd);
165 a9d11f81 2021-10-08 op 	errno = saved_errno;
166 a9d11f81 2021-10-08 op 	return err ? -1 : 0;
167 a9d11f81 2021-10-08 op }
168 a9d11f81 2021-10-08 op 
169 a9d11f81 2021-10-08 op static int
170 a9d11f81 2021-10-08 op landlock_apply(int fd)
171 a9d11f81 2021-10-08 op {
172 a9d11f81 2021-10-08 op 	int r, saved_errno;
173 a9d11f81 2021-10-08 op 
174 a9d11f81 2021-10-08 op 	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1)
175 a9d11f81 2021-10-08 op 		err(1, "%s: prctl(PR_SET_NO_NEW_PRIVS)", __func__);
176 a9d11f81 2021-10-08 op 
177 a9d11f81 2021-10-08 op 	r = landlock_restrict_self(fd, 0);
178 a9d11f81 2021-10-08 op 	saved_errno = errno;
179 a9d11f81 2021-10-08 op 	close(fd);
180 a9d11f81 2021-10-08 op 	errno = saved_errno;
181 a9d11f81 2021-10-08 op 	return r ? -1 : 0;
182 a9d11f81 2021-10-08 op }
183 a9d11f81 2021-10-08 op 
184 a9d11f81 2021-10-08 op static int
185 a9d11f81 2021-10-08 op landlock_no_fs(void)
186 a9d11f81 2021-10-08 op {
187 a9d11f81 2021-10-08 op 	int fd;
188 a9d11f81 2021-10-08 op 
189 4ab3b651 2021-11-29 op 	/*
190 4ab3b651 2021-11-29 op 	 * XXX: landlock disabled at runtime, pretend everything's
191 4ab3b651 2021-11-29 op 	 * good.
192 4ab3b651 2021-11-29 op 	 */
193 a9d11f81 2021-10-08 op 	if ((fd = open_landlock()) == -1)
194 4ab3b651 2021-11-29 op 		return 0;
195 a9d11f81 2021-10-08 op 
196 a9d11f81 2021-10-08 op 	return landlock_apply(fd);
197 a9d11f81 2021-10-08 op }
198 a9d11f81 2021-10-08 op 
199 a9d11f81 2021-10-08 op void
200 a9d11f81 2021-10-08 op sandbox_net_process(void)
201 a9d11f81 2021-10-08 op {
202 ed1d237e 2021-11-27 op 	/*
203 ed1d237e 2021-11-27 op 	 * We don't know what paths are required for the TLS stack.
204 ed1d237e 2021-11-27 op 	 * Yes, it sucks.
205 ed1d237e 2021-11-27 op 	 */
206 a9d11f81 2021-10-08 op 	return;
207 a9d11f81 2021-10-08 op }
208 a9d11f81 2021-10-08 op 
209 a9d11f81 2021-10-08 op void
210 a9d11f81 2021-10-08 op sandbox_ui_process(void)
211 a9d11f81 2021-10-08 op {
212 4ab3b651 2021-11-29 op 	/*
213 f63b8f73 2022-04-24 op 	 * Needs to be able to read files *and* execute programs,
214 f63b8f73 2022-04-24 op 	 * can't be sandboxed.
215 4ab3b651 2021-11-29 op 	 */
216 f63b8f73 2022-04-24 op 	return;
217 a9d11f81 2021-10-08 op }
218 a9d11f81 2021-10-08 op 
219 68a9b7d2 2021-03-13 op #else
220 68a9b7d2 2021-03-13 op 
221 68a9b7d2 2021-03-13 op #warning "No sandbox for this OS"
222 68a9b7d2 2021-03-13 op 
223 68a9b7d2 2021-03-13 op void
224 17c10c65 2021-07-12 op sandbox_net_process(void)
225 68a9b7d2 2021-03-13 op {
226 68a9b7d2 2021-03-13 op 	return;
227 68a9b7d2 2021-03-13 op }
228 68a9b7d2 2021-03-13 op 
229 35e1f40a 2021-03-14 op void
230 35e1f40a 2021-03-14 op sandbox_ui_process(void)
231 35e1f40a 2021-03-14 op {
232 35e1f40a 2021-03-14 op 	return;
233 35e1f40a 2021-03-14 op }
234 35e1f40a 2021-03-14 op 
235 677d90f7 2021-03-12 op #endif