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Date:: Sun Apr 24 10:15:32 2022 UTC
Message:: merge the fs into the ui process The previous separation between the fs and ui process wasn't that good. The idea was to have a `ui' process tightly sandboxed, but it was a lie actually. `ui' was one imsg away from making internet connections and accessing data on the disk, so it wasn't really limited in (almost) any way. Furthermore, having to serialize data to/from the fs proc started to become not really maneagable. As a first step to fix this situation, join the fs and ui process.
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  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 f63b8f73 2022-04-24 op 	if (pledge("stdio rpath wpath cpath unix tty", NULL) == -1)
 61 35e1f40a 2021-03-14 op 		err(1, "pledge");
 62 35e1f40a 2021-03-14 op }
 63 35e1f40a 2021-03-14 op 
 64 a9d11f81 2021-10-08 op #elif HAVE_LINUX_LANDLOCK_H
 65 a9d11f81 2021-10-08 op 
 66 a9d11f81 2021-10-08 op #include <linux/landlock.h>
 67 a9d11f81 2021-10-08 op #include <linux/prctl.h>
 68 a9d11f81 2021-10-08 op 
 69 a9d11f81 2021-10-08 op #include <sys/prctl.h>
 70 a9d11f81 2021-10-08 op #include <sys/stat.h>
 71 a9d11f81 2021-10-08 op #include <sys/syscall.h>
 72 a9d11f81 2021-10-08 op 
 73 fced318d 2021-10-08 op #include <errno.h>
 74 a9d11f81 2021-10-08 op #include <fcntl.h>
 75 a9d11f81 2021-10-08 op #include <stdlib.h>
 76 a9d11f81 2021-10-08 op #include <string.h>
 77 a9d11f81 2021-10-08 op #include <unistd.h>
 78 a9d11f81 2021-10-08 op 
 79 a9d11f81 2021-10-08 op /*
 80 a9d11f81 2021-10-08 op  * What's the deal with landlock?  While distro with linux >= 5.13
 81 a9d11f81 2021-10-08 op  * have the struct declarations, libc wrappers are missing.  The
 82 a9d11f81 2021-10-08 op  * sample landlock code provided by the authors includes these "shims"
 83 a9d11f81 2021-10-08 op  * in their example for the landlock API until libc provides them.
 84 a9d11f81 2021-10-08 op  *
 85 a9d11f81 2021-10-08 op  * Linux is such a mess sometimes.  /rant
 86 a9d11f81 2021-10-08 op  */
 87 a9d11f81 2021-10-08 op 
 88 a9d11f81 2021-10-08 op #ifndef landlock_create_ruleset
 89 a9d11f81 2021-10-08 op static inline int
 90 a9d11f81 2021-10-08 op landlock_create_ruleset(const struct landlock_ruleset_attr *attr, size_t size,
 91 a9d11f81 2021-10-08 op     __u32 flags)
 92 a9d11f81 2021-10-08 op {
 93 a9d11f81 2021-10-08 op 	return syscall(__NR_landlock_create_ruleset, attr, size, flags);
 94 a9d11f81 2021-10-08 op }
 95 a9d11f81 2021-10-08 op #endif
 96 a9d11f81 2021-10-08 op 
 97 a9d11f81 2021-10-08 op #ifndef landlock_add_rule
 98 a9d11f81 2021-10-08 op static inline int
 99 a9d11f81 2021-10-08 op landlock_add_rule(int ruleset_fd, enum landlock_rule_type type,
100 a9d11f81 2021-10-08 op     const void *attr, __u32 flags)
101 a9d11f81 2021-10-08 op {
102 a9d11f81 2021-10-08 op 	return syscall(__NR_landlock_add_rule, ruleset_fd, type, attr, flags);
103 a9d11f81 2021-10-08 op }
104 a9d11f81 2021-10-08 op #endif
105 a9d11f81 2021-10-08 op 
106 a9d11f81 2021-10-08 op #ifndef landlock_restrict_self
107 a9d11f81 2021-10-08 op static inline int
108 a9d11f81 2021-10-08 op landlock_restrict_self(int ruleset_fd, __u32 flags)
109 a9d11f81 2021-10-08 op {
110 a9d11f81 2021-10-08 op 	return syscall(__NR_landlock_restrict_self, ruleset_fd, flags);
111 a9d11f81 2021-10-08 op }
112 a9d11f81 2021-10-08 op #endif
113 a9d11f81 2021-10-08 op 
114 a9d11f81 2021-10-08 op static int
115 a9d11f81 2021-10-08 op open_landlock(void)
116 a9d11f81 2021-10-08 op {
117 4ab3b651 2021-11-29 op 	int fd;
118 a9d11f81 2021-10-08 op 	struct landlock_ruleset_attr attr = {
119 35ae81fd 2022-02-10 op 		.handled_access_fs =	LANDLOCK_ACCESS_FS_EXECUTE |
120 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_READ_FILE |
121 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_READ_DIR |
122 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_WRITE_FILE |
123 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_REMOVE_DIR |
124 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_REMOVE_FILE |
125 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_CHAR |
126 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_DIR |
127 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_REG |
128 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_SOCK |
129 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_FIFO |
130 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_BLOCK |
131 35ae81fd 2022-02-10 op 					LANDLOCK_ACCESS_FS_MAKE_SYM,
132 a9d11f81 2021-10-08 op 	};
133 a9d11f81 2021-10-08 op 
134 4ab3b651 2021-11-29 op 	fd = landlock_create_ruleset(&attr, sizeof(attr), 0);
135 4ab3b651 2021-11-29 op 	if (fd == -1) {
136 4ab3b651 2021-11-29 op 		switch (errno) {
137 4ab3b651 2021-11-29 op 		case ENOSYS:
138 4ab3b651 2021-11-29 op 		case EOPNOTSUPP:
139 4ab3b651 2021-11-29 op 			return -1;
140 4ab3b651 2021-11-29 op 		default:
141 4ab3b651 2021-11-29 op 			err(1, "can't create landlock ruleset");
142 4ab3b651 2021-11-29 op 		}
143 4ab3b651 2021-11-29 op 	}
144 4ab3b651 2021-11-29 op 	return fd;
145 a9d11f81 2021-10-08 op }
146 a9d11f81 2021-10-08 op 
147 a9d11f81 2021-10-08 op static int
148 a9d11f81 2021-10-08 op landlock_unveil(int landlock_fd, const char *path, int perms)
149 a9d11f81 2021-10-08 op {
150 a9d11f81 2021-10-08 op 	struct landlock_path_beneath_attr pb;
151 a9d11f81 2021-10-08 op 	int err, saved_errno;
152 a9d11f81 2021-10-08 op 
153 a9d11f81 2021-10-08 op 	pb.allowed_access = perms;
154 a9d11f81 2021-10-08 op 
155 a9d11f81 2021-10-08 op 	if ((pb.parent_fd = open(path, O_PATH)) == -1)
156 a9d11f81 2021-10-08 op 		return -1;
157 a9d11f81 2021-10-08 op 
158 a9d11f81 2021-10-08 op 	err = landlock_add_rule(landlock_fd, LANDLOCK_RULE_PATH_BENEATH,
159 a9d11f81 2021-10-08 op 	    &pb, 0);
160 a9d11f81 2021-10-08 op 	saved_errno = errno;
161 a9d11f81 2021-10-08 op 	close(pb.parent_fd);
162 a9d11f81 2021-10-08 op 	errno = saved_errno;
163 a9d11f81 2021-10-08 op 	return err ? -1 : 0;
164 a9d11f81 2021-10-08 op }
165 a9d11f81 2021-10-08 op 
166 a9d11f81 2021-10-08 op static int
167 a9d11f81 2021-10-08 op landlock_apply(int fd)
168 a9d11f81 2021-10-08 op {
169 a9d11f81 2021-10-08 op 	int r, saved_errno;
170 a9d11f81 2021-10-08 op 
171 a9d11f81 2021-10-08 op 	if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) == -1)
172 a9d11f81 2021-10-08 op 		err(1, "%s: prctl(PR_SET_NO_NEW_PRIVS)", __func__);
173 a9d11f81 2021-10-08 op 
174 a9d11f81 2021-10-08 op 	r = landlock_restrict_self(fd, 0);
175 a9d11f81 2021-10-08 op 	saved_errno = errno;
176 a9d11f81 2021-10-08 op 	close(fd);
177 a9d11f81 2021-10-08 op 	errno = saved_errno;
178 a9d11f81 2021-10-08 op 	return r ? -1 : 0;
179 a9d11f81 2021-10-08 op }
180 a9d11f81 2021-10-08 op 
181 a9d11f81 2021-10-08 op static int
182 a9d11f81 2021-10-08 op landlock_no_fs(void)
183 a9d11f81 2021-10-08 op {
184 a9d11f81 2021-10-08 op 	int fd;
185 a9d11f81 2021-10-08 op 
186 4ab3b651 2021-11-29 op 	/*
187 4ab3b651 2021-11-29 op 	 * XXX: landlock disabled at runtime, pretend everything's
188 4ab3b651 2021-11-29 op 	 * good.
189 4ab3b651 2021-11-29 op 	 */
190 a9d11f81 2021-10-08 op 	if ((fd = open_landlock()) == -1)
191 4ab3b651 2021-11-29 op 		return 0;
192 a9d11f81 2021-10-08 op 
193 a9d11f81 2021-10-08 op 	return landlock_apply(fd);
194 a9d11f81 2021-10-08 op }
195 a9d11f81 2021-10-08 op 
196 a9d11f81 2021-10-08 op void
197 a9d11f81 2021-10-08 op sandbox_net_process(void)
198 a9d11f81 2021-10-08 op {
199 ed1d237e 2021-11-27 op 	/*
200 ed1d237e 2021-11-27 op 	 * We don't know what paths are required for the TLS stack.
201 ed1d237e 2021-11-27 op 	 * Yes, it sucks.
202 ed1d237e 2021-11-27 op 	 */
203 a9d11f81 2021-10-08 op 	return;
204 a9d11f81 2021-10-08 op }
205 a9d11f81 2021-10-08 op 
206 a9d11f81 2021-10-08 op void
207 a9d11f81 2021-10-08 op sandbox_ui_process(void)
208 a9d11f81 2021-10-08 op {
209 4ab3b651 2021-11-29 op 	/*
210 f63b8f73 2022-04-24 op 	 * Needs to be able to read files *and* execute programs,
211 f63b8f73 2022-04-24 op 	 * can't be sandboxed.
212 4ab3b651 2021-11-29 op 	 */
213 f63b8f73 2022-04-24 op 	return;
214 a9d11f81 2021-10-08 op }
215 a9d11f81 2021-10-08 op 
216 68a9b7d2 2021-03-13 op #else
217 68a9b7d2 2021-03-13 op 
218 68a9b7d2 2021-03-13 op #warning "No sandbox for this OS"
219 68a9b7d2 2021-03-13 op 
220 68a9b7d2 2021-03-13 op void
221 17c10c65 2021-07-12 op sandbox_net_process(void)
222 68a9b7d2 2021-03-13 op {
223 68a9b7d2 2021-03-13 op 	return;
224 68a9b7d2 2021-03-13 op }
225 68a9b7d2 2021-03-13 op 
226 35e1f40a 2021-03-14 op void
227 35e1f40a 2021-03-14 op sandbox_ui_process(void)
228 35e1f40a 2021-03-14 op {
229 35e1f40a 2021-03-14 op 	return;
230 35e1f40a 2021-03-14 op }
231 35e1f40a 2021-03-14 op 
232 677d90f7 2021-03-12 op #endif