1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 /*
3 * Landlock - User space API
4 *
5 * Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
6 * Copyright © 2018-2020 ANSSI
7 */
8
9 #ifndef _UAPI_LINUX_LANDLOCK_H
10 #define _UAPI_LINUX_LANDLOCK_H
11
12 #include <linux/types.h>
13
14 /**
15 * struct landlock_ruleset_attr - Ruleset definition.
16 *
17 * Argument of sys_landlock_create_ruleset().
18 *
19 * This structure defines a set of *handled access rights*, a set of actions on
20 * different object types, which should be denied by default when the ruleset is
21 * enacted. Vice versa, access rights that are not specifically listed here are
22 * not going to be denied by this ruleset when it is enacted.
23 *
24 * For historical reasons, the %LANDLOCK_ACCESS_FS_REFER right is always denied
25 * by default, even when its bit is not set in @handled_access_fs. In order to
26 * add new rules with this access right, the bit must still be set explicitly
27 * (cf. `Filesystem flags`_).
28 *
29 * The explicit listing of *handled access rights* is required for backwards
30 * compatibility reasons. In most use cases, processes that use Landlock will
31 * *handle* a wide range or all access rights that they know about at build time
32 * (and that they have tested with a kernel that supported them all).
33 *
34 * This structure can grow in future Landlock versions.
35 */
36 struct landlock_ruleset_attr {
37 /**
38 * @handled_access_fs: Bitmask of handled filesystem actions
39 * (cf. `Filesystem flags`_).
40 */
41 __u64 handled_access_fs;
42 /**
43 * @handled_access_net: Bitmask of handled network actions (cf. `Network
44 * flags`_).
45 */
46 __u64 handled_access_net;
47 /**
48 * @scoped: Bitmask of scopes (cf. `Scope flags`_)
49 * restricting a Landlock domain from accessing outside
50 * resources (e.g. IPCs).
51 */
52 __u64 scoped;
53 };
54
55 /*
56 * sys_landlock_create_ruleset() flags:
57 *
58 * - %LANDLOCK_CREATE_RULESET_VERSION: Get the highest supported Landlock ABI
59 * version.
60 */
61 /* clang-format off */
62 #define LANDLOCK_CREATE_RULESET_VERSION (1U << 0)
63 /* clang-format on */
64
65 /**
66 * enum landlock_rule_type - Landlock rule type
67 *
68 * Argument of sys_landlock_add_rule().
69 */
70 enum landlock_rule_type {
71 /**
72 * @LANDLOCK_RULE_PATH_BENEATH: Type of a &struct
73 * landlock_path_beneath_attr .
74 */
75 LANDLOCK_RULE_PATH_BENEATH = 1,
76 /**
77 * @LANDLOCK_RULE_NET_PORT: Type of a &struct
78 * landlock_net_port_attr .
79 */
80 LANDLOCK_RULE_NET_PORT,
81 };
82
83 /**
84 * struct landlock_path_beneath_attr - Path hierarchy definition
85 *
86 * Argument of sys_landlock_add_rule().
87 */
88 struct landlock_path_beneath_attr {
89 /**
90 * @allowed_access: Bitmask of allowed actions for this file hierarchy
91 * (cf. `Filesystem flags`_).
92 */
93 __u64 allowed_access;
94 /**
95 * @parent_fd: File descriptor, preferably opened with ``O_PATH``,
96 * which identifies the parent directory of a file hierarchy, or just a
97 * file.
98 */
99 __s32 parent_fd;
100 /*
101 * This struct is packed to avoid trailing reserved members.
102 * Cf. security/landlock/syscalls.c:build_check_abi()
103 */
104 } __attribute__((packed));
105
106 /**
107 * struct landlock_net_port_attr - Network port definition
108 *
109 * Argument of sys_landlock_add_rule().
110 */
111 struct landlock_net_port_attr {
112 /**
113 * @allowed_access: Bitmask of allowed network actions for a port
114 * (cf. `Network flags`_).
115 */
116 __u64 allowed_access;
117 /**
118 * @port: Network port in host endianness.
119 *
120 * It should be noted that port 0 passed to :manpage:`bind(2)` will bind
121 * to an available port from the ephemeral port range. This can be
122 * configured with the ``/proc/sys/net/ipv4/ip_local_port_range`` sysctl
123 * (also used for IPv6).
124 *
125 * A Landlock rule with port 0 and the ``LANDLOCK_ACCESS_NET_BIND_TCP``
126 * right means that requesting to bind on port 0 is allowed and it will
127 * automatically translate to binding on the related port range.
128 */
129 __u64 port;
130 };
131
132 /**
133 * DOC: fs_access
134 *
135 * A set of actions on kernel objects may be defined by an attribute (e.g.
136 * &struct landlock_path_beneath_attr) including a bitmask of access.
137 *
138 * Filesystem flags
139 * ~~~~~~~~~~~~~~~~
140 *
141 * These flags enable to restrict a sandboxed process to a set of actions on
142 * files and directories. Files or directories opened before the sandboxing
143 * are not subject to these restrictions.
144 *
145 * The following access rights apply only to files:
146 *
147 * - %LANDLOCK_ACCESS_FS_EXECUTE: Execute a file.
148 * - %LANDLOCK_ACCESS_FS_WRITE_FILE: Open a file with write access. When
149 * opening files for writing, you will often additionally need the
150 * %LANDLOCK_ACCESS_FS_TRUNCATE right. In many cases, these system calls
151 * truncate existing files when overwriting them (e.g., :manpage:`creat(2)`).
152 * - %LANDLOCK_ACCESS_FS_READ_FILE: Open a file with read access.
153 * - %LANDLOCK_ACCESS_FS_TRUNCATE: Truncate a file with :manpage:`truncate(2)`,
154 * :manpage:`ftruncate(2)`, :manpage:`creat(2)`, or :manpage:`open(2)` with
155 * ``O_TRUNC``. This access right is available since the third version of the
156 * Landlock ABI.
157 *
158 * Whether an opened file can be truncated with :manpage:`ftruncate(2)` or used
159 * with `ioctl(2)` is determined during :manpage:`open(2)`, in the same way as
160 * read and write permissions are checked during :manpage:`open(2)` using
161 * %LANDLOCK_ACCESS_FS_READ_FILE and %LANDLOCK_ACCESS_FS_WRITE_FILE.
162 *
163 * A directory can receive access rights related to files or directories. The
164 * following access right is applied to the directory itself, and the
165 * directories beneath it:
166 *
167 * - %LANDLOCK_ACCESS_FS_READ_DIR: Open a directory or list its content.
168 *
169 * However, the following access rights only apply to the content of a
170 * directory, not the directory itself:
171 *
172 * - %LANDLOCK_ACCESS_FS_REMOVE_DIR: Remove an empty directory or rename one.
173 * - %LANDLOCK_ACCESS_FS_REMOVE_FILE: Unlink (or rename) a file.
174 * - %LANDLOCK_ACCESS_FS_MAKE_CHAR: Create (or rename or link) a character
175 * device.
176 * - %LANDLOCK_ACCESS_FS_MAKE_DIR: Create (or rename) a directory.
177 * - %LANDLOCK_ACCESS_FS_MAKE_REG: Create (or rename or link) a regular file.
178 * - %LANDLOCK_ACCESS_FS_MAKE_SOCK: Create (or rename or link) a UNIX domain
179 * socket.
180 * - %LANDLOCK_ACCESS_FS_MAKE_FIFO: Create (or rename or link) a named pipe.
181 * - %LANDLOCK_ACCESS_FS_MAKE_BLOCK: Create (or rename or link) a block device.
182 * - %LANDLOCK_ACCESS_FS_MAKE_SYM: Create (or rename or link) a symbolic link.
183 * - %LANDLOCK_ACCESS_FS_REFER: Link or rename a file from or to a different
184 * directory (i.e. reparent a file hierarchy).
185 *
186 * This access right is available since the second version of the Landlock
187 * ABI.
188 *
189 * This is the only access right which is denied by default by any ruleset,
190 * even if the right is not specified as handled at ruleset creation time.
191 * The only way to make a ruleset grant this right is to explicitly allow it
192 * for a specific directory by adding a matching rule to the ruleset.
193 *
194 * In particular, when using the first Landlock ABI version, Landlock will
195 * always deny attempts to reparent files between different directories.
196 *
197 * In addition to the source and destination directories having the
198 * %LANDLOCK_ACCESS_FS_REFER access right, the attempted link or rename
199 * operation must meet the following constraints:
200 *
201 * * The reparented file may not gain more access rights in the destination
202 * directory than it previously had in the source directory. If this is
203 * attempted, the operation results in an ``EXDEV`` error.
204 *
205 * * When linking or renaming, the ``LANDLOCK_ACCESS_FS_MAKE_*`` right for the
206 * respective file type must be granted for the destination directory.
207 * Otherwise, the operation results in an ``EACCES`` error.
208 *
209 * * When renaming, the ``LANDLOCK_ACCESS_FS_REMOVE_*`` right for the
210 * respective file type must be granted for the source directory. Otherwise,
211 * the operation results in an ``EACCES`` error.
212 *
213 * If multiple requirements are not met, the ``EACCES`` error code takes
214 * precedence over ``EXDEV``.
215 *
216 * The following access right applies both to files and directories:
217 *
218 * - %LANDLOCK_ACCESS_FS_IOCTL_DEV: Invoke :manpage:`ioctl(2)` commands on an opened
219 * character or block device.
220 *
221 * This access right applies to all `ioctl(2)` commands implemented by device
222 * drivers. However, the following common IOCTL commands continue to be
223 * invokable independent of the %LANDLOCK_ACCESS_FS_IOCTL_DEV right:
224 *
225 * * IOCTL commands targeting file descriptors (``FIOCLEX``, ``FIONCLEX``),
226 * * IOCTL commands targeting file descriptions (``FIONBIO``, ``FIOASYNC``),
227 * * IOCTL commands targeting file systems (``FIFREEZE``, ``FITHAW``,
228 * ``FIGETBSZ``, ``FS_IOC_GETFSUUID``, ``FS_IOC_GETFSSYSFSPATH``)
229 * * Some IOCTL commands which do not make sense when used with devices, but
230 * whose implementations are safe and return the right error codes
231 * (``FS_IOC_FIEMAP``, ``FICLONE``, ``FICLONERANGE``, ``FIDEDUPERANGE``)
232 *
233 * This access right is available since the fifth version of the Landlock
234 * ABI.
235 *
236 * .. warning::
237 *
238 * It is currently not possible to restrict some file-related actions
239 * accessible through these syscall families: :manpage:`chdir(2)`,
240 * :manpage:`stat(2)`, :manpage:`flock(2)`, :manpage:`chmod(2)`,
241 * :manpage:`chown(2)`, :manpage:`setxattr(2)`, :manpage:`utime(2)`,
242 * :manpage:`fcntl(2)`, :manpage:`access(2)`.
243 * Future Landlock evolutions will enable to restrict them.
244 */
245 /* clang-format off */
246 #define LANDLOCK_ACCESS_FS_EXECUTE (1ULL << 0)
247 #define LANDLOCK_ACCESS_FS_WRITE_FILE (1ULL << 1)
248 #define LANDLOCK_ACCESS_FS_READ_FILE (1ULL << 2)
249 #define LANDLOCK_ACCESS_FS_READ_DIR (1ULL << 3)
250 #define LANDLOCK_ACCESS_FS_REMOVE_DIR (1ULL << 4)
251 #define LANDLOCK_ACCESS_FS_REMOVE_FILE (1ULL << 5)
252 #define LANDLOCK_ACCESS_FS_MAKE_CHAR (1ULL << 6)
253 #define LANDLOCK_ACCESS_FS_MAKE_DIR (1ULL << 7)
254 #define LANDLOCK_ACCESS_FS_MAKE_REG (1ULL << 8)
255 #define LANDLOCK_ACCESS_FS_MAKE_SOCK (1ULL << 9)
256 #define LANDLOCK_ACCESS_FS_MAKE_FIFO (1ULL << 10)
257 #define LANDLOCK_ACCESS_FS_MAKE_BLOCK (1ULL << 11)
258 #define LANDLOCK_ACCESS_FS_MAKE_SYM (1ULL << 12)
259 #define LANDLOCK_ACCESS_FS_REFER (1ULL << 13)
260 #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14)
261 #define LANDLOCK_ACCESS_FS_IOCTL_DEV (1ULL << 15)
262 /* clang-format on */
263
264 /**
265 * DOC: net_access
266 *
267 * Network flags
268 * ~~~~~~~~~~~~~~~~
269 *
270 * These flags enable to restrict a sandboxed process to a set of network
271 * actions. This is supported since the Landlock ABI version 4.
272 *
273 * The following access rights apply to TCP port numbers:
274 *
275 * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port.
276 * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to
277 * a remote port.
278 */
279 /* clang-format off */
280 #define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0)
281 #define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1)
282 /* clang-format on */
283
284 /**
285 * DOC: scope
286 *
287 * Scope flags
288 * ~~~~~~~~~~~
289 *
290 * These flags enable to isolate a sandboxed process from a set of IPC actions.
291 * Setting a flag for a ruleset will isolate the Landlock domain to forbid
292 * connections to resources outside the domain.
293 *
294 * Scopes:
295 *
296 * - %LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET: Restrict a sandboxed process from
297 * connecting to an abstract UNIX socket created by a process outside the
298 * related Landlock domain (e.g. a parent domain or a non-sandboxed process).
299 * - %LANDLOCK_SCOPE_SIGNAL: Restrict a sandboxed process from sending a signal
300 * to another process outside the domain.
301 */
302 /* clang-format off */
303 #define LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET (1ULL << 0)
304 #define LANDLOCK_SCOPE_SIGNAL (1ULL << 1)
305 /* clang-format on*/
306
307 #endif /* _UAPI_LINUX_LANDLOCK_H */
308
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