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
49 /*
50 * sys_landlock_create_ruleset() flags:
51 *
52 * - %LANDLOCK_CREATE_RULESET_VERSION: Get the highest supported Landlock ABI
53 * version.
54 */
55 /* clang-format off */
56 #define LANDLOCK_CREATE_RULESET_VERSION (1U << 0)
57 /* clang-format on */
58
59 /**
60 * enum landlock_rule_type - Landlock rule type
61 *
62 * Argument of sys_landlock_add_rule().
63 */
64 enum landlock_rule_type {
65 /**
66 * @LANDLOCK_RULE_PATH_BENEATH: Type of a &struct
67 * landlock_path_beneath_attr .
68 */
69 LANDLOCK_RULE_PATH_BENEATH = 1,
70 /**
71 * @LANDLOCK_RULE_NET_PORT: Type of a &struct
72 * landlock_net_port_attr .
73 */
74 LANDLOCK_RULE_NET_PORT,
75 };
76
77 /**
78 * struct landlock_path_beneath_attr - Path hierarchy definition
79 *
80 * Argument of sys_landlock_add_rule().
81 */
82 struct landlock_path_beneath_attr {
83 /**
84 * @allowed_access: Bitmask of allowed actions for this file hierarchy
85 * (cf. `Filesystem flags`_).
86 */
87 __u64 allowed_access;
88 /**
89 * @parent_fd: File descriptor, preferably opened with ``O_PATH``,
90 * which identifies the parent directory of a file hierarchy, or just a
91 * file.
92 */
93 __s32 parent_fd;
94 /*
95 * This struct is packed to avoid trailing reserved members.
96 * Cf. security/landlock/syscalls.c:build_check_abi()
97 */
98 } __attribute__((packed));
99
100 /**
101 * struct landlock_net_port_attr - Network port definition
102 *
103 * Argument of sys_landlock_add_rule().
104 */
105 struct landlock_net_port_attr {
106 /**
107 * @allowed_access: Bitmask of allowed network actions for a port
108 * (cf. `Network flags`_).
109 */
110 __u64 allowed_access;
111 /**
112 * @port: Network port in host endianness.
113 *
114 * It should be noted that port 0 passed to :manpage:`bind(2)` will bind
115 * to an available port from the ephemeral port range. This can be
116 * configured with the ``/proc/sys/net/ipv4/ip_local_port_range`` sysctl
117 * (also used for IPv6).
118 *
119 * A Landlock rule with port 0 and the ``LANDLOCK_ACCESS_NET_BIND_TCP``
120 * right means that requesting to bind on port 0 is allowed and it will
121 * automatically translate to binding on the related port range.
122 */
123 __u64 port;
124 };
125
126 /**
127 * DOC: fs_access
128 *
129 * A set of actions on kernel objects may be defined by an attribute (e.g.
130 * &struct landlock_path_beneath_attr) including a bitmask of access.
131 *
132 * Filesystem flags
133 * ~~~~~~~~~~~~~~~~
134 *
135 * These flags enable to restrict a sandboxed process to a set of actions on
136 * files and directories. Files or directories opened before the sandboxing
137 * are not subject to these restrictions.
138 *
139 * The following access rights apply only to files:
140 *
141 * - %LANDLOCK_ACCESS_FS_EXECUTE: Execute a file.
142 * - %LANDLOCK_ACCESS_FS_WRITE_FILE: Open a file with write access. When
143 * opening files for writing, you will often additionally need the
144 * %LANDLOCK_ACCESS_FS_TRUNCATE right. In many cases, these system calls
145 * truncate existing files when overwriting them (e.g., :manpage:`creat(2)`).
146 * - %LANDLOCK_ACCESS_FS_READ_FILE: Open a file with read access.
147 * - %LANDLOCK_ACCESS_FS_TRUNCATE: Truncate a file with :manpage:`truncate(2)`,
148 * :manpage:`ftruncate(2)`, :manpage:`creat(2)`, or :manpage:`open(2)` with
149 * ``O_TRUNC``. This access right is available since the third version of the
150 * Landlock ABI.
151 *
152 * Whether an opened file can be truncated with :manpage:`ftruncate(2)` or used
153 * with `ioctl(2)` is determined during :manpage:`open(2)`, in the same way as
154 * read and write permissions are checked during :manpage:`open(2)` using
155 * %LANDLOCK_ACCESS_FS_READ_FILE and %LANDLOCK_ACCESS_FS_WRITE_FILE.
156 *
157 * A directory can receive access rights related to files or directories. The
158 * following access right is applied to the directory itself, and the
159 * directories beneath it:
160 *
161 * - %LANDLOCK_ACCESS_FS_READ_DIR: Open a directory or list its content.
162 *
163 * However, the following access rights only apply to the content of a
164 * directory, not the directory itself:
165 *
166 * - %LANDLOCK_ACCESS_FS_REMOVE_DIR: Remove an empty directory or rename one.
167 * - %LANDLOCK_ACCESS_FS_REMOVE_FILE: Unlink (or rename) a file.
168 * - %LANDLOCK_ACCESS_FS_MAKE_CHAR: Create (or rename or link) a character
169 * device.
170 * - %LANDLOCK_ACCESS_FS_MAKE_DIR: Create (or rename) a directory.
171 * - %LANDLOCK_ACCESS_FS_MAKE_REG: Create (or rename or link) a regular file.
172 * - %LANDLOCK_ACCESS_FS_MAKE_SOCK: Create (or rename or link) a UNIX domain
173 * socket.
174 * - %LANDLOCK_ACCESS_FS_MAKE_FIFO: Create (or rename or link) a named pipe.
175 * - %LANDLOCK_ACCESS_FS_MAKE_BLOCK: Create (or rename or link) a block device.
176 * - %LANDLOCK_ACCESS_FS_MAKE_SYM: Create (or rename or link) a symbolic link.
177 * - %LANDLOCK_ACCESS_FS_REFER: Link or rename a file from or to a different
178 * directory (i.e. reparent a file hierarchy).
179 *
180 * This access right is available since the second version of the Landlock
181 * ABI.
182 *
183 * This is the only access right which is denied by default by any ruleset,
184 * even if the right is not specified as handled at ruleset creation time.
185 * The only way to make a ruleset grant this right is to explicitly allow it
186 * for a specific directory by adding a matching rule to the ruleset.
187 *
188 * In particular, when using the first Landlock ABI version, Landlock will
189 * always deny attempts to reparent files between different directories.
190 *
191 * In addition to the source and destination directories having the
192 * %LANDLOCK_ACCESS_FS_REFER access right, the attempted link or rename
193 * operation must meet the following constraints:
194 *
195 * * The reparented file may not gain more access rights in the destination
196 * directory than it previously had in the source directory. If this is
197 * attempted, the operation results in an ``EXDEV`` error.
198 *
199 * * When linking or renaming, the ``LANDLOCK_ACCESS_FS_MAKE_*`` right for the
200 * respective file type must be granted for the destination directory.
201 * Otherwise, the operation results in an ``EACCES`` error.
202 *
203 * * When renaming, the ``LANDLOCK_ACCESS_FS_REMOVE_*`` right for the
204 * respective file type must be granted for the source directory. Otherwise,
205 * the operation results in an ``EACCES`` error.
206 *
207 * If multiple requirements are not met, the ``EACCES`` error code takes
208 * precedence over ``EXDEV``.
209 *
210 * The following access right applies both to files and directories:
211 *
212 * - %LANDLOCK_ACCESS_FS_IOCTL_DEV: Invoke :manpage:`ioctl(2)` commands on an opened
213 * character or block device.
214 *
215 * This access right applies to all `ioctl(2)` commands implemented by device
216 * drivers. However, the following common IOCTL commands continue to be
217 * invokable independent of the %LANDLOCK_ACCESS_FS_IOCTL_DEV right:
218 *
219 * * IOCTL commands targeting file descriptors (``FIOCLEX``, ``FIONCLEX``),
220 * * IOCTL commands targeting file descriptions (``FIONBIO``, ``FIOASYNC``),
221 * * IOCTL commands targeting file systems (``FIFREEZE``, ``FITHAW``,
222 * ``FIGETBSZ``, ``FS_IOC_GETFSUUID``, ``FS_IOC_GETFSSYSFSPATH``)
223 * * Some IOCTL commands which do not make sense when used with devices, but
224 * whose implementations are safe and return the right error codes
225 * (``FS_IOC_FIEMAP``, ``FICLONE``, ``FICLONERANGE``, ``FIDEDUPERANGE``)
226 *
227 * This access right is available since the fifth version of the Landlock
228 * ABI.
229 *
230 * .. warning::
231 *
232 * It is currently not possible to restrict some file-related actions
233 * accessible through these syscall families: :manpage:`chdir(2)`,
234 * :manpage:`stat(2)`, :manpage:`flock(2)`, :manpage:`chmod(2)`,
235 * :manpage:`chown(2)`, :manpage:`setxattr(2)`, :manpage:`utime(2)`,
236 * :manpage:`fcntl(2)`, :manpage:`access(2)`.
237 * Future Landlock evolutions will enable to restrict them.
238 */
239 /* clang-format off */
240 #define LANDLOCK_ACCESS_FS_EXECUTE (1ULL << 0)
241 #define LANDLOCK_ACCESS_FS_WRITE_FILE (1ULL << 1)
242 #define LANDLOCK_ACCESS_FS_READ_FILE (1ULL << 2)
243 #define LANDLOCK_ACCESS_FS_READ_DIR (1ULL << 3)
244 #define LANDLOCK_ACCESS_FS_REMOVE_DIR (1ULL << 4)
245 #define LANDLOCK_ACCESS_FS_REMOVE_FILE (1ULL << 5)
246 #define LANDLOCK_ACCESS_FS_MAKE_CHAR (1ULL << 6)
247 #define LANDLOCK_ACCESS_FS_MAKE_DIR (1ULL << 7)
248 #define LANDLOCK_ACCESS_FS_MAKE_REG (1ULL << 8)
249 #define LANDLOCK_ACCESS_FS_MAKE_SOCK (1ULL << 9)
250 #define LANDLOCK_ACCESS_FS_MAKE_FIFO (1ULL << 10)
251 #define LANDLOCK_ACCESS_FS_MAKE_BLOCK (1ULL << 11)
252 #define LANDLOCK_ACCESS_FS_MAKE_SYM (1ULL << 12)
253 #define LANDLOCK_ACCESS_FS_REFER (1ULL << 13)
254 #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14)
255 #define LANDLOCK_ACCESS_FS_IOCTL_DEV (1ULL << 15)
256 /* clang-format on */
257
258 /**
259 * DOC: net_access
260 *
261 * Network flags
262 * ~~~~~~~~~~~~~~~~
263 *
264 * These flags enable to restrict a sandboxed process to a set of network
265 * actions. This is supported since the Landlock ABI version 4.
266 *
267 * The following access rights apply to TCP port numbers:
268 *
269 * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port.
270 * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to
271 * a remote port.
272 */
273 /* clang-format off */
274 #define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0)
275 #define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1)
276 /* clang-format on */
277 #endif /* _UAPI_LINUX_LANDLOCK_H */
278
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