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