1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2 /* 3 * Landlock - User space API 4 * 5 * Copyright © 2017-2020 Mickaël Salaün <[email protected]> 6 * Copyright © 2018-2020 ANSSI 7 * Copyright © 2021-2025 Microsoft Corporation 8 */ 9 10 #ifndef _UAPI_LINUX_LANDLOCK_H 11 #define _UAPI_LINUX_LANDLOCK_H 12 13 #include <linux/types.h> 14 15 /** 16 * struct landlock_ruleset_attr - Ruleset definition. 17 * 18 * Argument of sys_landlock_create_ruleset(). 19 * 20 * This structure defines a set of *handled access rights*, a set of actions on 21 * different object types, which should be denied by default when the ruleset is 22 * enacted. Vice versa, access rights that are not specifically listed here are 23 * not going to be denied by this ruleset when it is enacted. 24 * 25 * For historical reasons, the %LANDLOCK_ACCESS_FS_REFER right is always denied 26 * by default, even when its bit is not set in @handled_access_fs. In order to 27 * add new rules with this access right, the bit must still be set explicitly 28 * (cf. `Filesystem flags`_). 29 * 30 * The explicit listing of *handled access rights* is required for backwards 31 * compatibility reasons. In most use cases, processes that use Landlock will 32 * *handle* a wide range or all access rights that they know about at build time 33 * (and that they have tested with a kernel that supported them all). 34 * 35 * This structure can grow in future Landlock versions. 36 */ 37 struct landlock_ruleset_attr { 38 /** 39 * @handled_access_fs: Bitmask of handled filesystem actions 40 * (cf. `Filesystem flags`_). 41 */ 42 __u64 handled_access_fs; 43 /** 44 * @handled_access_net: Bitmask of handled network actions (cf. `Network 45 * flags`_). 46 */ 47 __u64 handled_access_net; 48 /** 49 * @scoped: Bitmask of scopes (cf. `Scope flags`_) 50 * restricting a Landlock domain from accessing outside 51 * resources (e.g. IPCs). 52 */ 53 __u64 scoped; 54 }; 55 56 /* 57 * sys_landlock_create_ruleset() flags: 58 * 59 * - %LANDLOCK_CREATE_RULESET_VERSION: Get the highest supported Landlock ABI 60 * version. 61 * - %LANDLOCK_CREATE_RULESET_ERRATA: Get a bitmask of fixed issues. 62 */ 63 /* clang-format off */ 64 #define LANDLOCK_CREATE_RULESET_VERSION (1U << 0) 65 #define LANDLOCK_CREATE_RULESET_ERRATA (1U << 1) 66 /* clang-format on */ 67 68 /* 69 * sys_landlock_restrict_self() flags: 70 * 71 * - %LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF: Do not create any log related to the 72 * enforced restrictions. This should only be set by tools launching unknown 73 * or untrusted programs (e.g. a sandbox tool, container runtime, system 74 * service manager). Because programs sandboxing themselves should fix any 75 * denied access, they should not set this flag to be aware of potential 76 * issues reported by system's logs (i.e. audit). 77 * - %LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON: Explicitly ask to continue 78 * logging denied access requests even after an :manpage:`execve(2)` call. 79 * This flag should only be set if all the programs than can legitimately be 80 * executed will not try to request a denied access (which could spam audit 81 * logs). 82 */ 83 /* clang-format off */ 84 #define LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF (1U << 0) 85 #define LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON (1U << 1) 86 /* clang-format on */ 87 88 /** 89 * enum landlock_rule_type - Landlock rule type 90 * 91 * Argument of sys_landlock_add_rule(). 92 */ 93 enum landlock_rule_type { 94 /** 95 * @LANDLOCK_RULE_PATH_BENEATH: Type of a &struct 96 * landlock_path_beneath_attr . 97 */ 98 LANDLOCK_RULE_PATH_BENEATH = 1, 99 /** 100 * @LANDLOCK_RULE_NET_PORT: Type of a &struct 101 * landlock_net_port_attr . 102 */ 103 LANDLOCK_RULE_NET_PORT, 104 }; 105 106 /** 107 * struct landlock_path_beneath_attr - Path hierarchy definition 108 * 109 * Argument of sys_landlock_add_rule(). 110 */ 111 struct landlock_path_beneath_attr { 112 /** 113 * @allowed_access: Bitmask of allowed actions for this file hierarchy 114 * (cf. `Filesystem flags`_). 115 */ 116 __u64 allowed_access; 117 /** 118 * @parent_fd: File descriptor, preferably opened with ``O_PATH``, 119 * which identifies the parent directory of a file hierarchy, or just a 120 * file. 121 */ 122 __s32 parent_fd; 123 /* 124 * This struct is packed to avoid trailing reserved members. 125 * Cf. security/landlock/syscalls.c:build_check_abi() 126 */ 127 } __attribute__((packed)); 128 129 /** 130 * struct landlock_net_port_attr - Network port definition 131 * 132 * Argument of sys_landlock_add_rule(). 133 */ 134 struct landlock_net_port_attr { 135 /** 136 * @allowed_access: Bitmask of allowed network actions for a port 137 * (cf. `Network flags`_). 138 */ 139 __u64 allowed_access; 140 /** 141 * @port: Network port in host endianness. 142 * 143 * It should be noted that port 0 passed to :manpage:`bind(2)` will bind 144 * to an available port from the ephemeral port range. This can be 145 * configured with the ``/proc/sys/net/ipv4/ip_local_port_range`` sysctl 146 * (also used for IPv6). 147 * 148 * A Landlock rule with port 0 and the ``LANDLOCK_ACCESS_NET_BIND_TCP`` 149 * right means that requesting to bind on port 0 is allowed and it will 150 * automatically translate to binding on the related port range. 151 */ 152 __u64 port; 153 }; 154 155 /** 156 * DOC: fs_access 157 * 158 * A set of actions on kernel objects may be defined by an attribute (e.g. 159 * &struct landlock_path_beneath_attr) including a bitmask of access. 160 * 161 * Filesystem flags 162 * ~~~~~~~~~~~~~~~~ 163 * 164 * These flags enable to restrict a sandboxed process to a set of actions on 165 * files and directories. Files or directories opened before the sandboxing 166 * are not subject to these restrictions. 167 * 168 * The following access rights apply only to files: 169 * 170 * - %LANDLOCK_ACCESS_FS_EXECUTE: Execute a file. 171 * - %LANDLOCK_ACCESS_FS_WRITE_FILE: Open a file with write access. When 172 * opening files for writing, you will often additionally need the 173 * %LANDLOCK_ACCESS_FS_TRUNCATE right. In many cases, these system calls 174 * truncate existing files when overwriting them (e.g., :manpage:`creat(2)`). 175 * - %LANDLOCK_ACCESS_FS_READ_FILE: Open a file with read access. 176 * - %LANDLOCK_ACCESS_FS_TRUNCATE: Truncate a file with :manpage:`truncate(2)`, 177 * :manpage:`ftruncate(2)`, :manpage:`creat(2)`, or :manpage:`open(2)` with 178 * ``O_TRUNC``. This access right is available since the third version of the 179 * Landlock ABI. 180 * 181 * Whether an opened file can be truncated with :manpage:`ftruncate(2)` or used 182 * with `ioctl(2)` is determined during :manpage:`open(2)`, in the same way as 183 * read and write permissions are checked during :manpage:`open(2)` using 184 * %LANDLOCK_ACCESS_FS_READ_FILE and %LANDLOCK_ACCESS_FS_WRITE_FILE. 185 * 186 * A directory can receive access rights related to files or directories. The 187 * following access right is applied to the directory itself, and the 188 * directories beneath it: 189 * 190 * - %LANDLOCK_ACCESS_FS_READ_DIR: Open a directory or list its content. 191 * 192 * However, the following access rights only apply to the content of a 193 * directory, not the directory itself: 194 * 195 * - %LANDLOCK_ACCESS_FS_REMOVE_DIR: Remove an empty directory or rename one. 196 * - %LANDLOCK_ACCESS_FS_REMOVE_FILE: Unlink (or rename) a file. 197 * - %LANDLOCK_ACCESS_FS_MAKE_CHAR: Create (or rename or link) a character 198 * device. 199 * - %LANDLOCK_ACCESS_FS_MAKE_DIR: Create (or rename) a directory. 200 * - %LANDLOCK_ACCESS_FS_MAKE_REG: Create (or rename or link) a regular file. 201 * - %LANDLOCK_ACCESS_FS_MAKE_SOCK: Create (or rename or link) a UNIX domain 202 * socket. 203 * - %LANDLOCK_ACCESS_FS_MAKE_FIFO: Create (or rename or link) a named pipe. 204 * - %LANDLOCK_ACCESS_FS_MAKE_BLOCK: Create (or rename or link) a block device. 205 * - %LANDLOCK_ACCESS_FS_MAKE_SYM: Create (or rename or link) a symbolic link. 206 * - %LANDLOCK_ACCESS_FS_REFER: Link or rename a file from or to a different 207 * directory (i.e. reparent a file hierarchy). 208 * 209 * This access right is available since the second version of the Landlock 210 * ABI. 211 * 212 * This is the only access right which is denied by default by any ruleset, 213 * even if the right is not specified as handled at ruleset creation time. 214 * The only way to make a ruleset grant this right is to explicitly allow it 215 * for a specific directory by adding a matching rule to the ruleset. 216 * 217 * In particular, when using the first Landlock ABI version, Landlock will 218 * always deny attempts to reparent files between different directories. 219 * 220 * In addition to the source and destination directories having the 221 * %LANDLOCK_ACCESS_FS_REFER access right, the attempted link or rename 222 * operation must meet the following constraints: 223 * 224 * * The reparented file may not gain more access rights in the destination 225 * directory than it previously had in the source directory. If this is 226 * attempted, the operation results in an ``EXDEV`` error. 227 * 228 * * When linking or renaming, the ``LANDLOCK_ACCESS_FS_MAKE_*`` right for the 229 * respective file type must be granted for the destination directory. 230 * Otherwise, the operation results in an ``EACCES`` error. 231 * 232 * * When renaming, the ``LANDLOCK_ACCESS_FS_REMOVE_*`` right for the 233 * respective file type must be granted for the source directory. Otherwise, 234 * the operation results in an ``EACCES`` error. 235 * 236 * If multiple requirements are not met, the ``EACCES`` error code takes 237 * precedence over ``EXDEV``. 238 * 239 * The following access right applies both to files and directories: 240 * 241 * - %LANDLOCK_ACCESS_FS_IOCTL_DEV: Invoke :manpage:`ioctl(2)` commands on an opened 242 * character or block device. 243 * 244 * This access right applies to all `ioctl(2)` commands implemented by device 245 * drivers. However, the following common IOCTL commands continue to be 246 * invokable independent of the %LANDLOCK_ACCESS_FS_IOCTL_DEV right: 247 * 248 * * IOCTL commands targeting file descriptors (``FIOCLEX``, ``FIONCLEX``), 249 * * IOCTL commands targeting file descriptions (``FIONBIO``, ``FIOASYNC``), 250 * * IOCTL commands targeting file systems (``FIFREEZE``, ``FITHAW``, 251 * ``FIGETBSZ``, ``FS_IOC_GETFSUUID``, ``FS_IOC_GETFSSYSFSPATH``) 252 * * Some IOCTL commands which do not make sense when used with devices, but 253 * whose implementations are safe and return the right error codes 254 * (``FS_IOC_FIEMAP``, ``FICLONE``, ``FICLONERANGE``, ``FIDEDUPERANGE``) 255 * 256 * This access right is available since the fifth version of the Landlock 257 * ABI. 258 * 259 * .. warning:: 260 * 261 * It is currently not possible to restrict some file-related actions 262 * accessible through these syscall families: :manpage:`chdir(2)`, 263 * :manpage:`stat(2)`, :manpage:`flock(2)`, :manpage:`chmod(2)`, 264 * :manpage:`chown(2)`, :manpage:`setxattr(2)`, :manpage:`utime(2)`, 265 * :manpage:`fcntl(2)`, :manpage:`access(2)`. 266 * Future Landlock evolutions will enable to restrict them. 267 */ 268 /* clang-format off */ 269 #define LANDLOCK_ACCESS_FS_EXECUTE (1ULL << 0) 270 #define LANDLOCK_ACCESS_FS_WRITE_FILE (1ULL << 1) 271 #define LANDLOCK_ACCESS_FS_READ_FILE (1ULL << 2) 272 #define LANDLOCK_ACCESS_FS_READ_DIR (1ULL << 3) 273 #define LANDLOCK_ACCESS_FS_REMOVE_DIR (1ULL << 4) 274 #define LANDLOCK_ACCESS_FS_REMOVE_FILE (1ULL << 5) 275 #define LANDLOCK_ACCESS_FS_MAKE_CHAR (1ULL << 6) 276 #define LANDLOCK_ACCESS_FS_MAKE_DIR (1ULL << 7) 277 #define LANDLOCK_ACCESS_FS_MAKE_REG (1ULL << 8) 278 #define LANDLOCK_ACCESS_FS_MAKE_SOCK (1ULL << 9) 279 #define LANDLOCK_ACCESS_FS_MAKE_FIFO (1ULL << 10) 280 #define LANDLOCK_ACCESS_FS_MAKE_BLOCK (1ULL << 11) 281 #define LANDLOCK_ACCESS_FS_MAKE_SYM (1ULL << 12) 282 #define LANDLOCK_ACCESS_FS_REFER (1ULL << 13) 283 #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) 284 #define LANDLOCK_ACCESS_FS_IOCTL_DEV (1ULL << 15) 285 /* clang-format on */ 286 287 /** 288 * DOC: net_access 289 * 290 * Network flags 291 * ~~~~~~~~~~~~~~~~ 292 * 293 * These flags enable to restrict a sandboxed process to a set of network 294 * actions. 295 * 296 * This is supported since Landlock ABI version 4. 297 * 298 * The following access rights apply to TCP port numbers: 299 * 300 * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. 301 * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to 302 * a remote port. 303 */ 304 /* clang-format off */ 305 #define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) 306 #define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) 307 /* clang-format on */ 308 309 /** 310 * DOC: scope 311 * 312 * Scope flags 313 * ~~~~~~~~~~~ 314 * 315 * These flags enable to isolate a sandboxed process from a set of IPC actions. 316 * Setting a flag for a ruleset will isolate the Landlock domain to forbid 317 * connections to resources outside the domain. 318 * 319 * This is supported since Landlock ABI version 6. 320 * 321 * Scopes: 322 * 323 * - %LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET: Restrict a sandboxed process from 324 * connecting to an abstract UNIX socket created by a process outside the 325 * related Landlock domain (e.g., a parent domain or a non-sandboxed process). 326 * - %LANDLOCK_SCOPE_SIGNAL: Restrict a sandboxed process from sending a signal 327 * to another process outside the domain. 328 */ 329 /* clang-format off */ 330 #define LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET (1ULL << 0) 331 #define LANDLOCK_SCOPE_SIGNAL (1ULL << 1) 332 /* clang-format on*/ 333 334 #endif /* _UAPI_LINUX_LANDLOCK_H */ 335