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 * - %LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF: Do not create any log related 83 * to the enforced restrictions coming from future nested domains created by 84 * the caller or its descendants. This should only be set according to a 85 * runtime configuration (i.e. not hardcoded) by programs launching other 86 * unknown or untrusted programs that may create their own Landlock domains 87 * and spam logs. The main use case is for container runtimes to enable users 88 * to mute buggy sandboxed programs for a specific container image. Other use 89 * cases include sandboxer tools and init systems. Unlike 90 * %LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF, 91 * %LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF does not impact the requested 92 * restriction (if any) but only the future nested domains. 93 */ 94 /* clang-format off */ 95 #define LANDLOCK_RESTRICT_SELF_LOG_SAME_EXEC_OFF (1U << 0) 96 #define LANDLOCK_RESTRICT_SELF_LOG_NEW_EXEC_ON (1U << 1) 97 #define LANDLOCK_RESTRICT_SELF_LOG_SUBDOMAINS_OFF (1U << 2) 98 /* clang-format on */ 99 100 /** 101 * enum landlock_rule_type - Landlock rule type 102 * 103 * Argument of sys_landlock_add_rule(). 104 */ 105 enum landlock_rule_type { 106 /** 107 * @LANDLOCK_RULE_PATH_BENEATH: Type of a &struct 108 * landlock_path_beneath_attr . 109 */ 110 LANDLOCK_RULE_PATH_BENEATH = 1, 111 /** 112 * @LANDLOCK_RULE_NET_PORT: Type of a &struct 113 * landlock_net_port_attr . 114 */ 115 LANDLOCK_RULE_NET_PORT, 116 }; 117 118 /** 119 * struct landlock_path_beneath_attr - Path hierarchy definition 120 * 121 * Argument of sys_landlock_add_rule(). 122 */ 123 struct landlock_path_beneath_attr { 124 /** 125 * @allowed_access: Bitmask of allowed actions for this file hierarchy 126 * (cf. `Filesystem flags`_). 127 */ 128 __u64 allowed_access; 129 /** 130 * @parent_fd: File descriptor, preferably opened with ``O_PATH``, 131 * which identifies the parent directory of a file hierarchy, or just a 132 * file. 133 */ 134 __s32 parent_fd; 135 /* 136 * This struct is packed to avoid trailing reserved members. 137 * Cf. security/landlock/syscalls.c:build_check_abi() 138 */ 139 } __attribute__((packed)); 140 141 /** 142 * struct landlock_net_port_attr - Network port definition 143 * 144 * Argument of sys_landlock_add_rule(). 145 */ 146 struct landlock_net_port_attr { 147 /** 148 * @allowed_access: Bitmask of allowed network actions for a port 149 * (cf. `Network flags`_). 150 */ 151 __u64 allowed_access; 152 /** 153 * @port: Network port in host endianness. 154 * 155 * It should be noted that port 0 passed to :manpage:`bind(2)` will bind 156 * to an available port from the ephemeral port range. This can be 157 * configured with the ``/proc/sys/net/ipv4/ip_local_port_range`` sysctl 158 * (also used for IPv6). 159 * 160 * A Landlock rule with port 0 and the ``LANDLOCK_ACCESS_NET_BIND_TCP`` 161 * right means that requesting to bind on port 0 is allowed and it will 162 * automatically translate to binding on the related port range. 163 */ 164 __u64 port; 165 }; 166 167 /** 168 * DOC: fs_access 169 * 170 * A set of actions on kernel objects may be defined by an attribute (e.g. 171 * &struct landlock_path_beneath_attr) including a bitmask of access. 172 * 173 * Filesystem flags 174 * ~~~~~~~~~~~~~~~~ 175 * 176 * These flags enable to restrict a sandboxed process to a set of actions on 177 * files and directories. Files or directories opened before the sandboxing 178 * are not subject to these restrictions. 179 * 180 * The following access rights apply only to files: 181 * 182 * - %LANDLOCK_ACCESS_FS_EXECUTE: Execute a file. 183 * - %LANDLOCK_ACCESS_FS_WRITE_FILE: Open a file with write access. When 184 * opening files for writing, you will often additionally need the 185 * %LANDLOCK_ACCESS_FS_TRUNCATE right. In many cases, these system calls 186 * truncate existing files when overwriting them (e.g., :manpage:`creat(2)`). 187 * - %LANDLOCK_ACCESS_FS_READ_FILE: Open a file with read access. 188 * - %LANDLOCK_ACCESS_FS_TRUNCATE: Truncate a file with :manpage:`truncate(2)`, 189 * :manpage:`ftruncate(2)`, :manpage:`creat(2)`, or :manpage:`open(2)` with 190 * ``O_TRUNC``. This access right is available since the third version of the 191 * Landlock ABI. 192 * 193 * Whether an opened file can be truncated with :manpage:`ftruncate(2)` or used 194 * with `ioctl(2)` is determined during :manpage:`open(2)`, in the same way as 195 * read and write permissions are checked during :manpage:`open(2)` using 196 * %LANDLOCK_ACCESS_FS_READ_FILE and %LANDLOCK_ACCESS_FS_WRITE_FILE. 197 * 198 * A directory can receive access rights related to files or directories. The 199 * following access right is applied to the directory itself, and the 200 * directories beneath it: 201 * 202 * - %LANDLOCK_ACCESS_FS_READ_DIR: Open a directory or list its content. 203 * 204 * However, the following access rights only apply to the content of a 205 * directory, not the directory itself: 206 * 207 * - %LANDLOCK_ACCESS_FS_REMOVE_DIR: Remove an empty directory or rename one. 208 * - %LANDLOCK_ACCESS_FS_REMOVE_FILE: Unlink (or rename) a file. 209 * - %LANDLOCK_ACCESS_FS_MAKE_CHAR: Create (or rename or link) a character 210 * device. 211 * - %LANDLOCK_ACCESS_FS_MAKE_DIR: Create (or rename) a directory. 212 * - %LANDLOCK_ACCESS_FS_MAKE_REG: Create (or rename or link) a regular file. 213 * - %LANDLOCK_ACCESS_FS_MAKE_SOCK: Create (or rename or link) a UNIX domain 214 * socket. 215 * - %LANDLOCK_ACCESS_FS_MAKE_FIFO: Create (or rename or link) a named pipe. 216 * - %LANDLOCK_ACCESS_FS_MAKE_BLOCK: Create (or rename or link) a block device. 217 * - %LANDLOCK_ACCESS_FS_MAKE_SYM: Create (or rename or link) a symbolic link. 218 * - %LANDLOCK_ACCESS_FS_REFER: Link or rename a file from or to a different 219 * directory (i.e. reparent a file hierarchy). 220 * 221 * This access right is available since the second version of the Landlock 222 * ABI. 223 * 224 * This is the only access right which is denied by default by any ruleset, 225 * even if the right is not specified as handled at ruleset creation time. 226 * The only way to make a ruleset grant this right is to explicitly allow it 227 * for a specific directory by adding a matching rule to the ruleset. 228 * 229 * In particular, when using the first Landlock ABI version, Landlock will 230 * always deny attempts to reparent files between different directories. 231 * 232 * In addition to the source and destination directories having the 233 * %LANDLOCK_ACCESS_FS_REFER access right, the attempted link or rename 234 * operation must meet the following constraints: 235 * 236 * * The reparented file may not gain more access rights in the destination 237 * directory than it previously had in the source directory. If this is 238 * attempted, the operation results in an ``EXDEV`` error. 239 * 240 * * When linking or renaming, the ``LANDLOCK_ACCESS_FS_MAKE_*`` right for the 241 * respective file type must be granted for the destination directory. 242 * Otherwise, the operation results in an ``EACCES`` error. 243 * 244 * * When renaming, the ``LANDLOCK_ACCESS_FS_REMOVE_*`` right for the 245 * respective file type must be granted for the source directory. Otherwise, 246 * the operation results in an ``EACCES`` error. 247 * 248 * If multiple requirements are not met, the ``EACCES`` error code takes 249 * precedence over ``EXDEV``. 250 * 251 * The following access right applies both to files and directories: 252 * 253 * - %LANDLOCK_ACCESS_FS_IOCTL_DEV: Invoke :manpage:`ioctl(2)` commands on an opened 254 * character or block device. 255 * 256 * This access right applies to all `ioctl(2)` commands implemented by device 257 * drivers. However, the following common IOCTL commands continue to be 258 * invokable independent of the %LANDLOCK_ACCESS_FS_IOCTL_DEV right: 259 * 260 * * IOCTL commands targeting file descriptors (``FIOCLEX``, ``FIONCLEX``), 261 * * IOCTL commands targeting file descriptions (``FIONBIO``, ``FIOASYNC``), 262 * * IOCTL commands targeting file systems (``FIFREEZE``, ``FITHAW``, 263 * ``FIGETBSZ``, ``FS_IOC_GETFSUUID``, ``FS_IOC_GETFSSYSFSPATH``) 264 * * Some IOCTL commands which do not make sense when used with devices, but 265 * whose implementations are safe and return the right error codes 266 * (``FS_IOC_FIEMAP``, ``FICLONE``, ``FICLONERANGE``, ``FIDEDUPERANGE``) 267 * 268 * This access right is available since the fifth version of the Landlock 269 * ABI. 270 * 271 * .. warning:: 272 * 273 * It is currently not possible to restrict some file-related actions 274 * accessible through these syscall families: :manpage:`chdir(2)`, 275 * :manpage:`stat(2)`, :manpage:`flock(2)`, :manpage:`chmod(2)`, 276 * :manpage:`chown(2)`, :manpage:`setxattr(2)`, :manpage:`utime(2)`, 277 * :manpage:`fcntl(2)`, :manpage:`access(2)`. 278 * Future Landlock evolutions will enable to restrict them. 279 */ 280 /* clang-format off */ 281 #define LANDLOCK_ACCESS_FS_EXECUTE (1ULL << 0) 282 #define LANDLOCK_ACCESS_FS_WRITE_FILE (1ULL << 1) 283 #define LANDLOCK_ACCESS_FS_READ_FILE (1ULL << 2) 284 #define LANDLOCK_ACCESS_FS_READ_DIR (1ULL << 3) 285 #define LANDLOCK_ACCESS_FS_REMOVE_DIR (1ULL << 4) 286 #define LANDLOCK_ACCESS_FS_REMOVE_FILE (1ULL << 5) 287 #define LANDLOCK_ACCESS_FS_MAKE_CHAR (1ULL << 6) 288 #define LANDLOCK_ACCESS_FS_MAKE_DIR (1ULL << 7) 289 #define LANDLOCK_ACCESS_FS_MAKE_REG (1ULL << 8) 290 #define LANDLOCK_ACCESS_FS_MAKE_SOCK (1ULL << 9) 291 #define LANDLOCK_ACCESS_FS_MAKE_FIFO (1ULL << 10) 292 #define LANDLOCK_ACCESS_FS_MAKE_BLOCK (1ULL << 11) 293 #define LANDLOCK_ACCESS_FS_MAKE_SYM (1ULL << 12) 294 #define LANDLOCK_ACCESS_FS_REFER (1ULL << 13) 295 #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) 296 #define LANDLOCK_ACCESS_FS_IOCTL_DEV (1ULL << 15) 297 /* clang-format on */ 298 299 /** 300 * DOC: net_access 301 * 302 * Network flags 303 * ~~~~~~~~~~~~~~~~ 304 * 305 * These flags enable to restrict a sandboxed process to a set of network 306 * actions. 307 * 308 * This is supported since Landlock ABI version 4. 309 * 310 * The following access rights apply to TCP port numbers: 311 * 312 * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. 313 * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to 314 * a remote port. 315 */ 316 /* clang-format off */ 317 #define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) 318 #define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) 319 /* clang-format on */ 320 321 /** 322 * DOC: scope 323 * 324 * Scope flags 325 * ~~~~~~~~~~~ 326 * 327 * These flags enable to isolate a sandboxed process from a set of IPC actions. 328 * Setting a flag for a ruleset will isolate the Landlock domain to forbid 329 * connections to resources outside the domain. 330 * 331 * This is supported since Landlock ABI version 6. 332 * 333 * Scopes: 334 * 335 * - %LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET: Restrict a sandboxed process from 336 * connecting to an abstract UNIX socket created by a process outside the 337 * related Landlock domain (e.g., a parent domain or a non-sandboxed process). 338 * - %LANDLOCK_SCOPE_SIGNAL: Restrict a sandboxed process from sending a signal 339 * to another process outside the domain. 340 */ 341 /* clang-format off */ 342 #define LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET (1ULL << 0) 343 #define LANDLOCK_SCOPE_SIGNAL (1ULL << 1) 344 /* clang-format on*/ 345 346 #endif /* _UAPI_LINUX_LANDLOCK_H */ 347