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 */ 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 * - %LANDLOCK_CREATE_RULESET_ERRATA: Get a bitmask of fixed issues. 61 */ 62 /* clang-format off */ 63 #define LANDLOCK_CREATE_RULESET_VERSION (1U << 0) 64 #define LANDLOCK_CREATE_RULESET_ERRATA (1U << 1) 65 /* clang-format on */ 66 67 /** 68 * enum landlock_rule_type - Landlock rule type 69 * 70 * Argument of sys_landlock_add_rule(). 71 */ 72 enum landlock_rule_type { 73 /** 74 * @LANDLOCK_RULE_PATH_BENEATH: Type of a &struct 75 * landlock_path_beneath_attr . 76 */ 77 LANDLOCK_RULE_PATH_BENEATH = 1, 78 /** 79 * @LANDLOCK_RULE_NET_PORT: Type of a &struct 80 * landlock_net_port_attr . 81 */ 82 LANDLOCK_RULE_NET_PORT, 83 }; 84 85 /** 86 * struct landlock_path_beneath_attr - Path hierarchy definition 87 * 88 * Argument of sys_landlock_add_rule(). 89 */ 90 struct landlock_path_beneath_attr { 91 /** 92 * @allowed_access: Bitmask of allowed actions for this file hierarchy 93 * (cf. `Filesystem flags`_). 94 */ 95 __u64 allowed_access; 96 /** 97 * @parent_fd: File descriptor, preferably opened with ``O_PATH``, 98 * which identifies the parent directory of a file hierarchy, or just a 99 * file. 100 */ 101 __s32 parent_fd; 102 /* 103 * This struct is packed to avoid trailing reserved members. 104 * Cf. security/landlock/syscalls.c:build_check_abi() 105 */ 106 } __attribute__((packed)); 107 108 /** 109 * struct landlock_net_port_attr - Network port definition 110 * 111 * Argument of sys_landlock_add_rule(). 112 */ 113 struct landlock_net_port_attr { 114 /** 115 * @allowed_access: Bitmask of allowed network actions for a port 116 * (cf. `Network flags`_). 117 */ 118 __u64 allowed_access; 119 /** 120 * @port: Network port in host endianness. 121 * 122 * It should be noted that port 0 passed to :manpage:`bind(2)` will bind 123 * to an available port from the ephemeral port range. This can be 124 * configured with the ``/proc/sys/net/ipv4/ip_local_port_range`` sysctl 125 * (also used for IPv6). 126 * 127 * A Landlock rule with port 0 and the ``LANDLOCK_ACCESS_NET_BIND_TCP`` 128 * right means that requesting to bind on port 0 is allowed and it will 129 * automatically translate to binding on the related port range. 130 */ 131 __u64 port; 132 }; 133 134 /** 135 * DOC: fs_access 136 * 137 * A set of actions on kernel objects may be defined by an attribute (e.g. 138 * &struct landlock_path_beneath_attr) including a bitmask of access. 139 * 140 * Filesystem flags 141 * ~~~~~~~~~~~~~~~~ 142 * 143 * These flags enable to restrict a sandboxed process to a set of actions on 144 * files and directories. Files or directories opened before the sandboxing 145 * are not subject to these restrictions. 146 * 147 * The following access rights apply only to files: 148 * 149 * - %LANDLOCK_ACCESS_FS_EXECUTE: Execute a file. 150 * - %LANDLOCK_ACCESS_FS_WRITE_FILE: Open a file with write access. When 151 * opening files for writing, you will often additionally need the 152 * %LANDLOCK_ACCESS_FS_TRUNCATE right. In many cases, these system calls 153 * truncate existing files when overwriting them (e.g., :manpage:`creat(2)`). 154 * - %LANDLOCK_ACCESS_FS_READ_FILE: Open a file with read access. 155 * - %LANDLOCK_ACCESS_FS_TRUNCATE: Truncate a file with :manpage:`truncate(2)`, 156 * :manpage:`ftruncate(2)`, :manpage:`creat(2)`, or :manpage:`open(2)` with 157 * ``O_TRUNC``. This access right is available since the third version of the 158 * Landlock ABI. 159 * 160 * Whether an opened file can be truncated with :manpage:`ftruncate(2)` or used 161 * with `ioctl(2)` is determined during :manpage:`open(2)`, in the same way as 162 * read and write permissions are checked during :manpage:`open(2)` using 163 * %LANDLOCK_ACCESS_FS_READ_FILE and %LANDLOCK_ACCESS_FS_WRITE_FILE. 164 * 165 * A directory can receive access rights related to files or directories. The 166 * following access right is applied to the directory itself, and the 167 * directories beneath it: 168 * 169 * - %LANDLOCK_ACCESS_FS_READ_DIR: Open a directory or list its content. 170 * 171 * However, the following access rights only apply to the content of a 172 * directory, not the directory itself: 173 * 174 * - %LANDLOCK_ACCESS_FS_REMOVE_DIR: Remove an empty directory or rename one. 175 * - %LANDLOCK_ACCESS_FS_REMOVE_FILE: Unlink (or rename) a file. 176 * - %LANDLOCK_ACCESS_FS_MAKE_CHAR: Create (or rename or link) a character 177 * device. 178 * - %LANDLOCK_ACCESS_FS_MAKE_DIR: Create (or rename) a directory. 179 * - %LANDLOCK_ACCESS_FS_MAKE_REG: Create (or rename or link) a regular file. 180 * - %LANDLOCK_ACCESS_FS_MAKE_SOCK: Create (or rename or link) a UNIX domain 181 * socket. 182 * - %LANDLOCK_ACCESS_FS_MAKE_FIFO: Create (or rename or link) a named pipe. 183 * - %LANDLOCK_ACCESS_FS_MAKE_BLOCK: Create (or rename or link) a block device. 184 * - %LANDLOCK_ACCESS_FS_MAKE_SYM: Create (or rename or link) a symbolic link. 185 * - %LANDLOCK_ACCESS_FS_REFER: Link or rename a file from or to a different 186 * directory (i.e. reparent a file hierarchy). 187 * 188 * This access right is available since the second version of the Landlock 189 * ABI. 190 * 191 * This is the only access right which is denied by default by any ruleset, 192 * even if the right is not specified as handled at ruleset creation time. 193 * The only way to make a ruleset grant this right is to explicitly allow it 194 * for a specific directory by adding a matching rule to the ruleset. 195 * 196 * In particular, when using the first Landlock ABI version, Landlock will 197 * always deny attempts to reparent files between different directories. 198 * 199 * In addition to the source and destination directories having the 200 * %LANDLOCK_ACCESS_FS_REFER access right, the attempted link or rename 201 * operation must meet the following constraints: 202 * 203 * * The reparented file may not gain more access rights in the destination 204 * directory than it previously had in the source directory. If this is 205 * attempted, the operation results in an ``EXDEV`` error. 206 * 207 * * When linking or renaming, the ``LANDLOCK_ACCESS_FS_MAKE_*`` right for the 208 * respective file type must be granted for the destination directory. 209 * Otherwise, the operation results in an ``EACCES`` error. 210 * 211 * * When renaming, the ``LANDLOCK_ACCESS_FS_REMOVE_*`` right for the 212 * respective file type must be granted for the source directory. Otherwise, 213 * the operation results in an ``EACCES`` error. 214 * 215 * If multiple requirements are not met, the ``EACCES`` error code takes 216 * precedence over ``EXDEV``. 217 * 218 * The following access right applies both to files and directories: 219 * 220 * - %LANDLOCK_ACCESS_FS_IOCTL_DEV: Invoke :manpage:`ioctl(2)` commands on an opened 221 * character or block device. 222 * 223 * This access right applies to all `ioctl(2)` commands implemented by device 224 * drivers. However, the following common IOCTL commands continue to be 225 * invokable independent of the %LANDLOCK_ACCESS_FS_IOCTL_DEV right: 226 * 227 * * IOCTL commands targeting file descriptors (``FIOCLEX``, ``FIONCLEX``), 228 * * IOCTL commands targeting file descriptions (``FIONBIO``, ``FIOASYNC``), 229 * * IOCTL commands targeting file systems (``FIFREEZE``, ``FITHAW``, 230 * ``FIGETBSZ``, ``FS_IOC_GETFSUUID``, ``FS_IOC_GETFSSYSFSPATH``) 231 * * Some IOCTL commands which do not make sense when used with devices, but 232 * whose implementations are safe and return the right error codes 233 * (``FS_IOC_FIEMAP``, ``FICLONE``, ``FICLONERANGE``, ``FIDEDUPERANGE``) 234 * 235 * This access right is available since the fifth version of the Landlock 236 * ABI. 237 * 238 * .. warning:: 239 * 240 * It is currently not possible to restrict some file-related actions 241 * accessible through these syscall families: :manpage:`chdir(2)`, 242 * :manpage:`stat(2)`, :manpage:`flock(2)`, :manpage:`chmod(2)`, 243 * :manpage:`chown(2)`, :manpage:`setxattr(2)`, :manpage:`utime(2)`, 244 * :manpage:`fcntl(2)`, :manpage:`access(2)`. 245 * Future Landlock evolutions will enable to restrict them. 246 */ 247 /* clang-format off */ 248 #define LANDLOCK_ACCESS_FS_EXECUTE (1ULL << 0) 249 #define LANDLOCK_ACCESS_FS_WRITE_FILE (1ULL << 1) 250 #define LANDLOCK_ACCESS_FS_READ_FILE (1ULL << 2) 251 #define LANDLOCK_ACCESS_FS_READ_DIR (1ULL << 3) 252 #define LANDLOCK_ACCESS_FS_REMOVE_DIR (1ULL << 4) 253 #define LANDLOCK_ACCESS_FS_REMOVE_FILE (1ULL << 5) 254 #define LANDLOCK_ACCESS_FS_MAKE_CHAR (1ULL << 6) 255 #define LANDLOCK_ACCESS_FS_MAKE_DIR (1ULL << 7) 256 #define LANDLOCK_ACCESS_FS_MAKE_REG (1ULL << 8) 257 #define LANDLOCK_ACCESS_FS_MAKE_SOCK (1ULL << 9) 258 #define LANDLOCK_ACCESS_FS_MAKE_FIFO (1ULL << 10) 259 #define LANDLOCK_ACCESS_FS_MAKE_BLOCK (1ULL << 11) 260 #define LANDLOCK_ACCESS_FS_MAKE_SYM (1ULL << 12) 261 #define LANDLOCK_ACCESS_FS_REFER (1ULL << 13) 262 #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) 263 #define LANDLOCK_ACCESS_FS_IOCTL_DEV (1ULL << 15) 264 /* clang-format on */ 265 266 /** 267 * DOC: net_access 268 * 269 * Network flags 270 * ~~~~~~~~~~~~~~~~ 271 * 272 * These flags enable to restrict a sandboxed process to a set of network 273 * actions. 274 * 275 * This is supported since Landlock ABI version 4. 276 * 277 * The following access rights apply to TCP port numbers: 278 * 279 * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. 280 * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to 281 * a remote port. 282 */ 283 /* clang-format off */ 284 #define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) 285 #define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) 286 /* clang-format on */ 287 288 /** 289 * DOC: scope 290 * 291 * Scope flags 292 * ~~~~~~~~~~~ 293 * 294 * These flags enable to isolate a sandboxed process from a set of IPC actions. 295 * Setting a flag for a ruleset will isolate the Landlock domain to forbid 296 * connections to resources outside the domain. 297 * 298 * This is supported since Landlock ABI version 6. 299 * 300 * Scopes: 301 * 302 * - %LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET: Restrict a sandboxed process from 303 * connecting to an abstract UNIX socket created by a process outside the 304 * related Landlock domain (e.g., a parent domain or a non-sandboxed process). 305 * - %LANDLOCK_SCOPE_SIGNAL: Restrict a sandboxed process from sending a signal 306 * to another process outside the domain. 307 */ 308 /* clang-format off */ 309 #define LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET (1ULL << 0) 310 #define LANDLOCK_SCOPE_SIGNAL (1ULL << 1) 311 /* clang-format on*/ 312 313 #endif /* _UAPI_LINUX_LANDLOCK_H */ 314