landlock.h (11707B) - Raw
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 _LINUX_LANDLOCK_H 10 #define _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 */ 61 /* clang-format off */ 62 #define LANDLOCK_CREATE_RULESET_VERSION (1U << 0) 63 /* clang-format on */ 64 65 /** 66 * enum landlock_rule_type - Landlock rule type 67 * 68 * Argument of sys_landlock_add_rule(). 69 */ 70 enum landlock_rule_type { 71 /** 72 * @LANDLOCK_RULE_PATH_BENEATH: Type of a &struct 73 * landlock_path_beneath_attr . 74 */ 75 LANDLOCK_RULE_PATH_BENEATH = 1, 76 /** 77 * @LANDLOCK_RULE_NET_PORT: Type of a &struct 78 * landlock_net_port_attr . 79 */ 80 LANDLOCK_RULE_NET_PORT, 81 }; 82 83 /** 84 * struct landlock_path_beneath_attr - Path hierarchy definition 85 * 86 * Argument of sys_landlock_add_rule(). 87 */ 88 struct landlock_path_beneath_attr { 89 /** 90 * @allowed_access: Bitmask of allowed actions for this file hierarchy 91 * (cf. `Filesystem flags`_). 92 */ 93 __u64 allowed_access; 94 /** 95 * @parent_fd: File descriptor, preferably opened with ``O_PATH``, 96 * which identifies the parent directory of a file hierarchy, or just a 97 * file. 98 */ 99 __s32 parent_fd; 100 /* 101 * This struct is packed to avoid trailing reserved members. 102 * Cf. security/landlock/syscalls.c:build_check_abi() 103 */ 104 } __attribute__((packed)); 105 106 /** 107 * struct landlock_net_port_attr - Network port definition 108 * 109 * Argument of sys_landlock_add_rule(). 110 */ 111 struct landlock_net_port_attr { 112 /** 113 * @allowed_access: Bitmask of allowed network actions for a port 114 * (cf. `Network flags`_). 115 */ 116 __u64 allowed_access; 117 /** 118 * @port: Network port in host endianness. 119 * 120 * It should be noted that port 0 passed to :manpage:`bind(2)` will bind 121 * to an available port from the ephemeral port range. This can be 122 * configured with the ``/proc/sys/net/ipv4/ip_local_port_range`` sysctl 123 * (also used for IPv6). 124 * 125 * A Landlock rule with port 0 and the ``LANDLOCK_ACCESS_NET_BIND_TCP`` 126 * right means that requesting to bind on port 0 is allowed and it will 127 * automatically translate to binding on the related port range. 128 */ 129 __u64 port; 130 }; 131 132 /** 133 * DOC: fs_access 134 * 135 * A set of actions on kernel objects may be defined by an attribute (e.g. 136 * &struct landlock_path_beneath_attr) including a bitmask of access. 137 * 138 * Filesystem flags 139 * ~~~~~~~~~~~~~~~~ 140 * 141 * These flags enable to restrict a sandboxed process to a set of actions on 142 * files and directories. Files or directories opened before the sandboxing 143 * are not subject to these restrictions. 144 * 145 * The following access rights apply only to files: 146 * 147 * - %LANDLOCK_ACCESS_FS_EXECUTE: Execute a file. 148 * - %LANDLOCK_ACCESS_FS_WRITE_FILE: Open a file with write access. When 149 * opening files for writing, you will often additionally need the 150 * %LANDLOCK_ACCESS_FS_TRUNCATE right. In many cases, these system calls 151 * truncate existing files when overwriting them (e.g., :manpage:`creat(2)`). 152 * - %LANDLOCK_ACCESS_FS_READ_FILE: Open a file with read access. 153 * - %LANDLOCK_ACCESS_FS_TRUNCATE: Truncate a file with :manpage:`truncate(2)`, 154 * :manpage:`ftruncate(2)`, :manpage:`creat(2)`, or :manpage:`open(2)` with 155 * ``O_TRUNC``. This access right is available since the third version of the 156 * Landlock ABI. 157 * 158 * Whether an opened file can be truncated with :manpage:`ftruncate(2)` or used 159 * with `ioctl(2)` is determined during :manpage:`open(2)`, in the same way as 160 * read and write permissions are checked during :manpage:`open(2)` using 161 * %LANDLOCK_ACCESS_FS_READ_FILE and %LANDLOCK_ACCESS_FS_WRITE_FILE. 162 * 163 * A directory can receive access rights related to files or directories. The 164 * following access right is applied to the directory itself, and the 165 * directories beneath it: 166 * 167 * - %LANDLOCK_ACCESS_FS_READ_DIR: Open a directory or list its content. 168 * 169 * However, the following access rights only apply to the content of a 170 * directory, not the directory itself: 171 * 172 * - %LANDLOCK_ACCESS_FS_REMOVE_DIR: Remove an empty directory or rename one. 173 * - %LANDLOCK_ACCESS_FS_REMOVE_FILE: Unlink (or rename) a file. 174 * - %LANDLOCK_ACCESS_FS_MAKE_CHAR: Create (or rename or link) a character 175 * device. 176 * - %LANDLOCK_ACCESS_FS_MAKE_DIR: Create (or rename) a directory. 177 * - %LANDLOCK_ACCESS_FS_MAKE_REG: Create (or rename or link) a regular file. 178 * - %LANDLOCK_ACCESS_FS_MAKE_SOCK: Create (or rename or link) a UNIX domain 179 * socket. 180 * - %LANDLOCK_ACCESS_FS_MAKE_FIFO: Create (or rename or link) a named pipe. 181 * - %LANDLOCK_ACCESS_FS_MAKE_BLOCK: Create (or rename or link) a block device. 182 * - %LANDLOCK_ACCESS_FS_MAKE_SYM: Create (or rename or link) a symbolic link. 183 * - %LANDLOCK_ACCESS_FS_REFER: Link or rename a file from or to a different 184 * directory (i.e. reparent a file hierarchy). 185 * 186 * This access right is available since the second version of the Landlock 187 * ABI. 188 * 189 * This is the only access right which is denied by default by any ruleset, 190 * even if the right is not specified as handled at ruleset creation time. 191 * The only way to make a ruleset grant this right is to explicitly allow it 192 * for a specific directory by adding a matching rule to the ruleset. 193 * 194 * In particular, when using the first Landlock ABI version, Landlock will 195 * always deny attempts to reparent files between different directories. 196 * 197 * In addition to the source and destination directories having the 198 * %LANDLOCK_ACCESS_FS_REFER access right, the attempted link or rename 199 * operation must meet the following constraints: 200 * 201 * * The reparented file may not gain more access rights in the destination 202 * directory than it previously had in the source directory. If this is 203 * attempted, the operation results in an ``EXDEV`` error. 204 * 205 * * When linking or renaming, the ``LANDLOCK_ACCESS_FS_MAKE_*`` right for the 206 * respective file type must be granted for the destination directory. 207 * Otherwise, the operation results in an ``EACCES`` error. 208 * 209 * * When renaming, the ``LANDLOCK_ACCESS_FS_REMOVE_*`` right for the 210 * respective file type must be granted for the source directory. Otherwise, 211 * the operation results in an ``EACCES`` error. 212 * 213 * If multiple requirements are not met, the ``EACCES`` error code takes 214 * precedence over ``EXDEV``. 215 * 216 * The following access right applies both to files and directories: 217 * 218 * - %LANDLOCK_ACCESS_FS_IOCTL_DEV: Invoke :manpage:`ioctl(2)` commands on an opened 219 * character or block device. 220 * 221 * This access right applies to all `ioctl(2)` commands implemented by device 222 * drivers. However, the following common IOCTL commands continue to be 223 * invokable independent of the %LANDLOCK_ACCESS_FS_IOCTL_DEV right: 224 * 225 * * IOCTL commands targeting file descriptors (``FIOCLEX``, ``FIONCLEX``), 226 * * IOCTL commands targeting file descriptions (``FIONBIO``, ``FIOASYNC``), 227 * * IOCTL commands targeting file systems (``FIFREEZE``, ``FITHAW``, 228 * ``FIGETBSZ``, ``FS_IOC_GETFSUUID``, ``FS_IOC_GETFSSYSFSPATH``) 229 * * Some IOCTL commands which do not make sense when used with devices, but 230 * whose implementations are safe and return the right error codes 231 * (``FS_IOC_FIEMAP``, ``FICLONE``, ``FICLONERANGE``, ``FIDEDUPERANGE``) 232 * 233 * This access right is available since the fifth version of the Landlock 234 * ABI. 235 * 236 * .. warning:: 237 * 238 * It is currently not possible to restrict some file-related actions 239 * accessible through these syscall families: :manpage:`chdir(2)`, 240 * :manpage:`stat(2)`, :manpage:`flock(2)`, :manpage:`chmod(2)`, 241 * :manpage:`chown(2)`, :manpage:`setxattr(2)`, :manpage:`utime(2)`, 242 * :manpage:`fcntl(2)`, :manpage:`access(2)`. 243 * Future Landlock evolutions will enable to restrict them. 244 */ 245 /* clang-format off */ 246 #define LANDLOCK_ACCESS_FS_EXECUTE (1ULL << 0) 247 #define LANDLOCK_ACCESS_FS_WRITE_FILE (1ULL << 1) 248 #define LANDLOCK_ACCESS_FS_READ_FILE (1ULL << 2) 249 #define LANDLOCK_ACCESS_FS_READ_DIR (1ULL << 3) 250 #define LANDLOCK_ACCESS_FS_REMOVE_DIR (1ULL << 4) 251 #define LANDLOCK_ACCESS_FS_REMOVE_FILE (1ULL << 5) 252 #define LANDLOCK_ACCESS_FS_MAKE_CHAR (1ULL << 6) 253 #define LANDLOCK_ACCESS_FS_MAKE_DIR (1ULL << 7) 254 #define LANDLOCK_ACCESS_FS_MAKE_REG (1ULL << 8) 255 #define LANDLOCK_ACCESS_FS_MAKE_SOCK (1ULL << 9) 256 #define LANDLOCK_ACCESS_FS_MAKE_FIFO (1ULL << 10) 257 #define LANDLOCK_ACCESS_FS_MAKE_BLOCK (1ULL << 11) 258 #define LANDLOCK_ACCESS_FS_MAKE_SYM (1ULL << 12) 259 #define LANDLOCK_ACCESS_FS_REFER (1ULL << 13) 260 #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) 261 #define LANDLOCK_ACCESS_FS_IOCTL_DEV (1ULL << 15) 262 /* clang-format on */ 263 264 /** 265 * DOC: net_access 266 * 267 * Network flags 268 * ~~~~~~~~~~~~~~~~ 269 * 270 * These flags enable to restrict a sandboxed process to a set of network 271 * actions. This is supported since the Landlock ABI version 4. 272 * 273 * The following access rights apply to TCP port numbers: 274 * 275 * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. 276 * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to 277 * a remote port. 278 */ 279 /* clang-format off */ 280 #define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) 281 #define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) 282 /* clang-format on */ 283 284 /** 285 * DOC: scope 286 * 287 * Scope flags 288 * ~~~~~~~~~~~ 289 * 290 * These flags enable to isolate a sandboxed process from a set of IPC actions. 291 * Setting a flag for a ruleset will isolate the Landlock domain to forbid 292 * connections to resources outside the domain. 293 * 294 * Scopes: 295 * 296 * - %LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET: Restrict a sandboxed process from 297 * connecting to an abstract UNIX socket created by a process outside the 298 * related Landlock domain (e.g. a parent domain or a non-sandboxed process). 299 * - %LANDLOCK_SCOPE_SIGNAL: Restrict a sandboxed process from sending a signal 300 * to another process outside the domain. 301 */ 302 /* clang-format off */ 303 #define LANDLOCK_SCOPE_ABSTRACT_UNIX_SOCKET (1ULL << 0) 304 #define LANDLOCK_SCOPE_SIGNAL (1ULL << 1) 305 /* clang-format on*/ 306 307 #endif /* _LINUX_LANDLOCK_H */