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 _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(). This structure can grow in 18 * future versions. 19 */ 20 struct landlock_ruleset_attr { 21 /** 22 * @handled_access_fs: Bitmask of actions (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. 32 */ 33 __u64 handled_access_fs; 34 /** 35 * @handled_access_net: Bitmask of actions (cf. `Network flags`_) 36 * that is handled by this ruleset and should then be forbidden if no 37 * rule explicitly allow them. 38 */ 39 __u64 handled_access_net; 40 }; 41 42 /* 43 * sys_landlock_create_ruleset() flags: 44 * 45 * - %LANDLOCK_CREATE_RULESET_VERSION: Get the highest supported Landlock ABI 46 * version. 47 */ 48 /* clang-format off */ 49 #define LANDLOCK_CREATE_RULESET_VERSION (1U << 0) 50 /* clang-format on */ 51 52 /** 53 * enum landlock_rule_type - Landlock rule type 54 * 55 * Argument of sys_landlock_add_rule(). 56 */ 57 enum landlock_rule_type { 58 /** 59 * @LANDLOCK_RULE_PATH_BENEATH: Type of a &struct 60 * landlock_path_beneath_attr . 61 */ 62 LANDLOCK_RULE_PATH_BENEATH = 1, 63 /** 64 * @LANDLOCK_RULE_NET_PORT: Type of a &struct 65 * landlock_net_port_attr . 66 */ 67 LANDLOCK_RULE_NET_PORT, 68 }; 69 70 /** 71 * struct landlock_path_beneath_attr - Path hierarchy definition 72 * 73 * Argument of sys_landlock_add_rule(). 74 */ 75 struct landlock_path_beneath_attr { 76 /** 77 * @allowed_access: Bitmask of allowed actions for this file hierarchy 78 * (cf. `Filesystem flags`_). 79 */ 80 __u64 allowed_access; 81 /** 82 * @parent_fd: File descriptor, preferably opened with ``O_PATH``, 83 * which identifies the parent directory of a file hierarchy, or just a 84 * file. 85 */ 86 __s32 parent_fd; 87 /* 88 * This struct is packed to avoid trailing reserved members. 89 * Cf. security/landlock/syscalls.c:build_check_abi() 90 */ 91 } __attribute__((packed)); 92 93 /** 94 * struct landlock_net_port_attr - Network port definition 95 * 96 * Argument of sys_landlock_add_rule(). 97 */ 98 struct landlock_net_port_attr { 99 /** 100 * @allowed_access: Bitmask of allowed access network for a port 101 * (cf. `Network flags`_). 102 */ 103 __u64 allowed_access; 104 /** 105 * @port: Network port in host endianness. 106 * 107 * It should be noted that port 0 passed to :manpage:`bind(2)` will 108 * bind to an available port from a specific port range. This can be 109 * configured thanks to the ``/proc/sys/net/ipv4/ip_local_port_range`` 110 * sysctl (also used for IPv6). A Landlock rule with port 0 and the 111 * ``LANDLOCK_ACCESS_NET_BIND_TCP`` right means that requesting to bind 112 * on port 0 is allowed and it will automatically translate to binding 113 * on the related port range. 114 */ 115 __u64 port; 116 }; 117 118 /** 119 * DOC: fs_access 120 * 121 * A set of actions on kernel objects may be defined by an attribute (e.g. 122 * &struct landlock_path_beneath_attr) including a bitmask of access. 123 * 124 * Filesystem flags 125 * ~~~~~~~~~~~~~~~~ 126 * 127 * These flags enable to restrict a sandboxed process to a set of actions on 128 * files and directories. Files or directories opened before the sandboxing 129 * are not subject to these restrictions. 130 * 131 * A file can only receive these access rights: 132 * 133 * - %LANDLOCK_ACCESS_FS_EXECUTE: Execute a file. 134 * - %LANDLOCK_ACCESS_FS_WRITE_FILE: Open a file with write access. Note that 135 * you might additionally need the %LANDLOCK_ACCESS_FS_TRUNCATE right in order 136 * to overwrite files with :manpage:`open(2)` using ``O_TRUNC`` or 137 * :manpage:`creat(2)`. 138 * - %LANDLOCK_ACCESS_FS_READ_FILE: Open a file with read access. 139 * - %LANDLOCK_ACCESS_FS_TRUNCATE: Truncate a file with :manpage:`truncate(2)`, 140 * :manpage:`ftruncate(2)`, :manpage:`creat(2)`, or :manpage:`open(2)` with 141 * ``O_TRUNC``. Whether an opened file can be truncated with 142 * :manpage:`ftruncate(2)` is determined during :manpage:`open(2)`, in the 143 * same way as read and write permissions are checked during 144 * :manpage:`open(2)` using %LANDLOCK_ACCESS_FS_READ_FILE and 145 * %LANDLOCK_ACCESS_FS_WRITE_FILE. This access right is available since the 146 * third version of the Landlock ABI. 147 * 148 * A directory can receive access rights related to files or directories. The 149 * following access right is applied to the directory itself, and the 150 * directories beneath it: 151 * 152 * - %LANDLOCK_ACCESS_FS_READ_DIR: Open a directory or list its content. 153 * 154 * However, the following access rights only apply to the content of a 155 * directory, not the directory itself: 156 * 157 * - %LANDLOCK_ACCESS_FS_REMOVE_DIR: Remove an empty directory or rename one. 158 * - %LANDLOCK_ACCESS_FS_REMOVE_FILE: Unlink (or rename) a file. 159 * - %LANDLOCK_ACCESS_FS_MAKE_CHAR: Create (or rename or link) a character 160 * device. 161 * - %LANDLOCK_ACCESS_FS_MAKE_DIR: Create (or rename) a directory. 162 * - %LANDLOCK_ACCESS_FS_MAKE_REG: Create (or rename or link) a regular file. 163 * - %LANDLOCK_ACCESS_FS_MAKE_SOCK: Create (or rename or link) a UNIX domain 164 * socket. 165 * - %LANDLOCK_ACCESS_FS_MAKE_FIFO: Create (or rename or link) a named pipe. 166 * - %LANDLOCK_ACCESS_FS_MAKE_BLOCK: Create (or rename or link) a block device. 167 * - %LANDLOCK_ACCESS_FS_MAKE_SYM: Create (or rename or link) a symbolic link. 168 * - %LANDLOCK_ACCESS_FS_REFER: Link or rename a file from or to a different 169 * directory (i.e. reparent a file hierarchy). 170 * 171 * This access right is available since the second version of the Landlock 172 * ABI. 173 * 174 * This is the only access right which is denied by default by any ruleset, 175 * even if the right is not specified as handled at ruleset creation time. 176 * The only way to make a ruleset grant this right is to explicitly allow it 177 * for a specific directory by adding a matching rule to the ruleset. 178 * 179 * In particular, when using the first Landlock ABI version, Landlock will 180 * always deny attempts to reparent files between different directories. 181 * 182 * In addition to the source and destination directories having the 183 * %LANDLOCK_ACCESS_FS_REFER access right, the attempted link or rename 184 * operation must meet the following constraints: 185 * 186 * * The reparented file may not gain more access rights in the destination 187 * directory than it previously had in the source directory. If this is 188 * attempted, the operation results in an ``EXDEV`` error. 189 * 190 * * When linking or renaming, the ``LANDLOCK_ACCESS_FS_MAKE_*`` right for the 191 * respective file type must be granted for the destination directory. 192 * Otherwise, the operation results in an ``EACCES`` error. 193 * 194 * * When renaming, the ``LANDLOCK_ACCESS_FS_REMOVE_*`` right for the 195 * respective file type must be granted for the source directory. Otherwise, 196 * the operation results in an ``EACCES`` error. 197 * 198 * If multiple requirements are not met, the ``EACCES`` error code takes 199 * precedence over ``EXDEV``. 200 * 201 * .. warning:: 202 * 203 * It is currently not possible to restrict some file-related actions 204 * accessible through these syscall families: :manpage:`chdir(2)`, 205 * :manpage:`stat(2)`, :manpage:`flock(2)`, :manpage:`chmod(2)`, 206 * :manpage:`chown(2)`, :manpage:`setxattr(2)`, :manpage:`utime(2)`, 207 * :manpage:`ioctl(2)`, :manpage:`fcntl(2)`, :manpage:`access(2)`. 208 * Future Landlock evolutions will enable to restrict them. 209 */ 210 /* clang-format off */ 211 #define LANDLOCK_ACCESS_FS_EXECUTE (1ULL << 0) 212 #define LANDLOCK_ACCESS_FS_WRITE_FILE (1ULL << 1) 213 #define LANDLOCK_ACCESS_FS_READ_FILE (1ULL << 2) 214 #define LANDLOCK_ACCESS_FS_READ_DIR (1ULL << 3) 215 #define LANDLOCK_ACCESS_FS_REMOVE_DIR (1ULL << 4) 216 #define LANDLOCK_ACCESS_FS_REMOVE_FILE (1ULL << 5) 217 #define LANDLOCK_ACCESS_FS_MAKE_CHAR (1ULL << 6) 218 #define LANDLOCK_ACCESS_FS_MAKE_DIR (1ULL << 7) 219 #define LANDLOCK_ACCESS_FS_MAKE_REG (1ULL << 8) 220 #define LANDLOCK_ACCESS_FS_MAKE_SOCK (1ULL << 9) 221 #define LANDLOCK_ACCESS_FS_MAKE_FIFO (1ULL << 10) 222 #define LANDLOCK_ACCESS_FS_MAKE_BLOCK (1ULL << 11) 223 #define LANDLOCK_ACCESS_FS_MAKE_SYM (1ULL << 12) 224 #define LANDLOCK_ACCESS_FS_REFER (1ULL << 13) 225 #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) 226 /* clang-format on */ 227 228 /** 229 * DOC: net_access 230 * 231 * Network flags 232 * ~~~~~~~~~~~~~~~~ 233 * 234 * These flags enable to restrict a sandboxed process to a set of network 235 * actions. This is supported since the Landlock ABI version 4. 236 * 237 * TCP sockets with allowed actions: 238 * 239 * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. 240 * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to 241 * a remote port. 242 */ 243 /* clang-format off */ 244 #define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) 245 #define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) 246 /* clang-format on */ 247 #endif /* _UAPI_LINUX_LANDLOCK_H */ 248