include/uapi/linux/landlock.h

   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().
  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 /* _UAPI_LINUX_LANDLOCK_H */