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/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
* Landlock - User space API
*
* Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
* Copyright © 2018-2020 ANSSI
*/
#ifndef _LINUX_LANDLOCK_H
#define _LINUX_LANDLOCK_H
#include <linux/types.h>
/**
* struct landlock_ruleset_attr - Ruleset definition
*
* Argument of sys_landlock_create_ruleset(). This structure can grow in
* future versions.
*/
struct landlock_ruleset_attr {
/**
* @handled_access_fs: Bitmask of actions (cf. `Filesystem flags`_)
* that is handled by this ruleset and should then be forbidden if no
* rule explicitly allow them: it is a deny-by-default list that should
* contain as much Landlock access rights as possible. Indeed, all
* Landlock filesystem access rights that are not part of
* handled_access_fs are allowed. This is needed for backward
* compatibility reasons. One exception is the
* %LANDLOCK_ACCESS_FS_REFER access right, which is always implicitly
* handled, but must still be explicitly handled to add new rules with
* this access right.
*/
__u64 handled_access_fs;
};
/*
* sys_landlock_create_ruleset() flags:
*
* - %LANDLOCK_CREATE_RULESET_VERSION: Get the highest supported Landlock ABI
* version.
*/
/* clang-format off */
#define LANDLOCK_CREATE_RULESET_VERSION (1U << 0)
/* clang-format on */
/**
* enum landlock_rule_type - Landlock rule type
*
* Argument of sys_landlock_add_rule().
*/
enum landlock_rule_type {
/**
* @LANDLOCK_RULE_PATH_BENEATH: Type of a &struct
* landlock_path_beneath_attr .
*/
LANDLOCK_RULE_PATH_BENEATH = 1,
};
/**
* struct landlock_path_beneath_attr - Path hierarchy definition
*
* Argument of sys_landlock_add_rule().
*/
struct landlock_path_beneath_attr {
/**
* @allowed_access: Bitmask of allowed actions for this file hierarchy
* (cf. `Filesystem flags`_).
*/
__u64 allowed_access;
/**
* @parent_fd: File descriptor, preferably opened with ``O_PATH``,
* which identifies the parent directory of a file hierarchy, or just a
* file.
*/
__s32 parent_fd;
/*
* This struct is packed to avoid trailing reserved members.
* Cf. security/landlock/syscalls.c:build_check_abi()
*/
} __attribute__((packed));
/**
* DOC: fs_access
*
* A set of actions on kernel objects may be defined by an attribute (e.g.
* &struct landlock_path_beneath_attr) including a bitmask of access.
*
* Filesystem flags
* ~~~~~~~~~~~~~~~~
*
* These flags enable to restrict a sandboxed process to a set of actions on
* files and directories. Files or directories opened before the sandboxing
* are not subject to these restrictions.
*
* A file can only receive these access rights:
*
* - %LANDLOCK_ACCESS_FS_EXECUTE: Execute a file.
* - %LANDLOCK_ACCESS_FS_WRITE_FILE: Open a file with write access. Note that
* you might additionally need the %LANDLOCK_ACCESS_FS_TRUNCATE right in order
* to overwrite files with :manpage:`open(2)` using ``O_TRUNC`` or
* :manpage:`creat(2)`.
* - %LANDLOCK_ACCESS_FS_READ_FILE: Open a file with read access.
* - %LANDLOCK_ACCESS_FS_TRUNCATE: Truncate a file with :manpage:`truncate(2)`,
* :manpage:`ftruncate(2)`, :manpage:`creat(2)`, or :manpage:`open(2)` with
* ``O_TRUNC``. Whether an opened file can be truncated with
* :manpage:`ftruncate(2)` is determined during :manpage:`open(2)`, in the
* same way as read and write permissions are checked during
* :manpage:`open(2)` using %LANDLOCK_ACCESS_FS_READ_FILE and
* %LANDLOCK_ACCESS_FS_WRITE_FILE. This access right is available since the
* third version of the Landlock ABI.
*
* A directory can receive access rights related to files or directories. The
* following access right is applied to the directory itself, and the
* directories beneath it:
*
* - %LANDLOCK_ACCESS_FS_READ_DIR: Open a directory or list its content.
*
* However, the following access rights only apply to the content of a
* directory, not the directory itself:
*
* - %LANDLOCK_ACCESS_FS_REMOVE_DIR: Remove an empty directory or rename one.
* - %LANDLOCK_ACCESS_FS_REMOVE_FILE: Unlink (or rename) a file.
* - %LANDLOCK_ACCESS_FS_MAKE_CHAR: Create (or rename or link) a character
* device.
* - %LANDLOCK_ACCESS_FS_MAKE_DIR: Create (or rename) a directory.
* - %LANDLOCK_ACCESS_FS_MAKE_REG: Create (or rename or link) a regular file.
* - %LANDLOCK_ACCESS_FS_MAKE_SOCK: Create (or rename or link) a UNIX domain
* socket.
* - %LANDLOCK_ACCESS_FS_MAKE_FIFO: Create (or rename or link) a named pipe.
* - %LANDLOCK_ACCESS_FS_MAKE_BLOCK: Create (or rename or link) a block device.
* - %LANDLOCK_ACCESS_FS_MAKE_SYM: Create (or rename or link) a symbolic link.
* - %LANDLOCK_ACCESS_FS_REFER: Link or rename a file from or to a different
* directory (i.e. reparent a file hierarchy).
*
* This access right is available since the second version of the Landlock
* ABI.
*
* This is the only access right which is denied by default by any ruleset,
* even if the right is not specified as handled at ruleset creation time.
* The only way to make a ruleset grant this right is to explicitly allow it
* for a specific directory by adding a matching rule to the ruleset.
*
* In particular, when using the first Landlock ABI version, Landlock will
* always deny attempts to reparent files between different directories.
*
* In addition to the source and destination directories having the
* %LANDLOCK_ACCESS_FS_REFER access right, the attempted link or rename
* operation must meet the following constraints:
*
* * The reparented file may not gain more access rights in the destination
* directory than it previously had in the source directory. If this is
* attempted, the operation results in an ``EXDEV`` error.
*
* * When linking or renaming, the ``LANDLOCK_ACCESS_FS_MAKE_*`` right for the
* respective file type must be granted for the destination directory.
* Otherwise, the operation results in an ``EACCES`` error.
*
* * When renaming, the ``LANDLOCK_ACCESS_FS_REMOVE_*`` right for the
* respective file type must be granted for the source directory. Otherwise,
* the operation results in an ``EACCES`` error.
*
* If multiple requirements are not met, the ``EACCES`` error code takes
* precedence over ``EXDEV``.
*
* .. warning::
*
* It is currently not possible to restrict some file-related actions
* accessible through these syscall families: :manpage:`chdir(2)`,
* :manpage:`stat(2)`, :manpage:`flock(2)`, :manpage:`chmod(2)`,
* :manpage:`chown(2)`, :manpage:`setxattr(2)`, :manpage:`utime(2)`,
* :manpage:`ioctl(2)`, :manpage:`fcntl(2)`, :manpage:`access(2)`.
* Future Landlock evolutions will enable to restrict them.
*/
/* clang-format off */
#define LANDLOCK_ACCESS_FS_EXECUTE (1ULL << 0)
#define LANDLOCK_ACCESS_FS_WRITE_FILE (1ULL << 1)
#define LANDLOCK_ACCESS_FS_READ_FILE (1ULL << 2)
#define LANDLOCK_ACCESS_FS_READ_DIR (1ULL << 3)
#define LANDLOCK_ACCESS_FS_REMOVE_DIR (1ULL << 4)
#define LANDLOCK_ACCESS_FS_REMOVE_FILE (1ULL << 5)
#define LANDLOCK_ACCESS_FS_MAKE_CHAR (1ULL << 6)
#define LANDLOCK_ACCESS_FS_MAKE_DIR (1ULL << 7)
#define LANDLOCK_ACCESS_FS_MAKE_REG (1ULL << 8)
#define LANDLOCK_ACCESS_FS_MAKE_SOCK (1ULL << 9)
#define LANDLOCK_ACCESS_FS_MAKE_FIFO (1ULL << 10)
#define LANDLOCK_ACCESS_FS_MAKE_BLOCK (1ULL << 11)
#define LANDLOCK_ACCESS_FS_MAKE_SYM (1ULL << 12)
#define LANDLOCK_ACCESS_FS_REFER (1ULL << 13)
#define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14)
/* clang-format on */
#endif /* _LINUX_LANDLOCK_H */
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