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