diff options
Diffstat (limited to 'include/uapi/linux/landlock.h')
| -rw-r--r-- | include/uapi/linux/landlock.h | 36 |
1 files changed, 32 insertions, 4 deletions
diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h index b3d952067f59..9c4bcc37a455 100644 --- a/include/uapi/linux/landlock.h +++ b/include/uapi/linux/landlock.h @@ -21,8 +21,14 @@ 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. This is needed for backward - * compatibility reasons. + * 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; }; @@ -33,7 +39,9 @@ struct landlock_ruleset_attr { * - %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 @@ -60,8 +68,9 @@ struct landlock_path_beneath_attr { */ __u64 allowed_access; /** - * @parent_fd: File descriptor, open with ``O_PATH``, which identifies - * the parent directory of a file hierarchy, or just a file. + * @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; /* @@ -109,6 +118,22 @@ struct landlock_path_beneath_attr { * - %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 also the + * only access right which is always considered handled by any ruleset in + * such a way that reparenting a file hierarchy is always denied by default. + * To avoid privilege escalation, it is not enough to add a rule with this + * access right. When linking or renaming a file, the destination directory + * hierarchy must also always have the same or a superset of restrictions of + * the source hierarchy. If it is not the case, or if the domain doesn't + * handle this access right, such actions are denied by default with errno + * set to ``EXDEV``. Linking also requires a ``LANDLOCK_ACCESS_FS_MAKE_*`` + * access right on the destination directory, and renaming also requires a + * ``LANDLOCK_ACCESS_FS_REMOVE_*`` access right on the source's (file or + * directory) parent. Otherwise, such actions are denied with errno set to + * ``EACCES``. The ``EACCES`` errno prevails over ``EXDEV`` to let user space + * efficiently deal with an unrecoverable error. * * .. warning:: * @@ -120,6 +145,7 @@ struct landlock_path_beneath_attr { * :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) @@ -133,5 +159,7 @@ struct landlock_path_beneath_attr { #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) +/* clang-format on */ #endif /* _UAPI_LINUX_LANDLOCK_H */ |