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Diffstat (limited to 'include/uapi/linux/landlock.h')
-rw-r--r--include/uapi/linux/landlock.h21
1 files changed, 16 insertions, 5 deletions
diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h
index 9c4bcc37a455..f3223f964691 100644
--- a/include/uapi/linux/landlock.h
+++ b/include/uapi/linux/landlock.h
@@ -95,8 +95,19 @@ struct landlock_path_beneath_attr {
* 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.
+ * - %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
@@ -139,10 +150,9 @@ struct landlock_path_beneath_attr {
*
* It is currently not possible to restrict some file-related actions
* accessible through these syscall families: :manpage:`chdir(2)`,
- * :manpage:`truncate(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)`.
+ * :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 */
@@ -160,6 +170,7 @@ struct landlock_path_beneath_attr {
#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 /* _UAPI_LINUX_LANDLOCK_H */