[RFC PATCH 3/6] landlock: explicitly skip mediation of O_PATH file descriptors

[Ryan Lee <ryan.lee@canonical.com>]

Landlock currently does not have handling of O_PATH fds. Now that they
are being passed to the file_open hook, explicitly skip mediation of
them until we can handle them.

Signed-off-by: Ryan Lee <ryan.lee@canonical.com>
---
 security/landlock/fs.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/security/landlock/fs.c b/security/landlock/fs.c
index 0804f76a67be..37b2167bf4c6 100644
--- a/security/landlock/fs.c
+++ b/security/landlock/fs.c
@@ -1522,6 +1522,14 @@ static int hook_file_open(struct file *const file)
 	if (!dom)
 		return 0;
 
+	/*
+	 * Preserve the behavior of O_PATH fd creation not being mediated, for
+	 * now.  Remove this when the comment below about handling O_PATH fds
+	 * is resolved.
+	 */
+	if (file->f_flags & O_PATH)
+		return 0;
+
 	/*
 	 * Because a file may be opened with O_PATH, get_required_file_open_access()
 	 * may return 0.  This case will be handled with a future Landlock
-- 
2.43.0

base-kernel: v6.14-rc6