Unverified Commit e9c70084 authored by NeilBrown's avatar NeilBrown Committed by Christian Brauner
Browse files

ovl: fail ovl_lock_rename_workdir() if either target is unhashed 



As well as checking that the parent hasn't changed after getting the
lock we need to check that the dentry hasn't been unhashed.
Otherwise we might try to rename something that has been removed.

Reported-by: default avatar <syzbot+bfc9a0ccf0de47d04e8c@syzkaller.appspotmail.com>
Fixes: d2c99558 ("ovl: Call ovl_create_temp() without lock held.")
Signed-off-by: default avatarNeilBrown <neil@brown.name>
Link: https://patch.msgid.link/176429295510.634289.1552337113663461690@noble.neil.brown.name


Tested-by: default avatar <syzbot+bfc9a0ccf0de47d04e8c@syzkaller.appspotmail.com>
Reviewed-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 7b6dcd9b

fs/overlayfs/util.c

+2 −2
Original line number Diff line number Diff line
@@ -1234,9 +1234,9 @@ int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *work, 
		goto err;

	if (trap)

		goto err_unlock;

	if (work && work->d_parent != workdir)

	if (work && (work->d_parent != workdir || d_unhashed(work)))

		goto err_unlock;

	if (upper && upper->d_parent != upperdir)

	if (upper && (upper->d_parent != upperdir || d_unhashed(upper)))

		goto err_unlock;



	return 0;