Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6b136a24 authored by Eryu Guan's avatar Eryu Guan Committed by Jens Axboe
Browse files

blk-mq-debugfs: don't allow write on attributes with seq_operations set 



Attributes that only implement .seq_ops are read-only, any write to
them should be rejected. But currently kernel would crash when
writing to such debugfs entries, e.g.

chmod +w /sys/kernel/debug/block/<dev>/requeue_list
echo 0 > /sys/kernel/debug/block/<dev>/requeue_list
chmod -w /sys/kernel/debug/block/<dev>/requeue_list

Fix it by returning -EPERM in blk_mq_debugfs_write() when writing to
such attributes.

Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: default avatarEryu Guan <eguan@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 20d59023

block/blk-mq-debugfs.c

+5 −1
Original line number Diff line number Diff line
@@ -697,7 +697,11 @@ static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf, 
	const struct blk_mq_debugfs_attr *attr = m->private;

	void *data = d_inode(file->f_path.dentry->d_parent)->i_private;



	if (!attr->write)

	/*

	 * Attributes that only implement .seq_ops are read-only and 'attr' is

	 * the same with 'data' in this case.

	 */

	if (attr == data || !attr->write)

		return -EPERM;



	return attr->write(data, buf, count, ppos);