diff options
| author | Eryu Guan <eguan@redhat.com> | 2018-01-24 01:20:00 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-26 11:02:11 +0200 |
| commit | f25ba4f6be4aa368a4ce22d225d4c09257b3667a (patch) | |
| tree | 0bf6b46078fa769be4c16fe2ca582eaaa5b6b7a6 /block | |
| parent | a42ebbdae0a58e62906a47fc36b89822c82f627a (diff) | |
blk-mq-debugfs: don't allow write on attributes with seq_operations set
[ Upstream commit 6b136a24b05c81a24e0b648a4bd938bcd0c4f69e ]
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: Eryu Guan <eguan@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq-debugfs.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index de294d775acf..d95439154556 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -704,7 +704,11 @@ 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); |