diff options
| author | Eryu Guan <eguan@redhat.com> | 2018-01-24 01:20:00 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-01-24 09:46:09 -0700 |
| commit | 6b136a24b05c81a24e0b648a4bd938bcd0c4f69e (patch) | |
| tree | efa76cb522a4a75c2970b6ec0a59aa64ba391706 | |
| parent | 20d59023c5ec4426284af492808bcea1f39787ef (diff) | |
| download | linux-6b136a24b05c81a24e0b648a4bd938bcd0c4f69e.tar.bz2 | |
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: Eryu Guan <eguan@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -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 fa31ceaa8de6..21cbc1f071c6 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -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); |