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virtio_console: Assure used length from device is limited

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[ Upstream commit d00d8da586 ]

The buf->len might come from an untrusted device. This
ensures the value would not exceed the size of the buffer
to avoid data corruption or loss.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210525125622.1203-1-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Xie Yongji 2021-05-25 20:56:22 +08:00 • committed by Greg Kroah-Hartman
commit f6ec306b93
1 changed files with 2 additions and 2 deletions
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4
drivers/char/virtio_console.c
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@ -475,7 +475,7 @@ static struct port_buffer *get_inbuf(struct port *port)
buf = virtqueue_get_buf(port->in_vq, &len);
if (buf) {
buf->len = len;
buf->len = min_t(size_t, len, buf->size);
buf->offset = 0;
port->stats.bytes_received += len;
}
@ -1712,7 +1712,7 @@ static void control_work_handler(struct work_struct *work)
while ((buf = virtqueue_get_buf(vq, &len))) {
spin_unlock(&portdev->c_ivq_lock);
buf->len = len;
buf->len = min_t(size_t, len, buf->size);
buf->offset = 0;
handle_control_message(vq->vdev, portdev, buf);