[PATCH AUTOSEL 5.4 27/28] virtio_console: Assure used length from device is limited
From: Sasha Levin <sashal@kernel.org>
Date: 2021-07-10 23:54:07
Also in:
lkml, virtualization
Subsystem:
char and misc drivers, the rest, virtio console driver · Maintainers:
Arnd Bergmann, Greg Kroah-Hartman, Linus Torvalds, Amit Shah
From: Xie Yongji <redacted> [ Upstream commit d00d8da5869a2608e97cfede094dfc5e11462a46 ] 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 <redacted> Acked-by: Jason Wang <jasowang@redhat.com> Link: https://lore.kernel.org/r/20210525125622.1203-1-xieyongji@bytedance.com (local) Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/char/virtio_console.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 5eabbf73fdef..b453029487a1 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c@@ -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; }
@@ -1714,7 +1714,7 @@ 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);
--
2.30.2