From: Xie Yongji <[email protected]>

[ 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 <[email protected]>
Acked-by: Jason Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 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 1836cc56e357..673522874cec 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;
        }
@@ -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);
-- 
2.30.2

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