Re: [PATCH net-next v3 2/2] net: qualcomm: rmnet: Fix rx_handler for non-linear skbs

On Wed, 3 Feb 2021 at 15:04, Willem de Bruijn
[off-list ref] wrote:

On Wed, Feb 3, 2021 at 8:17 AM Loic Poulain [off-list ref] wrote:

quoted

There is no guarantee that rmnet rx_handler is only fed with linear
skbs, but current rmnet implementation does not check that, leading
to crash in case of non linear skbs processed as linear ones.

Fix that by ensuring skb linearization before processing.

Signed-off-by: Loic Poulain <redacted>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Subash Abhinov Kasiviswanathan <redacted>
---
 v2: Add this patch to the series to prevent crash
 v3: no change

 drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
index 3d7d3ab..2776c32 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c

@@ -180,7 +180,7 @@ rx_handler_result_t rmnet_rx_handler(struct sk_buff **pskb)
        struct rmnet_port *port;
        struct net_device *dev;

-       if (!skb)
+       if (!skb || skb_linearize(skb))
                goto done;

Actually, if skb_linearize fails, the skb must be freed.

Ouch, you're right.

Regards,
Loic