net: calxedaxgmac: throw away overrun frames

[ Upstream commit d6fb3be544b46a7611a3373fcaa62b5b0be01888 ]

The xgmac driver assumes 1 frame per descriptor. If a frame larger than
the descriptor's buffer size is received, the frame will spill over into
the next descriptor. So check for received frames that span more than one
descriptor and discard them. This prevents a crash if we receive erroneous
large packets.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Cc: netdev@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c
index 11f667f6131abf97c34faf9f5bac9dec887f17f3..4ebbe6f609d0b90a4464cc41094be77b0ad373b8 100644 (file)
--- a/drivers/net/ethernet/calxeda/xgmac.c
+++ b/drivers/net/ethernet/calxeda/xgmac.c
@@ -547,6 +547,10 @@ static int desc_get_rx_status(struct xgmac_priv *priv, struct xgmac_dma_desc *p)
                return -1;
        }
 
+       /* All frames should fit into a single buffer */
+       if (!(status & RXDESC_FIRST_SEG) || !(status & RXDESC_LAST_SEG))
+               return -1;
+
        /* Check if packet has checksum already */
        if ((status & RXDESC_FRAME_TYPE) && (status & RXDESC_EXT_STATUS) &&
                !(ext_status & RXDESC_IP_PAYLOAD_MASK))