net: calxedaxgmac: throw away overrun frames

Submitted by Rob Herring on Jan. 16, 2013, 11:36 p.m.

Details

Message ID 1358379397-7152-1-git-send-email-robherring2@gmail.com
State Accepted
Delegated to: David Miller
Headers show

Commit Message

Rob Herring Jan. 16, 2013, 11:36 p.m.
From: Rob Herring <rob.herring@calxeda.com>

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
---
 drivers/net/ethernet/calxeda/xgmac.c |    4 ++++
 1 file changed, 4 insertions(+)

Comments

David Miller Jan. 18, 2013, 7:15 p.m.
From: Rob Herring <robherring2@gmail.com>
Date: Wed, 16 Jan 2013 17:36:37 -0600

> From: Rob Herring <rob.herring@calxeda.com>
> 
> 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>

Applied.
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diff --git a/drivers/net/ethernet/calxeda/xgmac.c b/drivers/net/ethernet/calxeda/xgmac.c
index b407043..f7f0290 100644
--- a/drivers/net/ethernet/calxeda/xgmac.c
+++ b/drivers/net/ethernet/calxeda/xgmac.c
@@ -548,6 +548,10 @@  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))