[PATCH net] net: dpaa: Pad packets to ETH_ZLEN

[Sean Anderson <sean.anderson@linux.dev>]

When sending packets under 60 bytes, up to three bytes of the buffer following
the data may be leaked. Avoid this by extending all packets to ETH_ZLEN,
ensuring nothing is leaked in the padding. This bug can be reproduced by
running

	$ ping -s 11 destination

Fixes: 9ad1a3749333 ("dpaa_eth: add support for DPAA Ethernet")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
---

 drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
index cfe6b57b1da0..e4e8ee8b7356 100644
--- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
+++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
@@ -2322,6 +2322,12 @@ dpaa_start_xmit(struct sk_buff *skb, struct net_device *net_dev)
 	}
 #endif
 
+	/* Packet data is always read as 32-bit words, so zero out any part of
+	 * the skb which might be sent if we have to pad the packet
+	 */
+	if (__skb_put_padto(skb, ETH_ZLEN, false))
+		goto enomem;
+
 	if (nonlinear) {
 		/* Just create a S/G fd based on the skb */
 		err = skb_to_sg_fd(priv, skb, &fd);
-- 
2.35.1.1320.gc452695387.dirty