Commit f3600c86 authored by Mina Almasry's avatar Mina Almasry Committed by Jakub Kicinski
Browse files

netmem: prevent TX of unreadable skbs 



Currently on stable trees we have support for netmem/devmem RX but not
TX. It is not safe to forward/redirect an RX unreadable netmem packet
into the device's TX path, as the device may call dma-mapping APIs on
dma addrs that should not be passed to it.

Fix this by preventing the xmit of unreadable skbs.

Tested by configuring tc redirect:

sudo tc qdisc add dev eth1 ingress
sudo tc filter add dev eth1 ingress protocol ip prio 1 flower ip_proto \
	tcp src_ip 192.168.1.12 action mirred egress redirect dev eth1

Before, I see unreadable skbs in the driver's TX path passed to dma
mapping APIs.

After, I don't see unreadable skbs in the driver's TX path passed to dma
mapping APIs.

Fixes: 65249feb ("net: add support for skbs with unreadable frags")
Suggested-by: default avatarJakub Kicinski <kuba@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMina Almasry <almasrymina@google.com>
Link: https://patch.msgid.link/20250306215520.1415465-1-almasrymina@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 8ef0f2c0

net/core/dev.c

+3 −0
Original line number Diff line number Diff line
@@ -3872,6 +3872,9 @@ static struct sk_buff *validate_xmit_skb(struct sk_buff *skb, struct net_device 
{

	netdev_features_t features;



	if (!skb_frags_readable(skb))

		goto out_kfree_skb;



	features = netif_skb_features(skb);

	skb = validate_xmit_vlan(skb, features);

	if (unlikely(!skb))