From f3600c867c99a2cc8038680ecf211089c50e7971 Mon Sep 17 00:00:00 2001 From: Mina Almasry Date: Thu, 6 Mar 2025 21:55:20 +0000 Subject: [PATCH] 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: 65249feb6b3d ("net: add support for skbs with unreadable frags") Suggested-by: Jakub Kicinski Cc: stable@vger.kernel.org Signed-off-by: Mina Almasry Link: https://patch.msgid.link/20250306215520.1415465-1-almasrymina@google.com Signed-off-by: Jakub Kicinski --- net/core/dev.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/core/dev.c b/net/core/dev.c index 30da277c5a6f..2f7f5fd9ffec 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -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)) -- 2.25.1