Fixes for 5.10

[thirdparty/kernel/stable-queue.git] / queue-5.10 / net-bridge-fix-corrupted-ethernet-header-on-multicas.patch

From 41b5528da82176293450cbcd7828aa73da9634b0 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Sun, 5 May 2024 20:42:38 +0200
Subject: net: bridge: fix corrupted ethernet header on multicast-to-unicast

From: Felix Fietkau <nbd@nbd.name>

[ Upstream commit 86b29d830ad69eecff25b22dc96c14c6573718e6 ]

The change from skb_copy to pskb_copy unfortunately changed the data
copying to omit the ethernet header, since it was pulled before reaching
this point. Fix this by calling __skb_push/pull around pskb_copy.

Fixes: 59c878cbcdd8 ("net: bridge: fix multicast-to-unicast with fraglist GSO")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/bridge/br_forward.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 3a70682e63524..ada03d49e7c1a 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -245,6 +245,7 @@ static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
 {
 	struct net_device *dev = BR_INPUT_SKB_CB(skb)->brdev;
 	const unsigned char *src = eth_hdr(skb)->h_source;
+	struct sk_buff *nskb;
 
 	if (!should_deliver(p, skb))
 		return;
@@ -253,12 +254,16 @@ static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
 	if (skb->dev == p->dev && ether_addr_equal(src, addr))
 		return;
 
-	skb = pskb_copy(skb, GFP_ATOMIC);
-	if (!skb) {
+	__skb_push(skb, ETH_HLEN);
+	nskb = pskb_copy(skb, GFP_ATOMIC);
+	__skb_pull(skb, ETH_HLEN);
+	if (!nskb) {
 		DEV_STATS_INC(dev, tx_dropped);
 		return;
 	}
 
+	skb = nskb;
+	__skb_pull(skb, ETH_HLEN);
 	if (!is_broadcast_ether_addr(addr))
 		memcpy(eth_hdr(skb)->h_dest, addr, ETH_ALEN);
 
-- 
2.43.0