6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit a42b69f692165ec39db42d595f4f65a4c8f42e44 ]
arp_xmit() can be called without RTNL or RCU protection.
Use RCU protection to avoid potential UAF.
Fixes: 29a26a568038 ("netfilter: Pass struct net into the netfilter hooks")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Reviewed-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Link: https://patch.msgid.link/20250207135841.1948589-5-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/ipv4/arp.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index ccff96820a703..8f9b5568f1dc1 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -658,10 +658,12 @@ static int arp_xmit_finish(struct net *net, struct sock *sk, struct sk_buff *skb
*/
void arp_xmit(struct sk_buff *skb)
{
+ rcu_read_lock();
/* Send it off, maybe filter it using firewalling first. */
NF_HOOK(NFPROTO_ARP, NF_ARP_OUT,
- dev_net(skb->dev), NULL, skb, NULL, skb->dev,
+ dev_net_rcu(skb->dev), NULL, skb, NULL, skb->dev,
arp_xmit_finish);
+ rcu_read_unlock();
}
EXPORT_SYMBOL(arp_xmit);
--
2.39.5
