From e208bedb74b3f1487aea5590c4cad0cffc89dcc4 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Fri, 25 Feb 2022 14:02:41 +0100 Subject: [PATCH] netfilter: nf_queue: don't assume sk is full socket commit 747670fd9a2d1b7774030dba65ca022ba442ce71 upstream. There is no guarantee that state->sk refers to a full socket. If refcount transitions to 0, sock_put calls sk_free which then ends up with garbage fields. I'd like to thank Oleksandr Natalenko and Jiri Benc for considerable debug work and pointing out state->sk oddities. Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener") Tested-by: Oleksandr Natalenko Signed-off-by: Florian Westphal Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nf_queue.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c index b06ef4c62522..59340b3ef7ef 100644 --- a/net/netfilter/nf_queue.c +++ b/net/netfilter/nf_queue.c @@ -44,6 +44,15 @@ void nf_unregister_queue_handler(struct net *net) } EXPORT_SYMBOL(nf_unregister_queue_handler); +static void nf_queue_sock_put(struct sock *sk) +{ +#ifdef CONFIG_INET + sock_gen_put(sk); +#else + sock_put(sk); +#endif +} + void nf_queue_entry_release_refs(struct nf_queue_entry *entry) { struct nf_hook_state *state = &entry->state; @@ -54,7 +63,7 @@ void nf_queue_entry_release_refs(struct nf_queue_entry *entry) if (state->out) dev_put(state->out); if (state->sk) - sock_put(state->sk); + nf_queue_sock_put(state->sk); #if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) if (entry->skb->nf_bridge) { struct net_device *physdev;