From: Florian Westphal fw@strlen.de
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 oleksandr@redhat.com Signed-off-by: Florian Westphal fw@strlen.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/netfilter/nf_queue.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
--- a/net/netfilter/nf_queue.c +++ b/net/netfilter/nf_queue.c @@ -46,6 +46,15 @@ void nf_unregister_queue_handler(void) } 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 +} + static void nf_queue_entry_release_refs(struct nf_queue_entry *entry) { struct nf_hook_state *state = &entry->state; @@ -54,7 +63,7 @@ static void nf_queue_entry_release_refs( dev_put(state->in); dev_put(state->out); if (state->sk) - sock_put(state->sk); + nf_queue_sock_put(state->sk);
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER) dev_put(entry->physin);