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 <oleksandr@redhat.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index 8f08d759844a9ab9eb24bf28a6f144e1207ad955..09e8d8a990de24ad4fcd6e3220af6bc6ec8bb293 100644 (file)
--- 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;