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netfilter: nf_queue: don't assume sk is full socket

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commit 747670fd9a 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: ca6fb06518 ("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>
This commit is contained in:
Florian Westphal 2022-02-25 14:02:41 +01:00 • committed by Greg Kroah-Hartman
commit 3b9ba964f7
1 changed files with 10 additions and 1 deletions
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11
net/netfilter/nf_queue.c
View file

@ -46,6 +46,15 @@ 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
}
static void nf_queue_entry_release_refs(struct nf_queue_entry *entry)
{
struct nf_hook_state *state = &entry->state;
@ -56,7 +65,7 @@ static 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->physin)