netfilter: nft_socket: fix erroneous socket assignment

The socket assignment is wrong, see skb_orphan():
When skb->destructor callback is not set, but skb->sk is set, this hits BUG().

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1651813
Fixes: 554ced0a6e29 ("netfilter: nf_tables: add support for native socket matching")
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
index d7f3776dfd719d402ae178890107db8ebd1627f2..637ce3e8c575ce1b95dfcd340347176772cdff2d 100644 (file)
--- a/net/netfilter/nft_socket.c
+++ b/net/netfilter/nft_socket.c
@@ -47,9 +47,6 @@ static void nft_socket_eval(const struct nft_expr *expr,
                return;
        }
 
-       /* So that subsequent socket matching not to require other lookups. */
-       skb->sk = sk;
-
        switch(priv->key) {
        case NFT_SOCKET_TRANSPARENT:
                nft_reg_store8(dest, inet_sk_transparent(sk));
@@ -66,6 +63,9 @@ static void nft_socket_eval(const struct nft_expr *expr,
                WARN_ON(1);
                regs->verdict.code = NFT_BREAK;
        }
+
+       if (sk != skb->sk)
+               sock_gen_put(sk);
 }
 
 static const struct nla_policy nft_socket_policy[NFTA_SOCKET_MAX + 1] = {