Commit 743b83f1 authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso
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netfilter: nft_socket: only do sk lookups when indev is available 



Check if the incoming interface is available and NFT_BREAK
in case neither skb->sk nor input device are set.

Because nf_sk_lookup_slow*() assume packet headers are in the
'in' direction, use in postrouting is not going to yield a meaningful
result.  Same is true for the forward chain, so restrict the use
to prerouting, input and output.

Use in output work if a socket is already attached to the skb.

Fixes: 554ced0a ("netfilter: nf_tables: add support for native socket matching")
Reported-and-tested-by: default avatarTopi Miettinen <toiwoton@gmail.com>
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 626873c4

net/netfilter/nft_socket.c

+38 −14
Original line number Diff line number Diff line
@@ -54,34 +54,47 @@ nft_sock_get_eval_cgroupv2(u32 *dest, struct sock *sk, const struct nft_pktinfo 
}

#endif



static void nft_socket_eval(const struct nft_expr *expr,

			    struct nft_regs *regs,

			    const struct nft_pktinfo *pkt)

static struct sock *nft_socket_do_lookup(const struct nft_pktinfo *pkt)

{

	const struct nft_socket *priv = nft_expr_priv(expr);

	struct sk_buff *skb = pkt->skb;

	struct sock *sk = skb->sk;

	u32 *dest = &regs->data[priv->dreg];

	const struct net_device *indev = nft_in(pkt);

	const struct sk_buff *skb = pkt->skb;

	struct sock *sk = NULL;



	if (sk && !net_eq(nft_net(pkt), sock_net(sk)))

		sk = NULL;

	if (!indev)

		return NULL;



	if (!sk)

	switch (nft_pf(pkt)) {

	case NFPROTO_IPV4:

			sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, nft_in(pkt));

		sk = nf_sk_lookup_slow_v4(nft_net(pkt), skb, indev);

		break;

#if IS_ENABLED(CONFIG_NF_TABLES_IPV6)

	case NFPROTO_IPV6:

			sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, nft_in(pkt));

		sk = nf_sk_lookup_slow_v6(nft_net(pkt), skb, indev);

		break;

#endif

	default:

		WARN_ON_ONCE(1);

			regs->verdict.code = NFT_BREAK;

			return;

		break;

	}



	return sk;

}



static void nft_socket_eval(const struct nft_expr *expr,

			    struct nft_regs *regs,

			    const struct nft_pktinfo *pkt)

{

	const struct nft_socket *priv = nft_expr_priv(expr);

	struct sk_buff *skb = pkt->skb;

	struct sock *sk = skb->sk;

	u32 *dest = &regs->data[priv->dreg];



	if (sk && !net_eq(nft_net(pkt), sock_net(sk)))

		sk = NULL;



	if (!sk)

		sk = nft_socket_do_lookup(pkt);



	if (!sk) {

		regs->verdict.code = NFT_BREAK;

		return;
@@ -224,6 +237,16 @@ static bool nft_socket_reduce(struct nft_regs_track *track, 
	return nft_expr_reduce_bitwise(track, expr);

}



static int nft_socket_validate(const struct nft_ctx *ctx,

			       const struct nft_expr *expr,

			       const struct nft_data **data)

{

	return nft_chain_validate_hooks(ctx->chain,

					(1 << NF_INET_PRE_ROUTING) |

					(1 << NF_INET_LOCAL_IN) |

					(1 << NF_INET_LOCAL_OUT));

}



static struct nft_expr_type nft_socket_type;

static const struct nft_expr_ops nft_socket_ops = {

	.type		= &nft_socket_type,
@@ -231,6 +254,7 @@ static const struct nft_expr_ops nft_socket_ops = { 
	.eval		= nft_socket_eval,

	.init		= nft_socket_init,

	.dump		= nft_socket_dump,

	.validate	= nft_socket_validate,

	.reduce		= nft_socket_reduce,

};