Merge git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf

Pablo Neira Ayuso says:

====================
Netfilter fixes for net

1) Don't refresh timeout for SCTP flows in CLOSED state.

2) Don't allow access to transport header if fragment offset is set on.

3) Reinitialize internal conntrack state for retransmitted TCP
   syn-ack packet.

4) Update MAINTAINER file to add the Netfilter group tree. Moving
   forward, Florian Westphal has access to this tree so he can also
   send pull requests.

5) Set on IPS_HELPER for entries created via ctnetlink, otherwise NAT
   might zap it.

All patches from Florian Westphal.

* git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf:
  netfilter: ctnetlink: disable helper autoassign
  MAINTAINERS: netfilter: update git links
  netfilter: conntrack: re-init state for retransmitted syn-ack
  netfilter: conntrack: move synack init code to helper
  netfilter: nft_payload: don't allow th access for fragments
  netfilter: conntrack: don't refresh sctp entries in closed state
====================

Link: https://lore.kernel.org/r/20220204151903.320786-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

5 files changed, 58 insertions, 24 deletions

diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index ac438370f94a..7032402ffd33 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -2311,7 +2311,8 @@ ctnetlink_create_conntrack(struct net *net,
 			if (helper->from_nlattr)
 				helper->from_nlattr(helpinfo, ct);
 
-			/* not in hash table yet so not strictly necessary */
+			/* disable helper auto-assignment for this entry */
+			ct->status |= IPS_HELPER;
 			RCU_INIT_POINTER(help->helper, helper);
 		}
 	} else {
diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c
index 2394238d01c9..5a936334b517 100644
--- a/net/netfilter/nf_conntrack_proto_sctp.c
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -489,6 +489,15 @@ int nf_conntrack_sctp_packet(struct nf_conn *ct,
 			pr_debug("Setting vtag %x for dir %d\n",
 				 ih->init_tag, !dir);
 			ct->proto.sctp.vtag[!dir] = ih->init_tag;
+
+			/* don't renew timeout on init retransmit so
+			 * port reuse by client or NAT middlebox cannot
+			 * keep entry alive indefinitely (incl. nat info).
+			 */
+			if (new_state == SCTP_CONNTRACK_CLOSED &&
+			    old_state == SCTP_CONNTRACK_CLOSED &&
+			    nf_ct_is_confirmed(ct))
+				ignore = true;
 		}
 
 		ct->proto.sctp.state = new_state;
diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c
index af5115e127cf..d1582b888c0d 100644
--- a/net/netfilter/nf_conntrack_proto_tcp.c
+++ b/net/netfilter/nf_conntrack_proto_tcp.c
@@ -446,6 +446,32 @@ static void tcp_sack(const struct sk_buff *skb, unsigned int dataoff,
 	}
 }
 
+static void tcp_init_sender(struct ip_ct_tcp_state *sender,
+			    struct ip_ct_tcp_state *receiver,
+			    const struct sk_buff *skb,
+			    unsigned int dataoff,
+			    const struct tcphdr *tcph,
+			    u32 end, u32 win)
+{
+	/* SYN-ACK in reply to a SYN
+	 * or SYN from reply direction in simultaneous open.
+	 */
+	sender->td_end =
+	sender->td_maxend = end;
+	sender->td_maxwin = (win == 0 ? 1 : win);
+
+	tcp_options(skb, dataoff, tcph, sender);
+	/* RFC 1323:
+	 * Both sides must send the Window Scale option
+	 * to enable window scaling in either direction.
+	 */
+	if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE &&
+	      receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE)) {
+		sender->td_scale = 0;
+		receiver->td_scale = 0;
+	}
+}
+
 static bool tcp_in_window(struct nf_conn *ct,
 			  enum ip_conntrack_dir dir,
 			  unsigned int index,
@@ -499,24 +525,9 @@ static bool tcp_in_window(struct nf_conn *ct,
 		 * Initialize sender data.
 		 */
 		if (tcph->syn) {
-			/*
-			 * SYN-ACK in reply to a SYN
-			 * or SYN from reply direction in simultaneous open.
-			 */
-			sender->td_end =
-			sender->td_maxend = end;
-			sender->td_maxwin = (win == 0 ? 1 : win);
-
-			tcp_options(skb, dataoff, tcph, sender);
-			/*
-			 * RFC 1323:
-			 * Both sides must send the Window Scale option
-			 * to enable window scaling in either direction.
-			 */
-			if (!(sender->flags & IP_CT_TCP_FLAG_WINDOW_SCALE
-			      && receiver->flags & IP_CT_TCP_FLAG_WINDOW_SCALE))
-				sender->td_scale =
-				receiver->td_scale = 0;
+			tcp_init_sender(sender, receiver,
+					skb, dataoff, tcph,
+					end, win);
 			if (!tcph->ack)
 				/* Simultaneous open */
 				return true;
@@ -560,6 +571,18 @@ static bool tcp_in_window(struct nf_conn *ct,
 		sender->td_maxwin = (win == 0 ? 1 : win);
 
 		tcp_options(skb, dataoff, tcph, sender);
+	} else if (tcph->syn && dir == IP_CT_DIR_REPLY &&
+		   state->state == TCP_CONNTRACK_SYN_SENT) {
+		/* Retransmitted syn-ack, or syn (simultaneous open).
+		 *
+		 * Re-init state for this direction, just like for the first
+		 * syn(-ack) reply, it might differ in seq, ack or tcp options.
+		 */
+		tcp_init_sender(sender, receiver,
+				skb, dataoff, tcph,
+				end, win);
+		if (!tcph->ack)
+			return true;
 	}
 
 	if (!(tcph->ack)) {
diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c
index dbe1f2e7dd9e..9e927ab4df15 100644
--- a/net/netfilter/nft_exthdr.c
+++ b/net/netfilter/nft_exthdr.c
@@ -167,7 +167,7 @@ nft_tcp_header_pointer(const struct nft_pktinfo *pkt,
 {
 	struct tcphdr *tcph;
 
-	if (pkt->tprot != IPPROTO_TCP)
+	if (pkt->tprot != IPPROTO_TCP || pkt->fragoff)
 		return NULL;
 
 	tcph = skb_header_pointer(pkt->skb, nft_thoff(pkt), sizeof(*tcph), buffer);
diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c
index 940fed9a760b..5cc06aef4345 100644
--- a/net/netfilter/nft_payload.c
+++ b/net/netfilter/nft_payload.c
@@ -83,7 +83,7 @@ static int __nft_payload_inner_offset(struct nft_pktinfo *pkt)
 {
 	unsigned int thoff = nft_thoff(pkt);
 
-	if (!(pkt->flags & NFT_PKTINFO_L4PROTO))
+	if (!(pkt->flags & NFT_PKTINFO_L4PROTO) || pkt->fragoff)
 		return -1;
 
 	switch (pkt->tprot) {
@@ -147,7 +147,7 @@ void nft_payload_eval(const struct nft_expr *expr,
 		offset = skb_network_offset(skb);
 		break;
 	case NFT_PAYLOAD_TRANSPORT_HEADER:
-		if (!(pkt->flags & NFT_PKTINFO_L4PROTO))
+		if (!(pkt->flags & NFT_PKTINFO_L4PROTO) || pkt->fragoff)
 			goto err;
 		offset = nft_thoff(pkt);
 		break;
@@ -688,7 +688,7 @@ static void nft_payload_set_eval(const struct nft_expr *expr,
 		offset = skb_network_offset(skb);
 		break;
 	case NFT_PAYLOAD_TRANSPORT_HEADER:
-		if (!(pkt->flags & NFT_PKTINFO_L4PROTO))
+		if (!(pkt->flags & NFT_PKTINFO_L4PROTO) || pkt->fragoff)
 			goto err;
 		offset = nft_thoff(pkt);
 		break;
@@ -728,7 +728,8 @@ static void nft_payload_set_eval(const struct nft_expr *expr,
 	if (priv->csum_type == NFT_PAYLOAD_CSUM_SCTP &&
 	    pkt->tprot == IPPROTO_SCTP &&
 	    skb->ip_summed != CHECKSUM_PARTIAL) {
-		if (nft_payload_csum_sctp(skb, nft_thoff(pkt)))
+		if (pkt->fragoff == 0 &&
+		    nft_payload_csum_sctp(skb, nft_thoff(pkt)))
 			goto err;
 	}