Patch "netfilter: nft_meta: deal with PACKET_LOOPBACK in netdev family" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

netfilter: nft_meta: deal with PACKET_LOOPBACK in netdev family

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
netfilter-nft_meta-deal-with-packet_loopback-in-netdev-family.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Liping Zhang <[email protected]>
Date: Sat, 7 Jan 2017 21:33:55 +0800
Subject: netfilter: nft_meta: deal with PACKET_LOOPBACK in netdev family

From: Liping Zhang <[email protected]>

[ Upstream commit f169fd695b192dd7b23aff8e69d25a1bc881bbfa ]

After adding the following nft rule, then ping 224.0.0.1:

  # nft add rule netdev t c pkttype host counter

The warning complain message will be printed out again and again:

  WARNING: CPU: 0 PID: 10182 at net/netfilter/nft_meta.c:163 \
           nft_meta_get_eval+0x3fe/0x460 [nft_meta]
  [...]
  Call Trace:
  <IRQ>
  dump_stack+0x85/0xc2
  __warn+0xcb/0xf0
  warn_slowpath_null+0x1d/0x20
  nft_meta_get_eval+0x3fe/0x460 [nft_meta]
  nft_do_chain+0xff/0x5e0 [nf_tables]

So we should deal with PACKET_LOOPBACK in netdev family too. For ipv4, convert it to PACKET_BROADCAST/MULTICAST according to the destination address's type; For ipv6, convert it to PACKET_MULTICAST directly.

---
 net/netfilter/nft_meta.c |   28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

@@ -159,8 +159,34 @@ void nft_meta_get_eval(const struct nft_
 			else
 				*dest = PACKET_BROADCAST;
 			break;
+		case NFPROTO_NETDEV:
+			switch (skb->protocol) {
+			case htons(ETH_P_IP): {
+				int noff = skb_network_offset(skb);
+				struct iphdr *iph, _iph;
+
+				iph = skb_header_pointer(skb, noff,
+							 sizeof(_iph), &_iph);
+				if (!iph)
+					goto err;
+
+				if (ipv4_is_multicast(iph->daddr))
+					*dest = PACKET_MULTICAST;
+				else
+					*dest = PACKET_BROADCAST;
+
+				break;
+			}
+			case htons(ETH_P_IPV6):
+				*dest = PACKET_MULTICAST;
+				break;
+			default:
+				WARN_ON_ONCE(1);
+				goto err;
+			}
+			break;
 		default:
-			WARN_ON(1);
+			WARN_ON_ONCE(1);
 			goto err;
 		}
 		break;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/netfilter-nft_meta-deal-with-packet_loopback-in-netdev-family.patch