[PATCH 4.4 19/56] netfilter: nft_meta: deal with PACKET_LOOPBACK in netdev family

From: Greg Kroah-Hartman
Date: Mon Nov 13 2017 - 07:58:03 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Liping Zhang <zlpnobody@xxxxxxxxx>


[ 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.

Signed-off-by: Liping Zhang <zlpnobody@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/netfilter/nft_meta.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)

--- a/net/netfilter/nft_meta.c
+++ b/net/netfilter/nft_meta.c
@@ -151,8 +151,34 @@ 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;