[PATCH 4.8 122/138] netfilter: xt_NFLOG: fix unexpected truncated packet

[Greg Kroah-Hartman]

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

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

From: Liping Zhang <liping.zhang@xxxxxxxxxxxxxx>

commit 6d19375b58763fefc2f215fb45117d3353ced888 upstream.

Justin and Chris spotted that iptables NFLOG target was broken when they
upgraded the kernel to 4.8: "ulogd-2.0.5- IPs are no longer logged" or
"results in segfaults in ulogd-2.0.5".

Because "struct nf_loginfo li;" is a local variable, and flags will be
filled with garbage value, not inited to zero. So if it contains 0x1,
packets will not be logged to the userspace anymore.

Fixes: 7643507fe8b5 ("netfilter: xt_NFLOG: nflog-range does not truncate packets")
Reported-by: Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx>
Reported-by: Chris Caputo <ccaputo@xxxxxxx>
Tested-by: Chris Caputo <ccaputo@xxxxxxx>
Signed-off-by: Liping Zhang <liping.zhang@xxxxxxxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/netfilter/xt_NFLOG.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/netfilter/xt_NFLOG.c
+++ b/net/netfilter/xt_NFLOG.c
@@ -32,6 +32,7 @@ nflog_tg(struct sk_buff *skb, const stru
 	li.u.ulog.copy_len   = info->len;
 	li.u.ulog.group	     = info->group;
 	li.u.ulog.qthreshold = info->threshold;
+	li.u.ulog.flags	     = 0;
 
 	if (info->flags & XT_NFLOG_F_COPY_LEN)
 		li.u.ulog.flags |= NF_LOG_F_COPY_LEN;