netdev - [PATCH 04/13] netfilter: xt_NFLOG: fix unexpected truncated packet

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Date:   Fri, 21 Oct 2016 12:12:14 +0200
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     netfilter-devel@...r.kernel.org
Cc:     davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 04/13] netfilter: xt_NFLOG: fix unexpected truncated packet

From: Liping Zhang <liping.zhang@...eadtrum.com>

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@...idpixels.com>
Reported-by: Chris Caputo <ccaputo@....net>
Tested-by: Chris Caputo <ccaputo@....net>
Signed-off-by: Liping Zhang <liping.zhang@...eadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/xt_NFLOG.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/netfilter/xt_NFLOG.c b/net/netfilter/xt_NFLOG.c
index 018eed7e1ff1..8668a5c18dc3 100644
--- a/net/netfilter/xt_NFLOG.c
+++ b/net/netfilter/xt_NFLOG.c
@@ -32,6 +32,7 @@ nflog_tg(struct sk_buff *skb, const struct xt_action_param *par)
 	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;
-- 
2.1.4