netdev - [PATCH] netfilter/nflog: nflog-range does not truncate packets

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Date:	Wed, 1 Jun 2016 20:23:54 -0400
From:	Vishwanath Pai <vpai@...mai.com>
To:	pablo@...filter.org, kaber@...sh.net, kadlec@...ckhole.kfki.hu,
	netfilter-devel@...r.kernel.org
Cc:	coreteam@...filter.org, johunt@...mai.com, netdev@...r.kernel.org,
	pai.vishwain@...il.com
Subject: [PATCH] netfilter/nflog: nflog-range does not truncate packets

netfilter/nflog: nflog-range does not truncate packets

The --nflog-range parameter from userspace is ignored in the kernel and
the entire packet is sent to the userspace. The per-instance parameter
copy_range still works, with this change --nflog-range will have
preference over copy_range.

Signed-off-by: Vishwanath Pai <vpai@...mai.com>
Reviewed-by: Joshua Hunt <johunt@...mai.com>

diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index 4ef1fae..f40ddba 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -680,7 +680,6 @@ nfulnl_log_packet(struct net *net,
 		if (qthreshold > li->u.ulog.qthreshold)
 			qthreshold = li->u.ulog.qthreshold;
 
-
 	switch (inst->copy_mode) {
 	case NFULNL_COPY_META:
 	case NFULNL_COPY_NONE:
@@ -688,10 +687,12 @@ nfulnl_log_packet(struct net *net,
 		break;
 
 	case NFULNL_COPY_PACKET:
-		if (inst->copy_range > skb->len)
+		data_len = inst->copy_range;
+		if (li->u.ulog.copy_len < data_len)
+			data_len = li->u.ulog.copy_len;
+
+		if (data_len > skb->len)
 			data_len = skb->len;
-		else
-			data_len = inst->copy_range;
 
 		size += nla_total_size(data_len);
 		break;