netdev - [PATCH 12/15] netfilter: xt_HL: prefer skb_ensure

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Date:   Sat,  1 Jun 2019 20:23:37 +0200
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     netfilter-devel@...r.kernel.org
Cc:     davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 12/15] netfilter: xt_HL: prefer skb_ensure_writable

From: Florian Westphal <fw@...len.de>

Also, make the argument to be only the needed size of the header
we're altering, no need to pull in the full packet into linear area.

Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/xt_HL.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/xt_HL.c b/net/netfilter/xt_HL.c
index 4653b071bed4..a37b8824221f 100644
--- a/net/netfilter/xt_HL.c
+++ b/net/netfilter/xt_HL.c
@@ -32,7 +32,7 @@ ttl_tg(struct sk_buff *skb, const struct xt_action_param *par)
 	const struct ipt_TTL_info *info = par->targinfo;
 	int new_ttl;
 
-	if (!skb_make_writable(skb, skb->len))
+	if (skb_ensure_writable(skb, sizeof(*iph)))
 		return NF_DROP;
 
 	iph = ip_hdr(skb);
@@ -72,7 +72,7 @@ hl_tg6(struct sk_buff *skb, const struct xt_action_param *par)
 	const struct ip6t_HL_info *info = par->targinfo;
 	int new_hl;
 
-	if (!skb_make_writable(skb, skb->len))
+	if (skb_ensure_writable(skb, sizeof(*ip6h)))
 		return NF_DROP;
 
 	ip6h = ipv6_hdr(skb);
-- 
2.11.0