From: Eric Dumazet <edumazet@google.com>
Date: Sat, 22 Sep 2012 00:08:29 +0000 (+0000)
Subject: ipv4: raw: fix icmp_filter()
X-Git-Tag: v3.2.31~12
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=65a484273f1b97019bcc923be0e47921b895ac30;p=karo-tx-linux.git

ipv4: raw: fix icmp_filter()

[ Upstream commit ab43ed8b7490cb387782423ecf74aeee7237e591 ]

icmp_filter() should not modify its input, or else its caller
would need to recompute ip_hdr() if skb->head is reallocated.

Use skb_header_pointer() instead of pskb_may_pull() and
change the prototype to make clear both sk and skb are const.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 007e2eb769d3..e1d4f30bb718 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -131,18 +131,20 @@ found:
  *	0 - deliver
  *	1 - block
  */
-static __inline__ int icmp_filter(struct sock *sk, struct sk_buff *skb)
+static int icmp_filter(const struct sock *sk, const struct sk_buff *skb)
 {
-	int type;
+	struct icmphdr _hdr;
+	const struct icmphdr *hdr;
 
-	if (!pskb_may_pull(skb, sizeof(struct icmphdr)))
+	hdr = skb_header_pointer(skb, skb_transport_offset(skb),
+				 sizeof(_hdr), &_hdr);
+	if (!hdr)
 		return 1;
 
-	type = icmp_hdr(skb)->type;
-	if (type < 32) {
+	if (hdr->type < 32) {
 		__u32 data = raw_sk(sk)->filter.data;
 
-		return ((1 << type) & data) != 0;
+		return ((1U << hdr->type) & data) != 0;
 	}
 
 	/* Do not block unknown ICMP types */