From 1f18b7176e2e41fada24584ce3c80e9abfaca52b Mon Sep 17 00:00:00 2001
From: Mariusz Kozlowski <mk@lab.zgora.pl>
Date: Mon, 8 Nov 2010 11:58:45 +0000
Subject: [PATCH] net: Fix header size check for GSO case in recvmsg
 (af_packet)

Parameter 'len' is size_t type so it will never get negative.

Signed-off-by: Mariusz Kozlowski <mk@lab.zgora.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/packet/af_packet.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 0856a13cb53d80..8298e676f5a015 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1610,9 +1610,11 @@ static int packet_recvmsg(struct kiocb *iocb, struct socket *sock,
 
 		err = -EINVAL;
 		vnet_hdr_len = sizeof(vnet_hdr);
-		if ((len -= vnet_hdr_len) < 0)
+		if (len < vnet_hdr_len)
 			goto out_free;
 
+		len -= vnet_hdr_len;
+
 		if (skb_is_gso(skb)) {
 			struct skb_shared_info *sinfo = skb_shinfo(skb);
 
-- 
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