netdev - [PATCH 2/3] [LLC]: bogus llc packet length

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Date:	Fri, 28 Mar 2008 16:59:35 +0900
From:	Joonwoo Park <joonwpark81@...il.com>
To:	davem@...emloft.net
Cc:	Joonwoo Park <joonwpark81@...il.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	netdev@...r.kernel.org
Subject: [PATCH 2/3] [LLC]: bogus llc packet length

discard llc packet which has bogus packet length.

Signed-off-by: Joonwoo Park <joonwpark81@...il.com>
Acked-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 net/llc/llc_input.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/net/llc/llc_input.c b/net/llc/llc_input.c
index c40c9b2..bfd2567 100644
--- a/net/llc/llc_input.c
+++ b/net/llc/llc_input.c
@@ -117,8 +117,12 @@ static inline int llc_fixup_skb(struct sk_buff *skb)
 	skb_pull(skb, llc_len);
 	if (skb->protocol == htons(ETH_P_802_2)) {
 		__be16 pdulen = eth_hdr(skb)->h_proto;
-		u16 data_size = ntohs(pdulen) - llc_len;
+		s32 data_size = ntohs(pdulen) - llc_len;
 
+		if (data_size < 0 ||
+		    ((skb_tail_pointer(skb) -
+		      (u8 *)pdu) - llc_len) < data_size)
+			return 0;
 		if (unlikely(pskb_trim_rcsum(skb, data_size)))
 			return 0;
 	}
-- 
1.5.4.3

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