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

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Message-ID: <47e7678b.1aba720a.6925.fffff466@mx.google.com>
Date:	Mon, 24 Mar 2008 17:34:16 +0900
From:	joonwpark81@...il.com
To:	acme@...stprotocols.net
Cc:	Joonwoo Park <joonwpark81@...il.com>, netdev@...r.kernel.org
Subject: [PATCH 2/3] [LLC]: bogus llc packet length

From: Joonwoo Park <joonwpark81@...il.com>

discard llc packet which has bogus packet length.

Signed-off-by: Joonwoo Park <joonwpark81@...il.com>
---
diff --git a/net/llc/llc_input.c b/net/llc/llc_input.c
index c40c9b2..a2bbc7c 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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