llc: Fix length check in llc_fixup_skb().

Fixes bugzilla #32872 The LLC stack pretends to support non-linear skbs but there is a direct use of skb_tail_pointer() in llc_fixup_skb(). Use pskb_may_pull() to see if data_size bytes remain and can be accessed linearly in the packet, instead of direct pointer checks. Signed-off-by: David S. Miller <[email protected]>
kawasaki · Apr 12, 2011 · aa86735 · aa86735
1 parent 4a9f65f
commit aa86735
Showing 1 changed file with 1 addition and 2 deletions.
diff --git a/net/llc/llc_input.c b/net/llc/llc_input.c
@@ -121,8 +121,7 @@ static inline int llc_fixup_skb(struct sk_buff *skb)
 		s32 data_size = ntohs(pdulen) - llc_len;
 
 		if (data_size < 0 ||
-		    ((skb_tail_pointer(skb) -
-		      (u8 *)pdu) - llc_len) < data_size)
+		    !pskb_may_pull(skb, data_size))
 			return 0;
 		if (unlikely(pskb_trim_rcsum(skb, data_size)))
 			return 0;