From 8dc3c2b86bb16e8f345b80a8af69696e9a7edb65 Mon Sep 17 00:00:00 2001 From: Liping Zhang Date: Thu, 15 Sep 2016 21:29:08 +0800 Subject: [PATCH] netfilter: nf_tables: improve nft payload fast eval There's an off-by-one issue in nft_payload_fast_eval, skb_tail_pointer and ptr + priv->len all point to the last valid address plus 1. So if they are equal, we can still fetch the valid data. It's unnecessary to fall back to nft_payload_eval. Signed-off-by: Liping Zhang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c index fb8b5892b5ff..36ba4e55d84e 100644 --- a/net/netfilter/nf_tables_core.c +++ b/net/netfilter/nf_tables_core.c @@ -98,7 +98,7 @@ static bool nft_payload_fast_eval(const struct nft_expr *expr, ptr += priv->offset; - if (unlikely(ptr + priv->len >= skb_tail_pointer(skb))) + if (unlikely(ptr + priv->len > skb_tail_pointer(skb))) return false; *dest = 0;