From 491b1a866e4ad2f5b6f5d60a23e16ae77ec37d5c Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Thu, 17 May 2018 22:49:49 +0900 Subject: [PATCH] netfilter: nft_meta: fix wrong value dereference in nft_meta_set_eval commit 97a0549b15a0b466c47f6a0143a490a082c64b4e upstream. In the nft_meta_set_eval, nftrace value is dereferenced as u32 from sreg. But correct type is u8. so that sometimes incorrect value is dereferenced. Steps to reproduce: %nft add table ip filter %nft add chain ip filter input { type filter hook input priority 4\; } %nft add rule ip filter input nftrace set 0 %nft monitor Sometimes, we can see trace messages. trace id 16767227 ip filter input packet: iif "enp2s0" ether saddr xx:xx:xx:xx:xx:xx ether daddr xx:xx:xx:xx:xx:xx ip saddr 192.168.0.1 ip daddr 255.255.255.255 ip dscp cs0 ip ecn not-ect ip trace id 16767227 ip filter input rule nftrace set 0 (verdict continue) trace id 16767227 ip filter input verdict continue trace id 16767227 ip filter input Signed-off-by: Taehee Yoo Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nft_meta.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/net/netfilter/nft_meta.c b/net/netfilter/nft_meta.c index 5a60eb23a7ed..c71184d4eac1 100644 --- a/net/netfilter/nft_meta.c +++ b/net/netfilter/nft_meta.c @@ -229,7 +229,7 @@ void nft_meta_set_eval(const struct nft_expr *expr, struct sk_buff *skb = pkt->skb; u32 *sreg = ®s->data[meta->sreg]; u32 value = *sreg; - u8 pkt_type; + u8 value8; switch (meta->key) { case NFT_META_MARK: @@ -239,15 +239,17 @@ void nft_meta_set_eval(const struct nft_expr *expr, skb->priority = value; break; case NFT_META_PKTTYPE: - pkt_type = nft_reg_load8(sreg); + value8 = nft_reg_load8(sreg); - if (skb->pkt_type != pkt_type && - skb_pkt_type_ok(pkt_type) && + if (skb->pkt_type != value8 && + skb_pkt_type_ok(value8) && skb_pkt_type_ok(skb->pkt_type)) - skb->pkt_type = pkt_type; + skb->pkt_type = value8; break; case NFT_META_NFTRACE: - skb->nf_trace = !!value; + value8 = nft_reg_load8(sreg); + + skb->nf_trace = !!value8; break; default: WARN_ON(1);