From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Sat, 4 Jul 2020 02:51:28 +0200
Subject: netfilter: nf_tables: reject unsupported chain flags
Patch-mainline: v5.9-rc1
Git-commit: c1f79a2eefdcc0aef5d7a911c27a3f75f1936ecd
References: bsc#1176447

Bail out if userspace sends unsupported chain flags.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/uapi/linux/netfilter/nf_tables.h |    3 +++
 net/netfilter/nf_tables_api.c            |    3 +++
 2 files changed, 6 insertions(+)

--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -189,6 +189,9 @@ enum nft_chain_flags {
 	NFT_CHAIN_HW_OFFLOAD	= (1 << 1),
 	NFT_CHAIN_BINDING	= (1 << 2),
 };
+#define NFT_CHAIN_FLAGS		(NFT_CHAIN_BASE		| \
+				 NFT_CHAIN_HW_OFFLOAD	| \
+				 NFT_CHAIN_BINDING)
 
 /**
  * enum nft_chain_attributes - nf_tables chain netlink attributes
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2296,6 +2296,9 @@ static int nf_tables_newchain(struct net
 	else if (chain)
 		flags = chain->flags;
 
+	if (flags & ~NFT_CHAIN_FLAGS)
+		return -EOPNOTSUPP;
+
 	nft_ctx_init(&ctx, net, skb, nlh, family, table, chain, nla);
 
 	if (chain != NULL) {