netdev - [PATCH 12/12] netfilter: nf_tables: reject unsupported chain flags

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Date:   Wed,  8 Jul 2020 19:46:09 +0200
From:   Pablo Neira Ayuso <pablo@...filter.org>
To:     netfilter-devel@...r.kernel.org
Cc:     davem@...emloft.net, netdev@...r.kernel.org, kuba@...nel.org
Subject: [PATCH 12/12] netfilter: nf_tables: reject unsupported chain flags

Bail out if userspace sends unsupported chain flags.

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

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index e00b4ae6174e..42f351c1f5c5 100644
--- 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
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index b8a970dad213..f96785586f64 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2285,6 +2285,9 @@ static int nf_tables_newchain(struct net *net, struct sock *nlsk,
 	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) {
-- 
2.20.1