From: Phil Sutter phil@nwl.cc

commit f1082dd31fe461d482d69da2a8eccfeb7bf07ac2 upstream.

An nftables family is merely a hollow container, its family just a number and such not reliant on compile-time options other than nftables support itself. Add an artificial check so attempts at using a family the kernel can't support fail as early as possible. This helps user space detect kernels which lack e.g. NFPROTO_INET.

Signed-off-by: Phil Sutter phil@nwl.cc Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Cengiz Can cengiz.can@canonical.com --- net/netfilter/nf_tables_api.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 78be121f38ac..915df77161e1 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -1005,6 +1005,30 @@ static int nft_objname_hash_cmp(struct rhashtable_compare_arg *arg, return strcmp(obj->key.name, k->name); }

+static bool nft_supported_family(u8 family) +{ + return false +#ifdef CONFIG_NF_TABLES_INET + || family == NFPROTO_INET +#endif +#ifdef CONFIG_NF_TABLES_IPV4 + || family == NFPROTO_IPV4 +#endif +#ifdef CONFIG_NF_TABLES_ARP + || family == NFPROTO_ARP +#endif +#ifdef CONFIG_NF_TABLES_NETDEV + || family == NFPROTO_NETDEV +#endif +#if IS_ENABLED(CONFIG_NF_TABLES_BRIDGE) + || family == NFPROTO_BRIDGE +#endif +#ifdef CONFIG_NF_TABLES_IPV6 + || family == NFPROTO_IPV6 +#endif + ; +} + static int nf_tables_newtable(struct net *net, struct sock *nlsk, struct sk_buff *skb, const struct nlmsghdr *nlh, const struct nlattr * const nla[], @@ -1020,6 +1044,9 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk, struct nft_ctx ctx; int err;

+ if (!nft_supported_family(family)) + return -EOPNOTSUPP; + lockdep_assert_held(&nft_net->commit_mutex); attr = nla[NFTA_TABLE_NAME]; table = nft_table_lookup(net, attr, family, genmask);