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@xxxxxx>
---
Changes since v2:
- Casting family from u8 to int via parameter resulted in an always
negative result. Pass it as u8 to nft_supported_family().
- Fix typo: CONIFG_NF_TABLES_BRIDGE -> CONFIG_NF_TABLES_BRIDGE
- Reduce the function to a single statement instead of if/else
conditional.
- Use 'false' instead of '0' for the standard term.
Changes since v1:
- Avoid a compiler warning if none of the tested symbols are enabled.
---
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 5fa16990da951..ac33ca9f8d88b 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1072,6 +1072,30 @@ 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 sk_buff *skb, const struct nfnl_info *info,
const struct nlattr * const nla[])
{
@@ -1086,6 +1110,9 @@ static int nf_tables_newtable(struct sk_buff *skb, const struct nfnl_info *info,
u32 flags = 0;
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,
--
2.34.1
