netfilter: nf_tables: validate hooks in NAT expressions
The user can crash the kernel if it uses any of the existing NAT
expressions from the wrong hook, so add some code to validate this
when loading the rule.
This patch introduces nft_chain_validate_hooks() which is based on
an existing function in the bridge version of the reject expression.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nft_masq.c b/net/netfilter/nft_masq.c
index d1ffd5e..9aea747 100644
--- a/net/netfilter/nft_masq.c
+++ b/net/netfilter/nft_masq.c
@@ -21,6 +21,21 @@
};
EXPORT_SYMBOL_GPL(nft_masq_policy);
+int nft_masq_validate(const struct nft_ctx *ctx,
+ const struct nft_expr *expr,
+ const struct nft_data **data)
+{
+ int err;
+
+ err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
+ if (err < 0)
+ return err;
+
+ return nft_chain_validate_hooks(ctx->chain,
+ (1 << NF_INET_POST_ROUTING));
+}
+EXPORT_SYMBOL_GPL(nft_masq_validate);
+
int nft_masq_init(const struct nft_ctx *ctx,
const struct nft_expr *expr,
const struct nlattr * const tb[])
@@ -28,8 +43,8 @@
struct nft_masq *priv = nft_expr_priv(expr);
int err;
- err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
- if (err < 0)
+ err = nft_masq_validate(ctx, expr, NULL);
+ if (err)
return err;
if (tb[NFTA_MASQ_FLAGS] == NULL)
@@ -60,12 +75,5 @@
}
EXPORT_SYMBOL_GPL(nft_masq_dump);
-int nft_masq_validate(const struct nft_ctx *ctx, const struct nft_expr *expr,
- const struct nft_data **data)
-{
- return nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
-}
-EXPORT_SYMBOL_GPL(nft_masq_validate);
-
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>");
