From 7210e4e38f945dfa173c4a4e59ad827c9ecad541 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Mon, 13 Oct 2014 19:50:22 +0200 Subject: netfilter: nf_tables: restrict nat/masq expressions to nat chain type This adds the missing validation code to avoid the use of nat/masq from non-nat chains. The validation assumes two possible configuration scenarios: 1) Use of nat from base chain that is not of nat type. Reject this configuration from the nft_*_init() path of the expression. 2) Use of nat from non-base chain. In this case, we have to wait until the non-base chain is referenced by at least one base chain via jump/goto. This is resolved from the nft_*_validate() path which is called from nf_tables_check_loops(). The user gets an -EOPNOTSUPP in both cases. Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_nat.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'net/netfilter/nft_nat.c') diff --git a/net/netfilter/nft_nat.c b/net/netfilter/nft_nat.c index 799550b476fb..0f0af6e86fb8 100644 --- a/net/netfilter/nft_nat.c +++ b/net/netfilter/nft_nat.c @@ -95,6 +95,10 @@ static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr, u32 family; int err; + err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT); + if (err < 0) + return err; + if (tb[NFTA_NAT_TYPE] == NULL) return -EINVAL; @@ -205,6 +209,13 @@ nla_put_failure: return -1; } +static int nft_nat_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); +} + static struct nft_expr_type nft_nat_type; static const struct nft_expr_ops nft_nat_ops = { .type = &nft_nat_type, @@ -212,6 +223,7 @@ static const struct nft_expr_ops nft_nat_ops = { .eval = nft_nat_eval, .init = nft_nat_init, .dump = nft_nat_dump, + .validate = nft_nat_validate, }; static struct nft_expr_type nft_nat_type __read_mostly = { -- cgit v1.2.3