From 18bbc3213383a82b05383827f4b1b882e3f0a5a5 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sat, 20 Aug 2022 17:54:06 +0200 Subject: [PATCH] netfilter: nft_tproxy: restrict to prerouting hook TPROXY is only allowed from prerouting, but nft_tproxy doesn't check this. This fixes a crash (null dereference) when using tproxy from e.g. output. Fixes: 4ed8eb6570a4 ("netfilter: nf_tables: Add native tproxy support") Reported-by: Shell Chen Signed-off-by: Florian Westphal --- net/netfilter/nft_tproxy.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/netfilter/nft_tproxy.c b/net/netfilter/nft_tproxy.c index 68b2eed742df..62da25ad264b 100644 --- a/net/netfilter/nft_tproxy.c +++ b/net/netfilter/nft_tproxy.c @@ -312,6 +312,13 @@ static int nft_tproxy_dump(struct sk_buff *skb, return 0; } +static int nft_tproxy_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr, + const struct nft_data **data) +{ + return nft_chain_validate_hooks(ctx->chain, 1 << NF_INET_PRE_ROUTING); +} + static struct nft_expr_type nft_tproxy_type; static const struct nft_expr_ops nft_tproxy_ops = { .type = &nft_tproxy_type, @@ -321,6 +328,7 @@ static const struct nft_expr_ops nft_tproxy_ops = { .destroy = nft_tproxy_destroy, .dump = nft_tproxy_dump, .reduce = NFT_REDUCE_READONLY, + .validate = nft_tproxy_validate, }; static struct nft_expr_type nft_tproxy_type __read_mostly = { -- 2.39.5