From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7E90726CE07; Wed, 8 Oct 2025 12:59:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759928395; cv=none; b=Y422kAGq/fpA8SIb1/ZYDDNOmP/oFGnTDFPL+IBt/GNj5nd253HAhwcUvzZfP7QUAnDDUpr8MtfdheCLLsZZd25acHZ0TpGhwhSEzSKi5bfP6Zk5Pj804ZgXohyXnUDgUyq4AxRw0q3FnvV6GzsvRL4EDBH8WuIb23xzWIKy67k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759928395; c=relaxed/simple; bh=yWO99/d8EoLPqWM1cGMW9x0Dwe6pjhvIfrsXVa81Ebs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=nK7uVC1L3o6Ipg2REEznwnkEKZ1qRXw1RMJEyvT3zpxlg+zdXFDdu32C4m1lLUwLyUy/YcaaOD8atF2K7DFWzKMaqjp4oS4TVOnOL9/k9U8VIKJs7CaqvQFW9k2RzTRt6DNWavtVQEPFnUL1dN4SRnQOixrILgiMemnY5nPWKkQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id 7E4A860321; Wed, 8 Oct 2025 14:59:51 +0200 (CEST) From: Florian Westphal To: Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , , pablo@netfilter.org Subject: [PATCH net 1/4] netfilter: nft_objref: validate objref and objrefmap expressions Date: Wed, 8 Oct 2025 14:59:39 +0200 Message-ID: <20251008125942.25056-2-fw@strlen.de> X-Mailer: git-send-email 2.49.1 In-Reply-To: <20251008125942.25056-1-fw@strlen.de> References: <20251008125942.25056-1-fw@strlen.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Fernando Fernandez Mancera Referencing a synproxy stateful object from OUTPUT hook causes kernel crash due to infinite recursive calls: BUG: TASK stack guard page was hit at 000000008bda5b8c (stack is 000000003ab1c4a5..00000000494d8b12) [...] Call Trace: __find_rr_leaf+0x99/0x230 fib6_table_lookup+0x13b/0x2d0 ip6_pol_route+0xa4/0x400 fib6_rule_lookup+0x156/0x240 ip6_route_output_flags+0xc6/0x150 __nf_ip6_route+0x23/0x50 synproxy_send_tcp_ipv6+0x106/0x200 synproxy_send_client_synack_ipv6+0x1aa/0x1f0 nft_synproxy_do_eval+0x263/0x310 nft_do_chain+0x5a8/0x5f0 [nf_tables nft_do_chain_inet+0x98/0x110 nf_hook_slow+0x43/0xc0 __ip6_local_out+0xf0/0x170 ip6_local_out+0x17/0x70 synproxy_send_tcp_ipv6+0x1a2/0x200 synproxy_send_client_synack_ipv6+0x1aa/0x1f0 [...] Implement objref and objrefmap expression validate functions. Currently, only NFT_OBJECT_SYNPROXY object type requires validation. This will also handle a jump to a chain using a synproxy object from the OUTPUT hook. Now when trying to reference a synproxy object in the OUTPUT hook, nft will produce the following error: synproxy_crash.nft: Error: Could not process rule: Operation not supported synproxy name mysynproxy ^^^^^^^^^^^^^^^^^^^^^^^^ Fixes: ee394f96ad75 ("netfilter: nft_synproxy: add synproxy stateful object support") Reported-by: Georg Pfuetzenreuter Closes: https://bugzilla.suse.com/1250237 Signed-off-by: Fernando Fernandez Mancera Signed-off-by: Florian Westphal --- net/netfilter/nft_objref.c | 39 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/net/netfilter/nft_objref.c b/net/netfilter/nft_objref.c index 8ee66a86c3bc..1a62e384766a 100644 --- a/net/netfilter/nft_objref.c +++ b/net/netfilter/nft_objref.c @@ -22,6 +22,35 @@ void nft_objref_eval(const struct nft_expr *expr, obj->ops->eval(obj, regs, pkt); } +static int nft_objref_validate_obj_type(const struct nft_ctx *ctx, u32 type) +{ + unsigned int hooks; + + switch (type) { + case NFT_OBJECT_SYNPROXY: + if (ctx->family != NFPROTO_IPV4 && + ctx->family != NFPROTO_IPV6 && + ctx->family != NFPROTO_INET) + return -EOPNOTSUPP; + + hooks = (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD); + + return nft_chain_validate_hooks(ctx->chain, hooks); + default: + break; + } + + return 0; +} + +static int nft_objref_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr) +{ + struct nft_object *obj = nft_objref_priv(expr); + + return nft_objref_validate_obj_type(ctx, obj->ops->type->type); +} + static int nft_objref_init(const struct nft_ctx *ctx, const struct nft_expr *expr, const struct nlattr * const tb[]) @@ -93,6 +122,7 @@ static const struct nft_expr_ops nft_objref_ops = { .activate = nft_objref_activate, .deactivate = nft_objref_deactivate, .dump = nft_objref_dump, + .validate = nft_objref_validate, .reduce = NFT_REDUCE_READONLY, }; @@ -197,6 +227,14 @@ static void nft_objref_map_destroy(const struct nft_ctx *ctx, nf_tables_destroy_set(ctx, priv->set); } +static int nft_objref_map_validate(const struct nft_ctx *ctx, + const struct nft_expr *expr) +{ + const struct nft_objref_map *priv = nft_expr_priv(expr); + + return nft_objref_validate_obj_type(ctx, priv->set->objtype); +} + static const struct nft_expr_ops nft_objref_map_ops = { .type = &nft_objref_type, .size = NFT_EXPR_SIZE(sizeof(struct nft_objref_map)), @@ -206,6 +244,7 @@ static const struct nft_expr_ops nft_objref_map_ops = { .deactivate = nft_objref_map_deactivate, .destroy = nft_objref_map_destroy, .dump = nft_objref_map_dump, + .validate = nft_objref_map_validate, .reduce = NFT_REDUCE_READONLY, }; -- 2.49.1