From patchwork Wed Aug 17 13:59:59 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 12945915 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97E5EC28B2B for ; Wed, 17 Aug 2022 14:01:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239858AbiHQOBN (ORCPT ); Wed, 17 Aug 2022 10:01:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239863AbiHQOA4 (ORCPT ); Wed, 17 Aug 2022 10:00:56 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F0F979858F; Wed, 17 Aug 2022 07:00:55 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1oOJbK-0008O2-Cp; Wed, 17 Aug 2022 16:00:54 +0200 From: Florian Westphal To: netdev@vger.kernel.org Cc: , Pablo Neira Ayuso , Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski Subject: [PATCH net 01/17] netfilter: nf_tables: use READ_ONCE and WRITE_ONCE for shared generation id access Date: Wed, 17 Aug 2022 15:59:59 +0200 Message-Id: <20220817140015.25843-2-fw@strlen.de> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220817140015.25843-1-fw@strlen.de> References: <20220817140015.25843-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Pablo Neira Ayuso The generation ID is bumped from the commit path while holding the mutex, however, netlink dump operations rely on RCU. This patch also adds missing cb->base_eq initialization in nf_tables_dump_set(). Fixes: 38e029f14a97 ("netfilter: nf_tables: set NLM_F_DUMP_INTR if netlink dumping is stale") Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_tables_api.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 3cc88998b879..8b084cd669ab 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -889,7 +889,7 @@ static int nf_tables_dump_tables(struct sk_buff *skb, rcu_read_lock(); nft_net = nft_pernet(net); - cb->seq = nft_net->base_seq; + cb->seq = READ_ONCE(nft_net->base_seq); list_for_each_entry_rcu(table, &nft_net->tables, list) { if (family != NFPROTO_UNSPEC && family != table->family) @@ -1705,7 +1705,7 @@ static int nf_tables_dump_chains(struct sk_buff *skb, rcu_read_lock(); nft_net = nft_pernet(net); - cb->seq = nft_net->base_seq; + cb->seq = READ_ONCE(nft_net->base_seq); list_for_each_entry_rcu(table, &nft_net->tables, list) { if (family != NFPROTO_UNSPEC && family != table->family) @@ -3149,7 +3149,7 @@ static int nf_tables_dump_rules(struct sk_buff *skb, rcu_read_lock(); nft_net = nft_pernet(net); - cb->seq = nft_net->base_seq; + cb->seq = READ_ONCE(nft_net->base_seq); list_for_each_entry_rcu(table, &nft_net->tables, list) { if (family != NFPROTO_UNSPEC && family != table->family) @@ -4133,7 +4133,7 @@ static int nf_tables_dump_sets(struct sk_buff *skb, struct netlink_callback *cb) rcu_read_lock(); nft_net = nft_pernet(net); - cb->seq = nft_net->base_seq; + cb->seq = READ_ONCE(nft_net->base_seq); list_for_each_entry_rcu(table, &nft_net->tables, list) { if (ctx->family != NFPROTO_UNSPEC && @@ -5061,6 +5061,8 @@ static int nf_tables_dump_set(struct sk_buff *skb, struct netlink_callback *cb) rcu_read_lock(); nft_net = nft_pernet(net); + cb->seq = READ_ONCE(nft_net->base_seq); + list_for_each_entry_rcu(table, &nft_net->tables, list) { if (dump_ctx->ctx.family != NFPROTO_UNSPEC && dump_ctx->ctx.family != table->family) @@ -6941,7 +6943,7 @@ static int nf_tables_dump_obj(struct sk_buff *skb, struct netlink_callback *cb) rcu_read_lock(); nft_net = nft_pernet(net); - cb->seq = nft_net->base_seq; + cb->seq = READ_ONCE(nft_net->base_seq); list_for_each_entry_rcu(table, &nft_net->tables, list) { if (family != NFPROTO_UNSPEC && family != table->family) @@ -7873,7 +7875,7 @@ static int nf_tables_dump_flowtable(struct sk_buff *skb, rcu_read_lock(); nft_net = nft_pernet(net); - cb->seq = nft_net->base_seq; + cb->seq = READ_ONCE(nft_net->base_seq); list_for_each_entry_rcu(table, &nft_net->tables, list) { if (family != NFPROTO_UNSPEC && family != table->family) @@ -8806,6 +8808,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb) struct nft_trans_elem *te; struct nft_chain *chain; struct nft_table *table; + unsigned int base_seq; LIST_HEAD(adl); int err; @@ -8855,9 +8858,12 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb) * Bump generation counter, invalidate any dump in progress. * Cannot fail after this point. */ - while (++nft_net->base_seq == 0) + base_seq = READ_ONCE(nft_net->base_seq); + while (++base_seq == 0) ; + WRITE_ONCE(nft_net->base_seq, base_seq); + /* step 3. Start new generation, rules_gen_X now in use. */ net->nft.gencursor = nft_gencursor_next(net);