From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (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 C18AB219A7D; Thu, 29 May 2025 09:18:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.190.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748510325; cv=none; b=n5pdyOiig1OBHy9DhmrG5OTF1hi7kULLkreDht3wjkYH9cVmGz6TOXV/Pjl24BJKa/hrOfFnW+fax/rQWkCr/yMZi697DMmYHplHkjQHR49N37uJ+tvqvikJE8Fi5ug4caeZs8YIdHFws9Qay07ytrFLyjKnZd6uH2teUBtGElw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748510325; c=relaxed/simple; bh=DfSbHPCa6MxWvF44YVVS/IEpR9XOyDybF+XGjvCxaIM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=L84KohuvEgeSTe16xdSKK/+tsC+EQTvDoCoyrc1IlBT/L2vFatSX8RbgvlgRJKwSZEhSWGrgYkeOnh8o4vKZmyJDTdGPvTqRkmCKbzECHwYypcbW0g9j7Et95i7Ld7DieU3+HCppSEkP/y52HtNA8A3xT8P0QMmMJV1uLkqusNw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=QL7eV3TH; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=ignFCIOH; arc=none smtp.client-ip=217.70.190.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b="QL7eV3TH"; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b="ignFCIOH" Received: by mail.netfilter.org (Postfix, from userid 109) id 20D6860753; Thu, 29 May 2025 11:11:53 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1748509913; bh=1u9kumkznwUAxM5bTg9/ePa4WAoFSmRHyu7Y+ifICh0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QL7eV3THbVcXwti7cOdVqBmIv4dItxh5VwT6YCdCCd8thNcl5ebQEBKYaUEnRvnIr ltbR/+vy+P73/LYmVJ08PUgXgTdcD3wmq8W2hjHjD4RerglECnicYujFNKE+CZSiHt j9O42WLz7S3FAeAObzqXzQoPD+zQm5A6XDMzlLDky4aPvZRflUmS9UlhUkXAjAcwwW iKkxiPx4XlV0cDLXxpumxT6WBnauDwlMuij0O99jNAujzclKBraIOjiwCauWsx4qb9 Wnek5eDlZs9wL3IlMYcew+nwFLzuWLGkz1+0KFc8QvH+H4R/PE1k+3Jg8DRHwG4p82 dB4kz2ipebHvg== X-Spam-Level: Received: from localhost.localdomain (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id B8AA160750; Thu, 29 May 2025 11:11:50 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1748509910; bh=1u9kumkznwUAxM5bTg9/ePa4WAoFSmRHyu7Y+ifICh0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ignFCIOHyzqf6GvJmnCSjH/7GVyjg/F3yhMzZtP8C4R1nEi2iZwPESU5mTHZbJ4Wv GA+uiOYZVAJQxO1zmgZpPsEaIJJryvw3q+A9XOHp7eDSKeMD8iaxhHKQyOvkqAYya+ /MP0EyachY5wDD+9dqu/23/Lf1vETA/OI2Sc1xOcCZyBVyy8GPZXOiXNw2iG2i7zcb IInKc3kvwgFnZcAzDS2g/TGou6IOruBrS88EDdEl8EN+0D+oCJQoDV8PGGActUVmlv dRhnc0fZsoKZFh3Dzlcw1hBWI5RtJoVsV6fLvDYjV9VePgEBeMCo8mxWerTMOwLbCi rjbFHRldYA2VA== From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: gregkh@linuxfoundation.org, sashal@kernel.org, stable@vger.kernel.org Subject: [PATCH -stable,5.4 3/3] netfilter: nf_tables: do not defer rule destruction via call_rcu Date: Thu, 29 May 2025 11:11:44 +0200 Message-Id: <20250529091144.118355-4-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20250529091144.118355-1-pablo@netfilter.org> References: <20250529091144.118355-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Florian Westphal commit b04df3da1b5c6f6dc7cdccc37941740c078c4043 upstream. nf_tables_chain_destroy can sleep, it can't be used from call_rcu callbacks. Moreover, nf_tables_rule_release() is only safe for error unwinding, while transaction mutex is held and the to-be-desroyed rule was not exposed to either dataplane or dumps, as it deactives+frees without the required synchronize_rcu() in-between. nft_rule_expr_deactivate() callbacks will change ->use counters of other chains/sets, see e.g. nft_lookup .deactivate callback, these must be serialized via transaction mutex. Also add a few lockdep asserts to make this more explicit. Calling synchronize_rcu() isn't ideal, but fixing this without is hard and way more intrusive. As-is, we can get: WARNING: .. net/netfilter/nf_tables_api.c:5515 nft_set_destroy+0x.. Workqueue: events nf_tables_trans_destroy_work RIP: 0010:nft_set_destroy+0x3fe/0x5c0 Call Trace: nf_tables_trans_destroy_work+0x6b7/0xad0 process_one_work+0x64a/0xce0 worker_thread+0x613/0x10d0 In case the synchronize_rcu becomes an issue, we can explore alternatives. One way would be to allocate nft_trans_rule objects + one nft_trans_chain object, deactivate the rules + the chain and then defer the freeing to the nft destroy workqueue. We'd still need to keep the synchronize_rcu path as a fallback to handle -ENOMEM corner cases though. Reported-by: syzbot+b26935466701e56cfdc2@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67478d92.050a0220.253251.0062.GAE@google.com/T/ Fixes: c03d278fdf35 ("netfilter: nf_tables: wait for rcu grace period on net_device removal") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_tables.h | 3 --- net/netfilter/nf_tables_api.c | 31 ++++++++++++++----------------- 2 files changed, 14 insertions(+), 20 deletions(-) diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 566370938939..92551a765a44 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -899,7 +899,6 @@ struct nft_chain { u8 flags:6, genmask:2; char *name; - struct rcu_head rcu_head; /* Only used during control plane commit phase: */ struct nft_rule **rules_next; @@ -1016,7 +1015,6 @@ static inline void nft_use_inc_restore(u32 *use) * @sets: sets in the table * @objects: stateful objects in the table * @flowtables: flow tables in the table - * @net: netnamespace this table belongs to * @hgenerator: handle generator state * @handle: table handle * @use: number of chain references to this table @@ -1032,7 +1030,6 @@ struct nft_table { struct list_head sets; struct list_head objects; struct list_head flowtables; - possible_net_t net; u64 hgenerator; u64 handle; u32 use; diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 2d015fcf8d8d..9e20fb759cb8 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -1109,7 +1109,6 @@ static int nf_tables_newtable(struct net *net, struct sock *nlsk, INIT_LIST_HEAD(&table->sets); INIT_LIST_HEAD(&table->objects); INIT_LIST_HEAD(&table->flowtables); - write_pnet(&table->net, net); table->family = family; table->flags = flags; table->handle = ++table_handle; @@ -2824,6 +2823,8 @@ static void nf_tables_rule_destroy(const struct nft_ctx *ctx, static void nf_tables_rule_release(const struct nft_ctx *ctx, struct nft_rule *rule) { + lockdep_commit_lock_is_held(ctx->net); + nft_rule_expr_deactivate(ctx, rule, NFT_TRANS_RELEASE); nf_tables_rule_destroy(ctx, rule); } @@ -4172,6 +4173,8 @@ void nf_tables_deactivate_set(const struct nft_ctx *ctx, struct nft_set *set, struct nft_set_binding *binding, enum nft_trans_phase phase) { + lockdep_commit_lock_is_held(ctx->net); + switch (phase) { case NFT_TRANS_PREPARE_ERROR: nft_set_trans_unbind(ctx, set); @@ -8228,19 +8231,6 @@ static void __nft_release_basechain_now(struct nft_ctx *ctx) nf_tables_chain_destroy(ctx->chain); } -static void nft_release_basechain_rcu(struct rcu_head *head) -{ - struct nft_chain *chain = container_of(head, struct nft_chain, rcu_head); - struct nft_ctx ctx = { - .family = chain->table->family, - .chain = chain, - .net = read_pnet(&chain->table->net), - }; - - __nft_release_basechain_now(&ctx); - put_net(ctx.net); -} - int __nft_release_basechain(struct nft_ctx *ctx) { struct nft_rule *rule; @@ -8255,11 +8245,18 @@ int __nft_release_basechain(struct nft_ctx *ctx) nft_chain_del(ctx->chain); nft_use_dec(&ctx->table->use); - if (maybe_get_net(ctx->net)) - call_rcu(&ctx->chain->rcu_head, nft_release_basechain_rcu); - else + if (!maybe_get_net(ctx->net)) { __nft_release_basechain_now(ctx); + return 0; + } + + /* wait for ruleset dumps to complete. Owning chain is no longer in + * lists, so new dumps can't find any of these rules anymore. + */ + synchronize_rcu(); + __nft_release_basechain_now(ctx); + put_net(ctx->net); return 0; } EXPORT_SYMBOL_GPL(__nft_release_basechain); -- 2.30.2