From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D83ABC43460 for ; Mon, 12 Apr 2021 08:57:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B85CB61366 for ; Mon, 12 Apr 2021 08:57:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238863AbhDLI5z (ORCPT ); Mon, 12 Apr 2021 04:57:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:49038 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238568AbhDLIz5 (ORCPT ); Mon, 12 Apr 2021 04:55:57 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id BA8F161244; Mon, 12 Apr 2021 08:55:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618217739; bh=dp3sJjqaLFb+hTH+4gjTdIJ4GrF/LgqqL1T2O0d3+/s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cOClJBnEtQELAzm3arPRHPWqRdzkhgoXMQhcPuvE+kqfJ8MUgyLzcw5cgqnRHc1p5 PsjHZjO/+ltDrZYJWZl40rQlp3uYOka78UatSa6vqbcLK/gnNt9ECpsOYzMPzX7l2T cmuYfhskZieqMxEF9km68MJSQbEb/PPY8bWsyu/I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Ahmed S. Darwish" , Steffen Klassert , Sasha Levin Subject: [PATCH 5.10 100/188] net: xfrm: Localize sequence counter per network namespace Date: Mon, 12 Apr 2021 10:40:14 +0200 Message-Id: <20210412084016.975473512@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210412084013.643370347@linuxfoundation.org> References: <20210412084013.643370347@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ahmed S. Darwish [ Upstream commit e88add19f68191448427a6e4eb059664650a837f ] A sequence counter write section must be serialized or its internal state can get corrupted. The "xfrm_state_hash_generation" seqcount is global, but its write serialization lock (net->xfrm.xfrm_state_lock) is instantiated per network namespace. The write protection is thus insufficient. To provide full protection, localize the sequence counter per network namespace instead. This should be safe as both the seqcount read and write sections access data exclusively within the network namespace. It also lays the foundation for transforming "xfrm_state_hash_generation" data type from seqcount_t to seqcount_LOCKNAME_t in further commits. Fixes: b65e3d7be06f ("xfrm: state: add sequence count to detect hash resizes") Signed-off-by: Ahmed S. Darwish Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin --- include/net/netns/xfrm.h | 4 +++- net/xfrm/xfrm_state.c | 10 +++++----- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h index 59f45b1e9dac..b59d73d529ba 100644 --- a/include/net/netns/xfrm.h +++ b/include/net/netns/xfrm.h @@ -72,7 +72,9 @@ struct netns_xfrm { #if IS_ENABLED(CONFIG_IPV6) struct dst_ops xfrm6_dst_ops; #endif - spinlock_t xfrm_state_lock; + spinlock_t xfrm_state_lock; + seqcount_t xfrm_state_hash_generation; + spinlock_t xfrm_policy_lock; struct mutex xfrm_cfg_mutex; }; diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 2f1517827995..77499abd9f99 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -44,7 +44,6 @@ static void xfrm_state_gc_task(struct work_struct *work); */ static unsigned int xfrm_state_hashmax __read_mostly = 1 * 1024 * 1024; -static __read_mostly seqcount_t xfrm_state_hash_generation = SEQCNT_ZERO(xfrm_state_hash_generation); static struct kmem_cache *xfrm_state_cache __ro_after_init; static DECLARE_WORK(xfrm_state_gc_work, xfrm_state_gc_task); @@ -140,7 +139,7 @@ static void xfrm_hash_resize(struct work_struct *work) } spin_lock_bh(&net->xfrm.xfrm_state_lock); - write_seqcount_begin(&xfrm_state_hash_generation); + write_seqcount_begin(&net->xfrm.xfrm_state_hash_generation); nhashmask = (nsize / sizeof(struct hlist_head)) - 1U; odst = xfrm_state_deref_prot(net->xfrm.state_bydst, net); @@ -156,7 +155,7 @@ static void xfrm_hash_resize(struct work_struct *work) rcu_assign_pointer(net->xfrm.state_byspi, nspi); net->xfrm.state_hmask = nhashmask; - write_seqcount_end(&xfrm_state_hash_generation); + write_seqcount_end(&net->xfrm.xfrm_state_hash_generation); spin_unlock_bh(&net->xfrm.xfrm_state_lock); osize = (ohashmask + 1) * sizeof(struct hlist_head); @@ -1061,7 +1060,7 @@ xfrm_state_find(const xfrm_address_t *daddr, const xfrm_address_t *saddr, to_put = NULL; - sequence = read_seqcount_begin(&xfrm_state_hash_generation); + sequence = read_seqcount_begin(&net->xfrm.xfrm_state_hash_generation); rcu_read_lock(); h = xfrm_dst_hash(net, daddr, saddr, tmpl->reqid, encap_family); @@ -1174,7 +1173,7 @@ out: if (to_put) xfrm_state_put(to_put); - if (read_seqcount_retry(&xfrm_state_hash_generation, sequence)) { + if (read_seqcount_retry(&net->xfrm.xfrm_state_hash_generation, sequence)) { *err = -EAGAIN; if (x) { xfrm_state_put(x); @@ -2664,6 +2663,7 @@ int __net_init xfrm_state_init(struct net *net) net->xfrm.state_num = 0; INIT_WORK(&net->xfrm.state_hash_work, xfrm_hash_resize); spin_lock_init(&net->xfrm.xfrm_state_lock); + seqcount_init(&net->xfrm.xfrm_state_hash_generation); return 0; out_byspi: -- 2.30.2