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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 D909BC4BA32 for ; Wed, 26 Feb 2020 22:55:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B5A8F2072D for ; Wed, 26 Feb 2020 22:55:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727940AbgBZWzG (ORCPT ); Wed, 26 Feb 2020 17:55:06 -0500 Received: from correo.us.es ([193.147.175.20]:36442 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727902AbgBZWzC (ORCPT ); Wed, 26 Feb 2020 17:55:02 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 09B221C4385 for ; Wed, 26 Feb 2020 23:54:53 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id ED811DA3A0 for ; Wed, 26 Feb 2020 23:54:52 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id E2D14DA38F; Wed, 26 Feb 2020 23:54:52 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 186A8DA788; Wed, 26 Feb 2020 23:54:51 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Wed, 26 Feb 2020 23:54:51 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from salvia.here (unknown [90.77.255.23]) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPA id E6F0942EF4E0; Wed, 26 Feb 2020 23:54:50 +0100 (CET) X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org Subject: [PATCH 6/6] netfilter: xt_hashlimit: unregister proc file before releasing mutex Date: Wed, 26 Feb 2020 23:54:42 +0100 Message-Id: <20200226225442.9598-7-pablo@netfilter.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20200226225442.9598-1-pablo@netfilter.org> References: <20200226225442.9598-1-pablo@netfilter.org> X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Cong Wang Before releasing the global mutex, we only unlink the hashtable from the hash list, its proc file is still not unregistered at this point. So syzbot could trigger a race condition where a parallel htable_create() could register the same file immediately after the mutex is released. Move htable_remove_proc_entry() back to mutex protection to fix this. And, fold htable_destroy() into htable_put() to make the code slightly easier to understand. Reported-and-tested-by: syzbot+d195fd3b9a364ddd6731@syzkaller.appspotmail.com Fixes: c4a3922d2d20 ("netfilter: xt_hashlimit: reduce hashlimit_mutex scope for htable_put()") Signed-off-by: Cong Wang Signed-off-by: Pablo Neira Ayuso --- net/netfilter/xt_hashlimit.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c index 7a2c4b8408c4..8c835ad63729 100644 --- a/net/netfilter/xt_hashlimit.c +++ b/net/netfilter/xt_hashlimit.c @@ -402,15 +402,6 @@ static void htable_remove_proc_entry(struct xt_hashlimit_htable *hinfo) remove_proc_entry(hinfo->name, parent); } -static void htable_destroy(struct xt_hashlimit_htable *hinfo) -{ - cancel_delayed_work_sync(&hinfo->gc_work); - htable_remove_proc_entry(hinfo); - htable_selective_cleanup(hinfo, true); - kfree(hinfo->name); - vfree(hinfo); -} - static struct xt_hashlimit_htable *htable_find_get(struct net *net, const char *name, u_int8_t family) @@ -432,8 +423,13 @@ static void htable_put(struct xt_hashlimit_htable *hinfo) { if (refcount_dec_and_mutex_lock(&hinfo->use, &hashlimit_mutex)) { hlist_del(&hinfo->node); + htable_remove_proc_entry(hinfo); mutex_unlock(&hashlimit_mutex); - htable_destroy(hinfo); + + cancel_delayed_work_sync(&hinfo->gc_work); + htable_selective_cleanup(hinfo, true); + kfree(hinfo->name); + vfree(hinfo); } } -- 2.11.0