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=-19.5 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, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 6D318C43216 for ; Mon, 26 Jul 2021 15:58:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 568EE6056C for ; Mon, 26 Jul 2021 15:58:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235848AbhGZPSX (ORCPT ); Mon, 26 Jul 2021 11:18:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:50732 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237039AbhGZPKL (ORCPT ); Mon, 26 Jul 2021 11:10:11 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8DE456056C; Mon, 26 Jul 2021 15:50:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1627314640; bh=Qw19aLmwjbQ/wEhpzwi7cscgJrpLdQ4eDTm33qriIX0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CnPCY7D0NWk9rnjlh6b7ezPlRHeRmM7ZJtLD31y9OsHyrucRNtEXLEfXaGZoRTwzZ r4eymg9xvcddVciJv0HwrOs+Vc9VtOJ4xKhBJSwnRXUemedtAhxVSLczeqawpJ3iUo jDuX5cqjcC//ogXoRZaFLRpVCdLT4cR6N3VfLUg4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vasily Averin , Florian Westphal , Pablo Neira Ayuso Subject: [PATCH 4.19 039/120] netfilter: ctnetlink: suspicious RCU usage in ctnetlink_dump_helpinfo Date: Mon, 26 Jul 2021 17:38:11 +0200 Message-Id: <20210726153833.649863937@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210726153832.339431936@linuxfoundation.org> References: <20210726153832.339431936@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: linux-kernel@vger.kernel.org From: Vasily Averin commit c23a9fd209bc6f8c1fa6ee303fdf037d784a1627 upstream. Two patches listed below removed ctnetlink_dump_helpinfo call from under rcu_read_lock. Now its rcu_dereference generates following warning: ============================= WARNING: suspicious RCU usage 5.13.0+ #5 Not tainted ----------------------------- net/netfilter/nf_conntrack_netlink.c:221 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 stack backtrace: CPU: 1 PID: 2251 Comm: conntrack Not tainted 5.13.0+ #5 Call Trace: dump_stack+0x7f/0xa1 ctnetlink_dump_helpinfo+0x134/0x150 [nf_conntrack_netlink] ctnetlink_fill_info+0x2c2/0x390 [nf_conntrack_netlink] ctnetlink_dump_table+0x13f/0x370 [nf_conntrack_netlink] netlink_dump+0x10c/0x370 __netlink_dump_start+0x1a7/0x260 ctnetlink_get_conntrack+0x1e5/0x250 [nf_conntrack_netlink] nfnetlink_rcv_msg+0x613/0x993 [nfnetlink] netlink_rcv_skb+0x50/0x100 nfnetlink_rcv+0x55/0x120 [nfnetlink] netlink_unicast+0x181/0x260 netlink_sendmsg+0x23f/0x460 sock_sendmsg+0x5b/0x60 __sys_sendto+0xf1/0x160 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x36/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: 49ca022bccc5 ("netfilter: ctnetlink: don't dump ct extensions of unconfirmed conntracks") Fixes: 0b35f6031a00 ("netfilter: Remove duplicated rcu_read_lock.") Signed-off-by: Vasily Averin Reviewed-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nf_conntrack_netlink.c | 3 +++ 1 file changed, 3 insertions(+) --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -213,6 +213,7 @@ static int ctnetlink_dump_helpinfo(struc if (!help) return 0; + rcu_read_lock(); helper = rcu_dereference(help->helper); if (!helper) goto out; @@ -228,9 +229,11 @@ static int ctnetlink_dump_helpinfo(struc nla_nest_end(skb, nest_helper); out: + rcu_read_unlock(); return 0; nla_put_failure: + rcu_read_unlock(); return -1; }