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 4FDBFC2D0E7 for ; Fri, 27 Mar 2020 08:10:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 308B720714 for ; Fri, 27 Mar 2020 08:10:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727247AbgC0IKV (ORCPT ); Fri, 27 Mar 2020 04:10:21 -0400 Received: from a.mx.secunet.com ([62.96.220.36]:54992 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726959AbgC0IKT (ORCPT ); Fri, 27 Mar 2020 04:10:19 -0400 Received: from localhost (localhost [127.0.0.1]) by a.mx.secunet.com (Postfix) with ESMTP id 77C2020501; Fri, 27 Mar 2020 09:10:18 +0100 (CET) X-Virus-Scanned: by secunet Received: from a.mx.secunet.com ([127.0.0.1]) by localhost (a.mx.secunet.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Waw8fO_v1M-W; Fri, 27 Mar 2020 09:10:16 +0100 (CET) Received: from mail-essen-01.secunet.de (mail-essen-01.secunet.de [10.53.40.204]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by a.mx.secunet.com (Postfix) with ESMTPS id 8C0C720536; Fri, 27 Mar 2020 09:10:14 +0100 (CET) Received: from mbx-dresden-01.secunet.de (10.53.40.199) by MAIL-ESSEN-01.secunet.de (10.53.40.204) with Microsoft SMTP Server (TLS) id 14.3.487.0; Fri, 27 Mar 2020 09:10:14 +0100 Received: from gauss2.secunet.de (10.182.7.193) by mbx-dresden-01.secunet.de (10.53.40.199) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 27 Mar 2020 09:10:13 +0100 Received: by gauss2.secunet.de (Postfix, from userid 1000) id 33B2F318037B; Fri, 27 Mar 2020 09:10:13 +0100 (CET) From: Steffen Klassert To: David Miller CC: Herbert Xu , Steffen Klassert , Subject: [PATCH 8/8] xfrm: policy: Fix doulbe free in xfrm_policy_timer Date: Fri, 27 Mar 2020 09:10:07 +0100 Message-ID: <20200327081007.1185-9-steffen.klassert@secunet.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200327081007.1185-1-steffen.klassert@secunet.com> References: <20200327081007.1185-1-steffen.klassert@secunet.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: cas-essen-01.secunet.de (10.53.40.201) To mbx-dresden-01.secunet.de (10.53.40.199) X-EXCLAIMER-MD-CONFIG: 2c86f778-e09b-4440-8b15-867914633a10 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: YueHaibing After xfrm_add_policy add a policy, its ref is 2, then xfrm_policy_timer read_lock xp->walk.dead is 0 .... mod_timer() xfrm_policy_kill policy->walk.dead = 1 .... del_timer(&policy->timer) xfrm_pol_put //ref is 1 xfrm_pol_put //ref is 0 xfrm_policy_destroy call_rcu xfrm_pol_hold //ref is 1 read_unlock xfrm_pol_put //ref is 0 xfrm_policy_destroy call_rcu xfrm_policy_destroy is called twice, which may leads to double free. Call Trace: RIP: 0010:refcount_warn_saturate+0x161/0x210 ... xfrm_policy_timer+0x522/0x600 call_timer_fn+0x1b3/0x5e0 ? __xfrm_decode_session+0x2990/0x2990 ? msleep+0xb0/0xb0 ? _raw_spin_unlock_irq+0x24/0x40 ? __xfrm_decode_session+0x2990/0x2990 ? __xfrm_decode_session+0x2990/0x2990 run_timer_softirq+0x5c5/0x10e0 Fix this by use write_lock_bh in xfrm_policy_kill. Fixes: ea2dea9dacc2 ("xfrm: remove policy lock when accessing policy->walk.dead") Signed-off-by: YueHaibing Acked-by: Timo Teräs Acked-by: Herbert Xu Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_policy.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 297d1eb79e5c..96a8c452b63e 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -434,7 +434,9 @@ EXPORT_SYMBOL(xfrm_policy_destroy); static void xfrm_policy_kill(struct xfrm_policy *policy) { + write_lock_bh(&policy->lock); policy->walk.dead = 1; + write_unlock_bh(&policy->lock); atomic_inc(&policy->genid); -- 2.17.1