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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D23D9C7618B for ; Fri, 26 Jul 2019 09:45:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB03C22CED for ; Fri, 26 Jul 2019 09:45:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726320AbfGZJpr (ORCPT ); Fri, 26 Jul 2019 05:45:47 -0400 Received: from a.mx.secunet.com ([62.96.220.36]:32956 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725842AbfGZJpq (ORCPT ); Fri, 26 Jul 2019 05:45:46 -0400 Received: from localhost (localhost [127.0.0.1]) by a.mx.secunet.com (Postfix) with ESMTP id C392A20268; Fri, 26 Jul 2019 11:45:44 +0200 (CEST) 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 lEmaeQYyVd6U; Fri, 26 Jul 2019 11:45:14 +0200 (CEST) Received: from mail-essen-01.secunet.de (mail-essen-01.secunet.de [10.53.40.204]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by a.mx.secunet.com (Postfix) with ESMTPS id 897FB201E1; Fri, 26 Jul 2019 11:45:14 +0200 (CEST) Received: from gauss2.secunet.de (10.182.7.193) by mail-essen-01.secunet.de (10.53.40.204) with Microsoft SMTP Server id 14.3.468.0; Fri, 26 Jul 2019 11:45:14 +0200 Received: by gauss2.secunet.de (Postfix, from userid 1000) id 31D303180409; Fri, 26 Jul 2019 11:45:14 +0200 (CEST) Date: Fri, 26 Jul 2019 11:45:14 +0200 From: Steffen Klassert To: Jia-Ju Bai CC: , , , Subject: Re: [PATCH] net: key: af_key: Fix possible null-pointer dereferences in pfkey_send_policy_notify() Message-ID: <20190726094514.GD14601@gauss3.secunet.de> References: <20190724093509.1676-1-baijiaju1990@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20190724093509.1676-1-baijiaju1990@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-EXCLAIMER-MD-CONFIG: 2c86f778-e09b-4440-8b15-867914633a10 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 24, 2019 at 05:35:09PM +0800, Jia-Ju Bai wrote: > In pfkey_send_policy_notify(), there is an if statement on line 3081 to > check whether xp is NULL: > if (xp && xp->type != XFRM_POLICY_TYPE_MAIN) > > When xp is NULL, it is used by key_notify_policy() on line 3090: > key_notify_policy(xp, ...) > pfkey_xfrm_policy2msg_prep(xp) -- line 2211 > pfkey_xfrm_policy2msg_size(xp) -- line 2046 > for (i=0; ixfrm_nr; i++) -- line 2026 > t = xp->xfrm_vec + i; -- line 2027 > key_notify_policy(xp, ...) > xp_net(xp) -- line 2231 > return read_pnet(&xp->xp_net); -- line 534 Please don't quote random code lines, explain the problem instead. > > Thus, possible null-pointer dereferences may occur. > > To fix these bugs, xp is checked before calling key_notify_policy(). > > These bugs are found by a static analysis tool STCheck written by us. > > Signed-off-by: Jia-Ju Bai > --- > net/key/af_key.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/net/key/af_key.c b/net/key/af_key.c > index b67ed3a8486c..ced54144d5fd 100644 > --- a/net/key/af_key.c > +++ b/net/key/af_key.c > @@ -3087,6 +3087,8 @@ static int pfkey_send_policy_notify(struct xfrm_policy *xp, int dir, const struc > case XFRM_MSG_DELPOLICY: > case XFRM_MSG_NEWPOLICY: > case XFRM_MSG_UPDPOLICY: > + if (!xp) > + break; I think this can not happen. Who sends one of these notifications without a pointer to the policy?