From patchwork Thu Oct 7 05:55:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steffen Klassert X-Patchwork-Id: 12540953 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E4971C433FE for ; Thu, 7 Oct 2021 05:55:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C182761245 for ; Thu, 7 Oct 2021 05:55:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240129AbhJGF52 (ORCPT ); Thu, 7 Oct 2021 01:57:28 -0400 Received: from a.mx.secunet.com ([62.96.220.36]:37692 "EHLO a.mx.secunet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232427AbhJGF5W (ORCPT ); Thu, 7 Oct 2021 01:57:22 -0400 Received: from localhost (localhost [127.0.0.1]) by a.mx.secunet.com (Postfix) with ESMTP id 00CB72056D; Thu, 7 Oct 2021 07:55:29 +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 9JZP_A_P2vyw; Thu, 7 Oct 2021 07:55:28 +0200 (CEST) Received: from mailout1.secunet.com (mailout1.secunet.com [62.96.220.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by a.mx.secunet.com (Postfix) with ESMTPS id DDAC720539; Thu, 7 Oct 2021 07:55:27 +0200 (CEST) Received: from cas-essen-02.secunet.de (unknown [10.53.40.202]) by mailout1.secunet.com (Postfix) with ESMTP id CF3D080004A; Thu, 7 Oct 2021 07:55:27 +0200 (CEST) Received: from mbx-essen-01.secunet.de (10.53.40.197) by cas-essen-02.secunet.de (10.53.40.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.14; Thu, 7 Oct 2021 07:55:27 +0200 Received: from gauss2.secunet.de (10.182.7.193) by mbx-essen-01.secunet.de (10.53.40.197) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.14; Thu, 7 Oct 2021 07:55:26 +0200 Received: by gauss2.secunet.de (Postfix, from userid 1000) id 9F69A318010D; Thu, 7 Oct 2021 07:55:26 +0200 (CEST) From: Steffen Klassert To: David Miller , Jakub Kicinski CC: Herbert Xu , Steffen Klassert , Subject: [PATCH 1/5] net: xfrm: fix shift-out-of-bounds in xfrm_get_default Date: Thu, 7 Oct 2021 07:55:20 +0200 Message-ID: <20211007055524.319785-2-steffen.klassert@secunet.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211007055524.319785-1-steffen.klassert@secunet.com> References: <20211007055524.319785-1-steffen.klassert@secunet.com> MIME-Version: 1.0 X-ClientProxiedBy: cas-essen-01.secunet.de (10.53.40.201) To mbx-essen-01.secunet.de (10.53.40.197) X-EXCLAIMER-MD-CONFIG: 2c86f778-e09b-4440-8b15-867914633a10 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Pavel Skripkin Syzbot hit shift-out-of-bounds in xfrm_get_default. The problem was in missing validation check for user data. up->dirmask comes from user-space, so we need to check if this value is less than XFRM_USERPOLICY_DIRMASK_MAX to avoid shift-out-of-bounds bugs. Fixes: 2d151d39073a ("xfrm: Add possibility to set the default to block if we have no policy") Reported-and-tested-by: syzbot+b2be9dd8ca6f6c73ee2d@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_user.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 03b66d154b2b..4719a6d54aa6 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -2005,6 +2005,11 @@ static int xfrm_get_default(struct sk_buff *skb, struct nlmsghdr *nlh, return -EMSGSIZE; } + if (up->dirmask >= XFRM_USERPOLICY_DIRMASK_MAX) { + kfree_skb(r_skb); + return -EINVAL; + } + r_up = nlmsg_data(r_nlh); r_up->action = ((net->xfrm.policy_default & (1 << up->dirmask)) >> up->dirmask);