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=-8.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 955B3C3A5A1 for ; Thu, 22 Aug 2019 15:00:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5B8042133F for ; Thu, 22 Aug 2019 15:00:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=web.de header.i=@web.de header.b="DeGTzMvs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389344AbfHVPA4 (ORCPT ); Thu, 22 Aug 2019 11:00:56 -0400 Received: from mout.web.de ([212.227.17.12]:43209 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725886AbfHVPA4 (ORCPT ); Thu, 22 Aug 2019 11:00:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1566485699; bh=eQcMl+avN3kIGGjB3h5pSL5Jp/iss5fD7c3NsD0te/A=; h=X-UI-Sender-Class:Subject:From:To:Cc:References:Date:In-Reply-To; b=DeGTzMvsX/JvLHOCiLwrrjeocg8CgDi1Zh08eA0JaVL72hh0DJ0nfkJi+v4JHjASv 3prpr62k4w4DgZpww8iSVqC0CB3CbDoxrAQMKTV54pvI+evPrykGdJ6Qa4t8lt/YGa P22aG1OP6EEL+1OWGttmcQThXULSuEJI5BHtaJ/U= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [192.168.1.2] ([78.49.181.43]) by smtp.web.de (mrweb102 [213.165.67.124]) with ESMTPSA (Nemesis) id 0M4ZTk-1iAeD83J6q-00yeHS; Thu, 22 Aug 2019 16:54:58 +0200 Subject: [PATCH 2/2] ipc/mqueue: Improve exception handling in do_mq_notify() From: Markus Elfring To: kernel-janitors@vger.kernel.org, Al Viro , Andrew Morton , Arnd Bergmann , David Howells , Davidlohr Bueso , Kees Cook , Li Rongqing Cc: LKML References: <6e9378d1-3b9b-e138-53f6-bc5683ac8b8c@web.de> Openpgp: preference=signencrypt Autocrypt: addr=Markus.Elfring@web.de; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <6e9378d1-3b9b-e138-53f6-bc5683ac8b8c@web.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:nihP1aXNcItu2XmdTNy2sYhpRwgN6spV+s1mfBOGQqQ6ee7b1v+ g7UHRlM6M/g4QG5Aen/rExoklC7oU0A4UDGCqqlSHwrtxFmz0MULnswpoIJEnwy+md8WQAc jIT8lx3jAUc+n3JnYNvlzy/+qEMOd3K4Ip/4ffK+AMXSxXm+4fqSw+nV12iOY715Lo2srKH SGwjF1DjPgsEZZZY6/UGQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:jpFVYdL4I0c=:OYor+BDZoYyK8cDVBopyUk kxHeMe+5g/bP4NJz4B1ZLYNlCKEluHJyxGtI8L9VybEME9zjwB46i8IV7mN/H7VGGX9wcW+wC 73d3WuitvYHNPCUmn4YPRcjRNlFJJAAqUXwz/ZLhkAMUIGjsPwJDZgeE4zz8steQPQCYvJcat WzA7oTshh4uaDXuFL/YMpuc/KX3VvHTQ16eEB9X5G3ph/VEdtsMrXNRj41OX5THkFDxpEIpk/ kw+hUaHNcvZqOE9F9VvGbOW8BFH+s0brO0fYROhHH1kjBUQtdA2yjzrhmXVAG6s8HUhbnpyyk 9q1l5TbzTHyZ3S4+LuUn+0S4R8Y59eG0BtdvTksDHXSrbFGvt6ZTMiJozp/EsZaBFc2VL0NK6 2gfocTxTI1rqegFZhnYhBKE1s/gWvX8r/t0N5kayvgXH1enSn6LaVFiMWn047FWgxmbfY7MRL W54muRI9GGzdn6ri6zi9PsAX5pTSek+KWHPh9f1WgLziQYNBZdieSNR4k6phOU3dszLcAngqE tqsiLDjzUWgHZ/OOyAAF/3432G2Yd+r9HMD7i7KQ98fdvAwkJZhr0NvJhcJlRN+HFmygusWqN oH2FzKxLNRaX/LlRxqhWS9GDeDw2yX9o8g9kUEyKDXJ9em0IopU8+c0NdaviSVJzkSSvzz7K+ NKyhi7dkREsmutgGbjn3sx0l0QGdVNRLVjNfwRs0UXzRUW2A4CO/SVJrGd44ssXfyN7dLKc9s s4RH6EOQDz2sWaFCNWkg6I8ioRK3ZNkKW0n3aPrhg6k3MEzjm7cmEznyAWzyF+V1AGZmdeY1G vAXDfXwaiXQTqfpb7AVkZJfZQBbTfHGkKuZeYpbxfKf72zk7fxdsk6WyT4DPy3DdJvsDrHGQt AbimASSIs7//sQoAmfY/B9ir50PA6ddMz56gKpHXGy8IG5HQ7WhmpDnWjzIV1jVdKGjvPijEr +SdMyxryz3N3hoJ7i+h95iipYYP7bRLWjGDhIdfacOqMsml6bCnji/fobaN4YvYAzUPNey647 9mp3IWvtZpGZw6/e/ECnBSVcjgWQQlMDmUwtta9mvyQZCE5pjy00lPdRuXinGv4m1RWRFsQ9T aSCDFUt9GabfepvFbZV/q1grQQmC7/a/vAUgrvQMg/74LhurHKk9msTY+RAgUh5c2a5lAzx0o IvjYI= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Markus Elfring Date: Thu, 22 Aug 2019 16:21:17 +0200 Null pointers were assigned to local variables in a few cases as exception handling. The jump target =E2=80=9Cout=E2=80=9D was used wher= e no meaningful data processing actions should eventually be performed by branches of an if statement then. Use an additional jump target for calling dev_kfree_skb() directly. Return also directly after error conditions were detected when no extra clean-up is needed by this function implementation. Signed-off-by: Markus Elfring =2D-- ipc/mqueue.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 494ab78863f4..ad6c475eb370 100644 =2D-- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -1241,15 +1241,14 @@ static int do_mq_notify(mqd_t mqdes, const struct = sigevent *notification) /* create the notify skb */ nc =3D alloc_skb(NOTIFY_COOKIE_LEN, GFP_KERNEL); - if (!nc) { - ret =3D -ENOMEM; - goto out; - } + if (!nc) + return -ENOMEM; + if (copy_from_user(nc->data, notification->sigev_value.sival_ptr, NOTIFY_COOKIE_LEN)) { ret =3D -EFAULT; - goto out; + goto free_skb; } /* TODO: add a header? */ @@ -1265,8 +1264,7 @@ static int do_mq_notify(mqd_t mqdes, const struct si= gevent *notification) fdput(f); if (IS_ERR(sock)) { ret =3D PTR_ERR(sock); - sock =3D NULL; - goto out; + goto free_skb; } timeo =3D MAX_SCHEDULE_TIMEOUT; @@ -1275,11 +1273,8 @@ static int do_mq_notify(mqd_t mqdes, const struct s= igevent *notification) sock =3D NULL; goto retry; } - if (ret) { - sock =3D NULL; - nc =3D NULL; - goto out; - } + if (ret) + return ret; } } @@ -1335,6 +1330,7 @@ static int do_mq_notify(mqd_t mqdes, const struct si= gevent *notification) if (sock) netlink_detachskb(sock, nc); else +free_skb: dev_kfree_skb(nc); return ret; =2D- 2.23.0