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=-7.0 required=3.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 9CFADC61CE4 for ; Sun, 20 Jan 2019 09:58:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6BAA92084C for ; Sun, 20 Jan 2019 09:58:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730413AbfATJ6q (ORCPT ); Sun, 20 Jan 2019 04:58:46 -0500 Received: from shiva144.upmc.fr ([134.157.0.144]:45594 "EHLO shiva144.upmc.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726939AbfATJ6q (ORCPT ); Sun, 20 Jan 2019 04:58:46 -0500 Received: from shiva144.upmc.fr (localhost [127.0.0.1]) by shiva144.upmc.fr (Postfix) with ESMTP id 3000D61723; Sun, 20 Jan 2019 10:58:43 +0100 (CET) Received: from courriel.upmc.fr (courriel4.reseau.jussieu.fr [134.157.0.195]) by shiva144.upmc.fr (Postfix) with ESMTP id 6122F616EE; Sun, 20 Jan 2019 10:58:28 +0100 (CET) X-CIds: courriel4 Received: from [192.168.0.10] (lfbn-1-499-146.w86-245.abo.wanadoo.fr [86.245.202.146]) (authentified, mech=PLAIN) by courriel.upmc.fr (8.14.5/jtpda-5.5pre1) with ESMTP id x0K9wQMZ086596 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO) ; Sun, 20 Jan 2019 10:58:27 +0100 (CET) (envelope-from f6bvp@free.fr) Subject: Re: [PATCH] NET:AX25:ROSE NULL ax25_cb kernel panic Cc: linux-hams , Ralf Baechle , David Miller , Linux Netdev List , n1uro@n1uro.ampr.org, C Schuman References: <57ADC4F4.6080707@free.fr> <19a0a879-8a8d-4c84-5de9-5ce222377fcb@free.fr> From: f6bvp Openpgp: preference=signencrypt Autocrypt: addr=f6bvp@free.fr; prefer-encrypt=mutual; keydata= mQENBFJj8/4BCADRBgzyjFzY0Ww4PzVAc5xLHFOGubRwf4zmACzqarMx8SfUt+xfg8Jme+9A DBsrrrOfaPLZ7gZtGzqrXMkP353ZhmbzxwbdtLruQyr+NxLp7p4oLHGZ4bNQ7gwrofHZU1XM q4ScT1scwI2eapRZ1zYDQsUI6QSOr1pnWmPhDlcCLZGpUu2EmD5D9IYS8Xm6B5wQYhqdHziK 1zNgIPkLWTIVROgLM2pLqwU0Z8M+8TxChuZalZr6RPbWHWLf/ozSifjjj3ECUHPOSbceISK6 BfZP9lae4K5x38qRgDyJquYanxGHTKnX1V4YPdpaSkqAjPA13o3Cs5bBqk+WMGGmMamdABEB AAG0J0Jlcm5hcmQgUGlkb3V4IDxiZXJuYXJkLnBpZG91eEBmcmVlLmZyPokBPwQTAQIAKQUC UmPz/gIbIwUJCWYBgAcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEHlsvAVLvLtMYU8H /2xK4WqjSeIhm9spVAt2XCUbOIftTWZWayaonEeEMSTTMYMtmKn6jN9tN1SWdlaZNwBeM64Z LSAoDo2VEgx0UOg5N0ETv1GzVHACrcClGez0AGWK+CdMknVLRc0A9pnf8+Uk93IDOTemWrUO aaGr1vGo4hUDBZobxdri9ibARE4mpb8vcbkacvZZOxcI3/ZHhYaHLO9GK/ptF6cGu9RWZymz fGLD+DyQ0lyVCVakhEbfMSePRVIofBJZhVEb/LtQ4tw0SioPtRB6muTNldbB3wXfg5yFHo9n kcf36ZpTOThgO0mgB6b5F+jxne+j8Tb4Rx8s0MQlcOzHX4QZBB3wrSk= To: Dmitry Vyukov Message-ID: <9802433c-7f50-160f-5246-8e9e2cfb571b@free.fr> Date: Sun, 20 Jan 2019 10:58:32 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <19a0a879-8a8d-4c84-5de9-5ce222377fcb@free.fr> Content-Type: text/plain; charset=utf-8 Content-Language: fr Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV using ClamSMTP Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi, Dmitry wrote: >Please also add: >Reported-by: syzbot+1a2c456a1ea08fa5b5f7@syzkaller.appspotmail.com I did mention syzbot report but without the exact reference, thanks. >It's this report we are fixing, right? >https://syzkaller.appspot.com/bug?id=fd0b0b00fc26abb4b35663a0e2f1c91d8e6e5725 Yes exactly ! This is a long date well know bug I reported two years ago. Bernard On Sat, Jan 19, 2019 at 11:58 AM f6bvp wrote: > > > [PATCH] [ROSE] NULL ax25_cb kernel panic > > When an internally generated frame is handled by rose_xmit(), > rose_route_frame() is called: > > if (!rose_route_frame(skb, NULL)) { > dev_kfree_skb(skb); > stats->tx_errors++; > return NETDEV_TX_OK; > } > > We have the same code sequence in Net/Rom where an internally generated > frame is handled by nr_xmit() calling nr_route_frame(skb, NULL). > However, in this function NULL argument is tested while it is not in > rose_route_frame(). > Then kernel panic occurs later on when calling ax25cmp() with a NULL > ax25_cb argument as reported many times and recently with syzbot. > > We need to test if ax25 is NULL before using it. > > Here is the patch: > > diff --git a/net/rose/rose_route.c b/net/rose/rose_route.c > index 77e9f85a2c92..7f075255a372 100644 > --- a/net/rose/rose_route.c > +++ b/net/rose/rose_route.c > @@ -850,6 +850,7 @@ void rose_link_device_down(struct net_device *dev) > > /* > * Route a frame to an appropriate AX.25 connection. > + * a NULL ax25_cb indicates an internally generated frame. > */ > int rose_route_frame(struct sk_buff *skb, ax25_cb *ax25) > { > @@ -867,6 +868,10 @@ int rose_route_frame(struct sk_buff *skb, ax25_cb > *ax25) > > if (skb->len < ROSE_MIN_LEN) > return res; > + > + if (!ax25) > + return rose_loopback_queue(skb, NULL); > + > frametype = skb->data[2]; > lci = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF); > if (frametype == ROSE_CALL_REQUEST && > > Signed-off-by: Bernard Pidoux, f6bvp Please also add: Reported-by: syzbot+1a2c456a1ea08fa5b5f7@syzkaller.appspotmail.com It's this report we are fixing, right? https://syzkaller.appspot.com/bug?id=fd0b0b00fc26abb4b35663a0e2f1c91d8e6e5725