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 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 7B706C61CE4 for ; Sat, 19 Jan 2019 11:04:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 531312084C for ; Sat, 19 Jan 2019 11:04:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727861AbfASLEX (ORCPT ); Sat, 19 Jan 2019 06:04:23 -0500 Received: from shiva144.upmc.fr ([134.157.0.144]:37398 "EHLO shiva144.upmc.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727790AbfASLEW (ORCPT ); Sat, 19 Jan 2019 06:04:22 -0500 X-Greylist: delayed 347 seconds by postgrey-1.27 at vger.kernel.org; Sat, 19 Jan 2019 06:04:21 EST Received: from shiva144.upmc.fr (localhost [127.0.0.1]) by shiva144.upmc.fr (Postfix) with ESMTP id 09D09616FD; Sat, 19 Jan 2019 11:58:33 +0100 (CET) Received: from courriel.upmc.fr (courriel3.reseau.jussieu.fr [134.157.0.194]) by shiva144.upmc.fr (Postfix) with ESMTP id EF581615F5; Sat, 19 Jan 2019 11:58:32 +0100 (CET) X-CIds: courriel3 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 x0JAwTIE061471 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO) ; Sat, 19 Jan 2019 11:58:32 +0100 (CET) (envelope-from f6bvp@free.fr) Subject: [PATCH] NET:AX25:ROSE NULL ax25_cb kernel panic From: f6bvp To: linux-hams Cc: Ralf Baechle , Dmitry Vyukov , David Miller , Linux Netdev List , F6BVP , brian@support.uroweb.net References: <57ADC4F4.6080707@free.fr> 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= Message-ID: <19a0a879-8a8d-4c84-5de9-5ce222377fcb@free.fr> Date: Sat, 19 Jan 2019 11:58:35 +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: <57ADC4F4.6080707@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 [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