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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 autolearn=unavailable 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 A4B84C2D0DB for ; Fri, 24 Jan 2020 14:14:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7A6DA20838 for ; Fri, 24 Jan 2020 14:14:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="IgnQooUn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390182AbgAXOOi (ORCPT ); Fri, 24 Jan 2020 09:14:38 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:56120 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387508AbgAXOOi (ORCPT ); Fri, 24 Jan 2020 09:14:38 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00OED2Q1032309; Fri, 24 Jan 2020 14:14:17 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : mime-version : content-type : in-reply-to; s=corp-2019-08-05; bh=nyerGigvEupFjYOhX0kriAFenR1Pe04fnQVjV9A2T/c=; b=IgnQooUngQQBGu9zsjFhDE5bAlt+fVjCdNAyaXTemzHu3zyApAlonFFM1gyRlZ0YOqpK +Z6dI3WPF8U0iB7l4mHTGqswFgFRKHuEAXOu2HMydncHxmhbkYDSXx3T0VJFkgONO7E9 RbexRXCKghthruFa3/19vfsW5AHBseh/u9uzy5u1xJQuwnXMBcp5E1FDNHNvDl5lvvFx Jf2rOAAWzo251L3ivc/16F6i2VmeeaH6cIJTrDa+ofLQIwtgop5v9HG5RU8dMk6mG6kw NYq4BII8RYhrfiOr3KQSOX96L2enND9lBxd+4xQezLTKSFETYME8UgGbjceF/sr5qs2o yg== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by aserp2120.oracle.com with ESMTP id 2xksyqs6qs-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 24 Jan 2020 14:14:17 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00OE9CB7011673; Fri, 24 Jan 2020 14:14:17 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by aserp3020.oracle.com with ESMTP id 2xqmwfbve8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 24 Jan 2020 14:14:16 +0000 Received: from abhmp0006.oracle.com (abhmp0006.oracle.com [141.146.116.12]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 00OEE8s5001970; Fri, 24 Jan 2020 14:14:08 GMT Received: from kili.mountain (/129.205.23.165) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 24 Jan 2020 06:14:07 -0800 Date: Fri, 24 Jan 2020 17:13:56 +0300 From: Dan Carpenter To: Hans Verkuil , syzbot , Hillf Danton Cc: Alan Stern , Allison Randal , Greg Kroah-Hartman , Souptick Joarder , andreyknvl@google.com, bnvandana@gmail.com, laurent.pinchart@ideasonboard.com, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-usb@vger.kernel.org, mchehab@kernel.org, syzkaller-bugs@googlegroups.com Subject: [PATCH] media: usbvision: Fix a use after free in v4l2_release() Message-ID: <20200124141356.365bgzg2lp3tjedm@kili.mountain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200123102707.2596-1-hdanton@sina.com> X-Mailer: git-send-email haha only kidding User-Agent: NeoMutt/20170113 (1.7.2) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9509 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001240118 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9509 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001240119 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Syzbot triggered a use after free in v5.5-rc6: BUG: KASAN: use-after-free in v4l2_release+0x2f1/0x390 drivers/media/v4l2-core/v4l2-dev.c:459 Allocated by task 94: usbvision_alloc drivers/media/usb/usbvision/usbvision-video.c:1315 [inline] usbvision_probe.cold+0x5c5/0x1f21 drivers/media/usb/usbvision/usbvision-video.c:1469 Freed by task 1913: kfree+0xd5/0x300 mm/slub.c:3957 usbvision_release+0x181/0x1c0 drivers/media/usb/usbvision/usbvision-video.c:1364 usbvision_radio_close.cold+0x2b/0x74 drivers/media/usb/usbvision/usbvision-video.c:1130 v4l2_release+0x2e7/0x390 drivers/media/v4l2-core/v4l2-dev.c:455 The problem is that the v4l2_release() calls usbvision_release() which frees "usbvision" but v4l2_release() still wants to use "usbvision->vdev". One solution is to make this devm_ allocated memory so the memory isn't freed until later. Reported-by: syzbot+75287f75e2fedd69d680@syzkaller.appspotmail.com Signed-off-by: Dan Carpenter --- I copied this idea from a different driver, but I haven't tested it. I wanted to try the #syz fix command to see if it works. drivers/media/usb/usbvision/usbvision-video.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/media/usb/usbvision/usbvision-video.c b/drivers/media/usb/usbvision/usbvision-video.c index 93d36aab824f..07b4763062c4 100644 --- a/drivers/media/usb/usbvision/usbvision-video.c +++ b/drivers/media/usb/usbvision/usbvision-video.c @@ -1312,7 +1312,7 @@ static struct usb_usbvision *usbvision_alloc(struct usb_device *dev, { struct usb_usbvision *usbvision; - usbvision = kzalloc(sizeof(*usbvision), GFP_KERNEL); + usbvision = devm_kzalloc(&dev->dev, sizeof(*usbvision), GFP_KERNEL); if (!usbvision) return NULL; @@ -1336,7 +1336,6 @@ static struct usb_usbvision *usbvision_alloc(struct usb_device *dev, v4l2_ctrl_handler_free(&usbvision->hdl); v4l2_device_unregister(&usbvision->v4l2_dev); err_free: - kfree(usbvision); return NULL; } @@ -1361,7 +1360,6 @@ static void usbvision_release(struct usb_usbvision *usbvision) v4l2_ctrl_handler_free(&usbvision->hdl); v4l2_device_unregister(&usbvision->v4l2_dev); - kfree(usbvision); PDEBUG(DBG_PROBE, "success"); } -- 2.11.0