From patchwork Wed Jan 20 10:20:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takashi Iwai X-Patchwork-Id: 12031925 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 9A886C433DB for ; Wed, 20 Jan 2021 10:45:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7451D23339 for ; Wed, 20 Jan 2021 10:45:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387717AbhATKmg (ORCPT ); Wed, 20 Jan 2021 05:42:36 -0500 Received: from mx2.suse.de ([195.135.220.15]:56376 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732967AbhATKVn (ORCPT ); Wed, 20 Jan 2021 05:21:43 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id AE908AFB4; Wed, 20 Jan 2021 10:21:00 +0000 (UTC) From: Takashi Iwai To: Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Stefan Seyfried Subject: [PATCH 2/2] media: dvb-usb: Fix use-after-free access Date: Wed, 20 Jan 2021 11:20:57 +0100 Message-Id: <20210120102057.21143-3-tiwai@suse.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210120102057.21143-1-tiwai@suse.de> References: <20210120102057.21143-1-tiwai@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org dvb_usb_device_init() copies the properties to the own data, so that the callers can release the original properties later (as done in the commit 299c7007e936 "media: dw2102: Fix memleak on sequence of probes"). However, it also stores dev->desc pointer that is a reference to the original properties data. Since dev->desc is referred later, it may result in use-after-free, in the worst case, leading to a kernel Oops as reported. This patch addresses the problem by allocating and copying the properties at first, then get the desc from the copied properties. Reported-and-tested-by: Stefan Seyfried BugLink: http://bugzilla.opensuse.org/show_bug.cgi?id=1181104 Cc: Signed-off-by: Takashi Iwai Reviewed-by: Robert Foss --- drivers/media/usb/dvb-usb/dvb-usb-init.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c index 5befec87f26a..07ff9b4d2f34 100644 --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c @@ -255,27 +255,30 @@ int dvb_usb_device_init(struct usb_interface *intf, if (du != NULL) *du = NULL; - if ((desc = dvb_usb_find_device(udev, props, &cold)) == NULL) { + d = kzalloc(sizeof(struct dvb_usb_device), GFP_KERNEL); + if (!d) { + err("no memory for 'struct dvb_usb_device'"); + return -ENOMEM; + } + + memcpy(&d->props, props, sizeof(struct dvb_usb_device_properties)); + + desc = dvb_usb_find_device(udev, &d->props, &cold); + if (!desc) { deb_err("something went very wrong, device was not found in current device list - let's see what comes next.\n"); - return -ENODEV; + ret = -ENODEV; + goto error; } if (cold) { info("found a '%s' in cold state, will try to load a firmware", desc->name); ret = dvb_usb_download_firmware(udev, props); if (!props->no_reconnect || ret != 0) - return ret; + goto error; } info("found a '%s' in warm state.", desc->name); - d = kzalloc(sizeof(struct dvb_usb_device), GFP_KERNEL); - if (d == NULL) { - err("no memory for 'struct dvb_usb_device'"); - return -ENOMEM; - } - d->udev = udev; - memcpy(&d->props, props, sizeof(struct dvb_usb_device_properties)); d->desc = desc; d->owner = owner;