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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 3B655C4361A for ; Fri, 22 Jan 2021 17:31:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E834239D4 for ; Fri, 22 Jan 2021 17:31:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730076AbhAVRbC (ORCPT ); Fri, 22 Jan 2021 12:31:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40820 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729054AbhAVPtD (ORCPT ); Fri, 22 Jan 2021 10:49:03 -0500 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9DEBC06121F for ; Fri, 22 Jan 2021 07:47:56 -0800 (PST) Received: by mail-pj1-x1036.google.com with SMTP id a20so964182pjs.1 for ; Fri, 22 Jan 2021 07:47:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=PdDUQpTTa/vebneMqETLs1lh6NBTqik+/UKGsjcfFuA=; b=G2h3gZ1xMzLQcLHaMMKuEtrk5L0QFUsRVk6hsENZlqp97AS6CpCWM0Y5q2S675Mdeb +jt/VBO+dPr1gkg5n7Qw64zZm+VmHJO31JetwJAti5wt6edbArj6PXxsjBEvk4xsHEjK Rl4gwlFI/R7FOH1BptElZxodhJrWGklgTs8XwJcEFZ7eYS5ONzaNZGvIrrPHWnAdO47z kK9wy86MQb0zUOV/wpw7VeeQIgmnBpRSUPHKQCnfzerbYbvWZ8MlKY+aGGqBYKKw0XUq eV0/P4/x3Sh0sDaMCk3xdhRBDad9NoHBoZzoKMe9Ff6Bn93KHAnt0gC50TriOZjo+RLN AdbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=PdDUQpTTa/vebneMqETLs1lh6NBTqik+/UKGsjcfFuA=; b=GERA8In307/8wgrz1HnoxsooU/Hd5eFxNc+Z1XXmikyjp1h4DsV+Qt0k2yjgmoZi3g ED9fkm33gEhhmzrNePNBqmWFZBySXAifs+sKp8zsKwxkhABQ7Cg/N7v10g/j6suVbxZc eheAGsayZF/zsp9z7WThL895SkTga4NfpawGkm7vl7RSHgpaHxJzmRo9vUhDokgkkViq w6w1rzTZNVtGh54a919dEdPMMiUfhs/IgdyPJUJKQL6ZPlpitylejWAZTtP1m6SQ4nip iCf1r6+Ch+wsfAdzptVuDlsMUhudpeVVcapyxw4VHhLIlHi/5IkGfYvothn9qJOMfzoV b/ZQ== X-Gm-Message-State: AOAM5335IaRty94ETcoYXFYIkeOq3n3Gmn6qjt9WVRh0qkuNYq6sESBX 9j7EZ8yMWC0f6RTDOPIr9dJPxR5C/VFaUHqyVXY8wz0QpN0= X-Google-Smtp-Source: ABdhPJyKaM6heiVs45DHGJ5aMpMXwPplfaambFQiceQ90sJC2VZv0DYdU3XWcYdf5upOXpJA9LsjJJudVgruxTUwmRw= X-Received: by 2002:a17:90a:d913:: with SMTP id c19mr6215690pjv.19.1611330476335; Fri, 22 Jan 2021 07:47:56 -0800 (PST) MIME-Version: 1.0 References: <20210120102057.21143-1-tiwai@suse.de> <20210120102057.21143-3-tiwai@suse.de> In-Reply-To: <20210120102057.21143-3-tiwai@suse.de> From: Robert Foss Date: Fri, 22 Jan 2021 16:47:44 +0100 Message-ID: Subject: Re: [PATCH 2/2] media: dvb-usb: Fix use-after-free access To: Takashi Iwai Cc: Mauro Carvalho Chehab , linux-media , linux-kernel , Stefan Seyfried Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hey Takashi, This patch is generating a checkpatch warning, but I think it is spurious and can be ignored. Other than that, this looks good to me. Reviewed-by: Robert Foss On Wed, 20 Jan 2021 at 12:51, Takashi Iwai wrote: > > 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 > --- > 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; > > -- > 2.26.2 >