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 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 89EDFC48BC2 for ; Mon, 21 Jun 2021 14:12:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 728D26124B for ; Mon, 21 Jun 2021 14:12:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229789AbhFUOOw (ORCPT ); Mon, 21 Jun 2021 10:14:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230021AbhFUOOb (ORCPT ); Mon, 21 Jun 2021 10:14:31 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B195C061756; Mon, 21 Jun 2021 07:12:14 -0700 (PDT) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 02DAC5C75; Mon, 21 Jun 2021 16:12:12 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1624284733; bh=aRDvLGDHkllkAXYqx0yCOiC9NL5De0JywflMx1qqRCA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ai5eTMDukpcInGM+jSkdvRqZVlC9MmtY+ZldIvkPk4B1/Nlm7GKDLnzQc4jCQ40oV O1DsiQ8FT8UNHKsHp2GT4KBLo2itsU2s20bmSM9LuEhIrzkELB7l8roILCWfd8CkNh a1ntv6PxYGesokKvaMEHXDDWNjRekkFXv8z7dqS8= Date: Mon, 21 Jun 2021 17:11:46 +0300 From: Laurent Pinchart To: Mauro Carvalho Chehab Cc: linuxarm@huawei.com, mauro.chehab@huawei.com, Mauro Carvalho Chehab , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH v3] media: uvc: don't do DMA on stack Message-ID: References: <6832dffafd54a6a95b287c4a1ef30250d6b9237a.1624282817.git.mchehab+huawei@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <6832dffafd54a6a95b287c4a1ef30250d6b9237a.1624282817.git.mchehab+huawei@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mauro, Thank you for the patch. On Mon, Jun 21, 2021 at 03:40:19PM +0200, Mauro Carvalho Chehab wrote: > As warned by smatch: > drivers/media/usb/uvc/uvc_v4l2.c:911 uvc_ioctl_g_input() error: doing dma on the stack (&i) > drivers/media/usb/uvc/uvc_v4l2.c:943 uvc_ioctl_s_input() error: doing dma on the stack (&i) > > those two functions call uvc_query_ctrl passing a pointer to > a data at the DMA stack. those are used to send URBs via > usb_control_msg(). Using DMA stack is not supported and should > not work anymore on modern Linux versions. > > So, use a kmalloc'ed buffer. > > Cc: stable@vger.kernel.org # Kernel 4.9 and upper > Signed-off-by: Mauro Carvalho Chehab > --- > drivers/media/usb/uvc/uvc_v4l2.c | 30 ++++++++++++++++++++++-------- > 1 file changed, 22 insertions(+), 8 deletions(-) > > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c > index 252136cc885c..a95bf7318848 100644 > --- a/drivers/media/usb/uvc/uvc_v4l2.c > +++ b/drivers/media/usb/uvc/uvc_v4l2.c > @@ -899,8 +899,8 @@ static int uvc_ioctl_g_input(struct file *file, void *fh, unsigned int *input) > { > struct uvc_fh *handle = fh; > struct uvc_video_chain *chain = handle->chain; > + u8 *buf; > int ret; > - u8 i; > > if (chain->selector == NULL || > (chain->dev->quirks & UVC_QUIRK_IGNORE_SELECTOR_UNIT)) { > @@ -908,13 +908,20 @@ static int uvc_ioctl_g_input(struct file *file, void *fh, unsigned int *input) > return 0; > } > > + buf = kmalloc(1, GFP_KERNEL); > + if (!buf) > + return -ENOMEM; > + > ret = uvc_query_ctrl(chain->dev, UVC_GET_CUR, chain->selector->id, > chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, > - &i, 1); > + buf, 1); > if (ret < 0) > return ret; Memory leak :-) if (!ret) *input = *buf - 1; kfree(buf); return ret; > > - *input = i - 1; > + *input = *buf - 1; > + > + kfree(buf); > + > return 0; > } > > @@ -922,8 +929,8 @@ static int uvc_ioctl_s_input(struct file *file, void *fh, unsigned int input) > { > struct uvc_fh *handle = fh; > struct uvc_video_chain *chain = handle->chain; > + char *buf; u8 *buf; With these two changes, Reviewed-by: Laurent Pinchart Do I need to take the patch in my tree ? > int ret; > - u32 i; > > ret = uvc_acquire_privileges(handle); > if (ret < 0) > @@ -939,10 +946,17 @@ static int uvc_ioctl_s_input(struct file *file, void *fh, unsigned int input) > if (input >= chain->selector->bNrInPins) > return -EINVAL; > > - i = input + 1; > - return uvc_query_ctrl(chain->dev, UVC_SET_CUR, chain->selector->id, > - chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, > - &i, 1); > + buf = kmalloc(1, GFP_KERNEL); > + if (!buf) > + return -ENOMEM; > + > + *buf = input + 1; > + ret = uvc_query_ctrl(chain->dev, UVC_SET_CUR, chain->selector->id, > + chain->dev->intfnum, UVC_SU_INPUT_SELECT_CONTROL, > + buf, 1); > + kfree(buf); > + > + return ret; > } > > static int uvc_ioctl_queryctrl(struct file *file, void *fh, -- Regards, Laurent Pinchart