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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84D51C433EF for ; Fri, 3 Dec 2021 10:54:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1380130AbhLCK5l (ORCPT ); Fri, 3 Dec 2021 05:57:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237048AbhLCK5l (ORCPT ); Fri, 3 Dec 2021 05:57:41 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D98FC06173E; Fri, 3 Dec 2021 02:54:17 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D0154B82673; Fri, 3 Dec 2021 10:54:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 803FFC53FC7; Fri, 3 Dec 2021 10:54:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1638528854; bh=2mYA88Tt1gC+TWZBEbzJlGAv7cZjcjuIuSOE7ZeDp7s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bREVVl7XYvdn+RgqY5hnwPUhWJfM/LBbKelBd4DafLH8DUh55CEhmMb5YF0TxFbaL AzsSnzdc9pAG84n+gxfVHYuyxGnsOmwRGerrIwWy3gZghVMsVj5sUbY0QTY43RCEBg Xf+wcIfR1ryPXxDbI84uxUKpdLDQjfh3YNg3wtn/rETyOIXxtnKaEKyhxUKdtSJc0e QvE/Zjd7wgGSVSWRqE1PApz5xsZy+M6d91fzBzaDR+hMRWjWd+AwJFnJ9hUuvH7uOv UIC60p6QCAP++NBkKh7vzLnmJB3mVkv+urlq/GTx5Dq02gR06gjaaXxqnYih8wwAyx YehVu5e7fwdOw== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1mt6CS-0002Cw-TI; Fri, 03 Dec 2021 11:53:56 +0100 Date: Fri, 3 Dec 2021 11:53:56 +0100 From: Johan Hovold To: Zhou Qingyang Cc: kjlu@umn.edu, Felipe Balbi , Greg Kroah-Hartman , Nadezda Lutovinova , Yu Xu , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] usb: gadget: mv_u3d: Fix a NULL pointer dereference in mv_u3d_req_to_trb() Message-ID: References: <20211130172919.207823-1-zhou1615@umn.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211130172919.207823-1-zhou1615@umn.edu> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 01, 2021 at 01:29:17AM +0800, Zhou Qingyang wrote: > In mv_u3d_req_to_trb(), mv_u3d_build_trb_one() is assigned to trb and > there is a dereference of it in mv_u3d_req_to_trb(), which could lead > to a NULL pointer dereference on failure of mv_u3d_build_trb_one(). > > Fix this bug by adding a check of trb. > > This bug was found by a static analyzer. The analysis employs > differential checking to identify inconsistent security operations > (e.g., checks or kfrees) between two code paths and confirms that the > inconsistent operations are not recovered in the current function or > the callers, so they constitute bugs. > > Note that, as a bug found by static analysis, it can be a false > positive or hard to trigger. Multiple researchers have cross-reviewed > the bug. > > Builds with CONFIG_USB_MV_U3D=m show no new warnings, > and our static analyzer no longer warns about this code. > > Fixes: 3d4eb9dfa3e8 ("usb: gadget: mv: Add USB 3.0 device driver for Marvell PXA2128 chip.") > Signed-off-by: Zhou Qingyang > --- > drivers/usb/gadget/udc/mv_u3d_core.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/usb/gadget/udc/mv_u3d_core.c b/drivers/usb/gadget/udc/mv_u3d_core.c > index a1057ddfbda3..e90ef4046a9d 100644 > --- a/drivers/usb/gadget/udc/mv_u3d_core.c > +++ b/drivers/usb/gadget/udc/mv_u3d_core.c > @@ -417,6 +417,12 @@ static int mv_u3d_req_to_trb(struct mv_u3d_req *req) > */ > if (length <= (unsigned)MV_U3D_EP_MAX_LENGTH_TRANSFER) { > trb = mv_u3d_build_trb_one(req, &count, &dma); > + if (!trb) { > + dev_err(u3d->dev, "%s, mv_u3d_build_trb_one fail\n", > + __func__); This looks correct, but the error message isn't needed as failures would already have been logged by the helper (allocator). > + return -ENOMEM; > + } > + > list_add_tail(&trb->trb_list, &req->trb_list); > req->trb_head = trb; > req->trb_count = 1; Johan