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 4A0FAC433EF for ; Thu, 6 Jan 2022 14:35:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240193AbiAFOfc (ORCPT ); Thu, 6 Jan 2022 09:35:32 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:49526 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240103AbiAFOfb (ORCPT ); Thu, 6 Jan 2022 09:35:31 -0500 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 dfw.source.kernel.org (Postfix) with ESMTPS id 1633761CB5; Thu, 6 Jan 2022 14:35:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE3BFC36AE3; Thu, 6 Jan 2022 14:35:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1641479730; bh=ulwEaw59sG7ePO1RDYpCAz04ZJ1s19bdU4we6iDT9WE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mJnOjpkv15USUzRGO+GZ/rjroa/evK3aJ7WheN5Z/SGCTVWnF6MCnaO5W8tROCKPP +pbu7KUhF8BRtYVCOCnA2tBUyJ+OecFRxnptmmw7ANugrOBJ7eA7YZAEbffUT/d/CR ubLlH2vlCGl2F1syaLNLFDbZDoZc2dmXnfGMbcnA= Date: Thu, 6 Jan 2022 15:35:27 +0100 From: Greg KH To: Wei Ming Chen Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, balbi@kernel.org, maze@google.com Subject: Re: [PATCH] usb: gadget: function: Fix returning incorrect PNP string Message-ID: References: <20220105040439.3182-1-jj251510319013@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220105040439.3182-1-jj251510319013@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 05, 2022 at 12:04:39PM +0800, Wei Ming Chen wrote: > There will be 2 leading bytes indicating the total length of > the PNP string, so I think we should add value by 2, otherwise > the PNP string copied to user will not contain the last 2 bytes > > Signed-off-by: Wei Ming Chen > --- > drivers/usb/gadget/function/f_printer.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c > index abec5c58f525..3fb00fd0b5ee 100644 > --- a/drivers/usb/gadget/function/f_printer.c > +++ b/drivers/usb/gadget/function/f_printer.c > @@ -1005,9 +1005,11 @@ static int printer_func_setup(struct usb_function *f, > break; > } > value = strlen(dev->pnp_string); > + memcpy(buf + 2, dev->pnp_string, value); > + > + value += 2; > buf[0] = (value >> 8) & 0xFF; > buf[1] = value & 0xFF; > - memcpy(buf + 2, dev->pnp_string, value); > DBG(dev, "1284 PNP String: %x %s\n", value, > dev->pnp_string); > break; > -- > 2.25.1 > Are you sure this is correct? How is this related to this recent thread: https://lore.kernel.org/all/CAKjGFBUdjXcZoVV4jdrgTz4rKThTfZAK4CqreKmBZ4KHE+K1GA@mail.gmail.com/#t your change is different from what is proposed there, why? thanks, greg k-h