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 A576AC433FE for ; Wed, 19 Oct 2022 13:21:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231872AbiJSNVM (ORCPT ); Wed, 19 Oct 2022 09:21:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231607AbiJSNUn (ORCPT ); Wed, 19 Oct 2022 09:20:43 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE60DFC1D0; Wed, 19 Oct 2022 06:06:11 -0700 (PDT) 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 4AAF5B8246D; Wed, 19 Oct 2022 09:02:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A73FDC433D6; Wed, 19 Oct 2022 09:02:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666170175; bh=0yp0MeoCQn55dZ0Ly+Cfe8r8xQVfv9yqt30m368kJ1M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TgB+xAWdEjxjpbt4FFdSu7fwAD//sYyPQy40yATI72Q9z7kL+CfaZxLnYcKTiSaff pPvQI8B2wTDcUz56uN1yIcbbNorm/0M49lqFjoGeO91dA1ZjTc0GaJ9ouLdD1h4Jtl KKuTzAs0OucmyS4IxNmTylz2NoAozoRgAiS4vB9I= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Albert Briscoe , Sasha Levin Subject: [PATCH 6.0 554/862] usb: gadget: function: fix dangling pnp_string in f_printer.c Date: Wed, 19 Oct 2022 10:30:41 +0200 Message-Id: <20221019083314.455865060@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221019083249.951566199@linuxfoundation.org> References: <20221019083249.951566199@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Albert Briscoe [ Upstream commit 24b7ba2f88e04800b54d462f376512e8c41b8a3c ] When opts->pnp_string is changed with configfs, new memory is allocated for the string. It does not, however, update dev->pnp_string, even though the memory is freed. When rquesting the string, the host then gets old or corrupted data rather than the new string. The ieee 1284 id string should be allowed to change while the device is connected. The bug was introduced in commit fdc01cc286be ("usb: gadget: printer: Remove pnp_string static buffer"), which changed opts->pnp_string from a char[] to a char*. This patch changes dev->pnp_string from a char* to a char** pointing to opts->pnp_string. Fixes: fdc01cc286be ("usb: gadget: printer: Remove pnp_string static buffer") Signed-off-by: Albert Briscoe Link: https://lore.kernel.org/r/20220911223753.20417-1-albertsbriscoe@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/f_printer.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c index abec5c58f525..a881c69b1f2b 100644 --- a/drivers/usb/gadget/function/f_printer.c +++ b/drivers/usb/gadget/function/f_printer.c @@ -89,7 +89,7 @@ struct printer_dev { u8 printer_cdev_open; wait_queue_head_t wait; unsigned q_len; - char *pnp_string; /* We don't own memory! */ + char **pnp_string; /* We don't own memory! */ struct usb_function function; }; @@ -1000,16 +1000,16 @@ static int printer_func_setup(struct usb_function *f, if ((wIndex>>8) != dev->interface) break; - if (!dev->pnp_string) { + if (!*dev->pnp_string) { value = 0; break; } - value = strlen(dev->pnp_string); + value = strlen(*dev->pnp_string); buf[0] = (value >> 8) & 0xFF; buf[1] = value & 0xFF; - memcpy(buf + 2, dev->pnp_string, value); + memcpy(buf + 2, *dev->pnp_string, value); DBG(dev, "1284 PNP String: %x %s\n", value, - dev->pnp_string); + *dev->pnp_string); break; case GET_PORT_STATUS: /* Get Port Status */ @@ -1475,7 +1475,7 @@ static struct usb_function *gprinter_alloc(struct usb_function_instance *fi) kref_init(&dev->kref); ++opts->refcnt; dev->minor = opts->minor; - dev->pnp_string = opts->pnp_string; + dev->pnp_string = &opts->pnp_string; dev->q_len = opts->q_len; mutex_unlock(&opts->lock); -- 2.35.1