From nobody Fri Dec 19 19:14:28 2025 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 7D95AC38A2D for ; Mon, 24 Oct 2022 14:08:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229967AbiJXOH5 (ORCPT ); Mon, 24 Oct 2022 10:07:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236957AbiJXOEM (ORCPT ); Mon, 24 Oct 2022 10:04:12 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F20FE90811; Mon, 24 Oct 2022 05:49:07 -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 dfw.source.kernel.org (Postfix) with ESMTPS id B1CB06134C; Mon, 24 Oct 2022 12:47:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C0459C433D6; Mon, 24 Oct 2022 12:47:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666615631; bh=0yp0MeoCQn55dZ0Ly+Cfe8r8xQVfv9yqt30m368kJ1M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bdr/nQp8157SAdL6QS1S4VICElTgzPOm6zNAo7hHdIIS/cglF2xmeQxeppug63MHR Hc3q5BO0nacCfwTEzDOKY6mOt+RhKC+nRLyB08TCtZWdELq2tb33HulneIv5IL5cyr g9JrN5vxaiO9S1ctIjLf5hmIRernKMBRTzbmgQNE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Albert Briscoe , Sasha Levin Subject: [PATCH 5.15 323/530] usb: gadget: function: fix dangling pnp_string in f_printer.c Date: Mon, 24 Oct 2022 13:31:07 +0200 Message-Id: <20221024113059.654682359@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024113044.976326639@linuxfoundation.org> References: <20221024113044.976326639@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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/f= unction/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; }; =20 @@ -1000,16 +1000,16 @@ static int printer_func_setup(struct usb_function *= f, if ((wIndex>>8) !=3D dev->interface) break; =20 - if (!dev->pnp_string) { + if (!*dev->pnp_string) { value =3D 0; break; } - value =3D strlen(dev->pnp_string); + value =3D strlen(*dev->pnp_string); buf[0] =3D (value >> 8) & 0xFF; buf[1] =3D 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; =20 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 =3D opts->minor; - dev->pnp_string =3D opts->pnp_string; + dev->pnp_string =3D &opts->pnp_string; dev->q_len =3D opts->q_len; mutex_unlock(&opts->lock); =20 --=20 2.35.1