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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0E77C433FE for ; Mon, 27 Sep 2021 17:08:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C7B3761288 for ; Mon, 27 Sep 2021 17:08:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235852AbhI0RKQ (ORCPT ); Mon, 27 Sep 2021 13:10:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:44560 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236003AbhI0RIj (ORCPT ); Mon, 27 Sep 2021 13:08:39 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id DEE16611BD; Mon, 27 Sep 2021 17:06:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632762409; bh=x1leJY5xScm0Opflo4ns4nENcVYCHkfoZDdfvIr6wIM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QtMP8exZXznXHWetORfL5bR5e2uPO5uacXjEE326jKqvzNOx9KkXLbweEmlb8m7kc Gb51vL25kFubuOEWCDpeOgcQynzgsaA2a9D9Ui0cwgsG1XmZBOGHJ37U/NhQKymwnS 3uvlwA2jToElE25LpiZVEAqh3S13kPu+ypRAhdZE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jaejoong Kim , Oliver Neukum , Johan Hovold Subject: [PATCH 5.10 012/103] USB: cdc-acm: fix minor-number release Date: Mon, 27 Sep 2021 19:01:44 +0200 Message-Id: <20210927170226.136156232@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210927170225.702078779@linuxfoundation.org> References: <20210927170225.702078779@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johan Hovold commit 91fac0741d4817945c6ee0a17591421e7f5ecb86 upstream. If the driver runs out of minor numbers it would release minor 0 and allow another device to claim the minor while still in use. Fortunately, registering the tty class device of the second device would fail (with a stack dump) due to the sysfs name collision so no memory is leaked. Fixes: cae2bc768d17 ("usb: cdc-acm: Decrement tty port's refcount if probe() fail") Cc: stable@vger.kernel.org # 4.19 Cc: Jaejoong Kim Acked-by: Oliver Neukum Signed-off-by: Johan Hovold Link: https://lore.kernel.org/r/20210907082318.7757-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.c | 7 +++++-- drivers/usb/class/cdc-acm.h | 2 ++ 2 files changed, 7 insertions(+), 2 deletions(-) --- a/drivers/usb/class/cdc-acm.c +++ b/drivers/usb/class/cdc-acm.c @@ -726,7 +726,8 @@ static void acm_port_destruct(struct tty { struct acm *acm = container_of(port, struct acm, port); - acm_release_minor(acm); + if (acm->minor != ACM_MINOR_INVALID) + acm_release_minor(acm); usb_put_intf(acm->control); kfree(acm->country_codes); kfree(acm); @@ -1343,8 +1344,10 @@ made_compressed_probe: usb_get_intf(acm->control); /* undone in destruct() */ minor = acm_alloc_minor(acm); - if (minor < 0) + if (minor < 0) { + acm->minor = ACM_MINOR_INVALID; goto alloc_fail1; + } acm->minor = minor; acm->dev = usb_dev; --- a/drivers/usb/class/cdc-acm.h +++ b/drivers/usb/class/cdc-acm.h @@ -22,6 +22,8 @@ #define ACM_TTY_MAJOR 166 #define ACM_TTY_MINORS 256 +#define ACM_MINOR_INVALID ACM_TTY_MINORS + /* * Requests. */