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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 117C8C352A3 for ; Mon, 10 Feb 2020 13:36:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DCE5F2070A for ; Mon, 10 Feb 2020 13:36:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581341783; bh=rv+mI0w3hDpCkcgcs2ovUWMg5x7dJNDtrZDs+5eGnoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=AYiMgFyVGFsi1T5PZcXUAVsL37Gvj47fur65xVFS4yFREcvgq6MKoMYJg7oMGPXBo /0g8gZw1wufyRuN8zvDSnoAEC9DPuDqp63ao1pE1vMhv8/qfazASibz6Txq2GxAwK1 L07evq08uvjN7wH+shkhXc8HRx0hg1vUBWRYlIPY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728190AbgBJNgX (ORCPT ); Mon, 10 Feb 2020 08:36:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:51458 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727691AbgBJMfM (ORCPT ); Mon, 10 Feb 2020 07:35:12 -0500 Received: from localhost (unknown [209.37.97.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B6C5D215A4; Mon, 10 Feb 2020 12:35:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338110; bh=rv+mI0w3hDpCkcgcs2ovUWMg5x7dJNDtrZDs+5eGnoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GUC4+wSaTjDtHKOYXrKrglRmQqUoFcpN2edjquC40cghx56TqC0QM9eHtEpX8M6Vq NxrgW5GMbfRM40X+ljwB9g6tK+lld4TGUfaX7FVAzQb3aTykfree3Wo8h1QlkM4xg3 GEKU2IQ8vFZmvpklsHEWg7ok22EB40hu5zc6DLY8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Bryan ODonoghue , Felipe Balbi Subject: [PATCH 4.19 035/195] usb: gadget: f_ecm: Use atomic_t to track in-flight request Date: Mon, 10 Feb 2020 04:31:33 -0800 Message-Id: <20200210122309.994950758@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200210122305.731206734@linuxfoundation.org> References: <20200210122305.731206734@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Bryan O'Donoghue commit d710562e01c48d59be3f60d58b7a85958b39aeda upstream. Currently ecm->notify_req is used to flag when a request is in-flight. ecm->notify_req is set to NULL and when a request completes it is subsequently reset. This is fundamentally buggy in that the unbind logic of the ECM driver will unconditionally free ecm->notify_req leading to a NULL pointer dereference. Fixes: da741b8c56d6 ("usb ethernet gadget: split CDC Ethernet function") Cc: stable Signed-off-by: Bryan O'Donoghue Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_ecm.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) --- a/drivers/usb/gadget/function/f_ecm.c +++ b/drivers/usb/gadget/function/f_ecm.c @@ -52,6 +52,7 @@ struct f_ecm { struct usb_ep *notify; struct usb_request *notify_req; u8 notify_state; + atomic_t notify_count; bool is_open; /* FIXME is_open needs some irq-ish locking @@ -380,7 +381,7 @@ static void ecm_do_notify(struct f_ecm * int status; /* notification already in flight? */ - if (!req) + if (atomic_read(&ecm->notify_count)) return; event = req->buf; @@ -420,10 +421,10 @@ static void ecm_do_notify(struct f_ecm * event->bmRequestType = 0xA1; event->wIndex = cpu_to_le16(ecm->ctrl_id); - ecm->notify_req = NULL; + atomic_inc(&ecm->notify_count); status = usb_ep_queue(ecm->notify, req, GFP_ATOMIC); if (status < 0) { - ecm->notify_req = req; + atomic_dec(&ecm->notify_count); DBG(cdev, "notify --> %d\n", status); } } @@ -448,17 +449,19 @@ static void ecm_notify_complete(struct u switch (req->status) { case 0: /* no fault */ + atomic_dec(&ecm->notify_count); break; case -ECONNRESET: case -ESHUTDOWN: + atomic_set(&ecm->notify_count, 0); ecm->notify_state = ECM_NOTIFY_NONE; break; default: DBG(cdev, "event %02x --> %d\n", event->bNotificationType, req->status); + atomic_dec(&ecm->notify_count); break; } - ecm->notify_req = req; ecm_do_notify(ecm); } @@ -907,6 +910,11 @@ static void ecm_unbind(struct usb_config usb_free_all_descriptors(f); + if (atomic_read(&ecm->notify_count)) { + usb_ep_dequeue(ecm->notify, ecm->notify_req); + atomic_set(&ecm->notify_count, 0); + } + kfree(ecm->notify_req->buf); usb_ep_free_request(ecm->notify, ecm->notify_req); }