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 C617AC10F14 for ; Thu, 3 Oct 2019 15:56:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8CBE321A4C for ; Thu, 3 Oct 2019 15:56:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570118198; bh=GlG6YVR+WVVS/QczyKCvj70xObEFrfnsuA3DId/ZobM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=zyqW07CZwp8k/ogT+wP4mmrW6yC3M/zsl4fdfDE3Fx1YUHGJzK2xnCn+Zk9Zg7M+s T0OfQS86DGK+K9TqKjKfsA7tQT5KubmInu+3fb9xx3DjdqDyOI6tdLVTvhUwP53+ra xQKZ6MJN27eU0s0q5YSvW9/czu4CVeVxJLG3/vzQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730699AbfJCP4i (ORCPT ); Thu, 3 Oct 2019 11:56:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:38342 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730606AbfJCP4a (ORCPT ); Thu, 3 Oct 2019 11:56:30 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 3519D21848; Thu, 3 Oct 2019 15:56:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570118188; bh=GlG6YVR+WVVS/QczyKCvj70xObEFrfnsuA3DId/ZobM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gf/U7xccfSyzg31sY44jczP2TbzlkOh4IOv5JRMV4zrIV1mANhWMSpCQvGptj08kh E4m9ywI5VLkt7FR4gLqeBw3nhjS75g9a+Y2ht+pGaiT8qSmAABFCvXmdsClORL355s Kh5tGMQPlUtkP2CEAlHrbdhFjXAbg8QqVPkrr9cc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+ce366e2b8296e25d84f5@syzkaller.appspotmail.com, =?UTF-8?q?Bj=C3=B8rn=20Mork?= , Jakub Kicinski Subject: [PATCH 4.4 21/99] cdc_ncm: fix divide-by-zero caused by invalid wMaxPacketSize Date: Thu, 3 Oct 2019 17:52:44 +0200 Message-Id: <20191003154304.368107309@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191003154252.297991283@linuxfoundation.org> References: <20191003154252.297991283@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Bjørn Mork [ Upstream commit 3fe4b3351301660653a2bc73f2226da0ebd2b95e ] Endpoints with zero wMaxPacketSize are not usable for transferring data. Ignore such endpoints when looking for valid in, out and status pipes, to make the driver more robust against invalid and meaningless descriptors. The wMaxPacketSize of the out pipe is used as divisor. So this change fixes a divide-by-zero bug. Reported-by: syzbot+ce366e2b8296e25d84f5@syzkaller.appspotmail.com Signed-off-by: Bjørn Mork Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/cdc_ncm.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -636,8 +636,12 @@ cdc_ncm_find_endpoints(struct usbnet *de u8 ep; for (ep = 0; ep < intf->cur_altsetting->desc.bNumEndpoints; ep++) { - e = intf->cur_altsetting->endpoint + ep; + + /* ignore endpoints which cannot transfer data */ + if (!usb_endpoint_maxp(&e->desc)) + continue; + switch (e->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) { case USB_ENDPOINT_XFER_INT: if (usb_endpoint_dir_in(&e->desc)) {