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 5B1B0C10F14 for ; Thu, 3 Oct 2019 16:15:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 259C3215EA for ; Thu, 3 Oct 2019 16:15:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570119321; bh=2NQHd2QxdKNhEULOQ3m6pk/Bq8wN86OiE8oTa6a2Tsg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VXOPtI+RqbI1tF9rPGS+R4FWZUpxbCAxI9DvpPY9weAO547ZA/oPZsHxDW67fcIIF Df6BzVrmPAwD5dx1decGY6MivDU/vo2Wz4mDRyxuDCvlmaFIbWIOAU6azhw1AnPBcM fRwrQFEmw4rlPkVp1+H7fwtIcWwMez3eWWQyByZw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388232AbfJCQPT (ORCPT ); Thu, 3 Oct 2019 12:15:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:39238 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388848AbfJCQPP (ORCPT ); Thu, 3 Oct 2019 12:15:15 -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 E3D8C20865; Thu, 3 Oct 2019 16:15:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570119314; bh=2NQHd2QxdKNhEULOQ3m6pk/Bq8wN86OiE8oTa6a2Tsg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=h1p+bt3tPe71/F3cyZHi+sNNRJIBrJJ1zt+TByJTYPNHENm5o2N9Qy9VfDkC/Ory9 jZamKRJJstF1hY0t3124GmdcgpyONiBCUkdk45scNwREwoknql/u7dLWpTLCEhSWKK lq03jLYSO/fu3Tb5AAYg4NAf7EewGcFidCmJdHfI= 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 4.19 002/211] cdc_ncm: fix divide-by-zero caused by invalid wMaxPacketSize Date: Thu, 3 Oct 2019 17:51:08 +0200 Message-Id: <20191003154447.588223033@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20191003154447.010950442@linuxfoundation.org> References: <20191003154447.010950442@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 @@ -681,8 +681,12 @@ 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)) {