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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 07D48ECE58A for ; Tue, 1 Oct 2019 16:46:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C49582168B for ; Tue, 1 Oct 2019 16:46:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569948380; bh=1ee7sxbn4JjLSbLQY0Vh4Xq0lJhiXg73E44qe5nVG98=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=xfo1PuIc3oPjrlgNRGq7NZRLu07GWS4tcvyf5dVeIIK4+fX+CVWhQlUqUKAP+EkaI lYhvwwA8a920vlUZa8wIOhpozS92znObIwrHy3/tmalfZGaRiG2M2FRydOjhLidHe2 JYHKVoEjgiD4m04H35+A9EaW3l8Mhhn9U8ofjpvU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390405AbfJAQpq (ORCPT ); Tue, 1 Oct 2019 12:45:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:58296 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390375AbfJAQpn (ORCPT ); Tue, 1 Oct 2019 12:45:43 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3889A21A4A; Tue, 1 Oct 2019 16:45:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569948343; bh=1ee7sxbn4JjLSbLQY0Vh4Xq0lJhiXg73E44qe5nVG98=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ADAkyvYmqWbnJ0Fjcg/Ltam8m6OsMXIYaCXO/QcsnPL+BB4bkEbPEvZ/6rwZd/jOj KgpZ6shaGlG+1IjRVdmgweoIV1SRAF9/9I8vDfk8y8qYpIkuCyVPe4AFNmjW/iWtV7 Iq3UcQjugGxERtOjIBkyy41Ch5l2vQxoJ1Xcr6/I= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?UTF-8?q?Bj=C3=B8rn=20Mork?= , syzbot+ce366e2b8296e25d84f5@syzkaller.appspotmail.com, Jakub Kicinski , Sasha Levin , linux-usb@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.4 07/15] cdc_ncm: fix divide-by-zero caused by invalid wMaxPacketSize Date: Tue, 1 Oct 2019 12:45:25 -0400 Message-Id: <20191001164533.16915-7-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191001164533.16915-1-sashal@kernel.org> References: <20191001164533.16915-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore 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: Sasha Levin --- drivers/net/usb/cdc_ncm.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index 1e921e5eddc7f..442efbccd0051 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -636,8 +636,12 @@ cdc_ncm_find_endpoints(struct usbnet *dev, struct usb_interface *intf) 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)) { -- 2.20.1