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=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 89748ECE587 for ; Tue, 1 Oct 2019 16:44:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 563A120B7C for ; Tue, 1 Oct 2019 16:44:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569948298; bh=58+D/0Nn5aEzAP8N0Mz6aHEHd5/96U8SlzotQWH0twA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rezwPWrQimK3YK2dEkoGVPbwr/GU0BqIFCfd1BtRpYRq2B+fi9YYs0jby16Lyc1Jf zzRn94OEsEYlzMM9NYh+qE8FRgD3b4wD+kBt5cUe1zHtndwLhO98KTKx9yBffoafXS sfFRiY/VYTTuLYzRJmgea2bLLubh7mkU2p3mIPRw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726670AbfJAQo5 (ORCPT ); Tue, 1 Oct 2019 12:44:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:57002 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390036AbfJAQom (ORCPT ); Tue, 1 Oct 2019 12:44:42 -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 97BFE21906; Tue, 1 Oct 2019 16:44:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569948281; bh=58+D/0Nn5aEzAP8N0Mz6aHEHd5/96U8SlzotQWH0twA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CYHuWg5TZdZV5hZWg9KNyiaOIxx0RFyRjLBb5Ns9jT8hoL2SpjF4a8loGlyuh4GsS 6dQntCBv4Xq8MHybgr6FnC8P+YM+F+D4mFuW9zt63BvgFqtD7Q3MxnNGBXjSPuhSLf YiI2A4xurdVNDEmMP7dla80oMihAHdZhHjtvMrVI= 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 4.14 14/29] cdc_ncm: fix divide-by-zero caused by invalid wMaxPacketSize Date: Tue, 1 Oct 2019 12:44:08 -0400 Message-Id: <20191001164423.16406-14-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191001164423.16406-1-sashal@kernel.org> References: <20191001164423.16406-1-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 f5316ab68a0a8..ab28487e60484 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -681,8 +681,12 @@ 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