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 04E02ECE587 for ; Tue, 1 Oct 2019 16:48:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C6A4920659 for ; Tue, 1 Oct 2019 16:48:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569948518; bh=9mMIkBZPeq4VbAZVxocW/1TTx4JVNHnDdhE/8JTQTNY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=H2lC3aCDkcrsEGk409tVBa/veePmFePHp8659Nowo3ckbcdaD8YMLS0jZ9vlIczrB nvfeeJjZXzGtvY9880UbR/BqwJb0q/Z7TBVoHVGib4qEJuldtjznwum1+fs+czCdns 4R8rxOpvqVUEVx+TxHDbKI06CK9chdINsC7ibGtk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388781AbfJAQsh (ORCPT ); Tue, 1 Oct 2019 12:48:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:57696 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390219AbfJAQpR (ORCPT ); Tue, 1 Oct 2019 12:45:17 -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 945AF21920; Tue, 1 Oct 2019 16:45:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569948316; bh=9mMIkBZPeq4VbAZVxocW/1TTx4JVNHnDdhE/8JTQTNY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q94CmLpx2qwtE2yEb69MkmVFmW5wjPPSpF4v0v6YjrA+APloZWtxXmoTcPnHODchQ +uqMQnSSxisMOdZaWMYT67s0YXLcXeDD4ZlSmF49FjyoiUKACJjheg4LriBCm/oxe4 pUblBokgHJ3e64hI2TVzxDdL12SMGb6md1pH8Hrk= 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 4.9 08/19] cdc_ncm: fix divide-by-zero caused by invalid wMaxPacketSize Date: Tue, 1 Oct 2019 12:44:54 -0400 Message-Id: <20191001164505.16708-8-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191001164505.16708-1-sashal@kernel.org> References: <20191001164505.16708-1-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 7b158674ceeda..43e28d2b0de7f 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -679,8 +679,12 @@ 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