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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C385C4321E for ; Mon, 25 Oct 2021 11:46:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAF5361002 for ; Mon, 25 Oct 2021 11:46:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233256AbhJYLsr (ORCPT ); Mon, 25 Oct 2021 07:48:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:39204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233250AbhJYLsn (ORCPT ); Mon, 25 Oct 2021 07:48:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7FF2461073; Mon, 25 Oct 2021 11:46:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1635162381; bh=VpXDuc5ODD37c89+RKGeszqjBvCk2D5GP/X21UhgFC0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=phnnXdVJEPrhUoSVUAdSnVJSm+QykpAXYCVH9cjYbnX0ExfPHMb/gfJNxP9DBXDII CTUAW4lEJY32pZX6ENn3OfAFoxCmP7yHHmwOLGv+5ioF9X2NFpMLJG2n7plpNxTie8 25GSduHAEiNqcZ4UJ/aqZ1ZQzRobM04KgvIu4s1FKUj0MxtscgpTLdTP/PEND7KhRM tnqrfswOIHhQZJHLn5yxqSxyEH73pj5DU6a5nZltvWcnA+zjThDjdWm08hadWlKUSh 1CuQJQqlW9vcLaUXGfwwpdXc8H2JPvnrDg54SjxAlyjxDw7c+cCR4R/BDuJbO3b1h1 pFShIeJdcyCEg== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1meyQW-0001DI-Ac; Mon, 25 Oct 2021 13:46:04 +0200 From: Johan Hovold To: Ian Abbott , H Hartley Sweeten Cc: Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold , stable@vger.kernel.org Subject: [PATCH 3/5] comedi: vmk80xx: fix transfer-buffer overflows Date: Mon, 25 Oct 2021 13:45:30 +0200 Message-Id: <20211025114532.4599-4-johan@kernel.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20211025114532.4599-1-johan@kernel.org> References: <20211025114532.4599-1-johan@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The driver uses endpoint-sized USB transfer buffers but up until recently had no sanity checks on the sizes. Commit e1f13c879a7c ("staging: comedi: check validity of wMaxPacketSize of usb endpoints found") inadvertently fixed NULL-pointer dereferences when accessing the transfer buffers in case a malicious device has a zero wMaxPacketSize. Make sure to allocate buffers large enough to handle also the other accesses that are done without a size check (e.g. byte 18 in vmk80xx_cnt_insn_read() for the VMK8061_MODEL) to avoid writing beyond the buffers, for example, when doing descriptor fuzzing. The original driver was for a low-speed device with 8-byte buffers. Support was later added for a device that uses bulk transfers and is presumably a full-speed device with a maximum 64-byte wMaxPacketSize. Fixes: 985cafccbf9b ("Staging: Comedi: vmk80xx: Add k8061 support") Cc: stable@vger.kernel.org # 2.6.31 Signed-off-by: Johan Hovold --- drivers/comedi/drivers/vmk80xx.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/comedi/drivers/vmk80xx.c b/drivers/comedi/drivers/vmk80xx.c index 9f920819cd74..f2c1572d0cd7 100644 --- a/drivers/comedi/drivers/vmk80xx.c +++ b/drivers/comedi/drivers/vmk80xx.c @@ -90,6 +90,8 @@ enum { #define IC3_VERSION BIT(0) #define IC6_VERSION BIT(1) +#define MIN_BUF_SIZE 64 + enum vmk80xx_model { VMK8055_MODEL, VMK8061_MODEL @@ -678,12 +680,12 @@ static int vmk80xx_alloc_usb_buffers(struct comedi_device *dev) struct vmk80xx_private *devpriv = dev->private; size_t size; - size = usb_endpoint_maxp(devpriv->ep_rx); + size = max(usb_endpoint_maxp(devpriv->ep_rx), MIN_BUF_SIZE); devpriv->usb_rx_buf = kzalloc(size, GFP_KERNEL); if (!devpriv->usb_rx_buf) return -ENOMEM; - size = usb_endpoint_maxp(devpriv->ep_tx); + size = max(usb_endpoint_maxp(devpriv->ep_rx), MIN_BUF_SIZE); devpriv->usb_tx_buf = kzalloc(size, GFP_KERNEL); if (!devpriv->usb_tx_buf) return -ENOMEM; -- 2.32.0