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=-13.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 7524AC433E7 for ; Fri, 17 Jul 2020 14:53:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 511192070E for ; Fri, 17 Jul 2020 14:53:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mev.co.uk header.i=@mev.co.uk header.b="DFyrxdct" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727107AbgGQOx3 (ORCPT ); Fri, 17 Jul 2020 10:53:29 -0400 Received: from smtp102.iad3b.emailsrvr.com ([146.20.161.102]:44644 "EHLO smtp102.iad3b.emailsrvr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726812AbgGQOxX (ORCPT ); Fri, 17 Jul 2020 10:53:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mev.co.uk; s=20190130-41we5z8j; t=1594997602; bh=41TBdif6gLbsLqcqOknalhHkQbgUsySHykQ3g+6yXxo=; h=From:To:Subject:Date:From; b=DFyrxdctkfp0IY1vzdLKvvL9xebBaF+kEB2EX6LCvmphiEcqvD6qgjJtRQ/KvMmRp 8dsL3lBOZKpU2vSuJvmeVxrydXMSsrZ5kgVWOT4yOiRW6rfjMdELYcpmv0+NZolF0k HucS+03tMqnsPYaIW1zRKavyTsV6v+JW12Gt5rLE= X-Auth-ID: abbotti@mev.co.uk Received: by smtp5.relay.iad3b.emailsrvr.com (Authenticated sender: abbotti-AT-mev.co.uk) with ESMTPSA id 8DC724020E; Fri, 17 Jul 2020 10:53:21 -0400 (EDT) From: Ian Abbott To: devel@driverdev.osuosl.org Cc: Greg Kroah-Hartman , Ian Abbott , H Hartley Sweeten , linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 4/4] staging: comedi: addi_apci_1500: check INSN_CONFIG_DIGITAL_TRIG shift Date: Fri, 17 Jul 2020 15:52:57 +0100 Message-Id: <20200717145257.112660-5-abbotti@mev.co.uk> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200717145257.112660-1-abbotti@mev.co.uk> References: <20200717145257.112660-1-abbotti@mev.co.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Classification-ID: 3cd28aa4-5d40-4a0c-a681-8cbccbead0a1-5-1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The `INSN_CONFIG` comedi instruction with sub-instruction code `INSN_CONFIG_DIGITAL_TRIG` includes a base channel in `data[3]`. This is used as a right shift amount for other bitmask values without being checked. Shift amounts greater than or equal to 32 will result in undefined behavior. Add code to deal with this, adjusting the checks for invalid channels so that enabled channel bits that would have been lost by shifting are also checked for validity. Only channels 0 to 15 are valid. Fixes: a8c66b684efaf ("staging: comedi: addi_apci_1500: rewrite the subdevice support functions") Cc: #4.0+: ef75e14a6c93: staging: comedi: verify array index is correct before using it Cc: #4.0+ Signed-off-by: Ian Abbott --- .../staging/comedi/drivers/addi_apci_1500.c | 24 +++++++++++++++---- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/drivers/staging/comedi/drivers/addi_apci_1500.c b/drivers/staging/comedi/drivers/addi_apci_1500.c index 689acd69a1b9..816dd25b9d0e 100644 --- a/drivers/staging/comedi/drivers/addi_apci_1500.c +++ b/drivers/staging/comedi/drivers/addi_apci_1500.c @@ -452,13 +452,14 @@ static int apci1500_di_cfg_trig(struct comedi_device *dev, struct apci1500_private *devpriv = dev->private; unsigned int trig = data[1]; unsigned int shift = data[3]; - unsigned int hi_mask = data[4] << shift; - unsigned int lo_mask = data[5] << shift; - unsigned int chan_mask = hi_mask | lo_mask; - unsigned int old_mask = (1 << shift) - 1; + unsigned int hi_mask; + unsigned int lo_mask; + unsigned int chan_mask; + unsigned int old_mask; unsigned int pm; unsigned int pt; unsigned int pp; + unsigned int invalid_chan; if (trig > 1) { dev_dbg(dev->class_dev, @@ -466,7 +467,20 @@ static int apci1500_di_cfg_trig(struct comedi_device *dev, return -EINVAL; } - if (chan_mask > 0xffff) { + if (shift <= 16) { + hi_mask = data[4] << shift; + lo_mask = data[5] << shift; + old_mask = (1U << shift) - 1; + invalid_chan = (data[4] | data[5]) >> (16 - shift); + } else { + hi_mask = 0; + lo_mask = 0; + old_mask = 0xffff; + invalid_chan = data[4] | data[5]; + } + chan_mask = hi_mask | lo_mask; + + if (invalid_chan) { dev_dbg(dev->class_dev, "invalid digital trigger channel\n"); return -EINVAL; } -- 2.27.0