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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 8CD4EC3A5A1 for ; Thu, 22 Aug 2019 17:31:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5984A23400 for ; Thu, 22 Aug 2019 17:31:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566495089; bh=dj7mEkG4videPuN9hCV/MWfKJniVmyHGSAILoiUiZLg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uPbDf7/QWwLd27JnEnPKokAJh2LRIOuhPsfKom/Xdv3iMTwpCuXON+YF0hn6y54u4 Dg4RuWbyBu7w9XG6pwn5c/i9loMr50JXEU1A4+9tOOn7FpKabigh30vW52idgUgQ+M WWYxLXvogBFMxzxxN6T6Yll/DzszkUfgej8DrcjE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392240AbfHVRb1 (ORCPT ); Thu, 22 Aug 2019 13:31:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:49862 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404534AbfHVRZ4 (ORCPT ); Thu, 22 Aug 2019 13:25:56 -0400 Received: from localhost (wsip-184-188-36-2.sd.sd.cox.net [184.188.36.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A79A52342B; Thu, 22 Aug 2019 17:25:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566494755; bh=dj7mEkG4videPuN9hCV/MWfKJniVmyHGSAILoiUiZLg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ijfkt63oRWWACijW6697/D9l7LVsKcN0Ii0pOa2FdnPSdhd8cZxD1HAOJqF1LNsNQ D5Md/WIp4Q2V9vQat/EmZn7aovuXl/0T9Iqr8547kOQrHYJj8jecLp+lEahFBt+2Ho 2w85P0OVMC65osWAQ0LMQXjfTaWGohln0zYYS8hs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Binderman , Ian Abbott Subject: [PATCH 4.19 56/85] staging: comedi: dt3000: Fix signed integer overflow divider * base Date: Thu, 22 Aug 2019 10:19:29 -0700 Message-Id: <20190822171733.646826894@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190822171731.012687054@linuxfoundation.org> References: <20190822171731.012687054@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ian Abbott commit b4d98bc3fc93ec3a58459948a2c0e0c9b501cd88 upstream. In `dt3k_ns_to_timer()` the following lines near the end of the function result in a signed integer overflow: prescale = 15; base = timer_base * (1 << prescale); divider = 65535; *nanosec = divider * base; (`divider`, `base` and `prescale` are type `int`, `timer_base` and `*nanosec` are type `unsigned int`. The value of `timer_base` will be either 50 or 100.) The main reason for the overflow is that the calculation for `base` is completely wrong. It should be: base = timer_base * (prescale + 1); which matches an earlier instance of this calculation in the same function. Reported-by: David Binderman Cc: Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/20190812111517.26803-1-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/dt3000.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/staging/comedi/drivers/dt3000.c +++ b/drivers/staging/comedi/drivers/dt3000.c @@ -368,7 +368,7 @@ static int dt3k_ns_to_timer(unsigned int } prescale = 15; - base = timer_base * (1 << prescale); + base = timer_base * (prescale + 1); divider = 65535; *nanosec = divider * base; return (prescale << 16) | (divider);