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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT 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 6D5E8C43387 for ; Mon, 14 Jan 2019 22:08:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 35394205F4 for ; Mon, 14 Jan 2019 22:08:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="SQU+bXrO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726933AbfANWIB (ORCPT ); Mon, 14 Jan 2019 17:08:01 -0500 Received: from mail-pl1-f195.google.com ([209.85.214.195]:39023 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726591AbfANWIA (ORCPT ); Mon, 14 Jan 2019 17:08:00 -0500 Received: by mail-pl1-f195.google.com with SMTP id 101so260658pld.6; Mon, 14 Jan 2019 14:08:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=shHou+66+RjSgcQd8m33V51MEprMke5m68diHVIUSQs=; b=SQU+bXrOHhu6I3frFOYkIAxI1I04OlkuQHps4JykshNlzR87qkKlsLZlHYbVkcBQFW 6YBCkalfT47n9xxLJ2l9qzf+6uq4XuvIzNCi6OzKgwn3dkKJ9vUdGEhVV0Lsasq0p76W R3C/ZAGVlqhdJGMKGu6kHPIQ1CB8II/oPz30Jw4ZEB3tSGmW4ps6yTGw2bCGWX5CdJZG DDwKkQxSifhAKMplWSGBdaAkHa7qe9CHA+75JeVGGI1HBEUKTJEeeH/uKPI8xmLRpbZe smRQ4zN/hOAvPoz0CRSis5dFs53IsbEvTIMOe4hrKsVEy4c7NY7hBlSCt+y0BdJ67FL8 I9eg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=shHou+66+RjSgcQd8m33V51MEprMke5m68diHVIUSQs=; b=X6Gs77k5coNAgZxgHihdc0EWf4lFtQLY5bD/R5dbPQ27doDjmlWJudJA+f9rnOjxN9 pXewYLeXGij+Co2t4w5B87A6QBbWKNEqLy7kF+419SP/UUBk9C+z4uw21s1nYSEFmwKm LMu6Ff5vNDRuOO2HwGSU6zZvo2mbFuEm5lOsDDqRflTk/8Xs2q3ZugfBjo/9Y88h8OuF Ejqh1/BsIcQKB4QNPW9AZzrrY5nT6BnodkZdBy/TXOFhf63+Fwlg/RONMtZH2Eb9l0DT xkS8OM6lWk+e5VV/sQd8Ck6Wc4nJnsiJxTvWFqIpr4pOxksyGiAlHtHcXgcNRUuDWVHx lQgw== X-Gm-Message-State: AJcUukdxhlwtotWYphPppGaf3B9iZ9PeLnotnpTLqGxs+SkZrkcAHfnx 6qYarJK50w/PNjvJ1adDS6q6w4TW X-Google-Smtp-Source: ALg8bN72AF/IAKGPiBxnJGSMHbnsOOZKdVbatqVO4aPt9J49mKrzCVobuVCC7furIFpnj2y3sMz14w== X-Received: by 2002:a17:902:9a02:: with SMTP id v2mr725269plp.180.1547503679459; Mon, 14 Jan 2019 14:07:59 -0800 (PST) Received: from dtor-ws ([2620:15c:202:201:3adc:b08c:7acc:b325]) by smtp.gmail.com with ESMTPSA id v89sm2593155pfj.164.2019.01.14.14.07.58 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 14 Jan 2019 14:07:58 -0800 (PST) Date: Mon, 14 Jan 2019 14:07:56 -0800 From: Dmitry Torokhov To: linux-input@vger.kernel.org Cc: Byoungyoung Lee , rydberg@bitmath.org, DaeRyong Jeong , syzkaller@googlegroups.com, Peter Hutterer , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Input: uinput - fix undefined behavior in uinput_validate_absinfo() Message-ID: <20190114220756.GF117329@dtor-ws> References: <20190114220448.GA241112@dtor-ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190114220448.GA241112@dtor-ws> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 14, 2019 at 02:04:48PM -0800, Dmitry Torokhov wrote: > An integer overflow may arise in uinput_validate_absinfo() if "max - min" > can't be represented by an "int". We should check for overflow before > trying to use the result. > > Reported-by: Kyungtae Kim > Cc: stable@vger.kernel.org > Signed-off-by: Dmitry Torokhov > --- > drivers/input/misc/uinput.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c > index 8ec483e8688b..26ec603fe220 100644 > --- a/drivers/input/misc/uinput.c > +++ b/drivers/input/misc/uinput.c > @@ -39,6 +39,7 @@ > #include > #include > #include > +#include > #include > #include "../input-compat.h" > > @@ -405,7 +406,7 @@ static int uinput_open(struct inode *inode, struct file *file) > static int uinput_validate_absinfo(struct input_dev *dev, unsigned int code, > const struct input_absinfo *abs) > { > - int min, max; > + int min, max, range; > > min = abs->minimum; > max = abs->maximum; > @@ -417,7 +418,7 @@ static int uinput_validate_absinfo(struct input_dev *dev, unsigned int code, > return -EINVAL; > } > > - if (abs->flat > max - min) { > + if (check_sub_overflow(max, min, &range) && abs->flat > range) { This should be !check_sub_overflow(...) of course. > printk(KERN_DEBUG > "%s: abs_flat #%02x out of range: %d (min:%d/max:%d)\n", > UINPUT_NAME, code, abs->flat, min, max); > -- > 2.20.1.97.g81188d93c3-goog > > > -- > Dmitry -- Dmitry