From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1752831AbdKHP6B (ORCPT <rfc822;w@1wt.eu>);
        Wed, 8 Nov 2017 10:58:01 -0500
Received: from youngberry.canonical.com ([91.189.89.112]:35141 "EHLO
        youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1752608AbdKHP57 (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 8 Nov 2017 10:57:59 -0500
Subject: NAK: [PATCH][mtd-next] mtd: sharpslpart: fix overflow on block_adr
 calculation
From: Colin Ian King <colin.king@canonical.com>
To: David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        Boris Brezillon <boris.brezillon@free-electrons.com>,
        Marek Vasut <marek.vasut@gmail.com>,
        Richard Weinberger <richard@nod.at>,
        Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
        Andrea Adami <andrea.adami@gmail.com>, linux-mtd@lists.infradead.org
Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20171108154649.30096-1-colin.king@canonical.com>
Message-ID: <c69cae0f-0490-20b7-9706-78d2ef2d3c73@canonical.com>
Date: Wed, 8 Nov 2017 15:57:57 +0000
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.4.0
MIME-Version: 1.0
In-Reply-To: <20171108154649.30096-1-colin.king@canonical.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 08/11/17 15:46, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Multiplying block_num and mtd->erasesize may potentially overflow
> as they are both unsigned ints and so the multiplication is evaluated
> in unsigned int arithmetic .  Cast block_adr to off_t to ensure
> multiplication is off_t sized to avoid any potential overflow.
> 
> Detected by CoverityScan, CID#1461264 ("Unintentional integer overflow")
> 
> Fixes: fff1e32a50c0 ("mtd: sharpslpart: Add sharpslpart partition parser")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/mtd/parsers/sharpslpart.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/parsers/sharpslpart.c b/drivers/mtd/parsers/sharpslpart.c
> index 5fe0079ea5ed..b1d97aa3bac4 100644
> --- a/drivers/mtd/parsers/sharpslpart.c
> +++ b/drivers/mtd/parsers/sharpslpart.c
> @@ -244,7 +244,7 @@ static int sharpsl_nand_read_laddr(struct mtd_info *mtd,
>  		return -EINVAL;
>  
>  	block_num = ftl->log2phy[log_num];
> -	block_adr = block_num * mtd->erasesize;
> +	block_adr = (loff_t)block_num * mtd->erasesize;
>  	block_ofs = mtd_mod_by_eb((u32)from, mtd);
>  
>  	err = mtd_read(mtd, block_adr + block_ofs, len, &retlen, buf);
> 

Sorry, ignore this, there is another place that does this that needs
some attention. I'll sent V2 shortly.