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Message-ID: <621fecd9-52ee-b5ba-6702-c283658096ef@kernel.org>
Date:   Thu, 15 Jun 2023 17:42:48 +0900
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Subject: Re: [PATCH] block: add capacity validation in bdev_add_partition()
Content-Language: en-US
To:     "min15.li" <min15.li@samsung.com>, axboe@kernel.dk,
        willy@infradead.org, hch@lst.de, gregkh@linuxfoundation.org,
        wsa@kernel.org, vkoul@kernel.org
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
References: <CGME20230615081227epcas5p40cd9cdf762fcaeedaa8cf8d92d425560@epcas5p4.samsung.com>
 <20230615160929.9240-1-min15.li@samsung.com>
From:   Damien Le Moal <dlemoal@kernel.org>
Organization: Western Digital Research
In-Reply-To: <20230615160929.9240-1-min15.li@samsung.com>
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On 6/16/23 01:09, min15.li wrote:
> In the function bdev_add_partition(),there is no check that the start
> and end sectors exceed the size of the disk before calling add_partition.
> When we call the block's ioctl interface directly to add a partition,
> and the capacity of the disk is set to 0 by driver,the command will
> continue to execute.
> 
> Signed-off-by: min15.li <min15.li@samsung.com>
> ---
>  block/partitions/core.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/block/partitions/core.c b/block/partitions/core.c
> index 49e0496ff23c..9806a804e1a4 100644
> --- a/block/partitions/core.c
> +++ b/block/partitions/core.c
> @@ -445,6 +445,12 @@ int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
>  		goto out;
>  	}
>  
> +	if (start >= get_capacity(disk) ||
> +		start + length > get_capacity(disk)) {

declaring:

	sector_t capacity = get_capacity(disk);

at the beginning of the function would make this check prettier and fit on one line.

> +		ret = -EINVAL;
> +		goto out;
> +	}
> +
>  	if (partition_overlaps(disk, start, length, -1)) {
>  		ret = -EBUSY;
>  		goto out;

-- 
Damien Le Moal
Western Digital Research