linux-kernel - Re: [PATCH] block: add check that partition length needs to be aligned with block size

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Date:   Mon, 26 Jun 2023 18:38:18 +0900
From:   Damien Le Moal <dlemoal@...nel.org>
To:     Min Li <min15.li@...sung.com>, axboe@...nel.dk,
        willy@...radead.org, hch@....de, gregkh@...uxfoundation.org
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] block: add check that partition length needs to be
 aligned with block size

On 6/27/23 02:10, Min Li wrote:
> Before calling add partition or resize partition, there is no check
> on whether the length is aligned with the logical block size.
> If the logical block size of the disk is larger than 512 bytes,
> then the partition size maybe not the multiple of the logical block size,
> and when the last sector is read, bio_truncate() will adjust the bio size,
> resulting in an IO error if the size of the read command is smaller than
> the logical block size.If integrity data is supported, this will also
> result in a null pointer dereference when calling bio_integrity_free.
> 
> Signed-off-by: Min Li <min15.li@...sung.com>
> ---
>  block/ioctl.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/block/ioctl.c b/block/ioctl.c
> index 9c5f637ff153..aa95b5561169 100644
> --- a/block/ioctl.c
> +++ b/block/ioctl.c
> @@ -35,6 +35,9 @@ static int blkpg_do_ioctl(struct block_device *bdev,
>  
>  	start = p.start >> SECTOR_SHIFT;
>  	length = p.length >> SECTOR_SHIFT;
> +	/*check if length is aligned to blocksize*/

Please add a space after /* and before */.

> +	if (p.length & (bdev_logical_block_size(bdev) - 1))
> +		return -EINVAL;

I would move this check before the "start = ...;" And while at it, I would also
move the check for p.start being aligned out of the "case BLKPG_ADD_PARTITION:"
together with this length alignment check. The p.start check is not needed for
BLKPG_RESIZE_PARTITION, but it will not hurt either.

>  
>  	switch (op) {
>  	case BLKPG_ADD_PARTITION:

-- 
Damien Le Moal
Western Digital Research