linux-kernel - Re: [PATCH] block: move capacity validation to blkpg_do

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Date: Tue, 5 Mar 2024 14:24:04 +0800
From: Li Lingfeng <lilingfeng@...weicloud.com>
To: Damien Le Moal <dlemoal@...nel.org>, axboe@...nel.dk, min15.li@...sung.com
Cc: linux-block@...r.kernel.org, linux-kernel@...r.kernel.org, hch@....de,
 yangerkun@...wei.com, yukuai1@...weicloud.com, houtao1@...wei.com,
 yi.zhang@...wei.com
Subject: Re: [PATCH] block: move capacity validation to blkpg_do_ioctl()


在 2024/3/5 12:30, Damien Le Moal 写道:
> On 3/5/24 12:21, Li Lingfeng wrote:
>> From: Li Lingfeng <lilingfeng3@...wei.com>
>>
>> Commit 6d4e80db4ebe ("block: add capacity validation in
>> bdev_add_partition()") add check of partition's start and end sectors to
>> prevent exceeding the size of the disk when adding partitions. However,
>> there is still no check for resizing partitions now.
>> Move the check to blkpg_do_ioctl() to cover resizing partitions.
>>
>> Signed-off-by: Li Lingfeng <lilingfeng3@...wei.com>
>> ---
>>   block/ioctl.c           |  9 ++++++++-
>>   block/partitions/core.c | 11 -----------
>>   2 files changed, 8 insertions(+), 12 deletions(-)
>>
>> diff --git a/block/ioctl.c b/block/ioctl.c
>> index 438f79c564cf..de0cc0d215c6 100644
>> --- a/block/ioctl.c
>> +++ b/block/ioctl.c
>> @@ -18,7 +18,7 @@ static int blkpg_do_ioctl(struct block_device *bdev,
>>   {
>>   	struct gendisk *disk = bdev->bd_disk;
>>   	struct blkpg_partition p;
>> -	sector_t start, length;
>> +	sector_t start, length, capacity, end;
>>   
>>   	if (!capable(CAP_SYS_ADMIN))
>>   		return -EACCES;
>> @@ -41,6 +41,13 @@ static int blkpg_do_ioctl(struct block_device *bdev,
>>   
>>   	start = p.start >> SECTOR_SHIFT;
>>   	length = p.length >> SECTOR_SHIFT;
>> +	capacity = get_capacity(disk);
>> +
>> +	if (check_add_overflow(start, length, &end))
>> +		return -EINVAL;
>> +
>> +	if (start >= capacity || end > capacity)
>> +		return -EINVAL;
>>   
>>   	switch (op) {
>>   	case BLKPG_ADD_PARTITION:
>> diff --git a/block/partitions/core.c b/block/partitions/core.c
>> index 5f5ed5c75f04..b11e88c82c8c 100644
>> --- a/block/partitions/core.c
>> +++ b/block/partitions/core.c
>> @@ -419,21 +419,10 @@ static bool partition_overlaps(struct gendisk *disk, sector_t start,
>>   int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
>>   		sector_t length)
>>   {
>> -	sector_t capacity = get_capacity(disk), end;
>>   	struct block_device *part;
>>   	int ret;
>>   
>>   	mutex_lock(&disk->open_mutex);
>> -	if (check_add_overflow(start, length, &end)) {
>> -		ret = -EINVAL;
>> -		goto out;
>> -	}
>> -
>> -	if (start >= capacity || end > capacity) {
>> -		ret = -EINVAL;
>> -		goto out;
>> -	}
>> -
> Why do you remove this ? The check will not be done when *existing* partitions
I'm sorry, I didn't quite understand your point. The function 
bdev_add_partition() is only called within blkpg_do_ioctl(). I simply 
moved the check to a different location, but did not remove it entirely.
> are added. To do the check when *creating* a partition, make this code a helper
> and call that helper function here and from blkpg_do_ioctl() as well.
Do you mean call the helper function in blk_add_partition() and 
blkpg_do_ioctl()?
>
>>   	if (!disk_live(disk)) {
>>   		ret = -ENXIO;
>>   		goto out;