[PATCH v2] block: add capacity validation in bdev_add_partition()

[PATCH v2] block: add capacity validation in bdev_add_partition()

[min15.li]

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.
v1->v2: check for overflows of the start + length value and put
the capacity check at the beginning of the function.

Signed-off-by: min15.li <min15.li@samsung.com>
---
 block/partitions/core.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index 49e0496ff23c..3546b43d5124 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -438,8 +438,20 @@ int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
 {
 	struct block_device *part;
 	int ret;
+	sector_t end;
+	sector_t capacity = get_capacity(disk);
 
 	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;
+	}
+
 	if (!disk_live(disk)) {
 		ret = -ENXIO;
 		goto out;
-- 
2.34.1

Re: [PATCH v2] block: add capacity validation in bdev_add_partition()

[Christoph Hellwig]

On Fri, Jun 16, 2023 at 11:05:57AM +0000, 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.
> v1->v2: check for overflows of the start + length value and put
> the capacity check at the beginning of the function.
> 
> Signed-off-by: min15.li <min15.li@samsung.com>
> ---
>  block/partitions/core.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/block/partitions/core.c b/block/partitions/core.c
> index 49e0496ff23c..3546b43d5124 100644
> --- a/block/partitions/core.c
> +++ b/block/partitions/core.c
> @@ -438,8 +438,20 @@ int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
>  {
>  	struct block_device *part;
>  	int ret;
> +	sector_t end;
> +	sector_t capacity = get_capacity(disk);

Very minor nitpick, but I think this would read nicer as:

+	sector_t capacity = get_capacity(disk), end;
  	struct block_device *part;
  	int ret;

Otherwise this looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

Re: [PATCH v2] block: add capacity validation in bdev_add_partition()

[Greg KH]

On Fri, Jun 16, 2023 at 11:05:57AM +0000, 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.
> v1->v2: check for overflows of the start + length value and put
> the capacity check at the beginning of the function.
> 
> Signed-off-by: min15.li <min15.li@samsung.com>

I doubt you sign documents as "min15.li", right? :)

Please fix.

You also forgot a "changes" list below the --- line saying what changed
from the previous submission.

thanks,

greg k-h