2023-12-19 08:02:46

by Li Nan

Subject: [PATCH] block: add check of 'minors' and 'first_minor' in device_add_disk()

From: Li Nan <[email protected]>

'first_minor' represents the starting minor number of disks, and
'minors' represents the number of partitions in the device. Neither
of them can be greater than MINORMASK + 1.

Commit e338924bd05d ("block: check minor range in device_add_disk()")
only added the check of 'first_minor + minors'. However, their sum might
be less than MINORMASK but their values are wrong. Complete the checks now.

Fixes: e338924bd05d ("block: check minor range in device_add_disk()")
Signed-off-by: Li Nan <[email protected]>
---
block/genhd.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/genhd.c b/block/genhd.c
index c9d06f72c587..551b5693ebd5 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -432,7 +432,9 @@ int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
DISK_MAX_PARTS);
disk->minors = DISK_MAX_PARTS;
}
- if (disk->first_minor + disk->minors > MINORMASK + 1)
+ if (disk->first_minor > MINORMASK ||
+ disk->minors > MINORMASK + 1 ||
+ disk->first_minor + disk->minors > MINORMASK + 1)
goto out_exit_elevator;
} else {
if (WARN_ON(disk->minors))
--
2.39.2

2023-12-19 12:11:29

by Christoph Hellwig

Subject: Re: [PATCH] block: add check of 'minors' and 'first_minor' in device_add_disk()

Looks good:

Reviewed-by: Christoph Hellwig <[email protected]>

2023-12-19 15:24:01

by Jens Axboe

Subject: Re: [PATCH] block: add check of 'minors' and 'first_minor' in device_add_disk()

On Tue, 19 Dec 2023 15:59:42 +0800, [email protected] wrote:
> 'first_minor' represents the starting minor number of disks, and
> 'minors' represents the number of partitions in the device. Neither
> of them can be greater than MINORMASK + 1.
>
> Commit e338924bd05d ("block: check minor range in device_add_disk()")
> only added the check of 'first_minor + minors'. However, their sum might
> be less than MINORMASK but their values are wrong. Complete the checks now.
>
> [...]

Applied, thanks!

[1/1] block: add check of 'minors' and 'first_minor' in device_add_disk()
commit: 4c434392c4777881d01beada6701eff8c76b43fe

Best regards,
--
Jens Axboe