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block: check minor range in device_add_disk()

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[ Upstream commit e338924bd05d6e71574bc13e310c89e10e49a8a5 ]

ioctl(fd, LOOP_CTL_ADD, 1048576) causes

  sysfs: cannot create duplicate filename '/dev/block/7:0'

message because such request is treated as if ioctl(fd, LOOP_CTL_ADD, 0)
due to MINORMASK == 1048575. Verify that all minor numbers for that device
fit in the minor range.

Reported-by: wangyangbo <wangyangbo@uniontech.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/b1b19379-23ee-5379-0eb5-94bf5f79f1b4@i-love.sakura.ne.jp
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Tetsuo Handa 2021-12-17 23:51:25 +09:00 committed by Greg Kroah-Hartman
parent 892805138c
commit f75868e020
1 changed files with 2 additions and 0 deletions
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2
block/genhd.c
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@ -420,6 +420,8 @@ int 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)
return -EINVAL;
} else {
if (WARN_ON(disk->minors))
return -EINVAL;