Commit 4181c30a authored Jun 05, 2023 by Zhong Jinghua Committed by Greg Kroah-Hartman Jul 27, 2023

nbd: Add the maximum limit of allocated index in nbd_dev_add



[ Upstream commit f12bc113ce904777fd6ca003b473b427782b3dde ]

If the index allocated by idr_alloc greater than MINORMASK >> part_shift,
the device number will overflow, resulting in failure to create a block
device.

Fix it by imiting the size of the max allocation.

Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230605122159.2134384-1-zhongjinghua@huaweicloud.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent d4f1cd9b

drivers/block/nbd.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1708,7 +1708,8 @@ static int nbd_dev_add(int index)
		if (err == -ENOSPC)
		err = -EEXIST;
		} else {
		err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
		err = idr_alloc(&nbd_index_idr, nbd, 0,
		(MINORMASK >> part_shift) + 1, GFP_KERNEL);
		if (err >= 0)
		index = err;
		}