Commit b38c069e authored Nov 10, 2023 by Li Lingfeng Committed by openeuler-sync-bot Dec 04, 2023

nbd: fix uaf in nbd_open

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I81XCK



--------------------------------

Commit bd0c825c26c3 ("[Backport] nbd: use blk_mq_alloc_disk and
blk_cleanup_disk") cleans up disk by blk_cleanup_disk() and it won't set
disk->private_data as NULL as before. UAF may be triggered in nbd_open()
if someone tries to open nbd device right after nbd_put() since refcount
of nbd device is zero and private_data is not NULL.

Fixes: bd0c825c26c3 ("[Backport] nbd: use blk_mq_alloc_disk and blk_cleanup_disk")
Signed-off-by: Li Lingfeng <lilingfeng3@huawei.com>
Signed-off-by: Li Nan <linan122@huawei.com>
(cherry picked from commit 467373dd)

parent 2fda773f

drivers/block/nbd.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -229,6 +229,7 @@ static void nbd_dev_remove(struct nbd_device *nbd)

		if (disk) {
		del_gendisk(disk);
		disk->private_data = NULL;
		blk_cleanup_disk(disk);
		blk_mq_free_tag_set(&nbd->tag_set);
		}