maillist inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6D1S7
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit?id=a240bc5c43130c6aa50831d7caaa02a1d84e1bce

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

Wear-leveling entry could be freed in error path, which may be accessed
again in eraseblk_count_seq_show(), for example:

__erase_worker                eraseblk_count_seq_show
                                wl = ubi->lookuptbl[*block_number]
				if (wl)
  wl_entry_destroy
    ubi->lookuptbl[e->pnum] = NULL
    kmem_cache_free(ubi_wl_entry_slab, e)
		                   erase_count = wl->ec  // UAF!

Wear-leveling entry updating/accessing in ubi->lookuptbl should be
protected by ubi->wl_lock, fix it by adding ubi->wl_lock to serialize
wl entry accessing between wl_entry_destroy() and
eraseblk_count_seq_show().

Fetch a reproducer in [Link].

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216305
Fixes: 7bccd12d ("ubi: Add debugfs file for tracking PEB state")
Fixes: 801c135c ("UBI: Unsorted Block Images")
Signed-off-by: NZhihao Cheng <chengzhihao1@huawei.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>
Reviewed-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NJialin Zhang <zhangjialin11@huawei.com>