[jira] [Created] (HBASE-11194) [AccessController] issue with covering permission check in case of concurrent op on same row

["Anoop Sam John (JIRA)" <ji...@apache.org>]

Anoop Sam John created HBASE-11194:
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             Summary: [AccessController] issue with covering permission check in case of concurrent op on same row
                 Key: HBASE-11194
                 URL: https://issues.apache.org/jira/browse/HBASE-11194
             Project: HBase
          Issue Type: Bug
          Components: security
    Affects Versions: 0.98.0
            Reporter: Anoop Sam John
            Assignee: Anoop Sam John
             Fix For: 0.99.0, 0.98.3


The issue is the hook where we do check in which we have not acquired rowlock. Take case of delete, we do the check in the preDelete() hook. We do get the covering cells and check against their acls. At the point of the preDelete hook, we have not acquired the row lock on the deleting row.

Consider 2 parallel threads one doing put and other delete both dealing with same row.
Thread 1 acquired the rowlock and decided the TS  (HRS time) and doing the memstore write and HLog sync but the mvcc read point is NOT advanced. 
Thread 2 at same time, doing the delete of the row (Say with latest TS . The intent is to delete entire row) and in place of preDelete hook. There is no row locking happening at this point. As part of covering permission check, it doing a Get. But as said above, the put is not complete and the mvcc advance has not happened. So the Get won’t return the new cell.  It will return the old cells. And the check pass for the old cells.  Now suppose the new cell ACL is not matching for the deleting user.  But the cell was not read, the check has not happened.  So the ACL check will allow the user  to delete row..  The flow later comes to HRegion#doMiniBatchMutate() and try acquire row lock and by that time the Thread 1 op was over. So it will get lock and will add the delete tombstone.  As a result the cell, for which the deleting user has no acl right, also will get deleted.




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