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From "He Xiaoqiao (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HDFS-14305) Serial number in BlockTokenSecretManager could overlap between different namenodes
Date Sun, 24 Feb 2019 11:14:00 GMT

     [ https://issues.apache.org/jira/browse/HDFS-14305?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

He Xiaoqiao updated HDFS-14305:
-------------------------------
    Attachment: HDFS-14305.002.patch
        Status: Patch Available  (was: Open)

[~csun],[~xkrogen], [^HDFS-14305.002.patch] using 10 bits to identify index of NameNode in
the same namespace, and the remainder 22 bits auto-incr, which can cover <1024 namenodes
in one namespace and fix serial No. overlap about {{BlockTokenSecretManager}} with the previous
implementation without HDFS-6440. Please help to review at your convenience.

> Serial number in BlockTokenSecretManager could overlap between different namenodes
> ----------------------------------------------------------------------------------
>
>                 Key: HDFS-14305
>                 URL: https://issues.apache.org/jira/browse/HDFS-14305
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: security
>            Reporter: Chao Sun
>            Assignee: Chao Sun
>            Priority: Major
>         Attachments: HDFS-14305.001.patch, HDFS-14305.002.patch
>
>
> Currently, a {{BlockTokenSecretManager}} starts with a random integer as the initial
serial number, and then use this formula to rotate it:
> {code:java}
>     this.intRange = Integer.MAX_VALUE / numNNs;
>     this.nnRangeStart = intRange * nnIndex;
>     this.serialNo = (this.serialNo % intRange) + (nnRangeStart);
>  {code}
> while {{numNNs}} is the total number of NameNodes in the cluster, and {{nnIndex}} is
the index of the current NameNode specified in the configuration {{dfs.ha.namenodes.<nameservice>}}.
> However, with this approach, different NameNode could have overlapping ranges for serial
number. For simplicity, let's assume {{Integer.MAX_VALUE}} is 100, and we have 2 NameNodes
{{nn1}} and {{nn2}} in configuration. Then the ranges for these two are:
> {code}
> nn1 -> [-49, 49]
> nn2 -> [1, 99]
> {code}
> This is because the initial serial number could be any negative integer.
> Moreover, when the keys are updated, the serial number will again be updated with the
formula:
> {code}
> this.serialNo = (this.serialNo % intRange) + (nnRangeStart);
> {code}
> which means the new serial number could be updated to a range that belongs to a different
NameNode, thus increasing the chance of collision again.
> When the collision happens, DataNodes could overwrite an existing key which will cause
clients to fail because of {{InvalidToken}} error.



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