[MAPREDUCE-7346] [Gridmix] A potential divide by zero in AvgRecordFactory

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: contrib/gridmix
• Labels: gridmix pull-request-available security
• External issue URL: https://github.com/apache/hadoop/pull/3047
• Assignee: Unassigned
• Reporter: Yiyuan GUO
• Created: 20/May/21 02:39
• Updated: 25/May/21 10:50

Description

In the file gridmix/AvgRecordFactory.java, one of the class's constructor has the following code:

public AvgRecordFactory(long targetBytes, long targetRecords,
      Configuration conf, int minSpilledBytes) {
    this.targetBytes = targetBytes;
    this.targetRecords = targetRecords <= 0 && this.targetBytes >= 0
      ? Math.max(1,
          this.targetBytes / conf.getInt(GRIDMIX_MISSING_REC_SIZE, 64 * 1024))
      : targetRecords;
    final long tmp = this.targetBytes / this.targetRecords;
    ...
}

The check in the code targetRecords <= 0 && this.targetBytes >= 0 is not sufficient: when targetRecords == 0 && targetBytes < 0, we can bypass the protection checking and set this.targetRecords to zero, leading to a divide by zero problem when computing tmp.

 

Issue Links

• links to: GitHub Pull Request #3047