[HDFS-13668] FSPermissionChecker may throws AIOOE when check inode permission

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.1.0, 2.10.0, 2.7.7
• Fix Version/s: 3.2.0, 3.0.4, 3.1.2
• Component/s: namenode
• Hadoop Flags: Reviewed
• Assignee: Xiaoqiao He
• Reporter: Xiaoqiao He
• Created: 10/Jun/18 06:39
• Updated: 02/Oct/19 17:15
• Resolved: 13/Aug/18 09:47

Description

FSPermissionChecker may throw ArrayIndexOutOfBoundsException:0 when check if has permission, since it only check inode's aclFeature if null or not but not check it's entry size. When it meets aclFeature not null but it's entry size equal to 0, it will throw AIOOE.

private boolean hasPermission(INodeAttributes inode, FsAction access) {
  ......
  final AclFeature aclFeature = inode.getAclFeature();
  if (aclFeature != null) {
    // It's possible that the inode has a default ACL but no access ACL.
    int firstEntry = aclFeature.getEntryAt(0);
    if (AclEntryStatusFormat.getScope(firstEntry) == AclEntryScope.ACCESS) {
      return hasAclPermission(inode, access, mode, aclFeature);
    }
  }
  ......
}

Actually if use default INodeAttributeProvider, it can ensure that when inode's aclFeature is not null and it's entry size also will be greater than 0, but INodeAttributeProvider is a public interface, we could not ensure external implement (e.g. Apache Sentry, Apache Ranger) also has the similar constraint.