[HADOOP-17686] Avoid potential NPE by using Path#getParentPath API in hadoop-huaweicloud

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.4.0
• Component/s: fs
• Labels: pull-request-available
• Assignee: Viraj Jasani
• Reporter: Error Reporter
• Created: 07/May/21 03:54
• Updated: 12/May/21 01:36
• Resolved: 12/May/21 01:36

Description

Hello,
Our code analyses found a following potential NPE:

 

public Path getParent() {
    String path = uri.getPath();
    int lastSlash = path.lastIndexOf('/');
    int start = startPositionWithoutWindowsDrive(path);
    if ((path.length() == start) ||               // empty path
        (lastSlash == start && path.length() == start+1)) { // at root
      return null; <--- Null returned
    }

 

private static void getDirectories(final String key, final String sourceKey,
      final Set<String> directories) {
    Path p = new Path(key);
    Path sourcePath = new Path(sourceKey);
    // directory must add first
    if (key.endsWith("/") && p.compareTo(sourcePath) > 0) {
      directories.add(p.toString());
    }
    while (p.compareTo(sourcePath) > 0) {
      p = p.getParent(); <--- NPE
      if (p.isRoot() || p.compareTo(sourcePath) == 0) {
        break;
      }

Given a root path, it will lead to NPE at method getDirectories

 

Full trace:

 

1. Return null to caller
https://github.com/apache/hadoop/blob/f40e3eb0590f85bb42d2471992bf5d524628fdd6/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/Path.java#L432

2. Function getParent executes and returns
https://github.com/apache/hadoop/blob/f40e3eb0590f85bb42d2471992bf5d524628fdd6/hadoop-cloud-storage-project/hadoop-huaweicloud/src/main/java/org/apache/hadoop/fs/obs/OBSObjectBucketUtils.java#L875

3. The return value of function getParent is passed as the this pointer to function isRoot (the return value of function getParent can be null)
https://github.com/apache/hadoop/blob/f40e3eb0590f85bb42d2471992bf5d524628fdd6/hadoop-cloud-storage-project/hadoop-huaweicloud/src/main/java/org/apache/hadoop/fs/obs/OBSObjectBucketUtils.java#L876

Commit: f40e3eb0590f85bb42d2471992bf5d524628fdd6

Issue Links

• links to: GitHub Pull Request #2990