[ZOOKEEPER-4565] Config watch path get truncated abnormally and fail chroot zookeeper client

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.6.3, 3.8.0, 3.7.1
• Fix Version/s: 3.9.0, 3.8.1, 3.7.2
• Component/s: java client
• Labels: pull-request-available
• Assignee: Kezhu Wang
• Reporter: Kezhu Wang
• Created: 29/Jun/22 11:06
• Updated: 04/Aug/23 11:28
• Resolved: 26/Jul/22 07:40

Description

ClientCnxn strips off chrootPath for notifications. This strip could break "/zookeeper/config" to illegal zookeeper path(aka. not start with "/") and fail zookeeper client due to index out of bound exception in PathParentIterator.next.

                // convert from a server path to a client path
                if (chrootPath != null) {
                    String serverPath = event.getPath();
                    if (serverPath.compareTo(chrootPath) == 0) {
                        event.setPath("/");
                    } else if (serverPath.length() > chrootPath.length()) {
                        event.setPath(serverPath.substring(chrootPath.length()));
                     } else {
                         LOG.warn("Got server path {} which is too short for chroot path {}.",
                             event.getPath(), chrootPath);
                     }
                }

I think we could make this strip similar to c client version sub_string and warns only for not "/zookeeper" nodes.

I found this issue in reproducing CURATOR-593 and CURATOR-611. And the consequences are different in 3.6.3 and before.

• Before 3.6.3(exclusive), watcher of getConfig will receive event with illegal path.
• After 3.6.3(inclusive), the client will disconnect due to exception from ZKWatchManager.addPersistentWatches which calls PathParentIterator.forAll. See codes from 3.6.3 and 3.7+.

Issue Links

• blocks: CURATOR-593 EnsembleTracker "configToConnectionString" method doesn't include zookeeper chroot
• blocks: CURATOR-611 EnsembleTracker not appending the chroot node when setting the new connection string
• is related to: ZOOKEEPER-4601 Define getConfig Watcher behavior in chroot ZooKeeper
• relates to: ZOOKEEPER-838 Chroot is an attribute of ClientCnxn
• links to: GitHub Pull Request #1899