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ASF GitHub Bot logged work on HADOOP-17467: ------------------------------------------- Author: ASF GitHub Bot Created on: 22/Jan/21 05:41 Start Date: 22/Jan/21 05:41 Worklog Time Spent: 10m Work Description: hadoop-yetus commented on pull request #2627: URL: https://github.com/apache/hadoop/pull/2627#issuecomment-763901913 ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org Issue Time Tracking ------------------- Worklog Id: (was: 539551) Time Spent: 2h (was: 1h 50m) > netgroup-user is not added to Groups.cache > ------------------------------------------ > > Key: HADOOP-17467 > URL: https://issues.apache.org/jira/browse/HADOOP-17467 > Project: Hadoop Common > Issue Type: Bug > Components: security > Reporter: Ahmed Hussein > Assignee: Ahmed Hussein > Priority: Major > Labels: pull-request-available > Time Spent: 2h > Remaining Estimate: 0h > > After the optimization in HADOOP-17079, {{JniBasedUnixGroupsNetgroupMapping}} > does not implement {{getGroupSet}}. > As a result, {{Groups.load()}} load the cache calling {{fetchGroupSet}} > which got > to the superclass {{JniBasedUnixGroupsMapping}}. > In other words, the groups mapping will never fetch from {{NetgroupCache}}. > This alters the behavior of the implementation. Is there a reason to bypass > loading. CC: [~xyao] > There is potential concurrency bug in the {{NetgroupCache}} implementation. > {{NetgroupCache}} is static. When ACL is built, its groups will be added to > the {{NetgroupCache}}. > A {{-refreshUserToGroupsMappings}} forces the cache to reload the users for > each group. > This is done by first getting the keys, clearing the cache, then finally > reloading the users for each group. > The problem that the three steps are not atomic. > Adding ACLs concurrently may take place between L80-L81 > ([JniBasedUnixGroupsNetgroupMapping#L79|https://github.com/apache/hadoop/blob/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/JniBasedUnixGroupsNetgroupMapping.java#L79]). > This results in the loss of the most recently added group. > Since group names are used in the JNI level, the users of that group won't > be retrieved. > {code:java} > 78 @Override > 79 public void cacheGroupsRefresh() throws IOException { > 80 List<String> groups = NetgroupCache.getNetgroupNames(); > 81 NetgroupCache.clear(); > 82 cacheGroupsAdd(groups); > 83 } > {code} > +Solution:+ > Refreshing {{NetgroupCache}} should not clear the cache keys. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org