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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/53959/
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Review request for Ambari, Laszlo Puskas, Oliver Szabo, and Sebastian Toader.


Bugs: AMBARI-18938
    https://issues.apache.org/jira/browse/AMBARI-18938


Repository: ambari


Description
-------

When authenticating using LDAP where the LDAP server is a Centrify LDAP proxy, 
a `NullPointerException` is being thrown due to unexpected missing LDAP user 
object attributes. 

```
10 Nov 2016 08:23:38,789 ERROR [ambari-client-thread-25] 
AmbariLdapBindAuthenticator:95 - Caught exception
java.lang.NullPointerException
        at 
org.apache.ambari.server.security.authorization.AmbariLdapBindAuthenticator.authenticate(AmbariLdapBindAuthenticator.java:83)
        at 
org.springframework.security.ldap.authentication.LdapAuthenticationProvider.doAuthentication(LdapAuthenticationProvider.java:178)
        at 
org.springframework.security.ldap.authentication.AbstractLdapAuthenticationProvider.authenticate(AbstractLdapAuthenticationProvider.java:61)
        at 
org.apache.ambari.server.security.authorization.AmbariLdapAuthenticationProvider.authenticate(AmbariLdapAuthenticationProvider.java:73)
        at 
org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:156)
        at 
org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:168)
        at 
org.apache.ambari.server.security.authentication.AmbariAuthenticationFilter.doFilter(AmbariAuthenticationFilter.java:88)
        at 
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at 
org.apache.ambari.server.security.authorization.AmbariUserAuthorizationFilter.doFilter(AmbariUserAuthorizationFilter.java:91)
        at 
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at 
org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
        at 
org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
        at 
org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
        at 
org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
        at 
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
        at 
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
        at 
org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1478)
        at 
org.apache.ambari.server.api.MethodOverrideFilter.doFilter(MethodOverrideFilter.java:72)
        at 
org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1478)
        at 
org.apache.ambari.server.api.AmbariPersistFilter.doFilter(AmbariPersistFilter.java:47)
        at 
org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1478)
        at 
org.apache.ambari.server.security.AbstractSecurityHeaderFilter.doFilter(AbstractSecurityHeaderFilter.java:109)
        at 
org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1478)
        at 
org.eclipse.jetty.servlets.UserAgentFilter.doFilter(UserAgentFilter.java:82)
        at org.eclipse.jetty.servlets.GzipFilter.doFilter(GzipFilter.java:294)
        at 
org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1478)
        at 
org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:499)
        at 
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137)
        at 
org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:557)
        at 
org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:231)
        at 
org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1086)
        at 
org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:427)
        at 
org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:193)
        at 
org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1020)
        at 
org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135)
        at 
org.apache.ambari.server.controller.AmbariHandlerList.processHandlers(AmbariHandlerList.java:212)
        at 
org.apache.ambari.server.controller.AmbariHandlerList.processHandlers(AmbariHandlerList.java:201)
        at 
org.apache.ambari.server.controller.AmbariHandlerList.handle(AmbariHandlerList.java:139)
        at 
org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:116)
        at org.eclipse.jetty.server.Server.handle(Server.java:370)
        at 
org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:494)
        at 
org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpConnection.java:973)
        at 
org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplete(AbstractHttpConnection.java:1035)
        at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:641)
        at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:231)
        at 
org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:82)
        at 
org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:696)
        at 
org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:53)
        at 
org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:608)
        at 
org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:543)
        at java.lang.Thread.run(Thread.java:745)
```

# Cause
The cause for this `NPE` is related to missing data from the attribute search 
request made to a Centrify LDAP proxy after a bind has occurred.  Since the 
query filter at this point is "`objectClass=*`", the Centrify LDAP proxy does 
not have enough data to determine what information to return to the caller.  
However, the filter was something like "`objectClass=posixAccount`", it will be 
able to build a set of attributes to return to the caller since it would 
determine that the call wants data for a specific _profile_.

This can be seen by the following {{tcpdump}} entry:
```
LDAPMessage searchRequest(2) "uid=user1,ou=people,ou=dev,dc=apache,dc=org" 
baseObject
    messageID: 2
    protocolOp: searchRequest (3)
        searchRequest
            baseObject: uid=user1,ou=people,ou=dev,dc=apache,dc=org
            scope: baseObject (0)
            derefAliases: derefAlways (3)
            sizeLimit: 0
            timeLimit: 0
            typesOnly: False
            Filter: (objectClass=*)
            attributes: 0 items
    [Response In: 2]
    controls: 1 item
```

Note the filter line above: *`Filter: (objectClass=*)`*

>From the Centrify LDAP proxy logs, the following lines can be seen showing 
>that no mapping is avaialbe:

```
Nov  8 12:13:45 host1 slapd: cdc search start with filterstr: (objectClass=*)
Nov  8 12:13:45 host1 slapd: cdc search: objectType =  ( is mapped to NONE)
Nov  8 12:13:45 host1 slapd: cdc search after translation filter = 
(objectClass=*)
```

This search filter is hardcoded in `com.sun.jndi.ldap.LdapCtx` as seen in 
http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/6-b14/com/sun/jndi/ldap/LdapCtx.java#1308.

This code is invoked from the Spring LDAP library after attempting to 
authenticate using the Spring 
org.springframework.security.ldap.authentication.BindAuthenticator class. 

# Solution
To solve this, Ambari should avoid using 
`org.springframework.security.ldap.authentication.BindAuthenticator` to 
authenticate users via LDAP so that more control can be had over when and how 
user attributes are obtained.


Diffs
-----

  
ambari-server/src/main/java/org/apache/ambari/server/security/authorization/AmbariLdapAuthenticationProvider.java
 6905757 
  
ambari-server/src/main/java/org/apache/ambari/server/security/authorization/AmbariLdapBindAuthenticator.java
 b34ef6a 
  
ambari-server/src/test/java/org/apache/ambari/server/security/authorization/AmbariLdapBindAuthenticatorTest.java
 cea4b66 

Diff: https://reviews.apache.org/r/53959/diff/


Testing
-------

Manually tested against various LDAP servers.


Thanks,

Robert Levas

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