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Geertjan Wielenga commented on NETBEANS-58: ------------------------------------------- Seems to be connected to this, i.e., would this solve it for you: https://github.com/apache/netbeans/pull/2 > NB IDE or NB Platform freeze on startup (proxy with Negotiate auth) > ------------------------------------------------------------------- > > Key: NETBEANS-58 > URL: https://issues.apache.org/jira/browse/NETBEANS-58 > Project: NetBeans > Issue Type: Bug > Components: platform - Proxy > Affects Versions: 8.2, 9.0, 11.0 > Environment: Primarily Windows. > Reporter: phansson > Priority: Critical > Attachments: NETBEANS-58-workaround1.diff, > image-2018-04-24-15-57-47-592.png, nb-freeze-dump.txt, netbeans.txt > > > When any network operation is performed, such as attempting to contact > NetBeans Update Center, the application (IDE or Platform) may freeze. Users > will typically experience this on startup. It was reported in old bug tracker > as [bug 248308|https://netbeans.org/bugzilla/show_bug.cgi?id=248308]. > The problem arises because of the fix JDK folks applied as a consequence of > the reported [JDK-8032832 > bug|https://bugs.openjdk.java.net/browse/JDK-8032832]. This fix wasn't very > clever IMO: it puts a lock on the classloader, thus introducing a range of > other problems, one of them being that NetNeans IDE or NetBeans Platform will > likely freeze on startup when it attempts a network operation. The fact that > their fix made things worse (while no doubt fixing the original issue) has > been reported as > [JDK-8068184|https://bugs.openjdk.java.net/browse/JDK-8068184]. > h3. WHEN DOES IT HAPPEN? > As the lock is introduced for authentication of type 'Negotiate' it of course > only happens if there's a network proxy on the path which uses this type of > authentication. Also known as SPNEGO. This form of authentication is in my > experience very common in corporate networks, in particular those that base > themselves on the Microsoft stack. But a person on Oracle's own internal > network, such as a JDK developer, is most likely not exposed to it. :-) > There's another condition for it to happen: The JRE runtime must be unable to > provide 'credentials' (a Kerberos token) to the network proxy on its own. > SPNEGO is really designed to be seamless and promptless. Support for it was > added in Java 6. But later on Microsoft tightened the desktop security around > obtaining the so-called 'session token' and the JDK folks were never able to > work around this (unlike the makers of Chrome, FF, Opera, etc). Therefore, in > real-life, SPNEGO in the JRE on Windows is no longer promptless: it will be > forced to ask the user for credentials, thus negating the idea of SPNEGO. It > is the prompting which causes the freeze. SPNEGO on Mac OS X and Linux is > most likely working just fine and the bug will never be experienced. > h3. HOW DO I KNOW IF I'M AFFECTED BY EXACTLY THIS BUG? > This bug in this ticket is characterized by the fact that you'll always be > able to find the following in your thread dump: > {noformat} > at > sun.net.www.protocol.http.NegotiateAuthentication.isSupported(NegotiateAuthentication.java:<lineno>) > - locked <OBJECTID> (a org.netbeans.ModuleManager$SystemClassLoader) > {noformat} > Note that the [Ctrl-Break > method|https://docs.oracle.com/javase/8/docs/technotes/guides/troubleshoot/tooldescr019.html] > of obtaining a thread dump is favoured over jstack and other methods. > h3. WHY DOES IT HAPPEN? > There will be a lock held on the classloader object when the JRE's registered > Authenticator is invoked. If the Authenticator does work on another thread, > that other thread has a need for some classloading and the current thread > needs to wait for the result of that thread, then bum!, there's a deadlock > between the two threads. This means the lock on the classloader will never be > released and it will ultimately affect other threads, such as the AWT > dispatch thread (aka Swing EDT) which will then also lock. Then you have what > the user experiences as a freeze. > The NB Platform's own Authenticator, {{NbAuthenticator}}, does exactly what I > described and will thus be triggering the deadlock. More precisely it will > happen when NbAuthenticator calls Keyring. Does this mean the NbAuthenticator > does something wrong? No, of course it doesn't. The real problem is the lock > on the classloader. It is actually virtually impossible to design an > Authenticator which doesn't trigger this problem. You cannot predict when > classloading is needed. In fact it is very likely to be needed when > application is still not "warm", i.e. during startup. > h3. WORKAROUNDS > *#1* > If on Windows: Setting the following registry key: > {{HKLM\System\CurrentControlSet\Control\Lsa\Kerberos\Parameters\allowtgtsessionkey}} > to {{true}} will allow the JRE to obtain the session key, thus the JDK's HTTP > classes will have no need to invoke Authenticator, thus deadlock will not > happen. But this registry key only has effect for users who are _not_ local > admins and since it is a HKLM such user will need to ask his administrator to > do this change. There's probably zero chance in a million that a corporate > network administrator will allow this change. After all, Microsoft introduced > the tightened security for a reason and the admin will rightly ask why only > the JRE needs this and not Chrome, IE, FF, Opera and so on? > *#2* > Convice the JDK folks that they've made a mess of it with this lock. I've > pursued this avenue too. I've done that on the JDK security-dev mailing list. > I've pointed to similar bug tickets for Eclipse IDE and IDEA and I got the > attention of Weijun Wang ("Max") of Oracle who promised he would look at it. > But to be honest the JDK people have a lot of other things on their plate and > a fix will take some time. > UPDATE 29-OCT-2017: To be fair to the JDK folks to issue only occurs with > NB's own classloaders. So the chance they'll fix it at the JDK end is > probably slim. > Link: > http://mail.openjdk.java.net/pipermail/security-dev/2017-August/016267.html > *#3* > Re-design the Authenticator in the Platform. As I cannot change the code in > NB itself, I've created a workaround as a plugin. The recipe is described in > [Comment 44|https://netbeans.org/bugzilla/show_bug.cgi?id=248308#c44] on the > original NB bug ticket. This is really a workaround, not a fix. It will > simply give up on attempting to obtain credentials if it discovers that it is > likely to be in this deadlock scenario. Thus it leaves the application with > no outbound network connectivity but it is still better than the freeze. It > also alerts the user to the situation using a bubble notification. > Links: > https://bitbucket.org/phansson/netbeansnetworkauthenticator > https://bitbucket.org/phansson/netbeansnetworkauthenticator/wiki/JDK-8068184%20Workaround > *#4* > It may help to set proxy username/password _explicitly_ in the NB's Options > panel. But this is not a solution I recommend. It means you must put your AD > password into NetBeans IDE Options. It will of course be static so once your > AD password changes then you must remember to change there as well. And for > the user to configure this, it requires that he can actually start the IDE or > Platform app in the first place ... which is often not the case because of > the freeze. > *#5* > Use a JRE prior to 8u20 or prior to 7u76. To most people this workaround is > unacceptable. > h3. CONCLUSION > IMHO #3 is the most attractive solution for now. It doesn't exclude the user > still doing #1 or #4 to get full benefit. The real solution is of course #2. > .. and the very best solution long term is if JDK would have same support for > SPNEGO on Windows as does 'regular' applications such as Chrome, FF, Opera, > IE, Edge, etc. Then we wouldn't have the problem in the first place. This has > been discussed intensively over the last 7-8 years but there's a somewhat > religious tug of war between Sun/Oracle and Microsoft on the matter. The > problem can be solved if the JDK would base itself on the Win32 SSPI api in > this area, rather than the long-time deprecated Win32 > LsaCallAuthenticationPackage API. We are getting slightly off topic here and > not appropriate for a bug ticket. :-) -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@netbeans.apache.org For additional commands, e-mail: commits-h...@netbeans.apache.org For further information about the NetBeans mailing lists, visit: https://cwiki.apache.org/confluence/display/NETBEANS/Mailing+lists