RFR: 8362268: NPE thrown from SASL GSSAPI impl when TLS is used with QOP auth-int against Active Directory

[Jaikiran Pai]

On Mon, 9 Feb 2026 16:40:37 GMT, Daniel Fuchs <dfuchs at openjdk.org> wrote:

>> Can I please get a review of this change which proposes to fix the issue reported in https://bugs.openjdk.org/browse/JDK-8362268?
>> 
>> The underlying issue here is simple - A `javax.naming.Context` for LDAP is backed by a JDK internal `com.sun.jndi.ldap.LdapCtx` instance. Each `LdapCtx` uses a `com.sun.jndi.ldap.LdapClient` instance to do the LDAP operations. Each `LdapClient` further uses a `com.sun.jndi.ldap.Connection` instance. Each `Connection` instance uses a `Socket` and the socket's `InputStream` and `OutputStream` to read/write LDAP messages from/to a LDAP server. Each `Connection` instance spawns a `Thread` to read (over the InputStream) and queue incoming messages from the LDAP server.
>> 
>> When a LDAP backed `javax.naming.Context` initiates an operation, for example a `Context.lookup()`, then internally the LdapCtx initiates a LDAP request over the Connection's `OutputStream` and then waits for a LDAP response to arrive. In the issue reported here, it so happens that while reading over the `Connection`'s `InputStream`, the `InputStream.read()` raises an `IOException` (for whatever reason). That `IOException` rightly initiates the close of the `Connection` instance. Closing a `Connection` instance involves queuing a marker response for all waiting thread(s) to notice and raise an IOException, which they can ulimately propagate as a `NamingException` to the application. Additionally, the closing of the `Connection` also closes the `InputStream` and `OutputStream` of that `Connection`.
>> 
>> When a thread that was waiting for a LDAP response, in LdapCtx, wakes up due to an IOException, it attempts to send a "abandon request" LDAP message over the `Connection`, so that the server knows that the client has abandoned the request. Since the Connection and its Input/OutputStream(s) are already closed, trying to write a message over the OutputStream can/will lead to an exception. The implementation of `Connection.abandonRequest(LdapRequest ldr, Control[] reqCtls)` which is where this code resides, guards against such exceptions by catching and ignoring an `IOException` from an `OutputStream.write(...)/flush()` call.
>> 
>> Although `OutputStream.write(...)` is specified to throw an IOException if that stream is already closed, not all implementations adhere to that specification. For example, `java.io.BufferedOutputStream` does not throw any exception when `write(...)` is invoked on a closed `OutputStream`. Incidentally, the `Connection` instance's `Outp...
>
> src/java.naming/share/classes/com/sun/jndi/ldap/Connection.java line 554:
> 
>> 552:                     // on a (closed) stream of a connection that can no longer be used.
>> 553:                     return;
>> 554:                 }
> 
> I am not sure this is the right test. If I am not mistaken, this means that "abandon request" will never be sent to the server, ever, since the flag is set to false in cleanup() before abandonning requests. 
> Should we instead test whether the socket output is closed here?

That's a good point. Like you note, I think we will have to check a different state here instead of `!useable`. I'll update the PR tomorrow after a more closer look.

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PR Review Comment: https://git.openjdk.org/jdk/pull/29638#discussion_r2783629638