From 976da4aa6126aefd775b7c223c71e29d1207bf10 Mon Sep 17 00:00:00 2001
From: Matthew Swift <matthew.swift@forgerock.com>
Date: Wed, 11 Dec 2013 17:17:53 +0000
Subject: [PATCH] Fix OPENDJ-1247: Client side timeouts do not cancel bind or startTLS requests properly

---
 opendj-ldap-sdk/src/main/java/com/forgerock/opendj/ldap/LDAPConnection.java |  133 +++++++++++++++++++++++++++++++++----------
 1 files changed, 101 insertions(+), 32 deletions(-)

diff --git a/opendj-ldap-sdk/src/main/java/com/forgerock/opendj/ldap/LDAPConnection.java b/opendj-ldap-sdk/src/main/java/com/forgerock/opendj/ldap/LDAPConnection.java
index 68c95ed..8829372 100644
--- a/opendj-ldap-sdk/src/main/java/com/forgerock/opendj/ldap/LDAPConnection.java
+++ b/opendj-ldap-sdk/src/main/java/com/forgerock/opendj/ldap/LDAPConnection.java
@@ -28,7 +28,9 @@
 package com.forgerock.opendj.ldap;
 
 import static com.forgerock.opendj.util.StaticUtils.DEBUG_LOG;
+import static org.forgerock.opendj.ldap.CoreMessages.*;
 import static org.forgerock.opendj.ldap.ErrorResultException.newErrorResult;
+import static org.forgerock.opendj.ldap.requests.Requests.newAbandonRequest;
 
 import java.io.IOException;
 import java.net.InetSocketAddress;
@@ -65,7 +67,6 @@
 import org.forgerock.opendj.ldap.requests.GenericBindRequest;
 import org.forgerock.opendj.ldap.requests.ModifyDNRequest;
 import org.forgerock.opendj.ldap.requests.ModifyRequest;
-import org.forgerock.opendj.ldap.requests.Requests;
 import org.forgerock.opendj.ldap.requests.SearchRequest;
 import org.forgerock.opendj.ldap.requests.StartTLSExtendedRequest;
 import org.forgerock.opendj.ldap.requests.UnbindRequest;
@@ -128,40 +129,64 @@
 
     @Override
     public FutureResult<Void> abandonAsync(final AbandonRequest request) {
-        final AbstractLDAPFutureResultImpl<?> pendingRequest;
-        final int messageID = nextMsgID.getAndIncrement();
+        /*
+         * Need to be careful here since both abandonAsync and Future.cancel can
+         * be called separately by the client application. Therefore
+         * future.cancel() should abandon the request, and abandonAsync should
+         * cancel the future. In addition, bind or StartTLS requests cannot be
+         * abandoned.
+         */
         try {
             synchronized (stateLock) {
                 checkConnectionIsValid();
-                checkBindOrStartTLSInProgress();
-                // Remove the future associated with the request to be abandoned.
-                pendingRequest = pendingRequests.remove(request.getRequestID());
-            }
-            if (pendingRequest == null) {
                 /*
-                 * There has never been a request with the specified message ID
-                 * or the response has already been received and handled. We can
-                 * ignore this abandon request.
+                 * If there is a bind or startTLS in progress then it must be
+                 * this request which is being abandoned. The following check
+                 * will prevent it from happening.
                  */
-
-                // Message ID will be -1 since no request was sent.
-                return new CompletedFutureResult<Void>((Void) null);
-            }
-            pendingRequest.cancel(false);
-            try {
-                final ASN1BufferWriter asn1Writer = ASN1BufferWriter.getWriter();
-                try {
-                    ldapWriter.abandonRequest(asn1Writer, messageID, request);
-                    connection.write(asn1Writer.getBuffer(), null);
-                    return new CompletedFutureResult<Void>((Void) null, messageID);
-                } finally {
-                    asn1Writer.recycle();
-                }
-            } catch (final IOException e) {
-                throw adaptRequestIOException(e);
+                checkBindOrStartTLSInProgress();
             }
         } catch (final ErrorResultException e) {
-            return new CompletedFutureResult<Void>(e, messageID);
+            return new CompletedFutureResult<Void>(e);
+        }
+
+        // Remove the future associated with the request to be abandoned.
+        final AbstractLDAPFutureResultImpl<?> pendingRequest =
+                pendingRequests.remove(request.getRequestID());
+        if (pendingRequest == null) {
+            /*
+             * There has never been a request with the specified message ID or
+             * the response has already been received and handled. We can ignore
+             * this abandon request.
+             */
+            return new CompletedFutureResult<Void>((Void) null);
+        }
+
+        /*
+         * This will cancel the future, but will also recursively invoke this
+         * method. Since the pending request has been removed, there is no risk
+         * of an infinite loop.
+         */
+        pendingRequest.cancel(false);
+
+        /*
+         * FIXME: there's a potential race condition here if a bind or startTLS
+         * is initiated just after we removed the pending request.
+         */
+        return sendAbandonRequest(request);
+    }
+
+    private FutureResult<Void> sendAbandonRequest(final AbandonRequest request) {
+        final ASN1BufferWriter asn1Writer = ASN1BufferWriter.getWriter();
+        try {
+            final int messageID = nextMsgID.getAndIncrement();
+            ldapWriter.abandonRequest(asn1Writer, messageID, request);
+            connection.write(asn1Writer.getBuffer(), null);
+            return new CompletedFutureResult<Void>((Void) null, messageID);
+        } catch (final IOException e) {
+            return new CompletedFutureResult<Void>(adaptRequestIOException(e));
+        } finally {
+            asn1Writer.recycle();
         }
     }
 
@@ -557,10 +582,54 @@
                 if (future != null && future.checkForTimeout()) {
                     final long diff = (future.getTimestamp() + timeout) - currentTime;
                     if (diff <= 0 && pendingRequests.remove(requestID) != null) {
-                        DEBUG_LOG.fine("Cancelling expired future result: " + future);
-                        final Result result = Responses.newResult(ResultCode.CLIENT_SIDE_TIMEOUT);
-                        future.adaptErrorResult(result);
-                        abandonAsync(Requests.newAbandonRequest(future.getRequestID()));
+                        if (future.isBindOrStartTLS()) {
+                            /*
+                             * No other operations can be performed while a bind
+                             * or StartTLS request is active, so we cannot time
+                             * out the request. We therefore have a choice:
+                             * either ignore timeouts for these operations, or
+                             * enforce them but doing so requires invalidating
+                             * the connection. We'll do the latter, since
+                             * ignoring timeouts could cause the application to
+                             * hang.
+                             */
+                            DEBUG_LOG.fine("Failing bind or StartTLS request due to timeout "
+                                    + "(connection will be invalidated): " + future);
+                            final Result result =
+                                    Responses.newResult(ResultCode.CLIENT_SIDE_TIMEOUT)
+                                            .setDiagnosticMessage(
+                                                    LDAP_CONNECTION_BIND_OR_START_TLS_REQUEST_TIMEOUT
+                                                            .get(timeout).toString());
+                            future.adaptErrorResult(result);
+
+                            // Fail the connection.
+                            final Result errorResult =
+                                    Responses.newResult(ResultCode.CLIENT_SIDE_TIMEOUT)
+                                            .setDiagnosticMessage(
+                                                    LDAP_CONNECTION_BIND_OR_START_TLS_CONNECTION_TIMEOUT
+                                                            .get(timeout).toString());
+                            connectionErrorOccurred(errorResult);
+                        } else {
+                            DEBUG_LOG.fine("Failing request due to timeout: " + future);
+                            final Result result =
+                                    Responses.newResult(ResultCode.CLIENT_SIDE_TIMEOUT)
+                                            .setDiagnosticMessage(
+                                                    LDAP_CONNECTION_REQUEST_TIMEOUT.get(timeout)
+                                                            .toString());
+                            future.adaptErrorResult(result);
+
+                            /*
+                             * FIXME: there's a potential race condition here if
+                             * a bind or startTLS is initiated just after we
+                             * check the boolean. It seems potentially even more
+                             * dangerous to send the abandon request while
+                             * holding the state lock, since a blocking write
+                             * could hang the application.
+                             */
+                            if (!bindOrStartTLSInProgress.get()) {
+                                sendAbandonRequest(newAbandonRequest(requestID));
+                            }
+                        }
                     } else {
                         delay = Math.min(delay, diff);
                     }

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