Fix NULL pointer reference when closing an unused multi handle.

Author: linusnielsen

lib/multi.c

@@ -1773,10 +1773,12 @@ CURLMcode curl_multi_cleanup(CURLM *multi_handle)
     /* Close all the connections in the connection cache */
     close_all_connections(multi);
 
-    multi->closure_handle->dns.hostcache = multi->hostcache;
-    Curl_hostcache_clean(multi->closure_handle);
+    if(multi->closure_handle) {
+      multi->closure_handle->dns.hostcache = multi->hostcache;
+      Curl_hostcache_clean(multi->closure_handle);
 
-    Curl_close(multi->closure_handle);
+      Curl_close(multi->closure_handle);
+    }
     multi->closure_handle = NULL;
 
     Curl_hash_destroy(multi->sockhash);

tests/data/Makefile.am

@@ -94,6 +94,7 @@ test1387 test1388 test1389 test1390 test1391 test1392 test1393 \
 test1400 test1401 test1402 test1403 test1404 test1405 test1406 test1407 \
 test1408 test1409 test1410 test1411 test1412 test1413 \
 test1500 test1501 test1502 test1503 test1504 test1505 test1506 test1507 \
+test1508 \
 test2000 test2001 test2002 test2003 test2004 test2005 test2006 test2007 \
 test2008 test2009 test2010 test2011 test2012 test2013 test2014 test2015 \
 test2016 test2017 test2018 test2019 test2020 test2021 test2022 \

tests/data/test1508

@@ -0,0 +1,31 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+multi
+</keywords>
+</info>
+
+# Client-side
+<client>
+<server>
+none
+</server>
+<tool>
+lib1508
+</tool>
+ <name>
+Close a multi handle without using it
+ </name>
+ <command>
+http://%HOSTIP:%HTTPPORT/path/1508
+</command>
+</client>
+
+# Verify data after the test has been "shot"
+<verify>
+<file name="log/stdout1508" mode="text">
+We are done
+</file>
+</verify>
+</testcase>

tests/libtest/Makefile.inc

@@ -23,7 +23,7 @@ noinst_PROGRAMS = chkhostname libauthretry libntlmconnect \
                 lib582 lib583        lib585 lib586 lib587               \
   lib590 lib591                                    lib597 lib598 lib599 \
   \
-  lib1500 lib1501 lib1502 lib1503 lib1504 lib1505 lib1506 lib1507
+  lib1500 lib1501 lib1502 lib1503 lib1504 lib1505 lib1506 lib1507 lib1508
 
 chkhostname_SOURCES = chkhostname.c ../../lib/curl_gethostname.c
 chkhostname_LDADD = @CURL_NETWORK_LIBS@
@@ -316,3 +316,7 @@ lib1506_CPPFLAGS = $(AM_CPPFLAGS) -DLIB1506
 lib1507_SOURCES = lib1507.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 lib1507_LDADD = $(TESTUTIL_LIBS)
 lib1507_CPPFLAGS = $(AM_CPPFLAGS) -DLIB1507
+
+lib1508_SOURCES = lib1508.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
+lib1508_LDADD = $(TESTUTIL_LIBS)
+lib1508_CPPFLAGS = $(AM_CPPFLAGS) -DLIB1508

tests/libtest/lib1508.c

@@ -0,0 +1,49 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 2013, Linus Nielsen Feltzing <linus@haxx.se>
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at http://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+#include "test.h"
+
+#include "testutil.h"
+#include "warnless.h"
+#include "memdebug.h"
+
+int test(char *URL)
+{
+  int res = 0;
+  CURLM *m = NULL;
+
+  (void)URL;
+
+  global_init(CURL_GLOBAL_ALL);
+
+  multi_init(m);
+
+test_cleanup:
+
+  /* proper cleanup sequence - type PB */
+
+  curl_multi_cleanup(m);
+  curl_global_cleanup();
+
+  printf("We are done\n");
+
+  return res;
+}