curl_easy_reset: reset the referer string

When CURLOPT_REFERER has been used, curl_easy_reset() did not properly
clear it.

Verified with the new test 598

Bug: http://curl.haxx.se/bug/view.cgi?id=3481551
Reported by: Michael Day

lib/url.c

@@ -272,6 +272,12 @@ void Curl_freeset(struct SessionHandle * data)
   enum dupstring i;
   for(i=(enum dupstring)0; i < STRING_LAST; i++)
     Curl_safefree(data->set.str[i]);
+
+  if(data->change.referer_alloc) {
+    Curl_safefree(data->change.referer);
+    data->change.referer_alloc = FALSE;
+  }
+  data->change.referer = NULL;
 }
 
 static CURLcode setstropt(char **charp, char * s)

tests/data/test598

@@ -0,0 +1,78 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+HTTP GET
+CURLOPT_REFERER
+curl_easy_reset
+</keywords>
+</info>
+#
+# Server-side
+<reply>
+<data mode="text">
+HTTP/1.1 200 OK
+Date: Thu, 09 Nov 2010 14:49:00 GMT
+Content-Length: 6
+Connection: close
+Content-Type: text/html
+
+-foo-
+</data>
+
+# since the request runs twice
+<datacheck>
+HTTP/1.1 200 OK
+Date: Thu, 09 Nov 2010 14:49:00 GMT
+Content-Length: 6
+Connection: close
+Content-Type: text/html
+
+-foo-
+HTTP/1.1 200 OK
+Date: Thu, 09 Nov 2010 14:49:00 GMT
+Content-Length: 6
+Connection: close
+Content-Type: text/html
+
+-foo-
+</datacheck>
+
+</reply>
+
+# Client-side
+<client>
+<server>
+http
+</server>
+# tool is what to use instead of 'curl'
+<tool>
+lib598
+</tool>
+
+ <name>
+curl_easy_reset with referer and other strings set
+ </name>
+ <command>
+http://%HOSTIP:%HTTPPORT/598
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol>
+GET /598 HTTP/1.1
+User-Agent: the-moo agent next generation
+Host: %HOSTIP:%HTTPPORT
+Accept: */*
+Referer: http://example.com/the-moo
+Cookie: name=moo
+
+GET /598 HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+Accept: */*
+
+</protocol>
+</verify>
+</testcase>

tests/libtest/Makefile.inc

@@ -19,7 +19,7 @@ noinst_PROGRAMS = chkhostname \
   lib543 lib544 lib545 lib547 lib548 lib549 lib552 lib553 lib554 lib555	\
   lib556 lib539 lib557 lib560 lib562 lib564 lib565 lib566 lib567 lib568	\
   lib569 lib570 lib571 lib572 lib573 lib582 lib583 lib585 lib586 lib587 \
-  lib590 lib591 lib597
+  lib590 lib591 lib597 lib598
 
 chkhostname_SOURCES = chkhostname.c $(top_srcdir)/lib/curl_gethostname.c
 chkhostname_LDADD = @CURL_NETWORK_LIBS@
@@ -181,3 +181,5 @@ lib590_SOURCES = lib590.c $(SUPPORTFILES)
 lib591_SOURCES = lib591.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
 
 lib597_SOURCES = lib597.c $(SUPPORTFILES) $(TESTUTIL) $(WARNLESS)
+
+lib598_SOURCES = lib598.c $(SUPPORTFILES)

tests/libtest/lib598.c

@@ -0,0 +1,66 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * 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 "memdebug.h"
+
+int test(char *URL)
+{
+  CURLcode res;
+  CURL *curl;
+
+  if (curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK) {
+    fprintf(stderr, "curl_global_init() failed\n");
+    return TEST_ERR_MAJOR_BAD;
+  }
+
+  if ((curl = curl_easy_init()) == NULL) {
+    fprintf(stderr, "curl_easy_init() failed\n");
+    curl_global_cleanup();
+    return TEST_ERR_MAJOR_BAD;
+  }
+
+  test_setopt(curl, CURLOPT_URL, URL);
+  test_setopt(curl, CURLOPT_HEADER, 1L);
+  test_setopt(curl, CURLOPT_REFERER, "http://example.com/the-moo");
+  test_setopt(curl, CURLOPT_USERAGENT, "the-moo agent next generation");
+  test_setopt(curl, CURLOPT_COOKIE, "name=moo");
+  test_setopt(curl, CURLOPT_VERBOSE, 1L);
+
+  res = curl_easy_perform(curl);
+
+  curl_easy_reset(curl);
+
+  test_setopt(curl, CURLOPT_URL, URL);
+  test_setopt(curl, CURLOPT_HEADER, 1L);
+  test_setopt(curl, CURLOPT_VERBOSE, 1L);
+
+  res = curl_easy_perform(curl);
+
+test_cleanup:
+
+  curl_easy_cleanup(curl);
+  curl_global_cleanup();
+
+  return (int)res;
+}
+