virDomainHostdevSubsysSCSIVHostDefParseXML: Don't leak @protocol

==24748== 12 bytes in 2 blocks are definitely lost in loss record 25 of 84
==24748==    at 0x4C2BF80: malloc (vg_replace_malloc.c:296)
==24748==    by 0x1A1E1E78: xmlStrndup (in /usr/lib64/libxml2.so.2.9.4)
==24748==    by 0x18D0495F: virXMLPropString (virxml.c:506)
==24748==    by 0x18D1FB3E: virDomainHostdevSubsysSCSIVHostDefParseXML (domain_conf.c:6280)
==24748==    by 0x18D20350: virDomainHostdevDefParseXMLSubsys (domain_conf.c:6450)
==24748==    by 0x18D34E7D: virDomainHostdevDefParseXML (domain_conf.c:13218)
==24748==    by 0x18D42598: virDomainDefParseXML (domain_conf.c:17745)
==24748==    by 0x18D440A9: virDomainDefParseNode (domain_conf.c:18236)
==24748==    by 0x18D43EFA: virDomainDefParse (domain_conf.c:18180)
==24748==    by 0x18D43FA0: virDomainDefParseFile (domain_conf.c:18206)
==24748==    by 0x44EDA1: testCompareDomXML2XMLFiles (testutils.c:1140)
==24748==    by 0x4365F8: testXML2XMLActive (qemuxml2xmltest.c:59)
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/conf/domain_conf.c

@@ -6275,12 +6275,14 @@ virDomainHostdevSubsysSCSIVHostDefParseXML(xmlNodePtr sourcenode,
                                            virDomainHostdevDefPtr def)
 {
     char *protocol = NULL;
+    char *wwpn = NULL;
     virDomainHostdevSubsysSCSIVHostPtr hostsrc = &def->source.subsys.u.scsi_host;
+    int ret = -1;
 
     if (!(protocol = virXMLPropString(sourcenode, "protocol"))) {
         virReportError(VIR_ERR_XML_ERROR, "%s",
                        _("Missing scsi_host subsystem protocol"));
-        return -1;
+        return ret;
     }
 
     if ((hostsrc->protocol =
@@ -6293,17 +6295,19 @@ virDomainHostdevSubsysSCSIVHostDefParseXML(xmlNodePtr sourcenode,
 
     switch ((virDomainHostdevSubsysSCSIHostProtocolType) hostsrc->protocol) {
     case VIR_DOMAIN_HOSTDEV_SUBSYS_SCSI_HOST_PROTOCOL_TYPE_VHOST:
-        if (!(hostsrc->wwpn = virXMLPropString(sourcenode, "wwpn"))) {
+        if (!(wwpn = virXMLPropString(sourcenode, "wwpn"))) {
             virReportError(VIR_ERR_XML_ERROR, "%s",
                            _("missing vhost-scsi hostdev source wwpn"));
             goto cleanup;
         }
 
-        if (!STRPREFIX(hostsrc->wwpn, "naa.") ||
-            !virValidateWWN(hostsrc->wwpn + 4)) {
+        if (!STRPREFIX(wwpn, "naa.") ||
+            !virValidateWWN(wwpn + 4)) {
             virReportError(VIR_ERR_XML_ERROR, "%s", _("malformed 'wwpn' value"));
             goto cleanup;
         }
+        hostsrc->wwpn = wwpn;
+        wwpn = NULL;
         break;
     case VIR_DOMAIN_HOSTDEV_SUBSYS_SCSI_HOST_PROTOCOL_TYPE_NONE:
     case VIR_DOMAIN_HOSTDEV_SUBSYS_SCSI_HOST_PROTOCOL_TYPE_LAST:
@@ -6314,12 +6318,11 @@ virDomainHostdevSubsysSCSIVHostDefParseXML(xmlNodePtr sourcenode,
         break;
     }
 
-    return 0;
-
+    ret = 0;
  cleanup:
-    VIR_FREE(hostsrc->wwpn);
+    VIR_FREE(wwpn);
     VIR_FREE(protocol);
-    return -1;
+    return ret;
 }