conf: forbid seclabel duplicates for domain devices

Parser checks for per-domain seclabel duplicates, so it would be nice if
it checked for per-device seclabel duplicates the same way

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1165485

src/conf/domain_conf.c

@@ -5421,6 +5421,15 @@ virSecurityDeviceLabelDefParseXML(virSecurityDeviceLabelDefPtr **seclabels_rtn,
                     break;
                 }
             }
+
+            /* check for duplicate seclabels */
+            for (j = 0; j < i; j++) {
+                if (STREQ_NULLABLE(model, seclabels[j]->model)) {
+                    virReportError(VIR_ERR_XML_DETAIL,
+                                   _("seclabel for model %s is already provided"), model);
+                    goto error;
+                }
+            }
             seclabels[i]->model = model;
         }
 

tests/qemuxml2argvdata/qemuxml2argv-seclabel-device-duplicates.xml

+<domain type='qemu' id='1'>
+  <name>QEMUGuest1</name>
+  <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
+  <memory unit='KiB'>219100</memory>
+  <currentMemory unit='KiB'>219100</currentMemory>
+  <vcpu placement='static' cpuset='1-4,8-20,525'>1</vcpu>
+  <os>
+    <type arch='i686' machine='pc'>hvm</type>
+    <boot dev='hd'/>
+  </os>
+  <clock offset='utc'/>
+  <on_poweroff>destroy</on_poweroff>
+  <on_reboot>restart</on_reboot>
+  <on_crash>destroy</on_crash>
+  <devices>
+    <emulator>/usr/bin/qemu</emulator>
+    <disk type='block' device='disk'>
+      <source dev='/dev/HostVG/QEMUGuest1'>
+        <seclabel model='selinux' relabel='no'/>
+        <seclabel model='selinux' relabel='no'/>
+        <seclabel model='selinux' relabel='no'/>
+      </source>
+      <target dev='hda' bus='ide'/>
+      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
+    </disk>
+    <controller type='usb' index='0'/>
+    <controller type='ide' index='0'/>
+    <controller type='pci' index='0' model='pci-root'/>
+    <memballoon model='virtio'/>
+  </devices>
+  <seclabel type='none' relabel='no'/>
+  <seclabel type='dynamic' model='dac' relabel='yes'/>
+</domain>

tests/qemuxml2argvtest.c

@@ -1302,6 +1302,7 @@ mymain(void)
     DO_TEST("seclabel-none", QEMU_CAPS_NAME);
     DO_TEST("seclabel-dac-none", QEMU_CAPS_NAME);
     DO_TEST_PARSE_ERROR("seclabel-multiple", QEMU_CAPS_NAME);
+    DO_TEST_PARSE_ERROR("seclabel-device-duplicates", QEMU_CAPS_NAME);
 
     DO_TEST("pseries-basic",
             QEMU_CAPS_CHARDEV, QEMU_CAPS_DEVICE, QEMU_CAPS_NODEFCONFIG);