virt-aa-helper: fix parsing security labels by introducing VIR_DOMAIN_DEF_PARSE_SKIP_SECLABEL

When virt-aa-helper parses xml content it can fail on security labels.

It fails by requiring to parse active domain content on seclabels that
are not yet filled in.

Testcase with virt-aa-helper on a minimal xml:
 $ cat << EOF > /tmp/test.xml
<domain type='kvm'>
    <name>test-seclabel</name>
    <uuid>12345678-9abc-def1-2345-6789abcdef00</uuid>
    <memory unit='KiB'>1</memory>
    <os><type arch='x86_64'>hvm</type></os>
    <seclabel type='dynamic' model='apparmor' relabel='yes'/>
    <seclabel type='dynamic' model='dac' relabel='yes'/>
</domain>
EOF
 $ /usr/lib/libvirt/virt-aa-helper -d -r -p 0 \
   -u libvirt-12345678-9abc-def1-2345-6789abcdef00 < /tmp/test.xml

Current Result:
 virt-aa-helper: error: could not parse XML
 virt-aa-helper: error: could not get VM definition
Expected Result is a valid apparmor profile
Signed-off-by: NChristian Ehrhardt <christian.ehrhardt@canonical.com>
Signed-off-by: NGuido Günther <agx@sigxcpu.org>

src/conf/domain_conf.c

@@ -16372,8 +16372,10 @@ virDomainDefParseXML(xmlDocPtr xml,
 
     /* analysis of security label, done early even though we format it
      * late, so devices can refer to this for defaults */
-    if (virSecurityLabelDefsParseXML(def, ctxt, caps, flags) == -1)
-        goto error;
+    if (!(flags & VIR_DOMAIN_DEF_PARSE_SKIP_SECLABEL)) {
+        if (virSecurityLabelDefsParseXML(def, ctxt, caps, flags) == -1)
+            goto error;
+    }
 
     /* Extract domain memory */
     if (virDomainParseMemory("./memory[1]", NULL, ctxt,

src/conf/domain_conf.h

@@ -2684,6 +2684,8 @@ typedef enum {
     VIR_DOMAIN_DEF_PARSE_ABI_UPDATE = 1 << 9,
     /* skip definition validation checks meant to be executed on define time only */
     VIR_DOMAIN_DEF_PARSE_SKIP_VALIDATE = 1 << 10,
+    /* skip parsing of security labels */
+    VIR_DOMAIN_DEF_PARSE_SKIP_SECLABEL        = 1 << 11,
 } virDomainDefParseFlags;
 
 typedef enum {

src/security/virt-aa-helper.c

@@ -705,6 +705,7 @@ get_definition(vahControl * ctl, const char *xmlStr)
 
     ctl->def = virDomainDefParseString(xmlStr,
                                        ctl->caps, ctl->xmlopt, NULL,
+                                       VIR_DOMAIN_DEF_PARSE_SKIP_SECLABEL |
                                        VIR_DOMAIN_DEF_PARSE_SKIP_VALIDATE);
 
     if (ctl->def == NULL) {