selinux: Fix incorrect object label generation.

This is a fix for the object label generation. It uses a new flag for
virSecuritySELinuxGenNewContext that specifies whether the context is
for an object. If so the context role remains unchanged.
Without this fix it is not possible to start domains with image file or
block device backed storage when selinux is enabled.
Signed-off-by: NViktor Mihajlovski <mihajlov@linux.vnet.ibm.com>

src/security/security_selinux.c

@@ -141,7 +141,9 @@ cleanup:
 
 
 static char *
-virSecuritySELinuxGenNewContext(const char *basecontext, const char *mcs)
+virSecuritySELinuxGenNewContext(const char *basecontext,
+                                const char *mcs,
+                                bool isObjectContext)
 {
     context_t context = NULL;
     char *ret = NULL;
@@ -176,10 +178,11 @@ virSecuritySELinuxGenNewContext(const char *basecontext, const char *mcs)
         goto cleanup;
     }
 
-    if (context_role_set(context,
+    if (!isObjectContext &&
+        context_role_set(context,
                          context_role_get(ourContext)) != 0) {
         virReportSystemError(errno,
-                             _("Unable to set SELinux context user '%s'"),
+                             _("Unable to set SELinux context role '%s'"),
                              context_role_get(ourContext));
         goto cleanup;
     }
@@ -421,7 +424,8 @@ virSecuritySELinuxGenSecurityLabel(virSecurityManagerPtr mgr,
         if (!(def->seclabel.label =
               virSecuritySELinuxGenNewContext(def->seclabel.baselabel ?
                                               def->seclabel.baselabel :
-                                              data->domain_context, mcs)))
+                                              data->domain_context,
+                                              mcs, false)))
             goto cleanup;
         break;
 
@@ -438,7 +442,7 @@ virSecuritySELinuxGenSecurityLabel(virSecurityManagerPtr mgr,
 
     if (!def->seclabel.norelabel) {
         if (!(def->seclabel.imagelabel =
-              virSecuritySELinuxGenNewContext(data->file_context, mcs)))
+              virSecuritySELinuxGenNewContext(data->file_context, mcs, true)))
             goto cleanup;
     }
 
@@ -1639,7 +1643,8 @@ virSecuritySELinuxGenImageLabel(virSecurityManagerPtr mgr,
                 virReportOOMError();
                 goto cleanup;
             }
-            if (!(label = virSecuritySELinuxGenNewContext(data->file_context, mcs)))
+            if (!(label = virSecuritySELinuxGenNewContext(data->file_context,
+                                                          mcs, true)))
                 goto cleanup;
         }
     }