diff --git a/poky/bitbake/lib/bb/siggen.py b/poky/bitbake/lib/bb/siggen.py
index ad49d1e..86e0e16 100644
--- a/poky/bitbake/lib/bb/siggen.py
+++ b/poky/bitbake/lib/bb/siggen.py
@@ -358,7 +358,8 @@
         else:
             sigfile = stampbase + "." + task + ".sigbasedata" + "." + self.basehash[tid]
 
-        bb.utils.mkdirhier(os.path.dirname(sigfile))
+        with bb.utils.umask(0o002):
+            bb.utils.mkdirhier(os.path.dirname(sigfile))
 
         data = {}
         data['task'] = task
@@ -746,16 +747,26 @@
             ret.append(item)
     return '[%s]' % (', '.join(ret))
 
-def clean_basepath(a):
-    mc = None
-    if a.startswith("mc:"):
-        _, mc, a = a.split(":", 2)
-    b = a.rsplit("/", 2)[1] + '/' + a.rsplit("/", 2)[2]
-    if a.startswith("virtual:"):
-        b = b + ":" + a.rsplit(":", 2)[0]
-    if mc:
-        b = b + ":mc:" + mc
-    return b
+def clean_basepath(basepath):
+    basepath, dir, recipe_task = basepath.rsplit("/", 2)
+    cleaned = dir + '/' + recipe_task
+
+    if basepath[0] == '/':
+        return cleaned
+
+    if basepath.startswith("mc:"):
+        mc, mc_name, basepath = basepath.split(":", 2)
+        mc_suffix = ':mc:' + mc_name
+    else:
+        mc_suffix = ''
+
+    # mc stuff now removed from basepath. Whatever was next, if present will be the first
+    # suffix. ':/', recipe path start, marks the end of this. Something like
+    # 'virtual:a[:b[:c]]:/path...' (b and c being optional)
+    if basepath[0] != '/':
+        cleaned += ':' + basepath.split(':/', 1)[0]
+
+    return cleaned + mc_suffix
 
 def clean_basepaths(a):
     b = {}