Better validation and testing of key paths

Previously, we allowed key paths to end in backslashes and we allowed key
names to be more than 255 characters, which are both wrong.

This commit uses a regex to perform better validation. It also adds
better tests, and to ensure that the capture of the repeating capture
group works (for more than a single level).

lib/puppet/util/registry_base.rb

@@ -47,8 +47,11 @@ def ascend(hkey, subkey, &block)
   end
 
   def key_split(path)
-    rootkey, subkey = path.split('\\', 2)
+    unless match = /^([^\\]*)((?:\\[^\\]{1,255})*)$/.match(path)
+      raise ArgumentError, "Invalid registry key: #{path}"
+    end
 
+    rootkey, subkey = match.captures
     hkey =
         case rootkey.downcase
         when /hkey_local_machine/, /hklm/

spec/unit/puppet/type/registry_key_spec.rb

@@ -3,8 +3,7 @@
 require 'puppet/util/registry_base'
 
 describe Puppet::Type.type(:registry_key) do
-  let (:path) { 'HKLM\Software\PuppetSpecTest' }
-  let (:key) { Puppet::Type.type(:registry_key).new(:path => path) }
+  let (:key) { Puppet::Type.type(:registry_key).new(:path => 'HKLM\Software') }
 
   [:ensure].each do |property|
     it "should have a #{property} property" do
@@ -21,26 +20,23 @@
       Puppet::Type.type(:registry_key).attrtype(:path).should == :param
     end
 
-    it 'should accept a fully qualified path' do
-      key[:path].should == path
-    end
-
-    Puppet::Util::RegistryBase::HKEYS.each do |hkey|
-      it "should accept #{hkey}\\Subkey" do
-        described_class.new(:path => "#{hkey}\\Subkey")
+    %w[hklm hklm\software hklm\software\vendor].each do |path|
+      it "should accept #{path}" do
+        key[:path] = path
       end
     end
 
-    it 'should reject unknown keys' do
-      expect { key[:path] = 'UNKNOWN\Subkey' }.should raise_error(Puppet::Error)
-    end
-
-    it 'should accept a valid root key' do
-      key[:path] = 'HKLM'
+    %w[unknown unknown\subkey HKEY_PERFORMANCE_DATA].each do |path|
+      it "should reject #{path} as unsupported" do
+        expect { key[:path] = path }.should raise_error(Puppet::Error, /Unsupported/)
+      end
     end
 
-    it 'should reject an unknown root key' do
-      expect { key[:path] = 'UNKNOWN' }.should raise_error(Puppet::Error)
+    %[hklm\\ hklm\foo\\].each do |path|
+      it "should reject #{path} as invalid" do
+        path = "hklm\\" + 'a' * 256
+        expect { key[:path] = path }.should raise_error(Puppet::Error, /Invalid registry key/)
+      end
     end
 
     %w[HKLM HKEY_LOCAL_MACHINE hklm].each do |root|