Fixed command Injection

* lib/resolv.rb (Resolv::Config.parse_resolv_conf): fixed
  potential command injection by use of Kernel#open.
  [ruby-core:84347] [Bug #14205]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61351 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/resolv.rb

@@ -928,7 +928,7 @@ class Resolv
         nameserver = []
         search = nil
         ndots = 1
-        open(filename, 'rb') {|f|
+        File.open(filename, 'rb') {|f|
           f.each {|line|
             line.sub!(/[#;].*/, '')
             keyword, *args = line.split(/\s+/)

test/resolv/test_addr.rb

@@ -27,4 +27,15 @@ class TestResolvAddr < Test::Unit::TestCase
       end
     end
   end
+
+  def test_hosts_by_command
+    Dir.mktmpdir do |dir|
+      Dir.chdir(dir) do
+        hosts = Resolv::Hosts.new("|echo error")
+        assert_raise(Errno::ENOENT) do
+          hosts.each_name("") {}
+        end
+      end
+    end
+  end
 end

test/resolv/test_dns.rb

@@ -179,6 +179,16 @@ class TestResolvDNS < Test::Unit::TestCase
     end
   end
 
+  def test_resolv_conf_by_command
+    Dir.mktmpdir do |dir|
+      Dir.chdir(dir) do
+        assert_raise(Errno::ENOENT) do
+          Resolv::DNS::Config.parse_resolv_conf("|echo foo")
+        end
+      end
+    end
+  end
+
   def test_dots_diffences
     name1 = Resolv::DNS::Name.create("example.org")
     name2 = Resolv::DNS::Name.create("ex.ampl.eo.rg")