Fixes #16909 - properly escape user and pass in proxy auth

rest-client alongside URIs parse method introduces a bug
where by usernames or passwords cannot have symbols in them.
More Information:
 rest-client/rest-client#661
 ManageIQ/manageiq#17318

app/lib/katello/util/http_proxy.rb

@@ -1,12 +1,23 @@
+require 'katello/util/proxy_uri'
+
 module Katello
   module Util
     module HttpProxy
       def proxy_uri
-        URI("#{proxy_scheme}://#{proxy_user_info}@#{proxy_host}:#{proxy_port}").to_s if proxy_host
-      end
+        #Reset the scheme to proxy(s) based on http or https to handle cgi unescaping in rest-client
+        # this relies on katello/util/proxy_uri
+        if proxy_host
+          scheme = 'proxy' if proxy_scheme == 'http'
+          scheme = 'proxys' if proxy_scheme == 'https'
+
+          uri = URI("#{scheme}://#{proxy_host}:#{proxy_port}")
+          if proxy_config && proxy_config[:user]
+            uri.user = CGI.escape(proxy_config[:user])
+            uri.password = CGI.escape(proxy_config[:password])
+          end
 
-      def proxy_user_info
-        "#{proxy_config[:user]}:#{proxy_config[:password]}" if proxy_config && proxy_config[:user]
+          uri.to_s
+        end
       end
 
       def proxy_config

app/lib/katello/util/proxy_uri.rb

@@ -0,0 +1,64 @@
+#
+# The Ruby URI parser doesn't decode the percent encoded characters in the URI, in particular it
+# doesn't decode the password which is frequently used when specifying proxy addresses and
+# authentication. For example, the following code:
+#
+#   require 'uri'
+#   proxy = URI.parse('http://myuser:%24%[email protected]:3128')
+#   puts proxy.password
+#
+# Produces the following output:
+#
+#   %24%3fxxxx
+#
+# But some gems, in particular `rest-client` and `kubeclient`, expect it to decode those characters,
+# as they use the value returned by the `password` method directly, and thus they fail to
+# authenticate against the proxy server when the password contains percent encoded characters.
+#
+# To address this issue this file adds a new `proxy` URI schema that almost identical to the `http`
+# schema, but that decodes the password before returning it. Users can use this schema instead of
+# `http` when they need to use percent encoded characters in the password. For example, the user
+# can type in the UI the following proxy URL:
+#
+#   proxy://myuser:%24%[email protected]:3128
+#
+# And the new schema will automatically translate `%24%3fxxxx` into `$?xxxx`.
+# This fix is derived from: https://github.com/ManageIQ/manageiq/pull/17318
+require 'cgi'
+require 'uri'
+
+module URI
+  class ProxyUri < HTTP
+    def password
+      value = super
+      value = CGI.unescape(value) if value
+      value
+    end
+
+    def user
+      value = super
+      value = CGI.unescape(value) if value
+      value
+    end
+  end
+
+  @@schemes['PROXY'] = ProxyUri
+end
+
+module URI
+  class ProxysUri < HTTP
+    def password
+      value = super
+      value = CGI.unescape(value) if value
+      value
+    end
+
+    def user
+      value = super
+      value = CGI.unescape(value) if value
+      value
+    end
+  end
+
+  @@schemes['PROXYS'] = ProxysUri
+end

test/lib/util/http_proxy_test.rb

@@ -0,0 +1,31 @@
+require 'katello_test_helper'
+
+module Katello
+  module Util
+    class HttpProxyTest < ActiveSupport::TestCase
+      include Katello::Util::HttpProxy
+
+      def test_handles_no_username_test
+        SETTINGS[:katello][:cdn_proxy] = {
+          host: 'http://foobar.com',
+          username: nil,
+          password: nil
+        }
+        assert_equal 'proxy://foobar.com', proxy_uri
+      end
+
+      def test_properly_escapes_username
+        SETTINGS[:katello][:cdn_proxy] = {
+          host: 'http://foobar.com',
+          user: 'red!hat',
+          password: 'red@hat'
+        }
+        assert_equal 'proxy://red%21hat:red%[email protected]', proxy_uri
+
+        uri = URI.parse(proxy_uri)
+        assert_equal 'red!hat', uri.user
+        assert_equal 'red@hat', uri.password
+      end
+    end
+  end
+end