diff --git lib/rubygems.rb lib/rubygems.rb
index 6a30e315de..dded57bb6a 100644
--- lib/rubygems.rb
+++ lib/rubygems.rb
@@ -9,7 +9,7 @@ require 'rbconfig'
 require 'thread'
 
 module Gem
-  VERSION = '2.4.5.4'
+  VERSION = '2.4.5.5'
 end
 
 # Must be first since it unloads the prelude from 1.9.2
diff --git lib/rubygems/package.rb lib/rubygems/package.rb
index 4d2a2edc80..bd33f4cc13 100644
--- lib/rubygems/package.rb
+++ lib/rubygems/package.rb
@@ -408,7 +408,7 @@ EOM
     destination = File.expand_path destination
 
     raise Gem::Package::PathError.new(destination, destination_dir) unless
-      destination.start_with? destination_dir
+      destination.start_with? destination_dir + '/'
 
     destination.untaint
     destination
@@ -587,6 +587,10 @@ EOM
       raise Gem::Package::FormatError.new \
               'package content (data.tar.gz) is missing', @gem
     end
+
+    if duplicates = @files.group_by {|f| f }.select {|k,v| v.size > 1 }.map(&:first) and duplicates.any?
+      raise Gem::Security::Exception, "duplicate files in the package: (#{duplicates.map(&:inspect).join(', ')})"
+    end
   end
 
   ##
diff --git lib/rubygems/package/tar_header.rb lib/rubygems/package/tar_header.rb
index f9ab13aca7..9b457ec2eb 100644
--- lib/rubygems/package/tar_header.rb
+++ lib/rubygems/package/tar_header.rb
@@ -103,25 +103,30 @@ class Gem::Package::TarHeader
     fields = header.unpack UNPACK_FORMAT
 
     new :name     => fields.shift,
-        :mode     => fields.shift.oct,
-        :uid      => fields.shift.oct,
-        :gid      => fields.shift.oct,
-        :size     => fields.shift.oct,
-        :mtime    => fields.shift.oct,
-        :checksum => fields.shift.oct,
+        :mode     => strict_oct(fields.shift),
+        :uid      => strict_oct(fields.shift),
+        :gid      => strict_oct(fields.shift),
+        :size     => strict_oct(fields.shift),
+        :mtime    => strict_oct(fields.shift),
+        :checksum => strict_oct(fields.shift),
         :typeflag => fields.shift,
         :linkname => fields.shift,
         :magic    => fields.shift,
-        :version  => fields.shift.oct,
+        :version  => strict_oct(fields.shift),
         :uname    => fields.shift,
         :gname    => fields.shift,
-        :devmajor => fields.shift.oct,
-        :devminor => fields.shift.oct,
+        :devmajor => strict_oct(fields.shift),
+        :devminor => strict_oct(fields.shift),
         :prefix   => fields.shift,
 
         :empty => empty
   end
 
+  def self.strict_oct(str)
+    return str.oct if str =~ /\A[0-7]*\z/
+    raise ArgumentError, "#{str.inspect} is not an octal string"
+  end
+
   ##
   # Creates a new TarHeader using +vals+
 
diff --git lib/rubygems/package/tar_writer.rb lib/rubygems/package/tar_writer.rb
index dfd635724b..59bb476664 100644
--- lib/rubygems/package/tar_writer.rb
+++ lib/rubygems/package/tar_writer.rb
@@ -195,6 +195,8 @@ class Gem::Package::TarWriter
       digest_name == signer.digest_name
     end
 
+    raise "no #{signer.digest_name} in #{digests.values.compact}" unless signature_digest
+
     if signer.key then
       signature = signer.sign signature_digest.digest
 
diff --git lib/rubygems/server.rb lib/rubygems/server.rb
index 7655be22ce..728e4f3bf1 100644
--- lib/rubygems/server.rb
+++ lib/rubygems/server.rb
@@ -625,6 +625,18 @@ div.method-source-code pre { color: #ffdead; overflow: hidden; }
       executables = nil if executables.empty?
       executables.last["is_last"] = true if executables
 
+      # Pre-process spec homepage for safety reasons
+      begin
+        homepage_uri = URI.parse(spec.homepage)
+        if [URI::HTTP, URI::HTTPS].member? homepage_uri.class
+          homepage_uri = spec.homepage
+        else
+          homepage_uri = "."
+        end
+      rescue URI::InvalidURIError
+        homepage_uri = "."
+      end
+
       specs << {
         "authors"             => spec.authors.sort.join(", "),
         "date"                => spec.date.to_s,
@@ -634,7 +646,7 @@ div.method-source-code pre { color: #ffdead; overflow: hidden; }
         "only_one_executable" => (executables && executables.size == 1),
         "full_name"           => spec.full_name,
         "has_deps"            => !deps.empty?,
-        "homepage"            => spec.homepage,
+        "homepage"            => homepage_uri,
         "name"                => spec.name,
         "rdoc_installed"      => Gem::RDoc.new(spec).rdoc_installed?,
         "ri_installed"        => Gem::RDoc.new(spec).ri_installed?,
diff --git lib/rubygems/specification.rb lib/rubygems/specification.rb
index 6d46621823..da75d1cf04 100644
--- lib/rubygems/specification.rb
+++ lib/rubygems/specification.rb
@@ -13,6 +13,7 @@ require 'rubygems/deprecate'
 require 'rubygems/basic_specification'
 require 'rubygems/stub_specification'
 require 'rubygems/util/stringio'
+require 'uri'
 
 ##
 # The Specification class contains the information for a Gem.  Typically
@@ -2609,10 +2610,16 @@ http://opensource.org/licenses/alphabetical
       raise Gem::InvalidSpecificationException, "#{lazy} is not a summary"
     end
 
-    if homepage and not homepage.empty? and
-       homepage !~ /\A[a-z][a-z\d+.-]*:/i then
-      raise Gem::InvalidSpecificationException,
-            "\"#{homepage}\" is not a URI"
+    # Make sure a homepage is valid HTTP/HTTPS URI
+    if homepage and not homepage.empty?
+      begin
+        homepage_uri = URI.parse(homepage)
+        unless [URI::HTTP, URI::HTTPS].member? homepage_uri.class
+          raise Gem::InvalidSpecificationException, "\"#{homepage}\" is not a valid HTTP URI"
+        end
+      rescue URI::InvalidURIError
+        raise Gem::InvalidSpecificationException, "\"#{homepage}\" is not a valid HTTP URI"
+      end
     end
 
     # Warnings
diff --git test/rubygems/test_gem_package.rb test/rubygems/test_gem_package.rb
index 128dcdb1c4..233ca362f5 100644
--- test/rubygems/test_gem_package.rb
+++ test/rubygems/test_gem_package.rb
@@ -507,6 +507,21 @@ class TestGemPackage < Gem::Package::TarTestCase
                  "#{@destination} is not allowed", e.message)
   end
 
+  def test_install_location_suffix
+    package = Gem::Package.new @gem
+
+    filename = "../#{File.basename(@destination)}suffix.rb"
+
+    e = assert_raises Gem::Package::PathError do
+      package.install_location filename, @destination
+    end
+
+    parent = File.expand_path File.join @destination, filename
+
+    assert_equal("installing into parent path #{parent} of " +
+                 "#{@destination} is not allowed", e.message)
+  end
+
   def test_load_spec
     entry = StringIO.new Gem.gzip @spec.to_yaml
     def entry.full_name() 'metadata.gz' end
@@ -664,6 +679,32 @@ class TestGemPackage < Gem::Package::TarTestCase
     assert_match %r%nonexistent.gem$%,           e.message
   end
 
+  def test_verify_duplicate_file
+    FileUtils.mkdir_p 'lib'
+    FileUtils.touch 'lib/code.rb'
+
+    build = Gem::Package.new @gem
+    build.spec = @spec
+    build.setup_signer
+    open @gem, 'wb' do |gem_io|
+      Gem::Package::TarWriter.new gem_io do |gem|
+        build.add_metadata gem
+        build.add_contents gem
+
+        gem.add_file_simple 'a.sig', 0444, 0
+        gem.add_file_simple 'a.sig', 0444, 0
+      end
+    end
+
+    package = Gem::Package.new @gem
+
+    e = assert_raises Gem::Security::Exception do
+      package.verify
+    end
+
+    assert_equal 'duplicate files in the package: ("a.sig")', e.message
+  end
+
   def test_verify_security_policy
     skip 'openssl is missing' unless defined?(OpenSSL::SSL)
 
@@ -721,7 +762,13 @@ class TestGemPackage < Gem::Package::TarTestCase
 
         # write bogus data.tar.gz to foil signature
         bogus_data = Gem.gzip 'hello'
-        gem.add_file_simple 'data.tar.gz', 0444, bogus_data.length do |io|
+        fake_signer = Class.new do
+          def digest_name; 'SHA512'; end
+          def digest_algorithm; Digest(:SHA512); end
+          def key; 'key'; end
+          def sign(*); 'fake_sig'; end
+        end
+        gem.add_file_signed 'data2.tar.gz', 0444, fake_signer.new do |io|
           io.write bogus_data
         end
 
diff --git test/rubygems/test_gem_package_tar_header.rb test/rubygems/test_gem_package_tar_header.rb
index 9977e282a1..b9cc933ecc 100644
--- test/rubygems/test_gem_package_tar_header.rb
+++ test/rubygems/test_gem_package_tar_header.rb
@@ -142,5 +142,26 @@ group\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000
     assert_equal '012467', @tar_header.checksum
   end
 
+  def test_from_bad_octal
+    test_cases = [
+      "00000006,44\000", # bogus character
+      "00000006789\000", # non-octal digit
+      "+0000001234\000", # positive sign
+      "-0000001000\000", # negative sign
+      "0x000123abc\000", # radix prefix
+    ]
+
+    test_cases.each do |val|
+      header_s = @tar_header.to_s
+      # overwrite the size field
+      header_s[124, 12] = val
+      io = TempIO.new header_s
+      assert_raises ArgumentError do
+        new_header = Gem::Package::TarHeader.from io
+      end
+      io.close! if io.respond_to? :close!
+    end
+  end
+
 end
 
diff --git test/rubygems/test_gem_server.rb test/rubygems/test_gem_server.rb
index 964048615c..ed11380f29 100644
--- test/rubygems/test_gem_server.rb
+++ test/rubygems/test_gem_server.rb
@@ -331,6 +331,171 @@ class TestGemServer < Gem::TestCase
     assert_match 'z 9', @res.body
   end
 
+
+  def test_xss_homepage_fix_289313
+    data = StringIO.new "GET / HTTP/1.0\r\n\r\n"
+    dir = "#{@gemhome}2"
+
+    spec = util_spec 'xsshomepagegem', 1
+    spec.homepage = "javascript:confirm(document.domain)"
+
+    specs_dir = File.join dir, 'specifications'
+    FileUtils.mkdir_p specs_dir
+
+    open File.join(specs_dir, spec.spec_name), 'w' do |io|
+      io.write spec.to_ruby
+    end
+
+    server = Gem::Server.new dir, process_based_port, false
+
+    @req.parse data
+
+    server.root @req, @res
+
+    assert_equal 200, @res.status
+    assert_match 'xsshomepagegem 1', @res.body
+
+    # This verifies that the homepage for this spec is not displayed and is set to ".", because it's not a 
+    # valid HTTP/HTTPS URL and could be unsafe in an HTML context.  We would prefer to throw an exception here,
+    # but spec.homepage is currently free form and not currently required to be a URL, this behavior may be 
+    # validated in future versions of Gem::Specification.
+    #
+    # There are two variant we're checking here, one where rdoc is not present, and one where rdoc is present in the same regex:
+    #
+    # Variant #1 - rdoc not installed
+    #
+    #   <b>xsshomepagegem 1</b>
+    #
+    #
+    #  <span title="rdoc not installed">[rdoc]</span>
+    #
+    #
+    #
+    #  <a href="." title=".">[www]</a>
+    #
+    # Variant #2 - rdoc installed
+    #
+    #   <b>xsshomepagegem 1</b>
+    #
+    #
+    #  <a href="\/doc_root\/xsshomepagegem-1\/">\[rdoc\]<\/a>
+    #
+    #
+    #
+    #  <a href="." title=".">[www]</a>
+    regex_match = /xsshomepagegem 1<\/b>[\n\s]+(<span title="rdoc not installed">\[rdoc\]<\/span>|<a href="\/doc_root\/xsshomepagegem-1\/">\[rdoc\]<\/a>)[\n\s]+<a href="\." title="\.">\[www\]<\/a>/
+    assert_match regex_match, @res.body
+  end
+
+  def test_invalid_homepage
+    data = StringIO.new "GET / HTTP/1.0\r\n\r\n"
+    dir = "#{@gemhome}2"
+
+    spec = util_spec 'invalidhomepagegem', 1
+    spec.homepage = "notavalidhomepageurl"
+
+    specs_dir = File.join dir, 'specifications'
+    FileUtils.mkdir_p specs_dir
+
+    open File.join(specs_dir, spec.spec_name), 'w' do |io|
+      io.write spec.to_ruby
+    end
+
+    server = Gem::Server.new dir, process_based_port, false
+
+    @req.parse data
+
+    server.root @req, @res
+
+    assert_equal 200, @res.status
+    assert_match 'invalidhomepagegem 1', @res.body
+
+    # This verifies that the homepage for this spec is not displayed and is set to ".", because it's not a 
+    # valid HTTP/HTTPS URL and could be unsafe in an HTML context.  We would prefer to throw an exception here,
+    # but spec.homepage is currently free form and not currently required to be a URL, this behavior may be 
+    # validated in future versions of Gem::Specification.
+    #
+    # There are two variant we're checking here, one where rdoc is not present, and one where rdoc is present in the same regex:
+    #
+    # Variant #1 - rdoc not installed
+    #
+    #   <b>invalidhomepagegem 1</b>
+    #
+    #
+    #  <span title="rdoc not installed">[rdoc]</span>
+    #
+    #
+    #
+    #  <a href="." title=".">[www]</a>
+    #
+    # Variant #2 - rdoc installed
+    #
+    #   <b>invalidhomepagegem 1</b>
+    #
+    #
+    #  <a href="\/doc_root\/invalidhomepagegem-1\/">\[rdoc\]<\/a>
+    #
+    #
+    #
+    #  <a href="." title=".">[www]</a>
+    regex_match = /invalidhomepagegem 1<\/b>[\n\s]+(<span title="rdoc not installed">\[rdoc\]<\/span>|<a href="\/doc_root\/invalidhomepagegem-1\/">\[rdoc\]<\/a>)[\n\s]+<a href="\." title="\.">\[www\]<\/a>/
+    assert_match regex_match, @res.body
+  end
+
+  def test_valid_homepage_http
+    data = StringIO.new "GET / HTTP/1.0\r\n\r\n"
+    dir = "#{@gemhome}2"
+
+    spec = util_spec 'validhomepagegemhttp', 1
+    spec.homepage = "http://rubygems.org"
+
+    specs_dir = File.join dir, 'specifications'
+    FileUtils.mkdir_p specs_dir
+
+    open File.join(specs_dir, spec.spec_name), 'w' do |io|
+      io.write spec.to_ruby
+    end
+
+    server = Gem::Server.new dir, process_based_port, false
+
+    @req.parse data
+
+    server.root @req, @res
+
+    assert_equal 200, @res.status
+    assert_match 'validhomepagegemhttp 1', @res.body
+
+    regex_match = /validhomepagegemhttp 1<\/b>[\n\s]+(<span title="rdoc not installed">\[rdoc\]<\/span>|<a href="\/doc_root\/validhomepagegemhttp-1\/">\[rdoc\]<\/a>)[\n\s]+<a href="http:\/\/rubygems\.org" title="http:\/\/rubygems\.org">\[www\]<\/a>/
+    assert_match regex_match, @res.body
+  end
+
+  def test_valid_homepage_https
+    data = StringIO.new "GET / HTTP/1.0\r\n\r\n"
+    dir = "#{@gemhome}2"
+
+    spec = util_spec 'validhomepagegemhttps', 1
+    spec.homepage = "https://rubygems.org"
+
+    specs_dir = File.join dir, 'specifications'
+    FileUtils.mkdir_p specs_dir
+
+    open File.join(specs_dir, spec.spec_name), 'w' do |io|
+      io.write spec.to_ruby
+    end
+
+    server = Gem::Server.new dir, process_based_port, false
+
+    @req.parse data
+
+    server.root @req, @res
+
+    assert_equal 200, @res.status
+    assert_match 'validhomepagegemhttps 1', @res.body
+
+    regex_match = /validhomepagegemhttps 1<\/b>[\n\s]+(<span title="rdoc not installed">\[rdoc\]<\/span>|<a href="\/doc_root\/validhomepagegemhttps-1\/">\[rdoc\]<\/a>)[\n\s]+<a href="https:\/\/rubygems\.org" title="https:\/\/rubygems\.org">\[www\]<\/a>/
+    assert_match regex_match, @res.body
+  end
+
   def test_specs
     data = StringIO.new "GET /specs.#{Gem.marshal_version} HTTP/1.0\r\n\r\n"
     @req.parse data
diff --git test/rubygems/test_gem_specification.rb test/rubygems/test_gem_specification.rb
index 4f7076a03a..51859419ea 100644
--- test/rubygems/test_gem_specification.rb
+++ test/rubygems/test_gem_specification.rb
@@ -2584,7 +2584,22 @@ duplicate dependency on b (>= 1.2.3), (~> 1.2) use:
         @a1.validate
       end
 
-      assert_equal '"over at my cool site" is not a URI', e.message
+      assert_equal '"over at my cool site" is not a valid HTTP URI', e.message
+
+      @a1.homepage = 'ftp://rubygems.org'
+
+      e = assert_raises Gem::InvalidSpecificationException do
+        @a1.validate
+      end
+
+      assert_equal '"ftp://rubygems.org" is not a valid HTTP URI', e.message
+
+      @a1.homepage = 'http://rubygems.org'
+      assert_equal true, @a1.validate
+
+      @a1.homepage = 'https://rubygems.org'
+      assert_equal true, @a1.validate
+
     end
   end