CVE-2018-1000075

@@ -62,7 +62,7 @@ def show_owners name
     end
 
     with_response response do |resp|
-      owners = YAML.load resp.body
+      owners = Gem::SafeYAML.load resp.body
 
       say "Owners for gem: #{name}"
       owners.each do |owner|

@@ -378,7 +378,7 @@ def extract_tar_gz io, destination_dir, pattern = "*" # :nodoc:
             File.dirname destination
           end
 
-        FileUtils.mkdir_p mkdir, mkdir_options
+        mkdir_p_safe mkdir, mkdir_options, destination_dir, entry.full_name
 
         open destination, 'wb' do |out|
           out.write entry.read
@@ -416,20 +416,35 @@ def install_location filename, destination_dir # :nodoc:
     raise Gem::Package::PathError.new(filename, destination_dir) if
       filename.start_with? '/'
 
-    destination_dir = File.realpath destination_dir if
-      File.respond_to? :realpath
+    destination_dir = realpath destination_dir
     destination_dir = File.expand_path destination_dir
 
     destination = File.join destination_dir, filename
     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
   end
 
+  def mkdir_p_safe mkdir, mkdir_options, destination_dir, file_name
+    destination_dir = realpath File.expand_path(destination_dir)
+    parts = mkdir.split(File::SEPARATOR)
+    parts.reduce do |path, basename|
+      path = realpath path  unless path == ""
+      path = File.expand_path(path + File::SEPARATOR + basename)
+      lstat = File.lstat path rescue nil
+      if !lstat || !lstat.directory?
+        unless path.start_with? destination_dir and (FileUtils.mkdir path, mkdir_options rescue false)
+          raise Gem::Package::PathError.new(file_name, destination_dir)
+        end
+      end
+      path
+    end
+  end
+
   ##
   # Loads a Gem::Specification from the TarEntry +entry+
 
@@ -603,6 +618,10 @@ def verify_files gem
       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
 
   ##
@@ -616,6 +635,16 @@ def verify_gz entry # :nodoc:
     raise Gem::Package::FormatError.new(e.message, entry.full_name)
   end
 
+  if File.respond_to? :realpath
+    def realpath file
+      File.realpath file
+    end
+  else
+    def realpath file
+      file
+    end
+  end
+
 end
 
 require 'rubygems/package/digest_io'

@@ -104,25 +104,30 @@ def self.from(stream)
     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+
 

@@ -196,6 +196,8 @@ def add_file_signed name, mode, signer
       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
 

@@ -10,7 +10,7 @@
 require 'thread'
 
 module Gem
-  VERSION = "2.6.14"
+  VERSION = "2.6.14.1"
 end
 
 # Must be first since it unloads the prelude from 1.9.2

@@ -631,6 +631,18 @@ def root(req, res)
       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,
@@ -640,7 +652,7 @@ def root(req, res)
         "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?,

@@ -15,6 +15,7 @@
 require 'rubygems/stub_specification'
 require 'rubygems/util/list'
 require 'stringio'
+require 'uri'
 
 ##
 # The Specification class contains the information for a Gem.  Typically
@@ -2810,10 +2811,16 @@ def validate packaging = true
       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

@@ -1,5 +1,24 @@
 # coding: UTF-8
 
+=== 2.7.6 / 2018-02-16
+
+Security fixes:
+
+* Prevent path traversal when writing to a symlinked basedir outside of the root.
+  Discovered by nmalkin, fixed by Jonathan Claudius and Samuel Giddins.
+* Fix possible Unsafe Object Deserialization Vulnerability in gem owner.
+  Fixed by Jonathan Claudius.
+* Strictly interpret octal fields in tar headers.
+  Discoved by plover, fixed by Samuel Giddins.
+* Raise a security error when there are duplicate files in a package.
+  Discovered by plover, fixed by Samuel Giddins.
+* Enforce URL validation on spec homepage attribute.
+  Discovered by Yasin Soliman, fixed by Jonathan Claudius.
+* Mitigate XSS vulnerability in homepage attribute when displayed via `gem server`.
+  Discovered by Yasin Soliman, fixed by Jonathan Claudius.
+* Prevent Path Traversal issue during gem installation.
+  Discovered by nmalkin.
+
 === 2.7.4
 
 Bug fixes:

@@ -10,7 +10,7 @@
 require 'thread'
 
 module Gem
-  VERSION = "2.7.5"
+  VERSION = "2.7.6"
 end
 
 # Must be first since it unloads the prelude from 1.9.2

@@ -104,25 +104,30 @@ def self.from(stream)
     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+
 

@@ -143,5 +143,25 @@ def test_update_checksum
     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
+    end
+  end
+
 end