ruby/SOURCES/ruby-2.5.4-fix-malicious-gem-to-lead-to-arbitrary-code-execution.patch

diff --git a/lib/rubygems/installer.rb b/lib/rubygems/installer.rb
index ee5fedeb64..a3f9571cf3 100644
--- a/lib/rubygems/installer.rb
+++ b/lib/rubygems/installer.rb
@@ -707,9 +707,26 @@ def verify_gem_home(unpack = false) # :nodoc:
       unpack or File.writable?(gem_home)
   end
 
-  def verify_spec_name
-    return if spec.name =~ Gem::Specification::VALID_NAME_PATTERN
-    raise Gem::InstallError, "#{spec} has an invalid name"
+  def verify_spec
+    unless spec.name =~ Gem::Specification::VALID_NAME_PATTERN
+      raise Gem::InstallError, "#{spec} has an invalid name"
+    end
+
+    if spec.raw_require_paths.any?{|path| path =~ /\R/ }
+      raise Gem::InstallError, "#{spec} has an invalid require_paths"
+    end
+
+    if spec.extensions.any?{|ext| ext =~ /\R/ }
+      raise Gem::InstallError, "#{spec} has an invalid extensions"
+    end
+
+    if spec.specification_version.to_s =~ /\R/
+      raise Gem::InstallError, "#{spec} has an invalid specification_version"
+    end
+
+    if spec.dependencies.any? {|dep| dep.type =~ /\R/ || dep.name =~ /\R/ }
+      raise Gem::InstallError, "#{spec} has an invalid dependencies"
+    end
   end
 
   ##
@@ -836,9 +853,11 @@ def dir
   def pre_install_checks
     verify_gem_home options[:unpack]
 
-    ensure_loadable_spec
+    # The name and require_paths must be verified first, since it could contain
+    # ruby code that would be eval'ed in #ensure_loadable_spec
+    verify_spec
 
-    verify_spec_name
+    ensure_loadable_spec
 
     if options[:install_as_default]
       Gem.ensure_default_gem_subdirectories gem_home
diff --git a/test/rubygems/test_gem_installer.rb b/test/rubygems/test_gem_installer.rb
index 93b0482407..7f414d495d 100644
--- a/test/rubygems/test_gem_installer.rb
+++ b/test/rubygems/test_gem_installer.rb
@@ -1474,6 +1474,112 @@ def spec.validate; end
     end
   end
 
+  def test_pre_install_checks_malicious_name_before_eval
+    spec = util_spec "malicious\n::Object.const_set(:FROM_EVAL, true)#", '1'
+    def spec.full_name # so the spec is buildable
+      "malicious-1"
+    end
+    def spec.validate(*args); end
+
+    util_build_gem spec
+
+    gem = File.join(@gemhome, 'cache', spec.file_name)
+
+    use_ui @ui do
+      @installer = Gem::Installer.at gem
+      e = assert_raises Gem::InstallError do
+        @installer.pre_install_checks
+      end
+      assert_equal "#<Gem::Specification name=malicious\n::Object.const_set(:FROM_EVAL, true)# version=1> has an invalid name", e.message
+    end
+    refute defined?(::Object::FROM_EVAL)
+  end
+
+  def test_pre_install_checks_malicious_require_paths_before_eval
+    spec = util_spec "malicious", '1'
+    def spec.full_name # so the spec is buildable
+      "malicious-1"
+    end
+    def spec.validate(*args); end
+    spec.require_paths = ["malicious\n``"]
+
+    util_build_gem spec
+
+    gem = File.join(@gemhome, 'cache', spec.file_name)
+
+    use_ui @ui do
+      @installer = Gem::Installer.at gem
+      e = assert_raises Gem::InstallError do
+        @installer.pre_install_checks
+      end
+      assert_equal "#<Gem::Specification name=malicious version=1> has an invalid require_paths", e.message
+    end
+  end
+
+  def test_pre_install_checks_malicious_extensions_before_eval
+    spec = util_spec "malicious", '1'
+    def spec.full_name # so the spec is buildable
+      "malicious-1"
+    end
+    def spec.validate(*args); end
+    spec.extensions = ["malicious\n``"]
+
+    util_build_gem spec
+
+    gem = File.join(@gemhome, 'cache', spec.file_name)
+
+    use_ui @ui do
+      @installer = Gem::Installer.at gem
+      e = assert_raises Gem::InstallError do
+        @installer.pre_install_checks
+      end
+      assert_equal "#<Gem::Specification name=malicious version=1> has an invalid extensions", e.message
+    end
+  end
+
+  def test_pre_install_checks_malicious_specification_version_before_eval
+    spec = util_spec "malicious", '1'
+    def spec.full_name # so the spec is buildable
+      "malicious-1"
+    end
+    def spec.validate(*args); end
+    spec.specification_version = "malicious\n``"
+
+    util_build_gem spec
+
+    gem = File.join(@gemhome, 'cache', spec.file_name)
+
+    use_ui @ui do
+      @installer = Gem::Installer.at gem
+      e = assert_raises Gem::InstallError do
+        @installer.pre_install_checks
+      end
+      assert_equal "#<Gem::Specification name=malicious version=1> has an invalid specification_version", e.message
+    end
+  end
+
+  def test_pre_install_checks_malicious_dependencies_before_eval
+    spec = util_spec "malicious", '1'
+    def spec.full_name # so the spec is buildable
+      "malicious-1"
+    end
+    def spec.validate(*args); end
+    spec.add_dependency "b\nfoo", '> 5'
+
+    util_build_gem spec
+
+    gem = File.join(@gemhome, 'cache', spec.file_name)
+
+    use_ui @ui do
+      @installer = Gem::Installer.at gem
+      @installer.ignore_dependencies = true
+      e = assert_raises Gem::InstallError do
+        @installer.pre_install_checks
+      end
+      assert_equal "#<Gem::Specification name=malicious version=1> has an invalid dependencies", e.message
+    end
+  end
+
   def test_shebang
     util_make_exec @spec, "#!/usr/bin/ruby"
 
-- 
2.21.0