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diff --git a/jni/ruby/lib/rubygems/security/policy.rb b/jni/ruby/lib/rubygems/security/policy.rb
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+++ b/jni/ruby/lib/rubygems/security/policy.rb
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+require 'rubygems/user_interaction'
+
+##
+# A Gem::Security::Policy object encapsulates the settings for verifying
+# signed gem files.  This is the base class.  You can either declare an
+# instance of this or use one of the preset security policies in
+# Gem::Security::Policies.
+
+class Gem::Security::Policy
+
+  include Gem::UserInteraction
+
+  attr_reader :name
+
+  attr_accessor :only_signed
+  attr_accessor :only_trusted
+  attr_accessor :verify_chain
+  attr_accessor :verify_data
+  attr_accessor :verify_root
+  attr_accessor :verify_signer
+
+  ##
+  # Create a new Gem::Security::Policy object with the given mode and
+  # options.
+
+  def initialize name, policy = {}, opt = {}
+    require 'openssl'
+
+    @name = name
+
+    @opt = opt
+
+    # Default to security
+    @only_signed   = true
+    @only_trusted  = true
+    @verify_chain  = true
+    @verify_data   = true
+    @verify_root   = true
+    @verify_signer = true
+
+    policy.each_pair do |key, val|
+      case key
+      when :verify_data   then @verify_data   = val
+      when :verify_signer then @verify_signer = val
+      when :verify_chain  then @verify_chain  = val
+      when :verify_root   then @verify_root   = val
+      when :only_trusted  then @only_trusted  = val
+      when :only_signed   then @only_signed   = val
+      end
+    end
+  end
+
+  ##
+  # Verifies each certificate in +chain+ has signed the following certificate
+  # and is valid for the given +time+.
+
+  def check_chain chain, time
+    raise Gem::Security::Exception, 'missing signing chain' unless chain
+    raise Gem::Security::Exception, 'empty signing chain' if chain.empty?
+
+    begin
+      chain.each_cons 2 do |issuer, cert|
+        check_cert cert, issuer, time
+      end
+
+      true
+    rescue Gem::Security::Exception => e
+      raise Gem::Security::Exception, "invalid signing chain: #{e.message}"
+    end
+  end
+
+  ##
+  # Verifies that +data+ matches the +signature+ created by +public_key+ and
+  # the +digest+ algorithm.
+
+  def check_data public_key, digest, signature, data
+    raise Gem::Security::Exception, "invalid signature" unless
+      public_key.verify digest.new, signature, data.digest
+
+    true
+  end
+
+  ##
+  # Ensures that +signer+ is valid for +time+ and was signed by the +issuer+.
+  # If the +issuer+ is +nil+ no verification is performed.
+
+  def check_cert signer, issuer, time
+    raise Gem::Security::Exception, 'missing signing certificate' unless
+      signer
+
+    message = "certificate #{signer.subject}"
+
+    if not_before = signer.not_before and not_before > time then
+      raise Gem::Security::Exception,
+            "#{message} not valid before #{not_before}"
+    end
+
+    if not_after = signer.not_after and not_after < time then
+      raise Gem::Security::Exception, "#{message} not valid after #{not_after}"
+    end
+
+    if issuer and not signer.verify issuer.public_key then
+      raise Gem::Security::Exception,
+            "#{message} was not issued by #{issuer.subject}"
+    end
+
+    true
+  end
+
+  ##
+  # Ensures the public key of +key+ matches the public key in +signer+
+
+  def check_key signer, key
+    unless signer and key then
+      return true unless @only_signed
+
+      raise Gem::Security::Exception, 'missing key or signature'
+    end
+
+    raise Gem::Security::Exception,
+      "certificate #{signer.subject} does not match the signing key" unless
+        signer.public_key.to_pem == key.public_key.to_pem
+
+    true
+  end
+
+  ##
+  # Ensures the root certificate in +chain+ is self-signed and valid for
+  # +time+.
+
+  def check_root chain, time
+    raise Gem::Security::Exception, 'missing signing chain' unless chain
+
+    root = chain.first
+
+    raise Gem::Security::Exception, 'missing root certificate' unless root
+
+    raise Gem::Security::Exception,
+          "root certificate #{root.subject} is not self-signed " +
+          "(issuer #{root.issuer})" if
+      root.issuer.to_s != root.subject.to_s # HACK to_s is for ruby 1.8
+
+    check_cert root, root, time
+  end
+
+  ##
+  # Ensures the root of +chain+ has a trusted certificate in +trust_dir+ and
+  # the digests of the two certificates match according to +digester+
+
+  def check_trust chain, digester, trust_dir
+    raise Gem::Security::Exception, 'missing signing chain' unless chain
+
+    root = chain.first
+
+    raise Gem::Security::Exception, 'missing root certificate' unless root
+
+    path = Gem::Security.trust_dir.cert_path root
+
+    unless File.exist? path then
+      message = "root cert #{root.subject} is not trusted"
+
+      message << " (root of signing cert #{chain.last.subject})" if
+        chain.length > 1
+
+      raise Gem::Security::Exception, message
+    end
+
+    save_cert = OpenSSL::X509::Certificate.new File.read path
+    save_dgst = digester.digest save_cert.public_key.to_s
+
+    pkey_str = root.public_key.to_s
+    cert_dgst = digester.digest pkey_str
+
+    raise Gem::Security::Exception,
+          "trusted root certificate #{root.subject} checksum " +
+          "does not match signing root certificate checksum" unless
+      save_dgst == cert_dgst
+
+    true
+  end
+
+  ##
+  # Extracts the email or subject from +certificate+
+
+  def subject certificate # :nodoc:
+    certificate.extensions.each do |extension|
+      next unless extension.oid == 'subjectAltName'
+
+      return extension.value
+    end
+
+    certificate.subject.to_s
+  end
+
+  def inspect # :nodoc:
+    ("[Policy: %s - data: %p signer: %p chain: %p root: %p " +
+     "signed-only: %p trusted-only: %p]") % [
+      @name, @verify_chain, @verify_data, @verify_root, @verify_signer,
+      @only_signed, @only_trusted,
+    ]
+  end
+
+  ##
+  # For +full_name+, verifies the certificate +chain+ is valid, the +digests+
+  # match the signatures +signatures+ created by the signer depending on the
+  # +policy+ settings.
+  #
+  # If +key+ is given it is used to validate the signing certificate.
+
+  def verify chain, key = nil, digests = {}, signatures = {},
+             full_name = '(unknown)'
+    if signatures.empty? then
+      if @only_signed then
+        raise Gem::Security::Exception,
+          "unsigned gems are not allowed by the #{name} policy"
+      elsif digests.empty? then
+        # lack of signatures is irrelevant if there is nothing to check
+        # against
+      else
+        alert_warning "#{full_name} is not signed"
+        return
+      end
+    end
+
+    opt       = @opt
+    digester  = Gem::Security::DIGEST_ALGORITHM
+    trust_dir = opt[:trust_dir]
+    time      = Time.now
+
+    _, signer_digests = digests.find do |algorithm, file_digests|
+      file_digests.values.first.name == Gem::Security::DIGEST_NAME
+    end
+
+    if @verify_data then
+      raise Gem::Security::Exception, 'no digests provided (probable bug)' if
+        signer_digests.nil? or signer_digests.empty?
+    else
+      signer_digests = {}
+    end
+
+    signer = chain.last
+
+    check_key signer, key if key
+
+    check_cert signer, nil, time if @verify_signer
+
+    check_chain chain, time if @verify_chain
+
+    check_root chain, time if @verify_root
+
+    if @only_trusted then
+      check_trust chain, digester, trust_dir
+    elsif signatures.empty? and digests.empty? then
+      # trust is irrelevant if there's no signatures to verify
+    else
+      alert_warning "#{subject signer} is not trusted for #{full_name}"
+    end
+
+    signatures.each do |file, _|
+      digest = signer_digests[file]
+
+      raise Gem::Security::Exception, "missing digest for #{file}" unless
+        digest
+    end
+
+    signer_digests.each do |file, digest|
+      signature = signatures[file]
+
+      raise Gem::Security::Exception, "missing signature for #{file}" unless
+        signature
+
+      check_data signer.public_key, digester, signature, digest if @verify_data
+    end
+
+    true
+  end
+
+  ##
+  # Extracts the certificate chain from the +spec+ and calls #verify to ensure
+  # the signatures and certificate chain is valid according to the policy..
+
+  def verify_signatures spec, digests, signatures
+    chain = spec.cert_chain.map do |cert_pem|
+      OpenSSL::X509::Certificate.new cert_pem
+    end
+
+    verify chain, nil, digests, signatures, spec.full_name
+
+    true
+  end
+
+  alias to_s name # :nodoc:
+
+end
+