Add support to build and sign certificates with multiple key algorithms

Co-Authored-By: Frederik Dudzik <frederik.dudzik@shopify.com>

Manifest.txt

@@ -541,6 +541,7 @@ test/rubygems/plugin/exception/rubygems_plugin.rb
 test/rubygems/plugin/load/rubygems_plugin.rb
 test/rubygems/plugin/standarderror/rubygems_plugin.rb
 test/rubygems/private3072_key.pem
+test/rubygems/private_ec_key.pem
 test/rubygems/private_key.pem
 test/rubygems/public3072_cert.pem
 test/rubygems/public_cert.pem

lib/rubygems/commands/cert_command.rb

@@ -43,6 +43,11 @@ def initialize
       options[:key] = open_private_key(key_file)
     end
 
+    add_option('-A', '--key-algorithm ALGORITHM',
+               'Select which key algorithm to use for --build') do |algorithm, options|
+      options[:key_algorithm] = algorithm
+    end
+
     add_option('-s', '--sign CERT',
                'Signs CERT with the key from -K',
                'and the certificate from -C') do |cert_file, options|
@@ -89,14 +94,14 @@ def open_cert(certificate_file)
   def open_private_key(key_file)
     check_openssl
     passphrase = ENV['GEM_PRIVATE_KEY_PASSPHRASE']
-    key = OpenSSL::PKey::RSA.new File.read(key_file), passphrase
+    key = OpenSSL::PKey.read File.read(key_file), passphrase
     raise OptionParser::InvalidArgument,
       "#{key_file}: private key not found" unless key.private?
     key
   rescue Errno::ENOENT
     raise OptionParser::InvalidArgument, "#{key_file}: does not exist"
-  rescue OpenSSL::PKey::RSAError
-    raise OptionParser::InvalidArgument, "#{key_file}: invalid RSA key"
+  rescue OpenSSL::PKey::PKeyError, ArgumentError
+    raise OptionParser::InvalidArgument, "#{key_file}: invalid RSA, DSA, or EC key"
   end
 
   def execute
@@ -170,7 +175,8 @@ def build_key # :nodoc:
     raise Gem::CommandLineError,
           "Passphrase and passphrase confirmation don't match" unless passphrase == passphrase_confirmation
 
-    key      = Gem::Security.create_key
+    algorithm = options[:key_algorithm] || Gem::Security::DEFAULT_KEY_ALGORITHM
+    key = Gem::Security.create_key(algorithm)
     key_path = Gem::Security.write key, "gem-private_key.pem", 0600, passphrase
 
     return key, key_path
@@ -255,13 +261,14 @@ def load_default_key
     key_file = File.join Gem.default_key_path
     key = File.read key_file
     passphrase = ENV['GEM_PRIVATE_KEY_PASSPHRASE']
-    options[:key] = OpenSSL::PKey::RSA.new key, passphrase
+    options[:key] = OpenSSL::PKey.read key, passphrase
+
   rescue Errno::ENOENT
     alert_error \
       "--private-key not specified and ~/.gem/gem-private_key.pem does not exist"
 
     terminate_interaction 1
-  rescue OpenSSL::PKey::RSAError
+  rescue OpenSSL::PKey::PKeyError
     alert_error \
       "--private-key not specified and ~/.gem/gem-private_key.pem is not valid"
 

lib/rubygems/security.rb

@@ -152,6 +152,7 @@
 #                                      certificate for EMAIL_ADDR
 #     -C, --certificate CERT           Signing certificate for --sign
 #     -K, --private-key KEY            Key for --sign or --build
+#     -A, --key-algorithm ALGORITHM    Select key algorithm for --build from RSA, DSA, or EC. Defaults to RSA.
 #     -s, --sign CERT                  Signs CERT with the key from -K
 #                                      and the certificate from -C
 #     -d, --days NUMBER_OF_DAYS        Days before the certificate expires
@@ -317,7 +318,6 @@
 # * Honor extension restrictions
 # * Might be better to store the certificate chain as a PKCS#7 or PKCS#12
 #   file, instead of an array embedded in the metadata.
-# * Flexible signature and key algorithms, not hard-coded to RSA and SHA1.
 #
 # == Original author
 #
@@ -337,17 +337,19 @@ class Exception < Gem::Exception; end
   DIGEST_NAME = 'SHA256' # :nodoc:
 
   ##
-  # Algorithm for creating the key pair used to sign gems
+  # Length of keys created by RSA and DSA keys
 
-  KEY_ALGORITHM =
-    if defined?(OpenSSL::PKey::RSA)
-      OpenSSL::PKey::RSA
-    end
+  RSA_DSA_KEY_LENGTH = 3072
 
   ##
-  # Length of keys created by KEY_ALGORITHM
+  # Default algorithm to use when building a key pair
 
-  KEY_LENGTH = 3072
+  DEFAULT_KEY_ALGORITHM = 'RSA'
+
+  ##
+  # Named curve used for Elliptic Curve
+
+  EC_NAME = 'secp384r1'
 
   ##
   # Cipher used to encrypt the key pair used to sign gems.
@@ -400,7 +402,7 @@ def self.create_cert(subject, key, age = ONE_YEAR, extensions = EXTENSIONS,
                        serial = 1)
     cert = OpenSSL::X509::Certificate.new
 
-    cert.public_key = key.public_key
+    cert.public_key = get_public_key(key)
     cert.version    = 2
     cert.serial     = serial
 
@@ -418,6 +420,24 @@ def self.create_cert(subject, key, age = ONE_YEAR, extensions = EXTENSIONS,
     cert
   end
 
+  ##
+  # Gets the right public key from a PKey instance
+
+  def self.get_public_key(key)
+    return key.public_key unless key.is_a?(OpenSSL::PKey::EC)
+
+    ec_key = OpenSSL::PKey::EC.new(key.group.curve_name)
+    ec_key.public_key = key.public_key
+    ec_key
+  end
+
+  ##
+  # In Ruby 2.3 EC doesn't implement the private_key? but not the private? method
+
+  if defined?(OpenSSL::PKey::EC) && Gem::Version.new(String.new(RUBY_VERSION)) < Gem::Version.new("2.4.0")
+    OpenSSL::PKey::EC.send(:alias_method, :private?, :private_key?)
+  end
+
   ##
   # Creates a self-signed certificate with an issuer and subject from +email+,
   # a subject alternative name of +email+ and the given +extensions+ for the
@@ -459,11 +479,25 @@ def self.create_digest(algorithm = DIGEST_NAME)
   end
 
   ##
-  # Creates a new key pair of the specified +length+ and +algorithm+.  The
-  # default is a 3072 bit RSA key.
-
-  def self.create_key(length = KEY_LENGTH, algorithm = KEY_ALGORITHM)
-    algorithm.new length
+  # Creates a new key pair of the specified +algorithm+. RSA, DSA, and EC
+  # are supported.
+
+  def self.create_key(algorithm)
+    if defined?(OpenSSL::PKey)
+      case algorithm.downcase
+      when 'dsa'
+        OpenSSL::PKey::DSA.new(RSA_DSA_KEY_LENGTH)
+      when 'rsa'
+        OpenSSL::PKey::RSA.new(RSA_DSA_KEY_LENGTH)
+      when 'ec'
+        domain_key = OpenSSL::PKey::EC.new(EC_NAME)
+        domain_key.generate_key
+        domain_key
+      else
+        raise Gem::Security::Exception,
+        "#{algorithm} algorithm not found. RSA, DSA, and EC algorithms are supported."
+      end
+    end
   end
 
   ##
@@ -492,7 +526,7 @@ def self.re_sign(expired_certificate, private_key, age = ONE_YEAR,
     raise Gem::Security::Exception,
           "incorrect signing key for re-signing " +
           "#{expired_certificate.subject}" unless
-      expired_certificate.public_key.to_pem == private_key.public_key.to_pem
+      expired_certificate.public_key.to_pem == get_public_key(private_key).to_pem
 
     unless expired_certificate.subject.to_s ==
            expired_certificate.issuer.to_s

lib/rubygems/security/policy.rb

@@ -115,9 +115,11 @@ def check_key(signer, key)
       raise Gem::Security::Exception, 'missing key or signature'
     end
 
+    public_key = Gem::Security.get_public_key(key)
+
     raise Gem::Security::Exception,
       "certificate #{signer.subject} does not match the signing key" unless
-        signer.public_key.to_pem == key.public_key.to_pem
+        signer.public_key.to_pem == public_key.to_pem
 
     true
   end
@@ -164,9 +166,9 @@ def check_trust(chain, digester, trust_dir)
     end
 
     save_cert = OpenSSL::X509::Certificate.new File.read path
-    save_dgst = digester.digest save_cert.public_key.to_s
+    save_dgst = digester.digest save_cert.public_key.to_pem
 
-    pkey_str = root.public_key.to_s
+    pkey_str = root.public_key.to_pem
     cert_dgst = digester.digest pkey_str
 
     raise Gem::Security::Exception,

lib/rubygems/security/signer.rb

@@ -83,8 +83,8 @@ def initialize(key, cert_chain, passphrase = nil, options = {})
     @digest_name      = Gem::Security::DIGEST_NAME
     @digest_algorithm = Gem::Security.create_digest(@digest_name)
 
-    if @key && !@key.is_a?(OpenSSL::PKey::RSA)
-      @key = OpenSSL::PKey::RSA.new(File.read(@key), @passphrase)
+    if @key && !@key.is_a?(OpenSSL::PKey::PKey)
+      @key = OpenSSL::PKey.read(File.read(@key), @passphrase)
     end
 
     if @cert_chain
@@ -177,8 +177,7 @@ def re_sign_key(expiration_length: Gem::Security::ONE_YEAR) # :nodoc:
     disk_cert = File.read(disk_cert_path) rescue nil
 
     disk_key_path = File.join(Gem.default_key_path)
-    disk_key =
-      OpenSSL::PKey::RSA.new(File.read(disk_key_path), @passphrase) rescue nil
+    disk_key = OpenSSL::PKey.read(File.read(disk_key_path), @passphrase) rescue nil
 
     return unless disk_key
 

test/rubygems/helper.rb

@@ -1519,14 +1519,14 @@ def self.cert_path(cert_name)
   end
 
   ##
-  # Loads an RSA private key named +key_name+ with +passphrase+ in <tt>test/rubygems/</tt>
+  # Loads a private key named +key_name+ with +passphrase+ in <tt>test/rubygems/</tt>
 
   def self.load_key(key_name, passphrase = nil)
     key_file = key_path key_name
 
     key = File.read key_file
 
-    OpenSSL::PKey::RSA.new key, passphrase
+    OpenSSL::PKey.read key, passphrase
   end
 
   ##

test/rubygems/private_ec_key.pem

@@ -0,0 +1,9 @@
+-----BEGIN EC PRIVATE KEY-----
+Proc-Type: 4,ENCRYPTED
+DEK-Info: AES-256-CBC,4107F98A374CB8EC18F1AA4EA4B6A0DB
+
+BRklFxJGcz7gqQYxek8TZkt8qbPhB0FSR6nyw3SYuio/2tlT9ohs74mlK3EbG9Lt
+Y4OquJbksBFmoB7fIoM4vnuIZ0Eoz2ooxn9tjhBtqJ3mVscYXwZmA3UDUWDMlviQ
+Fu37OpikQv4TFA1jlmUK0LM8xmUCfUeLl0kHD17lFsz2gkO2kwg8mn/YUMOIaDOu
+EnnmxbAwnZBpemQkQfpTt2mYL9gu3CcMt5gokBuGDxY=
+-----END EC PRIVATE KEY-----

test/rubygems/test_gem_commands_cert_command.rb

@@ -14,9 +14,10 @@ class TestGemCommandsCertCommand < Gem::TestCase
   ALTERNATE_CERT = load_cert 'alternate'
   EXPIRED_PUBLIC_CERT = load_cert 'expired'
 
-  ALTERNATE_KEY_FILE = key_path 'alternate'
-  PRIVATE_KEY_FILE   = key_path 'private'
-  PUBLIC_KEY_FILE    = key_path 'public'
+  ALTERNATE_KEY_FILE  = key_path 'alternate'
+  PRIVATE_KEY_FILE    = key_path 'private'
+  PRIVATE_EC_KEY_FILE = key_path 'private_ec'
+  PUBLIC_KEY_FILE     = key_path 'public'
 
   ALTERNATE_CERT_FILE      = cert_path 'alternate'
   CHILD_CERT_FILE          = cert_path 'child'
@@ -142,6 +143,42 @@ def test_execute_build
     assert_path_exist File.join(@tempdir, 'gem-public_cert.pem')
   end
 
+  def test_execute_build_key_algorithm_ec_key
+    passphrase = 'Foo bar'
+
+    @cmd.handle_options %W[--build nobody@example.com --key-algorithm ec]
+
+    @build_ui = Gem::MockGemUi.new "#{passphrase}\n#{passphrase}"
+
+    use_ui @build_ui do
+      @cmd.execute
+    end
+
+    output = @build_ui.output.squeeze("\n").split "\n"
+
+    assert_equal "Passphrase for your Private Key:  ",
+                 output.shift
+    assert_equal "Please repeat the passphrase for your Private Key:  ",
+                 output.shift
+    assert_equal "Certificate: #{File.join @tempdir, 'gem-public_cert.pem'}",
+                 output.shift
+    assert_equal "Private Key: #{File.join @tempdir, 'gem-private_key.pem'}",
+                 output.shift
+
+    assert_equal "Don't forget to move the key file to somewhere private!",
+                 output.shift
+
+    assert_empty output
+    assert_empty @build_ui.error
+
+    assert_path_exist File.join(@tempdir, 'gem-private_key.pem')
+
+    cert_path = File.join(@tempdir, 'gem-public_cert.pem')
+    assert_path_exist cert_path
+    cert = OpenSSL::X509::Certificate.new(File.read(cert_path))
+    assert cert.public_key.is_a? OpenSSL::PKey::EC
+  end
+
   def test_execute_build_bad_email_address
     passphrase = 'Foo bar'
     email = "nobody@"
@@ -279,6 +316,28 @@ def test_execute_build_encrypted_key
     assert_path_exist File.join(@tempdir, 'gem-public_cert.pem')
   end
 
+  def test_execute_build_ec_key
+    @cmd.handle_options %W[
+      --build nobody@example.com
+      --private-key #{PRIVATE_EC_KEY_FILE}
+    ]
+
+    use_ui @ui do
+      @cmd.execute
+    end
+
+    output = @ui.output.split "\n"
+
+    assert_equal "Certificate: #{File.join @tempdir, 'gem-public_cert.pem'}",
+                 output.shift
+
+    assert_empty output
+    assert_empty @ui.error
+
+    assert_path_exist File.join(@tempdir, 'gem-public_cert.pem')
+    assert_path_not_exist File.join(@tempdir, 'gem-private_key.pem')
+  end
+
   def test_execute_certificate
     use_ui @ui do
       @cmd.handle_options %W[--certificate #{PUBLIC_CERT_FILE}]
@@ -742,7 +801,7 @@ def test_handle_options_key_bad
       @cmd.handle_options %W[--private-key #{bad}]
     end
 
-    assert_equal "invalid argument: --private-key #{bad}: invalid RSA key",
+    assert_equal "invalid argument: --private-key #{bad}: invalid RSA, DSA, or EC key",
                  e.message
 
     e = assert_raise OptionParser::InvalidArgument do