Merge branch 'develop'

1 files changed, 232 insertions, 0 deletions

diff --git a/lib/leap_cli/x509/certs.rb b/lib/leap_cli/x509/certs.rb
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+++ b/lib/leap_cli/x509/certs.rb
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+
+module LeapCli; module X509
+
+  #
+  # returns a fingerprint of a x509 certificate
+  #
+  # Note: there are different ways of computing a digest of a certificate.
+  # You can either take a digest of the entire cert in DER format, or you
+  # can take a digest of the public key.
+  #
+  # For now, we only support the DER method.
+  #
+  def self.fingerprint(digest, cert_file)
+    if cert_file.is_a? String
+      cert = OpenSSL::X509::Certificate.new(Util.read_file!(cert_file))
+    elsif cert_file.is_a? OpenSSL::X509::Certificate
+      cert = cert_file
+    elsif cert_file.is_a? CertificateAuthority::Certificate
+      cert = cert_file.openssl_body
+    end
+    digester = case digest
+      when "MD5" then Digest::MD5.new
+      when "SHA1" then Digest::SHA1.new
+      when "SHA256" then Digest::SHA256.new
+      when "SHA384" then Digest::SHA384.new
+      when "SHA512" then Digest::SHA512.new
+    end
+    digester.hexdigest(cert.to_der)
+  end
+
+  def self.ca_root
+    @ca_root ||= begin
+      load_certificate_file(:ca_cert, :ca_key)
+    end
+  end
+
+  def self.client_ca_root
+    @client_ca_root ||= begin
+      load_certificate_file(:client_ca_cert, :client_ca_key)
+    end
+  end
+
+  def self.load_certificate_file(crt_file, key_file=nil, password=nil)
+    crt = Util.read_file!(crt_file)
+    openssl_cert = OpenSSL::X509::Certificate.new(crt)
+    cert = CertificateAuthority::Certificate.from_openssl(openssl_cert)
+    if key_file
+      key = Util.read_file!(key_file)
+      cert.key_material.private_key = OpenSSL::PKey::RSA.new(key, password)
+    end
+    return cert
+  end
+
+  #
+  # creates a new certificate authority.
+  #
+  def self.new_ca(options, common_name)
+    root = CertificateAuthority::Certificate.new
+
+    # set subject
+    root.subject.common_name = common_name
+    possible = ['country', 'state', 'locality', 'organization', 'organizational_unit', 'email_address']
+    options.keys.each do |key|
+      if possible.include?(key)
+        root.subject.send(key + '=', options[key])
+      end
+    end
+
+    # set expiration
+    root.not_before = X509.yesterday
+    root.not_after = X509.yesterday_advance(options['life_span'])
+
+    # generate private key
+    root.serial_number.number = 1
+    root.key_material.generate_key(options['bit_size'])
+
+    # sign self
+    root.signing_entity = true
+    root.parent = root
+    root.sign!(ca_root_signing_profile)
+    return root
+  end
+
+  #
+  # creates a CSR in memory and returns it.
+  # with the correct extReq attribute so that the CA
+  # doens't generate certs with extensions we don't want.
+  #
+  def self.new_csr(dn, keypair, digest)
+    csr = CertificateAuthority::SigningRequest.new
+    csr.distinguished_name = dn
+    csr.key_material = keypair
+    csr.digest = digest
+
+    # define extensions manually (library doesn't support setting these on CSRs)
+    extensions = []
+    extensions << CertificateAuthority::Extensions::BasicConstraints.new.tap {|basic|
+      basic.ca = false
+    }
+    extensions << CertificateAuthority::Extensions::KeyUsage.new.tap {|keyusage|
+      keyusage.usage = ["digitalSignature", "keyEncipherment"]
+    }
+    extensions << CertificateAuthority::Extensions::ExtendedKeyUsage.new.tap {|extkeyusage|
+      extkeyusage.usage = [ "serverAuth"]
+    }
+
+    # convert extensions to attribute 'extReq'
+    # aka "Requested Extensions"
+    factory = OpenSSL::X509::ExtensionFactory.new
+    attrval = OpenSSL::ASN1::Set([OpenSSL::ASN1::Sequence(
+      extensions.map{|e| factory.create_ext(e.openssl_identifier, e.to_s, e.critical)}
+    )])
+    attrs = [
+      OpenSSL::X509::Attribute.new("extReq", attrval),
+    ]
+    csr.attributes = attrs
+
+    return csr
+  end
+
+  #
+  # creates new csr and cert files for a particular domain.
+  #
+  # The cert is signed with the ca_root, but should be replaced
+  # later with a real cert signed by a better ca
+  #
+  def self.create_csr_and_cert(options)
+    bit_size = options[:bits].to_i
+    digest   = options[:digest]
+
+    # RSA key
+    keypair = CertificateAuthority::MemoryKeyMaterial.new
+    Util.log :generating, "%s bit RSA key" % bit_size do
+      keypair.generate_key(bit_size)
+      Util.write_file! [:commercial_key, options[:domain]], keypair.private_key.to_pem
+    end
+
+    # CSR
+    csr = nil
+    dn  = CertificateAuthority::DistinguishedName.new
+    dn.common_name   = options[:domain]
+    dn.organization  = options[:organization]
+    dn.ou            = options[:organizational_unit]
+    dn.email_address = options[:email]
+    dn.country       = options[:country]
+    dn.state         = options[:state]
+    dn.locality      = options[:locality]
+    Util.log :generating, "CSR with #{digest} digest and #{print_dn(dn)}" do
+      csr = new_csr(dn, keypair, options[:digest])
+      Util.write_file! [:commercial_csr, options[:domain]], csr.to_pem
+    end
+
+    # Sign using our own CA, for use in testing but hopefully not production.
+    # It is not that commerical CAs are so secure, it is just that signing your own certs is
+    # a total drag for the user because they must click through dire warnings.
+    Util.log :generating, "self-signed x509 server certificate for testing purposes" do
+      cert = csr.to_cert
+      cert.serial_number.number = cert_serial_number(options[:domain])
+      cert.not_before = yesterday
+      cert.not_after  = yesterday.advance(:years => 1)
+      cert.parent = ca_root
+      cert.sign! domain_test_signing_profile
+      Util.write_file! [:commercial_cert, options[:domain]], cert.to_pem
+      Util.log "please replace this file with the real certificate you get from a CA using #{Path.relative_path([:commercial_csr, options[:domain]])}"
+    end
+
+    # Fake CA
+    unless Util.file_exists? :commercial_ca_cert
+      Util.log :using, "generated CA in place of commercial CA for testing purposes" do
+        Util.write_file! :commercial_ca_cert, Util.read_file!(:ca_cert)
+        Util.log "please also replace this file with the CA cert from the commercial authority you use."
+      end
+    end
+  end
+
+  #
+  # Return true if the given server cert has been signed by the given CA cert
+  #
+  # This does not actually validate the signature, it just checks the cert
+  # extensions.
+  #
+  def self.created_by_authority?(cert, ca=X509.ca_root)
+    authority_key_id = cert.extensions["authorityKeyIdentifier"].identifier.sub(/^keyid:/, '')
+    return authority_key_id == self.public_key_id_for_ca(ca)
+  end
+
+  #
+  # For cert serial numbers, we need a non-colliding number less than 160 bits.
+  # md5 will do nicely, since there is no need for a secure hash, just a short one.
+  # (md5 is 128 bits)
+  #
+  def self.cert_serial_number(domain_name)
+    Digest::MD5.hexdigest("#{domain_name} -- #{Time.now}").to_i(16)
+  end
+
+  #
+  # for the random common name, we need a text string that will be
+  # unique across all certs.
+  #
+  def self.random_common_name(domain_name)
+    #cert_serial_number(domain_name).to_s(36)
+    SecureRandom.uuid
+  end
+
+  private
+
+  #
+  # calculate the "key id" for a root CA, that matches the value
+  # Authority Key Identifier in the x509 extensions of a cert.
+  #
+  def self.public_key_id_for_ca(ca_cert)
+    @ca_key_ids ||= {}
+    @ca_key_ids[ca_cert.object_id] ||= begin
+      pubkey = ca_cert.key_material.public_key
+      seq = OpenSSL::ASN1::Sequence([
+        OpenSSL::ASN1::Integer.new(pubkey.n),
+        OpenSSL::ASN1::Integer.new(pubkey.e)
+      ])
+      Digest::SHA1.hexdigest(seq.to_der).upcase.scan(/../).join(':')
+    end
+  end
+
+  # prints CertificateAuthority::DistinguishedName fields
+  def self.print_dn(dn)
+    fields = {}
+    [:common_name, :locality, :state, :country, :organization, :organizational_unit, :email_address].each do |attr|
+      fields[attr] = dn.send(attr) if dn.send(attr)
+    end
+    fields.inspect
+  end
+
+end; end