cacert-gosigner/internal/x509/signing/signing_test.go

/*
Copyright 2021-2022 CAcert Inc.
SPDX-License-Identifier: Apache-2.0

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package signing_test

import (
	"crypto"
	"crypto/ecdsa"
	"crypto/elliptic"
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"crypto/x509/pkix"
	"fmt"
	"math/big"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"

	"git.cacert.org/cacert-gosigner/internal/x509/helper"
	"git.cacert.org/cacert-gosigner/internal/x509/signing"
)

func randomSerial(t *testing.T) *big.Int {
	t.Helper()

	serial, err := helper.GenerateRandomSerial()
	if err != nil {
		t.Fatal(err)
	}

	return serial
}

func TestProfileUsage_String(t *testing.T) {
	okValues := []struct {
		Name  string
		Usage signing.ProfileUsage
	}{
		{"invalid", signing.UsageInvalid},
		{"ocsp", signing.UsageOCSP},
		{"client", signing.UsageClient},
		{"code", signing.UsageCode},
		{"person", signing.UsagePerson},
		{"server", signing.UsageServer},
		{"server-client", signing.UsageServerClient},
		{"org-client", signing.UsageOrgClient},
		{"org-code", signing.UsageOrgCode},
		{"org-email", signing.UsageOrgEmail},
		{"org-person", signing.UsageOrgPerson},
		{"org-server", signing.UsageOrgServer},
		{"org-server-client", signing.UsageOrgServerClient},
	}

	for _, v := range okValues {
		t.Run(v.Name, func(t *testing.T) {
			str := v.Usage.String()

			assert.NotEmpty(t, str)
			assert.NotContains(t, str, "unknown profile usage")
		})
	}

	t.Run("undefined", func(t *testing.T) {
		str := signing.ProfileUsage(255).String()

		assert.NotEmpty(t, str)
		assert.Contains(t, str, "unknown profile usage")
		assert.Contains(t, str, "255")
	})
}

func TestProfileUsage_Description(t *testing.T) {
	okValues := []struct {
		Name  string
		Usage signing.ProfileUsage
	}{
		{"invalid", signing.UsageInvalid},
		{"ocsp", signing.UsageOCSP},
		{"client", signing.UsageClient},
		{"code", signing.UsageCode},
		{"person", signing.UsagePerson},
		{"server", signing.UsageServer},
		{"server-client", signing.UsageServerClient},
		{"org-client", signing.UsageOrgClient},
		{"org-code", signing.UsageOrgCode},
		{"org-email", signing.UsageOrgEmail},
		{"org-person", signing.UsageOrgPerson},
		{"org-server", signing.UsageOrgServer},
		{"org-server-client", signing.UsageOrgServerClient},
	}

	for _, v := range okValues {
		t.Run(v.Name, func(t *testing.T) {
			str := v.Usage.Description()

			assert.NotEmpty(t, str)
			assert.NotContains(t, str, "unknown profile usage")
			assert.Greater(t, len(str), len(v.Name))
		})
	}

	t.Run("undefined", func(t *testing.T) {
		str := signing.ProfileUsage(255).Description()

		assert.NotEmpty(t, str)
		assert.Contains(t, str, "unknown profile usage")
		assert.Contains(t, str, "255")
	})
}

type testRepo struct {
	certs map[string]x509.Certificate
}

func (r *testRepo) StoreCertificate(certificate *x509.Certificate) error {
	r.certs[certificate.SerialNumber.Text(16)] = *certificate

	return nil
}

type testSigner struct {
	t           *testing.T
	key         crypto.PrivateKey
	certificate *x509.Certificate
}

func newTestSignerResponse(certificate *x509.Certificate) *signing.SignerResponse {
	return &signing.SignerResponse{Certificate: certificate}
}

func (s *testSigner) SignCertificate(request *signing.SignerRequest) (*signing.SignerResponse, error) {
	startDate := time.Now().Add(-1 * time.Minute)
	template := &x509.Certificate{
		Subject:            request.SubjectDN,
		SerialNumber:       randomSerial(s.t),
		EmailAddresses:     request.Emails,
		NotBefore:          startDate,
		NotAfter:           startDate.AddDate(1, 0, 0),
		KeyUsage:           x509.KeyUsageDigitalSignature | x509.KeyUsageDataEncipherment,
		ExtKeyUsage:        []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth, x509.ExtKeyUsageEmailProtection},
		SignatureAlgorithm: s.determineSignatureAlgorithm(request.PreferredHash),
	}

	certBytes, err := x509.CreateCertificate(rand.Reader, template, s.certificate, request.CSR.PublicKey, s.key)
	if err != nil {
		return nil, fmt.Errorf("could not sign certificate: %w", err)
	}

	certificate, err := x509.ParseCertificate(certBytes)
	if err != nil {
		return nil, fmt.Errorf("could not parse certificate: %w", err)
	}

	return newTestSignerResponse(certificate), nil
}

func (s *testSigner) determineSignatureAlgorithm(hash crypto.Hash) x509.SignatureAlgorithm {
	switch hash {
	case crypto.SHA512:
		return x509.ECDSAWithSHA512
	case crypto.SHA384:
		return x509.ECDSAWithSHA384
	default:
		return x509.ECDSAWithSHA384
	}
}

func TestSigning(t *testing.T) {
	testRepository := testRepo{certs: make(map[string]x509.Certificate)}
	testSigner := newTestSigner(t)
	s := signing.NewX509Signing(testSigner, &testRepository)

	csrKey, err := rsa.GenerateKey(rand.Reader, 3072)
	if err != nil {
		t.Errorf("could not generate key pair")
	}

	csrTemplate := &x509.CertificateRequest{PublicKey: csrKey.Public()}

	testRequest := &signing.SignerRequest{
		CSR:           csrTemplate,
		SubjectDN:     pkix.Name{CommonName: "Test Subject"},
		Emails:        []string{"test@example.org"},
		DNSNames:      nil,
		PreferredHash: crypto.SHA384,
	}

	signed, err := s.Sign(testRequest)
	if err != nil {
		t.Error(err)
	}

	cert := signed.Certificate
	assert.Contains(t, testRepository.certs, cert.SerialNumber.Text(16))
	assert.Equal(t, cert.Subject.CommonName, "Test Subject")
	assert.Contains(t, cert.EmailAddresses, "test@example.org")
}

func newTestSigner(t *testing.T) *testSigner {
	t.Helper()

	caKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
	if err != nil {
		t.Fatalf("could not generate key pair: %v", err)
	}

	caTemplate := &x509.Certificate{Subject: pkix.Name{CommonName: "Test CA"}, SerialNumber: randomSerial(t)}

	certificateBytes, err := x509.CreateCertificate(rand.Reader, caTemplate, caTemplate, caKey.Public(), caKey)
	if err != nil {
		t.Fatalf("could not self-sign CA certificate: %v", err)
	}

	caCertificate, err := x509.ParseCertificate(certificateBytes)
	if err != nil {
		t.Fatalf("could not create test CA certificate: %v", err)
	}

	return &testSigner{key: caKey, certificate: caCertificate, t: t}
}