oidc-idp/cmd/idp/main.go

/*
Copyright 2020-2023 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

    https://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 main

import (
	"context"
	"crypto/tls"
	"crypto/x509"
	"encoding/base64"
	"errors"
	"fmt"
	"net/http"
	"net/url"
	"os"
	"os/signal"
	"sync/atomic"
	"time"

	"github.com/go-openapi/runtime/client"
	"github.com/gorilla/csrf"
	"github.com/knadh/koanf"
	hydra "github.com/ory/hydra-client-go/client"
	log "github.com/sirupsen/logrus"

	"code.cacert.org/cacert/oidc-idp/internal/handlers"
	"code.cacert.org/cacert/oidc-idp/internal/services"
	"code.cacert.org/cacert/oidc-idp/ui"
)

const (
	IdleTimeout     = 30 * time.Second
	ShutdownTimeout = 30 * time.Second
	ReadTimeOut     = 20 * time.Second
	WriteTimeOut    = 20 * time.Second

	DefaultCSRFMaxAge = 600

	httpsDefaultPort = 443
)

var (
	version = "local"
	commit  = "unknown"
	date    = "unknown"
)

func main() {
	logger := log.New()

	config, err := services.ConfigureApplication(logger, "IDP", services.DefaultConfig)
	if err != nil {
		logger.WithError(err).Fatal("error loading configuration")
	}

	if level := config.String("log.level"); level != "" {
		logLevel, err := log.ParseLevel(level)
		if err != nil {
			logger.WithError(err).Fatal("could not parse log level")
		}

		logger.SetLevel(logLevel)
	}

	if config.Bool("log.json") {
		logger.SetFormatter(&log.JSONFormatter{})
	}

	logger.WithFields(log.Fields{
		"version": version, "commit": commit, "date": date,
	}).Info("Starting CAcert OpenID Connect Identity Provider")
	logger.Infoln("Server is starting")
	bundle, catalog := services.InitI18n(logger, config.Strings("i18n.languages"))

	if err = services.AddMessages(catalog); err != nil {
		logger.WithError(err).Fatal("could not add messages for i18n")
	}

	clientTransport, err := configureAdminClient(config)
	if err != nil {
		logger.WithError(err).Fatal("could not configure Hydra admin client")
	}

	adminClient := hydra.New(clientTransport, nil)

	loginHandler := handlers.NewLoginHandler(logger, bundle, catalog, adminClient.Admin)
	consentHandler := handlers.NewConsentHandler(logger, bundle, catalog, adminClient.Admin)
	logoutHandler := handlers.NewLogoutHandler(logger, adminClient.Admin)

	logoutSuccessHandler := handlers.NewLogoutSuccessHandler(logger, bundle, catalog)
	errorHandler := handlers.NewErrorHandler(logger, bundle, catalog)
	staticFiles := http.FileServer(http.FS(ui.Static))

	router := http.NewServeMux()
	router.Handle("/login", loginHandler)
	router.Handle("/consent", consentHandler)
	router.Handle("/logout", logoutHandler)
	router.Handle("/error", errorHandler)
	router.Handle("/logout-successful", logoutSuccessHandler)
	router.Handle("/health", handlers.NewHealthHandler())
	router.Handle("/images/", staticFiles)
	router.Handle("/css/", staticFiles)
	router.Handle("/js/", staticFiles)

	csrfKey, err := base64.StdEncoding.DecodeString(config.MustString("security.csrf.key"))
	if err != nil {
		logger.WithError(err).Fatal("could not parse CSRF key bytes")
	}

	nextRequestID := func() string {
		return fmt.Sprintf("%d", time.Now().UnixNano())
	}

	tracing := handlers.Tracing(nextRequestID)
	logging := handlers.Logging(logger)
	hsts := handlers.EnableHSTS()
	csrfProtect := csrf.Protect(
		csrfKey,
		csrf.Secure(true),
		csrf.SameSite(csrf.SameSiteStrictMode),
		csrf.MaxAge(DefaultCSRFMaxAge))

	errorMiddleware, err := handlers.ErrorHandling(logger, ui.Templates, bundle, catalog)
	if err != nil {
		logger.WithError(err).Fatal("could not initialize request error handling")
	}

	handlerChain := tracing(logging(hsts(errorMiddleware(csrfProtect(router)))))

	startServer(logger, config, handlerChain)
}

func configureAdminClient(config *koanf.Koanf) (*client.Runtime, error) {
	adminURL, err := url.Parse(config.MustString("admin.url"))
	if err != nil {
		return nil, fmt.Errorf("error parsing admin URL: %w", err)
	}

	tlsClientConfig := &tls.Config{MinVersion: tls.VersionTLS12}

	if config.Exists("api-client.rootCAs") {
		rootCAFile := config.MustString("api-client.rootCAs")
		caCertPool := x509.NewCertPool()

		pemBytes, err := os.ReadFile(rootCAFile)
		if err != nil {
			return nil, fmt.Errorf("could not read CA certificate file: %w", err)
		}

		caCertPool.AppendCertsFromPEM(pemBytes)
		tlsClientConfig.RootCAs = caCertPool
	}

	tlsClientTransport := &http.Transport{TLSClientConfig: tlsClientConfig}
	httpClient := &http.Client{Transport: tlsClientTransport}
	clientTransport := client.NewWithClient(
		adminURL.Host,
		adminURL.Path,
		[]string{adminURL.Scheme},
		httpClient,
	)

	return clientTransport, nil
}

func startServer(logger *log.Logger, config *koanf.Koanf, handlerChain http.Handler) {
	clientCertificateCAFile := config.MustString("security.client.ca-file")
	serverBindAddress := config.String("server.bind_address")
	serverName := config.String("server.name")
	serverPort := config.Int("server.port")

	clientCertPool := x509.NewCertPool()

	pemBytes, err := os.ReadFile(clientCertificateCAFile)
	if err != nil {
		logger.WithError(err).Fatal("could not load client CA certificates")
	}

	clientCertPool.AppendCertsFromPEM(pemBytes)

	tlsConfig := &tls.Config{
		ServerName: serverName,
		MinVersion: tls.VersionTLS12,
		ClientAuth: tls.VerifyClientCertIfGiven,
		ClientCAs:  clientCertPool,
	}
	server := &http.Server{
		Addr:         fmt.Sprintf("%s:%d", serverBindAddress, serverPort),
		Handler:      handlerChain,
		ReadTimeout:  ReadTimeOut,
		WriteTimeout: WriteTimeOut,
		IdleTimeout:  IdleTimeout,
		TLSConfig:    tlsConfig,
	}

	done := make(chan bool)
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, os.Interrupt)

	go func() {
		<-quit
		logger.Infoln("Server is shutting down...")
		atomic.StoreInt32(&handlers.Healthy, 0)

		ctx, cancel := context.WithTimeout(context.Background(), ShutdownTimeout)
		defer cancel()

		server.SetKeepAlivesEnabled(false)

		if err := server.Shutdown(ctx); err != nil {
			logger.WithError(err).Fatal("Could not gracefully shutdown the server")
		}

		close(done)
	}()

	logger.WithFields(log.Fields{
		"address": server.Addr, "url": publicAddress(serverName, serverPort),
	}).Info("Server is ready to handle requests")
	atomic.StoreInt32(&handlers.Healthy, 1)

	if err := server.ListenAndServeTLS(
		config.String("server.certificate"), config.String("server.key"),
	); err != nil && !errors.Is(err, http.ErrServerClosed) {
		logger.WithError(err).WithField(
			"server_addr", server.Addr,
		).Fatal("Could not listen on configured server address")
	}

	<-done
	logger.Infoln("Server stopped")
}

func publicAddress(serverName string, serverPort int) string {
	if serverPort != httpsDefaultPort {
		return fmt.Sprintf("https://%s:%d/", serverName, serverPort)
	}

	return fmt.Sprintf("https://%s/", serverName)
}