certificates/ca/ca.go
2021-04-16 13:25:01 +02:00

422 lines
12 KiB
Go

package ca
import (
"crypto/tls"
"crypto/x509"
"fmt"
"log"
"net/http"
"net/url"
"reflect"
"sync"
"github.com/go-chi/chi"
"github.com/pkg/errors"
"github.com/smallstep/certificates/acme"
acmeAPI "github.com/smallstep/certificates/acme/api"
acmeNoSQL "github.com/smallstep/certificates/acme/db/nosql"
"github.com/smallstep/certificates/api"
"github.com/smallstep/certificates/authority"
"github.com/smallstep/certificates/db"
"github.com/smallstep/certificates/logging"
"github.com/smallstep/certificates/monitoring"
"github.com/smallstep/certificates/scep"
scepAPI "github.com/smallstep/certificates/scep/api"
"github.com/smallstep/certificates/server"
"github.com/smallstep/nosql"
)
type options struct {
configFile string
password []byte
issuerPassword []byte
database db.AuthDB
}
func (o *options) apply(opts []Option) {
for _, fn := range opts {
fn(o)
}
}
// Option is the type of options passed to the CA constructor.
type Option func(o *options)
// WithConfigFile sets the given name as the configuration file name in the CA
// options.
func WithConfigFile(name string) Option {
return func(o *options) {
o.configFile = name
}
}
// WithPassword sets the given password as the configured password in the CA
// options.
func WithPassword(password []byte) Option {
return func(o *options) {
o.password = password
}
}
// WithIssuerPassword sets the given password as the configured certificate
// issuer password in the CA options.
func WithIssuerPassword(password []byte) Option {
return func(o *options) {
o.issuerPassword = password
}
}
// WithDatabase sets the given authority database to the CA options.
func WithDatabase(db db.AuthDB) Option {
return func(o *options) {
o.database = db
}
}
// CA is the type used to build the complete certificate authority. It builds
// the HTTP server, set ups the middlewares and the HTTP handlers.
type CA struct {
auth *authority.Authority
config *authority.Config
srv *server.Server
insecureSrv *server.Server
opts *options
renewer *TLSRenewer
}
// New creates and initializes the CA with the given configuration and options.
func New(config *authority.Config, opts ...Option) (*CA, error) {
ca := &CA{
config: config,
opts: new(options),
}
ca.opts.apply(opts)
return ca.Init(config)
}
// Init initializes the CA with the given configuration.
func (ca *CA) Init(config *authority.Config) (*CA, error) {
// Intermediate Password.
if len(ca.opts.password) > 0 {
ca.config.Password = string(ca.opts.password)
}
// Certificate issuer password for RA mode.
if len(ca.opts.issuerPassword) > 0 {
if ca.config.AuthorityConfig != nil && ca.config.AuthorityConfig.CertificateIssuer != nil {
ca.config.AuthorityConfig.CertificateIssuer.Password = string(ca.opts.issuerPassword)
}
}
var opts []authority.Option
if ca.opts.database != nil {
opts = append(opts, authority.WithDatabase(ca.opts.database))
}
auth, err := authority.New(config, opts...)
if err != nil {
return nil, err
}
ca.auth = auth
tlsConfig, err := ca.getTLSConfig(auth)
if err != nil {
return nil, err
}
// Using chi as the main router
mux := chi.NewRouter()
handler := http.Handler(mux)
insecureMux := chi.NewRouter()
insecureHandler := http.Handler(insecureMux)
// Add regular CA api endpoints in / and /1.0
routerHandler := api.New(auth)
routerHandler.Route(mux)
mux.Route("/1.0", func(r chi.Router) {
routerHandler.Route(r)
})
//Add ACME api endpoints in /acme and /1.0/acme
dns := config.DNSNames[0]
u, err := url.Parse("https://" + config.Address)
if err != nil {
return nil, err
}
port := u.Port()
if port != "" && port != "443" {
dns = fmt.Sprintf("%s:%s", dns, port)
}
prefix := "acme"
var acmeDB acme.DB
if config.DB == nil {
acmeDB = nil
} else {
acmeDB, err = acmeNoSQL.New(auth.GetDatabase().(nosql.DB))
if err != nil {
return nil, errors.Wrap(err, "error configuring ACME DB interface")
}
}
acmeHandler := acmeAPI.NewHandler(acmeAPI.HandlerOptions{
Backdate: *config.AuthorityConfig.Backdate,
DB: acmeDB,
DNS: dns,
Prefix: prefix,
CA: auth,
})
mux.Route("/"+prefix, func(r chi.Router) {
acmeHandler.Route(r)
})
// Use 2.0 because, at the moment, our ACME api is only compatible with v2.0
// of the ACME spec.
mux.Route("/2.0/"+prefix, func(r chi.Router) {
acmeHandler.Route(r)
})
if ca.shouldServeSCEPEndpoints() {
scepPrefix := "scep"
scepAuthority, err := scep.New(auth, scep.AuthorityOptions{
Service: auth.GetSCEPService(),
DNS: dns,
Prefix: scepPrefix,
})
if err != nil {
return nil, errors.Wrap(err, "error creating SCEP authority")
}
scepRouterHandler := scepAPI.New(scepAuthority)
// According to the RFC (https://tools.ietf.org/html/rfc8894#section-7.10),
// SCEP operations are performed using HTTP, so that's why the API is mounted
// to the insecure mux.
insecureMux.Route("/"+scepPrefix, func(r chi.Router) {
scepRouterHandler.Route(r)
})
// The RFC also mentions usage of HTTPS, but seems to advise
// against it, because of potential interoperability issues.
// Currently I think it's not bad to use HTTPS also, so that's
// why I've kept the API endpoints in both muxes and both HTTP
// as well as HTTPS can be used to request certificates
// using SCEP.
mux.Route("/"+scepPrefix, func(r chi.Router) {
scepRouterHandler.Route(r)
})
}
// helpful routine for logging all routes
//dumpRoutes(mux)
// Add monitoring if configured
if len(config.Monitoring) > 0 {
m, err := monitoring.New(config.Monitoring)
if err != nil {
return nil, err
}
handler = m.Middleware(handler)
insecureHandler = m.Middleware(insecureHandler)
}
// Add logger if configured
if len(config.Logger) > 0 {
logger, err := logging.New("ca", config.Logger)
if err != nil {
return nil, err
}
handler = logger.Middleware(handler)
insecureHandler = logger.Middleware(insecureHandler)
}
ca.srv = server.New(config.Address, handler, tlsConfig)
// only start the insecure server if the insecure address is configured
// and, currently, also only when it should serve SCEP endpoints.
if ca.shouldServeSCEPEndpoints() && config.InsecureAddress != "" {
// TODO: instead opt for having a single server.Server but two
// http.Servers handling the HTTP and HTTPS handler? The latter
// will probably introduce more complexity in terms of graceful
// reload.
ca.insecureSrv = server.New(config.InsecureAddress, insecureHandler, nil)
}
return ca, nil
}
// Run starts the CA calling to the server ListenAndServe method.
func (ca *CA) Run() error {
var wg sync.WaitGroup
errors := make(chan error, 1)
if ca.insecureSrv != nil {
wg.Add(1)
go func() {
defer wg.Done()
errors <- ca.insecureSrv.ListenAndServe()
}()
}
wg.Add(1)
go func() {
defer wg.Done()
errors <- ca.srv.ListenAndServe()
}()
// wait till error occurs; ensures the servers keep listening
err := <-errors
wg.Wait()
return err
}
// Stop stops the CA calling to the server Shutdown method.
func (ca *CA) Stop() error {
ca.renewer.Stop()
if err := ca.auth.Shutdown(); err != nil {
log.Printf("error stopping ca.Authority: %+v\n", err)
}
var insecureShutdownErr error
if ca.insecureSrv != nil {
insecureShutdownErr = ca.insecureSrv.Shutdown()
}
secureErr := ca.srv.Shutdown()
if insecureShutdownErr != nil {
return insecureShutdownErr
}
return secureErr
}
// Reload reloads the configuration of the CA and calls to the server Reload
// method.
func (ca *CA) Reload() error {
config, err := authority.LoadConfiguration(ca.opts.configFile)
if err != nil {
return errors.Wrap(err, "error reloading ca configuration")
}
logContinue := func(reason string) {
log.Println(reason)
log.Println("Continuing to run with the original configuration.")
log.Println("You can force a restart by sending a SIGTERM signal and then restarting the step-ca.")
}
// Do not allow reload if the database configuration has changed.
if !reflect.DeepEqual(ca.config.DB, config.DB) {
logContinue("Reload failed because the database configuration has changed.")
return errors.New("error reloading ca: database configuration cannot change")
}
newCA, err := New(config,
WithPassword(ca.opts.password),
WithIssuerPassword(ca.opts.issuerPassword),
WithConfigFile(ca.opts.configFile),
WithDatabase(ca.auth.GetDatabase()),
)
if err != nil {
logContinue("Reload failed because the CA with new configuration could not be initialized.")
return errors.Wrap(err, "error reloading ca")
}
if ca.insecureSrv != nil {
if err = ca.insecureSrv.Reload(newCA.insecureSrv); err != nil {
logContinue("Reload failed because insecure server could not be replaced.")
return errors.Wrap(err, "error reloading insecure server")
}
}
if err = ca.srv.Reload(newCA.srv); err != nil {
logContinue("Reload failed because server could not be replaced.")
return errors.Wrap(err, "error reloading server")
}
// 1. Stop previous renewer
// 2. Safely shutdown any internal resources (e.g. key manager)
// 3. Replace ca properties
// Do not replace ca.srv
ca.renewer.Stop()
ca.auth.CloseForReload()
ca.auth = newCA.auth
ca.config = newCA.config
ca.opts = newCA.opts
ca.renewer = newCA.renewer
return nil
}
// getTLSConfig returns a TLSConfig for the CA server with a self-renewing
// server certificate.
func (ca *CA) getTLSConfig(auth *authority.Authority) (*tls.Config, error) {
// Create initial TLS certificate
tlsCrt, err := auth.GetTLSCertificate()
if err != nil {
return nil, err
}
// Start tls renewer with the new certificate.
// If a renewer was started, attempt to stop it before.
if ca.renewer != nil {
ca.renewer.Stop()
}
ca.renewer, err = NewTLSRenewer(tlsCrt, auth.GetTLSCertificate)
if err != nil {
return nil, err
}
ca.renewer.Run()
var tlsConfig *tls.Config
if ca.config.TLS != nil {
tlsConfig = ca.config.TLS.TLSConfig()
} else {
tlsConfig = &tls.Config{
MinVersion: tls.VersionTLS12,
}
}
certPool := x509.NewCertPool()
for _, crt := range auth.GetRootCertificates() {
certPool.AddCert(crt)
}
// GetCertificate will only be called if the client supplies SNI
// information or if tlsConfig.Certificates is empty.
// When client requests are made using an IP address (as opposed to a domain
// name) the server does not receive any SNI and may fallback to using the
// first entry in the Certificates attribute; by setting the attribute to
// empty we are implicitly forcing GetCertificate to be the only mechanism
// by which the server can find it's own leaf Certificate.
tlsConfig.Certificates = []tls.Certificate{}
tlsConfig.GetCertificate = ca.renewer.GetCertificateForCA
// Add support for mutual tls to renew certificates
tlsConfig.ClientAuth = tls.VerifyClientCertIfGiven
tlsConfig.ClientCAs = certPool
// Use server's most preferred ciphersuite
tlsConfig.PreferServerCipherSuites = true
return tlsConfig, nil
}
// shouldMountSCEPEndpoints returns if the CA should be
// configured with endpoints for SCEP. This is assumed to be
// true if a SCEPService exists, which is true in case a
// SCEP provisioner was configured.
func (ca *CA) shouldServeSCEPEndpoints() bool {
return ca.auth.GetSCEPService() != nil
}
//nolint // ignore linters to allow keeping this function around for debugging
func dumpRoutes(mux chi.Routes) {
// helpful routine for logging all routes //
walkFunc := func(method string, route string, handler http.Handler, middlewares ...func(http.Handler) http.Handler) error {
fmt.Printf("%s %s\n", method, route)
return nil
}
if err := chi.Walk(mux, walkFunc); err != nil {
fmt.Printf("Logging err: %s\n", err.Error())
}
}