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package cautils
import (
"context"
"crypto/rand"
"crypto/x509"
"crypto/x509/pkix"
"encoding/json"
"encoding/pem"
"fmt"
"io/ioutil"
"net/http"
"os"
"strings"
"time"
"github.com/pkg/errors"
"github.com/smallstep/certificates/acme"
acmeAPI "github.com/smallstep/certificates/acme/api"
"github.com/smallstep/certificates/ca"
"github.com/smallstep/certificates/pki"
"github.com/smallstep/cli/crypto/keys"
"github.com/smallstep/cli/errs"
"github.com/smallstep/cli/flags"
"github.com/smallstep/cli/jose"
"github.com/smallstep/cli/ui"
"github.com/smallstep/cli/utils"
"github.com/urfave/cli"
)
func startHTTPServer(addr string, token string, keyAuth string) *http.Server {
srv := &http.Server{Addr: addr}
http.HandleFunc(fmt.Sprintf("/.well-known/acme-challenge/%s", token), func(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "application/octet-stream")
w.Write([]byte(keyAuth))
})
go func() {
// returns ErrServerClosed on graceful close
if err := srv.ListenAndServe(); err != http.ErrServerClosed {
// NOTE: there is a chance that next line won't have time to run,
// as main() doesn't wait for this goroutine to stop. don't use
// code with race conditions like these for production. see post
// comments below on more discussion on how to handle this.
ui.Printf("\nListenAndServe(): %s\n", err)
}
}()
// returning reference so caller can call Shutdown()
return srv
}
type issueMode interface {
Run() error
Cleanup() error
}
type standaloneMode struct {
identifier, token string
key *jose.JSONWebKey
listenAddr string
srv *http.Server
}
func newStandaloneMode(identifier, listenAddr, token string, key *jose.JSONWebKey) *standaloneMode {
return &standaloneMode{
identifier: identifier,
listenAddr: listenAddr,
token: token,
key: key,
}
}
func (sm *standaloneMode) Run() error {
ui.Printf("Using Standalone Mode HTTP challenge to validate %s", sm.identifier)
keyAuth, err := acme.KeyAuthorization(sm.token, sm.key)
if err != nil {
return errors.Wrap(err, "error generating ACME key authorization")
}
sm.srv = startHTTPServer(sm.listenAddr, sm.token, keyAuth)
return nil
}
func (sm *standaloneMode) Cleanup() error {
ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
defer cancel()
return errors.Wrap(sm.srv.Shutdown(ctx), "error gracefully shutting down server")
}
type webrootMode struct {
dir, token, identifier string
key *jose.JSONWebKey
}
func newWebrootMode(dir, token, identifier string, key *jose.JSONWebKey) *webrootMode {
return &webrootMode{
dir: dir,
token: token,
identifier: identifier,
key: key,
}
}
func (wm *webrootMode) Run() error {
ui.Printf("Using Webroot Mode HTTP challenge to validate %s", wm.identifier)
keyAuth, err := acme.KeyAuthorization(wm.token, wm.key)
if err != nil {
return errors.Wrap(err, "error generating ACME key authorization")
}
_, err = os.Stat(wm.dir)
switch {
case os.IsNotExist(err):
return errors.Errorf("webroot directory %s does not exist", wm.dir)
case err != nil:
return errors.Wrapf(err, "error checking for directory %s", wm.dir)
}
// Use 0755 and 0644 (rather than 0700 and 0600) for directory and file
// respectively because the process running the file server, and therefore
// reading/serving the file, may be owned by a different user than
// the one running the `step` command that will write the file.
chPath := fmt.Sprintf("%s/.well-known/acme-challenge", wm.dir)
if _, err = os.Stat(chPath); os.IsNotExist(err) {
if err = os.MkdirAll(chPath, 0755); err != nil {
return errors.Wrapf(err, "error creating directory path %s", chPath)
}
}
return errors.Wrapf(ioutil.WriteFile(fmt.Sprintf("%s/%s", chPath, wm.token), []byte(keyAuth), 0644),
"error writing key authorization file %s", chPath+wm.token)
}
func (wm *webrootMode) Cleanup() error {
return errors.Wrap(os.Remove(fmt.Sprintf("%s/.well-known/acme-challenge/%s",
wm.dir, wm.token)), "error removing ACME challenge file")
}
func serveAndValidateHTTPChallenge(ctx *cli.Context, ac *ca.ACMEClient, ch *acme.Challenge, identifier string) error {
var mode issueMode
if ctx.Bool("standalone") {
mode = newStandaloneMode(identifier, ctx.String("http-listen"), ch.Token, ac.Key)
} else {
mode = newWebrootMode(ctx.String("webroot"), ch.Token, identifier, ac.Key)
}
if err := mode.Run(); err != nil {
ui.Printf(" Error!\n\n")
mode.Cleanup()
return err
}
ui.Printf(" .") // Indicates passage of time.
if err := ac.ValidateChallenge(ch.URL); err != nil {
ui.Printf(" Error!\n\n")
mode.Cleanup()
return errors.Wrapf(err, "error validating ACME Challenge at %s", ch.URL)
}
var (
isValid = false
vch *acme.Challenge
err error
)
for attempts := 0; attempts < 10; attempts++ {
time.Sleep(1 * time.Second)
ui.Printf(".")
vch, err = ac.GetChallenge(ch.URL)
if err != nil {
ui.Printf(" Error!\n\n")
mode.Cleanup()
return errors.Wrapf(err, "error retrieving ACME Challenge at %s", ch.URL)
}
if vch.Status == "valid" {
isValid = true
break
}
}
if !isValid {
ui.Printf(" Error!\n\n")
mode.Cleanup()
return errors.Errorf("Unable to validate challenge: %+v", vch)
}
if err := mode.Cleanup(); err != nil {
return err
}
ui.Printf(" done!\n")
return nil
}
func authorizeOrder(ctx *cli.Context, ac *ca.ACMEClient, o *acme.Order) error {
for _, azURL := range o.AuthorizationURLs {
az, err := ac.GetAuthz(azURL)
if err != nil {
return errors.Wrapf(err, "error retrieving ACME Authz at %s", azURL)
}
ident := az.Identifier.Value
if az.Wildcard {
ident = "*." + ident
}
chValidated := false
for _, ch := range az.Challenges {
// TODO: Allow other types of challenges (not just http).
if ch.Type == "http-01" {
if err := serveAndValidateHTTPChallenge(ctx, ac, ch, ident); err != nil {
return err
}
chValidated = true
break
}
}
if !chValidated {
return errors.Errorf("unable to validate any challenges for identifier: %s", ident)
}
}
return nil
}
func finalizeOrder(ac *ca.ACMEClient, o *acme.Order, csr *x509.CertificateRequest) (*acme.Order, error) {
var (
err error
ro, fo *acme.Order
isReady, isValid bool
)
ui.Printf("Waiting for Order to be 'ready' for finalization .")
for i := 9; i >= 0; i-- {
time.Sleep(1 * time.Second)
ui.Printf(".")
ro, err = ac.GetOrder(o.ID)
if err != nil {
return nil, errors.Wrapf(err, "error retrieving order %s", o.ID)
}
if ro.Status == "ready" {
isReady = true
ui.Printf(" done!\n")
break
}
}
if !isReady {
ui.Printf(" Error!\n\n")
return nil, errors.Errorf("Unable to validate order: %+v", ro)
}
ui.Printf("Finalizing Order .")
if err = ac.FinalizeOrder(o.FinalizeURL, csr); err != nil {
return nil, errors.Wrapf(err, "error finalizing order")
}
for i := 9; i >= 0; i-- {
time.Sleep(1 * time.Second)
ui.Printf(".")
fo, err = ac.GetOrder(o.ID)
if err != nil {
return nil, errors.Wrapf(err, "error retrieving order %s", o.ID)
}
if fo.Status == "valid" {
isValid = true
ui.Printf(" done!\n")
break
}
}
if !isValid {
ui.Printf(" Error!\n\n")
return nil, errors.Errorf("Unable to finalize order: %+v", fo)
}
return fo, nil
}
func validateSANsForACME(sans []string) ([]string, error) {
dnsNames, ips, emails, uris := splitSANs(sans)
if len(ips) > 0 || len(emails) > 0 || len(uris) > 0 {
return nil, errors.New("IP Address, Email Address, and URI SANs are not supported for ACME flow")
}
for _, dns := range dnsNames {
if strings.Contains(dns, "*") {
return nil, errors.Errorf("wildcard dnsnames (%s) require dns validation, "+
"which is currently not implemented in this client", dns)
}
}
return dnsNames, nil
}
type acmeFlowOp func(*acmeFlow) error
func withProvisionerName(name string) acmeFlowOp {
return func(af *acmeFlow) error {
af.provisionerName = name
return nil
}
}
func withCSR(csr *x509.CertificateRequest) acmeFlowOp {
return func(af *acmeFlow) error {
af.csr = csr
af.subject = csr.Subject.CommonName
af.sans = csr.DNSNames
return nil
}
}
func withSubjectSANs(sub string, sans []string) acmeFlowOp {
return func(af *acmeFlow) error {
af.subject = sub
af.sans = sans
return nil
}
}
type acmeFlow struct {
ctx *cli.Context
provisionerName string
csr *x509.CertificateRequest
priv interface{}
subject string
sans []string
acmeDir string
}
func newACMEFlow(ctx *cli.Context, ops ...acmeFlowOp) (*acmeFlow, error) {
// Offline mode is not supported for ACME protocol
if ctx.Bool("offline") {
return nil, errors.New("offline mode and ACME are mutually exclusive")
}
// One of --standalone or --webroot must be selected for use with ACME protocol.
isStandalone, webroot := ctx.Bool("standalone"), ctx.String("webroot")
switch {
case isStandalone && len(webroot) > 0:
return nil, errs.MutuallyExclusiveFlags(ctx, "standalone", "webroot")
case !isStandalone && len(webroot) == 0:
if err := ctx.Set("standalone", "true"); err != nil {
return nil, errors.Wrap(err, "error setting 'standalone' value in cli ctx")
}
}
af := new(acmeFlow)
for _, op := range ops {
if err := op(af); err != nil {
return nil, err
}
}
if len(af.sans) == 0 {
af.sans = []string{af.subject}
}
af.ctx = ctx
af.acmeDir = ctx.String("acme")
if len(af.acmeDir) == 0 {
caURL, err := flags.ParseCaURL(ctx)
if err != nil {
return nil, err
}
if len(af.provisionerName) == 0 {
return nil, errors.New("acme flow expected provisioner ID")
}
af.acmeDir = fmt.Sprintf("%s/acme/%s/directory", caURL, af.provisionerName)
}
return af, nil
}
func (af *acmeFlow) GetCertificate() ([]*x509.Certificate, error) {
dnsNames, err := validateSANsForACME(af.sans)
if err != nil {
return nil, err
}
var idents []acme.Identifier
for _, dns := range dnsNames {
idents = append(idents, acme.Identifier{
Type: "dns",
Value: dns,
})
}
var (
orderPayload []byte
clientOps []ca.ClientOption
)
if strings.Contains(af.acmeDir, "letsencrypt") {
// LetsEncrypt does not support NotBefore and NotAfter attributes in orders.
if af.ctx.IsSet("not-before") || af.ctx.IsSet("not-after") {
return nil, errors.New("LetsEncrypt public CA does not support NotBefore/NotAfter " +
"attributes for certificates. Instead, each certificate has a default lifetime of 3 months.")
}
// Use default transport for public CAs
clientOps = append(clientOps, ca.WithTransport(http.DefaultTransport))
// LetsEncrypt requires that the Common Name of the Certificate also be
// represented as a DNSName in the SAN extension, and therefore must be
// authorized as part of the ACME order.
hasSubject := false
for _, n := range idents {
if n.Value == af.subject {
hasSubject = true
}
}
if !hasSubject {
dnsNames = append(dnsNames, af.subject)
idents = append(idents, acme.Identifier{
Type: "dns",
Value: af.subject,
})
}
orderPayload, err = json.Marshal(struct {
Identifiers []acme.Identifier
}{Identifiers: idents})
if err != nil {
return nil, errors.Wrap(err, "error marshaling new letsencrypt order request")
}
} else {
// If the CA is not public then a root file is required.
root := af.ctx.String("root")
if len(root) == 0 {
root = pki.GetRootCAPath()
if _, err := os.Stat(root); err != nil {
return nil, errs.RequiredFlag(af.ctx, "root")
}
}
clientOps = append(clientOps, ca.WithRootFile(root))
// parse times or durations
nbf, naf, err := flags.ParseTimeDuration(af.ctx)
if err != nil {
return nil, err
}
nor := acmeAPI.NewOrderRequest{
Identifiers: idents,
NotAfter: naf.Time(),
NotBefore: nbf.Time(),
}
orderPayload, err = json.Marshal(nor)
if err != nil {
return nil, errors.Wrap(err, "error marshaling new order request")
}
}
ac, err := ca.NewACMEClient(af.acmeDir, af.ctx.StringSlice("contact"), clientOps...)
if err != nil {
return nil, errors.Wrapf(err, "error initializing ACME client with server %s", af.acmeDir)
}
o, err := ac.NewOrder(orderPayload)
if err != nil {
return nil, errors.Wrapf(err, "error creating new ACME order")
}
if err = authorizeOrder(af.ctx, ac, o); err != nil {
return nil, err
}
if af.csr == nil {
insecure := af.ctx.Bool("insecure")
kty, crv, size, err := utils.GetKeyDetailsFromCLI(af.ctx, insecure, "kty", "curve", "size")
if err != nil {
return nil, err
}
af.priv, err = keys.GenerateKey(kty, crv, size)
if err != nil {
return nil, errors.Wrap(err, "error generating private key")
}
_csr := &x509.CertificateRequest{
Subject: pkix.Name{
CommonName: af.subject,
},
DNSNames: dnsNames,
}
var csrBytes []byte
csrBytes, err = x509.CreateCertificateRequest(rand.Reader, _csr, af.priv)
if err != nil {
return nil, errors.Wrap(err, "error creating certificate request")
}
af.csr, err = x509.ParseCertificateRequest(csrBytes)
if err != nil {
return nil, errors.Wrap(err, "error parsing certificate request")
}
}
fo, err := finalizeOrder(ac, o, af.csr)
if err != nil {
return nil, err
}
leaf, chain, err := ac.GetCertificate(fo.CertificateURL)
if err != nil {
return nil, errors.Wrapf(err, "error getting certificate")
}
return append([]*x509.Certificate{leaf}, chain...), nil
}
func writeCert(chain []*x509.Certificate, certFile string) error {
var certBytes = []byte{}
for _, c := range chain {
certBytes = append(certBytes, pem.EncodeToMemory(&pem.Block{
Type: "CERTIFICATE",
Bytes: c.Raw,
})...)
}
if err := utils.WriteFile(certFile, certBytes, 0600); err != nil {
return errs.FileError(err, certFile)
}
return nil
}
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