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Remove x509 template from API
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hslatman committed Feb 26, 2021
1 parent 311c9d7 commit a6d50f2
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Showing 2 changed files with 56 additions and 56 deletions.
64 changes: 11 additions & 53 deletions scep/api/api.go
Original file line number Diff line number Diff line change
Expand Up @@ -2,19 +2,14 @@ package api

import (
"context"
"crypto"
"crypto/sha1"
"crypto/x509"
"encoding/base64"
"errors"
"fmt"
"io"
"io/ioutil"
"math/big"
"math/rand"
"net/http"
"strings"
"time"

"github.com/smallstep/certificates/acme"
"github.com/smallstep/certificates/api"
Expand Down Expand Up @@ -252,53 +247,29 @@ func (h *Handler) PKIOperation(w http.ResponseWriter, r *http.Request, scepReque

ctx := r.Context()

msg, err := microscep.ParsePKIMessage(scepRequest.Message)
microMsg, err := microscep.ParsePKIMessage(scepRequest.Message)
if err != nil {
return err
}

pkimsg := &scep.PKIMessage{
TransactionID: msg.TransactionID,
MessageType: msg.MessageType,
SenderNonce: msg.SenderNonce,
Raw: msg.Raw,
msg := &scep.PKIMessage{
TransactionID: microMsg.TransactionID,
MessageType: microMsg.MessageType,
SenderNonce: microMsg.SenderNonce,
Raw: microMsg.Raw,
}

if err := h.Auth.DecryptPKIEnvelope(ctx, pkimsg); err != nil {
if err := h.Auth.DecryptPKIEnvelope(ctx, msg); err != nil {
return err
}

if pkimsg.MessageType == microscep.PKCSReq {
if msg.MessageType == microscep.PKCSReq {
// TODO: CSR validation, like challenge password
}

csr := pkimsg.CSRReqMessage.CSR
subjectKeyID, err := createKeyIdentifier(csr.PublicKey)
if err != nil {
return err
}
csr := msg.CSRReqMessage.CSR

serial := big.NewInt(int64(rand.Int63())) // TODO: serial logic?

days := 40

// TODO: use information from provisioner, like claims
template := &x509.Certificate{
SerialNumber: serial,
Subject: csr.Subject,
NotBefore: time.Now().Add(-600).UTC(),
NotAfter: time.Now().AddDate(0, 0, days).UTC(),
SubjectKeyId: subjectKeyID,
KeyUsage: x509.KeyUsageDigitalSignature,
ExtKeyUsage: []x509.ExtKeyUsage{
x509.ExtKeyUsageClientAuth,
},
SignatureAlgorithm: csr.SignatureAlgorithm,
EmailAddresses: csr.EmailAddresses,
DNSNames: csr.DNSNames,
}

certRep, err := h.Auth.SignCSR(ctx, pkimsg, template)
certRep, err := h.Auth.SignCSR(ctx, csr, msg)
if err != nil {
return err
}
Expand All @@ -323,20 +294,6 @@ func certName(cert *x509.Certificate) string {
return string(cert.Signature)
}

// createKeyIdentifier creates an identifier for public keys
// according to the first method in RFC5280 section 4.2.1.2.
func createKeyIdentifier(pub crypto.PublicKey) ([]byte, error) {

keyBytes, err := x509.MarshalPKIXPublicKey(pub)
if err != nil {
return nil, err
}

id := sha1.Sum(keyBytes)

return id[:], nil
}

func formatCapabilities(caps []string) []byte {
return []byte(strings.Join(caps, "\r\n"))
}
Expand All @@ -354,6 +311,7 @@ func writeSCEPResponse(w http.ResponseWriter, response SCEPResponse) error {

var (
// TODO: check the default capabilities; https://tools.ietf.org/html/rfc8894#section-3.5.2
// TODO: move capabilities to Authority or Provisioner, so that they can be configured?
defaultCapabilities = []string{
"Renewal",
"SHA-1",
Expand Down
48 changes: 45 additions & 3 deletions scep/authority.go
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,8 @@ package scep
import (
"bytes"
"context"
"crypto"
"crypto/sha1"
"crypto/x509"
"errors"
"fmt"
Expand Down Expand Up @@ -52,7 +54,7 @@ type Interface interface {

GetCACertificates() ([]*x509.Certificate, error)
DecryptPKIEnvelope(ctx context.Context, msg *PKIMessage) error
SignCSR(ctx context.Context, msg *PKIMessage, template *x509.Certificate) (*PKIMessage, error)
SignCSR(ctx context.Context, csr *x509.CertificateRequest, msg *PKIMessage) (*PKIMessage, error)
}

// Authority is the layer that handles all SCEP interactions.
Expand Down Expand Up @@ -221,7 +223,8 @@ func (a *Authority) DecryptPKIEnvelope(ctx context.Context, msg *PKIMessage) err
// SignCSR creates an x509.Certificate based on a CSR template and Cert Authority credentials
// returns a new PKIMessage with CertRep data
//func (msg *PKIMessage) SignCSR(crtAuth *x509.Certificate, keyAuth *rsa.PrivateKey, template *x509.Certificate) (*PKIMessage, error) {
func (a *Authority) SignCSR(ctx context.Context, msg *PKIMessage, template *x509.Certificate) (*PKIMessage, error) {
//func (a *Authority) SignCSR(ctx context.Context, msg *PKIMessage, template *x509.Certificate) (*PKIMessage, error) {
func (a *Authority) SignCSR(ctx context.Context, csr *x509.CertificateRequest, msg *PKIMessage) (*PKIMessage, error) {

// TODO: intermediate storage of the request? In SCEP it's possible to request a csr/certificate
// to be signed, which can be performed asynchronously / out-of-band. In that case a client can
Expand All @@ -238,9 +241,32 @@ func (a *Authority) SignCSR(ctx context.Context, msg *PKIMessage, template *x509
if err := a.DecryptPKIEnvelope(ctx, msg); err != nil {
return nil, err
}
csr = msg.CSRReqMessage.CSR
}

csr := msg.CSRReqMessage.CSR
// subjectKeyID, err := createKeyIdentifier(csr.PublicKey)
// if err != nil {
// return nil, err
// }

// serial := big.NewInt(int64(rand.Int63())) // TODO: serial logic?
// days := 40 // TODO: days

// // TODO: use information from provisioner, like claims
// template := &x509.Certificate{
// SerialNumber: serial,
// Subject: csr.Subject,
// NotBefore: time.Now().Add(-600).UTC(),
// NotAfter: time.Now().AddDate(0, 0, days).UTC(),
// SubjectKeyId: subjectKeyID,
// KeyUsage: x509.KeyUsageDigitalSignature,
// ExtKeyUsage: []x509.ExtKeyUsage{
// x509.ExtKeyUsageClientAuth,
// },
// SignatureAlgorithm: csr.SignatureAlgorithm,
// EmailAddresses: csr.EmailAddresses,
// DNSNames: csr.DNSNames,
// }

// Template data
data := x509util.NewTemplateData()
Expand Down Expand Up @@ -278,6 +304,8 @@ func (a *Authority) SignCSR(ctx context.Context, msg *PKIMessage, template *x509
// fmt.Println(fmt.Sprintf("%T", cert))
// fmt.Println(cert.Issuer)
// fmt.Println(cert.Subject)
// fmt.Println(cert.SerialNumber)
// fmt.Println(string(cert.SubjectKeyId))

// create a degenerate cert structure
deg, err := DegenerateCertificates([]*x509.Certificate{cert})
Expand Down Expand Up @@ -365,6 +393,20 @@ func DegenerateCertificates(certs []*x509.Certificate) ([]byte, error) {
return degenerate, nil
}

// createKeyIdentifier creates an identifier for public keys
// according to the first method in RFC5280 section 4.2.1.2.
func createKeyIdentifier(pub crypto.PublicKey) ([]byte, error) {

keyBytes, err := x509.MarshalPKIXPublicKey(pub)
if err != nil {
return nil, err
}

id := sha1.Sum(keyBytes)

return id[:], nil
}

// Interface guards
var (
_ Interface = (*Authority)(nil)
Expand Down

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