Add support for multiple SCEP provisioners

Similarly to how ACME suppors multiple provisioners, it's
now possible to load the right provisioner based on the
URL.

ca/ca.go

@@ -174,7 +174,7 @@ func (ca *CA) Init(config *authority.Config) (*CA, error) {
 		scepRouterHandler.Route(r)
 	})
 
-	// helpful routine for logging all routes //
+	// helpful routine for logging all routes
 	//dumpRoutes(mux)
 
 	// Add monitoring if configured

scep/api/api.go

@@ -9,8 +9,10 @@ import (
 	"io"
 	"io/ioutil"
 	"net/http"
+	"net/url"
 	"strings"
 
+	"github.com/go-chi/chi"
 	"github.com/smallstep/certificates/api"
 	"github.com/smallstep/certificates/authority/provisioner"
 	"github.com/smallstep/certificates/scep"
@@ -76,14 +78,10 @@ func New(scepAuth scep.Interface) api.RouterHandler {
 
 // Route traffic and implement the Router interface.
 func (h *Handler) Route(r api.Router) {
-	//getLink := h.Auth.GetLinkExplicit
-	//fmt.Println(getLink)
+	getLink := h.Auth.GetLinkExplicit
 
-	//r.MethodFunc("GET", "/bla", h.baseURLFromRequest(h.lookupProvisioner(nil)))
-	//r.MethodFunc("GET", getLink(acme.NewNonceLink, "{provisionerID}", false, nil), h.baseURLFromRequest(h.lookupProvisioner(h.addNonce(h.GetNonce))))
-
-	r.MethodFunc(http.MethodGet, "/", h.lookupProvisioner(h.Get))
-	r.MethodFunc(http.MethodPost, "/", h.lookupProvisioner(h.Post))
+	r.MethodFunc(http.MethodGet, getLink("{provisionerID}", false, nil), h.lookupProvisioner(h.Get))
+	r.MethodFunc(http.MethodPost, getLink("{provisionerID}", false, nil), h.lookupProvisioner(h.Post))
 
 }
 
@@ -202,16 +200,12 @@ func decodeSCEPRequest(r *http.Request) (SCEPRequest, error) {
 func (h *Handler) lookupProvisioner(next nextHTTP) nextHTTP {
 	return func(w http.ResponseWriter, r *http.Request) {
 
-		// name := chi.URLParam(r, "provisionerID")
-		// provisionerID, err := url.PathUnescape(name)
-		// if err != nil {
-		// 	api.WriteError(w, fmt.Errorf("error url unescaping provisioner id '%s'", name))
-		// 	return
-		// }
-
-		// TODO: make this configurable; and we might want to look at being able to provide multiple,
-		// like the ACME one? The below assumes a SCEP provider (scep/) called "scep1" exists.
-		provisionerID := "scep1"
+		name := chi.URLParam(r, "provisionerID")
+		provisionerID, err := url.PathUnescape(name)
+		if err != nil {
+			api.WriteError(w, fmt.Errorf("error url unescaping provisioner id '%s'", name))
+			return
+		}
 
 		p, err := h.Auth.LoadProvisionerByID("scep/" + provisionerID)
 		if err != nil {
@@ -275,6 +269,8 @@ func (h *Handler) PKIOperation(ctx context.Context, request SCEPRequest) (SCEPRe
 
 	response := SCEPResponse{Operation: opnPKIOperation}
 
+	fmt.Println("BEFORE PARSING")
+
 	microMsg, err := microscep.ParsePKIMessage(request.Message)
 	if err != nil {
 		return SCEPResponse{}, err
@@ -287,7 +283,12 @@ func (h *Handler) PKIOperation(ctx context.Context, request SCEPRequest) (SCEPRe
 		Raw:           microMsg.Raw,
 	}
 
+	fmt.Println("len raw:", len(microMsg.Raw))
+
+	fmt.Println("AFTER PARSING")
+
 	if err := h.Auth.DecryptPKIEnvelope(ctx, msg); err != nil {
+		fmt.Println("ERROR IN DECRYPTPKIENVELOPE")
 		return SCEPResponse{}, err
 	}
 
@@ -311,6 +312,8 @@ func (h *Handler) PKIOperation(ctx context.Context, request SCEPRequest) (SCEPRe
 	response.Data = certRep.Raw
 	response.Certificate = certRep.Certificate
 
+	fmt.Println("HERE!!!")
+
 	return response, nil
 }
 
@@ -336,8 +339,8 @@ func writeSCEPResponse(w http.ResponseWriter, response SCEPResponse) {
 
 func writeError(w http.ResponseWriter, err error) {
 	scepError := &scep.Error{
-		Err:    fmt.Errorf("post request failed: %w", err),
-		Status: http.StatusInternalServerError, // TODO: make this a param?
+		Message: err.Error(),
+		Status:  http.StatusInternalServerError, // TODO: make this a param?
 	}
 	api.WriteError(w, scepError)
 }

scep/authority.go

@@ -8,6 +8,7 @@ import (
 	"crypto/x509"
 	"errors"
 	"fmt"
+	"net/url"
 
 	"github.com/smallstep/certificates/authority/provisioner"
 	database "github.com/smallstep/certificates/db"
@@ -55,6 +56,8 @@ type Interface interface {
 	GetCACertificates() ([]*x509.Certificate, error)
 	DecryptPKIEnvelope(ctx context.Context, msg *PKIMessage) error
 	SignCSR(ctx context.Context, csr *x509.CertificateRequest, msg *PKIMessage) (*PKIMessage, error)
+
+	GetLinkExplicit(provName string, absoluteLink bool, baseURL *url.URL, inputs ...string) string
 }
 
 // Authority is the layer that handles all SCEP interactions.
@@ -130,6 +133,44 @@ func (a *Authority) LoadProvisionerByID(id string) (provisioner.Interface, error
 	return a.signAuth.LoadProvisionerByID(id)
 }
 
+// GetLinkExplicit returns the requested link from the directory.
+func (a *Authority) GetLinkExplicit(provName string, abs bool, baseURL *url.URL, inputs ...string) string {
+	// TODO: taken from ACME; move it to directory (if we need a directory in SCEP)?
+	return a.getLinkExplicit(provName, abs, baseURL, inputs...)
+}
+
+// getLinkExplicit returns an absolute or partial path to the given resource and a base
+// URL dynamically obtained from the request for which the link is being calculated.
+func (a *Authority) getLinkExplicit(provisionerName string, abs bool, baseURL *url.URL, inputs ...string) string {
+
+	// TODO: do we need to provide a way to provide a different suffix/base?
+	// Like "/cgi-bin/pkiclient.exe"? Or would it be enough to have that as the name?
+	link := fmt.Sprintf("/%s", provisionerName)
+
+	if abs {
+		// Copy the baseURL value from the pointer. https://github.com/golang/go/issues/38351
+		u := url.URL{}
+		if baseURL != nil {
+			u = *baseURL
+		}
+
+		// If no Scheme is set, then default to https.
+		if u.Scheme == "" {
+			u.Scheme = "https"
+		}
+
+		// If no Host is set, then use the default (first DNS attr in the ca.json).
+		if u.Host == "" {
+			u.Host = a.dns
+		}
+
+		u.Path = a.prefix + link
+		return u.String()
+	}
+
+	return link
+}
+
 // GetCACertificates returns the certificate (chain) for the CA
 func (a *Authority) GetCACertificates() ([]*x509.Certificate, error) {
 
@@ -164,6 +205,8 @@ func (a *Authority) DecryptPKIEnvelope(ctx context.Context, msg *PKIMessage) err
 		return err
 	}
 
+	fmt.Println("len content:", len(p7.Content))
+
 	var tID microscep.TransactionID
 	if err := p7.UnmarshalSignedAttribute(oidSCEPtransactionID, &tID); err != nil {
 		return err
@@ -176,11 +219,17 @@ func (a *Authority) DecryptPKIEnvelope(ctx context.Context, msg *PKIMessage) err
 
 	msg.p7 = p7
 
+	//p7c, err := pkcs7.Parse(p7.Content)
 	p7c, err := pkcs7.Parse(p7.Content)
 	if err != nil {
 		return err
 	}
 
+	fmt.Println(tID)
+	fmt.Println(msgType)
+
+	fmt.Println("len p7c content:", len(p7c.Content))
+
 	envelope, err := p7c.Decrypt(a.intermediateCertificate, a.service.Decrypter)
 	if err != nil {
 		return err
@@ -308,7 +357,7 @@ func (a *Authority) SignCSR(ctx context.Context, csr *x509.CertificateRequest, m
 	// fmt.Println(string(cert.SubjectKeyId))
 
 	// create a degenerate cert structure
-	deg, err := DegenerateCertificates([]*x509.Certificate{cert})
+	deg, err := degenerateCertificates([]*x509.Certificate{cert})
 	if err != nil {
 		return nil, err
 	}
@@ -380,8 +429,8 @@ func (a *Authority) SignCSR(ctx context.Context, csr *x509.CertificateRequest, m
 	return crepMsg, nil
 }
 
-// DegenerateCertificates creates degenerate certificates pkcs#7 type
-func DegenerateCertificates(certs []*x509.Certificate) ([]byte, error) {
+// degenerateCertificates creates degenerate certificates pkcs#7 type
+func degenerateCertificates(certs []*x509.Certificate) ([]byte, error) {
 	var buf bytes.Buffer
 	for _, cert := range certs {
 		buf.Write(cert.Raw)

scep/errors.go

@@ -4,8 +4,8 @@ package scep
 type Error struct {
 	// Type       ProbType
 	// Detail string
-	Err    error
-	Status int
+	Message string `json:"message"`
+	Status  int    `json:"-"`
 	// Sub    []*Error
 	// Identifier *Identifier
 }
@@ -15,5 +15,5 @@ func (e *Error) Error() string {
 	// if e.Err == nil {
 	// 	return e.Detail
 	// }
-	return e.Err.Error()
+	return e.Message
 }