certificates/acme/api/handler.go
2020-04-30 04:44:08 -07:00

215 lines
7.5 KiB
Go

package api
import (
"fmt"
"github.com/go-chi/chi"
"github.com/pkg/errors"
"github.com/smallstep/certificates/acme"
"github.com/smallstep/certificates/api"
"github.com/smallstep/certificates/authority/provisioner"
"github.com/smallstep/cli/jose"
"net/http"
)
func link(url, typ string) string {
return fmt.Sprintf("<%s>;rel=\"%s\"", url, typ)
}
type contextKey string
const (
accContextKey = contextKey("acc")
jwsContextKey = contextKey("jws")
jwkContextKey = contextKey("jwk")
payloadContextKey = contextKey("payload")
provisionerContextKey = contextKey("provisioner")
)
type payloadInfo struct {
value []byte
isPostAsGet bool
isEmptyJSON bool
}
func accountFromContext(r *http.Request) (*acme.Account, error) {
val, ok := r.Context().Value(accContextKey).(*acme.Account)
if !ok || val == nil {
return nil, acme.AccountDoesNotExistErr(nil)
}
return val, nil
}
func jwkFromContext(r *http.Request) (*jose.JSONWebKey, error) {
val, ok := r.Context().Value(jwkContextKey).(*jose.JSONWebKey)
if !ok || val == nil {
return nil, acme.ServerInternalErr(errors.Errorf("jwk expected in request context"))
}
return val, nil
}
func jwsFromContext(r *http.Request) (*jose.JSONWebSignature, error) {
val, ok := r.Context().Value(jwsContextKey).(*jose.JSONWebSignature)
if !ok || val == nil {
return nil, acme.ServerInternalErr(errors.Errorf("jws expected in request context"))
}
return val, nil
}
func payloadFromContext(r *http.Request) (*payloadInfo, error) {
val, ok := r.Context().Value(payloadContextKey).(*payloadInfo)
if !ok || val == nil {
return nil, acme.ServerInternalErr(errors.Errorf("payload expected in request context"))
}
return val, nil
}
func provisionerFromContext(r *http.Request) (provisioner.Interface, error) {
val, ok := r.Context().Value(provisionerContextKey).(provisioner.Interface)
if !ok || val == nil {
return nil, acme.ServerInternalErr(errors.Errorf("provisioner expected in request context"))
}
return val, nil
}
// New returns a new ACME API router.
func New(acmeAuth acme.Interface) api.RouterHandler {
return &Handler{acmeAuth}
}
// Handler is the ACME request handler.
type Handler struct {
Auth acme.Interface
}
// Route traffic and implement the Router interface.
func (h *Handler) Route(r api.Router) {
getLink := h.Auth.GetLink
// Standard ACME API
r.MethodFunc("GET", getLink(acme.NewNonceLink, "{provisionerID}", false), h.lookupProvisioner(h.addNonce(h.GetNonce)))
r.MethodFunc("HEAD", getLink(acme.NewNonceLink, "{provisionerID}", false), h.lookupProvisioner(h.addNonce(h.GetNonce)))
r.MethodFunc("GET", getLink(acme.DirectoryLink, "{provisionerID}", false), h.lookupProvisioner(h.addNonce(h.GetDirectory)))
r.MethodFunc("HEAD", getLink(acme.DirectoryLink, "{provisionerID}", false), h.lookupProvisioner(h.addNonce(h.GetDirectory)))
extractPayloadByJWK := func(next nextHTTP) nextHTTP {
return h.lookupProvisioner(h.addNonce(h.addDirLink(h.verifyContentType(h.parseJWS(h.validateJWS(h.extractJWK(h.verifyAndExtractJWSPayload(next))))))))
}
extractPayloadByKid := func(next nextHTTP) nextHTTP {
return h.lookupProvisioner(h.addNonce(h.addDirLink(h.verifyContentType(h.parseJWS(h.validateJWS(h.lookupJWK(h.verifyAndExtractJWSPayload(next))))))))
}
r.MethodFunc("POST", getLink(acme.NewAccountLink, "{provisionerID}", false), extractPayloadByJWK(h.NewAccount))
r.MethodFunc("POST", getLink(acme.AccountLink, "{provisionerID}", false, "{accID}"), extractPayloadByKid(h.GetUpdateAccount))
r.MethodFunc("POST", getLink(acme.NewOrderLink, "{provisionerID}", false), extractPayloadByKid(h.NewOrder))
r.MethodFunc("POST", getLink(acme.OrderLink, "{provisionerID}", false, "{ordID}"), extractPayloadByKid(h.isPostAsGet(h.GetOrder)))
r.MethodFunc("POST", getLink(acme.OrdersByAccountLink, "{provisionerID}", false, "{accID}"), extractPayloadByKid(h.isPostAsGet(h.GetOrdersByAccount)))
r.MethodFunc("POST", getLink(acme.FinalizeLink, "{provisionerID}", false, "{ordID}"), extractPayloadByKid(h.FinalizeOrder))
r.MethodFunc("POST", getLink(acme.AuthzLink, "{provisionerID}", false, "{authzID}"), extractPayloadByKid(h.isPostAsGet(h.GetAuthz)))
r.MethodFunc("POST", getLink(acme.ChallengeLink, "{provisionerID}", false, "{chID}"), extractPayloadByKid(h.GetChallenge))
r.MethodFunc("POST", getLink(acme.CertificateLink, "{provisionerID}", false, "{certID}"), extractPayloadByKid(h.isPostAsGet(h.GetCertificate)))
}
// GetNonce just sets the right header since a Nonce is added to each response
// by middleware by default.
func (h *Handler) GetNonce(w http.ResponseWriter, r *http.Request) {
if r.Method == "HEAD" {
w.WriteHeader(http.StatusOK)
} else {
w.WriteHeader(http.StatusNoContent)
}
}
// GetDirectory is the ACME resource for returning a directory configuration
// for client configuration.
func (h *Handler) GetDirectory(w http.ResponseWriter, r *http.Request) {
prov, err := provisionerFromContext(r)
if err != nil {
api.WriteError(w, err)
return
}
dir := h.Auth.GetDirectory(prov)
api.JSON(w, dir)
}
// GetAuthz ACME api for retrieving an Authz.
func (h *Handler) GetAuthz(w http.ResponseWriter, r *http.Request) {
prov, err := provisionerFromContext(r)
if err != nil {
api.WriteError(w, err)
return
}
acc, err := accountFromContext(r)
if err != nil {
api.WriteError(w, err)
return
}
authz, err := h.Auth.GetAuthz(prov, acc.GetID(), chi.URLParam(r, "authzID"))
if err != nil {
api.WriteError(w, err)
return
}
w.Header().Set("Location", h.Auth.GetLink(acme.AuthzLink, acme.URLSafeProvisionerName(prov), true, authz.GetID()))
api.JSON(w, authz)
}
// GetChallenge ACME api for retrieving a Challenge.
func (h *Handler) GetChallenge(w http.ResponseWriter, r *http.Request) {
prov, err := provisionerFromContext(r)
if err != nil {
api.WriteError(w, err)
return
}
acc, err := accountFromContext(r)
if err != nil {
api.WriteError(w, err)
return
}
// Just verify that the payload was set, since we're not strictly adhering
// to ACME V2 spec for reasons specified below.
_, err = payloadFromContext(r)
if err != nil {
api.WriteError(w, err)
return
}
// NOTE: We should be checking that the request is either a POST-as-GET, or
// that the payload is an empty JSON block ({}). However, older ACME clients
// still send a vestigial body (rather than an empty JSON block) and
// strict enforcement would render these clients broken. For the time being
// we'll just ignore the body.
var (
ch *acme.Challenge
chID = chi.URLParam(r, "chID")
)
ch, err = h.Auth.ValidateChallenge(prov, acc.GetID(), chID, acc.GetKey())
if err != nil {
api.WriteError(w, err)
} else if ch.Retry.Active {
retryAfter, err := h.Auth.BackoffChallenge(prov, acc.GetID(), chID, acc.GetKey())
if err != nil {
api.WriteError(w, err)
} else {
w.Header().Add("Retry-After", retryAfter.String())
api.WriteProcessing(w, ch)
}
} else {
getLink := h.Auth.GetLink
w.Header().Add("Link", link(getLink(acme.AuthzLink, acme.URLSafeProvisionerName(prov), true, ch.GetAuthzID()), "up"))
w.Header().Set("Location", getLink(acme.ChallengeLink, acme.URLSafeProvisionerName(prov), true, ch.GetID()))
api.JSON(w, ch)
}
}
// GetCertificate ACME api for retrieving a Certificate.
func (h *Handler) GetCertificate(w http.ResponseWriter, r *http.Request) {
acc, err := accountFromContext(r)
if err != nil {
api.WriteError(w, err)
return
}
certID := chi.URLParam(r, "certID")
certBytes, err := h.Auth.GetCertificate(acc.GetID(), certID)
if err != nil {
api.WriteError(w, err)
return
}
w.Header().Set("Content-Type", "application/pem-certificate-chain; charset=utf-8")
w.Write(certBytes)
}