Add first working version of External Account Binding

acme/account.go

@@ -4,6 +4,7 @@ import (
 	"crypto"
 	"encoding/base64"
 	"encoding/json"
+	"time"
 
 	"go.step.sm/crypto/jose"
 )
@@ -40,3 +41,12 @@ func KeyToID(jwk *jose.JSONWebKey) (string, error) {
 	}
 	return base64.RawURLEncoding.EncodeToString(kid), nil
 }
+
+type ExternalAccountKey struct {
+	ID        string    `json:"id"`
+	Name      string    `json:"name"`
+	AccountID string    `json:"-"`
+	KeyBytes  []byte    `json:"-"`
+	CreatedAt time.Time `json:"createdAt"`
+	BoundAt   time.Time `json:"boundAt,omitempty"`
+}

acme/api/account.go

@@ -1,13 +1,18 @@
 package api
 
 import (
+	"bytes"
+	"context"
 	"encoding/json"
 	"net/http"
 
 	"github.com/go-chi/chi"
 	"github.com/smallstep/certificates/acme"
 	"github.com/smallstep/certificates/api"
+	"github.com/smallstep/certificates/authority/provisioner"
 	"github.com/smallstep/certificates/logging"
+
+	squarejose "gopkg.in/square/go-jose.v2"
 )
 
 // NewAccountRequest represents the payload for a new account request.
@@ -15,6 +20,7 @@ type NewAccountRequest struct {
 	Contact                []string    `json:"contact"`
 	OnlyReturnExisting     bool        `json:"onlyReturnExisting"`
 	TermsOfServiceAgreed   bool        `json:"termsOfServiceAgreed"`
+	ExternalAccountBinding interface{} `json:"externalAccountBinding,omitempty"`
 }
 
 func validateContacts(cs []string) error {
@@ -83,6 +89,14 @@ func (h *Handler) NewAccount(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if err := h.validateExternalAccountBinding(ctx, &nar); err != nil {
+		api.WriteError(w, err)
+		return
+	}
+
+	// TODO: link account to the key when created; mark boundat timestamp
+	// TODO: return the externalAccountBinding field (should contain same info) if new account created
+
 	httpStatus := http.StatusCreated
 	acc, err := accountFromContext(r.Context())
 	if err != nil {
@@ -205,3 +219,66 @@ func (h *Handler) GetOrdersByAccountID(w http.ResponseWriter, r *http.Request) {
 	api.JSON(w, orders)
 	logOrdersByAccount(w, orders)
 }
+
+// validateExternalAccountBinding validates the externalAccountBinding property in a call to new-account
+func (h *Handler) validateExternalAccountBinding(ctx context.Context, nar *NewAccountRequest) error {
+
+	prov, err := provisionerFromContext(ctx)
+	if err != nil {
+		return err
+	}
+
+	acmeProv, ok := prov.(*provisioner.ACME) // TODO: rewrite into providing configuration via function on acme.Provisioner
+	if !ok || acmeProv == nil {
+		return acme.NewErrorISE("provisioner in context is not an ACME provisioner")
+	}
+
+	shouldSkipAccountBindingValidation := !acmeProv.RequireEAB
+	if shouldSkipAccountBindingValidation {
+		return nil
+	}
+
+	if nar.ExternalAccountBinding == nil {
+		return acme.NewError(acme.ErrorExternalAccountRequiredType, "no external account binding provided")
+	}
+
+	eabJSONBytes, err := json.Marshal(nar.ExternalAccountBinding)
+	if err != nil {
+		return acme.WrapErrorISE(err, "error marshalling externalAccountBinding")
+	}
+
+	eabJWS, err := squarejose.ParseSigned(string(eabJSONBytes))
+	if err != nil {
+		return acme.WrapErrorISE(err, "error parsing externalAccountBinding jws")
+	}
+
+	// TODO: verify supported algorithms against the incoming alg (and corresponding settings)?
+	// TODO: implement strategy pattern to allow for different ways of verification (i.e. webhook call) based on configuration
+
+	keyID := eabJWS.Signatures[0].Protected.KeyID
+	externalAccountKey, err := h.db.GetExternalAccountKey(ctx, keyID)
+	if err != nil {
+		return acme.WrapErrorISE(err, "error retrieving external account key")
+	}
+
+	payload, err := eabJWS.Verify(externalAccountKey.KeyBytes)
+	if err != nil {
+		return acme.WrapErrorISE(err, "error verifying externalAccountBinding signature")
+	}
+
+	jwk, err := jwkFromContext(ctx)
+	if err != nil {
+		return err
+	}
+
+	jwkJSONBytes, err := jwk.MarshalJSON()
+	if err != nil {
+		return acme.WrapErrorISE(err, "error marshaling jwk")
+	}
+
+	if bytes.Equal(payload, jwkJSONBytes) {
+		acme.NewError(acme.ErrorMalformedType, "keys in jws and eab payload do not match") // TODO: decide ACME error type to use
+	}
+
+	return nil
+}

acme/api/handler.go

@@ -123,6 +123,13 @@ func (h *Handler) GetNonce(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+type Meta struct {
+	TermsOfService          string   `json:"termsOfService,omitempty"`
+	Website                 string   `json:"website,omitempty"`
+	CaaIdentities           []string `json:"caaIdentities,omitempty"`
+	ExternalAccountRequired bool     `json:"externalAccountRequired,omitempty"`
+}
+
 // Directory represents an ACME directory for configuring clients.
 type Directory struct {
 	NewNonce   string `json:"newNonce"`
@@ -130,6 +137,7 @@ type Directory struct {
 	NewOrder   string `json:"newOrder"`
 	RevokeCert string `json:"revokeCert"`
 	KeyChange  string `json:"keyChange"`
+	Meta       Meta   `json:"meta"`
 }
 
 // ToLog enables response logging for the Directory type.
@@ -145,12 +153,27 @@ func (d *Directory) ToLog() (interface{}, error) {
 // for client configuration.
 func (h *Handler) GetDirectory(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
+	prov, err := provisionerFromContext(ctx)
+	if err != nil {
+		api.WriteError(w, err)
+		return
+	}
+
+	acmeProv, ok := prov.(*provisioner.ACME) // TODO: rewrite into providing configuration via function on acme.Provisioner
+	if !ok || acmeProv == nil {
+		api.WriteError(w, acme.NewErrorISE("provisioner in context is not an ACME provisioner"))
+		return
+	}
+
 	api.JSON(w, &Directory{
 		NewNonce:   h.linker.GetLink(ctx, NewNonceLinkType),
 		NewAccount: h.linker.GetLink(ctx, NewAccountLinkType),
 		NewOrder:   h.linker.GetLink(ctx, NewOrderLinkType),
 		RevokeCert: h.linker.GetLink(ctx, RevokeCertLinkType),
 		KeyChange:  h.linker.GetLink(ctx, KeyChangeLinkType),
+		Meta: Meta{
+			ExternalAccountRequired: acmeProv.RequireEAB,
+		},
 	})
 }
 

acme/db.go

@@ -19,6 +19,9 @@ type DB interface {
 	GetAccountByKeyID(ctx context.Context, kid string) (*Account, error)
 	UpdateAccount(ctx context.Context, acc *Account) error
 
+	CreateExternalAccountKey(ctx context.Context, name string) (*ExternalAccountKey, error)
+	GetExternalAccountKey(ctx context.Context, keyID string) (*ExternalAccountKey, error)
+
 	CreateNonce(ctx context.Context) (Nonce, error)
 	DeleteNonce(ctx context.Context, nonce Nonce) error
 
@@ -47,6 +50,9 @@ type MockDB struct {
 	MockGetAccountByKeyID func(ctx context.Context, kid string) (*Account, error)
 	MockUpdateAccount     func(ctx context.Context, acc *Account) error
 
+	MockCreateExternalAccountKey func(ctx context.Context, name string) (*ExternalAccountKey, error)
+	MockGetExternalAccountKey    func(ctx context.Context, keyID string) (*ExternalAccountKey, error)
+
 	MockCreateNonce func(ctx context.Context) (Nonce, error)
 	MockDeleteNonce func(ctx context.Context, nonce Nonce) error
 
@@ -110,6 +116,26 @@ func (m *MockDB) UpdateAccount(ctx context.Context, acc *Account) error {
 	return m.MockError
 }
 
+// CreateExternalAccountKey mock
+func (m *MockDB) CreateExternalAccountKey(ctx context.Context, name string) (*ExternalAccountKey, error) {
+	if m.MockCreateExternalAccountKey != nil {
+		return m.MockCreateExternalAccountKey(ctx, name)
+	} else if m.MockError != nil {
+		return nil, m.MockError
+	}
+	return m.MockRet1.(*ExternalAccountKey), m.MockError
+}
+
+// GetExternalAccountKey mock
+func (m *MockDB) GetExternalAccountKey(ctx context.Context, keyID string) (*ExternalAccountKey, error) {
+	if m.MockGetExternalAccountKey != nil {
+		return m.MockGetExternalAccountKey(ctx, keyID)
+	} else if m.MockError != nil {
+		return nil, m.MockError
+	}
+	return m.MockRet1.(*ExternalAccountKey), m.MockError
+}
+
 // CreateNonce mock
 func (m *MockDB) CreateNonce(ctx context.Context) (Nonce, error) {
 	if m.MockCreateNonce != nil {

acme/db/nosql/account.go

@@ -2,6 +2,7 @@ package nosql
 
 import (
 	"context"
+	"crypto/rand"
 	"encoding/json"
 	"time"
 
@@ -26,6 +27,15 @@ func (dba *dbAccount) clone() *dbAccount {
 	return &nu
 }
 
+type dbExternalAccountKey struct {
+	ID        string    `json:"id"`
+	Name      string    `json:"name"`
+	AccountID string    `json:"accountID,omitempty"`
+	KeyBytes  []byte    `json:"key,omitempty"`
+	CreatedAt time.Time `json:"createdAt"`
+	BoundAt   time.Time `json:"boundAt"`
+}
+
 func (db *DB) getAccountIDByKeyID(ctx context.Context, kid string) (string, error) {
 	id, err := db.db.Get(accountByKeyIDTable, []byte(kid))
 	if err != nil {
@@ -134,3 +144,61 @@ func (db *DB) UpdateAccount(ctx context.Context, acc *acme.Account) error {
 
 	return db.save(ctx, old.ID, nu, old, "account", accountTable)
 }
+
+// CreateExternalAccountKey creates a new External Account Binding key with a name
+func (db *DB) CreateExternalAccountKey(ctx context.Context, name string) (*acme.ExternalAccountKey, error) {
+	keyID, err := randID()
+	if err != nil {
+		return nil, err
+	}
+
+	random := make([]byte, 32)
+	_, err = rand.Read(random)
+	if err != nil {
+		return nil, err
+	}
+
+	dbeak := &dbExternalAccountKey{
+		ID:        keyID,
+		Name:      name,
+		KeyBytes:  random,
+		CreatedAt: clock.Now(),
+	}
+
+	if err = db.save(ctx, keyID, dbeak, nil, "external_account_key", externalAccountKeyTable); err != nil {
+		return nil, err
+	}
+	return &acme.ExternalAccountKey{
+		ID:        dbeak.ID,
+		Name:      dbeak.Name,
+		AccountID: dbeak.AccountID,
+		KeyBytes:  dbeak.KeyBytes,
+		CreatedAt: dbeak.CreatedAt,
+		BoundAt:   dbeak.BoundAt,
+	}, nil
+}
+
+// GetExternalAccountKey retrieves an External Account Binding key by KeyID
+func (db *DB) GetExternalAccountKey(ctx context.Context, keyID string) (*acme.ExternalAccountKey, error) {
+	data, err := db.db.Get(externalAccountKeyTable, []byte(keyID))
+	if err != nil {
+		if nosqlDB.IsErrNotFound(err) {
+			return nil, acme.ErrNotFound
+		}
+		return nil, errors.Wrapf(err, "error loading external account key %s", keyID)
+	}
+
+	dbeak := new(dbExternalAccountKey)
+	if err = json.Unmarshal(data, dbeak); err != nil {
+		return nil, errors.Wrapf(err, "error unmarshaling external account key %s into dbExternalAccountKey", keyID)
+	}
+
+	return &acme.ExternalAccountKey{
+		ID:        dbeak.ID,
+		Name:      dbeak.Name,
+		AccountID: dbeak.AccountID,
+		KeyBytes:  dbeak.KeyBytes,
+		CreatedAt: dbeak.CreatedAt,
+		BoundAt:   dbeak.BoundAt,
+	}, nil
+}

acme/db/nosql/nosql.go

@@ -19,6 +19,7 @@ var (
 	orderTable              = []byte("acme_orders")
 	ordersByAccountIDTable  = []byte("acme_account_orders_index")
 	certTable               = []byte("acme_certs")
+	externalAccountKeyTable = []byte("acme_external_account_keys")
 )
 
 // DB is a struct that implements the AcmeDB interface.
@@ -29,7 +30,7 @@ type DB struct {
 // New configures and returns a new ACME DB backend implemented using a nosql DB.
 func New(db nosqlDB.DB) (*DB, error) {
 	tables := [][]byte{accountTable, accountByKeyIDTable, authzTable,
-		challengeTable, nonceTable, orderTable, ordersByAccountIDTable, certTable}
+		challengeTable, nonceTable, orderTable, ordersByAccountIDTable, certTable, externalAccountKeyTable}
 	for _, b := range tables {
 		if err := db.CreateTable(b); err != nil {
 			return nil, errors.Wrapf(err, "error creating table %s",

authority/admin/api/eak.go

@@ -0,0 +1,45 @@
+package api
+
+import (
+	"net/http"
+
+	"github.com/smallstep/certificates/api"
+	"github.com/smallstep/certificates/authority/admin"
+)
+
+// CreateExternalAccountKeyRequest is the type for GET /admin/eak requests
+type CreateExternalAccountKeyRequest struct {
+	Name string `json:"name"`
+}
+
+// CreateExternalAccountKeyResponse is the type for GET /admin/eak responses
+type CreateExternalAccountKeyResponse struct {
+	KeyID string `json:"keyID"`
+	Name  string `json:"name"`
+	Key   []byte `json:"key"`
+}
+
+// CreateExternalAccountKey creates a new External Account Binding key
+func (h *Handler) CreateExternalAccountKey(w http.ResponseWriter, r *http.Request) {
+	var eakRequest = new(CreateExternalAccountKeyRequest)
+	if err := api.ReadJSON(r.Body, eakRequest); err != nil { // TODO: rewrite into protobuf json (likely)
+		api.WriteError(w, err)
+		return
+	}
+
+	// TODO: Validate input
+
+	eak, err := h.db.CreateExternalAccountKey(r.Context(), eakRequest.Name)
+	if err != nil {
+		api.WriteError(w, admin.WrapErrorISE(err, "error creating external account key %s", eakRequest.Name))
+		return
+	}
+
+	eakResponse := CreateExternalAccountKeyResponse{
+		KeyID: eak.ID,
+		Name:  eak.Name,
+		Key:   eak.KeyBytes,
+	}
+
+	api.JSONStatus(w, eakResponse, http.StatusCreated) // TODO: rewrite into protobuf json (likely)
+}

authority/admin/api/handler.go

@@ -38,4 +38,7 @@ func (h *Handler) Route(r api.Router) {
 	r.MethodFunc("POST", "/admins", authnz(h.CreateAdmin))
 	r.MethodFunc("PATCH", "/admins/{id}", authnz(h.UpdateAdmin))
 	r.MethodFunc("DELETE", "/admins/{id}", authnz(h.DeleteAdmin))
+
+	// External Account Binding Keys
+	r.MethodFunc("POST", "/eak", h.CreateExternalAccountKey) // TODO: authnz
 }

authority/admin/db.go

@@ -7,6 +7,8 @@ import (
 
 	"github.com/pkg/errors"
 	"go.step.sm/linkedca"
+
+	"github.com/smallstep/certificates/authority/admin/eak"
 )
 
 const (
@@ -67,6 +69,8 @@ type DB interface {
 	GetAdmins(ctx context.Context) ([]*linkedca.Admin, error)
 	UpdateAdmin(ctx context.Context, admin *linkedca.Admin) error
 	DeleteAdmin(ctx context.Context, id string) error
+
+	CreateExternalAccountKey(ctx context.Context, name string) (*eak.ExternalAccountKey, error)
 }
 
 // MockDB is an implementation of the DB interface that should only be used as
@@ -84,6 +88,8 @@ type MockDB struct {
 	MockUpdateAdmin func(ctx context.Context, adm *linkedca.Admin) error
 	MockDeleteAdmin func(ctx context.Context, id string) error
 
+	MockCreateExternalAccountKey func(ctx context.Context, name string) (*eak.ExternalAccountKey, error)
+
 	MockError error
 	MockRet1  interface{}
 }
@@ -177,3 +183,10 @@ func (m *MockDB) DeleteAdmin(ctx context.Context, id string) error {
 	}
 	return m.MockError
 }
+
+func (m *MockDB) CreateExternalAccountKey(ctx context.Context, name string) (*eak.ExternalAccountKey, error) {
+	if m.MockCreateExternalAccountKey != nil {
+		return m.MockCreateExternalAccountKey(ctx, name)
+	}
+	return m.MockRet1.(*eak.ExternalAccountKey), m.MockError
+}

authority/admin/db/nosql/eak.go

@@ -0,0 +1,51 @@
+package nosql
+
+import (
+	"context"
+	"crypto/rand"
+	"time"
+
+	"github.com/smallstep/certificates/authority/admin/eak"
+)
+
+type dbExternalAccountKey struct {
+	ID        string    `json:"id"`
+	Name      string    `json:"name"`
+	AccountID string    `json:"accountID,omitempty"`
+	KeyBytes  []byte    `json:"key,omitempty"`
+	CreatedAt time.Time `json:"createdAt"`
+	BoundAt   time.Time `json:"boundAt"`
+}
+
+// CreateExternalAccountKey creates a new External Account Binding key
+func (db *DB) CreateExternalAccountKey(ctx context.Context, name string) (*eak.ExternalAccountKey, error) {
+	keyID, err := randID()
+	if err != nil {
+		return nil, err
+	}
+
+	random := make([]byte, 32)
+	_, err = rand.Read(random)
+	if err != nil {
+		return nil, err
+	}
+
+	dbeak := &dbExternalAccountKey{
+		ID:        keyID,
+		Name:      name,
+		KeyBytes:  random,
+		CreatedAt: clock.Now(),
+	}
+
+	if err = db.save(ctx, keyID, dbeak, nil, "external_account_key", externalAccountKeyTable); err != nil {
+		return nil, err
+	}
+	return &eak.ExternalAccountKey{
+		ID:        dbeak.ID,
+		Name:      dbeak.Name,
+		AccountID: dbeak.AccountID,
+		KeyBytes:  dbeak.KeyBytes,
+		CreatedAt: dbeak.CreatedAt,
+		BoundAt:   dbeak.BoundAt,
+	}, nil
+}

authority/admin/db/nosql/nosql.go

@@ -13,6 +13,7 @@ import (
 var (
 	adminsTable             = []byte("admins")
 	provisionersTable       = []byte("provisioners")
+	externalAccountKeyTable = []byte("acme_external_account_keys")
 )
 
 // DB is a struct that implements the AdminDB interface.
@@ -23,7 +24,7 @@ type DB struct {
 
 // New configures and returns a new Authority DB backend implemented using a nosql DB.
 func New(db nosqlDB.DB, authorityID string) (*DB, error) {
-	tables := [][]byte{adminsTable, provisionersTable}
+	tables := [][]byte{adminsTable, provisionersTable, externalAccountKeyTable}
 	for _, b := range tables {
 		if err := db.CreateTable(b); err != nil {
 			return nil, errors.Wrapf(err, "error creating table %s",

authority/admin/eak/eak.go

@@ -0,0 +1,12 @@
+package eak
+
+import "time"
+
+type ExternalAccountKey struct {
+	ID        string    `json:"id"`
+	Name      string    `json:"name"`
+	AccountID string    `json:"-"`
+	KeyBytes  []byte    `json:"-"`
+	CreatedAt time.Time `json:"createdAt"`
+	BoundAt   time.Time `json:"boundAt,omitempty"`
+}

authority/provisioner/acme.go

@@ -17,6 +17,7 @@ type ACME struct {
 	Type       string   `json:"type"`
 	Name       string   `json:"name"`
 	ForceCN    bool     `json:"forceCN,omitempty"`
+	RequireEAB bool     `json:"requireEAB,omitempty"`
 	Claims     *Claims  `json:"claims,omitempty"`
 	Options    *Options `json:"options,omitempty"`
 	claimer    *Claimer