certificates/api/api.go
2020-01-28 13:28:16 -08:00

553 lines
16 KiB
Go

package api
import (
"context"
"crypto/dsa"
"crypto/ecdsa"
"crypto/rsa"
"crypto/tls"
"crypto/x509"
"encoding/asn1"
"encoding/base64"
"encoding/json"
"encoding/pem"
"fmt"
"net/http"
"strconv"
"strings"
"time"
"github.com/go-chi/chi"
"github.com/pkg/errors"
"github.com/smallstep/certificates/authority"
"github.com/smallstep/certificates/authority/provisioner"
"github.com/smallstep/certificates/logging"
"github.com/smallstep/cli/crypto/tlsutil"
)
// Authority is the interface implemented by a CA authority.
type Authority interface {
SSHAuthority
// context specifies the Authorize[Sign|Revoke|etc.] method.
Authorize(ctx context.Context, ott string) ([]provisioner.SignOption, error)
AuthorizeSign(ott string) ([]provisioner.SignOption, error)
GetTLSOptions() *tlsutil.TLSOptions
Root(shasum string) (*x509.Certificate, error)
Sign(cr *x509.CertificateRequest, opts provisioner.Options, signOpts ...provisioner.SignOption) ([]*x509.Certificate, error)
Renew(peer *x509.Certificate) ([]*x509.Certificate, error)
LoadProvisionerByCertificate(*x509.Certificate) (provisioner.Interface, error)
LoadProvisionerByID(string) (provisioner.Interface, error)
GetProvisioners(cursor string, limit int) (provisioner.List, string, error)
Revoke(context.Context, *authority.RevokeOptions) error
GetEncryptedKey(kid string) (string, error)
GetRoots() (federation []*x509.Certificate, err error)
GetFederation() ([]*x509.Certificate, error)
Version() authority.Version
}
// TimeDuration is an alias of provisioner.TimeDuration
type TimeDuration = provisioner.TimeDuration
// NewTimeDuration returns a TimeDuration with the defined time.
func NewTimeDuration(t time.Time) TimeDuration {
return provisioner.NewTimeDuration(t)
}
// ParseTimeDuration returns a new TimeDuration parsing the RFC 3339 time or
// time.Duration string.
func ParseTimeDuration(s string) (TimeDuration, error) {
return provisioner.ParseTimeDuration(s)
}
// Certificate wraps a *x509.Certificate and adds the json.Marshaler interface.
type Certificate struct {
*x509.Certificate
}
// NewCertificate is a helper method that returns a Certificate from a
// *x509.Certificate.
func NewCertificate(cr *x509.Certificate) Certificate {
return Certificate{
Certificate: cr,
}
}
// reset sets the inner x509.CertificateRequest to nil
func (c *Certificate) reset() {
if c != nil {
c.Certificate = nil
}
}
// MarshalJSON implements the json.Marshaler interface. The certificate is
// quoted string using the PEM encoding.
func (c Certificate) MarshalJSON() ([]byte, error) {
if c.Certificate == nil {
return []byte("null"), nil
}
block := pem.EncodeToMemory(&pem.Block{
Type: "CERTIFICATE",
Bytes: c.Raw,
})
return json.Marshal(string(block))
}
// UnmarshalJSON implements the json.Unmarshaler interface. The certificate is
// expected to be a quoted string using the PEM encoding.
func (c *Certificate) UnmarshalJSON(data []byte) error {
var s string
if err := json.Unmarshal(data, &s); err != nil {
return errors.Wrap(err, "error decoding certificate")
}
// Make sure the inner x509.Certificate is nil
if s == "null" || s == "" {
c.reset()
return nil
}
block, _ := pem.Decode([]byte(s))
if block == nil {
return errors.New("error decoding certificate")
}
cert, err := x509.ParseCertificate(block.Bytes)
if err != nil {
return errors.Wrap(err, "error decoding certificate")
}
c.Certificate = cert
return nil
}
// CertificateRequest wraps a *x509.CertificateRequest and adds the
// json.Unmarshaler interface.
type CertificateRequest struct {
*x509.CertificateRequest
}
// NewCertificateRequest is a helper method that returns a CertificateRequest
// from a *x509.CertificateRequest.
func NewCertificateRequest(cr *x509.CertificateRequest) CertificateRequest {
return CertificateRequest{
CertificateRequest: cr,
}
}
// reset sets the inner x509.CertificateRequest to nil
func (c *CertificateRequest) reset() {
if c != nil {
c.CertificateRequest = nil
}
}
// MarshalJSON implements the json.Marshaler interface. The certificate request
// is a quoted string using the PEM encoding.
func (c CertificateRequest) MarshalJSON() ([]byte, error) {
if c.CertificateRequest == nil {
return []byte("null"), nil
}
block := pem.EncodeToMemory(&pem.Block{
Type: "CERTIFICATE REQUEST",
Bytes: c.Raw,
})
return json.Marshal(string(block))
}
// UnmarshalJSON implements the json.Unmarshaler interface. The certificate
// request is expected to be a quoted string using the PEM encoding.
func (c *CertificateRequest) UnmarshalJSON(data []byte) error {
var s string
if err := json.Unmarshal(data, &s); err != nil {
return errors.Wrap(err, "error decoding csr")
}
// Make sure the inner x509.CertificateRequest is nil
if s == "null" || s == "" {
c.reset()
return nil
}
block, _ := pem.Decode([]byte(s))
if block == nil {
return errors.New("error decoding csr")
}
cr, err := x509.ParseCertificateRequest(block.Bytes)
if err != nil {
return errors.Wrap(err, "error decoding csr")
}
c.CertificateRequest = cr
return nil
}
// Router defines a common router interface.
type Router interface {
// MethodFunc adds routes for `pattern` that matches
// the `method` HTTP method.
MethodFunc(method, pattern string, h http.HandlerFunc)
}
// RouterHandler is the interface that a HTTP handler that manages multiple
// endpoints will implement.
type RouterHandler interface {
Route(r Router)
}
// VersionResponse is the response object that returns the version of the
// server.
type VersionResponse struct {
Version string `json:"version"`
RequireClientAuthentication bool `json:"requireClientAuthentication,omitempty"`
}
// HealthResponse is the response object that returns the health of the server.
type HealthResponse struct {
Status string `json:"status"`
}
// RootResponse is the response object that returns the PEM of a root certificate.
type RootResponse struct {
RootPEM Certificate `json:"ca"`
}
// SignRequest is the request body for a certificate signature request.
type SignRequest struct {
CsrPEM CertificateRequest `json:"csr"`
OTT string `json:"ott"`
NotAfter TimeDuration `json:"notAfter"`
NotBefore TimeDuration `json:"notBefore"`
}
// ProvisionersResponse is the response object that returns the list of
// provisioners.
type ProvisionersResponse struct {
Provisioners provisioner.List `json:"provisioners"`
NextCursor string `json:"nextCursor"`
}
// ProvisionerKeyResponse is the response object that returns the encrypted key
// of a provisioner.
type ProvisionerKeyResponse struct {
Key string `json:"key"`
}
// Validate checks the fields of the SignRequest and returns nil if they are ok
// or an error if something is wrong.
func (s *SignRequest) Validate() error {
if s.CsrPEM.CertificateRequest == nil {
return BadRequest(errors.New("missing csr"))
}
if err := s.CsrPEM.CertificateRequest.CheckSignature(); err != nil {
return BadRequest(errors.Wrap(err, "invalid csr"))
}
if s.OTT == "" {
return BadRequest(errors.New("missing ott"))
}
return nil
}
// SignResponse is the response object of the certificate signature request.
type SignResponse struct {
ServerPEM Certificate `json:"crt"`
CaPEM Certificate `json:"ca"`
CertChainPEM []Certificate `json:"certChain"`
TLSOptions *tlsutil.TLSOptions `json:"tlsOptions,omitempty"`
TLS *tls.ConnectionState `json:"-"`
}
// RootsResponse is the response object of the roots request.
type RootsResponse struct {
Certificates []Certificate `json:"crts"`
}
// FederationResponse is the response object of the federation request.
type FederationResponse struct {
Certificates []Certificate `json:"crts"`
}
// caHandler is the type used to implement the different CA HTTP endpoints.
type caHandler struct {
Authority Authority
}
// New creates a new RouterHandler with the CA endpoints.
func New(authority Authority) RouterHandler {
return &caHandler{
Authority: authority,
}
}
func (h *caHandler) Route(r Router) {
r.MethodFunc("GET", "/version", h.Version)
r.MethodFunc("GET", "/health", h.Health)
r.MethodFunc("GET", "/root/{sha}", h.Root)
r.MethodFunc("POST", "/sign", h.Sign)
r.MethodFunc("POST", "/renew", h.Renew)
r.MethodFunc("POST", "/revoke", h.Revoke)
r.MethodFunc("GET", "/provisioners", h.Provisioners)
r.MethodFunc("GET", "/provisioners/{kid}/encrypted-key", h.ProvisionerKey)
r.MethodFunc("GET", "/roots", h.Roots)
r.MethodFunc("GET", "/federation", h.Federation)
// SSH CA
r.MethodFunc("POST", "/ssh/sign", h.SSHSign)
r.MethodFunc("POST", "/ssh/renew", h.SSHRenew)
r.MethodFunc("POST", "/ssh/revoke", h.SSHRevoke)
r.MethodFunc("POST", "/ssh/rekey", h.SSHRekey)
r.MethodFunc("GET", "/ssh/roots", h.SSHRoots)
r.MethodFunc("GET", "/ssh/federation", h.SSHFederation)
r.MethodFunc("POST", "/ssh/config", h.SSHConfig)
r.MethodFunc("POST", "/ssh/config/{type}", h.SSHConfig)
r.MethodFunc("POST", "/ssh/check-host", h.SSHCheckHost)
r.MethodFunc("GET", "/ssh/get-hosts", h.SSHGetHosts)
r.MethodFunc("POST", "/ssh/bastion", h.SSHBastion)
// For compatibility with old code:
r.MethodFunc("POST", "/re-sign", h.Renew)
r.MethodFunc("POST", "/sign-ssh", h.SSHSign)
}
// Version is an HTTP handler that returns the version of the server.
func (h *caHandler) Version(w http.ResponseWriter, r *http.Request) {
v := h.Authority.Version()
JSON(w, VersionResponse{
Version: v.Version,
RequireClientAuthentication: v.RequireClientAuthentication,
})
}
// Health is an HTTP handler that returns the status of the server.
func (h *caHandler) Health(w http.ResponseWriter, r *http.Request) {
JSON(w, HealthResponse{Status: "ok"})
}
// Root is an HTTP handler that using the SHA256 from the URL, returns the root
// certificate for the given SHA256.
func (h *caHandler) Root(w http.ResponseWriter, r *http.Request) {
sha := chi.URLParam(r, "sha")
sum := strings.ToLower(strings.Replace(sha, "-", "", -1))
// Load root certificate with the
cert, err := h.Authority.Root(sum)
if err != nil {
WriteError(w, NotFound(errors.Wrapf(err, "%s was not found", r.RequestURI)))
return
}
JSON(w, &RootResponse{RootPEM: Certificate{cert}})
}
func certChainToPEM(certChain []*x509.Certificate) []Certificate {
certChainPEM := make([]Certificate, 0, len(certChain))
for _, c := range certChain {
certChainPEM = append(certChainPEM, Certificate{c})
}
return certChainPEM
}
// Sign is an HTTP handler that reads a certificate request and an
// one-time-token (ott) from the body and creates a new certificate with the
// information in the certificate request.
func (h *caHandler) Sign(w http.ResponseWriter, r *http.Request) {
var body SignRequest
if err := ReadJSON(r.Body, &body); err != nil {
WriteError(w, BadRequest(errors.Wrap(err, "error reading request body")))
return
}
logOtt(w, body.OTT)
if err := body.Validate(); err != nil {
WriteError(w, err)
return
}
opts := provisioner.Options{
NotBefore: body.NotBefore,
NotAfter: body.NotAfter,
}
signOpts, err := h.Authority.AuthorizeSign(body.OTT)
if err != nil {
WriteError(w, Unauthorized(err))
return
}
certChain, err := h.Authority.Sign(body.CsrPEM.CertificateRequest, opts, signOpts...)
if err != nil {
WriteError(w, Forbidden(err))
return
}
certChainPEM := certChainToPEM(certChain)
var caPEM Certificate
if len(certChainPEM) > 0 {
caPEM = certChainPEM[1]
}
logCertificate(w, certChain[0])
JSONStatus(w, &SignResponse{
ServerPEM: certChainPEM[0],
CaPEM: caPEM,
CertChainPEM: certChainPEM,
TLSOptions: h.Authority.GetTLSOptions(),
}, http.StatusCreated)
}
// Renew uses the information of certificate in the TLS connection to create a
// new one.
func (h *caHandler) Renew(w http.ResponseWriter, r *http.Request) {
if r.TLS == nil || len(r.TLS.PeerCertificates) == 0 {
WriteError(w, BadRequest(errors.New("missing peer certificate")))
return
}
certChain, err := h.Authority.Renew(r.TLS.PeerCertificates[0])
if err != nil {
WriteError(w, Forbidden(err))
return
}
certChainPEM := certChainToPEM(certChain)
var caPEM Certificate
if len(certChainPEM) > 0 {
caPEM = certChainPEM[1]
}
logCertificate(w, certChain[0])
JSONStatus(w, &SignResponse{
ServerPEM: certChainPEM[0],
CaPEM: caPEM,
CertChainPEM: certChainPEM,
TLSOptions: h.Authority.GetTLSOptions(),
}, http.StatusCreated)
}
// Provisioners returns the list of provisioners configured in the authority.
func (h *caHandler) Provisioners(w http.ResponseWriter, r *http.Request) {
cursor, limit, err := parseCursor(r)
if err != nil {
WriteError(w, BadRequest(err))
return
}
p, next, err := h.Authority.GetProvisioners(cursor, limit)
if err != nil {
WriteError(w, InternalServerError(err))
return
}
JSON(w, &ProvisionersResponse{
Provisioners: p,
NextCursor: next,
})
}
// ProvisionerKey returns the encrypted key of a provisioner by it's key id.
func (h *caHandler) ProvisionerKey(w http.ResponseWriter, r *http.Request) {
kid := chi.URLParam(r, "kid")
key, err := h.Authority.GetEncryptedKey(kid)
if err != nil {
WriteError(w, NotFound(err))
return
}
JSON(w, &ProvisionerKeyResponse{key})
}
// Roots returns all the root certificates for the CA.
func (h *caHandler) Roots(w http.ResponseWriter, r *http.Request) {
roots, err := h.Authority.GetRoots()
if err != nil {
WriteError(w, Forbidden(err))
return
}
certs := make([]Certificate, len(roots))
for i := range roots {
certs[i] = Certificate{roots[i]}
}
JSONStatus(w, &RootsResponse{
Certificates: certs,
}, http.StatusCreated)
}
// Federation returns all the public certificates in the federation.
func (h *caHandler) Federation(w http.ResponseWriter, r *http.Request) {
federated, err := h.Authority.GetFederation()
if err != nil {
WriteError(w, Forbidden(err))
return
}
certs := make([]Certificate, len(federated))
for i := range federated {
certs[i] = Certificate{federated[i]}
}
JSONStatus(w, &FederationResponse{
Certificates: certs,
}, http.StatusCreated)
}
var oidStepProvisioner = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 37476, 9000, 64, 1}
type stepProvisioner struct {
Type int
Name []byte
CredentialID []byte
}
func logOtt(w http.ResponseWriter, token string) {
if rl, ok := w.(logging.ResponseLogger); ok {
rl.WithFields(map[string]interface{}{
"ott": token,
})
}
}
func logCertificate(w http.ResponseWriter, cert *x509.Certificate) {
if rl, ok := w.(logging.ResponseLogger); ok {
m := map[string]interface{}{
"serial": cert.SerialNumber,
"subject": cert.Subject.CommonName,
"issuer": cert.Issuer.CommonName,
"valid-from": cert.NotBefore.Format(time.RFC3339),
"valid-to": cert.NotAfter.Format(time.RFC3339),
"public-key": fmtPublicKey(cert),
"certificate": base64.StdEncoding.EncodeToString(cert.Raw),
}
for _, ext := range cert.Extensions {
if ext.Id.Equal(oidStepProvisioner) {
val := &stepProvisioner{}
rest, err := asn1.Unmarshal(ext.Value, val)
if err != nil || len(rest) > 0 {
break
}
m["provisioner"] = fmt.Sprintf("%s (%s)", val.Name, val.CredentialID)
break
}
}
rl.WithFields(m)
}
}
func parseCursor(r *http.Request) (cursor string, limit int, err error) {
q := r.URL.Query()
cursor = q.Get("cursor")
if v := q.Get("limit"); len(v) > 0 {
limit, err = strconv.Atoi(v)
if err != nil {
return "", 0, errors.Wrapf(err, "error converting %s to integer", v)
}
}
return
}
// TODO: add support for Ed25519 once it's supported
func fmtPublicKey(cert *x509.Certificate) string {
var params string
switch pk := cert.PublicKey.(type) {
case *ecdsa.PublicKey:
params = pk.Curve.Params().Name
case *rsa.PublicKey:
params = strconv.Itoa(pk.Size() * 8)
case *dsa.PublicKey:
params = strconv.Itoa(pk.Q.BitLen() * 8)
default:
params = "unknown"
}
return fmt.Sprintf("%s %s", cert.PublicKeyAlgorithm, params)
}