distribution/registry/auth/token/accesscontroller.go
Doug Davis c4eb195cc1 Move challenge http status code logic
See: 3ea67df373/registry/handlers/app.go (L498)

Per the comment on line 498, this moves the logic of setting the http
status code into the serveJSON func, leaving the auth.Challenge.ServeHTTP()
func to just set the auth challenge header.

Signed-off-by: Doug Davis <dug@us.ibm.com>
2015-06-17 18:23:55 -07:00

273 lines
7.3 KiB
Go

package token
import (
"crypto"
"crypto/x509"
"encoding/pem"
"errors"
"fmt"
"io/ioutil"
"net/http"
"os"
"strings"
ctxu "github.com/docker/distribution/context"
"github.com/docker/distribution/registry/auth"
"github.com/docker/libtrust"
"golang.org/x/net/context"
)
// accessSet maps a typed, named resource to
// a set of actions requested or authorized.
type accessSet map[auth.Resource]actionSet
// newAccessSet constructs an accessSet from
// a variable number of auth.Access items.
func newAccessSet(accessItems ...auth.Access) accessSet {
accessSet := make(accessSet, len(accessItems))
for _, access := range accessItems {
resource := auth.Resource{
Type: access.Type,
Name: access.Name,
}
set, exists := accessSet[resource]
if !exists {
set = newActionSet()
accessSet[resource] = set
}
set.add(access.Action)
}
return accessSet
}
// contains returns whether or not the given access is in this accessSet.
func (s accessSet) contains(access auth.Access) bool {
actionSet, ok := s[access.Resource]
if ok {
return actionSet.contains(access.Action)
}
return false
}
// scopeParam returns a collection of scopes which can
// be used for a WWW-Authenticate challenge parameter.
// See https://tools.ietf.org/html/rfc6750#section-3
func (s accessSet) scopeParam() string {
scopes := make([]string, 0, len(s))
for resource, actionSet := range s {
actions := strings.Join(actionSet.keys(), ",")
scopes = append(scopes, fmt.Sprintf("%s:%s:%s", resource.Type, resource.Name, actions))
}
return strings.Join(scopes, " ")
}
// Errors used and exported by this package.
var (
ErrInsufficientScope = errors.New("insufficient scope")
ErrTokenRequired = errors.New("authorization token required")
)
// authChallenge implements the auth.Challenge interface.
type authChallenge struct {
err error
realm string
service string
accessSet accessSet
}
// Error returns the internal error string for this authChallenge.
func (ac *authChallenge) Error() string {
return ac.err.Error()
}
// Status returns the HTTP Response Status Code for this authChallenge.
func (ac *authChallenge) Status() int {
return http.StatusUnauthorized
}
// challengeParams constructs the value to be used in
// the WWW-Authenticate response challenge header.
// See https://tools.ietf.org/html/rfc6750#section-3
func (ac *authChallenge) challengeParams() string {
str := fmt.Sprintf("Bearer realm=%q,service=%q", ac.realm, ac.service)
if scope := ac.accessSet.scopeParam(); scope != "" {
str = fmt.Sprintf("%s,scope=%q", str, scope)
}
if ac.err == ErrInvalidToken || ac.err == ErrMalformedToken {
str = fmt.Sprintf("%s,error=%q", str, "invalid_token")
} else if ac.err == ErrInsufficientScope {
str = fmt.Sprintf("%s,error=%q", str, "insufficient_scope")
}
return str
}
// SetHeader sets the WWW-Authenticate value for the given header.
func (ac *authChallenge) SetHeader(header http.Header) {
header.Add("WWW-Authenticate", ac.challengeParams())
}
// ServeHttp handles writing the challenge response
// by setting the challenge header.
func (ac *authChallenge) ServeHTTP(w http.ResponseWriter, r *http.Request) {
ac.SetHeader(w.Header())
}
// accessController implements the auth.AccessController interface.
type accessController struct {
realm string
issuer string
service string
rootCerts *x509.CertPool
trustedKeys map[string]libtrust.PublicKey
}
// tokenAccessOptions is a convenience type for handling
// options to the contstructor of an accessController.
type tokenAccessOptions struct {
realm string
issuer string
service string
rootCertBundle string
}
// checkOptions gathers the necessary options
// for an accessController from the given map.
func checkOptions(options map[string]interface{}) (tokenAccessOptions, error) {
var opts tokenAccessOptions
keys := []string{"realm", "issuer", "service", "rootcertbundle"}
vals := make([]string, 0, len(keys))
for _, key := range keys {
val, ok := options[key].(string)
if !ok {
return opts, fmt.Errorf("token auth requires a valid option string: %q", key)
}
vals = append(vals, val)
}
opts.realm, opts.issuer, opts.service, opts.rootCertBundle = vals[0], vals[1], vals[2], vals[3]
return opts, nil
}
// newAccessController creates an accessController using the given options.
func newAccessController(options map[string]interface{}) (auth.AccessController, error) {
config, err := checkOptions(options)
if err != nil {
return nil, err
}
fp, err := os.Open(config.rootCertBundle)
if err != nil {
return nil, fmt.Errorf("unable to open token auth root certificate bundle file %q: %s", config.rootCertBundle, err)
}
defer fp.Close()
rawCertBundle, err := ioutil.ReadAll(fp)
if err != nil {
return nil, fmt.Errorf("unable to read token auth root certificate bundle file %q: %s", config.rootCertBundle, err)
}
var rootCerts []*x509.Certificate
pemBlock, rawCertBundle := pem.Decode(rawCertBundle)
for pemBlock != nil {
cert, err := x509.ParseCertificate(pemBlock.Bytes)
if err != nil {
return nil, fmt.Errorf("unable to parse token auth root certificate: %s", err)
}
rootCerts = append(rootCerts, cert)
pemBlock, rawCertBundle = pem.Decode(rawCertBundle)
}
if len(rootCerts) == 0 {
return nil, errors.New("token auth requires at least one token signing root certificate")
}
rootPool := x509.NewCertPool()
trustedKeys := make(map[string]libtrust.PublicKey, len(rootCerts))
for _, rootCert := range rootCerts {
rootPool.AddCert(rootCert)
pubKey, err := libtrust.FromCryptoPublicKey(crypto.PublicKey(rootCert.PublicKey))
if err != nil {
return nil, fmt.Errorf("unable to get public key from token auth root certificate: %s", err)
}
trustedKeys[pubKey.KeyID()] = pubKey
}
return &accessController{
realm: config.realm,
issuer: config.issuer,
service: config.service,
rootCerts: rootPool,
trustedKeys: trustedKeys,
}, nil
}
// Authorized handles checking whether the given request is authorized
// for actions on resources described by the given access items.
func (ac *accessController) Authorized(ctx context.Context, accessItems ...auth.Access) (context.Context, error) {
challenge := &authChallenge{
realm: ac.realm,
service: ac.service,
accessSet: newAccessSet(accessItems...),
}
req, err := ctxu.GetRequest(ctx)
if err != nil {
return nil, err
}
parts := strings.Split(req.Header.Get("Authorization"), " ")
if len(parts) != 2 || strings.ToLower(parts[0]) != "bearer" {
challenge.err = ErrTokenRequired
return nil, challenge
}
rawToken := parts[1]
token, err := NewToken(rawToken)
if err != nil {
challenge.err = err
return nil, challenge
}
verifyOpts := VerifyOptions{
TrustedIssuers: []string{ac.issuer},
AcceptedAudiences: []string{ac.service},
Roots: ac.rootCerts,
TrustedKeys: ac.trustedKeys,
}
if err = token.Verify(verifyOpts); err != nil {
challenge.err = err
return nil, challenge
}
accessSet := token.accessSet()
for _, access := range accessItems {
if !accessSet.contains(access) {
challenge.err = ErrInsufficientScope
return nil, challenge
}
}
return auth.WithUser(ctx, auth.UserInfo{Name: token.Claims.Subject}), nil
}
// init handles registering the token auth backend.
func init() {
auth.Register("token", auth.InitFunc(newAccessController))
}