Add simple implementation of token server

Token server implementation currently functional with existing docker 1.9.x release and latest distribution release.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
This commit is contained in:
Derek McGowan 2016-01-25 15:42:05 -08:00
parent caa2001e1f
commit eaa9da0be3
2 changed files with 370 additions and 0 deletions

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package main
import (
"encoding/json"
"flag"
"net/http"
"strings"
"github.com/Sirupsen/logrus"
"github.com/docker/distribution/context"
"github.com/docker/distribution/registry/api/errcode"
"github.com/docker/distribution/registry/auth"
_ "github.com/docker/distribution/registry/auth/htpasswd"
"github.com/docker/libtrust"
"github.com/gorilla/mux"
)
func main() {
var (
issuer = &TokenIssuer{}
pkFile string
addr string
debug bool
err error
passwdFile string
realm string
cert string
certKey string
)
flag.StringVar(&issuer.Issuer, "issuer", "distribution-token-server", "Issuer string for token")
flag.StringVar(&pkFile, "key", "", "Private key file")
flag.StringVar(&addr, "addr", "localhost:8080", "Address to listen on")
flag.BoolVar(&debug, "debug", false, "Debug mode")
flag.StringVar(&passwdFile, "passwd", ".htpasswd", "Passwd file")
flag.StringVar(&realm, "realm", "", "Authentication realm")
flag.StringVar(&cert, "tlscert", "", "Certificate file for TLS")
flag.StringVar(&certKey, "tlskey", "", "Certificate key for TLS")
flag.Parse()
if debug {
logrus.SetLevel(logrus.DebugLevel)
}
if pkFile == "" {
issuer.SigningKey, err = libtrust.GenerateECP256PrivateKey()
if err != nil {
logrus.Fatalf("Error generating private key: %v", err)
}
logrus.Debugf("Using newly generated key with id %s", issuer.SigningKey.KeyID())
} else {
issuer.SigningKey, err = libtrust.LoadKeyFile(pkFile)
if err != nil {
logrus.Fatalf("Error loading key file %s: %v", pkFile, err)
}
logrus.Debugf("Loaded private key with id %s", issuer.SigningKey.KeyID())
}
if realm == "" {
logrus.Fatalf("Must provide realm")
}
ac, err := auth.GetAccessController("htpasswd", map[string]interface{}{
"realm": realm,
"path": passwdFile,
})
if err != nil {
logrus.Fatalf("Error initializing access controller: %v", err)
}
ctx := context.Background()
ts := &tokenServer{
issuer: issuer,
accessController: ac,
}
router := mux.NewRouter()
router.Path("/token/").Methods("GET").Handler(handlerWithContext(ctx, ts.getToken))
if cert == "" {
err = http.ListenAndServe(addr, router)
} else if certKey == "" {
logrus.Fatalf("Must provide certficate and key")
} else {
err = http.ListenAndServeTLS(addr, cert, certKey, router)
}
if err != nil {
logrus.Infof("Error serving: %v", err)
}
}
// handlerWithContext wraps the given context-aware handler by setting up the
// request context from a base context.
func handlerWithContext(ctx context.Context, handler func(context.Context, http.ResponseWriter, *http.Request)) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ctx := context.WithRequest(ctx, r)
logger := context.GetRequestLogger(ctx)
ctx = context.WithLogger(ctx, logger)
handler(ctx, w, r)
})
}
func handleError(ctx context.Context, err error, w http.ResponseWriter) {
ctx, w = context.WithResponseWriter(ctx, w)
if serveErr := errcode.ServeJSON(w, err); serveErr != nil {
context.GetResponseLogger(ctx).Errorf("error sending error response: %v", serveErr)
return
}
context.GetResponseLogger(ctx).Info("application error")
}
type tokenServer struct {
issuer *TokenIssuer
accessController auth.AccessController
}
// getToken handles authenticating the request and authorizing access to the
// requested scopes.
func (ts *tokenServer) getToken(ctx context.Context, w http.ResponseWriter, r *http.Request) {
context.GetLogger(ctx).Info("getToken")
params := r.URL.Query()
service := params.Get("service")
scopeSpecifiers := params["scope"]
requestedAccessList := ResolveScopeSpecifiers(scopeSpecifiers)
authorizedCtx, err := ts.accessController.Authorized(ctx, requestedAccessList...)
if err != nil {
challenge, ok := err.(auth.Challenge)
if !ok {
handleError(ctx, err, w)
return
}
// Get response context.
ctx, w = context.WithResponseWriter(ctx, w)
challenge.SetHeaders(w)
handleError(ctx, errcode.ErrorCodeUnauthorized.WithDetail(challenge.Error()), w)
context.GetResponseLogger(ctx).Info("authentication challenged")
return
}
ctx = authorizedCtx
// TODO(dmcgowan): handle case where this could panic?
username := ctx.Value("auth.user.name").(string)
ctx = context.WithValue(ctx, "acctSubject", username)
ctx = context.WithLogger(ctx, context.GetLogger(ctx, "acctSubject"))
context.GetLogger(ctx).Info("authenticated client")
ctx = context.WithValue(ctx, "requestedAccess", requestedAccessList)
ctx = context.WithLogger(ctx, context.GetLogger(ctx, "requestedAccess"))
scopePrefix := username + "/"
grantedAccessList := make([]auth.Access, 0, len(requestedAccessList))
for _, access := range requestedAccessList {
if access.Type != "repository" {
context.GetLogger(ctx).Debugf("Skipping unsupported resource type: %s", access.Type)
continue
}
if !strings.HasPrefix(access.Name, scopePrefix) {
context.GetLogger(ctx).Debugf("Resource scope not allowed: %s", access.Name)
continue
}
grantedAccessList = append(grantedAccessList, access)
}
ctx = context.WithValue(ctx, "grantedAccess", grantedAccessList)
ctx = context.WithLogger(ctx, context.GetLogger(ctx, "grantedAccess"))
token, err := ts.issuer.CreateJWT(username, service, grantedAccessList)
if err != nil {
handleError(ctx, err, w)
return
}
context.GetLogger(ctx).Info("authorized client")
// Get response context.
ctx, w = context.WithResponseWriter(ctx, w)
w.Header().Set("Content-Type", "application/json")
json.NewEncoder(w).Encode(map[string]string{"token": token})
context.GetResponseLogger(ctx).Info("getToken complete")
}

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package main
import (
"crypto"
"crypto/rand"
"encoding/base64"
"encoding/json"
"fmt"
"io"
"strings"
"time"
"github.com/docker/distribution/registry/auth"
"github.com/docker/distribution/registry/auth/token"
"github.com/docker/libtrust"
)
// ResolveScopeSpecifiers converts a list of scope specifiers from a token
// request's `scope` query parameters into a list of standard access objects.
func ResolveScopeSpecifiers(scopeSpecs []string) []auth.Access {
requestedAccessSet := make(map[auth.Access]struct{}, 2*len(scopeSpecs))
for _, scopeSpecifier := range scopeSpecs {
// There should be 3 parts, separated by a `:` character.
parts := strings.SplitN(scopeSpecifier, ":", 3)
if len(parts) != 3 {
// Ignore malformed scope specifiers.
continue
}
resourceType, resourceName, actions := parts[0], parts[1], parts[2]
// Actions should be a comma-separated list of actions.
for _, action := range strings.Split(actions, ",") {
requestedAccess := auth.Access{
Resource: auth.Resource{
Type: resourceType,
Name: resourceName,
},
Action: action,
}
// Add this access to the requested access set.
requestedAccessSet[requestedAccess] = struct{}{}
}
}
requestedAccessList := make([]auth.Access, 0, len(requestedAccessSet))
for requestedAccess := range requestedAccessSet {
requestedAccessList = append(requestedAccessList, requestedAccess)
}
return requestedAccessList
}
// TokenIssuer represents an issuer capable of generating JWT tokens
type TokenIssuer struct {
Issuer string
SigningKey libtrust.PrivateKey
Expiration time.Duration
}
// CreateJWT creates and signs a JSON Web Token for the given account and
// audience with the granted access.
func (issuer *TokenIssuer) CreateJWT(subject string, audience string, grantedAccessList []auth.Access) (string, error) {
// Make a set of access entries to put in the token's claimset.
resourceActionSets := make(map[auth.Resource]map[string]struct{}, len(grantedAccessList))
for _, access := range grantedAccessList {
actionSet, exists := resourceActionSets[access.Resource]
if !exists {
actionSet = map[string]struct{}{}
resourceActionSets[access.Resource] = actionSet
}
actionSet[access.Action] = struct{}{}
}
accessEntries := make([]token.ResourceActions, 0, len(resourceActionSets))
for resource, actionSet := range resourceActionSets {
actions := make([]string, 0, len(actionSet))
for action := range actionSet {
actions = append(actions, action)
}
accessEntries = append(accessEntries, token.ResourceActions{
Type: resource.Type,
Name: resource.Name,
Actions: actions,
})
}
randomBytes := make([]byte, 15)
_, err := io.ReadFull(rand.Reader, randomBytes)
if err != nil {
return "", err
}
randomID := base64.URLEncoding.EncodeToString(randomBytes)
now := time.Now()
signingHash := crypto.SHA256
var alg string
switch issuer.SigningKey.KeyType() {
case "RSA":
alg = "RS256"
case "EC":
alg = "ES256"
default:
panic(fmt.Errorf("unsupported signing key type %q", issuer.SigningKey.KeyType()))
}
joseHeader := map[string]interface{}{
"typ": "JWT",
"alg": alg,
}
if x5c := issuer.SigningKey.GetExtendedField("x5c"); x5c != nil {
joseHeader["x5c"] = x5c
} else {
joseHeader["jwk"] = issuer.SigningKey.PublicKey()
}
exp := issuer.Expiration
if exp == 0 {
exp = 5 * time.Minute
}
claimSet := map[string]interface{}{
"iss": issuer.Issuer,
"sub": subject,
"aud": audience,
"exp": now.Add(exp).Unix(),
"nbf": now.Unix(),
"iat": now.Unix(),
"jti": randomID,
"access": accessEntries,
}
var (
joseHeaderBytes []byte
claimSetBytes []byte
)
if joseHeaderBytes, err = json.Marshal(joseHeader); err != nil {
return "", fmt.Errorf("unable to encode jose header: %s", err)
}
if claimSetBytes, err = json.Marshal(claimSet); err != nil {
return "", fmt.Errorf("unable to encode claim set: %s", err)
}
encodedJoseHeader := joseBase64Encode(joseHeaderBytes)
encodedClaimSet := joseBase64Encode(claimSetBytes)
encodingToSign := fmt.Sprintf("%s.%s", encodedJoseHeader, encodedClaimSet)
var signatureBytes []byte
if signatureBytes, _, err = issuer.SigningKey.Sign(strings.NewReader(encodingToSign), signingHash); err != nil {
return "", fmt.Errorf("unable to sign jwt payload: %s", err)
}
signature := joseBase64Encode(signatureBytes)
return fmt.Sprintf("%s.%s", encodingToSign, signature), nil
}
func joseBase64Encode(data []byte) string {
return strings.TrimRight(base64.URLEncoding.EncodeToString(data), "=")
}