docker: split private token helper functions to reusable pkg

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

remotes/docker/auth/fetch.go

@@ -0,0 +1,219 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package auth
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/containerd/containerd/log"
+	"github.com/pkg/errors"
+	"golang.org/x/net/context/ctxhttp"
+)
+
+var (
+	// ErrNoToken is returned if a request is successful but the body does not
+	// contain an authorization token.
+	ErrNoToken = errors.New("authorization server did not include a token in the response")
+)
+
+// ErrUnexpectedStatus is returned if a token request returned with unexpected HTTP status
+type ErrUnexpectedStatus struct {
+	Status     string
+	StatusCode int
+	Body       []byte
+}
+
+func (e ErrUnexpectedStatus) Error() string {
+	return fmt.Sprintf("unexpected status: %s", e.Status)
+}
+
+func newUnexpectedStatusErr(resp *http.Response) error {
+	var b []byte
+	if resp.Body != nil {
+		b, _ = ioutil.ReadAll(io.LimitReader(resp.Body, 64000)) // 64KB
+	}
+	return ErrUnexpectedStatus{Status: resp.Status, StatusCode: resp.StatusCode, Body: b}
+}
+
+func GenerateTokenOptions(ctx context.Context, host, username, secret string, c Challenge) (TokenOptions, error) {
+	realm, ok := c.Parameters["realm"]
+	if !ok {
+		return TokenOptions{}, errors.New("no realm specified for token auth challenge")
+	}
+
+	realmURL, err := url.Parse(realm)
+	if err != nil {
+		return TokenOptions{}, errors.Wrap(err, "invalid token auth challenge realm")
+	}
+
+	to := TokenOptions{
+		Realm:    realmURL.String(),
+		Service:  c.Parameters["service"],
+		Username: username,
+		Secret:   secret,
+	}
+
+	scope, ok := c.Parameters["scope"]
+	if ok {
+		to.Scopes = append(to.Scopes, scope)
+	} else {
+		log.G(ctx).WithField("host", host).Debug("no scope specified for token auth challenge")
+	}
+
+	return to, nil
+}
+
+// TokenOptions are optios for requesting a token
+type TokenOptions struct {
+	Realm    string
+	Service  string
+	Scopes   []string
+	Username string
+	Secret   string
+}
+
+type postTokenResponse struct {
+	AccessToken  string    `json:"access_token"`
+	RefreshToken string    `json:"refresh_token"`
+	ExpiresIn    int       `json:"expires_in"`
+	IssuedAt     time.Time `json:"issued_at"`
+	Scope        string    `json:"scope"`
+}
+
+func FetchTokenWithOAuth(ctx context.Context, client *http.Client, headers http.Header, clientID string, to TokenOptions) (string, error) {
+	form := url.Values{}
+	if len(to.Scopes) > 0 {
+		form.Set("scope", strings.Join(to.Scopes, " "))
+	}
+	form.Set("service", to.Service)
+	form.Set("client_id", clientID)
+
+	if to.Username == "" {
+		form.Set("grant_type", "refresh_token")
+		form.Set("refresh_token", to.Secret)
+	} else {
+		form.Set("grant_type", "password")
+		form.Set("username", to.Username)
+		form.Set("password", to.Secret)
+	}
+
+	req, err := http.NewRequest("POST", to.Realm, strings.NewReader(form.Encode()))
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded; charset=utf-8")
+	if headers != nil {
+		for k, v := range headers {
+			req.Header[k] = append(req.Header[k], v...)
+		}
+	}
+
+	resp, err := ctxhttp.Do(ctx, client, req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 400 {
+		return "", errors.WithStack(newUnexpectedStatusErr(resp))
+	}
+
+	decoder := json.NewDecoder(resp.Body)
+
+	var tr postTokenResponse
+	if err = decoder.Decode(&tr); err != nil {
+		return "", errors.Errorf("unable to decode token response: %s", err)
+	}
+
+	return tr.AccessToken, nil
+}
+
+type getTokenResponse struct {
+	Token        string    `json:"token"`
+	AccessToken  string    `json:"access_token"`
+	ExpiresIn    int       `json:"expires_in"`
+	IssuedAt     time.Time `json:"issued_at"`
+	RefreshToken string    `json:"refresh_token"`
+}
+
+// FetchToken fetches a token using a GET request
+func FetchToken(ctx context.Context, client *http.Client, headers http.Header, to TokenOptions) (string, error) {
+	req, err := http.NewRequest("GET", to.Realm, nil)
+	if err != nil {
+		return "", err
+	}
+
+	if headers != nil {
+		for k, v := range headers {
+			req.Header[k] = append(req.Header[k], v...)
+		}
+	}
+
+	reqParams := req.URL.Query()
+
+	if to.Service != "" {
+		reqParams.Add("service", to.Service)
+	}
+
+	for _, scope := range to.Scopes {
+		reqParams.Add("scope", scope)
+	}
+
+	if to.Secret != "" {
+		req.SetBasicAuth(to.Username, to.Secret)
+	}
+
+	req.URL.RawQuery = reqParams.Encode()
+
+	resp, err := ctxhttp.Do(ctx, client, req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode < 200 || resp.StatusCode >= 400 {
+		return "", errors.WithStack(newUnexpectedStatusErr(resp))
+	}
+
+	decoder := json.NewDecoder(resp.Body)
+
+	var tr getTokenResponse
+	if err = decoder.Decode(&tr); err != nil {
+		return "", errors.Errorf("unable to decode token response: %s", err)
+	}
+
+	// `access_token` is equivalent to `token` and if both are specified
+	// the choice is undefined.  Canonicalize `access_token` by sticking
+	// things in `token`.
+	if tr.AccessToken != "" {
+		tr.Token = tr.AccessToken
+	}
+
+	if tr.Token == "" {
+		return "", ErrNoToken
+	}
+
+	return tr.Token, nil
+}

remotes/docker/auth/parse.go

@@ -14,7 +14,7 @@
    limitations under the License.
 */
 
-package docker
+package auth
 
 import (
 	"net/http"
@@ -22,31 +22,35 @@ import (
 	"strings"
 )
 
-type authenticationScheme byte
+// AuthenticationScheme defines scheme of the authentication method
+type AuthenticationScheme byte
 
 const (
-	basicAuth  authenticationScheme = 1 << iota // Defined in RFC 7617
+	// BasicAuth is scheme for Basic HTTP Authentication RFC 7617
-	digestAuth                                  // Defined in RFC 7616
+	BasicAuth AuthenticationScheme = 1 << iota
-	bearerAuth                                  // Defined in RFC 6750
+	// DigestAuth is scheme for HTTP Digest Access Authentication RFC 7616
+	DigestAuth
+	// BearerAuth is scheme for OAuth 2.0 Bearer Tokens RFC 6750
+	BearerAuth
 )
 
-// challenge carries information from a WWW-Authenticate response header.
+// Challenge carries information from a WWW-Authenticate response header.
 // See RFC 2617.
-type challenge struct {
+type Challenge struct {
 	// scheme is the auth-scheme according to RFC 2617
-	scheme authenticationScheme
+	Scheme AuthenticationScheme
 
 	// parameters are the auth-params according to RFC 2617
-	parameters map[string]string
+	Parameters map[string]string
 }
 
-type byScheme []challenge
+type byScheme []Challenge
 
 func (bs byScheme) Len() int      { return len(bs) }
 func (bs byScheme) Swap(i, j int) { bs[i], bs[j] = bs[j], bs[i] }
 
 // Sort in priority order: token > digest > basic
-func (bs byScheme) Less(i, j int) bool { return bs[i].scheme > bs[j].scheme }
+func (bs byScheme) Less(i, j int) bool { return bs[i].Scheme > bs[j].Scheme }
 
 // Octet types from RFC 2616.
 type octetType byte
@@ -90,22 +94,23 @@ func init() {
 	}
 }
 
-func parseAuthHeader(header http.Header) []challenge {
+// ParseAuthHeader parses challenges from WWW-Authenticate header
-	challenges := []challenge{}
+func ParseAuthHeader(header http.Header) []Challenge {
+	challenges := []Challenge{}
 	for _, h := range header[http.CanonicalHeaderKey("WWW-Authenticate")] {
 		v, p := parseValueAndParams(h)
-		var s authenticationScheme
+		var s AuthenticationScheme
 		switch v {
 		case "basic":
-			s = basicAuth
+			s = BasicAuth
 		case "digest":
-			s = digestAuth
+			s = DigestAuth
 		case "bearer":
-			s = bearerAuth
+			s = BearerAuth
 		default:
 			continue
 		}
-		challenges = append(challenges, challenge{scheme: s, parameters: p})
+		challenges = append(challenges, Challenge{Scheme: s, Parameters: p})
 	}
 	sort.Stable(byScheme(challenges))
 	return challenges

remotes/docker/authorizer.go

@@ -19,21 +19,16 @@ package docker
 import (
 	"context"
 	"encoding/base64"
-	"encoding/json"
 	"fmt"
-	"io"
-	"io/ioutil"
 	"net/http"
-	"net/url"
 	"strings"
 	"sync"
-	"time"
 
 	"github.com/containerd/containerd/errdefs"
 	"github.com/containerd/containerd/log"
+	"github.com/containerd/containerd/remotes/docker/auth"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
-	"golang.org/x/net/context/ctxhttp"
 )
 
 type dockerAuthorizer struct {
@@ -135,8 +130,8 @@ func (a *dockerAuthorizer) AddResponses(ctx context.Context, responses []*http.R
 
 	a.mu.Lock()
 	defer a.mu.Unlock()
-	for _, c := range parseAuthHeader(last.Header) {
+	for _, c := range auth.ParseAuthHeader(last.Header) {
-		if c.scheme == bearerAuth {
+		if c.Scheme == auth.BearerAuth {
 			if err := invalidAuthorization(c, responses); err != nil {
 				delete(a.handlers, host)
 				return err
@@ -152,26 +147,35 @@ func (a *dockerAuthorizer) AddResponses(ctx context.Context, responses []*http.R
 				return nil
 			}
 
-			common, err := a.generateTokenOptions(ctx, host, c)
+			var username, secret string
+			if a.credentials != nil {
+				var err error
+				username, secret, err = a.credentials(host)
+				if err != nil {
+					return err
+				}
+			}
+
+			common, err := auth.GenerateTokenOptions(ctx, host, username, secret, c)
 			if err != nil {
 				return err
 			}
 
-			a.handlers[host] = newAuthHandler(a.client, a.header, c.scheme, common)
+			a.handlers[host] = newAuthHandler(a.client, a.header, c.Scheme, common)
 			return nil
-		} else if c.scheme == basicAuth && a.credentials != nil {
+		} else if c.Scheme == auth.BasicAuth && a.credentials != nil {
 			username, secret, err := a.credentials(host)
 			if err != nil {
 				return err
 			}
 
 			if username != "" && secret != "" {
-				common := tokenOptions{
+				common := auth.TokenOptions{
-					username: username,
+					Username: username,
-					secret:   secret,
+					Secret:   secret,
 				}
 
-				a.handlers[host] = newAuthHandler(a.client, a.header, c.scheme, common)
+				a.handlers[host] = newAuthHandler(a.client, a.header, c.Scheme, common)
 				return nil
 			}
 		}
@@ -179,38 +183,6 @@ func (a *dockerAuthorizer) AddResponses(ctx context.Context, responses []*http.R
 	return errors.Wrap(errdefs.ErrNotImplemented, "failed to find supported auth scheme")
 }
 
-func (a *dockerAuthorizer) generateTokenOptions(ctx context.Context, host string, c challenge) (tokenOptions, error) {
-	realm, ok := c.parameters["realm"]
-	if !ok {
-		return tokenOptions{}, errors.New("no realm specified for token auth challenge")
-	}
-
-	realmURL, err := url.Parse(realm)
-	if err != nil {
-		return tokenOptions{}, errors.Wrap(err, "invalid token auth challenge realm")
-	}
-
-	to := tokenOptions{
-		realm:   realmURL.String(),
-		service: c.parameters["service"],
-	}
-
-	scope, ok := c.parameters["scope"]
-	if ok {
-		to.scopes = append(to.scopes, scope)
-	} else {
-		log.G(ctx).WithField("host", host).Debug("no scope specified for token auth challenge")
-	}
-
-	if a.credentials != nil {
-		to.username, to.secret, err = a.credentials(host)
-		if err != nil {
-			return tokenOptions{}, err
-		}
-	}
-	return to, nil
-}
-
 // authResult is used to control limit rate.
 type authResult struct {
 	sync.WaitGroup
@@ -227,17 +199,17 @@ type authHandler struct {
 	client *http.Client
 
 	// only support basic and bearer schemes
-	scheme authenticationScheme
+	scheme auth.AuthenticationScheme
 
 	// common contains common challenge answer
-	common tokenOptions
+	common auth.TokenOptions
 
 	// scopedTokens caches token indexed by scopes, which used in
 	// bearer auth case
 	scopedTokens map[string]*authResult
 }
 
-func newAuthHandler(client *http.Client, hdr http.Header, scheme authenticationScheme, opts tokenOptions) *authHandler {
+func newAuthHandler(client *http.Client, hdr http.Header, scheme auth.AuthenticationScheme, opts auth.TokenOptions) *authHandler {
 	return &authHandler{
 		header:       hdr,
 		client:       client,
@@ -249,17 +221,17 @@ func newAuthHandler(client *http.Client, hdr http.Header, scheme authenticationS
 
 func (ah *authHandler) authorize(ctx context.Context) (string, error) {
 	switch ah.scheme {
-	case basicAuth:
+	case auth.BasicAuth:
 		return ah.doBasicAuth(ctx)
-	case bearerAuth:
+	case auth.BearerAuth:
 		return ah.doBearerAuth(ctx)
 	default:
-		return "", errors.Wrap(errdefs.ErrNotImplemented, "failed to find supported auth scheme")
+		return "", errors.Wrapf(errdefs.ErrNotImplemented, "failed to find supported auth scheme: %s", string(ah.scheme))
 	}
 }
 
 func (ah *authHandler) doBasicAuth(ctx context.Context) (string, error) {
-	username, secret := ah.common.username, ah.common.secret
+	username, secret := ah.common.Username, ah.common.Secret
 
 	if username == "" || secret == "" {
 		return "", fmt.Errorf("failed to handle basic auth because missing username or secret")
@@ -273,10 +245,10 @@ func (ah *authHandler) doBearerAuth(ctx context.Context) (string, error) {
 	// copy common tokenOptions
 	to := ah.common
 
-	to.scopes = GetTokenScopes(ctx, to.scopes)
+	to.Scopes = GetTokenScopes(ctx, to.Scopes)
 
 	// Docs: https://docs.docker.com/registry/spec/auth/scope
-	scoped := strings.Join(to.scopes, " ")
+	scoped := strings.Join(to.Scopes, " ")
 
 	ah.Lock()
 	if r, exist := ah.scopedTokens[scoped]; exist {
@@ -296,13 +268,30 @@ func (ah *authHandler) doBearerAuth(ctx context.Context) (string, error) {
 		token string
 		err   error
 	)
-	if to.secret != "" {
+	if to.Secret != "" {
 		// credential information is provided, use oauth POST endpoint
-		token, err = ah.fetchTokenWithOAuth(ctx, to)
+		// TODO: Allow setting client_id
+		token, err = auth.FetchTokenWithOAuth(ctx, ah.client, ah.header, "containerd-client", to)
+		if err != nil {
+			var errStatus auth.ErrUnexpectedStatus
+			if errors.As(err, &errStatus) {
+				// Registries without support for POST may return 404 for POST /v2/token.
+				// As of September 2017, GCR is known to return 404.
+				// As of February 2018, JFrog Artifactory is known to return 401.
+				if (errStatus.StatusCode == 405 && to.Username != "") || errStatus.StatusCode == 404 || errStatus.StatusCode == 401 {
+					token, err = auth.FetchToken(ctx, ah.client, ah.header, to)
+				} else {
+					log.G(ctx).WithFields(logrus.Fields{
+						"status": errStatus.Status,
+						"body":   string(errStatus.Body),
+					}).Debugf("token request failed")
+				}
+			}
+		}
 		err = errors.Wrap(err, "failed to fetch oauth token")
 	} else {
 		// do request anonymously
-		token, err = ah.fetchToken(ctx, to)
+		token, err = auth.FetchToken(ctx, ah.client, ah.header, to)
 		err = errors.Wrap(err, "failed to fetch anonymous token")
 	}
 	token = fmt.Sprintf("Bearer %s", token)
@@ -312,153 +301,8 @@ func (ah *authHandler) doBearerAuth(ctx context.Context) (string, error) {
 	return r.token, r.err
 }
 
-type tokenOptions struct {
+func invalidAuthorization(c auth.Challenge, responses []*http.Response) error {
-	realm    string
+	errStr := c.Parameters["error"]
-	service  string
-	scopes   []string
-	username string
-	secret   string
-}
-
-type postTokenResponse struct {
-	AccessToken  string    `json:"access_token"`
-	RefreshToken string    `json:"refresh_token"`
-	ExpiresIn    int       `json:"expires_in"`
-	IssuedAt     time.Time `json:"issued_at"`
-	Scope        string    `json:"scope"`
-}
-
-func (ah *authHandler) fetchTokenWithOAuth(ctx context.Context, to tokenOptions) (string, error) {
-	form := url.Values{}
-	if len(to.scopes) > 0 {
-		form.Set("scope", strings.Join(to.scopes, " "))
-	}
-	form.Set("service", to.service)
-	// TODO: Allow setting client_id
-	form.Set("client_id", "containerd-client")
-
-	if to.username == "" {
-		form.Set("grant_type", "refresh_token")
-		form.Set("refresh_token", to.secret)
-	} else {
-		form.Set("grant_type", "password")
-		form.Set("username", to.username)
-		form.Set("password", to.secret)
-	}
-
-	req, err := http.NewRequest("POST", to.realm, strings.NewReader(form.Encode()))
-	if err != nil {
-		return "", err
-	}
-	req.Header.Set("Content-Type", "application/x-www-form-urlencoded; charset=utf-8")
-	if ah.header != nil {
-		for k, v := range ah.header {
-			req.Header[k] = append(req.Header[k], v...)
-		}
-	}
-
-	resp, err := ctxhttp.Do(ctx, ah.client, req)
-	if err != nil {
-		return "", err
-	}
-	defer resp.Body.Close()
-
-	// Registries without support for POST may return 404 for POST /v2/token.
-	// As of September 2017, GCR is known to return 404.
-	// As of February 2018, JFrog Artifactory is known to return 401.
-	if (resp.StatusCode == 405 && to.username != "") || resp.StatusCode == 404 || resp.StatusCode == 401 {
-		return ah.fetchToken(ctx, to)
-	} else if resp.StatusCode < 200 || resp.StatusCode >= 400 {
-		b, _ := ioutil.ReadAll(io.LimitReader(resp.Body, 64000)) // 64KB
-		log.G(ctx).WithFields(logrus.Fields{
-			"status": resp.Status,
-			"body":   string(b),
-		}).Debugf("token request failed")
-		// TODO: handle error body and write debug output
-		return "", errors.Errorf("unexpected status: %s", resp.Status)
-	}
-
-	decoder := json.NewDecoder(resp.Body)
-
-	var tr postTokenResponse
-	if err = decoder.Decode(&tr); err != nil {
-		return "", fmt.Errorf("unable to decode token response: %s", err)
-	}
-
-	return tr.AccessToken, nil
-}
-
-type getTokenResponse struct {
-	Token        string    `json:"token"`
-	AccessToken  string    `json:"access_token"`
-	ExpiresIn    int       `json:"expires_in"`
-	IssuedAt     time.Time `json:"issued_at"`
-	RefreshToken string    `json:"refresh_token"`
-}
-
-// fetchToken fetches a token using a GET request
-func (ah *authHandler) fetchToken(ctx context.Context, to tokenOptions) (string, error) {
-	req, err := http.NewRequest("GET", to.realm, nil)
-	if err != nil {
-		return "", err
-	}
-
-	if ah.header != nil {
-		for k, v := range ah.header {
-			req.Header[k] = append(req.Header[k], v...)
-		}
-	}
-
-	reqParams := req.URL.Query()
-
-	if to.service != "" {
-		reqParams.Add("service", to.service)
-	}
-
-	for _, scope := range to.scopes {
-		reqParams.Add("scope", scope)
-	}
-
-	if to.secret != "" {
-		req.SetBasicAuth(to.username, to.secret)
-	}
-
-	req.URL.RawQuery = reqParams.Encode()
-
-	resp, err := ctxhttp.Do(ctx, ah.client, req)
-	if err != nil {
-		return "", err
-	}
-	defer resp.Body.Close()
-
-	if resp.StatusCode < 200 || resp.StatusCode >= 400 {
-		// TODO: handle error body and write debug output
-		return "", errors.Errorf("unexpected status: %s", resp.Status)
-	}
-
-	decoder := json.NewDecoder(resp.Body)
-
-	var tr getTokenResponse
-	if err = decoder.Decode(&tr); err != nil {
-		return "", fmt.Errorf("unable to decode token response: %s", err)
-	}
-
-	// `access_token` is equivalent to `token` and if both are specified
-	// the choice is undefined.  Canonicalize `access_token` by sticking
-	// things in `token`.
-	if tr.AccessToken != "" {
-		tr.Token = tr.AccessToken
-	}
-
-	if tr.Token == "" {
-		return "", ErrNoToken
-	}
-
-	return tr.Token, nil
-}
-
-func invalidAuthorization(c challenge, responses []*http.Response) error {
-	errStr := c.parameters["error"]
 	if errStr == "" {
 		return nil
 	}

remotes/docker/resolver.go

@@ -40,10 +40,6 @@ import (
 )
 
 var (
-	// ErrNoToken is returned if a request is successful but the body does not
-	// contain an authorization token.
-	ErrNoToken = errors.New("authorization server did not include a token in the response")
-
 	// ErrInvalidAuthorization is used when credentials are passed to a server but
 	// those credentials are rejected.
 	ErrInvalidAuthorization = errors.New("authorization failed")