docker-compose/azure/login/login.go

/*
   Copyright 2020 Docker, Inc.

   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 login

import (
	"context"
	"encoding/json"
	"fmt"
	"log"
	"net/http"
	"net/url"
	"os/exec"
	"path/filepath"
	"runtime"
	"strconv"
	"time"

	"github.com/Azure/go-autorest/autorest"
	"github.com/Azure/go-autorest/autorest/adal"
	"github.com/Azure/go-autorest/autorest/azure/cli"
	"github.com/Azure/go-autorest/autorest/date"
	"github.com/pkg/errors"
	"golang.org/x/oauth2"

	"github.com/docker/api/errdefs"
)

//go login process, derived from code sample provided by MS at https://github.com/devigned/go-az-cli-stuff
const (
	authorizeFormat  = "https://login.microsoftonline.com/organizations/oauth2/v2.0/authorize?response_type=code&client_id=%s&redirect_uri=%s&state=%s&prompt=select_account&response_mode=query&scope=%s"
	tokenEndpoint    = "https://login.microsoftonline.com/%s/oauth2/v2.0/token"
	authorizationURL = "https://management.azure.com/tenants?api-version=2019-11-01"
	// scopes for a multi-tenant app works for openid, email, other common scopes, but fails when trying to add a token
	// v1 scope like "https://management.azure.com/.default" for ARM access
	scopes   = "offline_access https://management.azure.com/.default"
	clientID = "04b07795-8ddb-461a-bbee-02f9e1bf7b46" // Azure CLI client id
)

type (
	azureToken struct {
		Type         string `json:"token_type"`
		Scope        string `json:"scope"`
		ExpiresIn    int    `json:"expires_in"`
		ExtExpiresIn int    `json:"ext_expires_in"`
		AccessToken  string `json:"access_token"`
		RefreshToken string `json:"refresh_token"`
		Foci         string `json:"foci"`
	}

	tenantResult struct {
		Value []tenantValue `json:"value"`
	}
	tenantValue struct {
		TenantID string `json:"tenantId"`
	}
)

// AzureLoginService Service to log into azure and get authentifier for azure APIs
type AzureLoginService struct {
	tokenStore tokenStore
	apiHelper  apiHelper
}

const tokenStoreFilename = "dockerAccessToken.json"

// NewAzureLoginService creates a NewAzureLoginService
func NewAzureLoginService() (AzureLoginService, error) {
	return newAzureLoginServiceFromPath(getTokenStorePath(), azureAPIHelper{})
}

func newAzureLoginServiceFromPath(tokenStorePath string, helper apiHelper) (AzureLoginService, error) {
	store, err := newTokenStore(tokenStorePath)
	if err != nil {
		return AzureLoginService{}, err
	}
	return AzureLoginService{
		tokenStore: store,
		apiHelper:  helper,
	}, nil
}

// Login performs an Azure login through a web browser
func (login AzureLoginService) Login(ctx context.Context) error {
	queryCh := make(chan localResponse, 1)
	s, err := NewLocalServer(queryCh)
	if err != nil {
		return err
	}
	s.Serve()
	defer s.Close()

	redirectURL := s.Addr()
	if redirectURL == "" {
		return errors.Wrap(errdefs.ErrLoginFailed, "empty redirect URL")
	}
	login.apiHelper.openAzureLoginPage(redirectURL)

	select {
	case <-ctx.Done():
		return ctx.Err()
	case q := <-queryCh:
		if q.err != nil {
			return errors.Wrapf(errdefs.ErrLoginFailed, "unhandled local login server error: %s", err)
		}
		code, hasCode := q.values["code"]
		if !hasCode {
			return errors.Wrap(errdefs.ErrLoginFailed, "no login code")
		}
		data := url.Values{
			"grant_type":   []string{"authorization_code"},
			"client_id":    []string{clientID},
			"code":         code,
			"scope":        []string{scopes},
			"redirect_uri": []string{redirectURL},
		}
		token, err := login.apiHelper.queryToken(data, "organizations")
		if err != nil {
			return errors.Wrapf(errdefs.ErrLoginFailed, "access token request failed: %s", err)
		}

		bits, statusCode, err := login.apiHelper.queryAuthorizationAPI(authorizationURL, fmt.Sprintf("Bearer %s", token.AccessToken))
		if err != nil {
			return errors.Wrapf(errdefs.ErrLoginFailed, "check auth failed: %s", err)
		}

		switch statusCode {
		case http.StatusOK:
			var t tenantResult
			if err := json.Unmarshal(bits, &t); err != nil {
				return errors.Wrapf(errdefs.ErrLoginFailed, "unable to unmarshal tenant: %s", err)
			}
			if len(t.Value) < 1 {
				return errors.Wrap(errdefs.ErrLoginFailed, "could not find azure tenant")
			}
			tID := t.Value[0].TenantID
			tToken, err := login.refreshToken(token.RefreshToken, tID)
			if err != nil {
				return errors.Wrapf(errdefs.ErrLoginFailed, "unable to refresh token: %s", err)
			}
			loginInfo := TokenInfo{TenantID: tID, Token: tToken}

			if err := login.tokenStore.writeLoginInfo(loginInfo); err != nil {
				return errors.Wrapf(errdefs.ErrLoginFailed, "could not store login info: %s", err)
			}
		default:
			return errors.Wrapf(errdefs.ErrLoginFailed, "unable to login status code %d: %s", statusCode, bits)
		}
	}
	return nil
}

func getTokenStorePath() string {
	cliPath, _ := cli.AccessTokensPath()
	return filepath.Join(filepath.Dir(cliPath), tokenStoreFilename)
}

func toOAuthToken(token azureToken) oauth2.Token {
	expireTime := time.Now().Add(time.Duration(token.ExpiresIn) * time.Second)
	oauthToken := oauth2.Token{
		RefreshToken: token.RefreshToken,
		AccessToken:  token.AccessToken,
		Expiry:       expireTime,
		TokenType:    token.Type,
	}
	return oauthToken
}

// NewAuthorizerFromLogin creates an authorizer based on login access token
func NewAuthorizerFromLogin() (autorest.Authorizer, error) {
	return newAuthorizerFromLoginStorePath(getTokenStorePath())
}

func newAuthorizerFromLoginStorePath(storeTokenPath string) (autorest.Authorizer, error) {
	login, err := newAzureLoginServiceFromPath(storeTokenPath, azureAPIHelper{})
	if err != nil {
		return nil, err
	}
	oauthToken, err := login.GetValidToken()
	if err != nil {
		return nil, errors.Wrap(err, "not logged in to azure, you need to run \"docker login azure\" first")
	}

	token := adal.Token{
		AccessToken:  oauthToken.AccessToken,
		Type:         oauthToken.TokenType,
		ExpiresIn:    json.Number(strconv.Itoa(int(time.Until(oauthToken.Expiry).Seconds()))),
		ExpiresOn:    json.Number(strconv.Itoa(int(oauthToken.Expiry.Sub(date.UnixEpoch()).Seconds()))),
		RefreshToken: "",
		Resource:     "",
	}

	return autorest.NewBearerAuthorizer(&token), nil
}

// GetValidToken returns an access token. Refresh token if needed
func (login AzureLoginService) GetValidToken() (oauth2.Token, error) {
	loginInfo, err := login.tokenStore.readToken()
	if err != nil {
		return oauth2.Token{}, err
	}
	token := loginInfo.Token
	if token.Valid() {
		return token, nil
	}
	tenantID := loginInfo.TenantID
	token, err = login.refreshToken(token.RefreshToken, tenantID)
	if err != nil {
		return oauth2.Token{}, errors.Wrap(err, "access token request failed. Maybe you need to login to azure again.")
	}
	err = login.tokenStore.writeLoginInfo(TokenInfo{TenantID: tenantID, Token: token})
	if err != nil {
		return oauth2.Token{}, err
	}
	return token, nil
}

func (login AzureLoginService) refreshToken(currentRefreshToken string, tenantID string) (oauth2.Token, error) {
	data := url.Values{
		"grant_type":    []string{"refresh_token"},
		"client_id":     []string{clientID},
		"scope":         []string{scopes},
		"refresh_token": []string{currentRefreshToken},
	}
	token, err := login.apiHelper.queryToken(data, tenantID)
	if err != nil {
		return oauth2.Token{}, err
	}

	return toOAuthToken(token), nil
}

func openbrowser(url string) {
	var err error

	switch runtime.GOOS {
	case "linux":
		err = exec.Command("xdg-open", url).Start()
	case "windows":
		err = exec.Command("rundll32", "url.dll,FileProtocolHandler", url).Start()
	case "darwin":
		err = exec.Command("open", url).Start()
	default:
		err = fmt.Errorf("unsupported platform")
	}
	if err != nil {
		log.Fatal(err)
	}
}