dex/connector/github/github.go

288 lines
7.3 KiB
Go

// Package github provides authentication strategies using GitHub.
package github
import (
"context"
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"net/http"
"regexp"
"strconv"
"golang.org/x/oauth2"
"golang.org/x/oauth2/github"
"github.com/Sirupsen/logrus"
"github.com/coreos/dex/connector"
)
const (
baseURL = "https://api.github.com"
scopeEmail = "user:email"
scopeOrgs = "read:org"
)
// Config holds configuration options for github logins.
type Config struct {
ClientID string `json:"clientID"`
ClientSecret string `json:"clientSecret"`
RedirectURI string `json:"redirectURI"`
Org string `json:"org"`
}
// Open returns a strategy for logging in through GitHub.
func (c *Config) Open(logger logrus.FieldLogger) (connector.Connector, error) {
return &githubConnector{
redirectURI: c.RedirectURI,
org: c.Org,
clientID: c.ClientID,
clientSecret: c.ClientSecret,
logger: logger,
}, nil
}
type connectorData struct {
// GitHub's OAuth2 tokens never expire. We don't need a refresh token.
AccessToken string `json:"accessToken"`
}
var (
_ connector.CallbackConnector = (*githubConnector)(nil)
_ connector.RefreshConnector = (*githubConnector)(nil)
)
type githubConnector struct {
redirectURI string
org string
clientID string
clientSecret string
logger logrus.FieldLogger
}
func (c *githubConnector) oauth2Config(scopes connector.Scopes) *oauth2.Config {
var githubScopes []string
if scopes.Groups {
githubScopes = []string{scopeEmail, scopeOrgs}
} else {
githubScopes = []string{scopeEmail}
}
return &oauth2.Config{
ClientID: c.clientID,
ClientSecret: c.clientSecret,
Endpoint: github.Endpoint,
Scopes: githubScopes,
}
}
func (c *githubConnector) LoginURL(scopes connector.Scopes, callbackURL, state string) (string, error) {
if c.redirectURI != callbackURL {
return "", fmt.Errorf("expected callback URL did not match the URL in the config")
}
return c.oauth2Config(scopes).AuthCodeURL(state), nil
}
type oauth2Error struct {
error string
errorDescription string
}
func (e *oauth2Error) Error() string {
if e.errorDescription == "" {
return e.error
}
return e.error + ": " + e.errorDescription
}
func (c *githubConnector) HandleCallback(s connector.Scopes, r *http.Request) (identity connector.Identity, err error) {
q := r.URL.Query()
if errType := q.Get("error"); errType != "" {
return identity, &oauth2Error{errType, q.Get("error_description")}
}
oauth2Config := c.oauth2Config(s)
ctx := r.Context()
token, err := oauth2Config.Exchange(ctx, q.Get("code"))
if err != nil {
return identity, fmt.Errorf("github: failed to get token: %v", err)
}
client := oauth2Config.Client(ctx, token)
user, err := c.user(ctx, client)
if err != nil {
return identity, fmt.Errorf("github: get user: %v", err)
}
username := user.Name
if username == "" {
username = user.Login
}
identity = connector.Identity{
UserID: strconv.Itoa(user.ID),
Username: username,
Email: user.Email,
EmailVerified: true,
}
if s.Groups && c.org != "" {
groups, err := c.teams(ctx, client, c.org)
if err != nil {
return identity, fmt.Errorf("github: get teams: %v", err)
}
identity.Groups = groups
}
if s.OfflineAccess {
data := connectorData{AccessToken: token.AccessToken}
connData, err := json.Marshal(data)
if err != nil {
return identity, fmt.Errorf("marshal connector data: %v", err)
}
identity.ConnectorData = connData
}
return identity, nil
}
func (c *githubConnector) Refresh(ctx context.Context, s connector.Scopes, ident connector.Identity) (connector.Identity, error) {
if len(ident.ConnectorData) == 0 {
return ident, errors.New("no upstream access token found")
}
var data connectorData
if err := json.Unmarshal(ident.ConnectorData, &data); err != nil {
return ident, fmt.Errorf("github: unmarshal access token: %v", err)
}
client := c.oauth2Config(s).Client(ctx, &oauth2.Token{AccessToken: data.AccessToken})
user, err := c.user(ctx, client)
if err != nil {
return ident, fmt.Errorf("github: get user: %v", err)
}
username := user.Name
if username == "" {
username = user.Login
}
ident.Username = username
ident.Email = user.Email
if s.Groups && c.org != "" {
groups, err := c.teams(ctx, client, c.org)
if err != nil {
return ident, fmt.Errorf("github: get teams: %v", err)
}
ident.Groups = groups
}
return ident, nil
}
type user struct {
Name string `json:"name"`
Login string `json:"login"`
ID int `json:"id"`
Email string `json:"email"`
}
// user queries the GitHub API for profile information using the provided client. The HTTP
// client is expected to be constructed by the golang.org/x/oauth2 package, which inserts
// a bearer token as part of the request.
func (c *githubConnector) user(ctx context.Context, client *http.Client) (user, error) {
var u user
req, err := http.NewRequest("GET", baseURL+"/user", nil)
if err != nil {
return u, fmt.Errorf("github: new req: %v", err)
}
req = req.WithContext(ctx)
resp, err := client.Do(req)
if err != nil {
return u, fmt.Errorf("github: get URL %v", err)
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return u, fmt.Errorf("github: read body: %v", err)
}
return u, fmt.Errorf("%s: %s", resp.Status, body)
}
if err := json.NewDecoder(resp.Body).Decode(&u); err != nil {
return u, fmt.Errorf("failed to decode response: %v", err)
}
return u, nil
}
// teams queries the GitHub API for team membership within a specific organization.
//
// The HTTP passed client is expected to be constructed by the golang.org/x/oauth2 package,
// which inserts a bearer token as part of the request.
func (c *githubConnector) teams(ctx context.Context, client *http.Client, org string) ([]string, error) {
groups := []string{}
// https://developer.github.com/v3/#pagination
reNext := regexp.MustCompile("<(.*)>; rel=\"next\"")
reLast := regexp.MustCompile("<(.*)>; rel=\"last\"")
apiURL := baseURL + "/user/teams"
for {
req, err := http.NewRequest("GET", apiURL, nil)
if err != nil {
return nil, fmt.Errorf("github: new req: %v", err)
}
req = req.WithContext(ctx)
resp, err := client.Do(req)
if err != nil {
return nil, fmt.Errorf("github: get teams: %v", err)
}
defer resp.Body.Close()
if resp.StatusCode != http.StatusOK {
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, fmt.Errorf("github: read body: %v", err)
}
return nil, fmt.Errorf("%s: %s", resp.Status, body)
}
// https://developer.github.com/v3/orgs/teams/#response-12
var teams []struct {
Name string `json:"name"`
Org struct {
Login string `json:"login"`
} `json:"organization"`
}
if err := json.NewDecoder(resp.Body).Decode(&teams); err != nil {
return nil, fmt.Errorf("github: unmarshal groups: %v", err)
}
for _, team := range teams {
if team.Org.Login == org {
groups = append(groups, team.Name)
}
}
links := resp.Header.Get("Link")
if len(reLast.FindStringSubmatch(links)) > 1 {
lastPageURL := reLast.FindStringSubmatch(links)[1]
if apiURL == lastPageURL {
break
}
} else {
break
}
if len(reNext.FindStringSubmatch(links)) > 1 {
apiURL = reNext.FindStringSubmatch(links)[1]
} else {
break
}
}
return groups, nil
}