A simple, federated blogging platform. Written in Go. Fork by @gytisrepecka to provide suggestions and fixes to upstream @writeas.
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/*
* Copyright © 2019-2020 A Bunch Tell LLC.
*
* This file is part of WriteFreely.
*
* WriteFreely is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, included
* in the LICENSE file in this source code package.
*/
package writefreely
import (
"context"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"strings"
"time"
"github.com/gorilla/mux"
"github.com/gorilla/sessions"
"github.com/writeas/impart"
"github.com/writeas/web-core/log"
"github.com/writeas/writefreely/config"
)
// OAuthButtons holds display information for different OAuth providers we support.
type OAuthButtons struct {
SlackEnabled bool
WriteAsEnabled bool
GitLabEnabled bool
GitLabDisplayName string
}
// NewOAuthButtons creates a new OAuthButtons struct based on our app configuration.
func NewOAuthButtons(cfg *config.Config) *OAuthButtons {
return &OAuthButtons{
SlackEnabled: cfg.SlackOauth.ClientID != "",
WriteAsEnabled: cfg.WriteAsOauth.ClientID != "",
GitLabEnabled: cfg.GitlabOauth.ClientID != "",
GitLabDisplayName: config.OrDefaultString(cfg.GitlabOauth.DisplayName, gitlabDisplayName),
}
}
// TokenResponse contains data returned when a token is created either
// through a code exchange or using a refresh token.
type TokenResponse struct {
AccessToken string `json:"access_token"`
ExpiresIn int `json:"expires_in"`
RefreshToken string `json:"refresh_token"`
TokenType string `json:"token_type"`
Error string `json:"error"`
}
// InspectResponse contains data returned when an access token is inspected.
type InspectResponse struct {
ClientID string `json:"client_id"`
UserID string `json:"user_id"`
ExpiresAt time.Time `json:"expires_at"`
Username string `json:"username"`
DisplayName string `json:"-"`
Email string `json:"email"`
Error string `json:"error"`
}
// tokenRequestMaxLen is the most bytes that we'll read from the /oauth/token
// endpoint. One megabyte is plenty.
const tokenRequestMaxLen = 1000000
// infoRequestMaxLen is the most bytes that we'll read from the
// /oauth/inspect endpoint.
const infoRequestMaxLen = 1000000
// OAuthDatastoreProvider provides a minimal interface of data store, config,
// and session store for use with the oauth handlers.
type OAuthDatastoreProvider interface {
DB() OAuthDatastore
Config() *config.Config
SessionStore() sessions.Store
}
// OAuthDatastore provides a minimal interface of data store methods used in
// oauth functionality.
type OAuthDatastore interface {
GetIDForRemoteUser(context.Context, string, string, string) (int64, error)
RecordRemoteUserID(context.Context, int64, string, string, string, string) error
ValidateOAuthState(context.Context, string) (string, string, int64, string, error)
GenerateOAuthState(context.Context, string, string, int64, string) (string, error)
CreateUser(*config.Config, *User, string) error
GetUserByID(int64) (*User, error)
}
type HttpClient interface {
Do(req *http.Request) (*http.Response, error)
}
type oauthClient interface {
GetProvider() string
GetClientID() string
GetCallbackLocation() string
buildLoginURL(state string) (string, error)
exchangeOauthCode(ctx context.Context, code string) (*TokenResponse, error)
inspectOauthAccessToken(ctx context.Context, accessToken string) (*InspectResponse, error)
}
type callbackProxyClient struct {
server string
callbackLocation string
httpClient HttpClient
}
type oauthHandler struct {
Config *config.Config
DB OAuthDatastore
Store sessions.Store
EmailKey []byte
oauthClient oauthClient
callbackProxy *callbackProxyClient
}
func (h oauthHandler) viewOauthInit(app *App, w http.ResponseWriter, r *http.Request) error {
ctx := r.Context()
var attachUser int64
if attach := r.URL.Query().Get("attach"); attach == "t" {
user, _ := getUserAndSession(app, r)
if user == nil {
return impart.HTTPError{http.StatusInternalServerError, "cannot attach auth to user: user not found in session"}
}
attachUser = user.ID
}
state, err := h.DB.GenerateOAuthState(ctx, h.oauthClient.GetProvider(), h.oauthClient.GetClientID(), attachUser, r.FormValue("invite_code"))
if err != nil {
log.Error("viewOauthInit error: %s", err)
return impart.HTTPError{http.StatusInternalServerError, "could not prepare oauth redirect url"}
}
if h.callbackProxy != nil {
if err := h.callbackProxy.register(ctx, state); err != nil {
log.Error("viewOauthInit error: %s", err)
return impart.HTTPError{http.StatusInternalServerError, "could not register state server"}
}
}
location, err := h.oauthClient.buildLoginURL(state)
if err != nil {
log.Error("viewOauthInit error: %s", err)
return impart.HTTPError{http.StatusInternalServerError, "could not prepare oauth redirect url"}
}
return impart.HTTPError{http.StatusTemporaryRedirect, location}
}
func configureSlackOauth(parentHandler *Handler, r *mux.Router, app *App) {
if app.Config().SlackOauth.ClientID != "" {
callbackLocation := app.Config().App.Host + "/oauth/callback/slack"
var stateRegisterClient *callbackProxyClient = nil
if app.Config().SlackOauth.CallbackProxyAPI != "" {
stateRegisterClient = &callbackProxyClient{
server: app.Config().SlackOauth.CallbackProxyAPI,
callbackLocation: app.Config().App.Host + "/oauth/callback/slack",
httpClient: config.DefaultHTTPClient(),
}
callbackLocation = app.Config().SlackOauth.CallbackProxy
}
oauthClient := slackOauthClient{
ClientID: app.Config().SlackOauth.ClientID,
ClientSecret: app.Config().SlackOauth.ClientSecret,
TeamID: app.Config().SlackOauth.TeamID,
HttpClient: config.DefaultHTTPClient(),
CallbackLocation: callbackLocation,
}
configureOauthRoutes(parentHandler, r, app, oauthClient, stateRegisterClient)
}
}
func configureWriteAsOauth(parentHandler *Handler, r *mux.Router, app *App) {
if app.Config().WriteAsOauth.ClientID != "" {
callbackLocation := app.Config().App.Host + "/oauth/callback/write.as"
var callbackProxy *callbackProxyClient = nil
if app.Config().WriteAsOauth.CallbackProxy != "" {
callbackProxy = &callbackProxyClient{
server: app.Config().WriteAsOauth.CallbackProxyAPI,
callbackLocation: app.Config().App.Host + "/oauth/callback/write.as",
httpClient: config.DefaultHTTPClient(),
}
callbackLocation = app.Config().WriteAsOauth.CallbackProxy
}
oauthClient := writeAsOauthClient{
ClientID: app.Config().WriteAsOauth.ClientID,
ClientSecret: app.Config().WriteAsOauth.ClientSecret,
ExchangeLocation: config.OrDefaultString(app.Config().WriteAsOauth.TokenLocation, writeAsExchangeLocation),
InspectLocation: config.OrDefaultString(app.Config().WriteAsOauth.InspectLocation, writeAsIdentityLocation),
AuthLocation: config.OrDefaultString(app.Config().WriteAsOauth.AuthLocation, writeAsAuthLocation),
HttpClient: config.DefaultHTTPClient(),
CallbackLocation: callbackLocation,
}
configureOauthRoutes(parentHandler, r, app, oauthClient, callbackProxy)
}
}
func configureGitlabOauth(parentHandler *Handler, r *mux.Router, app *App) {
if app.Config().GitlabOauth.ClientID != "" {
callbackLocation := app.Config().App.Host + "/oauth/callback/gitlab"
var callbackProxy *callbackProxyClient = nil
if app.Config().GitlabOauth.CallbackProxy != "" {
callbackProxy = &callbackProxyClient{
server: app.Config().GitlabOauth.CallbackProxyAPI,
callbackLocation: app.Config().App.Host + "/oauth/callback/gitlab",
httpClient: config.DefaultHTTPClient(),
}
callbackLocation = app.Config().GitlabOauth.CallbackProxy
}
address := config.OrDefaultString(app.Config().GitlabOauth.Host, gitlabHost)
oauthClient := gitlabOauthClient{
ClientID: app.Config().GitlabOauth.ClientID,
ClientSecret: app.Config().GitlabOauth.ClientSecret,
ExchangeLocation: address + "/oauth/token",
InspectLocation: address + "/api/v4/user",
AuthLocation: address + "/oauth/authorize",
HttpClient: config.DefaultHTTPClient(),
CallbackLocation: callbackLocation,
}
configureOauthRoutes(parentHandler, r, app, oauthClient, callbackProxy)
}
}
func configureOauthRoutes(parentHandler *Handler, r *mux.Router, app *App, oauthClient oauthClient, callbackProxy *callbackProxyClient) {
handler := &oauthHandler{
Config: app.Config(),
DB: app.DB(),
Store: app.SessionStore(),
oauthClient: oauthClient,
EmailKey: app.keys.EmailKey,
callbackProxy: callbackProxy,
}
r.HandleFunc("/oauth/"+oauthClient.GetProvider(), parentHandler.OAuth(handler.viewOauthInit)).Methods("GET")
r.HandleFunc("/oauth/callback/"+oauthClient.GetProvider(), parentHandler.OAuth(handler.viewOauthCallback)).Methods("GET")
r.HandleFunc("/oauth/signup", parentHandler.OAuth(handler.viewOauthSignup)).Methods("POST")
}
func (h oauthHandler) viewOauthCallback(app *App, w http.ResponseWriter, r *http.Request) error {
ctx := r.Context()
code := r.FormValue("code")
state := r.FormValue("state")
provider, clientID, attachUserID, inviteCode, err := h.DB.ValidateOAuthState(ctx, state)
if err != nil {
log.Error("Unable to ValidateOAuthState: %s", err)
return impart.HTTPError{http.StatusInternalServerError, err.Error()}
}
tokenResponse, err := h.oauthClient.exchangeOauthCode(ctx, code)
if err != nil {
log.Error("Unable to exchangeOauthCode: %s", err)
return impart.HTTPError{http.StatusInternalServerError, err.Error()}
}
// Now that we have the access token, let's use it real quick to make sure
// it really really works.
tokenInfo, err := h.oauthClient.inspectOauthAccessToken(ctx, tokenResponse.AccessToken)
if err != nil {
log.Error("Unable to inspectOauthAccessToken: %s", err)
return impart.HTTPError{http.StatusInternalServerError, err.Error()}
}
localUserID, err := h.DB.GetIDForRemoteUser(ctx, tokenInfo.UserID, provider, clientID)
if err != nil {
log.Error("Unable to GetIDForRemoteUser: %s", err)
return impart.HTTPError{http.StatusInternalServerError, err.Error()}
}
if localUserID != -1 && attachUserID > 0 {
if err = addSessionFlash(app, w, r, "This Slack account is already attached to another user.", nil); err != nil {
return impart.HTTPError{Status: http.StatusInternalServerError, Message: err.Error()}
}
return impart.HTTPError{http.StatusFound, "/me/settings"}
}
if localUserID != -1 {
// Existing user, so log in now
user, err := h.DB.GetUserByID(localUserID)
if err != nil {
log.Error("Unable to GetUserByID %d: %s", localUserID, err)
return impart.HTTPError{http.StatusInternalServerError, err.Error()}
}
if err = loginOrFail(h.Store, w, r, user); err != nil {
log.Error("Unable to loginOrFail %d: %s", localUserID, err)
return impart.HTTPError{http.StatusInternalServerError, err.Error()}
}
return nil
}
if attachUserID > 0 {
log.Info("attaching to user %d", attachUserID)
err = h.DB.RecordRemoteUserID(r.Context(), attachUserID, tokenInfo.UserID, provider, clientID, tokenResponse.AccessToken)
if err != nil {
return impart.HTTPError{http.StatusInternalServerError, err.Error()}
}
return impart.HTTPError{http.StatusFound, "/me/settings"}
}
// New user registration below.
// First, verify that user is allowed to register
if inviteCode != "" {
// Verify invite code is valid
i, err := app.db.GetUserInvite(inviteCode)
if err != nil {
return impart.HTTPError{http.StatusInternalServerError, err.Error()}
}
if !i.Active(app.db) {
return impart.HTTPError{http.StatusNotFound, "Invite link has expired."}
}
} else if !app.cfg.App.OpenRegistration {
addSessionFlash(app, w, r, ErrUserNotFound.Error(), nil)
return impart.HTTPError{http.StatusFound, "/login"}
}
displayName := tokenInfo.DisplayName
if len(displayName) == 0 {
displayName = tokenInfo.Username
}
tp := &oauthSignupPageParams{
AccessToken: tokenResponse.AccessToken,
TokenUsername: tokenInfo.Username,
TokenAlias: tokenInfo.DisplayName,
TokenEmail: tokenInfo.Email,
TokenRemoteUser: tokenInfo.UserID,
Provider: provider,
ClientID: clientID,
InviteCode: inviteCode,
}
tp.TokenHash = tp.HashTokenParams(h.Config.Server.HashSeed)
return h.showOauthSignupPage(app, w, r, tp, nil)
}
func (r *callbackProxyClient) register(ctx context.Context, state string) error {
form := url.Values{}
form.Add("state", state)
form.Add("location", r.callbackLocation)
req, err := http.NewRequestWithContext(ctx, "POST", r.server, strings.NewReader(form.Encode()))
if err != nil {
return err
}
req.Header.Set("User-Agent", "writefreely")
req.Header.Set("Accept", "application/json")
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
resp, err := r.httpClient.Do(req)
if err != nil {
return err
}
if resp.StatusCode != http.StatusCreated {
return fmt.Errorf("unable register state location: %d", resp.StatusCode)
}
return nil
}
func limitedJsonUnmarshal(body io.ReadCloser, n int, thing interface{}) error {
lr := io.LimitReader(body, int64(n+1))
data, err := ioutil.ReadAll(lr)
if err != nil {
return err
}
if len(data) == n+1 {
return fmt.Errorf("content larger than max read allowance: %d", n)
}
return json.Unmarshal(data, thing)
}
func loginOrFail(store sessions.Store, w http.ResponseWriter, r *http.Request, user *User) error {
// An error may be returned, but a valid session should always be returned.
session, _ := store.Get(r, cookieName)
session.Values[cookieUserVal] = user.Cookie()
if err := session.Save(r, w); err != nil {
fmt.Println("error saving session", err)
return err
}
http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
return nil
}