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oauthproxy.go
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oauthproxy.go
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package main
import (
b64 "encoding/base64"
"errors"
"fmt"
"html/template"
"log"
"net"
"net/http"
"net/http/httputil"
"net/url"
"regexp"
"strings"
"time"
"github.com/mbland/hmacauth"
"github.com/pusher/oauth2_proxy/cookie"
"github.com/pusher/oauth2_proxy/providers"
"github.com/yhat/wsutil"
)
const (
// SignatureHeader is the name of the request header containing the GAP Signature
// Part of hmacauth
SignatureHeader = "GAP-Signature"
httpScheme = "http"
httpsScheme = "https"
// Cookies are limited to 4kb including the length of the cookie name,
// the cookie name can be up to 256 bytes
maxCookieLength = 3840
applicationJSON = "application/json"
)
// SignatureHeaders contains the headers to be signed by the hmac algorithm
// Part of hmacauth
var SignatureHeaders = []string{
"Content-Length",
"Content-Md5",
"Content-Type",
"Date",
"Authorization",
"X-Forwarded-User",
"X-Forwarded-Email",
"X-Forwarded-Access-Token",
"Cookie",
"Gap-Auth",
}
// OAuthProxy is the main authentication proxy
type OAuthProxy struct {
CookieSeed string
CookieName string
CSRFCookieName string
CookieDomain string
CookiePath string
CookieSecure bool
CookieHTTPOnly bool
CookieExpire time.Duration
CookieRefresh time.Duration
Validator func(string) bool
RobotsPath string
PingPath string
SignInPath string
SignOutPath string
OAuthStartPath string
OAuthCallbackPath string
AuthOnlyPath string
redirectURL *url.URL // the url to receive requests at
whitelistDomains []string
provider providers.Provider
ProxyPrefix string
SignInMessage string
HtpasswdFile *HtpasswdFile
DisplayHtpasswdForm bool
serveMux http.Handler
SetXAuthRequest bool
PassBasicAuth bool
SkipProviderButton bool
PassUserHeaders bool
BasicAuthPassword string
PassAccessToken bool
SetAuthorization bool
PassAuthorization bool
CookieCipher *cookie.Cipher
skipAuthRegex []string
skipAuthPreflight bool
compiledRegex []*regexp.Regexp
templates *template.Template
Footer string
}
// UpstreamProxy represents an upstream server to proxy to
type UpstreamProxy struct {
upstream string
handler http.Handler
wsHandler http.Handler
auth hmacauth.HmacAuth
}
// ServeHTTP proxies requests to the upstream provider while signing the
// request headers
func (u *UpstreamProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
w.Header().Set("GAP-Upstream-Address", u.upstream)
if u.auth != nil {
r.Header.Set("GAP-Auth", w.Header().Get("GAP-Auth"))
u.auth.SignRequest(r)
}
if u.wsHandler != nil && strings.ToLower(r.Header.Get("Connection")) == "upgrade" && r.Header.Get("Upgrade") == "websocket" {
u.wsHandler.ServeHTTP(w, r)
} else {
u.handler.ServeHTTP(w, r)
}
}
// NewReverseProxy creates a new reverse proxy for proxying requests to upstream
// servers
func NewReverseProxy(target *url.URL, flushInterval time.Duration) (proxy *httputil.ReverseProxy) {
proxy = httputil.NewSingleHostReverseProxy(target)
proxy.FlushInterval = flushInterval
return proxy
}
func setProxyUpstreamHostHeader(proxy *httputil.ReverseProxy, target *url.URL) {
director := proxy.Director
proxy.Director = func(req *http.Request) {
director(req)
// use RequestURI so that we aren't unescaping encoded slashes in the request path
req.Host = target.Host
req.URL.Opaque = req.RequestURI
req.URL.RawQuery = ""
}
}
func setProxyDirector(proxy *httputil.ReverseProxy) {
director := proxy.Director
proxy.Director = func(req *http.Request) {
director(req)
// use RequestURI so that we aren't unescaping encoded slashes in the request path
req.URL.Opaque = req.RequestURI
req.URL.RawQuery = ""
}
}
// NewFileServer creates a http.Handler to serve files from the filesystem
func NewFileServer(path string, filesystemPath string) (proxy http.Handler) {
return http.StripPrefix(path, http.FileServer(http.Dir(filesystemPath)))
}
// NewWebSocketOrRestReverseProxy creates a reverse proxy for REST or websocket based on url
func NewWebSocketOrRestReverseProxy(u *url.URL, opts *Options, auth hmacauth.HmacAuth) (restProxy http.Handler) {
u.Path = ""
proxy := NewReverseProxy(u, opts.FlushInterval)
if !opts.PassHostHeader {
setProxyUpstreamHostHeader(proxy, u)
} else {
setProxyDirector(proxy)
}
// this should give us a wss:// scheme if the url is https:// based.
var wsProxy *wsutil.ReverseProxy
if opts.ProxyWebSockets {
wsScheme := "ws" + strings.TrimPrefix(u.Scheme, "http")
wsURL := &url.URL{Scheme: wsScheme, Host: u.Host}
wsProxy = wsutil.NewSingleHostReverseProxy(wsURL)
}
return &UpstreamProxy{u.Host, proxy, wsProxy, auth}
}
// NewOAuthProxy creates a new instance of OOuthProxy from the options provided
func NewOAuthProxy(opts *Options, validator func(string) bool) *OAuthProxy {
serveMux := http.NewServeMux()
var auth hmacauth.HmacAuth
if sigData := opts.signatureData; sigData != nil {
auth = hmacauth.NewHmacAuth(sigData.hash, []byte(sigData.key),
SignatureHeader, SignatureHeaders)
}
for _, u := range opts.proxyURLs {
path := u.Path
switch u.Scheme {
case httpScheme, httpsScheme:
log.Printf("mapping path %q => upstream %q", path, u)
proxy := NewWebSocketOrRestReverseProxy(u, opts, auth)
serveMux.Handle(path, proxy)
case "file":
if u.Fragment != "" {
path = u.Fragment
}
log.Printf("mapping path %q => file system %q", path, u.Path)
proxy := NewFileServer(path, u.Path)
serveMux.Handle(path, &UpstreamProxy{path, proxy, nil, nil})
default:
panic(fmt.Sprintf("unknown upstream protocol %s", u.Scheme))
}
}
for _, u := range opts.CompiledRegex {
log.Printf("compiled skip-auth-regex => %q", u)
}
redirectURL := opts.redirectURL
if redirectURL.Path == "" {
redirectURL.Path = fmt.Sprintf("%s/callback", opts.ProxyPrefix)
}
log.Printf("OAuthProxy configured for %s Client ID: %s", opts.provider.Data().ProviderName, opts.ClientID)
refresh := "disabled"
if opts.CookieRefresh != time.Duration(0) {
refresh = fmt.Sprintf("after %s", opts.CookieRefresh)
}
log.Printf("Cookie settings: name:%s secure(https):%v httponly:%v expiry:%s domain:%s path:%s refresh:%s", opts.CookieName, opts.CookieSecure, opts.CookieHTTPOnly, opts.CookieExpire, opts.CookieDomain, opts.CookiePath, refresh)
var cipher *cookie.Cipher
if opts.PassAccessToken || opts.SetAuthorization || opts.PassAuthorization || (opts.CookieRefresh != time.Duration(0)) {
var err error
cipher, err = cookie.NewCipher(secretBytes(opts.CookieSecret))
if err != nil {
log.Fatal("cookie-secret error: ", err)
}
}
return &OAuthProxy{
CookieName: opts.CookieName,
CSRFCookieName: fmt.Sprintf("%v_%v", opts.CookieName, "csrf"),
CookieSeed: opts.CookieSecret,
CookieDomain: opts.CookieDomain,
CookiePath: opts.CookiePath,
CookieSecure: opts.CookieSecure,
CookieHTTPOnly: opts.CookieHTTPOnly,
CookieExpire: opts.CookieExpire,
CookieRefresh: opts.CookieRefresh,
Validator: validator,
RobotsPath: "/robots.txt",
PingPath: "/ping",
SignInPath: fmt.Sprintf("%s/sign_in", opts.ProxyPrefix),
SignOutPath: fmt.Sprintf("%s/sign_out", opts.ProxyPrefix),
OAuthStartPath: fmt.Sprintf("%s/start", opts.ProxyPrefix),
OAuthCallbackPath: fmt.Sprintf("%s/callback", opts.ProxyPrefix),
AuthOnlyPath: fmt.Sprintf("%s/auth", opts.ProxyPrefix),
ProxyPrefix: opts.ProxyPrefix,
provider: opts.provider,
serveMux: serveMux,
redirectURL: redirectURL,
whitelistDomains: opts.WhitelistDomains,
skipAuthRegex: opts.SkipAuthRegex,
skipAuthPreflight: opts.SkipAuthPreflight,
compiledRegex: opts.CompiledRegex,
SetXAuthRequest: opts.SetXAuthRequest,
PassBasicAuth: opts.PassBasicAuth,
PassUserHeaders: opts.PassUserHeaders,
BasicAuthPassword: opts.BasicAuthPassword,
PassAccessToken: opts.PassAccessToken,
SetAuthorization: opts.SetAuthorization,
PassAuthorization: opts.PassAuthorization,
SkipProviderButton: opts.SkipProviderButton,
CookieCipher: cipher,
templates: loadTemplates(opts.CustomTemplatesDir),
Footer: opts.Footer,
}
}
// GetRedirectURI returns the redirectURL that the upstream OAuth Provider will
// redirect clients to once authenticated
func (p *OAuthProxy) GetRedirectURI(host string) string {
// default to the request Host if not set
if p.redirectURL.Host != "" {
return p.redirectURL.String()
}
var u url.URL
u = *p.redirectURL
if u.Scheme == "" {
if p.CookieSecure {
u.Scheme = httpsScheme
} else {
u.Scheme = httpScheme
}
}
u.Host = host
return u.String()
}
func (p *OAuthProxy) displayCustomLoginForm() bool {
return p.HtpasswdFile != nil && p.DisplayHtpasswdForm
}
func (p *OAuthProxy) redeemCode(host, code string) (s *providers.SessionState, err error) {
if code == "" {
return nil, errors.New("missing code")
}
redirectURI := p.GetRedirectURI(host)
s, err = p.provider.Redeem(redirectURI, code)
if err != nil {
return
}
if s.Email == "" {
s.Email, err = p.provider.GetEmailAddress(s)
}
if s.User == "" {
s.User, err = p.provider.GetUserName(s)
if err != nil && err.Error() == "not implemented" {
err = nil
}
}
return
}
// MakeSessionCookie creates an http.Cookie containing the authenticated user's
// authentication details
func (p *OAuthProxy) MakeSessionCookie(req *http.Request, value string, expiration time.Duration, now time.Time) []*http.Cookie {
if value != "" {
value = cookie.SignedValue(p.CookieSeed, p.CookieName, value, now)
}
c := p.makeCookie(req, p.CookieName, value, expiration, now)
if len(c.Value) > 4096-len(p.CookieName) {
return splitCookie(c)
}
return []*http.Cookie{c}
}
func copyCookie(c *http.Cookie) *http.Cookie {
return &http.Cookie{
Name: c.Name,
Value: c.Value,
Path: c.Path,
Domain: c.Domain,
Expires: c.Expires,
RawExpires: c.RawExpires,
MaxAge: c.MaxAge,
Secure: c.Secure,
HttpOnly: c.HttpOnly,
Raw: c.Raw,
Unparsed: c.Unparsed,
}
}
// splitCookie reads the full cookie generated to store the session and splits
// it into a slice of cookies which fit within the 4kb cookie limit indexing
// the cookies from 0
func splitCookie(c *http.Cookie) []*http.Cookie {
if len(c.Value) < maxCookieLength {
return []*http.Cookie{c}
}
cookies := []*http.Cookie{}
valueBytes := []byte(c.Value)
count := 0
for len(valueBytes) > 0 {
new := copyCookie(c)
new.Name = fmt.Sprintf("%s_%d", c.Name, count)
count++
if len(valueBytes) < maxCookieLength {
new.Value = string(valueBytes)
valueBytes = []byte{}
} else {
newValue := valueBytes[:maxCookieLength]
valueBytes = valueBytes[maxCookieLength:]
new.Value = string(newValue)
}
cookies = append(cookies, new)
}
return cookies
}
// joinCookies takes a slice of cookies from the request and reconstructs the
// full session cookie
func joinCookies(cookies []*http.Cookie) (*http.Cookie, error) {
if len(cookies) == 0 {
return nil, fmt.Errorf("list of cookies must be > 0")
}
if len(cookies) == 1 {
return cookies[0], nil
}
c := copyCookie(cookies[0])
for i := 1; i < len(cookies); i++ {
c.Value += cookies[i].Value
}
c.Name = strings.TrimRight(c.Name, "_0")
return c, nil
}
// loadCookie retreieves the sessions state cookie from the http request.
// If a single cookie is present this will be returned, otherwise it attempts
// to reconstruct a cookie split up by splitCookie
func loadCookie(req *http.Request, cookieName string) (*http.Cookie, error) {
c, err := req.Cookie(cookieName)
if err == nil {
return c, nil
}
cookies := []*http.Cookie{}
err = nil
count := 0
for err == nil {
var c *http.Cookie
c, err = req.Cookie(fmt.Sprintf("%s_%d", cookieName, count))
if err == nil {
cookies = append(cookies, c)
count++
}
}
if len(cookies) == 0 {
return nil, fmt.Errorf("Could not find cookie %s", cookieName)
}
return joinCookies(cookies)
}
// MakeCSRFCookie creates a cookie for CSRF
func (p *OAuthProxy) MakeCSRFCookie(req *http.Request, value string, expiration time.Duration, now time.Time) *http.Cookie {
return p.makeCookie(req, p.CSRFCookieName, value, expiration, now)
}
func (p *OAuthProxy) makeCookie(req *http.Request, name string, value string, expiration time.Duration, now time.Time) *http.Cookie {
if p.CookieDomain != "" {
domain := req.Host
if h, _, err := net.SplitHostPort(domain); err == nil {
domain = h
}
if !strings.HasSuffix(domain, p.CookieDomain) {
log.Printf("Warning: request host is %q but using configured cookie domain of %q", domain, p.CookieDomain)
}
}
return &http.Cookie{
Name: name,
Value: value,
Path: p.CookiePath,
Domain: p.CookieDomain,
HttpOnly: p.CookieHTTPOnly,
Secure: p.CookieSecure,
Expires: now.Add(expiration),
}
}
// ClearCSRFCookie creates a cookie to unset the CSRF cookie stored in the user's
// session
func (p *OAuthProxy) ClearCSRFCookie(rw http.ResponseWriter, req *http.Request) {
http.SetCookie(rw, p.MakeCSRFCookie(req, "", time.Hour*-1, time.Now()))
}
// SetCSRFCookie adds a CSRF cookie to the response
func (p *OAuthProxy) SetCSRFCookie(rw http.ResponseWriter, req *http.Request, val string) {
http.SetCookie(rw, p.MakeCSRFCookie(req, val, p.CookieExpire, time.Now()))
}
// ClearSessionCookie creates a cookie to unset the user's authentication cookie
// stored in the user's session
func (p *OAuthProxy) ClearSessionCookie(rw http.ResponseWriter, req *http.Request) {
var cookies []*http.Cookie
// matches CookieName, CookieName_<number>
var cookieNameRegex = regexp.MustCompile(fmt.Sprintf("^%s(_\\d+)?$", p.CookieName))
for _, c := range req.Cookies() {
if cookieNameRegex.MatchString(c.Name) {
clearCookie := p.makeCookie(req, c.Name, "", time.Hour*-1, time.Now())
http.SetCookie(rw, clearCookie)
cookies = append(cookies, clearCookie)
}
}
// ugly hack because default domain changed
if p.CookieDomain == "" && len(cookies) > 0 {
clr2 := *cookies[0]
clr2.Domain = req.Host
http.SetCookie(rw, &clr2)
}
}
// SetSessionCookie adds the user's session cookie to the response
func (p *OAuthProxy) SetSessionCookie(rw http.ResponseWriter, req *http.Request, val string) {
for _, c := range p.MakeSessionCookie(req, val, p.CookieExpire, time.Now()) {
http.SetCookie(rw, c)
}
}
// LoadCookiedSession reads the user's authentication details from the request
func (p *OAuthProxy) LoadCookiedSession(req *http.Request) (*providers.SessionState, time.Duration, error) {
var age time.Duration
c, err := loadCookie(req, p.CookieName)
if err != nil {
// always http.ErrNoCookie
return nil, age, fmt.Errorf("Cookie %q not present", p.CookieName)
}
val, timestamp, ok := cookie.Validate(c, p.CookieSeed, p.CookieExpire)
if !ok {
return nil, age, errors.New("Cookie Signature not valid")
}
session, err := p.provider.SessionFromCookie(val, p.CookieCipher)
if err != nil {
return nil, age, err
}
age = time.Now().Truncate(time.Second).Sub(timestamp)
return session, age, nil
}
// SaveSession creates a new session cookie value and sets this on the response
func (p *OAuthProxy) SaveSession(rw http.ResponseWriter, req *http.Request, s *providers.SessionState) error {
value, err := p.provider.CookieForSession(s, p.CookieCipher)
if err != nil {
return err
}
p.SetSessionCookie(rw, req, value)
return nil
}
// RobotsTxt disallows scraping pages from the OAuthProxy
func (p *OAuthProxy) RobotsTxt(rw http.ResponseWriter) {
rw.WriteHeader(http.StatusOK)
fmt.Fprintf(rw, "User-agent: *\nDisallow: /")
}
// PingPage responds 200 OK to requests
func (p *OAuthProxy) PingPage(rw http.ResponseWriter) {
rw.WriteHeader(http.StatusOK)
fmt.Fprintf(rw, "OK")
}
// ErrorPage writes an error response
func (p *OAuthProxy) ErrorPage(rw http.ResponseWriter, code int, title string, message string) {
log.Printf("ErrorPage %d %s %s", code, title, message)
rw.WriteHeader(code)
t := struct {
Title string
Message string
ProxyPrefix string
}{
Title: fmt.Sprintf("%d %s", code, title),
Message: message,
ProxyPrefix: p.ProxyPrefix,
}
p.templates.ExecuteTemplate(rw, "error.html", t)
}
// SignInPage writes the sing in template to the response
func (p *OAuthProxy) SignInPage(rw http.ResponseWriter, req *http.Request, code int) {
p.ClearSessionCookie(rw, req)
rw.WriteHeader(code)
redirecURL := req.URL.RequestURI()
if req.Header.Get("X-Auth-Request-Redirect") != "" {
redirecURL = req.Header.Get("X-Auth-Request-Redirect")
}
if redirecURL == p.SignInPath {
redirecURL = "/"
}
t := struct {
ProviderName string
SignInMessage string
CustomLogin bool
Redirect string
Version string
ProxyPrefix string
Footer template.HTML
}{
ProviderName: p.provider.Data().ProviderName,
SignInMessage: p.SignInMessage,
CustomLogin: p.displayCustomLoginForm(),
Redirect: redirecURL,
Version: VERSION,
ProxyPrefix: p.ProxyPrefix,
Footer: template.HTML(p.Footer),
}
p.templates.ExecuteTemplate(rw, "sign_in.html", t)
}
// ManualSignIn handles basic auth logins to the proxy
func (p *OAuthProxy) ManualSignIn(rw http.ResponseWriter, req *http.Request) (string, bool) {
if req.Method != "POST" || p.HtpasswdFile == nil {
return "", false
}
user := req.FormValue("username")
passwd := req.FormValue("password")
if user == "" {
return "", false
}
// check auth
if p.HtpasswdFile.Validate(user, passwd) {
log.Printf("authenticated %q via HtpasswdFile", user)
return user, true
}
return "", false
}
// GetRedirect reads the query parameter to get the URL to redirect clients to
// once authenticated with the OAuthProxy
func (p *OAuthProxy) GetRedirect(req *http.Request) (redirect string, err error) {
err = req.ParseForm()
if err != nil {
return
}
redirect = req.Form.Get("rd")
if !p.IsValidRedirect(redirect) {
redirect = req.URL.Path
if strings.HasPrefix(redirect, p.ProxyPrefix) {
redirect = "/"
}
}
return
}
// IsValidRedirect checks whether the redirect URL is whitelisted
func (p *OAuthProxy) IsValidRedirect(redirect string) bool {
switch {
case strings.HasPrefix(redirect, "/") && !strings.HasPrefix(redirect, "//"):
return true
case strings.HasPrefix(redirect, "http://") || strings.HasPrefix(redirect, "https://"):
redirectURL, err := url.Parse(redirect)
if err != nil {
return false
}
for _, domain := range p.whitelistDomains {
if (redirectURL.Host == domain) || (strings.HasPrefix(domain, ".") && strings.HasSuffix(redirectURL.Host, domain)) {
return true
}
}
return false
default:
return false
}
}
// IsWhitelistedRequest is used to check if auth should be skipped for this request
func (p *OAuthProxy) IsWhitelistedRequest(req *http.Request) (ok bool) {
isPreflightRequestAllowed := p.skipAuthPreflight && req.Method == "OPTIONS"
return isPreflightRequestAllowed || p.IsWhitelistedPath(req.URL.Path)
}
// IsWhitelistedPath is used to check if the request path is allowed without auth
func (p *OAuthProxy) IsWhitelistedPath(path string) (ok bool) {
for _, u := range p.compiledRegex {
ok = u.MatchString(path)
if ok {
return
}
}
return
}
func getRemoteAddr(req *http.Request) (s string) {
s = req.RemoteAddr
if req.Header.Get("X-Real-IP") != "" {
s += fmt.Sprintf(" (%q)", req.Header.Get("X-Real-IP"))
}
return
}
func (p *OAuthProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
switch path := req.URL.Path; {
case path == p.RobotsPath:
p.RobotsTxt(rw)
case path == p.PingPath:
p.PingPage(rw)
case p.IsWhitelistedRequest(req):
p.serveMux.ServeHTTP(rw, req)
case path == p.SignInPath:
p.SignIn(rw, req)
case path == p.SignOutPath:
p.SignOut(rw, req)
case path == p.OAuthStartPath:
p.OAuthStart(rw, req)
case path == p.OAuthCallbackPath:
p.OAuthCallback(rw, req)
case path == p.AuthOnlyPath:
p.AuthenticateOnly(rw, req)
default:
p.Proxy(rw, req)
}
}
// SignIn serves a page prompting users to sign in
func (p *OAuthProxy) SignIn(rw http.ResponseWriter, req *http.Request) {
redirect, err := p.GetRedirect(req)
if err != nil {
p.ErrorPage(rw, 500, "Internal Error", err.Error())
return
}
user, ok := p.ManualSignIn(rw, req)
if ok {
session := &providers.SessionState{User: user}
p.SaveSession(rw, req, session)
http.Redirect(rw, req, redirect, 302)
} else {
if p.SkipProviderButton {
p.OAuthStart(rw, req)
} else {
p.SignInPage(rw, req, http.StatusOK)
}
}
}
// SignOut sends a response to clear the authentication cookie
func (p *OAuthProxy) SignOut(rw http.ResponseWriter, req *http.Request) {
p.ClearSessionCookie(rw, req)
http.Redirect(rw, req, "/", 302)
}
// OAuthStart starts the OAuth2 authentication flow
func (p *OAuthProxy) OAuthStart(rw http.ResponseWriter, req *http.Request) {
nonce, err := cookie.Nonce()
if err != nil {
p.ErrorPage(rw, 500, "Internal Error", err.Error())
return
}
p.SetCSRFCookie(rw, req, nonce)
redirect, err := p.GetRedirect(req)
if err != nil {
p.ErrorPage(rw, 500, "Internal Error", err.Error())
return
}
redirectURI := p.GetRedirectURI(req.Host)
http.Redirect(rw, req, p.provider.GetLoginURL(redirectURI, fmt.Sprintf("%v:%v", nonce, redirect)), 302)
}
// OAuthCallback is the OAuth2 authentication flow callback that finishes the
// OAuth2 authentication flow
func (p *OAuthProxy) OAuthCallback(rw http.ResponseWriter, req *http.Request) {
remoteAddr := getRemoteAddr(req)
// finish the oauth cycle
err := req.ParseForm()
if err != nil {
p.ErrorPage(rw, 500, "Internal Error", err.Error())
return
}
errorString := req.Form.Get("error")
if errorString != "" {
p.ErrorPage(rw, 403, "Permission Denied", errorString)
return
}
session, err := p.redeemCode(req.Host, req.Form.Get("code"))
if err != nil {
log.Printf("%s error redeeming code %s", remoteAddr, err)
p.ErrorPage(rw, 500, "Internal Error", "Internal Error")
return
}
s := strings.SplitN(req.Form.Get("state"), ":", 2)
if len(s) != 2 {
p.ErrorPage(rw, 500, "Internal Error", "Invalid State")
return
}
nonce := s[0]
redirect := s[1]
c, err := req.Cookie(p.CSRFCookieName)
if err != nil {
p.ErrorPage(rw, 403, "Permission Denied", err.Error())
return
}
p.ClearCSRFCookie(rw, req)
if c.Value != nonce {
log.Printf("%s csrf token mismatch, potential attack", remoteAddr)
p.ErrorPage(rw, 403, "Permission Denied", "csrf failed")
return
}
if !p.IsValidRedirect(redirect) {
redirect = "/"
}
// set cookie, or deny
if p.Validator(session.Email) && p.provider.ValidateGroup(session.Email) {
log.Printf("%s authentication complete %s", remoteAddr, session)
err := p.SaveSession(rw, req, session)
if err != nil {
log.Printf("%s %s", remoteAddr, err)
p.ErrorPage(rw, 500, "Internal Error", "Internal Error")
return
}
http.Redirect(rw, req, redirect, 302)
} else {
log.Printf("%s Permission Denied: %q is unauthorized", remoteAddr, session.Email)
p.ErrorPage(rw, 403, "Permission Denied", "Invalid Account")
}
}
// AuthenticateOnly checks whether the user is currently logged in
func (p *OAuthProxy) AuthenticateOnly(rw http.ResponseWriter, req *http.Request) {
status := p.Authenticate(rw, req)
if status == http.StatusAccepted {
rw.WriteHeader(http.StatusAccepted)
} else {
http.Error(rw, "unauthorized request", http.StatusUnauthorized)
}
}
// Proxy proxies the user request if the user is authenticated else it prompts
// them to authenticate
func (p *OAuthProxy) Proxy(rw http.ResponseWriter, req *http.Request) {
status := p.Authenticate(rw, req)
if status == http.StatusInternalServerError {
p.ErrorPage(rw, http.StatusInternalServerError,
"Internal Error", "Internal Error")
} else if status == http.StatusForbidden {
if p.SkipProviderButton {
p.OAuthStart(rw, req)
} else {
p.SignInPage(rw, req, http.StatusForbidden)
}
} else if status == http.StatusUnauthorized {
p.ErrorJSON(rw, status)
} else {
p.serveMux.ServeHTTP(rw, req)
}
}
// Authenticate checks whether a user is authenticated
func (p *OAuthProxy) Authenticate(rw http.ResponseWriter, req *http.Request) int {
var saveSession, clearSession, revalidated bool
remoteAddr := getRemoteAddr(req)
session, sessionAge, err := p.LoadCookiedSession(req)
if err != nil {
log.Printf("%s %s", remoteAddr, err)
}
if session != nil && sessionAge > p.CookieRefresh && p.CookieRefresh != time.Duration(0) {
log.Printf("%s refreshing %s old session cookie for %s (refresh after %s)", remoteAddr, sessionAge, session, p.CookieRefresh)
saveSession = true
}
var ok bool
if ok, err = p.provider.RefreshSessionIfNeeded(session); err != nil {
log.Printf("%s removing session. error refreshing access token %s %s", remoteAddr, err, session)
clearSession = true
session = nil
} else if ok {
saveSession = true
revalidated = true
}
if session != nil && session.IsExpired() {
log.Printf("%s removing session. token expired %s", remoteAddr, session)
session = nil
saveSession = false
clearSession = true
}
if saveSession && !revalidated && session != nil && session.AccessToken != "" {
if !p.provider.ValidateSessionState(session) {
log.Printf("%s removing session. error validating %s", remoteAddr, session)
saveSession = false
session = nil
clearSession = true
}
}
if session != nil && session.Email != "" && !p.Validator(session.Email) {
log.Printf("%s Permission Denied: removing session %s", remoteAddr, session)
session = nil
saveSession = false
clearSession = true
}
if saveSession && session != nil {
err = p.SaveSession(rw, req, session)
if err != nil {
log.Printf("%s %s", remoteAddr, err)
return http.StatusInternalServerError
}
}
if clearSession {
p.ClearSessionCookie(rw, req)
}
if session == nil {
session, err = p.CheckBasicAuth(req)
if err != nil {
log.Printf("%s %s", remoteAddr, err)
}
}
if session == nil {
// Check if is an ajax request and return unauthorized to avoid a redirect
// to the login page
if p.isAjax(req) {
return http.StatusUnauthorized
}
return http.StatusForbidden
}
// At this point, the user is authenticated. proxy normally
if p.PassBasicAuth {
req.SetBasicAuth(session.User, p.BasicAuthPassword)
req.Header["X-Forwarded-User"] = []string{session.User}
if session.Email != "" {
req.Header["X-Forwarded-Email"] = []string{session.Email}
}
}
if p.PassUserHeaders {
req.Header["X-Forwarded-User"] = []string{session.User}
if session.Email != "" {
req.Header["X-Forwarded-Email"] = []string{session.Email}
}
}
if p.SetXAuthRequest {
rw.Header().Set("X-Auth-Request-User", session.User)
if session.Email != "" {
rw.Header().Set("X-Auth-Request-Email", session.Email)
}
if p.PassAccessToken && session.AccessToken != "" {
rw.Header().Set("X-Auth-Request-Access-Token", session.AccessToken)
}
}
if p.PassAccessToken && session.AccessToken != "" {
req.Header["X-Forwarded-Access-Token"] = []string{session.AccessToken}
}
if p.PassAuthorization && session.IDToken != "" {
req.Header["Authorization"] = []string{fmt.Sprintf("Bearer %s", session.IDToken)}
}
if p.SetAuthorization && session.IDToken != "" {
rw.Header().Set("Authorization", fmt.Sprintf("Bearer %s", session.IDToken))
}
if session.Email == "" {
rw.Header().Set("GAP-Auth", session.User)
} else {
rw.Header().Set("GAP-Auth", session.Email)
}
return http.StatusAccepted
}
// CheckBasicAuth checks the requests Authorization header for basic auth
// credentials and authenticates these against the proxies HtpasswdFile
func (p *OAuthProxy) CheckBasicAuth(req *http.Request) (*providers.SessionState, error) {
if p.HtpasswdFile == nil {
return nil, nil
}
auth := req.Header.Get("Authorization")
if auth == "" {
return nil, nil
}
s := strings.SplitN(auth, " ", 2)
if len(s) != 2 || s[0] != "Basic" {
return nil, fmt.Errorf("invalid Authorization header %s", req.Header.Get("Authorization"))
}
b, err := b64.StdEncoding.DecodeString(s[1])
if err != nil {
return nil, err
}
pair := strings.SplitN(string(b), ":", 2)
if len(pair) != 2 {
return nil, fmt.Errorf("invalid format %s", b)
}
if p.HtpasswdFile.Validate(pair[0], pair[1]) {
log.Printf("authenticated %q via basic auth", pair[0])
return &providers.SessionState{User: pair[0]}, nil
}
return nil, fmt.Errorf("%s not in HtpasswdFile", pair[0])
}
// isAjax checks if a request is an ajax request
func (p *OAuthProxy) isAjax(req *http.Request) bool {
acceptValues, ok := req.Header["accept"]
if !ok {
acceptValues = req.Header["Accept"]
}
const ajaxReq = applicationJSON
for _, v := range acceptValues {
if v == ajaxReq {
return true
}
}
return false
}
// ErrorJSON returns the error code witht an application/json mime type
func (p *OAuthProxy) ErrorJSON(rw http.ResponseWriter, code int) {
rw.Header().Set("Content-Type", applicationJSON)
rw.WriteHeader(code)
}