package proxy import ( "context" "errors" "fmt" "net/http" "net/url" "strings" sessionsapi "github.com/oauth2-proxy/oauth2-proxy/pkg/apis/sessions" "github.com/oauth2-proxy/oauth2-proxy/pkg/encryption" "github.com/oauth2-proxy/oauth2-proxy/pkg/ip" ) // 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() } 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) redeemCode(ctx context.Context, host, code string) (s *sessionsapi.SessionState, err error) { if code == "" { return nil, errors.New("missing code") } redirectURI := p.GetRedirectURI(host) s, err = p.provider.Redeem(ctx, redirectURI, code) if err != nil { return } if s.Email == "" { s.Email, err = p.provider.GetEmailAddress(ctx, s) } if s.PreferredUsername == "" { s.PreferredUsername, err = p.provider.GetPreferredUsername(ctx, s) if err != nil && err.Error() == "not implemented" { err = nil } } if s.User == "" { s.User, err = p.provider.GetUserName(ctx, s) if err != nil && err.Error() == "not implemented" { err = nil } } return } // 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.Header.Get("X-Auth-Request-Redirect") if req.Form.Get("rd") != "" { redirect = req.Form.Get("rd") } if !p.IsValidRedirect(redirect) { // Use RequestURI to preserve ?query redirect = req.URL.RequestURI() 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 redirect == "": // The user didn't specify a redirect, should fallback to `/` return false case strings.HasPrefix(redirect, "/") && !strings.HasPrefix(redirect, "//") && !invalidRedirectRegex.MatchString(redirect): return true case strings.HasPrefix(redirect, "http://") || strings.HasPrefix(redirect, "https://"): redirectURL, err := url.Parse(redirect) if err != nil { p.logger.Printf("Rejecting invalid redirect %q: scheme unsupported or missing", redirect) return false } redirectHostname := redirectURL.Hostname() for _, domain := range p.whitelistDomains { domainHostname, domainPort := splitHostPort(strings.TrimLeft(domain, ".")) if domainHostname == "" { continue } if (redirectHostname == domainHostname) || (strings.HasPrefix(domain, ".") && strings.HasSuffix(redirectHostname, domainHostname)) { // the domain names match, now validate the ports // if the whitelisted domain's port is '*', allow all ports // if the whitelisted domain contains a specific port, only allow that port // if the whitelisted domain doesn't contain a port at all, only allow empty redirect ports ie http and https redirectPort := redirectURL.Port() if (domainPort == "*") || (domainPort == redirectPort) || (domainPort == "" && redirectPort == "") { return true } } } p.logger.Printf("Rejecting invalid redirect %q: domain / port not in whitelist", redirect) return false default: p.logger.Printf("Rejecting invalid redirect %q: not an absolute or relative URL", redirect) return false } } // IsWhitelistedRequest is used to check if auth should be skipped for this request func (p *OAuthProxy) IsWhitelistedRequest(req *http.Request) 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) bool { for _, u := range p.compiledRegex { if u.MatchString(path) { return true } } return false } // OAuthStart starts the OAuth2 authentication flow func (p *OAuthProxy) OAuthStart(rw http.ResponseWriter, req *http.Request) { prepareNoCache(rw) nonce, err := encryption.Nonce() if err != nil { p.logger.Errorf("Error obtaining nonce: %v", err) p.ErrorPage(rw, http.StatusInternalServerError, "Internal Server Error", err.Error()) return } p.SetCSRFCookie(rw, req, nonce) redirect, err := p.GetRedirect(req) if err != nil { p.logger.Errorf("Error obtaining redirect: %v", err) p.ErrorPage(rw, http.StatusInternalServerError, "Internal Server Error", err.Error()) return } redirectURI := p.GetRedirectURI(req.Host) http.Redirect(rw, req, p.provider.GetLoginURL(redirectURI, fmt.Sprintf("%v:%v", nonce, redirect)), http.StatusFound) } // OAuthCallback is the OAuth2 authentication flow callback that finishes the // OAuth2 authentication flow func (p *OAuthProxy) OAuthCallback(rw http.ResponseWriter, req *http.Request) { remoteAddr := ip.GetClientString(p.realClientIPParser, req, true) // finish the oauth cycle err := req.ParseForm() if err != nil { p.logger.Errorf("Error while parsing OAuth2 callback: %v", err) p.ErrorPage(rw, http.StatusInternalServerError, "Internal Server Error", err.Error()) return } errorString := req.Form.Get("error") if errorString != "" { p.logger.Errorf("Error while parsing OAuth2 callback: %s", errorString) p.ErrorPage(rw, http.StatusForbidden, "Permission Denied", errorString) return } session, err := p.redeemCode(req.Context(), req.Host, req.Form.Get("code")) if err != nil { p.logger.Errorf("Error redeeming code during OAuth2 callback: %v", err) p.ErrorPage(rw, http.StatusInternalServerError, "Internal Server Error", "Internal Error") return } s := strings.SplitN(req.Form.Get("state"), ":", 2) if len(s) != 2 { p.logger.Error("Error while parsing OAuth2 state: invalid length") p.ErrorPage(rw, http.StatusInternalServerError, "Internal Server Error", "Invalid State") return } nonce := s[0] redirect := s[1] c, err := req.Cookie(p.CSRFCookieName) if err != nil { p.logger.WithField("user", session.Email).WithField("status", "AuthFailure").Info("Invalid authentication via OAuth2: unable to obtain CSRF cookie") p.ErrorPage(rw, http.StatusForbidden, "Permission Denied", err.Error()) return } p.ClearCSRFCookie(rw, req) if c.Value != nonce { p.logger.WithField("is", c.Value).WithField("should", nonce).WithField("user", session.Email).WithField("status", "AuthFailure").Info("Invalid authentication via OAuth2: CSRF token mismatch, potential attack") p.ErrorPage(rw, http.StatusForbidden, "Permission Denied", "CSRF Failed") return } if !p.IsValidRedirect(redirect) { redirect = "/" } // set cookie, or deny if p.provider.ValidateGroup(session.Email) { p.logger.WithField("user", session.Email).WithField("status", "AuthFailure").Infof("Authenticated via OAuth2: %s", session) err := p.SaveSession(rw, req, session) if err != nil { p.logger.Printf("Error saving session state for %s: %v", remoteAddr, err) p.ErrorPage(rw, http.StatusInternalServerError, "Internal Server Error", err.Error()) return } http.Redirect(rw, req, redirect, http.StatusFound) } else { p.logger.WithField("user", session.Email).WithField("status", "AuthFailure").Info("Invalid authentication via OAuth2: unauthorized") p.ErrorPage(rw, http.StatusForbidden, "Permission Denied", "Invalid Account") } }