pomerium/authenticate/handlers.go
Bobby DeSimone 426e003b03
proxy: add JWT request signing support (#19)
- Refactored middleware and request hander logging.
- Request refactored to use context.Context.
- Add helper (based on Alice) to allow middleware chaining.
- Add helper scripts to generate elliptic curve self-signed certificate that can be used to sign JWT.
- Changed LetsEncrypt scripts to use acme instead of certbot.
- Add script to have LetsEncrypt sign an RSA based certificate.
- Add documentation to explain how to verify headers.
- Refactored internal/cryptutil signer's code to expect a valid EC priv key.
- Changed JWT expiries to use default leeway period.
- Update docs and add screenshots.
- Replaced logging handler logic to use context.Context.
- Removed specific XML error handling.
- Refactored handler function signatures to prefer standard go idioms.
2019-01-22 21:44:22 -08:00

648 lines
22 KiB
Go

package authenticate // import "github.com/pomerium/pomerium/authenticate"
import (
"encoding/base64"
"encoding/json"
"fmt"
"net/http"
"net/url"
"strings"
"time"
"github.com/pomerium/pomerium/internal/cryptutil"
"github.com/pomerium/pomerium/internal/httputil"
"github.com/pomerium/pomerium/internal/log"
m "github.com/pomerium/pomerium/internal/middleware"
"github.com/pomerium/pomerium/internal/sessions"
"github.com/pomerium/pomerium/internal/version"
)
var securityHeaders = map[string]string{
"Strict-Transport-Security": "max-age=31536000",
"X-Frame-Options": "DENY",
"X-Content-Type-Options": "nosniff",
"X-XSS-Protection": "1; mode=block",
"Content-Security-Policy": "default-src 'none'; style-src 'self' 'sha256-pSTVzZsFAqd2U3QYu+BoBDtuJWaPM/+qMy/dBRrhb5Y='; img-src 'self';",
"Referrer-Policy": "Same-origin",
}
// Handler returns the Http.Handlers for authentication, callback, and refresh
func (p *Authenticate) Handler() http.Handler {
mux := http.NewServeMux()
// we setup global endpoints that should respond to any hostname
mux.HandleFunc("/ping", m.WithMethods(p.PingPage, "GET"))
serviceMux := http.NewServeMux()
// standard rest and healthcheck endpoints
serviceMux.HandleFunc("/ping", m.WithMethods(p.PingPage, "GET"))
serviceMux.HandleFunc("/robots.txt", m.WithMethods(p.RobotsTxt, "GET"))
// Identity Provider (IdP) endpoints and callbacks
serviceMux.HandleFunc("/start", m.WithMethods(p.OAuthStart, "GET"))
serviceMux.HandleFunc("/oauth2/callback", m.WithMethods(p.OAuthCallback, "GET"))
// authenticator-server endpoints, todo(bdd): make gRPC
serviceMux.HandleFunc("/sign_in", m.WithMethods(p.validateSignature(p.SignIn), "GET"))
serviceMux.HandleFunc("/sign_out", m.WithMethods(p.validateSignature(p.SignOut), "GET", "POST"))
serviceMux.HandleFunc("/profile", m.WithMethods(p.validateExisting(p.GetProfile), "GET"))
serviceMux.HandleFunc("/validate", m.WithMethods(p.validateExisting(p.ValidateToken), "GET"))
serviceMux.HandleFunc("/redeem", m.WithMethods(p.validateExisting(p.Redeem), "POST"))
serviceMux.HandleFunc("/refresh", m.WithMethods(p.validateExisting(p.Refresh), "POST"))
// NOTE: we have to include trailing slash for the router to match the host header
host := p.RedirectURL.Host
if !strings.HasSuffix(host, "/") {
host = fmt.Sprintf("%s/", host)
}
mux.Handle(host, serviceMux) // setup our service mux to only handle our required host header
return m.SetHeadersOld(mux, securityHeaders)
}
// validateSignature wraps a common collection of middlewares to validate signatures
func (p *Authenticate) validateSignature(f http.HandlerFunc) http.HandlerFunc {
return validateRedirectURI(validateSignature(f, p.SharedKey), p.ProxyRootDomains)
}
// validateSignature wraps a common collection of middlewares to validate
// a (presumably) existing user session
func (p *Authenticate) validateExisting(f http.HandlerFunc) http.HandlerFunc {
return m.ValidateClientSecret(f, p.SharedKey)
}
// RobotsTxt handles the /robots.txt route.
func (p *Authenticate) RobotsTxt(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
fmt.Fprintf(w, "User-agent: *\nDisallow: /")
}
// PingPage handles the /ping route
func (p *Authenticate) PingPage(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
fmt.Fprintf(w, "OK")
}
// SignInPage directs the user to the sign in page. Takes a `redirect_uri` param.
func (p *Authenticate) SignInPage(w http.ResponseWriter, r *http.Request) {
// requestLog := log.WithRequest(req, "authenticate.SignInPage")
redirectURL := p.RedirectURL.ResolveReference(r.URL)
// validateRedirectURI middleware already ensures that this is a valid URL
destinationURL, _ := url.Parse(redirectURL.Query().Get("redirect_uri"))
t := struct {
ProviderName string
AllowedDomains []string
Redirect string
Destination string
Version string
}{
ProviderName: p.provider.Data().ProviderName,
AllowedDomains: p.AllowedDomains,
Redirect: redirectURL.String(),
Destination: destinationURL.Host,
Version: version.FullVersion(),
}
log.Ctx(r.Context()).Info().
Str("ProviderName", p.provider.Data().ProviderName).
Str("Redirect", redirectURL.String()).
Str("Destination", destinationURL.Host).
Str("AllowedDomains", strings.Join(p.AllowedDomains, ", ")).
Msg("authenticate.SignInPage")
w.WriteHeader(http.StatusOK)
p.templates.ExecuteTemplate(w, "sign_in.html", t)
}
func (p *Authenticate) authenticate(w http.ResponseWriter, r *http.Request) (*sessions.SessionState, error) {
// requestLog := log.WithRequest(req, "authenticate.authenticate")
session, err := p.sessionStore.LoadSession(r)
if err != nil {
log.Error().Err(err).Msg("authenticate.authenticate")
p.sessionStore.ClearSession(w, r)
return nil, err
}
// ensure sessions lifetime has not expired
if session.LifetimePeriodExpired() {
log.Ctx(r.Context()).Warn().Msg("lifetime expired")
p.sessionStore.ClearSession(w, r)
return nil, sessions.ErrLifetimeExpired
}
// check if session refresh period is up
if session.RefreshPeriodExpired() {
ok, err := p.provider.RefreshSessionIfNeeded(session)
if err != nil {
log.Ctx(r.Context()).Error().Err(err).Msg("failed to refresh session")
p.sessionStore.ClearSession(w, r)
return nil, err
}
if !ok {
log.Ctx(r.Context()).Error().Msg("user unauthorized after refresh")
p.sessionStore.ClearSession(w, r)
return nil, httputil.ErrUserNotAuthorized
}
// update refresh'd session in cookie
err = p.sessionStore.SaveSession(w, r, session)
if err != nil {
// We refreshed the session successfully, but failed to save it.
// This could be from failing to encode the session properly.
// But, we clear the session cookie and reject the request
log.Ctx(r.Context()).Error().Err(err).Msg("could not save refreshed session")
p.sessionStore.ClearSession(w, r)
return nil, err
}
} else {
// The session has not exceeded it's lifetime or requires refresh
ok := p.provider.ValidateSessionState(session)
if !ok {
log.Ctx(r.Context()).Error().Msg("invalid session state")
p.sessionStore.ClearSession(w, r)
return nil, httputil.ErrUserNotAuthorized
}
err = p.sessionStore.SaveSession(w, r, session)
if err != nil {
log.Ctx(r.Context()).Error().Err(err).Msg("failed to save valid session")
p.sessionStore.ClearSession(w, r)
return nil, err
}
}
if !p.Validator(session.Email) {
log.Ctx(r.Context()).Error().Msg("invalid email user")
return nil, httputil.ErrUserNotAuthorized
}
return session, nil
}
// SignIn handles the /sign_in endpoint. It attempts to authenticate the user,
// and if the user is not authenticated, it renders a sign in page.
func (p *Authenticate) SignIn(w http.ResponseWriter, r *http.Request) {
// We attempt to authenticate the user. If they cannot be authenticated, we render a sign-in
// page.
//
// If the user is authenticated, we redirect back to the proxy application
// at the `redirect_uri`, with a temporary token.
//
// TODO: It is possible for a user to visit this page without a redirect destination.
// Should we allow the user to authenticate? If not, what should be the proposed workflow?
session, err := p.authenticate(w, r)
switch err {
case nil:
// User is authenticated, redirect back to the proxy application
// with the necessary state
p.ProxyOAuthRedirect(w, r, session)
case http.ErrNoCookie:
log.Error().Err(err).Msg("authenticate.SignIn : err no cookie")
if p.skipProviderButton {
p.skipButtonOAuthStart(w, r)
} else {
p.SignInPage(w, r)
}
case sessions.ErrLifetimeExpired, sessions.ErrInvalidSession:
log.Error().Err(err).Msg("authenticate.SignIn : invalid cookie cookie")
p.sessionStore.ClearSession(w, r)
if p.skipProviderButton {
p.skipButtonOAuthStart(w, r)
} else {
p.SignInPage(w, r)
}
default:
log.Error().Err(err).Msg("authenticate.SignIn : unknown error cookie")
httputil.ErrorResponse(w, r, err.Error(), httputil.CodeForError(err))
}
}
// ProxyOAuthRedirect redirects the user back to sso proxy's redirection endpoint.
func (p *Authenticate) ProxyOAuthRedirect(w http.ResponseWriter, r *http.Request, session *sessions.SessionState) {
// This workflow corresponds to Section 3.1.2 of the OAuth2 RFC.
// See https://tools.ietf.org/html/rfc6749#section-3.1.2 for more specific information.
//
// We redirect the user back to the proxy application's redirection endpoint; in the
// sso proxy, this is the `/oauth/callback` endpoint.
//
// We must provide the proxy with a temporary authorization code via the `code` parameter,
// which they can use to redeem an access token for subsequent API calls.
//
// We must also include the original `state` parameter received from the proxy application.
err := r.ParseForm()
if err != nil {
httputil.ErrorResponse(w, r, err.Error(), http.StatusInternalServerError)
return
}
state := r.Form.Get("state")
if state == "" {
httputil.ErrorResponse(w, r, "no state parameter supplied", http.StatusForbidden)
return
}
redirectURI := r.Form.Get("redirect_uri")
if redirectURI == "" {
httputil.ErrorResponse(w, r, "no redirect_uri parameter supplied", http.StatusForbidden)
return
}
redirectURL, err := url.Parse(redirectURI)
if err != nil {
httputil.ErrorResponse(w, r, "malformed redirect_uri parameter passed", http.StatusBadRequest)
return
}
encrypted, err := sessions.MarshalSession(session, p.cipher)
if err != nil {
httputil.ErrorResponse(w, r, err.Error(), http.StatusInternalServerError)
return
}
http.Redirect(w, r, getAuthCodeRedirectURL(redirectURL, state, string(encrypted)), http.StatusFound)
}
func getAuthCodeRedirectURL(redirectURL *url.URL, state, authCode string) string {
u, _ := url.Parse(redirectURL.String())
params, _ := url.ParseQuery(u.RawQuery)
params.Set("code", authCode)
params.Set("state", state)
u.RawQuery = params.Encode()
if u.Scheme == "" {
u.Scheme = "https"
}
return u.String()
}
// SignOut signs the user out.
func (p *Authenticate) SignOut(w http.ResponseWriter, r *http.Request) {
redirectURI := r.Form.Get("redirect_uri")
if r.Method == "GET" {
p.SignOutPage(w, r, "")
return
}
session, err := p.sessionStore.LoadSession(r)
switch err {
case nil:
break
case http.ErrNoCookie: // if there's no cookie in the session we can just redirect
http.Redirect(w, r, redirectURI, http.StatusFound)
return
default:
// a different error, clear the session cookie and redirect
log.Error().Err(err).Msg("authenticate.SignOut : error loading cookie session")
p.sessionStore.ClearSession(w, r)
http.Redirect(w, r, redirectURI, http.StatusFound)
return
}
err = p.provider.Revoke(session)
if err != nil {
log.Error().Err(err).Msg("authenticate.SignOut : error revoking session")
p.SignOutPage(w, r, "An error occurred during sign out. Please try again.")
return
}
p.sessionStore.ClearSession(w, r)
http.Redirect(w, r, redirectURI, http.StatusFound)
}
// SignOutPage renders a sign out page with a message
func (p *Authenticate) SignOutPage(w http.ResponseWriter, r *http.Request, message string) {
log.FromRequest(r).Debug().Msg("This is just a test to make sure signout works")
// validateRedirectURI middleware already ensures that this is a valid URL
redirectURI := r.Form.Get("redirect_uri")
session, err := p.sessionStore.LoadSession(r)
if err != nil {
http.Redirect(w, r, redirectURI, http.StatusFound)
return
}
signature := r.Form.Get("sig")
timestamp := r.Form.Get("ts")
destinationURL, _ := url.Parse(redirectURI)
// An error message indicates that an internal server error occurred
if message != "" {
w.WriteHeader(http.StatusInternalServerError)
}
t := struct {
Redirect string
Signature string
Timestamp string
Message string
Destination string
Email string
Version string
}{
Redirect: redirectURI,
Signature: signature,
Timestamp: timestamp,
Message: message,
Destination: destinationURL.Host,
Email: session.Email,
Version: version.FullVersion(),
}
p.templates.ExecuteTemplate(w, "sign_out.html", t)
return
}
// OAuthStart starts the authentication process by redirecting to the provider. It provides a
// `redirectURI`, allowing the provider to redirect back to the sso proxy after authentication.
func (p *Authenticate) OAuthStart(w http.ResponseWriter, r *http.Request) {
authRedirectURL, err := url.Parse(r.URL.Query().Get("redirect_uri"))
if err != nil {
httputil.ErrorResponse(w, r, "Invalid redirect parameter", http.StatusBadRequest)
return
}
p.helperOAuthStart(w, r, authRedirectURL)
}
func (p *Authenticate) skipButtonOAuthStart(w http.ResponseWriter, r *http.Request) {
p.helperOAuthStart(w, r, p.RedirectURL.ResolveReference(r.URL))
}
func (p *Authenticate) helperOAuthStart(w http.ResponseWriter, r *http.Request, authRedirectURL *url.URL) {
nonce := fmt.Sprintf("%x", cryptutil.GenerateKey())
p.csrfStore.SetCSRF(w, r, nonce)
if !validRedirectURI(authRedirectURL.String(), p.ProxyRootDomains) {
httputil.ErrorResponse(w, r, "Invalid redirect parameter", http.StatusBadRequest)
return
}
proxyRedirectURL, err := url.Parse(authRedirectURL.Query().Get("redirect_uri"))
if err != nil || !validRedirectURI(proxyRedirectURL.String(), p.ProxyRootDomains) {
httputil.ErrorResponse(w, r, "Invalid redirect parameter", http.StatusBadRequest)
return
}
proxyRedirectSig := authRedirectURL.Query().Get("sig")
ts := authRedirectURL.Query().Get("ts")
if !validSignature(proxyRedirectURL.String(), proxyRedirectSig, ts, p.SharedKey) {
httputil.ErrorResponse(w, r, "Invalid redirect parameter", http.StatusBadRequest)
return
}
state := base64.URLEncoding.EncodeToString([]byte(fmt.Sprintf("%v:%v", nonce, authRedirectURL.String())))
signInURL := p.provider.GetSignInURL(state)
http.Redirect(w, r, signInURL, http.StatusFound)
}
func (p *Authenticate) redeemCode(host, code string) (*sessions.SessionState, error) {
session, err := p.provider.Redeem(code)
if err != nil {
return nil, err
}
if session.Email == "" {
return nil, fmt.Errorf("no email included in session")
}
return session, nil
}
// getOAuthCallback completes the oauth cycle from an identity provider's callback
func (p *Authenticate) getOAuthCallback(w http.ResponseWriter, r *http.Request) (string, error) {
// requestLog := log.WithRequest(req, "authenticate.getOAuthCallback")
// finish the oauth cycle
err := r.ParseForm()
if err != nil {
return "", httputil.HTTPError{Code: http.StatusInternalServerError, Message: err.Error()}
}
errorString := r.Form.Get("error")
if errorString != "" {
return "", httputil.HTTPError{Code: http.StatusForbidden, Message: errorString}
}
code := r.Form.Get("code")
if code == "" {
return "", httputil.HTTPError{Code: http.StatusBadRequest, Message: "Missing Code"}
}
session, err := p.redeemCode(r.Host, code)
if err != nil {
log.Ctx(r.Context()).Error().Err(err).Msg("error redeeming authentication code")
return "", err
}
bytes, err := base64.URLEncoding.DecodeString(r.Form.Get("state"))
if err != nil {
return "", httputil.HTTPError{Code: http.StatusInternalServerError, Message: "Invalid State"}
}
s := strings.SplitN(string(bytes), ":", 2)
if len(s) != 2 {
return "", httputil.HTTPError{Code: http.StatusInternalServerError, Message: "Invalid State"}
}
nonce := s[0]
redirect := s[1]
c, err := p.csrfStore.GetCSRF(r)
if err != nil {
return "", httputil.HTTPError{Code: http.StatusForbidden, Message: "Missing CSRF token"}
}
p.csrfStore.ClearCSRF(w, r)
if c.Value != nonce {
log.Ctx(r.Context()).Error().Err(err).Msg("csrf token mismatch")
return "", httputil.HTTPError{Code: http.StatusForbidden, Message: "csrf failed"}
}
if !validRedirectURI(redirect, p.ProxyRootDomains) {
return "", httputil.HTTPError{Code: http.StatusForbidden, Message: "Invalid Redirect URI"}
}
// Set cookie, or deny: validates the session email and group
// - for p.Validator see validator.go#newValidatorImpl for more info
// - for p.provider.ValidateGroup see providers/google.go#ValidateGroup for more info
if !p.Validator(session.Email) {
log.Ctx(r.Context()).Error().Err(err).Str("email", session.Email).Msg("invalid email permissions denied")
return "", httputil.HTTPError{Code: http.StatusForbidden, Message: "Invalid Account"}
}
log.Ctx(r.Context()).Info().Str("email", session.Email).Msg("authentication complete")
err = p.sessionStore.SaveSession(w, r, session)
if err != nil {
log.Ctx(r.Context()).Error().Err(err).Msg("internal error")
return "", httputil.HTTPError{Code: http.StatusInternalServerError, Message: "Internal Error"}
}
return redirect, nil
}
// OAuthCallback handles the callback from the provider, and returns an error response if there is an error.
// If there is no error it will redirect to the redirect url.
func (p *Authenticate) OAuthCallback(w http.ResponseWriter, r *http.Request) {
redirect, err := p.getOAuthCallback(w, r)
switch h := err.(type) {
case nil:
break
case httputil.HTTPError:
httputil.ErrorResponse(w, r, h.Message, h.Code)
return
default:
httputil.ErrorResponse(w, r, "Internal Error", http.StatusInternalServerError)
return
}
http.Redirect(w, r, redirect, http.StatusFound)
}
// Redeem has a signed access token, and provides the user information associated with the access token.
func (p *Authenticate) Redeem(w http.ResponseWriter, r *http.Request) {
// The auth code is redeemed by the sso proxy for an access token, refresh token,
// expiration, and email.
// requestLog := log.WithRequest(req, "authenticate.Redeem")
err := r.ParseForm()
if err != nil {
http.Error(w, fmt.Sprintf("Bad Request: %s", err.Error()), http.StatusBadRequest)
return
}
session, err := sessions.UnmarshalSession(r.Form.Get("code"), p.cipher)
if err != nil {
log.Ctx(r.Context()).Error().Err(err).Int("http-status", http.StatusUnauthorized).Msg("invalid auth code")
http.Error(w, fmt.Sprintf("invalid auth code: %s", err.Error()), http.StatusUnauthorized)
return
}
if session == nil {
log.Ctx(r.Context()).Error().Err(err).Int("http-status", http.StatusUnauthorized).Msg("invalid session")
http.Error(w, fmt.Sprintf("invalid session: %s", err.Error()), http.StatusUnauthorized)
return
}
if session != nil && (session.RefreshPeriodExpired() || session.LifetimePeriodExpired()) {
log.Ctx(r.Context()).Error().Msg("expired session")
p.sessionStore.ClearSession(w, r)
http.Error(w, fmt.Sprintf("expired session"), http.StatusUnauthorized)
return
}
response := struct {
AccessToken string `json:"access_token"`
RefreshToken string `json:"refresh_token"`
IDToken string `json:"id_token"`
ExpiresIn int64 `json:"expires_in"`
Email string `json:"email"`
}{
AccessToken: session.AccessToken,
RefreshToken: session.RefreshToken,
IDToken: session.IDToken,
ExpiresIn: int64(session.RefreshDeadline.Sub(time.Now()).Seconds()),
Email: session.Email,
}
jsonBytes, err := json.Marshal(response)
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
return
}
w.Header().Set("GAP-Auth", session.Email)
w.Header().Set("Content-Type", "application/json")
w.Write(jsonBytes)
}
// Refresh takes a refresh token and returns a new access token
func (p *Authenticate) Refresh(w http.ResponseWriter, r *http.Request) {
err := r.ParseForm()
if err != nil {
http.Error(w, fmt.Sprintf("Bad Request: %s", err.Error()), http.StatusBadRequest)
return
}
refreshToken := r.Form.Get("refresh_token")
if refreshToken == "" {
http.Error(w, "Bad Request: No Refresh Token", http.StatusBadRequest)
return
}
accessToken, expiresIn, err := p.provider.RefreshAccessToken(refreshToken)
if err != nil {
httputil.ErrorResponse(w, r, err.Error(), httputil.CodeForError(err))
return
}
response := struct {
AccessToken string `json:"access_token"`
ExpiresIn int64 `json:"expires_in"`
}{
AccessToken: accessToken,
ExpiresIn: int64(expiresIn.Seconds()),
}
bytes, err := json.Marshal(response)
if err != nil {
w.WriteHeader(http.StatusInternalServerError)
return
}
w.WriteHeader(http.StatusCreated)
w.Header().Set("Content-Type", "application/json")
w.Write(bytes)
}
// GetProfile gets a list of groups of which a user is a member.
func (p *Authenticate) GetProfile(w http.ResponseWriter, r *http.Request) {
// The sso proxy sends the user's email to this endpoint to get a list of Google groups that
// the email is a member of. The proxy will compare these groups to the list of allowed
// groups for the upstream service the user is trying to access.
email := r.FormValue("email")
if email == "" {
http.Error(w, "no email address included", http.StatusBadRequest)
return
}
// groupsFormValue := r.FormValue("groups")
// allowedGroups := []string{}
// if groupsFormValue != "" {
// allowedGroups = strings.Split(groupsFormValue, ",")
// }
// groups, err := p.provider.ValidateGroupMembership(email, allowedGroups)
// if err != nil {
// log.Error().Err(err).Msg("authenticate.GetProfile : error retrieving groups")
// httputil.ErrorResponse(w, r, err.Error(), httputil.CodeForError(err))
// return
// }
response := struct {
Email string `json:"email"`
}{
Email: email,
}
jsonBytes, err := json.Marshal(response)
if err != nil {
http.Error(w, fmt.Sprintf("error marshaling response: %s", err.Error()), http.StatusInternalServerError)
return
}
w.Header().Set("GAP-Auth", email)
w.Header().Set("Content-Type", "application/json")
w.Write(jsonBytes)
}
// ValidateToken validates the X-Access-Token from the header and returns an error response
// if it's invalid
func (p *Authenticate) ValidateToken(w http.ResponseWriter, r *http.Request) {
accessToken := r.Header.Get("X-Access-Token")
idToken := r.Header.Get("X-Id-Token")
if accessToken == "" {
w.WriteHeader(http.StatusBadRequest)
return
}
if idToken == "" {
w.WriteHeader(http.StatusBadRequest)
return
}
ok := p.provider.ValidateSessionState(&sessions.SessionState{
AccessToken: accessToken,
IDToken: idToken,
})
if !ok {
w.WriteHeader(http.StatusUnauthorized)
return
}
w.WriteHeader(http.StatusOK)
return
}