ContainerImage.Pinniped/internal/oidc/callback/callback_handler.go
Monis Khan 3c3da9e75d
Wire in new env vars for user info testing
Signed-off-by: Monis Khan <mok@vmware.com>
2021-01-12 11:23:25 -05:00

310 lines
10 KiB
Go

// Copyright 2020 the Pinniped contributors. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
// Package callback provides a handler for the OIDC callback endpoint.
package callback
import (
"crypto/subtle"
"fmt"
"net/http"
"net/url"
"time"
coreosoidc "github.com/coreos/go-oidc"
"github.com/ory/fosite"
"github.com/ory/fosite/handler/openid"
"github.com/ory/fosite/token/jwt"
"go.pinniped.dev/internal/httputil/httperr"
"go.pinniped.dev/internal/httputil/securityheader"
"go.pinniped.dev/internal/oidc"
"go.pinniped.dev/internal/oidc/csrftoken"
"go.pinniped.dev/internal/oidc/provider"
"go.pinniped.dev/internal/plog"
)
func NewHandler(
idpListGetter oidc.IDPListGetter,
oauthHelper fosite.OAuth2Provider,
stateDecoder, cookieDecoder oidc.Decoder,
redirectURI string,
) http.Handler {
return securityheader.Wrap(httperr.HandlerFunc(func(w http.ResponseWriter, r *http.Request) error {
state, err := validateRequest(r, stateDecoder, cookieDecoder)
if err != nil {
return err
}
upstreamIDPConfig := findUpstreamIDPConfig(state.UpstreamName, idpListGetter)
if upstreamIDPConfig == nil {
plog.Warning("upstream provider not found")
return httperr.New(http.StatusUnprocessableEntity, "upstream provider not found")
}
downstreamAuthParams, err := url.ParseQuery(state.AuthParams)
if err != nil {
plog.Error("error reading state downstream auth params", err)
return httperr.New(http.StatusBadRequest, "error reading state downstream auth params")
}
// Recreate enough of the original authorize request so we can pass it to NewAuthorizeRequest().
reconstitutedAuthRequest := &http.Request{Form: downstreamAuthParams}
authorizeRequester, err := oauthHelper.NewAuthorizeRequest(r.Context(), reconstitutedAuthRequest)
if err != nil {
plog.Error("error using state downstream auth params", err)
return httperr.New(http.StatusBadRequest, "error using state downstream auth params")
}
// Automatically grant the openid, offline_access, and pinniped:request-audience scopes, but only if they were requested.
oidc.GrantScopeIfRequested(authorizeRequester, coreosoidc.ScopeOpenID)
oidc.GrantScopeIfRequested(authorizeRequester, coreosoidc.ScopeOfflineAccess)
oidc.GrantScopeIfRequested(authorizeRequester, "pinniped:request-audience")
token, err := upstreamIDPConfig.ExchangeAuthcodeAndValidateTokens(
r.Context(),
authcode(r),
state.PKCECode,
state.Nonce,
redirectURI,
)
if err != nil {
plog.WarningErr("error exchanging and validating upstream tokens", err, "upstreamName", upstreamIDPConfig.GetName())
return httperr.New(http.StatusBadGateway, "error exchanging and validating upstream tokens")
}
subject, username, err := getSubjectAndUsernameFromUpstreamIDToken(upstreamIDPConfig, token.IDToken.Claims)
if err != nil {
return err
}
groups, err := getGroupsFromUpstreamIDToken(upstreamIDPConfig, token.IDToken.Claims)
if err != nil {
return err
}
openIDSession := makeDownstreamSession(subject, username, groups)
authorizeResponder, err := oauthHelper.NewAuthorizeResponse(r.Context(), authorizeRequester, openIDSession)
if err != nil {
plog.WarningErr("error while generating and saving authcode", err, "upstreamName", upstreamIDPConfig.GetName())
return httperr.Wrap(http.StatusInternalServerError, "error while generating and saving authcode", err)
}
oauthHelper.WriteAuthorizeResponse(w, authorizeRequester, authorizeResponder)
return nil
}))
}
func authcode(r *http.Request) string {
return r.FormValue("code")
}
func validateRequest(r *http.Request, stateDecoder, cookieDecoder oidc.Decoder) (*oidc.UpstreamStateParamData, error) {
if r.Method != http.MethodGet {
return nil, httperr.Newf(http.StatusMethodNotAllowed, "%s (try GET)", r.Method)
}
csrfValue, err := readCSRFCookie(r, cookieDecoder)
if err != nil {
plog.InfoErr("error reading CSRF cookie", err)
return nil, err
}
if authcode(r) == "" {
plog.Info("code param not found")
return nil, httperr.New(http.StatusBadRequest, "code param not found")
}
if r.FormValue("state") == "" {
plog.Info("state param not found")
return nil, httperr.New(http.StatusBadRequest, "state param not found")
}
state, err := readState(r, stateDecoder)
if err != nil {
plog.InfoErr("error reading state", err)
return nil, err
}
if subtle.ConstantTimeCompare([]byte(state.CSRFToken), []byte(csrfValue)) != 1 {
plog.InfoErr("CSRF value does not match", err)
return nil, httperr.Wrap(http.StatusForbidden, "CSRF value does not match", err)
}
return state, nil
}
func findUpstreamIDPConfig(upstreamName string, idpListGetter oidc.IDPListGetter) provider.UpstreamOIDCIdentityProviderI {
for _, p := range idpListGetter.GetIDPList() {
if p.GetName() == upstreamName {
return p
}
}
return nil
}
func readCSRFCookie(r *http.Request, cookieDecoder oidc.Decoder) (csrftoken.CSRFToken, error) {
receivedCSRFCookie, err := r.Cookie(oidc.CSRFCookieName)
if err != nil {
// Error means that the cookie was not found
return "", httperr.Wrap(http.StatusForbidden, "CSRF cookie is missing", err)
}
var csrfFromCookie csrftoken.CSRFToken
err = cookieDecoder.Decode(oidc.CSRFCookieEncodingName, receivedCSRFCookie.Value, &csrfFromCookie)
if err != nil {
return "", httperr.Wrap(http.StatusForbidden, "error reading CSRF cookie", err)
}
return csrfFromCookie, nil
}
func readState(r *http.Request, stateDecoder oidc.Decoder) (*oidc.UpstreamStateParamData, error) {
var state oidc.UpstreamStateParamData
if err := stateDecoder.Decode(
oidc.UpstreamStateParamEncodingName,
r.FormValue("state"),
&state,
); err != nil {
return nil, httperr.New(http.StatusBadRequest, "error reading state")
}
if state.FormatVersion != oidc.UpstreamStateParamFormatVersion {
return nil, httperr.New(http.StatusUnprocessableEntity, "state format version is invalid")
}
return &state, nil
}
func getSubjectAndUsernameFromUpstreamIDToken(
upstreamIDPConfig provider.UpstreamOIDCIdentityProviderI,
idTokenClaims map[string]interface{},
) (string, string, error) {
// The spec says the "sub" claim is only unique per issuer,
// so we will prepend the issuer string to make it globally unique.
upstreamIssuer := idTokenClaims[oidc.IDTokenIssuerClaim]
if upstreamIssuer == "" {
plog.Warning(
"issuer claim in upstream ID token missing",
"upstreamName", upstreamIDPConfig.GetName(),
"issClaim", upstreamIssuer,
)
return "", "", httperr.New(http.StatusUnprocessableEntity, "issuer claim in upstream ID token missing")
}
upstreamIssuerAsString, ok := upstreamIssuer.(string)
if !ok {
plog.Warning(
"issuer claim in upstream ID token has invalid format",
"upstreamName", upstreamIDPConfig.GetName(),
"issClaim", upstreamIssuer,
)
return "", "", httperr.New(http.StatusUnprocessableEntity, "issuer claim in upstream ID token has invalid format")
}
subjectAsInterface, ok := idTokenClaims[oidc.IDTokenSubjectClaim]
if !ok {
plog.Warning(
"no subject claim in upstream ID token",
"upstreamName", upstreamIDPConfig.GetName(),
)
return "", "", httperr.New(http.StatusUnprocessableEntity, "no subject claim in upstream ID token")
}
upstreamSubject, ok := subjectAsInterface.(string)
if !ok {
plog.Warning(
"subject claim in upstream ID token has invalid format",
"upstreamName", upstreamIDPConfig.GetName(),
)
return "", "", httperr.New(http.StatusUnprocessableEntity, "subject claim in upstream ID token has invalid format")
}
subject := fmt.Sprintf("%s?%s=%s", upstreamIssuerAsString, oidc.IDTokenSubjectClaim, upstreamSubject)
usernameClaim := upstreamIDPConfig.GetUsernameClaim()
if usernameClaim == "" {
return subject, subject, nil
}
usernameAsInterface, ok := idTokenClaims[usernameClaim]
if !ok {
plog.Warning(
"no username claim in upstream ID token",
"upstreamName", upstreamIDPConfig.GetName(),
"configuredUsernameClaim", upstreamIDPConfig.GetUsernameClaim(),
"usernameClaim", usernameClaim,
)
return "", "", httperr.New(http.StatusUnprocessableEntity, "no username claim in upstream ID token")
}
username, ok := usernameAsInterface.(string)
if !ok {
plog.Warning(
"username claim in upstream ID token has invalid format",
"upstreamName", upstreamIDPConfig.GetName(),
"configuredUsernameClaim", upstreamIDPConfig.GetUsernameClaim(),
"usernameClaim", usernameClaim,
)
return "", "", httperr.New(http.StatusUnprocessableEntity, "username claim in upstream ID token has invalid format")
}
return subject, username, nil
}
func getGroupsFromUpstreamIDToken(
upstreamIDPConfig provider.UpstreamOIDCIdentityProviderI,
idTokenClaims map[string]interface{},
) (interface{}, error) {
groupsClaim := upstreamIDPConfig.GetGroupsClaim()
if groupsClaim == "" {
return nil, nil
}
groupsAsInterface, ok := idTokenClaims[groupsClaim]
if !ok {
plog.Warning(
"no groups claim in upstream ID token",
"upstreamName", upstreamIDPConfig.GetName(),
"configuredGroupsClaim", upstreamIDPConfig.GetGroupsClaim(),
"groupsClaim", groupsClaim,
)
return nil, nil // the upstream IDP may have omitted the claim if the user has no groups
}
groupsAsArray, okAsArray := groupsAsInterface.([]string)
groupsAsString, okAsString := groupsAsInterface.(string)
if !okAsArray && !okAsString {
plog.Warning(
"groups claim in upstream ID token has invalid format",
"upstreamName", upstreamIDPConfig.GetName(),
"configuredGroupsClaim", upstreamIDPConfig.GetGroupsClaim(),
"groupsClaim", groupsClaim,
)
return nil, httperr.New(http.StatusUnprocessableEntity, "groups claim in upstream ID token has invalid format")
}
if okAsArray {
return groupsAsArray, nil
}
return groupsAsString, nil
}
func makeDownstreamSession(subject string, username string, groups interface{}) *openid.DefaultSession {
now := time.Now().UTC()
openIDSession := &openid.DefaultSession{
Claims: &jwt.IDTokenClaims{
Subject: subject,
RequestedAt: now,
AuthTime: now,
},
}
openIDSession.Claims.Extra = map[string]interface{}{
oidc.DownstreamUsernameClaim: username,
}
if groups != nil {
openIDSession.Claims.Extra[oidc.DownstreamGroupsClaim] = groups
}
return openIDSession
}