zitadel/internal/api/oidc/token_exchange.go
Tim Möhlmann 6398349c24
feat(oidc): token exchange impersonation (#7516)
* add token exchange feature flag

* allow setting reason and actor to access tokens

* impersonation

* set token types and scopes in response

* upgrade oidc to working draft state

* fix tests

* audience and scope validation

* id toke and jwt as input

* return id tokens

* add grant type  token exchange to app config

* add integration tests

* check and deny actors in api calls

* fix instance setting tests by triggering projection on write and cleanup

* insert sleep statements again

* solve linting issues

* add translations

* pin oidc v3.15.0

* resolve comments, add event translation

* fix refreshtoken test

* use ValidateAuthReqScopes from oidc

* apparently the linter can't make up its mind

* persist actor thru refresh tokens and check in tests

* remove unneeded triggers
2024-03-20 10:18:46 +00:00

348 lines
14 KiB
Go

package oidc
import (
"context"
"slices"
"time"
"github.com/zitadel/oidc/v3/pkg/crypto"
"github.com/zitadel/oidc/v3/pkg/oidc"
"github.com/zitadel/oidc/v3/pkg/op"
"github.com/zitadel/zitadel/internal/api/authz"
"github.com/zitadel/zitadel/internal/domain"
"github.com/zitadel/zitadel/internal/telemetry/tracing"
"github.com/zitadel/zitadel/internal/zerrors"
)
const (
UserIDTokenType oidc.TokenType = "urn:zitadel:params:oauth:token-type:user_id"
// TokenTypeNA is set when the returned Token Exchange access token value can't be used as an access token.
// For example, when it is an ID Token.
// See [RFC 8693, section 2.2.1, token_type](https://www.rfc-editor.org/rfc/rfc8693#section-2.2.1)
TokenTypeNA = "N_A"
)
func init() {
oidc.AllTokenTypes = append(oidc.AllTokenTypes, UserIDTokenType)
}
func (s *Server) TokenExchange(ctx context.Context, r *op.ClientRequest[oidc.TokenExchangeRequest]) (_ *op.Response, err error) {
resp, err := s.tokenExchange(ctx, r)
if err != nil {
return nil, oidcError(err)
}
return resp, nil
}
func (s *Server) tokenExchange(ctx context.Context, r *op.ClientRequest[oidc.TokenExchangeRequest]) (_ *op.Response, err error) {
ctx, span := tracing.NewSpan(ctx)
defer func() { span.EndWithError(err) }()
if !authz.GetFeatures(ctx).TokenExchange {
return nil, zerrors.ThrowPreconditionFailed(nil, "OIDC-oan4I", "Errors.TokenExchange.FeatureDisabled")
}
if len(r.Data.Resource) > 0 {
return nil, oidc.ErrInvalidTarget().WithDescription("resource parameter not supported")
}
client, ok := r.Client.(*Client)
if !ok {
// not supposed to happen, but just preventing a panic if it does.
return nil, zerrors.ThrowInternal(nil, "OIDC-eShi5", "Error.Internal")
}
subjectToken, err := s.verifyExchangeToken(ctx, client, r.Data.SubjectToken, r.Data.SubjectTokenType, oidc.AllTokenTypes...)
if err != nil {
return nil, oidc.ErrInvalidRequest().WithParent(err).WithDescription("subject_token invalid")
}
actorToken := subjectToken // see [createExchangeTokens] comment.
if subjectToken.tokenType == UserIDTokenType || subjectToken.tokenType == oidc.JWTTokenType || r.Data.ActorToken != "" {
if !authz.GetInstance(ctx).EnableImpersonation() {
return nil, zerrors.ThrowPermissionDenied(nil, "OIDC-Fae5w", "Errors.TokenExchange.Impersonation.PolicyDisabled")
}
actorToken, err = s.verifyExchangeToken(ctx, client, r.Data.ActorToken, r.Data.ActorTokenType, oidc.AccessTokenType, oidc.IDTokenType, oidc.RefreshTokenType)
if err != nil {
return nil, oidc.ErrInvalidRequest().WithParent(err).WithDescription("actor_token invalid")
}
ctx = authz.SetCtxData(ctx, authz.CtxData{
UserID: actorToken.userID,
OrgID: actorToken.resourceOwner,
})
}
audience, err := validateTokenExchangeAudience(r.Data.Audience, subjectToken.audience, actorToken.audience)
if err != nil {
return nil, err
}
scopes, err := validateTokenExchangeScopes(client, r.Data.Scopes, subjectToken.scopes, actorToken.scopes)
if err != nil {
return nil, err
}
resp, err := s.createExchangeTokens(ctx, r.Data.RequestedTokenType, client, subjectToken, actorToken, audience, scopes)
if err != nil {
return nil, err
}
return op.NewResponse(resp), nil
}
// verifyExchangeToken verifies the passed token based on the token type. It is safe to pass both from the request as-is.
// A list of allowed token types must be passed to determine which types are trusted at a particular stage of the token exchange.
func (s *Server) verifyExchangeToken(ctx context.Context, client *Client, token string, tokenType oidc.TokenType, allowed ...oidc.TokenType) (*exchangeToken, error) {
if token == "" {
return nil, zerrors.ThrowInvalidArgument(nil, "OIDC-lei0O", "Errors.TokenExchange.Token.Missing")
}
if tokenType == "" {
return nil, zerrors.ThrowInvalidArgument(nil, "OIDC-sei9V", "Errors.TokenExchange.Token.TypeMissing")
}
if !slices.Contains(allowed, tokenType) {
return nil, zerrors.ThrowInvalidArgument(nil, "OIDC-OZ1ie", "Errors.TokenExchange.Token.TypeNotAllowed")
}
switch tokenType {
case oidc.AccessTokenType:
token, err := s.verifyAccessToken(ctx, token)
if err != nil {
return nil, zerrors.ThrowPermissionDenied(err, "OIDC-Osh3t", "Errors.TokenExchange.Token.Invalid")
}
if token.isPAT {
if err = s.assertClientScopesForPAT(ctx, token, client.GetID(), client.client.ProjectID); err != nil {
return nil, err
}
}
return accessToExchangeToken(token, op.IssuerFromContext(ctx)), nil
case oidc.IDTokenType:
verifier := op.NewIDTokenHintVerifier(op.IssuerFromContext(ctx), s.idTokenHintKeySet)
claims, err := op.VerifyIDTokenHint[*oidc.IDTokenClaims](ctx, token, verifier)
if err != nil {
return nil, zerrors.ThrowPermissionDenied(err, "OIDC-Rei0f", "Errors.TokenExchange.Token.Invalid")
}
resourceOwner, ok := claims.Claims[ClaimResourceOwnerID].(string)
if !ok || resourceOwner == "" {
user, err := s.query.GetUserByID(ctx, false, token)
if err != nil {
return nil, zerrors.ThrowPermissionDenied(err, "OIDC-aD0Oo", "Errors.TokenExchange.Token.Invalid")
}
resourceOwner = user.ResourceOwner
}
return idTokenClaimsToExchangeToken(claims, resourceOwner), nil
case oidc.JWTTokenType:
resourceOwner := new(string)
verifier := op.NewJWTProfileVerifierKeySet(keySetMap(client.client.PublicKeys), op.IssuerFromContext(ctx), time.Hour, client.client.ClockSkew, s.jwtProfileUserCheck(ctx, resourceOwner))
jwt, err := op.VerifyJWTAssertion(ctx, token, verifier)
if err != nil {
return nil, zerrors.ThrowPermissionDenied(err, "OIDC-eiS6o", "Errors.TokenExchange.Token.Invalid")
}
return jwtToExchangeToken(jwt, *resourceOwner), nil
case UserIDTokenType:
user, err := s.query.GetUserByID(ctx, false, token)
if err != nil {
return nil, zerrors.ThrowPermissionDenied(err, "OIDC-Nee6r", "Errors.TokenExchange.Token.Invalid")
}
return userToExchangeToken(user), nil
case oidc.RefreshTokenType:
fallthrough
default:
return nil, zerrors.ThrowInvalidArgument(nil, "OIDC-oda4R", "Errors.TokenExchange.Token.TypeNotSupported")
}
}
func (s *Server) jwtProfileUserCheck(ctx context.Context, resourceOwner *string) op.JWTProfileVerifierOption {
return op.SubjectCheck(func(request *oidc.JWTTokenRequest) error {
user, err := s.query.GetUserByID(ctx, false, request.Subject)
if err != nil {
return zerrors.ThrowPermissionDenied(err, "OIDC-Nee6r", "Errors.TokenExchange.Token.Invalid")
}
*resourceOwner = user.ResourceOwner
return nil
})
}
func validateTokenExchangeScopes(client *Client, requestedScopes, subjectScopes, actorScopes []string) ([]string, error) {
// Scope always has 1 empty string is the space delimited array was an empty string.
scopes := slices.DeleteFunc(requestedScopes, func(s string) bool {
return s == ""
})
if len(scopes) == 0 {
scopes = subjectScopes
}
if len(scopes) == 0 {
scopes = actorScopes
}
return op.ValidateAuthReqScopes(client, scopes)
}
func validateTokenExchangeAudience(requestedAudience, subjectAudience, actorAudience []string) ([]string, error) {
if len(requestedAudience) == 0 {
if len(subjectAudience) > 0 {
return subjectAudience, nil
}
if len(actorAudience) > 0 {
return actorAudience, nil
}
}
if slices.Equal(requestedAudience, subjectAudience) || slices.Equal(requestedAudience, actorAudience) {
return requestedAudience, nil
}
//nolint:gocritic
allowedAudience := append(subjectAudience, actorAudience...)
for _, a := range requestedAudience {
if !slices.Contains(allowedAudience, a) {
return nil, oidc.ErrInvalidTarget().WithDescription("audience %q not found in subject or actor token", a)
}
}
return requestedAudience, nil
}
// createExchangeTokens prepares the final tokens to be returned to the client.
// The subjectToken is used to set the new token's subject and resource owner.
// The actorToken is used to set the new token's auth time AMR and actor.
// Both tokens may point to the same object (subjectToken) in case of a regular Token Exchange.
// When the subject and actor Tokens point to different objects, the new tokens will be for impersonation / delegation.
func (s *Server) createExchangeTokens(ctx context.Context, tokenType oidc.TokenType, client *Client, subjectToken, actorToken *exchangeToken, audience, scopes []string) (_ *oidc.TokenExchangeResponse, err error) {
var (
userInfo *oidc.UserInfo
signingKey op.SigningKey
)
if slices.Contains(scopes, oidc.ScopeOpenID) || tokenType == oidc.JWTTokenType || tokenType == oidc.IDTokenType {
projectID := client.client.ProjectID
userInfo, err = s.userInfo(ctx, subjectToken.userID, projectID, scopes, []string{projectID})
if err != nil {
return nil, err
}
signingKey, err = s.Provider().Storage().SigningKey(ctx)
if err != nil {
return nil, err
}
}
resp := &oidc.TokenExchangeResponse{
Scopes: scopes,
}
reason := domain.TokenReasonExchange
actor := actorToken.actor
if subjectToken != actorToken {
reason = domain.TokenReasonImpersonation
actor = actorToken.nestedActor()
}
switch tokenType {
case oidc.AccessTokenType, "":
resp.AccessToken, resp.RefreshToken, resp.ExpiresIn, err = s.createExchangeAccessToken(ctx, client, subjectToken.resourceOwner, subjectToken.userID, audience, scopes, actorToken.authMethods, actorToken.authTime, reason, actor)
resp.TokenType = oidc.BearerToken
resp.IssuedTokenType = oidc.AccessTokenType
case oidc.JWTTokenType:
resp.AccessToken, resp.RefreshToken, resp.ExpiresIn, err = s.createExchangeJWT(ctx, signingKey, client, subjectToken.resourceOwner, subjectToken.userID, audience, scopes, actorToken.authMethods, actorToken.authTime, reason, actor, userInfo.Claims)
resp.TokenType = oidc.BearerToken
resp.IssuedTokenType = oidc.JWTTokenType
case oidc.IDTokenType:
resp.AccessToken, resp.ExpiresIn, err = s.createExchangeIDToken(ctx, signingKey, client, subjectToken.userID, "", audience, userInfo, actorToken.authMethods, actorToken.authTime, reason, actor)
resp.TokenType = TokenTypeNA
resp.IssuedTokenType = oidc.IDTokenType
case oidc.RefreshTokenType, UserIDTokenType:
fallthrough
default:
err = zerrors.ThrowInvalidArgument(nil, "OIDC-wai5E", "Errors.TokenExchange.Token.TypeNotSupported")
}
if err != nil {
return nil, err
}
if slices.Contains(scopes, oidc.ScopeOpenID) && tokenType != oidc.IDTokenType {
resp.IDToken, _, err = s.createExchangeIDToken(ctx, signingKey, client, subjectToken.userID, resp.AccessToken, audience, userInfo, actorToken.authMethods, actorToken.authTime, reason, actor)
if err != nil {
return nil, err
}
}
return resp, nil
}
func (s *Server) createExchangeAccessToken(ctx context.Context, client *Client, resourceOwner, userID string, audience, scopes []string, authMethods []domain.UserAuthMethodType, authTime time.Time, reason domain.TokenReason, actor *domain.TokenActor) (accessToken string, refreshToken string, exp uint64, err error) {
tokenInfo, refreshToken, err := s.createAccessTokenCommands(ctx, client, resourceOwner, userID, audience, scopes, authMethods, authTime, reason, actor)
if err != nil {
return "", "", 0, err
}
accessToken, err = op.CreateBearerToken(tokenInfo.TokenID, userID, s.Provider().Crypto())
if err != nil {
return "", "", 0, err
}
return accessToken, refreshToken, timeToOIDCExpiresIn(tokenInfo.Expiration), nil
}
func (s *Server) createExchangeJWT(ctx context.Context, signingKey op.SigningKey, client *Client, resourceOwner, userID string, audience, scopes []string, authMethods []domain.UserAuthMethodType, authTime time.Time, reason domain.TokenReason, actor *domain.TokenActor, privateClaims map[string]any) (accessToken string, refreshToken string, exp uint64, err error) {
tokenInfo, refreshToken, err := s.createAccessTokenCommands(ctx, client, resourceOwner, userID, audience, scopes, authMethods, authTime, reason, actor)
if err != nil {
return "", "", 0, err
}
expTime := tokenInfo.Expiration.Add(client.ClockSkew())
claims := oidc.NewAccessTokenClaims(op.IssuerFromContext(ctx), userID, tokenInfo.Audience, expTime, tokenInfo.TokenID, client.GetID(), client.ClockSkew())
claims.Actor = actorDomainToClaims(tokenInfo.Actor)
claims.Claims = privateClaims
signer, err := op.SignerFromKey(signingKey)
if err != nil {
return "", "", 0, err
}
accessToken, err = crypto.Sign(claims, signer)
if err != nil {
return "", "", 0, nil
}
return accessToken, refreshToken, timeToOIDCExpiresIn(expTime), nil
}
func (s *Server) createExchangeIDToken(ctx context.Context, signingKey op.SigningKey, client *Client, userID, accessToken string, audience []string, userInfo *oidc.UserInfo, authMethods []domain.UserAuthMethodType, authTime time.Time, reason domain.TokenReason, actor *domain.TokenActor) (idToken string, exp uint64, err error) {
expTime := time.Now().Add(client.IDTokenLifetime()).Add(client.ClockSkew())
claims := oidc.NewIDTokenClaims(op.IssuerFromContext(ctx), userID, audience, expTime, authTime, "", "", AuthMethodTypesToAMR(authMethods), client.GetID(), client.ClockSkew())
claims.Actor = actorDomainToClaims(actor)
claims.SetUserInfo(userInfo)
if accessToken != "" {
claims.AccessTokenHash, err = oidc.ClaimHash(accessToken, signingKey.SignatureAlgorithm())
if err != nil {
return "", 0, err
}
}
signer, err := op.SignerFromKey(signingKey)
if err != nil {
return "", 0, err
}
idToken, err = crypto.Sign(claims, signer)
return idToken, timeToOIDCExpiresIn(expTime), err
}
func timeToOIDCExpiresIn(exp time.Time) uint64 {
return uint64(time.Until(exp) / time.Second)
}
func (s *Server) createAccessTokenCommands(ctx context.Context, client *Client, resourceOwner, userID string, audience, scopes []string, authMethods []domain.UserAuthMethodType, authTime time.Time, reason domain.TokenReason, actor *domain.TokenActor) (tokenInfo *domain.Token, refreshToken string, err error) {
settings := client.client.Settings
if slices.Contains(scopes, oidc.ScopeOfflineAccess) {
return s.command.AddAccessAndRefreshToken(
ctx, resourceOwner, "", client.GetID(), userID, "", audience, scopes, AuthMethodTypesToAMR(authMethods),
settings.AccessTokenLifetime, settings.RefreshTokenIdleExpiration, settings.RefreshTokenExpiration,
authTime, reason, actor,
)
}
tokenInfo, err = s.command.AddUserToken(
ctx, resourceOwner, "", client.GetID(), userID, audience, scopes, AuthMethodTypesToAMR(authMethods),
settings.AccessTokenLifetime,
authTime, reason, actor,
)
return tokenInfo, "", err
}