Repository: zitadel/oidc
Pull request #664 (2024-10-09 16:05:53)

fix(op): add scope to access token scope
This attempts to solve [Issue 660](https://github.com/zitadel/oidc/issues/660).

All the details are there. TLDR; Access Token response is not compliant with OAuth 2.0. We decided to _always_ return the `scope` property in the Access Token response to comply with [RFC 6749](https://datatracker.ietf.org/doc/html/rfc6749#section-3.3).

The implementation consists of getting the scope from the token request, which should be already containing only the scopes that are granted.

### Definition of Ready

- [ ] I am happy with the code
- [x] Short description of the feature/issue is added in the pr description
- [x] PR is linked to the corresponding user story
- [ ] Acceptance criteria are met
- [ ] All open todos and follow ups are defined in a new ticket and justified
- [ ] Deviations from the acceptance criteria and design are agreed with the PO and documented.
- [ ] No debug or dead code
- [ ] My code has no repetitions
- [ ] Critical parts are tested automatically
- [ ] Where possible E2E tests are implemented
- [ ] Documentation/examples are up-to-date
- [ ] All non-functional requirements are met
- [ ] Functionality of the acceptance criteria is checked manually on the dev system.

### Further improvements

In my opinion, a more elegant solution would be to strictly adhere with the protocol and only return the scope if has been modified from the request. If compliant, clients could assume all scopes are given by the absence of the `scope` property in the token response, this would avoid parsing the response scope. However, this change would probably cause a breaking change in the exported package, so this solution is good for now.

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All modified and coverable lines are covered by tests :white_check_mark:
> Project coverage is 60.98%. Comparing base [(`0992c5f`)](https://app.codecov.io/gh/zitadel/oidc/commit/0992c5f3ce793c265c82993cf17fcb7c5a7e6cdf?dropdown=coverage&el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zitadel) to head [(`ee6e4ac`)](https://app.codecov.io/gh/zitadel/oidc/commit/ee6e4acb2aa42ed22266a1f46f27ca1563bb9979?dropdown=coverage&el=desc&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zitadel).
> Report is 104 commits behind head on main.

<details><summary>Additional details and impacted files</summary>


```diff
@@            Coverage Diff             @@
##             main     #664      +/-   ##
==========================================
+ Coverage   60.06%   60.98%   +0.92%     
==========================================
  Files          80       81       +1     
  Lines        6998     7462     +464     
==========================================
+ Hits         4203     4551     +348     
- Misses       2498     2601     +103     
- Partials      297      310      +13     
```

</details>

[:umbrella: View full report in Codecov by Sentry](https://app.codecov.io/gh/zitadel/oidc/pull/664?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=zitadel).   
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Patch:
diff --git a/pkg/oidc/token.go b/pkg/oidc/token.go
index e57d91e..d2b6f6d 100644
--- a/pkg/oidc/token.go
+++ b/pkg/oidc/token.go
@@ -230,12 +230,13 @@ func (c *ActorClaims) UnmarshalJSON(data []byte) error {
 }
 
 type AccessTokenResponse struct {
-	AccessToken  string `json:"access_token,omitempty" schema:"access_token,omitempty"`
-	TokenType    string `json:"token_type,omitempty" schema:"token_type,omitempty"`
-	RefreshToken string `json:"refresh_token,omitempty" schema:"refresh_token,omitempty"`
-	ExpiresIn    uint64 `json:"expires_in,omitempty" schema:"expires_in,omitempty"`
-	IDToken      string `json:"id_token,omitempty" schema:"id_token,omitempty"`
-	State        string `json:"state,omitempty" schema:"state,omitempty"`
+	AccessToken  string              `json:"access_token,omitempty" schema:"access_token,omitempty"`
+	TokenType    string              `json:"token_type,omitempty" schema:"token_type,omitempty"`
+	RefreshToken string              `json:"refresh_token,omitempty" schema:"refresh_token,omitempty"`
+	ExpiresIn    uint64              `json:"expires_in,omitempty" schema:"expires_in,omitempty"`
+	IDToken      string              `json:"id_token,omitempty" schema:"id_token,omitempty"`
+	State        string              `json:"state,omitempty" schema:"state,omitempty"`
+	Scope        SpaceDelimitedArray `json:"scope,omitempty" schema:"scope,omitempty"`
 }
 
 type JWTProfileAssertionClaims struct {
diff --git a/pkg/op/device.go b/pkg/op/device.go
index 11638b0..3de271a 100644
--- a/pkg/op/device.go
+++ b/pkg/op/device.go
@@ -344,6 +344,7 @@ func CreateDeviceTokenResponse(ctx context.Context, tokenRequest TokenRequest, c
 		RefreshToken: refreshToken,
 		TokenType:    oidc.BearerToken,
 		ExpiresIn:    uint64(validity.Seconds()),
+		Scope:        tokenRequest.GetScopes(),
 	}
 
 	// TODO(v4): remove type assertion
diff --git a/pkg/op/token.go b/pkg/op/token.go
index b45789b..61d7b2f 100644
--- a/pkg/op/token.go
+++ b/pkg/op/token.go
@@ -65,6 +65,7 @@ func CreateTokenResponse(ctx context.Context, request IDTokenRequest, client Cli
 		TokenType:    oidc.BearerToken,
 		ExpiresIn:    exp,
 		State:        state,
+		Scope:        request.GetScopes(),
 	}, nil
 }
 
diff --git a/pkg/op/token_client_credentials.go b/pkg/op/token_client_credentials.go
index 7f1debe..63dcc79 100644
--- a/pkg/op/token_client_credentials.go
+++ b/pkg/op/token_client_credentials.go
@@ -120,5 +120,6 @@ func CreateClientCredentialsTokenResponse(ctx context.Context, tokenRequest Toke
 		AccessToken: accessToken,
 		TokenType:   oidc.BearerToken,
 		ExpiresIn:   uint64(validity.Seconds()),
+		Scope:       tokenRequest.GetScopes(),
 	}, nil
 }
diff --git a/pkg/op/token_jwt_profile.go b/pkg/op/token_jwt_profile.go
index 96ce1ed..d1a7ff5 100644
--- a/pkg/op/token_jwt_profile.go
+++ b/pkg/op/token_jwt_profile.go
@@ -89,6 +89,7 @@ func CreateJWTTokenResponse(ctx context.Context, tokenRequest TokenRequest, crea
 		AccessToken: accessToken,
 		TokenType:   oidc.BearerToken,
 		ExpiresIn:   uint64(validity.Seconds()),
+		Scope:       tokenRequest.GetScopes(),
 	}, nil
 }
 


Test patch:
diff --git a/pkg/op/op_test.go b/pkg/op/op_test.go
index 83032d4..9a4a624 100644
--- a/pkg/op/op_test.go
+++ b/pkg/op/op_test.go
@@ -232,7 +232,7 @@ func TestRoutes(t *testing.T) {
 				"scope":      oidc.SpaceDelimitedArray{oidc.ScopeOpenID, oidc.ScopeOfflineAccess}.String(),
 			},
 			wantCode: http.StatusOK,
-			contains: []string{`{"access_token":"`, `","token_type":"Bearer","expires_in":299}`},
+			contains: []string{`{"access_token":"`, `","token_type":"Bearer","expires_in":299,"scope":"openid offline_access"}`},
 		},
 		{
 			// This call will fail. A successful test is already
diff --git a/pkg/op/server_http_routes_test.go b/pkg/op/server_http_routes_test.go
index 2c83ad3..1bfb32b 100644
--- a/pkg/op/server_http_routes_test.go
+++ b/pkg/op/server_http_routes_test.go
@@ -145,7 +145,7 @@ func TestServerRoutes(t *testing.T) {
 				"assertion":  jwtProfileToken,
 			},
 			wantCode: http.StatusOK,
-			contains: []string{`{"access_token":`, `"token_type":"Bearer","expires_in":299}`},
+			contains: []string{`{"access_token":`, `"token_type":"Bearer","expires_in":299,"scope":"openid"}`},
 		},
 		{
 			name:      "Token exchange",
@@ -174,7 +174,7 @@ func TestServerRoutes(t *testing.T) {
 				"scope":      oidc.SpaceDelimitedArray{oidc.ScopeOpenID, oidc.ScopeOfflineAccess}.String(),
 			},
 			wantCode: http.StatusOK,
-			contains: []string{`{"access_token":"`, `","token_type":"Bearer","expires_in":299}`},
+			contains: []string{`{"access_token":"`, `","token_type":"Bearer","expires_in":299,"scope":"openid offline_access"}`},
 		},
 		{
 			// This call will fail. A successful test is already