Add check for grant type in tokenexchangehandler,

- also started writing a test for the tokenexchangehandler, skipping for
now

Signed-off-by: Ryan Richard <rrichard@vmware.com>

internal/oidc/nullstorage_test.go

@@ -27,7 +27,7 @@ func TestNullStorage_GetClient(t *testing.T) {
 				Public:        true,
 				RedirectURIs:  []string{"http://127.0.0.1/callback"},
 				ResponseTypes: []string{"code"},
-				GrantTypes:    []string{"authorization_code", "refresh_token"},
+				GrantTypes:    []string{"authorization_code", "refresh_token", "urn:ietf:params:oauth:grant-type:token-exchange"},
 				Scopes:        []string{"openid", "offline_access", "profile", "email"},
 			},
 			TokenEndpointAuthMethod: "none",

internal/oidc/oidc.go

@@ -84,8 +84,8 @@ func PinnipedCLIOIDCClient() *fosite.DefaultOpenIDConnectClient {
 			Public:        true,
 			RedirectURIs:  []string{"http://127.0.0.1/callback"},
 			ResponseTypes: []string{"code"},
-			GrantTypes:    []string{"authorization_code", "urn:ietf:params:oauth:grant-type:token-exchange"},
+			GrantTypes:    []string{"authorization_code", "refresh_token", "urn:ietf:params:oauth:grant-type:token-exchange"},
-			Scopes:        []string{coreosoidc.ScopeOpenID, coreosoidc.ScopeOfflineAccess, "profile", "email"},
+			Scopes:        []string{coreosoidc.ScopeOpenID, coreosoidc.ScopeOfflineAccess, "profile", "email", "pinniped.sts.unrestricted"},
 		},
 		TokenEndpointAuthMethod: "none",
 	}
@@ -126,12 +126,12 @@ func FositeOauth2Helper(
 			OpenIDConnectTokenStrategy: newDynamicOpenIDConnectECDSAStrategy(oauthConfig, jwksProvider),
 		},
 		nil, // hasher, defaults to using BCrypt when nil. Used for hashing client secrets.
-		TokenExchangeFactory,
 		compose.OAuth2AuthorizeExplicitFactory,
 		// compose.OAuth2RefreshTokenGrantFactory,
 		compose.OpenIDConnectExplicitFactory,
 		// compose.OpenIDConnectRefreshFactory,
 		compose.OAuth2PKCEFactory,
+		TokenExchangeFactory,
 	)
 }
 

internal/oidc/token/token_handler_test.go

@@ -206,6 +206,19 @@ var (
 			"redirect_uri":          {goodRedirectURI},
 		},
 	}
+
+	happyTokenExchangeRequest = func(audience string, subjectToken string) *http.Request {
+		return &http.Request{
+			Form: url.Values{
+				"grant_type":           {"urn:ietf:params:oauth:grant-type:token-exchange"},
+				"audience":             {audience},
+				"subject_token":        {subjectToken},
+				"subject_token_type":   {"urn:ietf:params:oauth:token-type:access_token"},
+				"requested_token_type": {"urn:ietf:params:oauth:token-type:jwt"},
+				"client_id":            {goodClient},
+			},
+		}
+	}
 )
 
 type authcodeExchangeInputs struct {
@@ -550,6 +563,55 @@ func TestTokenEndpointWhenAuthcodeIsUsedTwice(t *testing.T) {
 	}
 }
 
+func TestTokenExchange(t *testing.T) {
+	// TODO write this test
+	t.Skip()
+	tests := []struct {
+		name                       string
+		authcodeExchange           authcodeExchangeInputs
+		wantStatus                 int
+		requestedAudience          string
+		modifyTokenExchangeRequest func(r *http.Request)
+	}{
+		{
+			name: "token exchange happy path",
+			authcodeExchange: authcodeExchangeInputs{
+				modifyAuthRequest: func(authRequest *http.Request) {
+					authRequest.Form.Set("scope", "openid pinniped.sts.unrestricted")
+				},
+				wantStatus:          http.StatusOK,
+				wantBodyFields:      []string{"id_token", "access_token", "token_type", "expires_in", "scope"},
+				wantRequestedScopes: []string{"openid", "pinniped.sts.unrestricted"},
+			},
+			wantStatus: http.StatusOK,
+		},
+	}
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			subject, rsp, _, _, _ := exchangeAuthcodeForTokens(t, test.authcodeExchange)
+			var parsedResponseBody map[string]interface{}
+			require.NoError(t, json.Unmarshal(rsp.Body.Bytes(), &parsedResponseBody))
+
+			request := happyTokenExchangeRequest("foo-cluster", parsedResponseBody["access_token"].(string))
+
+			req := httptest.NewRequest("POST", "/path/shouldn't/matter", body(request.Form).ReadCloser())
+			req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+			if test.modifyTokenExchangeRequest != nil {
+				test.modifyTokenExchangeRequest(req)
+			}
+			rsp = httptest.NewRecorder()
+
+			subject.ServeHTTP(rsp, req)
+			t.Logf("response: %#v", rsp)
+			t.Logf("response body: %q", rsp.Body.String())
+
+			require.Equal(t, test.wantStatus, rsp.Code)
+			testutil.RequireEqualContentType(t, rsp.Header().Get("Content-Type"), "application/json")
+		})
+	}
+}
+
 func exchangeAuthcodeForTokens(t *testing.T, test authcodeExchangeInputs) (
 	subject http.Handler,
 	rsp *httptest.ResponseRecorder,
@@ -758,6 +820,9 @@ func simulateAuthEndpointHavingAlreadyRun(t *testing.T, authRequest *http.Reques
 	if strings.Contains(authRequest.Form.Get("scope"), "offline_access") {
 		authRequester.GrantScope("offline_access")
 	}
+	if strings.Contains(authRequest.Form.Get("scope"), "pinniped.sts.unrestricted") {
+		authRequester.GrantScope("pinniped.sts.unrestricted")
+	}
 	authResponder, err := oauthHelper.NewAuthorizeResponse(ctx, authRequester, session)
 	require.NoError(t, err)
 	return authResponder

internal/oidc/token_exchange.go

@@ -1,3 +1,6 @@
+// Copyright 2020 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
 package oidc
 
 import (
@@ -35,6 +38,9 @@ func (t *TokenExchangeHandler) HandleTokenEndpointRequest(ctx context.Context, r
 }
 
 func (t *TokenExchangeHandler) PopulateTokenEndpointResponse(ctx context.Context, requester fosite.AccessRequester, responder fosite.AccessResponder) error {
+	if !(requester.GetGrantTypes().ExactOne("urn:ietf:params:oauth:grant-type:token-exchange")) {
+		return errors.WithStack(fosite.ErrUnknownRequest)
+	}
 	params := requester.GetRequestForm()
 	accessToken := params.Get("subject_token")
 	if err := t.accessTokenStrategy.ValidateAccessToken(ctx, requester, accessToken); err != nil {
@@ -49,7 +55,7 @@ func (t *TokenExchangeHandler) PopulateTokenEndpointResponse(ctx context.Context
 		return errors.WithStack(fosite.ErrScopeNotGranted)
 	}
 	// TODO check the other requester fields
-	scopedDownRequester := fosite.NewAccessRequest(requester.GetSession())
+	scopedDownRequester := fosite.NewAccessRequest(accessTokenSession.GetSession())
 	scopedDownRequester.GrantedAudience = []string{params.Get("audience")}
 	newToken, err := t.idTokenStrategy.GenerateIDToken(ctx, scopedDownRequester)
 	if err != nil {