Skip to content

fix(coderd): validate GCP instance token audience #29765

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
dylanhuff-at-coder merged 1 commit into from
Sep 24, 2026
+30 −9
Merged

fix(coderd): validate GCP instance token audience #29765

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
3 changes: 2 additions & 1 deletion coderd/coderdtest/coderdtest.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1610,10 +1610,11 @@ func RequestExternalAuthCallback(t testing.TB, providerID string, client *coders
// NewGoogleInstanceIdentity returns a metadata client and ID token validator for faking
// instance authentication for Google Cloud.
// nolint:revive
func NewGoogleInstanceIdentity(t testing.TB, instanceID string, expired bool) (*idtoken.Validator, *metadata.Client) {
func NewGoogleInstanceIdentity(t testing.TB, instanceID string, expired bool, audience string) (*idtoken.Validator, *metadata.Client) {
keyID, err := cryptorand.String(12)
require.NoError(t, err)
claims := jwt.MapClaims{
"aud": audience,
"google": map[string]interface{}{
"compute_engine": map[string]string{
"instance_id": instanceID,
Expand Down
2 changes: 1 addition & 1 deletion coderd/coderdtest/coderdtest_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ func TestNew(t *testing.T) {
workspace := coderdtest.CreateWorkspace(t, client, template.ID)
coderdtest.AwaitWorkspaceBuildJobCompleted(t, client, workspace.LatestBuild.ID)
coderdtest.AwaitWorkspaceAgents(t, client, workspace.ID)
_, _ = coderdtest.NewGoogleInstanceIdentity(t, "example", false)
_, _ = coderdtest.NewGoogleInstanceIdentity(t, "example", false, "coder")
_, _ = coderdtest.NewAWSInstanceIdentity(t, "an-instance")
}

Expand Down
3 changes: 1 addition & 2 deletions coderd/workspaceresourceauth.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -104,8 +104,7 @@ func (api *API) postWorkspaceAuthGoogleInstanceIdentity(rw http.ResponseWriter,
return
}

// We leave the audience blank. It's not important we validate who made the token.
payload, err := api.GoogleTokenValidator.Validate(ctx, req.JSONWebToken, "")
payload, err := api.GoogleTokenValidator.Validate(ctx, req.JSONWebToken, "coder")
if err != nil {
httpapi.Write(ctx, rw, http.StatusUnauthorized, codersdk.Response{
Message: "Invalid GCP identity.",
Expand Down
31 changes: 26 additions & 5 deletions coderd/workspaceresourceauth_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -291,7 +291,7 @@ func TestPostWorkspaceAuthGoogleInstanceIdentity(t *testing.T) {
t.Parallel()

instanceID := newTestInstanceID(t)
validator, metadata := coderdtest.NewGoogleInstanceIdentity(t, instanceID, true)
validator, metadata := coderdtest.NewGoogleInstanceIdentity(t, instanceID, true, "coder")
client := coderdtest.New(t, &coderdtest.Options{
GoogleTokenValidator: validator,
})
Expand All @@ -310,7 +310,7 @@ func TestPostWorkspaceAuthGoogleInstanceIdentity(t *testing.T) {
t.Parallel()

instanceID := newTestInstanceID(t)
validator, metadata := coderdtest.NewGoogleInstanceIdentity(t, instanceID, false)
validator, metadata := coderdtest.NewGoogleInstanceIdentity(t, instanceID, false, "coder")
client := coderdtest.New(t, &coderdtest.Options{
GoogleTokenValidator: validator,
})
Expand All @@ -329,24 +329,45 @@ func TestPostWorkspaceAuthGoogleInstanceIdentity(t *testing.T) {
t.Parallel()

instanceID := newTestInstanceID(t)
validator, metadata := coderdtest.NewGoogleInstanceIdentity(t, instanceID, false)
client, _ := setupInstanceIDWorkspace(t, &coderdtest.Options{
validator, metadata := coderdtest.NewGoogleInstanceIdentity(t, instanceID, false, "coder")
client, store := setupInstanceIDWorkspace(t, &coderdtest.Options{
GoogleTokenValidator: validator,
}, workspaceAgentsForInstanceID(instanceID, "dev"))
expectedAgent := requireWorkspaceAgentByInstanceIDAndName(t, store, instanceID, "dev")

ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitLong)
defer cancel()

agentClient := agentsdk.New(client.URL, agentsdk.WithGoogleInstanceIdentity("", metadata))
err := agentClient.RefreshToken(ctx)
require.NoError(t, err)
require.Equal(t, expectedAgent.AuthToken.String(), agentClient.SDK.SessionToken())
})

t.Run("ForeignAudience", func(t *testing.T) {
t.Parallel()

instanceID := newTestInstanceID(t)
validator, metadata := coderdtest.NewGoogleInstanceIdentity(t, instanceID, false, "other-service")
client, _ := setupInstanceIDWorkspace(t, &coderdtest.Options{
GoogleTokenValidator: validator,
}, workspaceAgentsForInstanceID(instanceID, "dev"))

ctx, cancel := context.WithTimeout(context.Background(), testutil.WaitLong)
defer cancel()

agentClient := agentsdk.New(client.URL, agentsdk.WithGoogleInstanceIdentity("", metadata))
err := agentClient.RefreshToken(ctx)
var apiErr *codersdk.Error
require.ErrorAs(t, err, &apiErr)
require.Equal(t, http.StatusUnauthorized, apiErr.StatusCode())
})

t.Run("Ambiguous/GoogleWithSelector", func(t *testing.T) {
t.Parallel()

instanceID := newTestInstanceID(t)
validator, metadata := coderdtest.NewGoogleInstanceIdentity(t, instanceID, false)
validator, metadata := coderdtest.NewGoogleInstanceIdentity(t, instanceID, false, "coder")
client, store := setupInstanceIDWorkspace(t, &coderdtest.Options{
GoogleTokenValidator: validator,
}, workspaceAgentsForInstanceID(instanceID, "alpha", "beta"))
Expand Down
Loading