fix: unset NOTATION_USERNAME and NOTATION_PASSWORD to avoid leaking credentials to plugin

cmd/notation/main.go

@@ -26,6 +26,12 @@ func main() {
 		Use:          "notation",
 		Short:        "Notation - a tool to sign and verify artifacts",
 		SilenceUsage: true,
+		PersistentPreRun: func(cmd *cobra.Command, args []string) {
+			// unset registry credentials after read the value from environment
+			// to avoid leaking credentials
+			os.Unsetenv(defaultUsernameEnv)
+			os.Unsetenv(defaultPasswordEnv)
+		},
 	}
 	cmd.AddCommand(
 		signCommand(nil),

cmd/notation/main_test.go

@@ -0,0 +1,39 @@
+// Copyright The Notary Project Authors.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"os"
+	"testing"
+)
+
+func Test_UnsetEnvCredential(t *testing.T) {
+	const notationUsername = "NOTATION_USERNAME"
+	const notationPassword = "NOTATION_PASSWORD"
+	// Set environment variables for testing
+	os.Setenv(notationUsername, "testuser")
+	os.Setenv(notationPassword, "testpassword")
+	os.Args = []string{"notation", "version"}
+
+	main()
+
+	// check credentials environment variables are unset
+	if os.Getenv(notationUsername) != "" {
+		t.Errorf("expected %s to be unset", notationUsername)
+	}
+
+	if os.Getenv(notationPassword) != "" {
+		t.Errorf("expected %s to be unset", notationPassword)
+	}
+}