fix(upgrade): U-01 — enforce pre-hashed minisign verification

tests/upgrade_security_test.rs

@@ -75,3 +75,36 @@ fn test_upgrade_blocks_unofficial_url_without_insecure_flag() {
         "Fehler muss Sicherheitsverstoß anzeigen: {err_msg}"
     );
 }
+
+#[test]
+fn test_u01_reject_legacy_unhashed_signature() {
+    let payload = b"Hello Sanctum Release 0.7.0 Security Testing\n";
+    let sig_text = "\
+untrusted comment: signature from minisign secret key\n\
+RUSsVphPgr8155LCucDq8RzDmWMzWElzhBmHrS5p+qJlOCGU4AQpn2F28MVPFrnoGPYEHx7/6TlKg2b45DlYuBQ0+ASeLIzMLwc=\n\
+trusted comment: timestamp:1789750897\tfile:test_payload.txt\thashed\n\
+0l7KsNJkDTo2uOKL8UAiaJOWuhwhGTVZ5fn0JFMdxXE9riYixQO9YnBpSVqz8iCDhWrz8hJBnmUrIWnaRaXVCA==\n";
+
+    // Gültige pre-hashed Signatur muss weiterhin erfolgreich geprüft werden
+    assert!(verify_minisign_signature(payload, sig_text, SANCTUM_RELEASE_PUBKEY).is_ok());
+
+    // Modifiziere die Signatur, um eine Legacy-Signatur (Ed statt ED) zu simulieren
+    // In Base64 entspricht 'ED' (0x45, 0x44) dem Präfix 'RU'
+    // 'Ed' (0x45, 0x64) entspricht in Base64 dem Präfix 'RW'
+    let lines: Vec<&str> = sig_text.lines().collect();
+    let mut sig_line = lines[1].to_string();
+    assert!(sig_line.starts_with("RU"));
+    sig_line.replace_range(0..2, "RW");
+
+    let legacy_sig_text = format!(
+        "{}\n{}\n{}\n{}\n",
+        lines[0], sig_line, lines[2], lines[3]
+    );
+
+    let res = verify_minisign_signature(payload, &legacy_sig_text, SANCTUM_RELEASE_PUBKEY);
+    assert!(
+        res.is_err(),
+        "U-01: Legacy-Signaturen (ohne Pre-Hashing) müssen strikt abgewiesen werden"
+    );
+}
+