feat(tools): Signierwerkzeug fuer Migrationsimages

nl_sign.py signiert/prueft W600-Images im RSA-4096-PKCS#1-v1.5-Format der alten Klyqa-Firmware (Check_OTA_Image() in qc_ssl_layer.c): SHA256 ueber die gesamte Datei, angehaengt als exakt 512 Byte - derselbe Block wie der ninlight-Trailer, daher die Ablehnung bereits getrailerter Eingaben. Unterstuetzt sowohl cryptography als auch pycryptodome/pycryptodomex als Backend. Gegen das echte Klyqa-Schluesselpaar aus ~/workspace/fw-sign bitgleich verifiziert. tools/test_host.sh haengt jetzt die Python-Tests aus tools/mkimage/tests und tools/station/tests an ctest an.
2026-09-13 03:15:08 +02:00
parent 00d5a4c532
commit e50659d954
3 changed files with 303 additions and 0 deletions
@@ -0,0 +1,86 @@
+from __future__ import annotations
+
+import subprocess
+import sys
+from pathlib import Path
+
+import pytest
+
+HERE = Path(__file__).resolve().parent
+TOOL = HERE.parent / "nl_sign.py"
+sys.path.insert(0, str(HERE.parent))
+
+import nl_sign  # noqa: E402
+
+
+@pytest.fixture(scope="module")
+def key():
+    """Ein eigener 4096-Bit-Schluessel, damit kein echter Signierschluessel in die Tests
+    gerät. Einmal pro Modul, weil das Erzeugen ein paar Sekunden dauert."""
+    return nl_sign.generate_test_key()
+
+
+def test_signature_is_512_bytes(key, tmp_path):
+    raw = b"\xa5" * 4096
+    signed = nl_sign.sign_image(raw, key.private_pem)
+    assert len(signed) == len(raw) + 512
+    assert signed[: len(raw)] == raw
+
+
+def test_signature_verifies(key):
+    raw = b"firmware" * 512
+    signed = nl_sign.sign_image(raw, key.private_pem)
+    assert nl_sign.verify_image(signed, key.public_der) is True
+
+
+def test_modified_payload_fails_verification(key):
+    raw = bytearray(b"firmware" * 512)
+    signed = bytearray(nl_sign.sign_image(bytes(raw), key.private_pem))
+    signed[17] ^= 0xFF
+    assert nl_sign.verify_image(bytes(signed), key.public_der) is False
+
+
+def test_signing_is_deterministic(key):
+    raw = b"x" * 1024
+    assert nl_sign.sign_image(raw, key.private_pem) == nl_sign.sign_image(raw, key.private_pem)
+
+
+def test_cli_roundtrip(key, tmp_path):
+    src = tmp_path / "in_gz.img"
+    dst = tmp_path / "out.img"
+    pub = tmp_path / "pub.der"
+    priv = tmp_path / "key.pem"
+    src.write_bytes(b"\x01\x02\x03" * 1000)
+    priv.write_bytes(key.private_pem)
+    pub.write_bytes(key.public_der)
+    subprocess.run([sys.executable, str(TOOL), "sign", "--key", str(priv),
+                    "--in", str(src), "--out", str(dst)], check=True)
+    assert dst.stat().st_size == src.stat().st_size + 512
+    subprocess.run([sys.executable, str(TOOL), "verify", "--pub", str(pub),
+                    "--in", str(dst)], check=True)
+
+
+def test_cli_verify_rejects_tampered(key, tmp_path):
+    src = tmp_path / "in_gz.img"
+    dst = tmp_path / "out.img"
+    pub = tmp_path / "pub.der"
+    priv = tmp_path / "key.pem"
+    src.write_bytes(b"\x07" * 2000)
+    priv.write_bytes(key.private_pem)
+    pub.write_bytes(key.public_der)
+    subprocess.run([sys.executable, str(TOOL), "sign", "--key", str(priv),
+                    "--in", str(src), "--out", str(dst)], check=True)
+    data = bytearray(dst.read_bytes())
+    data[0] ^= 0x01
+    dst.write_bytes(bytes(data))
+    r = subprocess.run([sys.executable, str(TOOL), "verify", "--pub", str(pub),
+                        "--in", str(dst)])
+    assert r.returncode != 0
+
+
+def test_refuses_already_signed_looking_input(key, tmp_path):
+    """Ein Image mit ninlight-Trailer ist ein OTA-Image, kein Rohbild - zweimal 512 Byte
+    anzuhaengen ergaebe eine Datei, die die alte Firmware ablehnt."""
+    raw = b"\x00" * 1024 + b"NINL" + b"\x01" + b"\x00" * 507
+    with pytest.raises(nl_sign.SignError):
+        nl_sign.sign_image(raw, key.private_pem)