Prepare verified Sargo packages and independent boot recovery

tundra/tools/export-sargo-recovery.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: MPL-2.0
+"""Export the qualified original boot backup and a standalone restoration tool.
+
+The kit is private and specific to one phone. Keep it outside the project and
+do not upload it as a release. Exporting performs no phone operations.
+"""
+import argparse
+import importlib.util
+import json
+import os
+from pathlib import Path
+import shutil
+from tundra import ROOT, digest
+
+
+def load(name, path):
+    spec = importlib.util.spec_from_file_location(name, path)
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+def export(plan, output):
+    output = Path(output).absolute()
+    if output.exists() or output.is_symlink():
+        raise ValueError('Recovery output exists; keep the existing backup')
+    backup = Path(plan['backupDirectory'])
+    from boot_backup import verify
+    manifest = verify(backup)
+    if digest(backup/'manifest.json') != plan['backupManifestSha256']:
+        raise ValueError('Backup manifest changed')
+    output.mkdir(mode=0o700)
+    marker = output/'.incomplete'
+    marker.write_text('Recovery export incomplete\n')
+    shutil.copyfile(backup/'boot_a.img', output/'boot_a.img')
+    (output/'boot_a.img').chmod(0o600)
+    tool = ROOT/'tools/restore-sargo.py'
+    shutil.copyfile(tool, output/tool.name)
+    (output/tool.name).chmod(0o700)
+    recovery = {'schema': 1, 'device': 'sargo', 'partition': 'boot_a', 'slot': 'a',
+                'serialSha256': plan['serialSha256'], 'image': 'boot_a.img',
+                'bytes': manifest['files']['boot_a.img']['bytes'],
+                'imageSha256': manifest['files']['boot_a.img']['sha256'],
+                'backupManifestSha256': plan['backupManifestSha256'],
+                'restoreToolSha256': digest(tool), 'private': True,
+                'scope': 'Original qualified boot_a only; not a userdata backup or a generic ROM'}
+    (output/'recovery.json').write_text(json.dumps(recovery, indent=2)+'\n')
+    load('restore_check', tool).checked_kit(output)
+    marker.unlink()
+    return output
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--output', type=Path, required=True)
+    args = parser.parse_args()
+    os.umask(0o077)
+    plan = load('backup_plan', ROOT/'tools/test-sargo-boot.py').checked_backup_plan()
+    print(export(plan, args.output))
+    print('Keep this private kit on another disk. Its boot image belongs only to this phone.')
+
+
+if __name__ == '__main__':
+    main()