build: package CLI with pinned producer verifier

Assistant: codex
Assistant-Model: gpt-6-astra
Assistant-Session: 01a140c4-354a-7823-8f0d-8f717397f786

scripts/install_release_bundle.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+"""Install one reviewed CLI bundle offline into a new owner-controlled prefix."""
+import argparse
+import hashlib
+import json
+from pathlib import Path
+import platform
+import shutil
+import subprocess
+import sys
+
+
+def digest(path):
+    return hashlib.sha256(path.read_bytes()).hexdigest()
+
+
+def install(bundle, prefix, expected_manifest, python, uv):
+    manifest_path = bundle / "manifest.json"
+    if digest(manifest_path) != expected_manifest:
+        raise ValueError("bundle manifest differs from reviewed digest")
+    manifest = json.loads(manifest_path.read_text())
+    if manifest["schema"] != "secrets-engine.cli-bundle.v1":
+        raise ValueError("unsupported bundle")
+    if manifest['system'] != platform.system() or manifest['machine'] != platform.machine():
+        raise ValueError("bundle platform differs from installer host")
+    expected_files = set(manifest['artifacts']) | {'manifest.json'}
+    actual_files = {str(p.relative_to(bundle)) for p in bundle.rglob('*') if p.is_file()}
+    if actual_files != expected_files:
+        raise ValueError("bundle file set differs")
+    for name, expected in manifest['artifacts'].items():
+        relative = Path(name)
+        if relative.is_absolute() or '..' in relative.parts:
+            raise ValueError("invalid artifact path")
+        artifact = bundle / relative
+        if any(parent.is_symlink() for parent in (artifact,*artifact.parents)) or digest(artifact) != expected:
+            raise ValueError("bundle artifact missing or changed")
+    # Reserve once; never replace an installed prefix or follow an existing link.
+    prefix.mkdir(mode=0o700, parents=False, exist_ok=False)
+    try:
+        subprocess.run([uv,'--no-config','venv','--python',python,'--no-python-downloads',str(prefix/'venv')],check=True)
+        subprocess.run([uv,'--no-config','pip','install','--python',str(prefix/'venv/bin/python'),
+                        '--no-index','--find-links',str(bundle/'wheels'),str(bundle/manifest['wheel'])],check=True)
+        (prefix/'libexec').mkdir(mode=0o700)
+        helper=prefix/'libexec/secrets-engine-pdp-verify'
+        shutil.copyfile(bundle/'bin/secrets-engine-pdp-verify',helper);helper.chmod(0o700)
+        (prefix/'bin').mkdir(mode=0o700)
+        launcher=prefix/'bin/secrets-engine'
+        # An absolute venv interpreter fixes the installed dependency environment.
+        launcher.write_text('#!'+str(prefix/'venv/bin/python')+'\n'+(bundle/'release_cli.py').read_text())
+        launcher.chmod(0o700)
+        receipt={"schema":"secrets-engine.cli-install.v1","manifest_sha256":expected_manifest,
+                 "helper_sha256":digest(helper),"launcher_sha256":digest(launcher),"prefix":str(prefix),
+                 "admission":"artifact integrity only; trust and keys not admitted"}
+        (prefix/'install-receipt.json').write_text(json.dumps(receipt,sort_keys=True,indent=2)+'\n')
+        return receipt
+    except BaseException:
+        # Preserve a failed prefix as evidence; never retry into a partial install.
+        (prefix/'INSTALL-FAILED').write_text('Incomplete installation; use a new prefix.\n')
+        raise
+
+
+def main():
+    parser=argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('--bundle',type=Path,default=Path(__file__).resolve().parent)
+    parser.add_argument('--prefix',type=Path,required=True)
+    parser.add_argument('--manifest-sha256',required=True)
+    parser.add_argument('--python',default=sys.executable)
+    parser.add_argument('--uv',default='uv')
+    args=parser.parse_args()
+    try:
+        if not args.prefix.is_absolute() or args.prefix.parent.is_symlink():
+            raise ValueError('prefix must be absolute with an admitted parent')
+        receipt=install(args.bundle.resolve(),args.prefix,args.manifest_sha256,args.python,args.uv)
+        print(json.dumps(receipt,sort_keys=True))
+    except (OSError,ValueError,KeyError,subprocess.SubprocessError) as exc:
+        print('bundle install refused: '+str(exc),file=sys.stderr)
+        return 1
+    return 0
+
+
+if __name__=='__main__':
+    raise SystemExit(main())