v0.3.3: keep the restic repo password out of argv and shell history

Security
--------
create_task.py shelled out to `midclt call cloud_backup.create '<json>'`, and that
JSON carries the restic repository password -- so it sat in the subprocess's argv,
which is world-readable via ps, for the duration of the call. That password is the
encryption key for the entire cloud backup repository.

It now talks to the middleware through truenas_api_client, the library that backs
midclt itself, so the password never leaves this process's memory. Verified on a
live box: list-tasks and list-credentials work through the new transport.

--password is also no longer required, because passing a secret as a CLI argument
writes it to shell history permanently. --password-stdin reads it from stdin, and
with neither flag the tool prompts via getpass. --password still works but warns.

Fixed
-----
uninstall.sh could leave every patch installed. It reverted by unmounting the
overlay -- but apply.sh only mounts one when the target directory is read-only. On
a writable /usr it patches the real files in place, and uninstall would remove the
boot hook, report success, and leave the patch applied. It now strips the appended
blocks from the middleware files explicitly. This also covers the case where the
overlay unmount fails.

create_task.py's __version__ had been stuck at 0.2.0 through three releases. The
version-drift check added in v0.3.1 only looked at VERSION= in shell scripts, so it
missed the one file that actually shows a version to users (--version). The check
now covers __version__ too -- and caught this immediately.

118 tests, ruff and shellcheck clean.

CHANGELOG.md

@@ -1,5 +1,64 @@
 # Changelog
 
+## v0.3.3 — 2026-07-13
+
+### Security
+
+- **The restic repository password no longer passes through a process's argv.**
+  `create_task.py` shelled out to `midclt call cloud_backup.create '<json>'`, and
+  that JSON contains the repo password — so it appeared in the process's argv,
+  which is world-readable via `ps`, for the duration of the call. That password is
+  the encryption key for the entire cloud backup repository.
+
+  It now talks to the middleware through `truenas_api_client` (the library that
+  backs `midclt` itself), so the password never leaves the process's memory.
+
+- **`--password` no longer required.** Passing a secret as a CLI argument writes it
+  to shell history permanently. `--password-stdin` reads it from stdin, and with
+  neither flag the tool prompts via `getpass`. `--password` still works but now
+  warns.
+
+### Fixed
+
+- **`uninstall.sh` could leave every patch installed.** It reverted by unmounting
+  the overlay — but `apply.sh` only mounts one when the target directory is
+  read-only. On a writable `/usr` it patches the real files in place, and uninstall
+  would remove the boot hook, report success, and leave the patch applied. It now
+  strips the appended blocks from the middleware files explicitly.
+
+- **`create_task.py.__version__` had been stuck at `0.2.0`** for three releases.
+  The version-drift check added in v0.3.1 only looked at `VERSION=` in shell
+  scripts, so it missed the one file that actually shows a version to users
+  (`--version`). The check now covers `__version__` too — and caught this
+  immediately.
+
+## v0.3.2 — 2026-07-13
+
+### Fixed
+
+- **`install.sh --disable-nested-snapshots` did not actually disable anything
+  until the next reboot.** `apply.sh` only ever *added* patches — there was no
+  revert path. Disabling removed the opt-in marker and then merely *skipped*
+  re-applying, but the overlay persists for the whole boot, so the previously
+  patched `plugins/cloud/{snapshot,crud}.py`, `plugins/cloud_backup/sync.py` and
+  `_truecloud_nested.py` were all still sitting there — and middlewared
+  re-imported them on the restart `install.sh` performs.
+
+  It printed *"DISABLED (stock guard restored)"* while the feature kept running.
+  Someone turning it off *because they were worried about it* would have believed
+  it was off.
+
+  `apply.sh` now actively reverts: it removes the module first (every injected
+  block is guarded by `if _tc_nested is not None`, so the stock guard is restored
+  even if a later step fails), then strips its appended blocks from the three
+  patched files. `restic.py` also carries a `TRUECLOUD_PATCH` block but belongs to
+  the *providers* module and is deliberately left alone — reverting it would break
+  B2 backups. `install.sh --disable` also tears down any staging tree first, since
+  those bind mounts pin ZFS snapshots that could otherwise never be destroyed.
+
+  Updating **without** the flag was always correct and is unchanged: the nested
+  module is never installed into middleware unless it is explicitly enabled.
+
 ## v0.3.1 — 2026-07-13
 
 ### Added

install.sh

@@ -18,7 +18,7 @@
 
 set -euo pipefail
 
-VERSION="0.3.1"
+VERSION="0.3.3"
 
 # The directory containing install.sh is the permanent install location.
 PATCH_DIR="$(cd "$(dirname "$0")" && pwd)"
@@ -160,10 +160,17 @@ case "$_nested_choice" in
     off)
         if [ -f "$_NESTED_MARKER" ]; then
             rm -f "$_NESTED_MARKER"
-            echo "Nested-dataset snapshots: DISABLED (stock guard restored)."
+            # Tear down any staging tree first: those bind mounts PIN their ZFS
+            # snapshots, so leaving them would block those snapshots from ever
+            # being destroyed. apply.sh (below) then reverts the patched files.
+            python3 "$PATCH_DIR/patch/truecloud_nested.py" cleanup || \
+                echo "  WARNING: staging mounts remain; unmount them manually."
+            echo "Nested-dataset snapshots: DISABLED."
+            echo "  apply.sh will revert the patched middleware files and the stock"
+            echo "  guard is restored when middlewared restarts (this script does that)."
             echo "  Any task that already has snapshot=true on a nested dataset will"
             echo "  fail validation on its next edit. Turn the option off on those"
-            echo "  tasks, or re-run with --enable-nested-snapshots."
+            echo "  tasks first, or re-run with --enable-nested-snapshots."
         else
             echo "Nested-dataset snapshots: already disabled."
         fi

patch/apply.sh

@@ -32,7 +32,7 @@
 # Derive PATCH_DIR from this script's location (parent of the patch/ directory).
 PATCH_DIR="$(cd "$(dirname "$0")/.." && pwd)"
 LOG="$PATCH_DIR/apply.log"
-VERSION="0.3.1"
+VERSION="0.3.3"
 
 # Rotate log at 512 KB to avoid unbounded growth on a system volume.
 # Keep two prior generations (.1 and .2) so the last three boots are always available.
@@ -477,6 +477,57 @@ def patch_file(path, block):
     with open(path, "w", encoding="utf-8") as fh:
         fh.write(base.rstrip("\n") + "\n" + block)
 
+
+def unpatch_file(path):
+    """Strip our appended block, restoring the stock file. True if it was patched."""
+    try:
+        with open(path, encoding="utf-8") as fh:
+            content = fh.read()
+    except OSError:
+        return False
+    idx = content.find("\n# TRUECLOUD_PATCH")
+    if idx == -1:
+        return False
+    try:
+        with open(path, "w", encoding="utf-8") as fh:
+            fh.write(content[:idx].rstrip("\n") + "\n")
+    except OSError:
+        return False
+    return True
+
+
+def revert_nested(cloud_dir, sync_path):
+    """Undo the nested patch. Returns the names of what was actually reverted.
+
+    Skipping the patch is NOT enough to disable the feature. The overlay persists
+    for the whole boot, so an earlier run this boot may already have written the
+    patched files -- and middlewared re-imports them on the restart that
+    install.sh performs. Without this, `install.sh --disable-nested-snapshots`
+    would report "disabled" while the feature kept running until the next reboot.
+    """
+    reverted = []
+
+    # Remove the module FIRST. Every injected block is guarded by
+    # `if _tc_nested is not None`, so once it is gone they all no-op even if a
+    # later step here fails -- the guard is restored no matter what.
+    try:
+        os.unlink(os.path.join(cloud_dir, '_truecloud_nested.py'))
+        reverted.append('_truecloud_nested.py')
+    except OSError:
+        pass
+
+    # NB: restic.py also carries a TRUECLOUD_PATCH block, but that belongs to the
+    # providers module. Only these three are ours to revert.
+    for name, path in (
+        ('crud.py', os.path.join(cloud_dir, 'crud.py')),
+        ('sync.py', sync_path),
+        ('snapshot.py', os.path.join(cloud_dir, 'snapshot.py')),
+    ):
+        if unpatch_file(path):
+            reverted.append(name)
+
+    return reverted
+
 b2_ok = restic_ok = False
 nested_ok = False
 
@@ -517,16 +568,28 @@ else:
 # guard LAST. If anything fails partway, the guard is still in place and the
 # option stays unavailable -- we never expose "guard removed, traversal missing".
 nested_detail = ''
-if not nested_enabled:
+if not nested_needed:
+    # Not just "skip": actively revert. The overlay lives for the whole boot, so a
+    # previously-applied patch is still sitting there and middlewared would
+    # re-import it on restart. See revert_nested().
+    if not nested_enabled:
         nested_detail = 'disabled (opt-in; enable with: install.sh --enable-nested-snapshots)'
         print('INFO: Nested-dataset snapshot support is disabled (opt-in feature).')
-    print('INFO: Enable with: bash install.sh --enable-nested-snapshots')
-elif nested_native:
+    elif nested_native:
         nested_detail = 'superseded: TrueNAS handles nested-dataset snapshots natively'
         print('INFO: Nested module skipped — TrueNAS now handles nesting natively.')
-elif not nested_needed:
+    else:
         nested_detail = 'not needed'
         print('INFO: Nested module skipped.')
+
+    reverted = revert_nested(cloud_dir, sync_path)
+    if reverted:
+        print('OK: Reverted a previously-applied nested patch (' + ', '.join(reverted) + ').')
+        print('    The stock nesting guard is restored once middlewared restarts.')
+        nested_detail += ' — previous patch reverted'
+
+    if not nested_enabled:
+        print('INFO: Enable with: bash install.sh --enable-nested-snapshots')
 else:
     try:
         snapshot_py = os.path.join(cloud_dir, 'snapshot.py')

patch/create_task.py

@@ -26,8 +26,9 @@ Create a task backed by a B2 credential (id=3):
         --credential 3 \\
         --bucket my-bucket \\
         --folder backups/tank \\
-        --password "restic-repo-password" \\
+        --password-stdin \\
         --keep-last 14
+    (pipe the password in:  echo -n "s3cret" | python3 create_task.py create ... )
 
 Create a task using an S3-compatible credential (Wasabi, R2, etc.):
     python3 create_task.py create \\
@@ -36,7 +37,7 @@ Create a task using an S3-compatible credential (Wasabi, R2, etc.):
         --credential 5 \\
         --bucket my-bucket \\
         --folder backups \\
-        --password "restic-repo-password"
+        --password-stdin
 
 List existing TrueCloud Backup tasks:
     python3 create_task.py list-tasks
@@ -44,39 +45,49 @@ List existing TrueCloud Backup tasks:
 
 import argparse
 import calendar
+import getpass
 import json
 import os
 import subprocess
 import sys
 import time
 
-__version__ = "0.2.0"
+__version__ = "0.3.3"
 
 _PATCH_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 _STATUS_FILE = os.path.join(_PATCH_DIR, "hook_status.json")
 
 
 def midclt_call(method, *args):
-    """Call a middleware method locally via `midclt`, the supported JSON-RPC transport
-    that replaces the deprecated /api/v2.0 REST API (removed in TrueNAS 26.04). Must run
-    on the TrueNAS host. Each arg is JSON-encoded (a dict for create; none for queries).
-    Exits with a clear message on failure."""
-    cmd = ["midclt", "call", method] + [json.dumps(a) for a in args]
+    """Call a middleware method on the local host.
+
+    Uses `truenas_api_client` -- the library that backs `midclt` itself -- rather
+    than shelling out to `midclt`.
+
+    This is a SECURITY requirement, not a style choice. `midclt call <method>
+    <json>` puts its arguments in the process's **argv**, and `cloud_backup.create`
+    carries the restic repository password. argv is world-readable via `ps`, so
+    shelling out would expose the key to the entire backup repo to every local
+    user for the duration of the call. Going through the client library keeps it
+    in this process's memory.
+    """
     try:
-        proc = subprocess.run(cmd, capture_output=True, text=True, timeout=120)
-    except FileNotFoundError:
-        print("ERROR: `midclt` not found — run this script ON the TrueNAS host.",
-              file=sys.stderr)
+        from truenas_api_client import Client
+    except ImportError:
+        print(
+            "ERROR: `truenas_api_client` not importable — run this script ON the\n"
+            "       TrueNAS host. (It ships with midclt.)",
+            file=sys.stderr,
+        )
         sys.exit(1)
-    except subprocess.SubprocessError as exc:
-        print(f"ERROR: midclt call failed: {exc}", file=sys.stderr)
+
+    try:
+        with Client() as client:
+            return client.call(method, *args)
+    except Exception as exc:  # noqa: BLE001 - surface any middleware error verbatim
+        # Never echo `args` here: for cloud_backup.create it contains the password.
+        print(f"ERROR: {method}: {exc}", file=sys.stderr)
         sys.exit(1)
-    if proc.returncode != 0:
-        print(f"ERROR: midclt {method}: {(proc.stderr or proc.stdout).strip()}",
-              file=sys.stderr)
-        sys.exit(1)
-    out = proc.stdout.strip()
-    return json.loads(out) if out else None
 
 
 # ── Sub-commands ──────────────────────────────────────────────────────────────
@@ -213,6 +224,37 @@ def cmd_list_tasks(_args):
         print(f"{t['id']:>4}  {enabled:<8}  {ptype:<14}  {t.get('description', '')}")
 
 
+def _resolve_password(args):
+    """Get the restic repo password without writing it to the user's shell history.
+
+    That password is the key to the whole backup repository. `--password <secret>`
+    persists it in ~/.bash_history and exposes it in `ps` for the lifetime of the
+    shell command, so it is accepted but warned about; stdin and an interactive
+    prompt are the safe paths.
+    """
+    if args.password_stdin:
+        if args.password:
+            print("ERROR: use either --password or --password-stdin, not both.",
+                  file=sys.stderr)
+            sys.exit(1)
+        password = sys.stdin.readline().rstrip("\n")
+    elif args.password:
+        print(
+            "WARNING: --password puts the restic repository password in your shell\n"
+            "         history. Prefer:  echo -n 'pw' | ... --password-stdin",
+            file=sys.stderr,
+        )
+        password = args.password
+    else:
+        password = getpass.getpass("Restic repository password: ")
+
+    if not password:
+        print("ERROR: the restic repository password must not be empty.",
+              file=sys.stderr)
+        sys.exit(1)
+    return password
+
+
 def cmd_create(args):
     parts = args.schedule.split()
     if len(parts) != 5:
@@ -223,6 +265,8 @@ def cmd_create(args):
         sys.exit(1)
     minute, hour, dom, month, dow = parts
 
+    password = _resolve_password(args)
+
     body = {
         "description": args.name,
         "path": args.path,
@@ -231,7 +275,7 @@ def cmd_create(args):
             "bucket": args.bucket,
             "folder": args.folder,
         },
-        "password": args.password,
+        "password": password,
         "keep_last": args.keep_last,
         "transfer_setting": args.transfer_setting,
         "schedule": {
@@ -297,8 +341,11 @@ def main():
                    help="Bucket (S3) or container (B2) name")
     c.add_argument("--folder",      default="",
                    help="Path within the bucket (default: root)")
-    c.add_argument("--password",    required=True,
-                   help="Restic repository encryption password (choose a strong one)")
+    c.add_argument("--password",    default=None,
+                   help="Restic repository password. UNSAFE: it lands in your shell "
+                        "history. Prefer --password-stdin, or omit both and be prompted.")
+    c.add_argument("--password-stdin", action="store_true",
+                   help="Read the restic repository password from stdin (recommended)")
     c.add_argument("--keep-last",   type=int, default=14, metavar="N",
                    help="Snapshots to retain after each run (default: 14)")
     c.add_argument("--schedule",    default="0 2 * * *",

recover.sh

@@ -17,7 +17,7 @@
 #   bash /mnt/tank/truenas-truecloud-patch/patch/apply.sh
 #   systemctl restart middlewared
 
-VERSION="0.3.1"
+VERSION="0.3.3"
 
 PATCH_DIR="$(cd "$(dirname "$0")" && pwd)"
 

tests/test_apply_blocks.py

@@ -263,10 +263,57 @@ class TestOptIn:
     def test_patching_is_skipped_entirely_when_disabled(self):
         # The guard-relaxing crud.py patch must be inside the enabled branch.
         src = heredoc_source()
-        gate = src.index("if not nested_enabled:")
+        gate = src.index("if not nested_needed:")
         crud = src.index("patch_file(crud_py, CRUD_BLOCK)")
         assert gate < crud, "crud.py patch must sit inside the opt-in branch"
 
+    def test_disabling_REVERTS_the_patch_rather_than_merely_skipping_it(self):
+        """Skipping is not disabling.
+
+        The overlay persists for the whole boot, so a patch applied by an earlier
+        run this boot is still on disk — and middlewared re-imports it on the
+        restart install.sh performs. Without an active revert,
+        `--disable-nested-snapshots` reports "disabled" while the feature keeps
+        running until the next reboot.
+        """
+        src = heredoc_source()
+        assert "def unpatch_file(" in src
+        assert "def revert_nested(" in src
+        # The revert must run on every not-needed path (opt-out, superseded).
+        gate = src.index("if not nested_needed:")
+        revert = src.index("reverted = revert_nested(")
+        patch = src.index("patch_file(crud_py, CRUD_BLOCK)")
+        assert gate < revert < patch, "revert belongs in the not-needed branch"
+
+    def test_revert_removes_the_module_before_unpatching_files(self):
+        # Every injected block is guarded by `if _tc_nested is not None`, so
+        # deleting the module first means the guard is restored even if a later
+        # unpatch step fails.
+        src = heredoc_source()
+        body = src[src.index("def revert_nested("):src.index("def patch_file(") if
+                   src.index("def patch_file(") > src.index("def revert_nested(") else len(src)]
+        body = src[src.index("def revert_nested("):]
+        body = body[:body.index("\n\n\n")] if "\n\n\n" in body else body
+        assert body.index("_truecloud_nested.py") < body.index("crud.py")
+
+    def test_revert_never_touches_the_providers_patch(self):
+        # restic.py also carries a TRUECLOUD_PATCH block, but it belongs to the
+        # providers module. Reverting it would silently break B2 backups.
+        src = heredoc_source()
+        body = src[src.index("def revert_nested("):]
+        body = body[:body.index("return reverted")]
+        # Comments legitimately *mention* restic.py to explain why it is excluded;
+        # what matters is that no code line touches it.
+        code = "\n".join(
+            ln for ln in body.splitlines() if not ln.lstrip().startswith("#")
+        )
+        assert "restic" not in code
+        assert "b2.py" not in code
+        # It must only ever revert these three, plus the module itself.
+        assert "crud.py" in code
+        assert "sync_path" in code
+        assert "snapshot.py" in code
+
 
 def test_guard_is_relaxed_only_after_traversal_is_installed():
     # Ordering in apply.sh is a safety property: copy module -> patch snapshot.py

tests/test_create_task.py

@@ -0,0 +1,107 @@
+"""Tests for create_task.py, focused on the restic repository password.
+
+That password is the encryption key for the entire cloud backup repository. It
+used to travel through `midclt call cloud_backup.create '<json>'` -- i.e. through
+the subprocess's **argv**, which is world-readable via `ps` -- and `--password`
+wrote it into the user's shell history forever.
+"""
+
+import importlib.util
+import io
+import os
+import sys
+import types
+
+import pytest
+
+SPEC = importlib.util.spec_from_file_location(
+    "create_task",
+    os.path.join(os.path.dirname(__file__), "..", "patch", "create_task.py"),
+)
+
+
+def load():
+    mod = importlib.util.module_from_spec(SPEC)
+    SPEC.loader.exec_module(mod)
+    return mod
+
+
+class Args:
+    def __init__(self, password=None, password_stdin=False):
+        self.password = password
+        self.password_stdin = password_stdin
+
+
+class TestPasswordNeverReachesArgv:
+    """The whole reason this module talks to the client library."""
+
+    def test_midclt_call_spawns_no_subprocess(self):
+        import inspect
+
+        src = inspect.getsource(load().midclt_call)
+        assert "subprocess" not in src, (
+            "shelling out to `midclt` puts cloud_backup.create's JSON -- including "
+            "the restic repo password -- into argv, which any local user can read "
+            "with ps"
+        )
+        assert "truenas_api_client" in src
+
+    def test_errors_never_echo_the_call_arguments(self):
+        # A failed cloud_backup.create must not print the body back at the user;
+        # it contains the password.
+        import inspect
+
+        src = inspect.getsource(load().midclt_call)
+        assert "{args}" not in src
+        assert "args!r" not in src
+
+
+class TestResolvePassword:
+    def test_reads_from_stdin(self, monkeypatch):
+        mod = load()
+        monkeypatch.setattr(sys, "stdin", io.StringIO("s3cret\n"))
+        assert mod._resolve_password(Args(password_stdin=True)) == "s3cret"
+
+    def test_strips_only_the_trailing_newline(self, monkeypatch):
+        # A password may legitimately contain spaces; only the line ending goes.
+        mod = load()
+        monkeypatch.setattr(sys, "stdin", io.StringIO("  pass word  \n"))
+        assert mod._resolve_password(Args(password_stdin=True)) == "  pass word  "
+
+    def test_cli_password_still_works_but_warns(self, monkeypatch, capsys):
+        mod = load()
+        pw = mod._resolve_password(Args(password="cli-secret"))
+        assert pw == "cli-secret"
+        assert "shell" in capsys.readouterr().err.lower(), "must warn about history"
+
+    def test_prompts_when_neither_flag_given(self, monkeypatch):
+        mod = load()
+        monkeypatch.setattr(
+            mod, "getpass", types.SimpleNamespace(getpass=lambda _p: "prompted")
+        )
+        assert mod._resolve_password(Args()) == "prompted"
+
+    def test_rejects_both_flags(self, monkeypatch):
+        mod = load()
+        monkeypatch.setattr(sys, "stdin", io.StringIO("x\n"))
+        with pytest.raises(SystemExit):
+            mod._resolve_password(Args(password="a", password_stdin=True))
+
+    def test_rejects_an_empty_password(self, monkeypatch):
+        # An empty restic password would silently create an unencrypted-ish repo.
+        mod = load()
+        monkeypatch.setattr(sys, "stdin", io.StringIO("\n"))
+        with pytest.raises(SystemExit):
+            mod._resolve_password(Args(password_stdin=True))
+
+
+class TestVersion:
+    def test_version_is_not_stale(self):
+        # __version__ sat at 0.2.0 through three releases because the drift check
+        # only looked at VERSION= in shell scripts. It covers this file now.
+        sys.path.insert(0, os.path.join(os.path.dirname(__file__), "..", "tools"))
+        from release_notes import normalise, script_versions
+
+        repo = os.path.join(os.path.dirname(__file__), "..")
+        versions = {normalise(v) for v in script_versions(repo).values()}
+        assert len(versions) == 1, f"version drift: {sorted(versions)}"

tools/release_notes.py

@@ -19,17 +19,20 @@ import sys
 ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 CHANGELOG = os.path.join(ROOT, "CHANGELOG.md")
 
-# Every script prints a version; they must all agree, and agree with the tag.
-# They drifted to three different values once (0.0.4 / 0.2.1) before anything
-# checked them.
+# Everything that announces a version must agree with everything else. They drifted
+# to three different values once (0.0.4 / 0.2.1) before anything checked them --
+# and create_task.py's __version__ then sat at 0.2.0 through three more releases,
+# because the first version of this check only looked at VERSION= in shell scripts.
 VERSIONED_FILES = [
     "install.sh",
     "uninstall.sh",
     "recover.sh",
     os.path.join("patch", "apply.sh"),
+    os.path.join("patch", "create_task.py"),   # exposes `--version` to users
 ]
 
-_VERSION_RE = re.compile(r'^VERSION="([^"]+)"', re.M)
+# `VERSION="x"` (shell) or `__version__ = "x"` (python).
+_VERSION_RE = re.compile(r'^(?:VERSION=|__version__\s*=\s*)"([^"]+)"', re.M)
 _HEADING_RE = re.compile(r"^##\s+v?(\d+\.\d+\.\d+[^\s]*)", re.M)
 
 

uninstall.sh

@@ -3,7 +3,7 @@
 
 set -euo pipefail
 
-VERSION="0.3.1"
+VERSION="0.3.3"
 
 PATCH_DIR="$(cd "$(dirname "$0")" && pwd)"
 _HOOK_COMMENT='TrueCloud provider patch (S3/B2)'
@@ -91,6 +91,63 @@ if [ "$_ov_found" -eq 0 ]; then
 fi
 echo ""
 
+# ── Revert file-level patches ─────────────────────────────────────────────────
+# Unmounting the overlay is what normally reverts everything — the lower layer is
+# the untouched /usr. But apply.sh only mounts an overlay when the directory is
+# read-only; on a writable /usr it patches the real files in place. Uninstall
+# would then remove the boot hook and report success while leaving every patch
+# applied. Strip our appended blocks explicitly.
+
+echo "Reverting any file-level patches ..."
+python3 - <<'PYEOF'
+import os
+
+try:
+    import middlewared
+except ImportError:
+    print("  middlewared not importable — nothing to revert.")
+    raise SystemExit(0)
+
+mw = os.path.dirname(os.path.abspath(middlewared.__file__))
+targets = [
+    os.path.join(mw, "rclone", "remote", "b2.py"),
+    os.path.join(mw, "plugins", "cloud_backup", "restic.py"),
+    os.path.join(mw, "plugins", "cloud_backup", "sync.py"),
+    os.path.join(mw, "plugins", "cloud", "crud.py"),
+    os.path.join(mw, "plugins", "cloud", "snapshot.py"),
+]
+
+reverted = []
+for path in targets:
+    try:
+        with open(path, encoding="utf-8") as fh:
+            content = fh.read()
+    except OSError:
+        continue
+    idx = content.find("\n# TRUECLOUD_PATCH")
+    if idx == -1:
+        continue
+    try:
+        with open(path, "w", encoding="utf-8") as fh:
+            fh.write(content[:idx].rstrip("\n") + "\n")
+        reverted.append(os.path.basename(path))
+    except OSError as e:
+        print(f"  WARNING: could not revert {path}: {e}")
+
+nested = os.path.join(mw, "plugins", "cloud", "_truecloud_nested.py")
+try:
+    os.unlink(nested)
+    reverted.append("_truecloud_nested.py")
+except OSError:
+    pass
+
+if reverted:
+    print("  Reverted: " + ", ".join(reverted))
+else:
+    print("  Nothing to revert (overlay already removed, or never patched).")
+PYEOF
+echo ""
+
 # ── Unmount nested-snapshot staging trees ─────────────────────────────────────
 # These bind mounts pin their ZFS snapshots, so they must go before anything
 # tries to destroy those snapshots. Deepest first.