3 Commits
Author SHA1 Message Date
ChuckandClaude Opus 5.5 3967a6cffc fix(security): re-harden root sudo helpers; installer fixes; ARCHITECTURE and PERMISSIONS docs (#640)
* docs: add ARCHITECTURE and PERMISSIONS guides

ARCHITECTURE.md maps the processes, the state the display and web
services share through the cache, the display loop, the plugin system,
the web UI and the update path, with links into the code and a
where-to-start table.

PERMISSIONS.md lists who owns what after install, both sudoers files
(and why iptables is not granted), the polkit rule, and which
scripts/fix_perms script to run as which user.

Both are linked from the docs index, along with the MQTT bridge README
and src/common/README.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs: correct stale setup, service and troubleshooting claims

- README: quick actions run systemctl on ledmatrix.service (run.py), not
  display_controller.py; use_short_date_format has no effect; the
  installer uses system pip with --break-system-packages, not a venv.
- CONFIG_DEBUGGING: LEDMATRIX_DEBUG must be "true"; logs are in journald.
- GETTING_STARTED, WEB_INTERFACE_GUIDE, TROUBLESHOOTING: enabling a
  plugin, plugin settings, brightness and Vegas settings apply without a
  restart; matrix hardware settings still need one.
- TROUBLESHOOTING: install dependencies with sudo so the root service
  sees them; point permission problems at PERMISSIONS.md instead of a
  project-wide chown.
- ADVANCED_FEATURES: real BackgroundDataService stats keys; Vegas hooks
  return VegasDisplayMode and None falls back to capture; cache files
  are 0660; fix_web_permissions.sh runs as the web user and does not
  touch sudoers.
- STARLARK_APPS_GUIDE: only the linux-arm64 pixlet binary is downloaded.
- HOW_TO_RUN_TESTS: test class examples that exist.
- CLAUDE.md: PluginStoreManager, plugin_dirs.py, monorepo installs via
  the Trees API with ZIP fallback, requirements.txt is optional.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs: mark deprecated plugin APIs and state manifest fields once

Methods @deprecated("3.7.0") (the set pinned in test_deprecation.py)
were shown as current API in the quick reference, API reference,
advanced guide, development guide and FONT_MANAGER. Each is now marked
deprecated with its replacement. FONT_MANAGER is rewritten around the
current API; the override editor is gone and override methods are
deprecated.

Required manifest fields were stated three different ways. The API
reference now has one section: the 7 schema-required fields, the 4 the
store refuses without, class_name for the loader, and the 8 to set.
The other guides link to it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs: document every src/common module and every widget

- src/common/README.md covered 7 of 17 modules. It now has a table of
  all of them (purpose, whether plugins import it, release to floor
  on), a short entry each, and logging advice that matches the code.
- SPORTS_UNIFICATION listed two shared modules and called
  sports_helpers the first; it now lists all six.
- The widgets README lists all 28 registered widgets plus the support
  files, and absorbs the parts that only docs/widget-guide.md had
  (x-options.labels, x-advanced, x-display hidden, plugin-file-manager).
  docs/widget-guide.md is now a pointer to it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(security): fix_web_permissions.sh re-hardens the root sudo helpers

The script chowns the whole project to the web user. That included
scripts/fix_perms/safe_plugin_rm.sh and safe_pip_install.sh -- the two
helpers /etc/sudoers.d/ledmatrix_web lets the web user run as root -- so
running it turned both into a root shell for whoever can edit them. It
also re-grouped config_secrets.json away from ledmatrix.

After the chown it now does what first_time_install.sh's Steps 11 and
11.1 do: helpers back to root:root 755, and config_secrets.json back to
the web unit's User=:ledmatrix 640. Each step is non-fatal and prints the
manual command if it fails.

Also fixes what the script and its docs claimed: it never configured
sudoers, its closing hint pointed at ./configure_web_sudo.sh (wrong
path), and the README and ADVANCED_FEATURES.md said to run it with sudo,
which it refuses.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(security): validate and harden every sudoers drop-in the scripts write

configure_wifi_permissions.sh copied its rules into
/etc/sudoers.d/ledmatrix_wifi without `visudo -c`. A malformed drop-in
makes sudo refuse every command for every user, which on a headless Pi
leaves no way back in. It now checks first and leaves the installed file
alone when the rules do not parse, as the other two writers do. (It
already used mktemp, so that part of the review did not apply.)

It also grants the two literal commands wifi_manager.py runs for
NetworkManager's shared-mode dnsmasq drop-in -- `cp
/tmp/ledmatrix-nm-dnsmasq.conf .../dnsmasq-shared.d/ledmatrix-captive.conf`
and `rm -f` of that file. The directory's mkdir was granted, the file was
not. Both are pinned in test_sudo_allowlist_covers_calls.py.

configure_web_sudo.sh wrote its rules to /tmp/ledmatrix_web_sudoers_$$,
a predictable name in a world-writable directory; it now uses mktemp with
an EXIT trap, as first_time_install.sh does. It sets mode 440 on the
installed file instead of leaving the temp file's mode, and finds visudo
in /usr/sbin when that is not on the user's PATH, which skipped the
check silently.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(install): escape the project path in the DNS-fix and MQTT unit renderers

install_dns_fix.sh and install_mqtt_bridge.sh substituted
__PROJECT_ROOT_DIR__ with the raw path, while the other three renderers
go through sed_escape_replacement from lib_systemd_render.sh. A checkout
under a path containing `&`, `\` or `|` rendered a corrupted unit from
these two only. Both now source the helper and use it, and a test checks
that every placeholder substitution in scripts/install uses an escaped
value.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(install): stop the installer scripts reporting things that are not true

- first_time_install.sh printed "Password: ledmatrix123" for the setup
  access point. wifi_manager creates it as an open network ("No
  password" on the panel), so it now says so.
- Step 10.1 printed "✓ WiFi management permissions configured" straight
  after its own failure message; install_wifi_monitor.sh printed
  "✓ Package installation completed" after a failed apt install. The
  tick now only follows success.
- Step 7 printed "Web dependencies already installed ... in Step 5" in
  the one branch that runs because Step 5 did not install them, then
  created .web_deps_installed on that basis. It now warns and leaves the
  marker off so the next run retries, as the comment below it intends.
- check_system_compatibility.sh called Debian 12 Bookworm "full
  compatibility confirmed" while first_time_install.sh refuses anything
  but Debian 13. Bookworm, older Debian and non-Debian systems are now
  errors. Its counters used ((X++)), which under `set -e` exits the
  script at the first warning or error (the expression is 0), so the
  check never reached its summary on any system with one.
- configure_web_sudo.sh and configure_wifi_permissions.sh finished by
  testing `sudo -n test -f ...` and `sudo -n nmcli device status`,
  neither of which is granted, so they always reported a failure. They
  now ask `sudo -n -l` about commands the new rules do grant, which
  checks the rule without running anything.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* fix(install): print the completion summary before rebooting

With -y -- and so for every one-shot `curl | bash` install, which always
passes -y -- first_time_install.sh ran `reboot` about 180 lines before
its "Installation Complete / Web UI Access" summary. reboot returns at
once, so the summary printed while the Pi was going down and the SSH
session usually dropped before the web UI address could be read.

The reboot block moves, unchanged, to the very end of the script. The
interactive prompt now also follows the summary. Because the summary now
runs before the -y reboot, its one command that could fail under
`set -Eeuo pipefail` (the SSID lookup, when nmcli reports a connected
device but no active network line) gets `|| true`; a missing SSID was
already handled as "SSID unknown".

one-shot-install.sh prints its "Next steps" after the installer returns,
by which time the reboot is under way, so it now says so, and README's
Quick Install mentions the automatic reboot.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* chore(scripts): correct wrong comments and messages, drop dead code

No behaviour change except the output text noted below.

- 2775 is setgid, not the sticky bit (first_time_install.sh Step 3.1,
  fix_plugin_permissions.sh), and root needs no "PWM hardware access"
  to plugin files.
- The 777 comments in first_time_install.sh Step 3's fallback and
  fix_assets_permissions.sh said root needs it to write. Root ignores
  mode bits; the comments now say what 777 actually opens. The 777
  itself is unchanged.
- apt_remove ends in `|| true`, so Step 12's "Some packages could not be
  removed" branch could never run; it is gone and the helper stays
  non-fatal.
- detect_web_service_user's comment named Step 8 for the web unit
  (install_service.sh installs it in Step 7.5) and now says which
  branch actually runs.
- Step 5 described an "already installed" check that does not exist;
  the ACTUAL_USER comment described the re-exec backwards.
- on_error printed a literal "\n" before "Common fixes:".
- Dead code: one-shot-install.sh's uncalled fix_tmp_permissions,
  LEDMATRIX_ELEVATED=1 (never read) on the sudo re-exec, and
  configure_web_sudo.sh's unused PYTHON_PATH, which also made a missing
  python3 fatal for rules that never mention it.
- start_display.sh / stop_display.sh said "for user: <you>"; the
  service runs as root.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* refactor(fix_perms): fix_cache_permissions.sh uses setup_cache.sh's model

There were two models for /var/cache/ledmatrix. setup_cache.sh (the
installer's Step 2) and install_web_service.sh share it through the
ledmatrix group: root:ledmatrix, 2775, files 660, which is also what
DiskCache relies on to give files the directory's group.
fix_cache_permissions.sh instead made it 777 and re-grouped it to the
invoking user's group, undoing that.

It now runs setup_cache.sh for /var/cache/ledmatrix and keeps its own
handling of ~/.ledmatrix_cache. Dropped: /var/cache/ledmatrix/
placeholder_logos (nothing reads it) and the checks against the
`daemon` user (no service runs as daemon).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* ci: pin actions/checkout in the Claude workflows, drop template comments

claude.yml and claude-code-review.yml used actions/checkout@v4 while
test.yml and release-version-check.yml pin the v4.2.2 commit SHA; they
now pin the same SHA. The commented-out starter-template settings
(prompt, claude_args, paths, author filter) are removed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(scripts): index every script and list removal candidates

New scripts/README.md gives one line per top-level script and scripts
directory, marked keep, dev-only or diagnostic, and lists the eight
scripts nothing in the repo refers to as candidates for removal (kept
for now). The install, utils and dev READMEs now list the files they
were missing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* test: tighten two checks that mutation testing showed were too loose

- The wifi sudoers check matched `visudo -c -f "$TEMP_SUDOERS"` in the
  error report too, so replacing the check with `if false` still passed.
  It now requires the command as the condition.
- The summary test never had the setup access point up, so reinstating
  the bogus "Password: ledmatrix123" line went unnoticed. A case with
  hostapd active now checks the AP is described as open.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(permissions): describe the repaired fix_perms scripts and new WiFi grants

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(changelog): docs-scripts

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
2026-09-24 17:31:41 -04:00
ChuckandClaude Opus 5.5 1fe7237799 refactor(install): generate the web sudoers rules in one place (#622)
* refactor(install): generate the web sudoers rules in one place

/etc/sudoers.d/ledmatrix_web was written by two copies of the same
allow-list: a heredoc in first_time_install.sh Step 10 and a block of
echo lines in scripts/install/configure_web_sudo.sh. They drifted before
(safe_pip_install.sh was granted by one only), and a test existed just
to catch that.

Both now call web_sudoers_rules() from the new
scripts/install/lib_sudoers.sh and keep their own validate (visudo -c),
install and confirm flows.

- first_time_install.sh output is byte-for-byte unchanged, so a device
  re-running the installer gets "already up to date". If the library is
  missing, Step 10 keeps the installed file and carries on, the same way
  it handles rules that fail visudo (an empty file would pass visudo).
- configure_web_sudo.sh now writes the installer's layout: same 18 rules,
  different comments and order. It still leaves out reboot, poweroff and
  journalctl when they are missing; the library does that for both.

The drift test now pins the generator's grants, checks that neither
installer writes rules of its own, and runs each installer's call line
to check the argument order. Tests that read the rule text now read the
library.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* refactor(install): detect the web service user in one function

first_time_install.sh pasted the same WEB_SERVICE_USER detection block
three times (Step 3.1's fallback, the plugin-repos setup and Step 11).
The copies were identical apart from comments; they now call
detect_web_service_user(), whose body is that block unchanged.

Behaviour is the same: the function sets the same global and always
returns 0, as the inline if-chain did. Checked on Linux against all
three original copies across 13 layouts (installed unit with and without
User=, the repo as shipped, each grep branch, template placeholders).

The comment notes that the install_web_service.sh / install_service.sh
greps no longer match anything, so until Step 8 installs the unit the
result is "root". That behaviour is left as it was.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
2026-09-24 15:51:14 -04:00
ChuckandClaude Opus 5 71739d85d1 harden: cap malloc arenas, warn on unit drift, and grant the portal's sudo commands (#476)
* perf(systemd): cap glibc malloc arenas on the display service

Measured on a live rig 2.5 hours after start:

    RSS                          1030 MB
    Private_Dirty                 988 MB
    anonymous mappings > 10 MB       23
    largest        104, 79, 66, 63, 63 MB, on 64 MB-aligned addresses
    threads                           9
    cores                             3   -> glibc ceiling = 8 x 3 = 24 arenas

23 against a ceiling of 24, all 64 MB-aligned: these are glibc's per-thread
malloc arenas, not live objects. The data the process was actually holding
accounts for perhaps 15 MB -- the widest scroll strip observed was 35,746 x 64,
about 7 MB as RGB and the same again for its numpy mirror.

It is bloat rather than a leak: sampled four times over 135 seconds, RSS sat
between 990 and 1030 MB rather than climbing. glibc gives each allocating
thread its own arena, grows them to hold peak demand, and never gives them
back. A process that builds and drops large images across several threads is
exactly the shape that produces this.

The device had 59 MB free at the time, on 1845 MB total.

MALLOC_ARENA_MAX=2 trades a little allocator concurrency for that resident
memory. It is a tuning knob rather than a fix for a defect, so the rationale
and the measurements sit next to it in the unit file, and a test asserts they
stay there -- a bare environment variable invites removal by whoever meets it
next.

Two things this is NOT, both checked rather than assumed:

- Not an OOM problem today. A grep for "oom" in the service journal returned
  24 matches, all of which were the radar logging zoom=9 and zoom=7. The kernel
  OOM killer has not fired: dmesg has zero matches.
- Not currently capped by the unit's MemoryMax=85% either. That directive is in
  this file but absent from the unit actually installed on the rig, which
  reports MemoryMax=infinity, so nothing is enforcing a ceiling there.

The saving is unmeasured on hardware: applying it needs a service restart,
which blanks the panel, so that is the user's call rather than something to do
mid-audit. If p99 frame time regresses -- it sits at 18.4 ms against a 16.7 ms
budget for 60 FPS, so there is not much headroom -- raise the value rather than
remove it.

(cherry picked from commit 446207ffbc)

* test(systemd): pin the arena value instead of accepting a range

Review follow-up. The range check accepted 1, 3 and 4, so a change to 4 --
which hands most of the resident saving back -- passed a test whose whole
purpose is to notice that.

Pinned to the value the unit ships, in one named constant. Raising it is still
a legitimate response to a frame-time regression, but it should be a visible
edit here rather than silent drift, and the failure message says so.

Mutation-checked: changing the unit to 4 now fails.
(cherry picked from commit 73fff8d2d5)

* fix(startup): warn when an installed systemd unit has drifted from the repo's

Nothing re-applies systemd units after the first install. `git pull` -- which
is what the web UI's update button runs -- brings a new template into the
checkout, but no code in web_interface/ or src/ copies it to
/etc/systemd/system, and nothing anywhere runs `systemctl daemon-reload`. The
unit that actually runs is whatever first_time_install.sh wrote on day one.

So every hardening added to a unit is inert on existing installs, silently.
Measured on a live rig:

    installed  /etc/systemd/system/ledmatrix.service   2026-08-06
    template   systemd/ledmatrix.service               2026-08-19
    contents                                           differ

with the practical result that the MemoryMax=85% the repo's template specifies
was not being enforced at all -- `systemctl show` reported
MemoryMax=infinity. Anyone reading the template would reasonably believe the
service was capped.

Startup now compares each installed unit against its substituted template and
warns when they differ, naming install_service.sh as the remedy.

A warning, not an error, and deliberately not a silent rewrite: editing files
under /etc and restarting services is the installer's job, not something a
display process should do to a machine while it is booting. Making it fatal
would also brick every development checkout whose unit is legitimately absent
or hand-edited.

Comparison ignores comments, blank lines and ordering. The template carries
explanatory comments the installed copy will not have, and systemd does not
care about order within a section, so a literal comparison would warn on every
boot and be ignored within a week.

Mutation-checked three ways: never reporting drift fails, making it fatal
fails, and -- after the first attempt missed it -- comparing raw text now fails
too. That last gap is worth noting: the comment-insensitivity tests originally
exercised the helper directly, so a comparison that stopped calling the helper
passed them all. The test that catches it goes through _validate_systemd_units.

29 startup-validator tests pass.

(cherry picked from commit cf521bdfd8)

* fix(install): grant the sudo commands the captive portal actually runs

The installers write two allow-lists, /etc/sudoers.d/ledmatrix_web and
ledmatrix_wifi. Anything the code runs under sudo that is not in one of them
needs a password, which a service cannot supply, so the call fails.

Five commands were being run and none of them granted:

    sysctl -w net.ipv4.ip_forward=0|1     wifi_manager.py:788, 883
    nft add|delete table ip ledmatrix     wifi_manager.py:835, 895
    rfkill unblock wifi                   wifi_manager.py:1811
    iptables ...                          wifi_manager.py:796, 813, 818, 871
    mkdir -p .../dnsmasq-shared.d         wifi_manager.py:922

Together these are the captive portal: unblock the radio, bring up the AP,
add the redirect, turn on forwarding, and undo all of it afterwards. Without
the grants a hardened install would associate clients to the access point and
then fail to route them.

Why it has gone unnoticed: a stock Raspberry Pi image ships
/etc/sudoers.d/010_pi-nopasswd granting the default user

    <user> ALL=(ALL) NOPASSWD: ALL

which satisfies every one of these regardless of what the allow-lists say.
Confirmed on a live rig -- `sudo -n -l` permits sysctl there, and the blanket
rule is why. The allow-lists are effectively decorative on a default image and
only start mattering once that rule is removed or the service runs as another
user.

test_sudo_allowlist_covers_calls.py extracts every argv-style sudo call in
src/ and web_interface/ and asserts an installer grants it, so the next command
added without a rule fails here rather than on someone's hardened box.

Getting that test honest took three passes, each worth recording:

- Matching the literal "systemctl" against rules written as
  `$SYSTEMCTL_PATH enable ...` reported six gaps that did not exist. Binary
  path variables are now normalised before comparing.
- Scanning the whole installer let `NFT_PATH=$(command -v nft)` -- a variable
  definition, not a grant -- satisfy the check on its own, so deleting the
  actual nft rules still passed. Only NOPASSWD lines are considered now.
- `sudo -n <tool>` reported "-n" as the binary. sudo's own flags are skipped.

Each of the five grants is individually mutation-checked: removing any one
fails the suite.

(cherry picked from commit a372b43cd1)

* fix(install): drop the iptables wildcard, and pin each grant properly

Review follow-up. Two findings, both right, and the first is a hole I opened
myself.

`NOPASSWD: iptables *` is a root shell for the web user by another name.
`iptables --modprobe=/path/to/anything` runs that path as root, so a wildcard
grant on iptables escalates rather than restricts. I added that rule while
fixing a permissions gap, which is a worse outcome than the gap. It is gone,
and a test now fails on any trailing-wildcard grant to a tool that can execute
another program -- iptables, nft, tcpdump, find, awk, sed, perl, python, env.

The other finding: checking only the binary made the coverage test far weaker
than it looked. With `sysctl` present anywhere in the allow-list, deleting the
`net.ipv4.ip_forward=0` grant still passed -- and the portal would then be
unable to restore forwarding on teardown. Each required command is now matched
in full, and each is mutation-checked individually, including that exact
single-line case.

Scope pulled in deliberately. The first version of this test tried to assert
that *every* sudo call in the codebase is granted. Run honestly, it showed the
portal also runs iptables, nft, `ip addr`, `ip link` and `cp` with arguments
built at runtime -- an interface name, a port. Those cannot be granted safely
in a sudoers file: the rule needs a trailing wildcard, and that is the
escalation above. Closing that half needs a privileged helper that builds the
rules itself and takes only an interface and a port, granted the way
safe_plugin_rm.sh already is. That is a design decision, not a one-line grant,
so the test now pins the four commands this change actually grants and the
docstring says plainly what it does not cover.

Better a narrow test that is true than a broad one that is not.

(cherry picked from commit 500cfbc9f4)

* fix(install): pin PATH, keep unit order, and tighten the sudoers assertions

Three review findings, all correct.

The installer resolved binaries through an inherited PATH and wrote whatever
it found into sudoers as NOPASSWD grants. first_time_install.sh re-execs
itself with `sudo -E`, which preserves the caller's environment, so a writable
directory early in PATH turned a compromise of the low-privilege web user into
permanent root -- via a file the installer itself wrote. PATH is now pinned to
the system directories before anything is resolved, and every resolved binary
must be root-owned and unwritable by anyone else before it reaches the
sudoers file.

_unit_body() sorted a unit's lines before comparing. Order is not noise in a
systemd unit: repeated ExecStartPre=/ExecStartPost= run in the order they
appear, and a directive that moves between [Unit], [Service] and [Install]
means something different where it lands. The drift check reported no drift
for units that had genuinely changed. Order is preserved now.

Two of that check's own tests asserted the wrong thing --
test_reordered_directives_are_not_drift said so in its name -- and are
inverted, with a second covering a directive moved between sections. The
cosmetic-difference test now varies comments, blank lines and indentation,
which is what the installer actually drops, rather than reversing the file.

The sudoers assertions matched command prefixes, so
`sysctl -w net.ipv4.ip_forward=0 *` satisfied the requirement while granting
the caller arbitrary trailing arguments as root. They are exact now. The
wildcard check also normalises ${NFT_PATH} the same way as $NFT_PATH; the
brace is not a word boundary, so that spelling was skipped entirely.

Verified by reintroducing each: a widened required grant fails the exact
match, `${NFT_PATH} *` fails the wildcard check, and require_trusted_binary
refuses a non-root-owned, world-writable, or missing binary.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01STMbQE4YctTacQXfbYqKuW

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-21 14:29:45 -04:00