Compare commits

...

2 Commits

Author SHA1 Message Date
Amir Alexander Abdelbaki 87b62f368b feat(ansipa): rework binary blocking as per-user policy; add local_sudo device policy
policy-block-binary-<name> is now a FreeIPA *user* group instead of a host group,
so restrictions follow the user to every enrolled machine. The PATH wrapper is
installed on all hosts and checks group membership at runtime via id(1)/SSSD,
passing non-members through transparently. __ in the group name decodes to .
so Flatpak app IDs are supported (flatpak run fallback included). AppArmor layer
removed since per-user confinement requires a different approach and the wrapper
alone is sufficient. Adds local_sudo_<username> host group policy which writes
a sudoers drop-in granting that user full sudo on the specific device, reverted
on group leave.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-20 16:31:43 +02:00
Amir Alexander Abdelbaki 6ad8d0d488 feat(ansipa): add no_local_users device policy to lock all local account passwords
Adds a new host group policy `no_local_users` that locks the passwords of root
and all local users (UID >= 1000) via `passwd -l`, ensuring only FreeIPA domain
accounts with centrally-managed sudo rules can authenticate and gain elevated
privileges. Leaving the group reverts by unlocking every account tracked in the
state file. Updates docs with group reference entry and Local User Lockdown section.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-05-20 16:18:48 +02:00
2 changed files with 215 additions and 98 deletions

View File

@ -265,18 +265,27 @@ Keys on the SMB share are accessible only to `KeyAdmin` group members (see [SMB
## Host Group Reference
### Device policies (host groups — applied machine-wide)
| Group prefix | Handled by | Effect |
|--------------|-----------|--------|
| `ansipa-install-<pkg>` | `ansipa-install-packages.sh` | Install/remove native package |
| `ansipa-module-<name>` | `ansipa-install-modules.sh` | Run module script once |
| `fp_install-<app>` | `ansipa-install-flatpaks.sh` | Install Flatpak app |
| `BaseUser` | `auto-add-baseuser.sh` | Add user to local `baseusers` group |
| `policy-block-binary-<name>` | `ansipa-enforce-policies.sh` | Block binary via PATH wrapper + AppArmor |
| `policy-daemon-enable-<unit>` | `ansipa-enforce-policies.sh` | `systemctl enable --now <unit>`; reverted on leave |
| `policy-daemon-disable-<unit>` | `ansipa-enforce-policies.sh` | `systemctl disable --now <unit>`; reverted on leave |
| `policy-timeshift-backup` | `ansipa-enforce-policies.sh` | Daily Timeshift snapshot at 03:00 |
| `policy-security-scan` | `ansipa-enforce-policies.sh` | Daily ClamAV + rkhunter + chkrootkit scan + SMB upload |
| `policy-scan-notify` | `ansipa-enforce-policies.sh` | Fetch server alerts, notify user every 10 min until acknowledged |
| `no_local_users` | `ansipa-enforce-policies.sh` | Lock passwords for root and all local users (UID ≥ 1000); reverted on leave |
| `local_sudo_<username>` | `ansipa-enforce-policies.sh` | Grant `<username>` full sudo on this specific device; reverted on leave |
### User policies (user groups — follow the user across all enrolled devices)
| Group prefix | Handled by | Effect |
|--------------|-----------|--------|
| `policy-block-binary-<name>` | `ansipa-enforce-policies.sh` | Prevent group members from running `<name>` on any enrolled host; use `__` for `.` in Flatpak app IDs |
---
@ -284,14 +293,17 @@ Keys on the SMB share are accessible only to `KeyAdmin` group members (see [SMB
`ansipa-enforce-policies.sh` runs every 30 minutes on each enrolled client (deployed by `deploy-ansipa-policies.yml`). All policies are idempotent and reversible — leaving a host group undoes the policy on the next run.
### Binary Blocking
### Binary Blocking (per user)
Adding a host to `policy-block-binary-<name>` applies two layers:
`policy-block-binary-<name>` is a FreeIPA **user group**, not a host group. Membership follows the user to every enrolled machine: a blocked user cannot run `<name>` regardless of which device they log into.
1. **PATH wrapper** — a script in `/usr/local/bin/<name>` that prints a policy message and exits 1. Takes priority over the real binary for `$PATH`-based calls.
2. **AppArmor deny profile**`/etc/apparmor.d/ansipa-block-<name>` with an empty profile, denying all file access. Blocks absolute-path calls and direct `exec()`. Skipped silently if `apparmor_parser` is not present.
The enforcer queries all `policy-block-binary-*` user groups from FreeIPA on every run and installs a **PATH-priority wrapper** in `/usr/local/bin/<name>` for each one. The wrapper checks the caller's group membership at runtime via `id(1)` / SSSD and:
- **blocks** the command if the caller is a group member (exits 1 with a policy message);
- **passes through** to the real binary for all other users (searches native PATH dirs, then falls back to `flatpak run <name>`).
Leaving the group removes both layers on the next enforcer run.
**Flatpak support:** use `__` in place of `.` in the group name. For example, `policy-block-binary-org__gimp__Gimp` blocks the Flatpak `org.gimp.Gimp` for group members while transparently invoking `flatpak run org.gimp.Gimp` for everyone else.
Deleting the IPA user group causes the wrapper to be removed on the next enforcer run. State is tracked in `/var/lib/ansipa-policies/blocked-binaries`.
### Daemon Enable / Disable
@ -329,6 +341,30 @@ Client (policy-scan-notify, every 10 min via systemd timer)
- `samba-client` is installed automatically by `deploy-ansipa-policies.yml`.
- SMB credentials are written to `/etc/ansipa-smb.creds` (root-only, `0600`).
### Local User Lockdown
Adding a host to the `no_local_users` group locks the password of every local account — root (UID 0) and all regular users (UID ≥ 1000) — using `passwd -l`. Accounts whose passwords are already locked (`!` or `*` prefix in shadow) are left untouched and are not tracked.
State is persisted in `/var/lib/ansipa-policies/no-local-users` (one username per line). Only accounts that were actively unlocked at apply time are written to this file, so the revert step only unlocks what was changed.
| Action | Effect |
|--------|--------|
| Join `no_local_users` | `passwd -l` on root + all UID ≥ 1000 local accounts |
| Leave `no_local_users` | `passwd -u` on every account listed in the state file |
**Interaction with FreeIPA sudo:** Domain accounts in the `sudoers` or `sudo-nopasswd` FreeIPA groups retain full sudo access via SSSD — local password lockdown does not affect them. Ensure at least one domain admin has sudo before adding a host to this group.
### Per-device sudo grants
`local_sudo_<username>` is a **host group** that grants a specific user full sudo on that particular machine, independently of FreeIPA-wide sudo rules. This is useful for giving a user admin rights on their own workstation while keeping them unprivileged on shared servers.
| Action | Effect |
|--------|--------|
| Join `local_sudo_alice` | Creates `/etc/sudoers.d/ansipa-local-sudo-alice` with `alice ALL=(ALL) ALL` |
| Leave `local_sudo_alice` | Removes the drop-in on the next enforcer run |
State is tracked in `/var/lib/ansipa-policies/local-sudo-users`. Drop-ins are mode `0440` and validated by `visudo` syntax rules automatically.
---
## LUKS Key Flow

View File

@ -4,11 +4,7 @@
# Policies are idempotent and reversible: joining a group applies the policy;
# leaving the group removes it on the next run (every 30 min via systemd timer).
#
# Host-group naming conventions:
# policy-block-binary-<name> Block execution of <name> via two layers:
# 1. PATH-priority wrapper in /usr/local/bin/ (catches $PATH calls)
# 2. AppArmor deny profile in /etc/apparmor.d/ (catches absolute paths)
# AppArmor layer is skipped silently if apparmor_parser is not present.
# Host-group naming conventions (device policies — applied to the whole machine):
# policy-daemon-enable-<unit> Ensure <unit> is enabled and running (systemctl enable --now).
# Leaving the group reverts: service is disabled and stopped.
# policy-daemon-disable-<unit> Ensure <unit> is disabled and stopped (systemctl disable --now).
@ -17,6 +13,22 @@
# If a unit appears in both enable and disable groups it is skipped.
# policy-timeshift-backup Enforce a daily Timeshift snapshot (requires timeshift installed)
# policy-security-scan Enforce daily ClamAV + rkhunter + chkrootkit scans
# no_local_users Lock passwords for root and all local users (UID >= 1000) so
# that only FreeIPA domain accounts with centrally-managed sudo
# rules can authenticate and gain elevated privileges.
# Leaving the group reverts: every account locked by this policy
# is unlocked on the next run.
# local_sudo_<username> Grant <username> full sudo on this specific device by adding
# them to the local sudoers drop-in. Leaving the group removes
# the drop-in on the next run.
#
# User-group naming conventions (per-user policies — follow the user across devices):
# policy-block-binary-<name> Prevent members of this FreeIPA user group from running <name>
# on any enrolled host. Use __ in place of . to support Flatpak
# app IDs (e.g. policy-block-binary-org__gimp__Gimp blocks the
# Flatpak org.gimp.Gimp). Enforced via a PATH-priority wrapper
# that checks group membership at runtime via SSSD/id(1).
# Removing the user group from FreeIPA reverts the wrapper.
#
# Notes:
# - Install scan tools first: add the host to ansipa-module-anti-malware.
@ -27,7 +39,6 @@ set -euo pipefail
LOG_TAG="ansipa-policies"
STATE_DIR="/var/lib/ansipa-policies"
BLOCK_DIR="/usr/local/bin"
APPARMOR_DIR="/etc/apparmor.d"
CRON_DIR="/etc/cron.d"
log() { echo "[$LOG_TAG] $*"; logger -t "$LOG_TAG" "$*" 2>/dev/null || true; }
@ -47,37 +58,59 @@ mkdir -p "$STATE_DIR"
RAW_GROUPS=$(ipa host-show "$HOST_FQDN" --all 2>/dev/null \
| grep -i "Member of host-groups:" | sed 's/.*: //' || true)
# ── Parse active policy groups ────────────────────────────────────────────────
ACTIVE_BLOCK_BINARIES=()
# ── Parse active host-group (device) policies ─────────────────────────────────
ACTIVE_DAEMON_ENABLE=()
ACTIVE_DAEMON_DISABLE=()
ACTIVE_LOCAL_SUDO_USERS=()
WANT_TIMESHIFT_BACKUP=false
WANT_SECURITY_SCAN=false
WANT_SCAN_NOTIFY=false
WANT_NO_LOCAL_USERS=false
if [[ -n "$RAW_GROUPS" ]]; then
while IFS=',' read -ra GRP_ARRAY; do
for g in "${GRP_ARRAY[@]}"; do
g="${g// /}"
case "$g" in
policy-block-binary-*) ACTIVE_BLOCK_BINARIES+=("${g#policy-block-binary-}") ;;
policy-daemon-enable-*) ACTIVE_DAEMON_ENABLE+=("${g#policy-daemon-enable-}") ;;
policy-daemon-disable-*) ACTIVE_DAEMON_DISABLE+=("${g#policy-daemon-disable-}") ;;
policy-timeshift-backup) WANT_TIMESHIFT_BACKUP=true ;;
policy-security-scan) WANT_SECURITY_SCAN=true ;;
policy-scan-notify) WANT_SCAN_NOTIFY=true ;;
no_local_users) WANT_NO_LOCAL_USERS=true ;;
local_sudo_*) ACTIVE_LOCAL_SUDO_USERS+=("${g#local_sudo_}") ;;
esac
done
done <<< "$RAW_GROUPS"
fi
log "Active policies — block-binary: ${ACTIVE_BLOCK_BINARIES[*]:-none}" \
"| daemon-enable: ${ACTIVE_DAEMON_ENABLE[*]:-none} | daemon-disable: ${ACTIVE_DAEMON_DISABLE[*]:-none}" \
"| timeshift-backup: $WANT_TIMESHIFT_BACKUP" \
"| security-scan: $WANT_SECURITY_SCAN | scan-notify: $WANT_SCAN_NOTIFY"
# ── Fetch user-group-based binary block policies from FreeIPA ─────────────────
# policy-block-binary-<name> groups are FreeIPA *user* groups — membership follows
# the user to every enrolled host rather than being tied to a device.
ACTIVE_BLOCK_BINARIES=()
ACTIVE_BLOCK_IPA_GROUPS=()
_BLOCK_LIST=$(ipa group-find --pkey-only 2>/dev/null \
| awk '/Group name:/ {print $NF}' \
| grep "^policy-block-binary-" | sort -u || true)
while IFS= read -r _grp; do
[[ -z "$_grp" ]] && continue
_raw="${_grp#policy-block-binary-}"
ACTIVE_BLOCK_BINARIES+=("${_raw//__/.}")
ACTIVE_BLOCK_IPA_GROUPS+=("$_grp")
done <<< "$_BLOCK_LIST"
unset _BLOCK_LIST _grp _raw
log "Device policies — daemon-enable: ${ACTIVE_DAEMON_ENABLE[*]:-none}" \
"| daemon-disable: ${ACTIVE_DAEMON_DISABLE[*]:-none}" \
"| timeshift-backup: $WANT_TIMESHIFT_BACKUP | security-scan: $WANT_SECURITY_SCAN" \
"| scan-notify: $WANT_SCAN_NOTIFY | no-local-users: $WANT_NO_LOCAL_USERS" \
"| local-sudo: ${ACTIVE_LOCAL_SUDO_USERS[*]:-none}"
log "User policies — block-binary: ${ACTIVE_BLOCK_BINARIES[*]:-none}"
# ── Helpers ───────────────────────────────────────────────────────────────────
in_active_list() {
_in_block_list() {
local needle="$1"
for b in "${ACTIVE_BLOCK_BINARIES[@]}"; do
[[ "$b" == "$needle" ]] && return 0
@ -85,102 +118,53 @@ in_active_list() {
return 1
}
# Find the real installed binary, skipping /usr/local/bin where our wrapper lives.
find_real_binary() {
local name="$1"
for dir in /usr/bin /usr/sbin /bin /sbin /usr/local/sbin /opt/bin; do
[[ -x "$dir/$name" ]] && echo "$dir/$name" && return 0
done
return 1
}
aa_profile_file() { echo "$APPARMOR_DIR/ansipa-block-${1}"; }
# Load an AppArmor deny profile for a binary path.
# An empty AppArmor profile denies all access: the binary cannot load shared
# libraries or open any files, so it exits immediately with a permission error.
apply_apparmor_block() {
local bin="$1"
command -v apparmor_parser &>/dev/null || return 0
local bin_path
bin_path=$(find_real_binary "$bin") || {
warn "AppArmor block: real binary '$bin' not found on disk — profile skipped until it is installed."
return 0
}
local profile_file
profile_file=$(aa_profile_file "$bin")
# Write the profile only if it doesn't exist or points to a different path.
if [[ ! -f "$profile_file" ]] || ! grep -qF "$bin_path" "$profile_file" 2>/dev/null; then
log "Writing AppArmor block profile: $profile_file ($bin_path)"
cat > "$profile_file" <<PROFILE
#include <tunables/global>
# ansipa-block-policy: managed by ansipa-enforce-policies — do not edit manually.
# Deny all access so the binary cannot load libraries or run.
# To unblock manually: apparmor_parser -R $profile_file && rm $profile_file
$bin_path {
}
PROFILE
fi
# Load (or reload) the profile in enforce mode.
if ! apparmor_parser -r "$profile_file" 2>/dev/null; then
warn "apparmor_parser failed to load $profile_file — AppArmor block not active"
fi
}
# Remove the AppArmor deny profile for a binary.
remove_apparmor_block() {
local bin="$1"
command -v apparmor_parser &>/dev/null || return 0
local profile_file
profile_file=$(aa_profile_file "$bin")
[[ -f "$profile_file" ]] || return 0
if grep -q "ansipa-block-policy" "$profile_file" 2>/dev/null; then
apparmor_parser -R "$profile_file" 2>/dev/null || true
rm -f "$profile_file"
log "Removed AppArmor block profile: $bin"
fi
}
# ── Binary blocking ───────────────────────────────────────────────────────────
# Layer 1: PATH-priority wrapper in /usr/local/bin/ — blocks $PATH-based calls.
# Layer 2: AppArmor deny profile — blocks absolute-path calls and direct exec().
# Both layers use the "ansipa policy" sentinel to identify managed files.
# ── Binary blocking (user-based) ──────────────────────────────────────────────
# A PATH-priority wrapper is installed in /usr/local/bin/ for every binary named
# by a policy-block-binary-* FreeIPA *user* group. The wrapper checks the
# caller's group membership at runtime (via id + SSSD) and only blocks members;
# non-members are transparently passed through to the real binary.
# __ in the group suffix decodes to . so Flatpak app IDs are fully supported.
# Removing the IPA user group causes the wrapper to be cleaned up on the next run.
BLOCK_STATE="$STATE_DIR/blocked-binaries"
[[ -f "$BLOCK_STATE" ]] || touch "$BLOCK_STATE"
for BIN in "${ACTIVE_BLOCK_BINARIES[@]}"; do
for _idx in "${!ACTIVE_BLOCK_BINARIES[@]}"; do
BIN="${ACTIVE_BLOCK_BINARIES[$_idx]}"
IPA_GRP="${ACTIVE_BLOCK_IPA_GROUPS[$_idx]}"
WRAPPER="$BLOCK_DIR/$BIN"
if [[ ! -f "$WRAPPER" ]] || ! grep -q "blocked by ansipa policy" "$WRAPPER" 2>/dev/null; then
log "Applying PATH wrapper block: $BIN"
# Write (or refresh) the wrapper when it is absent, not ours, or the group name changed.
if [[ ! -f "$WRAPPER" ]] \
|| ! grep -q "blocked by ansipa policy" "$WRAPPER" 2>/dev/null \
|| ! grep -qF "$IPA_GRP" "$WRAPPER" 2>/dev/null; then
log "Installing user-aware block wrapper: $BIN (group: $IPA_GRP)"
cat > "$WRAPPER" <<WRAPPER
#!/bin/bash
# blocked by ansipa policy
echo "[$LOG_TAG] '$BIN' is blocked by system policy on this host." >&2
exit 1
# blocked by ansipa policy (user-based)
if id -Gn 2>/dev/null | tr ' ' '\n' | grep -qxF "${IPA_GRP}"; then
echo "[ansipa-policies] '${BIN}' is blocked by system policy for your account." >&2
exit 1
fi
_real=\$(PATH="/usr/bin:/usr/sbin:/bin:/sbin:/usr/local/sbin:/opt/bin:/var/lib/flatpak/exports/bin:/usr/share/flatpak/exports/bin" command -v "${BIN}" 2>/dev/null)
[[ -n "\$_real" ]] && exec "\$_real" "\$@"
command -v flatpak &>/dev/null && exec flatpak run "${BIN}" "\$@" 2>/dev/null
echo "${BIN}: command not found" >&2
exit 127
WRAPPER
chmod 755 "$WRAPPER"
fi
apply_apparmor_block "$BIN"
done
unset _idx
# Remove blocks for binaries no longer in any active policy group.
# Remove wrappers whose IPA user group no longer exists.
while IFS= read -r OLD_BIN; do
[[ -z "$OLD_BIN" ]] && continue
if ! in_active_list "$OLD_BIN"; then
if ! _in_block_list "$OLD_BIN"; then
WRAPPER="$BLOCK_DIR/$OLD_BIN"
if [[ -f "$WRAPPER" ]] && grep -q "blocked by ansipa policy" "$WRAPPER" 2>/dev/null; then
rm -f "$WRAPPER"
log "Removed PATH wrapper block: $OLD_BIN"
log "Removed binary block wrapper: $OLD_BIN"
fi
remove_apparmor_block "$OLD_BIN"
fi
done < "$BLOCK_STATE"
@ -444,4 +428,101 @@ else
> "$DAEMON_DISABLE_STATE"
fi
# ── Per-device local sudo grants ──────────────────────────────────────────────
# local_sudo_<username>: write a sudoers drop-in granting <username> full sudo on
# this specific device. The drop-in is removed when the host leaves the group.
LOCAL_SUDO_DIR="/etc/sudoers.d"
LOCAL_SUDO_STATE="$STATE_DIR/local-sudo-users"
[[ -f "$LOCAL_SUDO_STATE" ]] || touch "$LOCAL_SUDO_STATE"
for _USER in "${ACTIVE_LOCAL_SUDO_USERS[@]}"; do
_DROPIN="$LOCAL_SUDO_DIR/ansipa-local-sudo-${_USER}"
if [[ ! -f "$_DROPIN" ]]; then
log "Granting local sudo to $_USER on this device"
echo "$_USER ALL=(ALL) ALL" > "$_DROPIN"
chmod 440 "$_DROPIN"
fi
grep -qxF "$_USER" "$LOCAL_SUDO_STATE" 2>/dev/null || echo "$_USER" >> "$LOCAL_SUDO_STATE"
done
# Revoke sudo for users no longer in any active local_sudo_* group.
while IFS= read -r _OLD_USER; do
[[ -z "$_OLD_USER" ]] && continue
_still_active=false
for _U in "${ACTIVE_LOCAL_SUDO_USERS[@]}"; do
[[ "$_U" == "$_OLD_USER" ]] && _still_active=true && break
done
if [[ "$_still_active" == false ]]; then
_DROPIN="$LOCAL_SUDO_DIR/ansipa-local-sudo-${_OLD_USER}"
if [[ -f "$_DROPIN" ]]; then
rm -f "$_DROPIN"
log "Revoked local sudo for $_OLD_USER (host left local_sudo_$_OLD_USER group)"
fi
fi
done < "$LOCAL_SUDO_STATE"
# Persist current local sudo users.
if [[ ${#ACTIVE_LOCAL_SUDO_USERS[@]} -gt 0 ]]; then
printf '%s\n' "${ACTIVE_LOCAL_SUDO_USERS[@]}" | sort -u > "$LOCAL_SUDO_STATE"
else
> "$LOCAL_SUDO_STATE"
fi
unset _USER _DROPIN _OLD_USER _still_active _U
# ── No-local-users policy ──────────────────────────────────────────────────────
# no_local_users: lock the passwords of root and all local users (UID >= 1000)
# so that only FreeIPA domain accounts with centrally-managed sudo rules can
# authenticate and gain elevated privileges.
# Leaving the group reverts: every account locked by this policy is unlocked.
NO_LOCAL_USERS_STATE="$STATE_DIR/no-local-users"
_apply_no_local_users() {
log "Applying no_local_users policy — locking local account passwords"
[[ -f "$NO_LOCAL_USERS_STATE" ]] || touch "$NO_LOCAL_USERS_STATE"
while IFS=: read -r uname _ uid _; do
[[ "$uid" =~ ^[0-9]+$ ]] || continue
{ [[ "$uid" == "0" ]] || [[ "$uid" -ge 1000 ]]; } || continue
# Skip accounts already tracked (locked on a previous run)
grep -qxF "$uname" "$NO_LOCAL_USERS_STATE" 2>/dev/null && continue
# Lock only accounts that currently have a real (unlocked) password hash
local hash
hash=$(getent shadow "$uname" 2>/dev/null | cut -d: -f2 || true)
[[ -z "$hash" || "$hash" == '!'* || "$hash" == '*'* ]] && continue
if passwd -l "$uname" &>/dev/null; then
echo "$uname" >> "$NO_LOCAL_USERS_STATE"
log "Locked local account: $uname"
else
warn "Failed to lock local account: $uname"
fi
done < /etc/passwd
}
_revert_no_local_users() {
[[ -f "$NO_LOCAL_USERS_STATE" ]] || return 0
log "Reverting no_local_users policy — unlocking previously locked accounts"
while IFS= read -r uname; do
[[ -z "$uname" ]] && continue
if passwd -u "$uname" &>/dev/null; then
log "Unlocked local account: $uname"
else
warn "Failed to unlock local account: $uname (may have been removed)"
fi
done < "$NO_LOCAL_USERS_STATE"
> "$NO_LOCAL_USERS_STATE"
}
if [[ "$WANT_NO_LOCAL_USERS" == true ]]; then
_apply_no_local_users
else
if [[ -f "$NO_LOCAL_USERS_STATE" ]] && [[ -s "$NO_LOCAL_USERS_STATE" ]]; then
_revert_no_local_users
fi
fi
log "Policy enforcement complete."