#!/usr/bin/env bash
# ansipa-enforce-policies.sh — enforce FreeIPA host-group-driven policies on this client.
#
# 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.
#   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).
#                                 Leaving the group reverts: service is re-enabled and started.
#                                 <unit> may omit the .service suffix; all systemd unit types work.
#                                 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
#
# Notes:
#   - Install scan tools first: add the host to ansipa-module-anti-malware.
#   - Configure Timeshift (type + target device) before enabling policy-timeshift-backup.

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" "$*" 2>/dev/null || true; }
warn() { echo "[$LOG_TAG][WARN] $*" >&2; logger -t "$LOG_TAG" "WARN: $*" 2>/dev/null || true; }

HOST_FQDN=$(hostname -f 2>/dev/null || hostname)

if ! command -v ipa &>/dev/null; then
    warn "ipa command not found — host not enrolled in FreeIPA. Exiting."
    exit 0
fi

kinit -k "host/$HOST_FQDN" &>/dev/null || true
mkdir -p "$STATE_DIR"

# ── Fetch host group membership ───────────────────────────────────────────────
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=()
ACTIVE_DAEMON_ENABLE=()
ACTIVE_DAEMON_DISABLE=()
WANT_TIMESHIFT_BACKUP=false
WANT_SECURITY_SCAN=false
WANT_SCAN_NOTIFY=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+=("${g#policy-daemon-disable-}") ;;
                policy-timeshift-backup) WANT_TIMESHIFT_BACKUP=true ;;
                policy-security-scan)    WANT_SECURITY_SCAN=true ;;
                policy-scan-notify)      WANT_SCAN_NOTIFY=true ;;
            esac
        done
    done <<< "$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"

# ── Helpers ───────────────────────────────────────────────────────────────────
in_active_list() {
    local needle="$1"
    for b in "${ACTIVE_BLOCK_BINARIES[@]}"; do
        [[ "$b" == "$needle" ]] && return 0
    done
    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.

BLOCK_STATE="$STATE_DIR/blocked-binaries"
[[ -f "$BLOCK_STATE" ]] || touch "$BLOCK_STATE"

for BIN in "${ACTIVE_BLOCK_BINARIES[@]}"; do
    WRAPPER="$BLOCK_DIR/$BIN"
    if [[ ! -f "$WRAPPER" ]] || ! grep -q "blocked by ansipa policy" "$WRAPPER" 2>/dev/null; then
        log "Applying PATH wrapper block: $BIN"
        cat > "$WRAPPER" <<WRAPPER
#!/bin/bash
# blocked by ansipa policy
echo "[$LOG_TAG] '$BIN' is blocked by system policy on this host." >&2
exit 1
WRAPPER
        chmod 755 "$WRAPPER"
    fi
    apply_apparmor_block "$BIN"
done

# Remove blocks for binaries no longer in any active policy group.
while IFS= read -r OLD_BIN; do
    [[ -z "$OLD_BIN" ]] && continue
    if ! in_active_list "$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: $OLD_BIN"
        fi
        remove_apparmor_block "$OLD_BIN"
    fi
done < "$BLOCK_STATE"

# Persist current blocked list.
if [[ ${#ACTIVE_BLOCK_BINARIES[@]} -gt 0 ]]; then
    printf '%s\n' "${ACTIVE_BLOCK_BINARIES[@]}" | sort -u > "$BLOCK_STATE"
else
    > "$BLOCK_STATE"
fi

# ── Timeshift daily backup ─────────────────────────────────────────────────────
TIMESHIFT_CRON="$CRON_DIR/ansipa-timeshift-backup"

if [[ "$WANT_TIMESHIFT_BACKUP" == true ]]; then
    if [[ ! -f "$TIMESHIFT_CRON" ]]; then
        if ! command -v timeshift &>/dev/null; then
            warn "timeshift not found — add host to ansipa-module-timeshift first. Cron will be installed anyway."
        fi
        log "Enabling daily Timeshift backups"
        cat > "$TIMESHIFT_CRON" <<'CRON'
# ansipa-policy-timeshift-backup: managed by ansipa-enforce-policies — do not edit manually.
# Timeshift must be configured on this host (type + target device) before snapshots work.
0 3 * * * root /usr/bin/timeshift --create --comments "ansipa-daily" --tags D 2>&1 | logger -t timeshift-backup
CRON
        chmod 644 "$TIMESHIFT_CRON"
    fi
else
    if [[ -f "$TIMESHIFT_CRON" ]]; then
        rm -f "$TIMESHIFT_CRON"
        log "Removed Timeshift backup cron (host left policy-timeshift-backup group)"
    fi
fi

# ── Security scan ─────────────────────────────────────────────────────────────
SCAN_CRON="$CRON_DIR/ansipa-security-scan"
SCAN_SCRIPT="/usr/local/bin/ansipa-security-scan.sh"

if [[ "$WANT_SECURITY_SCAN" == true ]]; then
    # (Re-)write the scan script so it stays current with this version of the enforcer.
    cat > "$SCAN_SCRIPT" <<'SCAN'
#!/bin/bash
# ansipa-security-scan — daily ClamAV / rkhunter / chkrootkit run + SMB upload.
# Managed by ansipa-enforce-policies — do not edit manually.
LOG=/var/log/ansipa-security-scan.log
HOSTNAME=$(hostname -f 2>/dev/null || hostname)
DATE=$(date +%Y-%m-%d)
{
    echo "=== ansipa-security-scan: $DATE $HOSTNAME ==="

    if command -v freshclam &>/dev/null; then
        freshclam --quiet 2>/dev/null || true
    fi
    if command -v clamscan &>/dev/null; then
        clamscan -r --infected --quiet /home /etc /tmp /var/tmp 2>/dev/null || true
    fi
    if command -v rkhunter &>/dev/null; then
        rkhunter --update --quiet 2>/dev/null || true
        rkhunter --check --skip-keypress --quiet 2>/dev/null || true
    fi
    if command -v chkrootkit &>/dev/null; then
        chkrootkit 2>/dev/null || true
    fi

    echo "=== scan complete ==="
} >> "$LOG" 2>&1

# ── Upload to server SMB share ────────────────────────────────────────────────
IPA_SERVER=$(awk '/^server[[:space:]]*=/{print $3}' /etc/ipa/default.conf 2>/dev/null || echo "")
if [[ -n "$IPA_SERVER" ]] && [[ -f /etc/ansipa-smb.creds ]] && command -v smbclient &>/dev/null; then
    # Create host archive dir (mkdir is idempotent; errors suppressed).
    smbclient "//$IPA_SERVER/ansipa-scans" -A /etc/ansipa-smb.creds \
        -c "mkdir archive; mkdir archive\\$HOSTNAME; put $LOG archive\\$HOSTNAME\\$DATE.log" \
        >> "$LOG" 2>&1 \
        && echo "[ansipa] Scan results uploaded to $IPA_SERVER/ansipa-scans/archive/$HOSTNAME/$DATE.log" >> "$LOG" \
        || echo "[ansipa][WARN] SMB upload failed — results remain local at $LOG" >> "$LOG"
else
    echo "[ansipa] SMB upload skipped (no credentials or smbclient not found)." >> "$LOG"
fi
SCAN
    chmod 755 "$SCAN_SCRIPT"

    if [[ ! -f "$SCAN_CRON" ]]; then
        log "Enabling daily security scans (ClamAV / rkhunter / chkrootkit)"
        cat > "$SCAN_CRON" <<'CRON'
# ansipa-policy-security-scan: managed by ansipa-enforce-policies — do not edit manually.
# Install scan tools by adding the host to the ansipa-module-anti-malware group.
0 2 * * * root /usr/local/bin/ansipa-security-scan.sh
CRON
        chmod 644 "$SCAN_CRON"
    fi
else
    if [[ -f "$SCAN_CRON" ]]; then
        rm -f "$SCAN_CRON"
        rm -f "$SCAN_SCRIPT"
        log "Removed security scan policy (host left policy-security-scan group)"
    fi
fi

# ── Scan notification daemon ──────────────────────────────────────────────────
# policy-scan-notify:
#   - Root timer (every 10 min): ansipa-fetch-alerts.sh downloads alerts from the
#     server SMB share and places them in ~/administration/<hostname>/ per active user.
#   - profile.d snippet: starts ansipa-scan-notify.sh as a user daemon on login;
#     the daemon sends notify-send every 10 min while *.alert files remain.
#     Deleting a file from ~/administration/ counts as acknowledgment.
#
# Requires: ansipa-fetch-alerts.sh and ansipa-scan-notify.sh deployed by
# deploy-ansipa-policies.yml (static scripts — not written inline here).

FETCH_SVC="/etc/systemd/system/ansipa-fetch-alerts.service"
FETCH_TIMER="/etc/systemd/system/ansipa-fetch-alerts.timer"
NOTIFY_PROFILED="/etc/profile.d/ansipa-notify.sh"

if [[ "$WANT_SCAN_NOTIFY" == true ]]; then
    if [[ ! -x /usr/local/bin/ansipa-fetch-alerts.sh ]]; then
        warn "ansipa-fetch-alerts.sh not found — run deploy-ansipa-policies.yml first."
    fi

    if [[ ! -f "$FETCH_SVC" ]]; then
        log "Installing ansipa-fetch-alerts systemd service + timer"
        cat > "$FETCH_SVC" <<'UNIT'
[Unit]
Description=Fetch Ansipa security alerts from the server SMB share
After=network-online.target sssd.service
Wants=network-online.target

[Service]
Type=oneshot
ExecStart=/usr/local/bin/ansipa-fetch-alerts.sh
StandardOutput=journal
StandardError=journal
UNIT

        cat > "$FETCH_TIMER" <<'UNIT'
[Unit]
Description=Periodic ansipa security alert fetch

[Timer]
OnBootSec=2min
OnUnitActiveSec=10min

[Install]
WantedBy=timers.target
UNIT
        systemctl daemon-reload
        systemctl enable --now ansipa-fetch-alerts.timer
        log "ansipa-fetch-alerts.timer enabled"
    fi

    if [[ ! -f "$NOTIFY_PROFILED" ]]; then
        log "Installing /etc/profile.d/ansipa-notify.sh"
        cat > "$NOTIFY_PROFILED" <<'PROFILED'
# ansipa-notify: launch the scan alert notification daemon on login.
# Managed by ansipa-enforce-policies — do not edit manually.
_NOTIFY_DAEMON=/usr/local/bin/ansipa-scan-notify.sh
if [[ -x "$_NOTIFY_DAEMON" ]] && \
   ! pgrep -u "$(id -u)" -f "ansipa-scan-notify" >/dev/null 2>&1; then
    "$_NOTIFY_DAEMON" &
    disown
fi
unset _NOTIFY_DAEMON
PROFILED
        chmod 644 "$NOTIFY_PROFILED"
    fi
else
    if [[ -f "$FETCH_TIMER" ]]; then
        systemctl disable --now ansipa-fetch-alerts.timer 2>/dev/null || true
        rm -f "$FETCH_SVC" "$FETCH_TIMER"
        systemctl daemon-reload
        log "Removed ansipa-fetch-alerts timer (host left policy-scan-notify group)"
    fi
    if [[ -f "$NOTIFY_PROFILED" ]]; then
        rm -f "$NOTIFY_PROFILED"
        log "Removed /etc/profile.d/ansipa-notify.sh"
    fi
fi

# ── Daemon enable / disable ───────────────────────────────────────────────────
# policy-daemon-enable-<unit>:  ensure the unit is enabled and running.
#   Leaving the group reverts: unit is disabled and stopped.
# policy-daemon-disable-<unit>: ensure the unit is disabled and stopped.
#   Leaving the group reverts: unit is re-enabled and started.
# <unit> may omit the .service suffix; systemd accepts both forms.
# Conflicts (unit in both lists): logged as a warning, unit is left untouched.

DAEMON_ENABLE_STATE="$STATE_DIR/daemon-enabled"
DAEMON_DISABLE_STATE="$STATE_DIR/daemon-disabled"
[[ -f "$DAEMON_ENABLE_STATE"  ]] || touch "$DAEMON_ENABLE_STATE"
[[ -f "$DAEMON_DISABLE_STATE" ]] || touch "$DAEMON_DISABLE_STATE"

# Append .service only when the name has no unit-type suffix already.
_svc_unit() { [[ "$1" == *.* ]] && echo "$1" || echo "${1}.service"; }

_in_enable_list()  { local n="$1"; for s in "${ACTIVE_DAEMON_ENABLE[@]}";  do [[ "$s" == "$n" ]] && return 0; done; return 1; }
_in_disable_list() { local n="$1"; for s in "${ACTIVE_DAEMON_DISABLE[@]}"; do [[ "$s" == "$n" ]] && return 0; done; return 1; }

# Apply enable policies
for _SVC in "${ACTIVE_DAEMON_ENABLE[@]}"; do
    if _in_disable_list "$_SVC"; then
        warn "Conflict: '$_SVC' is in both daemon-enable and daemon-disable groups — skipped"
        continue
    fi
    _UNIT=$(_svc_unit "$_SVC")
    _EN=$(systemctl is-enabled "$_UNIT" 2>/dev/null || echo "not-found")
    _AC=$(systemctl is-active  "$_UNIT" 2>/dev/null || echo "inactive")
    if [[ "$_EN" != "enabled" || "$_AC" != "active" ]]; then
        log "Enabling service: $_UNIT (enabled=$_EN active=$_AC)"
        systemctl enable --now "$_UNIT" 2>/dev/null \
            && log "Service enabled: $_UNIT" \
            || warn "Failed to enable $_UNIT — unit may not exist on this host"
    fi
done

# Apply disable policies
for _SVC in "${ACTIVE_DAEMON_DISABLE[@]}"; do
    if _in_enable_list "$_SVC"; then
        continue  # conflict already warned above
    fi
    _UNIT=$(_svc_unit "$_SVC")
    _EN=$(systemctl is-enabled "$_UNIT" 2>/dev/null || echo "not-found")
    _AC=$(systemctl is-active  "$_UNIT" 2>/dev/null || echo "inactive")
    if [[ "$_EN" == "enabled" || "$_AC" == "active" ]]; then
        log "Disabling service: $_UNIT (enabled=$_EN active=$_AC)"
        systemctl disable --now "$_UNIT" 2>/dev/null \
            && log "Service disabled: $_UNIT" \
            || warn "Failed to disable $_UNIT — unit may not exist on this host"
    fi
done

# Revert: host left a daemon-enable group → disable and stop the service
while IFS= read -r _OLD; do
    [[ -z "$_OLD" ]] && continue
    if ! _in_enable_list "$_OLD"; then
        _UNIT=$(_svc_unit "$_OLD")
        log "Reverting enable policy: disabling $_UNIT (host left daemon-enable group)"
        systemctl disable --now "$_UNIT" 2>/dev/null \
            || warn "Failed to disable (revert) $_UNIT"
    fi
done < "$DAEMON_ENABLE_STATE"

# Revert: host left a daemon-disable group → re-enable and start the service
while IFS= read -r _OLD; do
    [[ -z "$_OLD" ]] && continue
    if ! _in_disable_list "$_OLD"; then
        _UNIT=$(_svc_unit "$_OLD")
        log "Reverting disable policy: enabling $_UNIT (host left daemon-disable group)"
        systemctl enable --now "$_UNIT" 2>/dev/null \
            || warn "Failed to enable (revert) $_UNIT"
    fi
done < "$DAEMON_DISABLE_STATE"

# Persist current state
if [[ ${#ACTIVE_DAEMON_ENABLE[@]} -gt 0 ]]; then
    printf '%s\n' "${ACTIVE_DAEMON_ENABLE[@]}" | sort -u > "$DAEMON_ENABLE_STATE"
else
    > "$DAEMON_ENABLE_STATE"
fi
if [[ ${#ACTIVE_DAEMON_DISABLE[@]} -gt 0 ]]; then
    printf '%s\n' "${ACTIVE_DAEMON_DISABLE[@]}" | sort -u > "$DAEMON_DISABLE_STATE"
else
    > "$DAEMON_DISABLE_STATE"
fi

log "Policy enforcement complete."