Classroom_Desktop/tests/test-classroom-network.sh

#!/bin/bash
# What the classroom account may and may not do to the network.
#
# The rule is plain JavaScript that polkitd evaluates, so it is evaluated
# here too, with polkit's own objects stubbed. That tests the part this
# package actually wrote: which action ids come back NO, for which user,
# and — just as important — which ones are deliberately left alone,
# because a rule that refuses too much takes the room off the network.
#
# What this canNOT test is the last mile: that a teacher sitting in a real
# Plasma session cannot reveal a saved password through the applet. polkit
# resolves a subject through logind, and a container has no graphical seat
# session for it to resolve, so every check here comes back denied for
# reasons that have nothing to do with this rule. docs/testing.md carries
# the physical procedure for that.
set -uo pipefail

ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"

if ! command -v node >/dev/null 2>&1; then
    echo "  SKIP node is not installed; the polkit rule was not evaluated"
    exit 0
fi

RULES="$ROOT/config/polkit/org.ekklesia.classroom.network.rules"
SLEEP_RULES="$ROOT/config/polkit/org.ekklesia.classroom.sleep.rules"
KDEGLOBALS="$ROOT/config/plasma/xdg/kdeglobals"
WIFI="$ROOT/scripts/classroom-wifi"

node - "$RULES" "$SLEEP_RULES" "$KDEGLOBALS" "$WIFI" <<'JS'
const fs = require("fs");
const [rulesPath, sleepPath, kdeglobalsPath, wifiPath] = process.argv.slice(2);

let passed = 0, failed = 0;
function check(label, condition, detail) {
    if (condition) { console.log("  ok   " + label); passed++; }
    else { console.log("  FAIL " + label); if (detail) console.log("       " + detail); failed++; }
}

// polkit's own surface, as far as these rules use it.
function loadRules(path) {
    const handlers = [];
    const polkit = {
        Result: {NO: "NO", YES: "YES", NOT_HANDLED: "NOT_HANDLED",
                 AUTH_ADMIN: "AUTH_ADMIN"},
        addRule: (fn) => handlers.push(fn),
        log: () => {},
    };
    const source = fs.readFileSync(path, "utf8");
    new Function("polkit", source)(polkit);
    return (actionId, user) => {
        for (const handler of handlers) {
            const result = handler({id: actionId}, {user: user});
            if (result !== polkit.Result.NOT_HANDLED) return result;
        }
        return "NOT_HANDLED";
    };
}

const decide = loadRules(rulesPath);

console.log("1. the classroom account cannot be shown a saved password");
// settings.modify.own is the one that matters. Debian ships it as "yes"
// for an active session: no prompt, no administrator, just the password.
// A network added from the desktop is user-owned, so this is the path a
// teacher would actually have.
check("a connection this user owns is refused",
      decide("org.freedesktop.NetworkManager.settings.modify.own", "classroom") === "NO");
check("a connection the system owns is refused",
      decide("org.freedesktop.NetworkManager.settings.modify.system", "classroom") === "NO");
check("the QR code that contains the pre-shared key is refused",
      decide("org.freedesktop.NetworkManager.wifi.share.protected", "classroom") === "NO");
check("and its open-network twin",
      decide("org.freedesktop.NetworkManager.wifi.share.open", "classroom") === "NO");

console.log("2. the room stays on the network");
// Refusing these would be a rule that protects a password by taking the
// classroom off the internet, which is not a trade this room can make.
for (const action of ["network-control", "wifi.scan",
                      "enable-disable-network", "enable-disable-wifi"]) {
    check(action + " is left alone",
          decide("org.freedesktop.NetworkManager." + action, "classroom") === "NOT_HANDLED");
}

console.log("3. an administrator keeps every one of them");
for (const user of ["tech", "root"]) {
    check(user + " is not touched by this rule",
          ["settings.modify.own", "settings.modify.system",
           "wifi.share.protected"].every(
              a => decide("org.freedesktop.NetworkManager." + a, user) === "NOT_HANDLED"));
}

console.log("4. machine-wide settings a room has no business changing");
for (const action of ["settings.modify.hostname", "settings.modify.global-dns",
                      "reload", "checkpoint-rollback"]) {
    check(action + " is refused",
          decide("org.freedesktop.NetworkManager." + action, "classroom") === "NO");
}

console.log("5. the sleep rule is unchanged by any of this");
const sleepDecide = loadRules(sleepPath);
check("the classroom still cannot suspend the room",
      sleepDecide("org.freedesktop.login1.suspend", "classroom") === "NO");
check("and a technician still can",
      sleepDecide("org.freedesktop.login1.suspend", "tech") === "NOT_HANDLED");
check("the network rule does not answer sleep",
      decide("org.freedesktop.login1.suspend", "classroom") === "NOT_HANDLED");

console.log("6. the panel is told not to offer doors that will not open");
const kdeglobals = fs.readFileSync(kdeglobalsPath, "utf8");
check("the network settings module is refused by Kiosk policy",
      /\[KDE Control Module Restrictions\]\[\$i\][\s\S]*?kcm_networkmanagement=false/.test(kdeglobals));
check("and the restriction is immutable, like the rest of the policy",
      /\[KDE Control Module Restrictions\]\[\$i\]/.test(kdeglobals));

console.log("7. the Wi-Fi an administrator provisions belongs to the machine");
const wifi = fs.readFileSync(wifiPath, "utf8");
// As a quoted nmcli argument, which is the only form that would actually
// set it. The prose above it in the script says the word on purpose.
check("no connection.permissions is passed to nmcli, so it is the machine's",
      !/"connection\.permissions"/.test(wifi),
      "a permissions argument would make the secrets readable by that user");
check("secrets are stored in the connection file, not a login keyring",
      /psk-flags[\s\S]{0,40}"0"/.test(wifi));
check("the password is prompted for, never taken from the command line",
      /getpass\.getpass/.test(wifi) && !/--psk/.test(wifi));
check("and it refuses to run as anybody but root",
      /geteuid\(\) != 0/.test(wifi));

console.log();
console.log(passed + " passed, " + failed + " failed");
process.exit(failed ? 1 : 0);
JS