boxmaker/crates/brokerd/tests/ledger.rs

//! The ledger's first and third steps: decide and record; raise the state and record the result.
//! And what happens after a failed append or a panic. Do not edit.

#[path = "support/build.rs"]
mod build;
#[path = "support/rig.rs"]
mod rig;
#[path = "support/sink.rs"]
mod sink;
#[path = "support/tmp.rs"]
mod tmp;

use std::os::unix::fs::PermissionsExt;
use std::panic::AssertUnwindSafe;

use brokerd::ledger::{Call, Decided, Grants, NOT_RECORDED, POISONED, STOPPED};
use brokerd::policy::{Label, SessionState};
use build::{grant, now, read, set};
use proto::{
    AuditEvent, CallId, DataClass, DecisionRecord, DenyReason, GrantProblem, Mode, ResultStatus,
    SessionId, ToolResponse,
};
use rig::Rig;

fn one(grants: Vec<build::Build>) -> Grants {
    Ok(set(grants))
}

fn notes(mode: Mode) -> Grants {
    one(vec![grant("n", "read_file", mode).paths(&["/n"])])
}

fn call(label: Label) -> Call {
    Call {
        session: SessionId::new("s1").unwrap(),
        call: CallId(1),
        decision: 0,
        label,
    }
}

fn secret() -> Label {
    Label {
        class: DataClass::Secret,
        untrusted: true,
    }
}

fn result(content: &str, label: Label) -> ToolResponse {
    ToolResponse::Result {
        content: content.to_string(),
        class: label.class,
        untrusted: label.untrusted,
        truncated: false,
    }
}

#[test]
fn an_allowed_call_is_recorded_in_full() {
    let rig = Rig::new("ledger-allowed");
    let ledger = rig.ledger();
    let request = read("/n/a");
    let arguments = request.arguments.clone();
    match ledger.decide(request, &notes(Mode::Auto), now()) {
        Decided::Allowed { decision, seq } => {
            assert_eq!(seq, 0);
            assert_eq!(decision.grant(), "n");
        }
        other => panic!("{other:?}"),
    }
    let records = rig.records();
    assert_eq!(records.len(), 1);
    assert_eq!(records[0].time, now());
    assert_eq!(
        records[0].event,
        AuditEvent::Decision {
            session: SessionId::new("s1").unwrap(),
            call: CallId(1),
            tool: "read_file".to_string(),
            arguments,
            outcome: DecisionRecord::Allowed {},
            grant: Some("n".to_string()),
            grant_sha256: Some(proto::sha256(b"n").unwrap()),
            taint: DataClass::Private,
            untrusted: false,
        }
    );
}

#[test]
fn an_ask_is_recorded_as_ask_with_the_state_it_was_decided_at() {
    let rig = Rig::new("ledger-ask");
    let ledger = rig.ledger();
    match ledger.decide(read("/n/a"), &notes(Mode::Ask), now()) {
        Decided::Ask { ask, seq, state } => {
            assert_eq!((seq, ask.grant()), (0, "n"));
            assert_eq!(state, SessionState::default());
        }
        other => panic!("{other:?}"),
    }
    match &rig.events()[0] {
        AuditEvent::Decision { outcome, grant, .. } => {
            assert_eq!(*outcome, DecisionRecord::Ask {});
            assert_eq!(grant.as_deref(), Some("n"));
        }
        other => panic!("{other:?}"),
    }
}

#[test]
fn a_denial_names_a_grant_only_when_a_grant_denied() {
    let rig = Rig::new("ledger-denied");
    let ledger = rig.ledger();
    let none = ledger.decide(read("/n/a"), &one(Vec::new()), now());
    assert!(
        matches!(none, Decided::Denied(DenyReason::NoGrant)),
        "{none:?}"
    );
    let deny = one(vec![grant("d", "read_file", Mode::Deny).paths(&["/n"])]);
    let by = ledger.decide(read("/n/a"), &deny, now());
    assert!(
        matches!(by, Decided::Denied(DenyReason::DeniedByGrant)),
        "{by:?}"
    );
    let events = rig.events();
    let named: Vec<(DecisionRecord, Option<String>)> = events
        .iter()
        .map(|e| match e {
            AuditEvent::Decision { outcome, grant, .. } => (outcome.clone(), grant.clone()),
            other => panic!("{other:?}"),
        })
        .collect();
    assert_eq!(
        named,
        [
            (
                DecisionRecord::Denied {
                    reason: DenyReason::NoGrant
                },
                None
            ),
            (
                DecisionRecord::Denied {
                    reason: DenyReason::DeniedByGrant
                },
                Some("d".to_string())
            ),
        ]
    );
}

#[test]
fn invalid_grants_come_first_then_an_unreadable_state() {
    let rig = Rig::new("ledger-order");
    let ledger = rig.ledger();
    std::fs::create_dir_all(rig.cfg.state_dir()).unwrap();
    std::fs::write(rig.state_file("s1"), "not json").unwrap();
    let invalid: Grants = Err(vec![GrantProblem {
        file: "x.toml".to_string(),
        line: None,
        problem: "bad".to_string(),
    }]);
    let first = ledger.decide(read("/n/a"), &invalid, now());
    assert!(
        matches!(first, Decided::Denied(DenyReason::GrantsInvalid)),
        "{first:?}"
    );
    let second = ledger.decide(read("/n/a"), &notes(Mode::Auto), now());
    assert!(
        matches!(second, Decided::Denied(DenyReason::StateUnreadable)),
        "{second:?}"
    );
    // A state brokerd cannot read is recorded as the most sensitive one.
    for event in rig.events() {
        match event {
            AuditEvent::Decision {
                taint, untrusted, ..
            } => assert_eq!((taint, untrusted), (DataClass::Secret, true)),
            other => panic!("{other:?}"),
        }
    }
    let damaged = rig.lines.with("see docs/runbook.md#broker-state-damaged");
    assert!(!damaged.is_empty(), "{:?}", rig.lines.all());
}

#[test]
fn a_failed_append_denies_this_call_and_every_later_one() {
    let rig = Rig::new("ledger-stop");
    let ledger = rig.ledger();
    rig.switch.fail(true);
    let first = ledger.decide(read("/n/a"), &notes(Mode::Auto), now());
    assert!(
        matches!(first, Decided::Denied(DenyReason::AuditUnavailable)),
        "{first:?}"
    );
    assert_eq!(rig.switch.attempts(), 1);
    // The sink would work again; the ledger does not try it.
    rig.switch.fail(false);
    let later = ledger.decide(read("/n/a"), &notes(Mode::Auto), now());
    assert!(
        matches!(later, Decided::Denied(DenyReason::AuditUnavailable)),
        "{later:?}"
    );
    let finished = ledger.finish(&call(secret()), result("x", secret()), now());
    assert_eq!(
        finished,
        ToolResponse::Failed {
            message: NOT_RECORDED.to_string()
        }
    );
    assert_eq!(rig.switch.attempts(), 1, "nothing more was written");
    assert!(rig.records().is_empty());
    assert!(!rig.state_file("s1").exists(), "the state was not raised");
    assert!(!rig.lines.with(STOPPED).is_empty());
    assert!(
        rig.lines
            .all()
            .iter()
            .all(|l| !l.contains("runbook") || l.ends_with("see docs/runbook.md#audit-unavailable")),
        "{:?}",
        rig.lines.all()
    );
}

#[test]
fn a_panic_while_holding_the_ledger_denies_every_later_call() {
    let rig = Rig::new("ledger-poison");
    let ledger = rig.ledger();
    rig.switch.panic_next();
    let panicked = std::panic::catch_unwind(AssertUnwindSafe(|| {
        ledger.decide(read("/n/a"), &notes(Mode::Auto), now())
    }));
    assert!(panicked.is_err());
    let later = ledger.decide(read("/n/a"), &notes(Mode::Auto), now());
    assert!(
        matches!(later, Decided::Denied(DenyReason::AuditUnavailable)),
        "{later:?}"
    );
    assert_eq!(rig.switch.attempts(), 1);
    assert!(
        !rig.lines.with(POISONED).is_empty(),
        "{:?}",
        rig.lines.all()
    );
    assert!(POISONED.ends_with("see docs/runbook.md#audit-unavailable"));
}

#[test]
fn a_result_raises_the_state_then_is_recorded() {
    let rig = Rig::new("ledger-result");
    let ledger = rig.ledger();
    let answer = ledger.finish(&call(secret()), result("key", secret()), now());
    assert_eq!(answer, result("key", secret()), "passed on unchanged");
    let state = rig.state().read(&SessionId::new("s1").unwrap()).unwrap();
    assert_eq!(
        state,
        SessionState {
            taint: DataClass::Secret,
            untrusted: true
        }
    );
    assert_eq!(
        rig.events(),
        [AuditEvent::Result {
            session: SessionId::new("s1").unwrap(),
            call: CallId(1),
            decision: 0,
            status: ResultStatus::Result,
            class: DataClass::Secret,
            untrusted: true,
            truncated: false,
            bytes: 3,
            sha256: proto::sha256(b"key").unwrap(),
            taint_after: DataClass::Secret,
        }]
    );
}

#[test]
fn taint_never_goes_down() {
    let rig = Rig::new("ledger-down");
    let ledger = rig.ledger();
    let public = Label {
        class: DataClass::Public,
        untrusted: false,
    };
    ledger.finish(&call(secret()), result("a", secret()), now());
    ledger.finish(&call(public), result("b", public), now());
    let after: Vec<DataClass> = rig
        .events()
        .iter()
        .map(|e| match e {
            AuditEvent::Result { taint_after, .. } => *taint_after,
            other => panic!("{other:?}"),
        })
        .collect();
    assert_eq!(after, [DataClass::Secret, DataClass::Secret]);
    let state = rig.state().read(&SessionId::new("s1").unwrap()).unwrap();
    assert_eq!((state.taint, state.untrusted), (DataClass::Secret, true));
}

#[test]
fn a_failure_changes_no_state_and_is_recorded_by_its_message() {
    let rig = Rig::new("ledger-failed");
    let ledger = rig.ledger();
    let failed = ToolResponse::Failed {
        message: "the tool timed out".to_string(),
    };
    assert_eq!(
        ledger.finish(&call(secret()), failed.clone(), now()),
        failed
    );
    assert!(!rig.state_file("s1").exists());
    match &rig.events()[0] {
        AuditEvent::Result {
            status,
            class,
            bytes,
            sha256,
            taint_after,
            ..
        } => {
            assert_eq!(*status, ResultStatus::Failed);
            assert_eq!(
                *class,
                DataClass::Secret,
                "the label the result would have had"
            );
            assert_eq!(*bytes, 18);
            assert_eq!(*sha256, proto::sha256(b"the tool timed out").unwrap());
            assert_eq!(*taint_after, DataClass::Private, "the taint before");
        }
        other => panic!("{other:?}"),
    }
}

#[test]
fn a_state_that_cannot_be_written_withholds_the_content() {
    if tmp::running_as_root("a_state_that_cannot_be_written_withholds_the_content") {
        return;
    }
    let rig = Rig::new("ledger-ro");
    let ledger = rig.ledger();
    let dir = rig.cfg.state_dir();
    std::fs::create_dir_all(&dir).unwrap();
    std::fs::set_permissions(&dir, std::fs::Permissions::from_mode(0o500)).unwrap();
    let answer = ledger.finish(&call(secret()), result("key", secret()), now());
    std::fs::set_permissions(&dir, std::fs::Permissions::from_mode(0o700)).unwrap();
    assert_eq!(
        answer,
        ToolResponse::Failed {
            message: NOT_RECORDED.to_string()
        }
    );
    assert!(
        rig.records().is_empty(),
        "no Result for a state not on disk"
    );
    assert!(
        !rig.lines
            .with("see docs/runbook.md#broker-state-damaged")
            .is_empty()
    );
}

#[test]
fn a_result_record_that_cannot_be_written_withholds_the_content() {
    let rig = Rig::new("ledger-norecord");
    let ledger = rig.ledger();
    rig.switch.fail(true);
    let answer = ledger.finish(&call(secret()), result("key", secret()), now());
    assert_eq!(
        answer,
        ToolResponse::Failed {
            message: NOT_RECORDED.to_string()
        }
    );
    assert!(
        !rig.lines
            .with("see docs/runbook.md#audit-unavailable")
            .is_empty()
    );
}