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//! Certificate related types and functions for an arti relay.
use tor_cert::{CertEncodeError, CertType, CertifiedKey, Ed25519Cert, EncodedEd25519Cert};
use tor_checkable::{SelfSigned, Timebound};
use tor_key_forge::{InvalidCertError, ParsedEd25519Cert, ToEncodableCert};
use tor_llcrypto::pk::ed25519::{self, Ed25519Identity};
use web_time_compat::{SystemTime, SystemTimeExt};
use crate::pk::{RelayIdentityKeypair, RelayLinkSigningKeypair, RelaySigningKeypair};
// TODO: maybe we can eventually unify the 2 `gen_*_cert` functions
// into a single one taking a `K: HasCertType` generic param and returning `Result<K>`.
// That way, we could call `K::cert_type()` to get the cert type,
// making it impossible for the `gen_*_cert function to accidentally use
// a different cert type than the validation function.
/// Generate the relay signing certificate from the given relay identity keypair and the relay
/// signing keypair.
pub fn gen_signing_cert(
kp_relay_id: &RelayIdentityKeypair,
kp_relaysign_id: &RelaySigningKeypair,
expiry: SystemTime,
) -> Result<RelaySigningKeyCert, CertEncodeError> {
Ed25519Cert::constructor()
.cert_type(RelaySigningKeyCert::cert_type())
.expiration(expiry)
.signing_key(kp_relay_id.to_ed25519_id())
.cert_key(CertifiedKey::Ed25519(kp_relaysign_id.to_ed25519_id()))
.encode_and_sign(kp_relay_id)
.map(RelaySigningKeyCert::from)
}
/// Generate the relay link certificate from the given relay signing keypair and the relay
/// link keypair.
pub fn gen_link_cert(
kp_link_id: &RelayLinkSigningKeypair,
) -> Result<RelayLinkSigningKeyCert, CertEncodeError> {
.cert_type(RelayLinkSigningKeyCert::cert_type())
.signing_key(kp_relaysign_id.to_ed25519_id())
.cert_key(CertifiedKey::Ed25519(kp_link_id.to_ed25519_id()))
.encode_and_sign(kp_relaysign_id)
.map(RelayLinkSigningKeyCert::from)
/// Generate the signed TLS certificate from the given relay signing keypair and the TLS cert
/// digest.
pub fn gen_tls_cert(
tls_digest: [u8; 32],
) -> Result<EncodedEd25519Cert, CertEncodeError> {
.cert_type(CertType::SIGNING_V_TLS_CERT)
.cert_key(CertifiedKey::X509Sha256Digest(tls_digest))
/// Certificate for the medium-term relay signing key (`K_relaysign_ed`).
///
/// This is an ed25519 certificate encoded in Tor's
/// [certificate format](https://spec.torproject.org/cert-spec.html#ed-certs)
/// with [`CERT_KEY_TYPE`](https://spec.torproject.org/cert-spec.html#list-key-types)
/// set to `ed25519` (`01`),
/// and the [`CERT_TYPE`](https://spec.torproject.org/cert-spec.html#list-cert-types)
/// set to `IDENTITY_V_SIGNING` (`04`).
/// The signing key is the relay identity key (`K_relayid_ed`)`).
#[derive(Debug, Clone, PartialEq, derive_more::From)]
pub struct RelaySigningKeyCert(EncodedEd25519Cert);
impl RelaySigningKeyCert {
/// Return the `CertType` of this cert.
fn cert_type() -> CertType {
CertType::IDENTITY_V_SIGNING
/// Certificate for the short-term signing keypair for link authentication.
/// set to `SIGNING_V_LINK_AUTH` (`06`).
pub struct RelayLinkSigningKeyCert(EncodedEd25519Cert);
impl RelayLinkSigningKeyCert {
CertType::SIGNING_V_LINK_AUTH
impl ToEncodableCert<RelaySigningKeypair> for RelaySigningKeyCert {
type ParsedCert = ParsedEd25519Cert;
type EncodableCert = EncodedEd25519Cert;
type SigningKey = RelayIdentityKeypair;
fn validate(
cert: Self::ParsedCert,
subject: &RelaySigningKeypair,
signed_with: &Self::SigningKey,
) -> Result<Self, InvalidCertError> {
// TODO: take the time/time provider as an arg?
let now = SystemTime::get();
validate_ed25519_cert(
cert,
&subject.public().into(),
&signed_with.public().into(),
Self::cert_type(),
&now,
)
fn to_encodable_cert(self) -> Self::EncodableCert {
self.0
impl ToEncodableCert<RelayLinkSigningKeypair> for RelayLinkSigningKeyCert {
type SigningKey = RelaySigningKeypair;
subject: &RelayLinkSigningKeypair,
/// Validate the specified `cert`, checking that
/// * its [`CertType`] is `cert_type, and
/// * its subject key is `subject`, and
/// * it is signed with the `signed_with` key, and
/// * it is timely (it is not expired or not yet valid at the specified `ts`)
fn validate_ed25519_cert(
cert: ParsedEd25519Cert,
subject: &ed25519::PublicKey,
signed_with: &ed25519::PublicKey,
cert_type: CertType,
ts: &SystemTime,
) -> Result<EncodedEd25519Cert, InvalidCertError> {
let cert = cert
.should_be_signed_with(&Ed25519Identity::from(signed_with))?
.check_signature()?;
let cert = cert.check_valid_at(ts)?;
let subject = Ed25519Identity::from(subject);
if subject != *cert.subject_key()? {
return Err(InvalidCertError::SubjectKeyMismatch);
let actual_cert_type = cert.as_ref().cert_type();
if actual_cert_type != cert_type {
return Err(InvalidCertError::CertType(actual_cert_type));
Ok(cert.into_encoded())