feat(user-agent-auth): add RSA and ECDSA auth key types
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Extend user-agent authentication to support Ed25519, ECDSA (secp256k1), and RSA (PSS+SHA-256) with minimal protocol and storage changes. Add key_type to auth requests and useragent_client, update key parsing/signature verification paths, and keep backward compatibility by treating UNSPECIFIED as Ed25519.
This commit is contained in:
2026-03-14 12:14:30 +01:00
parent a3c401194f
commit 6030f30901
20 changed files with 556 additions and 124 deletions

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@@ -42,7 +42,10 @@ argon2 = { version = "0.5.3", features = ["zeroize"] }
restructed = "0.2.2"
strum = { version = "0.27.2", features = ["derive"] }
pem = "3.0.6"
k256 = "0.13.4"
k256.workspace = true
rsa.workspace = true
sha2.workspace = true
spki.workspace = true
alloy.workspace = true
arbiter-tokens-registry.path = "../arbiter-tokens-registry"

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@@ -0,0 +1,2 @@
-- Not reversible without data loss; drop the column to revert
ALTER TABLE useragent_client DROP COLUMN key_type;

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@@ -0,0 +1 @@
ALTER TABLE useragent_client ADD COLUMN key_type INTEGER NOT NULL DEFAULT 1;

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@@ -1,13 +1,12 @@
use arbiter_proto::proto::user_agent::{
AuthChallengeRequest, AuthChallengeSolution, UserAgentRequest,
AuthChallengeRequest, AuthChallengeSolution, KeyType as ProtoKeyType, UserAgentRequest,
user_agent_request::Payload as UserAgentRequestPayload,
};
use ed25519_dalek::VerifyingKey;
use tracing::error;
use crate::actors::user_agent::{
UserAgentConnection,
auth::state::{AuthContext, AuthStateMachine}, session::UserAgentSession,
auth::state::{AuthContext, AuthPublicKey, AuthStateMachine}, session::UserAgentSession,
};
#[derive(thiserror::Error, Debug, PartialEq)]
@@ -37,28 +36,50 @@ pub enum Error {
mod state;
use state::*;
fn parse_pubkey(key_type: ProtoKeyType, pubkey: Vec<u8>) -> Result<AuthPublicKey, Error> {
match key_type {
// UNSPECIFIED treated as Ed25519 for backward compatibility
ProtoKeyType::Unspecified | ProtoKeyType::Ed25519 => {
let pubkey_bytes = pubkey.as_array().ok_or(Error::InvalidClientPubkeyLength)?;
let key = ed25519_dalek::VerifyingKey::from_bytes(pubkey_bytes)
.map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
Ok(AuthPublicKey::Ed25519(key))
}
ProtoKeyType::EcdsaSecp256k1 => {
// Public key is sent as 33-byte SEC1 compressed point
let key = k256::ecdsa::VerifyingKey::from_sec1_bytes(&pubkey)
.map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
Ok(AuthPublicKey::EcdsaSecp256k1(key))
}
ProtoKeyType::Rsa => {
use rsa::pkcs8::DecodePublicKey as _;
let key = rsa::RsaPublicKey::from_public_key_der(&pubkey)
.map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
Ok(AuthPublicKey::Rsa(key))
}
}
}
fn parse_auth_event(payload: UserAgentRequestPayload) -> Result<AuthEvents, Error> {
match payload {
UserAgentRequestPayload::AuthChallengeRequest(AuthChallengeRequest {
pubkey,
bootstrap_token: None,
key_type,
}) => {
let pubkey_bytes = pubkey.as_array().ok_or(Error::InvalidClientPubkeyLength)?;
let pubkey = VerifyingKey::from_bytes(pubkey_bytes)
.map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
let kt = ProtoKeyType::try_from(key_type).unwrap_or(ProtoKeyType::Unspecified);
Ok(AuthEvents::AuthRequest(ChallengeRequest {
pubkey: pubkey.into(),
pubkey: parse_pubkey(kt, pubkey)?,
}))
}
UserAgentRequestPayload::AuthChallengeRequest(AuthChallengeRequest {
pubkey,
bootstrap_token: Some(token),
key_type,
}) => {
let pubkey_bytes = pubkey.as_array().ok_or(Error::InvalidClientPubkeyLength)?;
let pubkey = VerifyingKey::from_bytes(pubkey_bytes)
.map_err(|_| Error::InvalidAuthPubkeyEncoding)?;
let kt = ProtoKeyType::try_from(key_type).unwrap_or(ProtoKeyType::Unspecified);
Ok(AuthEvents::BootstrapAuthRequest(BootstrapAuthRequest {
pubkey: pubkey.into(),
pubkey: parse_pubkey(kt, pubkey)?,
token,
}))
}
@@ -71,11 +92,11 @@ fn parse_auth_event(payload: UserAgentRequestPayload) -> Result<AuthEvents, Erro
}
}
pub async fn authenticate(props: &mut UserAgentConnection) -> Result<VerifyingKey, Error> {
pub async fn authenticate(props: &mut UserAgentConnection) -> Result<AuthPublicKey, Error> {
let mut state = AuthStateMachine::new(AuthContext::new(props));
loop {
// This is needed because `state` now holds mutable reference to `ConnectionProps`, so we can't directly access `props` here
// `state` holds a mutable reference to `props` so we can't access it directly here
let transport = state.context_mut().conn.transport.as_mut();
let Some(UserAgentRequest {
payload: Some(payload),
@@ -110,9 +131,8 @@ pub async fn authenticate(props: &mut UserAgentConnection) -> Result<VerifyingKe
}
}
pub async fn authenticate_and_create(mut props: UserAgentConnection) -> Result<UserAgentSession, Error> {
let key = authenticate(&mut props).await?;
let session = UserAgentSession::new(props, key.clone());
let _key = authenticate(&mut props).await?;
let session = UserAgentSession::new(props);
Ok(session)
}

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@@ -1,30 +1,64 @@
use arbiter_proto::proto::user_agent::{
AuthChallenge, UserAgentResponse,
user_agent_response::Payload as UserAgentResponsePayload,
AuthChallenge, UserAgentResponse, user_agent_response::Payload as UserAgentResponsePayload,
};
use diesel::{ExpressionMethods as _, OptionalExtension as _, QueryDsl, update};
use diesel_async::RunQueryDsl;
use ed25519_dalek::VerifyingKey;
use tracing::error;
use super::Error;
use crate::{
actors::{bootstrap::ConsumeToken, user_agent::UserAgentConnection},
db::schema,
db::{models::KeyType, schema},
};
/// Abstraction over Ed25519 / ECDSA-secp256k1 / RSA public keys used during the auth handshake.
#[derive(Clone)]
pub enum AuthPublicKey {
Ed25519(ed25519_dalek::VerifyingKey),
/// Compressed SEC1 public key; signature bytes are raw 64-byte (r||s).
EcdsaSecp256k1(k256::ecdsa::VerifyingKey),
/// RSA-2048+ public key; signature bytes are PSS+SHA-256.
Rsa(rsa::RsaPublicKey),
}
impl AuthPublicKey {
/// Canonical bytes stored in DB and echoed back in the challenge.
/// Ed25519: raw 32 bytes. ECDSA: SEC1 compressed 33 bytes. RSA: DER-encoded SPKI.
pub fn to_stored_bytes(&self) -> Vec<u8> {
match self {
AuthPublicKey::Ed25519(k) => k.to_bytes().to_vec(),
// SEC1 compressed (33 bytes) is the natural compact format for secp256k1
AuthPublicKey::EcdsaSecp256k1(k) => k.to_encoded_point(true).as_bytes().to_vec(),
AuthPublicKey::Rsa(k) => {
use rsa::pkcs8::EncodePublicKey as _;
k.to_public_key_der()
.expect("rsa SPKI encoding is infallible")
.to_vec()
}
}
}
pub fn key_type(&self) -> KeyType {
match self {
AuthPublicKey::Ed25519(_) => KeyType::Ed25519,
AuthPublicKey::EcdsaSecp256k1(_) => KeyType::EcdsaSecp256k1,
AuthPublicKey::Rsa(_) => KeyType::Rsa,
}
}
}
pub struct ChallengeRequest {
pub pubkey: VerifyingKey,
pub pubkey: AuthPublicKey,
}
pub struct BootstrapAuthRequest {
pub pubkey: VerifyingKey,
pub pubkey: AuthPublicKey,
pub token: String,
}
pub struct ChallengeContext {
pub challenge: AuthChallenge,
pub key: VerifyingKey,
pub key: AuthPublicKey,
}
pub struct ChallengeSolution {
@@ -36,8 +70,8 @@ smlang::statemachine!(
custom_error: true,
transitions: {
*Init + AuthRequest(ChallengeRequest) / async prepare_challenge = SentChallenge(ChallengeContext),
Init + BootstrapAuthRequest(BootstrapAuthRequest) [async verify_bootstrap_token] / provide_key_bootstrap = AuthOk(VerifyingKey),
SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) [async verify_solution] / provide_key = AuthOk(VerifyingKey),
Init + BootstrapAuthRequest(BootstrapAuthRequest) [async verify_bootstrap_token] / provide_key_bootstrap = AuthOk(AuthPublicKey),
SentChallenge(ChallengeContext) + ReceivedSolution(ChallengeSolution) [async verify_solution] / provide_key = AuthOk(AuthPublicKey),
}
);
@@ -76,7 +110,9 @@ async fn create_nonce(db: &crate::db::DatabasePool, pubkey_bytes: &[u8]) -> Resu
})
}
async fn register_key(db: &crate::db::DatabasePool, pubkey_bytes: &[u8]) -> Result<(), Error> {
async fn register_key(db: &crate::db::DatabasePool, pubkey: &AuthPublicKey) -> Result<(), Error> {
let pubkey_bytes = pubkey.to_stored_bytes();
let key_type = pubkey.key_type();
let mut conn = db.get().await.map_err(|e| {
error!(error = ?e, "Database pool error");
Error::DatabasePoolUnavailable
@@ -84,8 +120,9 @@ async fn register_key(db: &crate::db::DatabasePool, pubkey_bytes: &[u8]) -> Resu
diesel::insert_into(schema::useragent_client::table)
.values((
schema::useragent_client::public_key.eq(pubkey_bytes.to_vec()),
schema::useragent_client::public_key.eq(pubkey_bytes),
schema::useragent_client::nonce.eq(1),
schema::useragent_client::key_type.eq(key_type),
))
.execute(&mut conn)
.await
@@ -115,15 +152,34 @@ impl AuthStateMachineContext for AuthContext<'_> {
ChallengeContext { challenge, key }: &ChallengeContext,
ChallengeSolution { solution }: &ChallengeSolution,
) -> Result<bool, Self::Error> {
let formatted_challenge =
arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
let formatted = arbiter_proto::format_challenge(challenge.nonce, &challenge.pubkey);
let signature = solution.as_slice().try_into().map_err(|_| {
error!(?solution, "Invalid signature length");
Error::InvalidChallengeSolution
})?;
let valid = key.verify_strict(&formatted_challenge, &signature).is_ok();
let valid = match key {
AuthPublicKey::Ed25519(vk) => {
let sig = solution.as_slice().try_into().map_err(|_| {
error!(?solution, "Invalid Ed25519 signature length");
Error::InvalidChallengeSolution
})?;
vk.verify_strict(&formatted, &sig).is_ok()
}
AuthPublicKey::EcdsaSecp256k1(vk) => {
use k256::ecdsa::signature::Verifier as _;
let sig = k256::ecdsa::Signature::try_from(solution.as_slice()).map_err(|_| {
error!(?solution, "Invalid ECDSA signature bytes");
Error::InvalidChallengeSolution
})?;
vk.verify(&formatted, &sig).is_ok()
}
AuthPublicKey::Rsa(pk) => {
use rsa::signature::Verifier as _;
let verifying_key = rsa::pss::VerifyingKey::<sha2::Sha256>::new(pk.clone());
let sig = rsa::pss::Signature::try_from(solution.as_slice()).map_err(|_| {
error!(?solution, "Invalid RSA signature bytes");
Error::InvalidChallengeSolution
})?;
verifying_key.verify(&formatted, &sig).is_ok()
}
};
Ok(valid)
}
@@ -132,10 +188,11 @@ impl AuthStateMachineContext for AuthContext<'_> {
&mut self,
ChallengeRequest { pubkey }: ChallengeRequest,
) -> Result<ChallengeContext, Self::Error> {
let nonce = create_nonce(&self.conn.db, pubkey.as_bytes()).await?;
let stored_bytes = pubkey.to_stored_bytes();
let nonce = create_nonce(&self.conn.db, &stored_bytes).await?;
let challenge = AuthChallenge {
pubkey: pubkey.as_bytes().to_vec(),
pubkey: stored_bytes,
nonce,
};
@@ -171,16 +228,16 @@ impl AuthStateMachineContext for AuthContext<'_> {
})
.await
.map_err(|e| {
error!(?pubkey, "Failed to consume bootstrap token: {e}");
error!(?e, "Failed to consume bootstrap token");
Error::BootstrapperActorUnreachable
})?;
if !token_ok {
error!(?pubkey, "Invalid bootstrap token provided");
error!("Invalid bootstrap token provided");
return Err(Error::InvalidBootstrapToken);
}
register_key(&self.conn.db, pubkey.as_bytes()).await?;
register_key(&self.conn.db, pubkey).await?;
Ok(true)
}
@@ -188,7 +245,7 @@ impl AuthStateMachineContext for AuthContext<'_> {
fn provide_key_bootstrap(
&mut self,
event_data: BootstrapAuthRequest,
) -> Result<VerifyingKey, Self::Error> {
) -> Result<AuthPublicKey, Self::Error> {
Ok(event_data.pubkey)
}
@@ -196,7 +253,45 @@ impl AuthStateMachineContext for AuthContext<'_> {
&mut self,
state_data: &ChallengeContext,
_: ChallengeSolution,
) -> Result<VerifyingKey, Self::Error> {
Ok(state_data.key)
) -> Result<AuthPublicKey, Self::Error> {
// ChallengeContext.key cannot be taken by value because smlang passes it by ref;
// we reconstruct stored bytes and return them wrapped in Ed25519 placeholder.
// Session uses only the raw bytes, so we carry them via a Vec<u8>.
// IMPORTANT: do NOT simplify this by storing the key type separately — the
// `AuthPublicKey` enum IS the source of truth for key bytes and type.
//
// smlang state-machine trait requires returning an owned value from `provide_key`,
// but `state_data` is only available by shared reference here. We extract the
// stored bytes and re-wrap as the correct variant so the caller can call
// `to_stored_bytes()` / `key_type()` without losing information.
let bytes = state_data.challenge.pubkey.clone();
let key_type = state_data.key.key_type();
let rebuilt = match key_type {
crate::db::models::KeyType::Ed25519 => {
let arr: &[u8; 32] = bytes
.as_slice()
.try_into()
.expect("ed25519 pubkey must be 32 bytes in challenge");
AuthPublicKey::Ed25519(
ed25519_dalek::VerifyingKey::from_bytes(arr)
.expect("key was already validated in parse_auth_event"),
)
}
crate::db::models::KeyType::EcdsaSecp256k1 => {
// bytes are SEC1 compressed (33 bytes produced by to_encoded_point(true))
AuthPublicKey::EcdsaSecp256k1(
k256::ecdsa::VerifyingKey::from_sec1_bytes(&bytes)
.expect("ecdsa key was already validated in parse_auth_event"),
)
}
crate::db::models::KeyType::Rsa => {
use rsa::pkcs8::DecodePublicKey as _;
AuthPublicKey::Rsa(
rsa::RsaPublicKey::from_public_key_der(&bytes)
.expect("rsa key was already validated in parse_auth_event"),
)
}
};
Ok(rebuilt)
}
}

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@@ -3,17 +3,15 @@ use std::{ops::DerefMut, sync::Mutex};
use arbiter_proto::proto::{
evm as evm_proto,
user_agent::{
ClientConnectionCancel, ClientConnectionRequest, UnsealEncryptedKey, UnsealResult, UnsealStart, UnsealStartResponse, UserAgentRequest,
UserAgentResponse, user_agent_request::Payload as UserAgentRequestPayload,
ClientConnectionCancel, ClientConnectionRequest, UnsealEncryptedKey, UnsealResult,
UnsealStart, UnsealStartResponse, UserAgentRequest, UserAgentResponse,
user_agent_request::Payload as UserAgentRequestPayload,
user_agent_response::Payload as UserAgentResponsePayload,
},
};
use chacha20poly1305::{AeadInPlace, XChaCha20Poly1305, XNonce, aead::KeyInit};
use ed25519_dalek::VerifyingKey;
use kameo::{
Actor,
error::SendError, messages, prelude::Context,
};
use kameo::{Actor, error::SendError, messages, prelude::Context};
use memsafe::MemSafe;
use tokio::{select, sync::watch};
use tracing::{error, info};
@@ -41,15 +39,13 @@ pub enum Error {
pub struct UserAgentSession {
props: UserAgentConnection,
key: VerifyingKey,
state: UserAgentStateMachine<DummyContext>,
}
impl UserAgentSession {
pub(crate) fn new(props: UserAgentConnection, key: VerifyingKey) -> Self {
pub(crate) fn new(props: UserAgentConnection) -> Self {
Self {
props,
key,
state: UserAgentStateMachine::new(DummyContext),
}
}
@@ -114,7 +110,7 @@ impl UserAgentSession {
#[messages]
impl UserAgentSession {
// TODO: Think about refactoring it to state-machine based flow, as we already have one
// TODO: Think about refactoring it to state-machine based flow, as we already have one
#[message(ctx)]
pub async fn request_new_client_approval(
&mut self,
@@ -123,12 +119,9 @@ impl UserAgentSession {
ctx: &mut Context<Self, Result<bool, Error>>,
) -> Result<bool, Error> {
self.send_msg(
UserAgentResponsePayload::ClientConnectionRequest(
ClientConnectionRequest {
pubkey: client_pubkey.as_bytes().to_vec(),
}
.into(),
),
UserAgentResponsePayload::ClientConnectionRequest(ClientConnectionRequest {
pubkey: client_pubkey.as_bytes().to_vec(),
}),
ctx,
)
.await?;
@@ -150,12 +143,12 @@ impl UserAgentSession {
UserAgentResponsePayload::ClientConnectionCancel(ClientConnectionCancel {}),
ctx,
).await?;
return Ok(false);
Ok(false)
}
result = self.expect_msg(extractor, ctx) => {
let result = result?;
info!(actor = "useragent", "received client connection approval result: approved={}", result.approved);
return Ok(result.approved);
Ok(result.approved)
}
}
}
@@ -420,10 +413,8 @@ impl UserAgentSession {
use arbiter_proto::transport::DummyTransport;
let transport: super::Transport = Box::new(DummyTransport::new());
let props = UserAgentConnection::new(db, actors, transport);
let key = VerifyingKey::from_bytes(&[0u8; 32]).unwrap();
Self {
props,
key,
state: UserAgentStateMachine::new(DummyContext),
}
}

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@@ -135,10 +135,10 @@ pub async fn create_test_pool() -> DatabasePool {
let tempfile_name = Alphanumeric.sample_string(&mut rand::rng(), 16);
let file = std::env::temp_dir().join(tempfile_name);
let url = format!(
"{}?mode=rwc",
file.to_str().expect("temp file path is not valid UTF-8")
);
let url = file
.to_str()
.expect("temp file path is not valid UTF-8")
.to_string();
create_pool(Some(&url))
.await

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@@ -12,8 +12,6 @@ use diesel::{prelude::*, sqlite::Sqlite};
use restructed::Models;
pub mod types {
use std::os::unix;
use chrono::{DateTime, Utc};
use diesel::{
deserialize::{FromSql, FromSqlRow},
@@ -74,6 +72,43 @@ pub mod types {
Ok(SqliteTimestamp(datetime))
}
}
/// Key algorithm stored in the `useragent_client.key_type` column.
/// Values must stay stable — they are persisted in the database.
#[derive(Debug, Clone, Copy, PartialEq, Eq, FromSqlRow, AsExpression)]
#[diesel(sql_type = Integer)]
#[repr(i32)]
pub enum KeyType {
Ed25519 = 1,
EcdsaSecp256k1 = 2,
Rsa = 3,
}
impl ToSql<Integer, Sqlite> for KeyType {
fn to_sql<'b>(
&'b self,
out: &mut diesel::serialize::Output<'b, '_, Sqlite>,
) -> diesel::serialize::Result {
out.set_value(*self as i32);
Ok(IsNull::No)
}
}
impl FromSql<Integer, Sqlite> for KeyType {
fn from_sql(
mut bytes: <Sqlite as diesel::backend::Backend>::RawValue<'_>,
) -> diesel::deserialize::Result<Self> {
let Some(SqliteType::Long) = bytes.value_type() else {
return Err("Expected Integer for KeyType".into());
};
match bytes.read_long() {
1 => Ok(KeyType::Ed25519),
2 => Ok(KeyType::EcdsaSecp256k1),
3 => Ok(KeyType::Rsa),
other => Err(format!("Unknown KeyType discriminant: {other}").into()),
}
}
}
}
pub use types::*;
@@ -171,6 +206,7 @@ pub struct UseragentClient {
pub public_key: Vec<u8>,
pub created_at: SqliteTimestamp,
pub updated_at: SqliteTimestamp,
pub key_type: KeyType,
}
#[derive(Models, Queryable, Debug, Insertable, Selectable)]

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@@ -153,6 +153,7 @@ diesel::table! {
public_key -> Binary,
created_at -> Integer,
updated_at -> Integer,
key_type -> Integer,
}
}

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@@ -1,5 +1,5 @@
use arbiter_proto::proto::user_agent::{
AuthChallengeRequest, AuthChallengeSolution, UserAgentRequest,
AuthChallengeRequest, AuthChallengeSolution, KeyType as ProtoKeyType, UserAgentRequest,
user_agent_request::Payload as UserAgentRequestPayload,
user_agent_response::Payload as UserAgentResponsePayload,
};
@@ -38,6 +38,7 @@ pub async fn test_bootstrap_token_auth() {
AuthChallengeRequest {
pubkey: pubkey_bytes,
bootstrap_token: Some(token),
key_type: ProtoKeyType::Ed25519.into(),
},
)),
})
@@ -74,6 +75,7 @@ pub async fn test_bootstrap_invalid_token_auth() {
AuthChallengeRequest {
pubkey: pubkey_bytes,
bootstrap_token: Some("invalid_token".to_string()),
key_type: ProtoKeyType::Ed25519.into(),
},
)),
})
@@ -102,10 +104,14 @@ pub async fn test_challenge_auth() {
let new_key = ed25519_dalek::SigningKey::generate(&mut rand::rng());
let pubkey_bytes = new_key.verifying_key().to_bytes().to_vec();
// Pre-register key with key_type
{
let mut conn = db.get().await.unwrap();
insert_into(schema::useragent_client::table)
.values(schema::useragent_client::public_key.eq(pubkey_bytes.clone()))
.values((
schema::useragent_client::public_key.eq(pubkey_bytes.clone()),
schema::useragent_client::key_type.eq(1i32),
))
.execute(&mut conn)
.await
.unwrap();
@@ -122,6 +128,7 @@ pub async fn test_challenge_auth() {
AuthChallengeRequest {
pubkey: pubkey_bytes,
bootstrap_token: None,
key_type: ProtoKeyType::Ed25519.into(),
},
)),
})