feat(local_proxy): use ed25519 signatures with pg_session_jwt (#10290)

Generally ed25519 seems to be much preferred for cryptographic strength
to P256 nowadays, and it is NIST approved finally. We should use it
where we can as it's also faster than p256.

This PR makes the re-signed JWTs between local_proxy and pg_session_jwt
use ed25519.

This does introduce a new dependency on ed25519, but I do recall some
Neon Authorise customers asking for support for ed25519, so I am
justifying this dependency addition in the context that we can then
introduce support for customer ed25519 keys

sources:
* https://csrc.nist.gov/pubs/fips/186-5/final subsection 7 (EdDSA)
* https://datatracker.ietf.org/doc/html/rfc8037#section-3.1

proxy/src/serverless/backend.rs

@@ -3,9 +3,9 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use async_trait::async_trait;
+use ed25519_dalek::SigningKey;
 use hyper_util::rt::{TokioExecutor, TokioIo, TokioTimer};
-use p256::ecdsa::SigningKey;
-use p256::elliptic_curve::JwkEcKey;
+use jose_jwk::jose_b64;
 use rand::rngs::OsRng;
 use tokio::net::{lookup_host, TcpStream};
 use tracing::field::display;
@@ -354,9 +354,15 @@ impl PoolingBackend {
     }
 }
 
-fn create_random_jwk() -> (SigningKey, JwkEcKey) {
-    let key = SigningKey::random(&mut OsRng);
-    let jwk = p256::PublicKey::from(key.verifying_key()).to_jwk();
+fn create_random_jwk() -> (SigningKey, jose_jwk::Key) {
+    let key = SigningKey::generate(&mut OsRng);
+
+    let jwk = jose_jwk::Key::Okp(jose_jwk::Okp {
+        crv: jose_jwk::OkpCurves::Ed25519,
+        x: jose_b64::serde::Bytes::from(key.verifying_key().to_bytes().to_vec()),
+        d: None,
+    });
+
     (key, jwk)
 }
 

proxy/src/serverless/local_conn_pool.rs

@@ -16,17 +16,16 @@ use std::sync::Arc;
 use std::task::{ready, Poll};
 use std::time::Duration;
 
+use ed25519_dalek::{Signature, Signer, SigningKey};
 use futures::future::poll_fn;
 use futures::Future;
 use indexmap::IndexMap;
 use jose_jwk::jose_b64::base64ct::{Base64UrlUnpadded, Encoding};
-use p256::ecdsa::{Signature, SigningKey};
 use parking_lot::RwLock;
 use postgres_client::tls::NoTlsStream;
 use postgres_client::types::ToSql;
 use postgres_client::AsyncMessage;
 use serde_json::value::RawValue;
-use signature::Signer;
 use tokio::net::TcpStream;
 use tokio::time::Instant;
 use tokio_util::sync::CancellationToken;
@@ -42,7 +41,7 @@ use crate::control_plane::messages::{ColdStartInfo, MetricsAuxInfo};
 use crate::metrics::Metrics;
 
 pub(crate) const EXT_NAME: &str = "pg_session_jwt";
-pub(crate) const EXT_VERSION: &str = "0.1.2";
+pub(crate) const EXT_VERSION: &str = "0.2.0";
 pub(crate) const EXT_SCHEMA: &str = "auth";
 
 #[derive(Clone)]
@@ -339,8 +338,8 @@ fn sign_jwt(sk: &SigningKey, payload: &[u8]) -> String {
     let cap = jwt.capacity();
 
     // we only need an empty header with the alg specified.
-    // base64url(r#"{"alg":"ES256"}"#) == "eyJhbGciOiJFUzI1NiJ9"
-    jwt.push_str("eyJhbGciOiJFUzI1NiJ9.");
+    // base64url(r#"{"alg":"EdDSA"}"#) == "eyJhbGciOiJFZERTQSJ9"
+    jwt.push_str("eyJhbGciOiJFZERTQSJ9.");
 
     // encode the jwt payload in-place
     base64::encode_config_buf(payload, base64::URL_SAFE_NO_PAD, &mut jwt);
@@ -366,14 +365,14 @@ fn sign_jwt(sk: &SigningKey, payload: &[u8]) -> String {
 #[cfg(test)]
 #[expect(clippy::unwrap_used)]
 mod tests {
-    use p256::ecdsa::SigningKey;
+    use ed25519_dalek::SigningKey;
     use typed_json::json;
 
     use super::resign_jwt;
 
     #[test]
     fn jwt_token_snapshot() {
-        let key = SigningKey::from_bytes(&[1; 32].into()).unwrap();
+        let key = SigningKey::from_bytes(&[1; 32]);
         let data =
             json!({"foo":"bar","jti":"foo\nbar","nested":{"jti":"tricky nesting"}}).to_string();
 
@@ -381,12 +380,17 @@ mod tests {
 
         // To validate the JWT, copy the JWT string and paste it into https://jwt.io/.
         // In the public-key box, paste the following jwk public key
-        // `{"kty":"EC","crv":"P-256","x":"b_A7lJJBzh2t1DUZ5pYOCoW0GmmgXDKBA6orzhWUyhY","y":"PE91OlW_AdxT9sCwx-7ni0DG_30lqW4igrmJzvccFEo"}`
+        // `{"kty":"OKP","crv":"Ed25519","x":"iojj3XQJ8ZX9UtstPLpdcspnCb8dlBIb83SIAbQPb1w"}`
+        // Note - jwt.io doesn't support EdDSA :(
+        // https://github.com/jsonwebtoken/jsonwebtoken.github.io/issues/509
 
-        // let pub_key = p256::ecdsa::VerifyingKey::from(&key);
-        // let pub_key = p256::PublicKey::from(pub_key);
-        // println!("{}", pub_key.to_jwk_string());
+        // let jwk = jose_jwk::Key::Okp(jose_jwk::Okp {
+        //     crv: jose_jwk::OkpCurves::Ed25519,
+        //     x: jose_jwk::jose_b64::serde::Bytes::from(key.verifying_key().to_bytes().to_vec()),
+        //     d: None,
+        // });
+        // println!("{}", serde_json::to_string(&jwk).unwrap());
 
-        assert_eq!(jwt, "eyJhbGciOiJFUzI1NiJ9.eyJmb28iOiJiYXIiLCJqdGkiOjIsIm5lc3RlZCI6eyJqdGkiOiJ0cmlja3kgbmVzdGluZyJ9fQ.pYf0LxoJ8sDgpmsYOgrbNecOSipnPBEGwnZzB-JhW2cONrKlqRsgXwK8_cOsyolGy-hTTe8GXbWTl_UdpF5RyA");
+        assert_eq!(jwt, "eyJhbGciOiJFZERTQSJ9.eyJmb28iOiJiYXIiLCJqdGkiOjIsIm5lc3RlZCI6eyJqdGkiOiJ0cmlja3kgbmVzdGluZyJ9fQ.Cvyc2By33KI0f0obystwdy8PN111L3Sc9_Mr2CU3XshtSqSdxuRxNEZGbb_RvyJf2IzheC_s7aBZ-jLeQ9N0Bg");
     }
 }