proxy: auth broker (#8855)

Opens http2 connection to local-proxy and forwards requests over with
all headers and body

closes https://github.com/neondatabase/cloud/issues/16039

proxy/src/auth/backend.rs

@@ -565,7 +565,7 @@ mod tests {
         stream::{PqStream, Stream},
     };
 
-    use super::{auth_quirks, AuthRateLimiter};
+    use super::{auth_quirks, jwt::JwkCache, AuthRateLimiter};
 
     struct Auth {
         ips: Vec<IpPattern>,
@@ -611,12 +611,15 @@ mod tests {
     }
 
     static CONFIG: Lazy<AuthenticationConfig> = Lazy::new(|| AuthenticationConfig {
+        jwks_cache: JwkCache::default(),
         thread_pool: ThreadPool::new(1),
         scram_protocol_timeout: std::time::Duration::from_secs(5),
         rate_limiter_enabled: true,
         rate_limiter: AuthRateLimiter::new(&RateBucketInfo::DEFAULT_AUTH_SET),
         rate_limit_ip_subnet: 64,
         ip_allowlist_check_enabled: true,
+        is_auth_broker: false,
+        accept_jwts: false,
     });
 
     async fn read_message(r: &mut (impl AsyncRead + Unpin), b: &mut BytesMut) -> PgMessage {

proxy/src/auth/backend/jwt.rs

@@ -8,7 +8,7 @@ use anyhow::{bail, ensure, Context};
 use arc_swap::ArcSwapOption;
 use dashmap::DashMap;
 use jose_jwk::crypto::KeyInfo;
-use serde::{Deserialize, Deserializer};
+use serde::{de::Visitor, Deserialize, Deserializer};
 use signature::Verifier;
 use tokio::time::Instant;
 
@@ -311,13 +311,11 @@ impl JwkCacheEntryLock {
 
         tracing::debug!(?payload, "JWT signature valid with claims");
 
-        match (expected_audience, payload.audience) {
-            // check the audience matches
-            (Some(aud1), Some(aud2)) => ensure!(aud1 == aud2, "invalid JWT token audience"),
-            // the audience is expected but is missing
-            (Some(_), None) => bail!("invalid JWT token audience"),
-            // we don't care for the audience field
-            (None, _) => {}
+        if let Some(aud) = expected_audience {
+            ensure!(
+                payload.audience.0.iter().any(|s| s == aud),
+                "invalid JWT token audience"
+            );
         }
 
         let now = SystemTime::now();
@@ -420,11 +418,12 @@ struct JwtHeader<'a> {
 }
 
 /// <https://datatracker.ietf.org/doc/html/rfc7519#section-4.1>
-#[derive(serde::Deserialize, serde::Serialize, Debug)]
+#[derive(serde::Deserialize, Debug)]
+#[allow(dead_code)]
 struct JwtPayload<'a> {
     /// Audience - Recipient for which the JWT is intended
-    #[serde(rename = "aud")]
-    audience: Option<&'a str>,
+    #[serde(rename = "aud", default)]
+    audience: OneOrMany,
     /// Expiration - Time after which the JWT expires
     #[serde(deserialize_with = "numeric_date_opt", rename = "exp", default)]
     expiration: Option<SystemTime>,
@@ -447,6 +446,59 @@ struct JwtPayload<'a> {
     session_id: Option<&'a str>,
 }
 
+/// `OneOrMany` supports parsing either a single item or an array of items.
+///
+/// Needed for <https://datatracker.ietf.org/doc/html/rfc7519#section-4.1.3>
+///
+/// > The "aud" (audience) claim identifies the recipients that the JWT is
+/// > intended for.  Each principal intended to process the JWT MUST
+/// > identify itself with a value in the audience claim.  If the principal
+/// > processing the claim does not identify itself with a value in the
+/// > "aud" claim when this claim is present, then the JWT MUST be
+/// > rejected.  In the general case, the "aud" value is **an array of case-
+/// > sensitive strings**, each containing a StringOrURI value.  In the
+/// > special case when the JWT has one audience, the "aud" value MAY be a
+/// > **single case-sensitive string** containing a StringOrURI value.  The
+/// > interpretation of audience values is generally application specific.
+/// > Use of this claim is OPTIONAL.
+#[derive(Default, Debug)]
+struct OneOrMany(Vec<String>);
+
+impl<'de> Deserialize<'de> for OneOrMany {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        struct OneOrManyVisitor;
+        impl<'de> Visitor<'de> for OneOrManyVisitor {
+            type Value = OneOrMany;
+
+            fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+                formatter.write_str("a single string or an array of strings")
+            }
+
+            fn visit_str<E>(self, v: &str) -> Result<Self::Value, E>
+            where
+                E: serde::de::Error,
+            {
+                Ok(OneOrMany(vec![v.to_owned()]))
+            }
+
+            fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+            where
+                A: serde::de::SeqAccess<'de>,
+            {
+                let mut v = vec![];
+                while let Some(s) = seq.next_element()? {
+                    v.push(s);
+                }
+                Ok(OneOrMany(v))
+            }
+        }
+        deserializer.deserialize_any(OneOrManyVisitor)
+    }
+}
+
 fn numeric_date_opt<'de, D: Deserializer<'de>>(d: D) -> Result<Option<SystemTime>, D::Error> {
     let d = <Option<u64>>::deserialize(d)?;
     Ok(d.map(|n| SystemTime::UNIX_EPOCH + Duration::from_secs(n)))

proxy/src/auth/backend/local.rs

@@ -14,17 +14,15 @@ use crate::{
     EndpointId,
 };
 
-use super::jwt::{AuthRule, FetchAuthRules, JwkCache};
+use super::jwt::{AuthRule, FetchAuthRules};
 
 pub struct LocalBackend {
-    pub(crate) jwks_cache: JwkCache,
     pub(crate) node_info: NodeInfo,
 }
 
 impl LocalBackend {
     pub fn new(postgres_addr: SocketAddr) -> Self {
         LocalBackend {
-            jwks_cache: JwkCache::default(),
             node_info: NodeInfo {
                 config: {
                     let mut cfg = ConnCfg::new();