refactor(authentication): authenticate merchant by API keys from API keys table (#712)

crates/router/src/core/api_keys.rs

@@ -1,10 +1,8 @@
-use common_utils::{date_time, errors::CustomResult, fp_utils};
+use common_utils::date_time;
 use error_stack::{report, IntoReport, ResultExt};
-use masking::{PeekInterface, Secret, StrongSecret};
+use masking::{PeekInterface, StrongSecret};
 use router_env::{instrument, tracing};
 
-#[cfg(feature = "kms")]
-use crate::services::kms;
 use crate::{
     configs::settings,
     consts,
@@ -14,6 +12,8 @@ use crate::{
     types::{api, storage, transformers::ForeignInto},
     utils,
 };
+#[cfg(feature = "kms")]
+use crate::{routes::metrics, services::kms};
 
 pub static HASH_KEY: tokio::sync::OnceCell<StrongSecret<[u8; PlaintextApiKey::HASH_KEY_LEN]>> =
     tokio::sync::OnceCell::const_new();
@@ -28,6 +28,10 @@ pub async fn get_hash_key(
         api_key_config.kms_encrypted_hash_key.clone(),
     )
     .await
+    .map_err(|error| {
+        metrics::AWS_KMS_FAILURES.add(&metrics::CONTEXT, 1, &[]);
+        error
+    })
     .change_context(errors::ApiErrorResponse::InternalServerError)
     .attach_printable("Failed to KMS decrypt API key hashing key")?;
 
@@ -49,11 +53,13 @@ pub async fn get_hash_key(
 
 // Defining new types `PlaintextApiKey` and `HashedApiKey` in the hopes of reducing the possibility
 // of plaintext API key being stored in the data store.
-pub struct PlaintextApiKey(Secret<String>);
+pub struct PlaintextApiKey(StrongSecret<String>);
+
+#[derive(Debug, PartialEq, Eq)]
 pub struct HashedApiKey(String);
 
 impl PlaintextApiKey {
-    pub const HASH_KEY_LEN: usize = 32;
+    const HASH_KEY_LEN: usize = 32;
 
     const PREFIX_LEN: usize = 12;
 
@@ -107,22 +113,6 @@ impl PlaintextApiKey {
                 .to_string(),
         )
     }
-
-    pub fn verify_hash(
-        &self,
-        key: &[u8; Self::HASH_KEY_LEN],
-        stored_api_key: &HashedApiKey,
-    ) -> CustomResult<(), errors::ApiKeyError> {
-        // Converting both hashes to `blake3::Hash` since it provides constant-time equality checks
-        let provided_api_key_hash = blake3::keyed_hash(key, self.0.peek().as_bytes());
-        let stored_api_key_hash = blake3::Hash::from_hex(&stored_api_key.0)
-            .into_report()
-            .change_context(errors::ApiKeyError::FailedToReadHashFromHex)?;
-
-        fp_utils::when(provided_api_key_hash != stored_api_key_hash, || {
-            Err(errors::ApiKeyError::HashVerificationFailed).into_report()
-        })
-    }
 }
 
 #[instrument(skip_all)]
@@ -165,7 +155,7 @@ pub async fn retrieve_api_key(
     key_id: &str,
 ) -> RouterResponse<api::RetrieveApiKeyResponse> {
     let api_key = store
-        .find_api_key_optional(key_id)
+        .find_api_key_by_key_id_optional(key_id)
         .await
         .change_context(errors::ApiErrorResponse::InternalServerError) // If retrieve failed
         .attach_printable("Failed to retrieve new API key")?
@@ -224,12 +214,30 @@ pub async fn list_api_keys(
     Ok(ApplicationResponse::Json(api_keys))
 }
 
+impl From<&str> for PlaintextApiKey {
+    fn from(s: &str) -> Self {
+        Self(s.to_owned().into())
+    }
+}
+
+impl From<String> for PlaintextApiKey {
+    fn from(s: String) -> Self {
+        Self(s.into())
+    }
+}
+
 impl From<HashedApiKey> for storage::HashedApiKey {
     fn from(hashed_api_key: HashedApiKey) -> Self {
         hashed_api_key.0.into()
     }
 }
 
+impl From<storage::HashedApiKey> for HashedApiKey {
+    fn from(hashed_api_key: storage::HashedApiKey) -> Self {
+        Self(hashed_api_key.into_inner())
+    }
+}
+
 #[cfg(test)]
 mod tests {
     #![allow(clippy::expect_used, clippy::unwrap_used)]
@@ -251,8 +259,7 @@ mod tests {
             hashed_api_key.0.as_bytes()
         );
 
-        plaintext_api_key
-            .verify_hash(hash_key.peek(), &hashed_api_key)
-            .unwrap();
+        let new_hashed_api_key = plaintext_api_key.keyed_hash(hash_key.peek());
+        assert_eq!(hashed_api_key, new_hashed_api_key)
     }
 }

crates/router/src/core/errors.rs

@@ -414,11 +414,3 @@ pub enum WebhooksFlowError {
     #[error("Resource not found")]
     ResourceNotFound,
 }
-
-#[derive(Debug, thiserror::Error)]
-pub enum ApiKeyError {
-    #[error("Failed to read API key hash from hexadecimal string")]
-    FailedToReadHashFromHex,
-    #[error("Failed to verify provided API key hash against stored API key hash")]
-    HashVerificationFailed,
-}

crates/router/src/db/api_keys.rs

@@ -22,11 +22,16 @@ pub trait ApiKeyInterface {
 
     async fn revoke_api_key(&self, key_id: &str) -> CustomResult<bool, errors::StorageError>;
 
-    async fn find_api_key_optional(
+    async fn find_api_key_by_key_id_optional(
         &self,
         key_id: &str,
     ) -> CustomResult<Option<storage::ApiKey>, errors::StorageError>;
 
+    async fn find_api_key_by_hash_optional(
+        &self,
+        hashed_api_key: storage::HashedApiKey,
+    ) -> CustomResult<Option<storage::ApiKey>, errors::StorageError>;
+
     async fn list_api_keys_by_merchant_id(
         &self,
         merchant_id: &str,
@@ -69,7 +74,7 @@ impl ApiKeyInterface for Store {
             .into_report()
     }
 
-    async fn find_api_key_optional(
+    async fn find_api_key_by_key_id_optional(
         &self,
         key_id: &str,
     ) -> CustomResult<Option<storage::ApiKey>, errors::StorageError> {
@@ -80,6 +85,17 @@ impl ApiKeyInterface for Store {
             .into_report()
     }
 
+    async fn find_api_key_by_hash_optional(
+        &self,
+        hashed_api_key: storage::HashedApiKey,
+    ) -> CustomResult<Option<storage::ApiKey>, errors::StorageError> {
+        let conn = pg_connection(&self.master_pool).await?;
+        storage::ApiKey::find_optional_by_hashed_api_key(&conn, hashed_api_key)
+            .await
+            .map_err(Into::into)
+            .into_report()
+    }
+
     async fn list_api_keys_by_merchant_id(
         &self,
         merchant_id: &str,
@@ -118,7 +134,7 @@ impl ApiKeyInterface for MockDb {
         Err(errors::StorageError::MockDbError)?
     }
 
-    async fn find_api_key_optional(
+    async fn find_api_key_by_key_id_optional(
         &self,
         _key_id: &str,
     ) -> CustomResult<Option<storage::ApiKey>, errors::StorageError> {
@@ -126,6 +142,14 @@ impl ApiKeyInterface for MockDb {
         Err(errors::StorageError::MockDbError)?
     }
 
+    async fn find_api_key_by_hash_optional(
+        &self,
+        _hashed_api_key: storage::HashedApiKey,
+    ) -> CustomResult<Option<storage::ApiKey>, errors::StorageError> {
+        // [#172]: Implement function for `MockDb`
+        Err(errors::StorageError::MockDbError)?
+    }
+
     async fn list_api_keys_by_merchant_id(
         &self,
         _merchant_id: &str,

crates/router/src/routes/metrics.rs

@@ -5,11 +5,12 @@ use router_env::opentelemetry::{
     Context,
 };
 
+use crate::create_counter;
+
 pub static CONTEXT: Lazy<Context> = Lazy::new(Context::current);
 static GLOBAL_METER: Lazy<Meter> = Lazy::new(|| global::meter("ROUTER_API"));
 
-pub(crate) static HEALTH_METRIC: Lazy<Counter<u64>> =
-    Lazy::new(|| GLOBAL_METER.u64_counter("HEALTH_API").init());
-
-pub(crate) static KV_MISS: Lazy<Counter<u64>> =
-    Lazy::new(|| GLOBAL_METER.u64_counter("KV_MISS").init());
+create_counter!(HEALTH_METRIC, GLOBAL_METER); // No. of health API hits
+create_counter!(KV_MISS, GLOBAL_METER); // No. of KV misses
+#[cfg(feature = "kms")]
+create_counter!(AWS_KMS_FAILURES, GLOBAL_METER); // No. of AWS KMS API failures

crates/router/src/scheduler/metrics.rs

@@ -11,6 +11,7 @@ static PT_METER: Lazy<Meter> = Lazy::new(|| global::meter("PROCESS_TRACKER"));
 pub(crate) static CONSUMER_STATS: Lazy<Histogram<f64>> =
     Lazy::new(|| PT_METER.f64_histogram("CONSUMER_OPS").init());
 
+#[macro_export]
 macro_rules! create_counter {
     ($name:ident, $meter:ident) => {
         pub(crate) static $name: Lazy<Counter<u64>> =

crates/router/src/services/authentication.rs

@@ -1,11 +1,16 @@
 use actix_web::http::header::HeaderMap;
 use api_models::{payment_methods::PaymentMethodListRequest, payments::PaymentsRequest};
 use async_trait::async_trait;
+use common_utils::date_time;
 use error_stack::{report, IntoReport, ResultExt};
 use jsonwebtoken::{decode, Algorithm, DecodingKey, Validation};
+use masking::PeekInterface;
 
 use crate::{
-    core::errors::{self, RouterResult},
+    core::{
+        api_keys,
+        errors::{self, RouterResult},
+    },
     db::StorageInterface,
     routes::{app::AppStateInfo, AppState},
     services::api,
@@ -38,11 +43,45 @@ where
         request_headers: &HeaderMap,
         state: &A,
     ) -> RouterResult<storage::MerchantAccount> {
-        let api_key =
-            get_api_key(request_headers).change_context(errors::ApiErrorResponse::Unauthorized)?;
+        let api_key = get_api_key(request_headers)
+            .change_context(errors::ApiErrorResponse::Unauthorized)?
+            .trim();
+        if api_key.is_empty() {
+            return Err(errors::ApiErrorResponse::Unauthorized)
+                .into_report()
+                .attach_printable("API key is empty");
+        }
+
+        let api_key = api_keys::PlaintextApiKey::from(api_key);
+        let hash_key = {
+            let config = state.conf();
+            api_keys::HASH_KEY
+                .get_or_try_init(|| api_keys::get_hash_key(&config.api_keys))
+                .await?
+        };
+        let hashed_api_key = api_key.keyed_hash(hash_key.peek());
+
+        let stored_api_key = state
+            .store()
+            .find_api_key_by_hash_optional(hashed_api_key.into())
+            .await
+            .change_context(errors::ApiErrorResponse::InternalServerError) // If retrieve failed
+            .attach_printable("Failed to retrieve API key")?
+            .ok_or(report!(errors::ApiErrorResponse::Unauthorized)) // If retrieve returned `None`
+            .attach_printable("Merchant not authenticated")?;
+
+        if stored_api_key
+            .expires_at
+            .map(|expires_at| expires_at < date_time::now())
+            .unwrap_or(false)
+        {
+            return Err(report!(errors::ApiErrorResponse::Unauthorized))
+                .attach_printable("API key has expired");
+        }
+
         state
             .store()
-            .find_merchant_account_by_api_key(api_key)
+            .find_merchant_account_by_merchant_id(&stored_api_key.merchant_id)
             .await
             .map_err(|e| {
                 if e.current_context().is_db_not_found() {

crates/storage_models/src/api_keys.rs

@@ -81,6 +81,12 @@ impl From<ApiKeyUpdate> for ApiKeyUpdateInternal {
 #[diesel(sql_type = diesel::sql_types::Text)]
 pub struct HashedApiKey(String);
 
+impl HashedApiKey {
+    pub fn into_inner(self) -> String {
+        self.0
+    }
+}
+
 impl From<String> for HashedApiKey {
     fn from(hashed_api_key: String) -> Self {
         Self(hashed_api_key)

crates/storage_models/src/query/api_keys.rs

@@ -3,7 +3,7 @@ use router_env::{instrument, tracing};
 
 use super::generics;
 use crate::{
-    api_keys::{ApiKey, ApiKeyNew, ApiKeyUpdate, ApiKeyUpdateInternal},
+    api_keys::{ApiKey, ApiKeyNew, ApiKeyUpdate, ApiKeyUpdateInternal, HashedApiKey},
     errors,
     schema::api_keys::dsl,
     PgPooledConn, StorageResult,
@@ -65,6 +65,18 @@ impl ApiKey {
         .await
     }
 
+    #[instrument(skip(conn))]
+    pub async fn find_optional_by_hashed_api_key(
+        conn: &PgPooledConn,
+        hashed_api_key: HashedApiKey,
+    ) -> StorageResult<Option<Self>> {
+        generics::generic_find_one_optional::<<Self as HasTable>::Table, _, _>(
+            conn,
+            dsl::hashed_api_key.eq(hashed_api_key),
+        )
+        .await
+    }
+
     #[instrument(skip(conn))]
     pub async fn find_by_merchant_id(
         conn: &PgPooledConn,