Change OAuth2 expiration handling to use i64 for timestamps

src/api/admin.rs

@@ -106,7 +106,7 @@ static CAN_BACKUP: LazyLock<bool> =
 static CAN_BACKUP: LazyLock<bool> = LazyLock::new(|| false);
 
 // OAuth2 state storage for CSRF protection (state -> expiration timestamp)
-static OAUTH2_STATES: LazyLock<RwLock<HashMap<String, u64>>> = LazyLock::new(|| RwLock::new(HashMap::new()));
+static OAUTH2_STATES: LazyLock<RwLock<HashMap<String, i64>>> = LazyLock::new(|| RwLock::new(HashMap::new()));
 
 #[get("/")]
 fn admin_disabled() -> &'static str {
@@ -372,9 +372,7 @@ fn oauth2_authorize(_token: AdminToken) -> Result<Redirect, Error> {
     let state = crate::crypto::encode_random_bytes::<32>(&BASE64URL_NOPAD);
 
     // Store state with expiration (10 minutes from now)
-    // Multiple calls to Utc::now().timestamp() can return a negative value if the system time is set before the UNIX epoch.
-    // While extremely rare in practice, we handle this by using unwrap_or_default() to prevent huge values when casting to u64.
-    let now = u64::try_from(Utc::now().timestamp()).unwrap_or_default();
+    let now = Utc::now().timestamp();
     let expiration = now + 600;
 
     OAUTH2_STATES.write().unwrap().insert(state.clone(), expiration);
@@ -433,7 +431,7 @@ async fn oauth2_callback(
     // Validate state token
     let valid_state = {
         let states = OAUTH2_STATES.read().unwrap();
-        let now = u64::try_from(Utc::now().timestamp()).unwrap_or_default();
+        let now = Utc::now().timestamp();
         states.get(&state).is_some_and(|&exp| exp > now)
     };
 

src/mail.rs

@@ -31,7 +31,7 @@ use crate::http_client::make_http_request;
 pub struct OAuth2Token {
     access_token: String,
     refresh_token: Option<String>,
-    expires_at: Option<u64>,
+    expires_at: Option<i64>,
     token_type: String,
 }
 
@@ -39,7 +39,7 @@ pub struct OAuth2Token {
 struct TokenRefreshResponse {
     access_token: String,
     refresh_token: Option<String>,
-    expires_in: Option<u64>,
+    expires_in: Option<i64>,
     token_type: String,
 }
 
@@ -78,11 +78,7 @@ pub async fn refresh_oauth2_token() -> Result<OAuth2Token, Error> {
         Err(e) => err!(format!("OAuth2 Token Parse Error: {e}")),
     };
 
-    let expires_at = token_response.expires_in.map(|expires_in| {
-        // Multiple calls to Utc::now().timestamp() can return a negative value if the system time is set before the UNIX epoch.
-        // While extremely rare in practice, we handle this by using unwrap_or_default() to prevent huge values when casting to u64.
-        u64::try_from(Utc::now().timestamp()).unwrap_or_default() + expires_in
-    });
+    let expires_at = token_response.expires_in.map(|expires_in| Utc::now().timestamp() + expires_in);
 
     let new_token = OAuth2Token {
         access_token: token_response.access_token,
@@ -106,7 +102,7 @@ async fn get_valid_oauth2_token() -> Result<OAuth2Token, Error> {
         if let Some(token) = token_cache.as_ref() {
             // Check if token is still valid (with 5 min buffer)
             if let Some(expires_at) = token.expires_at {
-                let now = u64::try_from(Utc::now().timestamp()).unwrap_or_default();
+                let now = Utc::now().timestamp();
                 if now + 300 < expires_at {
                     return Ok(token.clone());
                 }
@@ -120,7 +116,7 @@ async fn get_valid_oauth2_token() -> Result<OAuth2Token, Error> {
     // Double check
     if let Some(token) = token_cache.as_ref() {
         if let Some(expires_at) = token.expires_at {
-            let now = u64::try_from(Utc::now().timestamp()).unwrap_or_default();
+            let now = Utc::now().timestamp();
             if now + 300 < expires_at {
                 return Ok(token.clone());
             }