From cc97e0d371c9427908081537d730a7dd7dc4b038 Mon Sep 17 00:00:00 2001
From: KoalaDev <6156589+Shik3i@users.noreply.github.com>
Date: Tue, 16 Jun 2026 04:21:15 +0200
Subject: [PATCH] fix(security): prevent admin token length leak via timing
 side-channel

isAdminMetricsAuthorized() returned early when buffer lengths differed,
allowing an attacker to discover the token length by measuring response
time. Now always calls crypto.timingSafeEqual (using a zeroed dummy
buffer on length mismatch) so every auth attempt takes constant time
regardless of whether the length guess was correct.

Reported-by: Kaia-Alenia
---
 server/ops.js | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/server/ops.js b/server/ops.js
index d286d3b..f956e92 100644
--- a/server/ops.js
+++ b/server/ops.js
@@ -33,8 +33,13 @@ export function isAdminMetricsAuthorized(authHeader, adminToken) {
     const expectedBuffer = Buffer.from(adminToken);
     const providedBuffer = Buffer.from(provided);
 
-    if (expectedBuffer.length !== providedBuffer.length) return false;
-    return crypto.timingSafeEqual(expectedBuffer, providedBuffer);
+    // Always run timingSafeEqual to prevent length-based timing leaks.
+    // timingSafeEqual throws on different-length buffers, so when lengths
+    // differ we compare against a zeroed buffer of the provided length
+    // (guaranteed mismatch, constant time).
+    const sameLength = expectedBuffer.length === providedBuffer.length;
+    const compareBuf = sameLength ? expectedBuffer : Buffer.alloc(providedBuffer.length);
+    return sameLength && crypto.timingSafeEqual(compareBuf, providedBuffer);
 }
 
 export function isAdminMetricsTokenStrong(adminToken, minLength = 32) {