From 1e8133ee3989e69bfe4b7136ae144d5b7505114a Mon Sep 17 00:00:00 2001
From: Oleg <ogrechko@top-sysops.ru>
Date: Wed, 5 Aug 2026 11:18:57 +0000
Subject: [PATCH] Request only mail/cn/displayName from LDAP instead of every
 attribute
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The real error surfaced by the previous commit's diagnostics: "Parser
error ... Encoding too long" from @ldapjs/asn1's BER decoder — a parser
desync (it misreads some later byte as a new field's length prefix),
most likely triggered while decoding some AD attribute value on one of
the ~1000 objects that we never actually use (e.g. nTSecurityDescriptor,
msDS-ReplAttributeMetaData, or similar oversized/binary attributes AD
attaches to many objects by default). Every call site only ever reads
mail/cn/displayName, so there was never a reason to request the full
attribute set — doing so avoids decoding whatever was tripping the bug,
regardless of exactly which attribute it was.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012o9j9RezxbZVKQMrB7oRLY
---
 src/lib/ldap/client.ts | 40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/src/lib/ldap/client.ts b/src/lib/ldap/client.ts
index cdeb6f1..bf08041 100644
--- a/src/lib/ldap/client.ts
+++ b/src/lib/ldap/client.ts
@@ -69,21 +69,33 @@ function search(
     // response handling, not the query itself. ldapjs runs the multi-page
     // RFC 2696 round-trips internally; callers still just see one continuous
     // stream of `searchEntry` events followed by a single `end`.
-    client.search(baseDn, { filter, scope: "sub", paged: { pageSize: 200 } }, (err, res) => {
-      if (err) {
-        reject(describeError(client, err));
-        return;
-      }
-      res.on("searchEntry", (entry) => {
-        const attributes: Record<string, string> = {};
-        for (const attr of entry.pojo.attributes) {
-          attributes[attr.type] = attr.values[0] ?? "";
+    //
+    // `attributes` is also restricted to just what callers actually read
+    // (mail/cn/displayName) instead of requesting every attribute AD has on
+    // an object. The real failure turned out to be @ldapjs/asn1's BER
+    // decoder throwing "Encoding too long" — a parser desync, most likely
+    // triggered while decoding some oversized/exotic AD attribute we never
+    // use anyway (e.g. nTSecurityDescriptor, msDS-ReplAttributeMetaData).
+    // Not requesting them sidesteps the bug entirely.
+    client.search(
+      baseDn,
+      { filter, scope: "sub", paged: { pageSize: 200 }, attributes: ["mail", "cn", "displayName"] },
+      (err, res) => {
+        if (err) {
+          reject(describeError(client, err));
+          return;
         }
-        results.push({ dn: entry.objectName ?? entry.pojo.objectName, attributes });
-      });
-      res.on("error", (searchErr) => reject(describeError(client, searchErr)));
-      res.on("end", () => resolve(results));
-    });
+        res.on("searchEntry", (entry) => {
+          const attributes: Record<string, string> = {};
+          for (const attr of entry.pojo.attributes) {
+            attributes[attr.type] = attr.values[0] ?? "";
+          }
+          results.push({ dn: entry.objectName ?? entry.pojo.objectName, attributes });
+        });
+        res.on("error", (searchErr) => reject(describeError(client, searchErr)));
+        res.on("end", () => resolve(results));
+      },
+    );
   });
 }