rec: a single NSEC3 record covering everything is a special case

Fixes PowerDNS#13542
omoerbeek · Nov 29, 2023 · 32057b3 · 32057b3
1 parent b252c75
commit 32057b3
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/pdns/recursordist/aggressive_nsec.cc b/pdns/recursordist/aggressive_nsec.cc
@@ -229,6 +229,10 @@ static bool commonPrefixIsLong(const string& one, const string& two, size_t boun
   size_t length = 0;
   const auto minLength = std::min(one.length(), two.length());
 
+  // special case: empty zone, so the single NSEC3 covers everything. Prefix is long but we still want it cached.
+  if (one == two) {
+    return false;
+  }
   for (size_t i = 0; i < minLength; i++) {
     const auto byte1 = one.at(i);
     const auto byte2 = two.at(i);