From 40e15825f72b92f230a4133e07dd3884f8e41d37 Mon Sep 17 00:00:00 2001
From: Shreyas Zare <shreyas@technitium.com>
Date: Sat, 20 Jun 2020 16:33:19 +0530
Subject: [PATCH] ZoneTree: fixed bug in GetNextSubDomainZoneNode() which could
 cause listing of sub domains from another zone down the tree. fixed bug in
 FindNodeValue() to allow finding authority when key is for root. Fixed issue
 in FindZone() that would incorrectly report existence of sub domain.

---
 DnsServerCore/Dns/Zones/ZoneTree.cs | 45 ++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 8 deletions(-)

diff --git a/DnsServerCore/Dns/Zones/ZoneTree.cs b/DnsServerCore/Dns/Zones/ZoneTree.cs
index 0b7d3526..37ee3ec6 100644
--- a/DnsServerCore/Dns/Zones/ZoneTree.cs
+++ b/DnsServerCore/Dns/Zones/ZoneTree.cs
@@ -26,7 +26,7 @@ using TechnitiumLibrary.Net.Dns;
 
 namespace DnsServerCore.Dns.Zones
 {
-    public class ZoneTree<T> : ByteTree<string, T> where T : Zone
+    class ZoneTree<T> : ByteTree<string, T> where T : Zone
     {
         #region variables
 
@@ -202,8 +202,18 @@ namespace DnsServerCore.Dns.Zones
                             if (value != null)
                             {
                                 T zone = value.Value;
-                                if ((zone != null) && (zone is SubDomainZone))
-                                    return child; //child has value so return it
+                                if (zone != null)
+                                {
+                                    if (zone is SubDomainZone)
+                                        return child; //child has value so return it
+
+                                    if ((zone is PrimaryZone) || (zone is SecondaryZone) || (zone is StubZone) || (zone is ForwarderZone))
+                                    {
+                                        //skip to next child to avoid listing this auth zone's sub domains
+                                        child = null; //set null to avoid child being set as current after the loop
+                                        continue;
+                                    }
+                                }
                             }
 
                             if (child.Children != null)
@@ -228,7 +238,7 @@ namespace DnsServerCore.Dns.Zones
             return null;
         }
 
-        private Node GetNextSubDomainNode(Node current, int baseDepth)
+        private Node GetNextChildZoneNode(Node current, int baseDepth)
         {
             int k = 0;
 
@@ -395,7 +405,7 @@ namespace DnsServerCore.Dns.Zones
             Node wildcard = null;
             int i = 0;
 
-            while (i < key.Length)
+            while (i <= key.Length)
             {
                 //find authority zone
                 NodeValue value = closestNode.Value;
@@ -425,6 +435,9 @@ namespace DnsServerCore.Dns.Zones
                     }
                 }
 
+                if (i == key.Length)
+                    break;
+
                 Node[] children = closestNode.Children;
                 if (children == null)
                     break;
@@ -504,6 +517,22 @@ namespace DnsServerCore.Dns.Zones
             return null;
         }
 
+        private bool SubDomainExists(byte[] key, Node closestNode)
+        {
+            if (!closestNode.HasChildren)
+                return false;
+
+            Node nextSubDomain = GetNextSubDomainZoneNode(closestNode, closestNode.Depth);
+            if (nextSubDomain == null)
+                return false;
+
+            NodeValue value = nextSubDomain.Value;
+            if (value == null)
+                return false;
+
+            return IsKeySubDomain(key, value.Key);
+        }
+
         #endregion
 
         #region public
@@ -627,7 +656,7 @@ namespace DnsServerCore.Dns.Zones
                     zones.Add(ConvertKeyToLabel(GetNodeKey(current), bKey.Length));
                 }
 
-                current = GetNextSubDomainNode(current, closestNode.Depth);
+                current = GetNextChildZoneNode(current, closestNode.Depth);
             }
             while (current != null);
 
@@ -658,7 +687,7 @@ namespace DnsServerCore.Dns.Zones
                 //check if current node has sub domains
                 NodeValue value = closestNode.Value;
                 if (value == null)
-                    hasSubDomains = closestNode.HasChildren;
+                    hasSubDomains = SubDomainExists(key, closestNode);
                 else
                     hasSubDomains = IsKeySubDomain(key, value.Key);
 
@@ -692,7 +721,7 @@ namespace DnsServerCore.Dns.Zones
             else
                 authority = null;
 
-            hasSubDomains = closestNode.HasChildren;
+            hasSubDomains = SubDomainExists(key, closestNode);
             return zoneValue;
         }