From b29edbeed90662e27e804977d804ad2de251af98 Mon Sep 17 00:00:00 2001
From: bert hubert <bert.hubert@netherlabs.nl>
Date: Wed, 9 Dec 2015 13:57:39 +0100
Subject: [PATCH] implement fixupCase(true) or fixupCase(false) so you can make
 your 0x20 violating code work on today's internet. Enjoy.

---
 pdns/dnsdist-lua.cc | 1 +
 pdns/dnsdist-tcp.cc | 5 +++++
 pdns/dnsdist.cc     | 7 ++++++-
 pdns/dnsdist.hh     | 1 +
 4 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/pdns/dnsdist-lua.cc b/pdns/dnsdist-lua.cc
index f50beee1e..62a45fd8d 100644
--- a/pdns/dnsdist-lua.cc
+++ b/pdns/dnsdist-lua.cc
@@ -273,6 +273,7 @@ vector<std::function<void(void)>> setupLua(bool client, const std::string& confi
     });
 
   g_lua.writeFunction("truncateTC", [](bool tc) { g_truncateTC=tc; });
+  g_lua.writeFunction("fixupCase", [](bool fu) { g_fixupCase=fu; });
 
   g_lua.registerMember("name", &ServerPolicy::name);
   g_lua.registerMember("policy", &ServerPolicy::policy);
diff --git a/pdns/dnsdist-tcp.cc b/pdns/dnsdist-tcp.cc
index 3b77395aa..77e63045b 100644
--- a/pdns/dnsdist-tcp.cc
+++ b/pdns/dnsdist-tcp.cc
@@ -366,6 +366,11 @@ void* tcpClientThread(int pipefd)
           }
         }
 
+	if(g_fixupCase) {
+	  string realname = qname.toDNSString();
+	  memcpy(response+12, realname.c_str(), realname.length());
+	}
+
         if (putNonBlockingMsgLen(ci.fd, responseLen, ds->tcpSendTimeout))
           writen2WithTimeout(ci.fd, response, responseLen, ds->tcpSendTimeout);
 
diff --git a/pdns/dnsdist.cc b/pdns/dnsdist.cc
index 3695b54c4..d8080c237 100644
--- a/pdns/dnsdist.cc
+++ b/pdns/dnsdist.cc
@@ -109,6 +109,7 @@ int g_tcpRecvTimeout{2};
 int g_tcpSendTimeout{2};
 
 bool g_truncateTC{1};
+bool g_fixupCase{0};
 static void truncateTC(const char* packet, unsigned int* len)
 try
 {
@@ -171,10 +172,14 @@ void* responderThread(std::shared_ptr<DownstreamState> state)
     else
       --state->outstanding;  // you'd think an attacker could game this, but we're using connected socket
 
+    if(g_fixupCase) {
+      string realname = ids->qname.toDNSString();
+      memcpy(packet+12, realname.c_str(), realname.length());
+    }
+
     if(dh->tc && g_truncateTC) {
       truncateTC(packet, (unsigned int*)&len);
     }
-
     uint16_t * flags = getFlagsFromDNSHeader(dh);
     uint16_t origFlags = ids->origFlags;
     /* clear the flags we are about to restore */
diff --git a/pdns/dnsdist.hh b/pdns/dnsdist.hh
index 444dc910b..115361f7c 100644
--- a/pdns/dnsdist.hh
+++ b/pdns/dnsdist.hh
@@ -398,6 +398,7 @@ extern std::vector<std::pair<ComboAddress, bool>> g_locals; // not changed at ru
 extern vector<ClientState*> g_frontends;
 extern std::string g_key; // in theory needs locking
 extern bool g_truncateTC;
+extern bool g_fixupCase;
 extern int g_tcpRecvTimeout;
 extern int g_tcpSendTimeout;
 extern uint16_t g_maxOutstanding;
-- 
2.40.0