From: Richard Gibson <richard.gibson@gmail.com>
Date: Wed, 17 Oct 2018 13:25:55 +0000 (-0400)
Subject: dnsdist: Refactor overflow-unsafe comparisons
X-Git-Tag: rec-4.2.0-alpha1~16^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bf11f6f06c687a010a0c9fc489291cc86f88122f;p=thirdparty%2Fpdns.git

dnsdist: Refactor overflow-unsafe comparisons
---

diff --git a/pdns/dnsdist-lua-bindings-dnsquestion.cc b/pdns/dnsdist-lua-bindings-dnsquestion.cc
index 2c7d774169..dbbb6cdba9 100644
--- a/pdns/dnsdist-lua-bindings-dnsquestion.cc
+++ b/pdns/dnsdist-lua-bindings-dnsquestion.cc
@@ -73,7 +73,7 @@ void setupLuaBindingsDNSQuestion()
       char* message = reinterpret_cast<char*>(dq.dh);
       const uint16_t messageLen = getDNSPacketLength(message, dq.len);
       const uint16_t tailLen = tail.size();
-      if(messageLen + tailLen > dq.size) {
+      if(tailLen > (dq.size - messageLen)) {
         return false;
       }
 
@@ -154,7 +154,7 @@ void setupLuaBindingsDNSQuestion()
       char* message = reinterpret_cast<char*>(dq.dh);
       const uint16_t messageLen = getDNSPacketLength(message, dq.len);
       const uint16_t tailLen = tail.size();
-      if(messageLen + tailLen > dq.size) {
+      if(tailLen > (dq.size - messageLen)) {
         return false;
       }