From: Otto Moerbeek <otto.moerbeek@open-xchange.com>
Date: Tue, 17 Sep 2019 15:05:31 +0000 (+0200)
Subject: Fix out-of-bound access for zero length "serialized" string.
X-Git-Tag: dnsdist-1.4.0-rc3~38^2~1
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6d02e92873648cef4222d2e500ff20832989d8fe;p=pdns

Fix out-of-bound access for zero length "serialized" string.
---

diff --git a/pdns/dnsparser.cc b/pdns/dnsparser.cc
index 1f33aac27..0fd335edb 100644
--- a/pdns/dnsparser.cc
+++ b/pdns/dnsparser.cc
@@ -114,7 +114,10 @@ shared_ptr<DNSRecordContent> DNSRecordContent::unserialize(const DNSName& qname,
   drh.d_clen=htons(serialized.size());
 
   memcpy(&packet[pos], &drh, sizeof(drh)); pos+=sizeof(drh);
-  memcpy(&packet[pos], serialized.c_str(), serialized.size()); pos+=(uint16_t)serialized.size();
+  if (serialized.size() > 0) {
+    memcpy(&packet[pos], serialized.c_str(), serialized.size());
+    pos += (uint16_t) serialized.size();
+  }
 
   MOADNSParser mdp(false, (char*)&*packet.begin(), (unsigned int)packet.size());
   shared_ptr<DNSRecordContent> ret= mdp.d_answers.begin()->first.d_content;