From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Mon, 27 Aug 2018 21:35:49 +0000 (+0200)
Subject: ixfrdist: Fix invalid buffer usage in getSerialFromMaster()
X-Git-Tag: dnsdist-1.3.3~145^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=refs%2Fpull%2F6886%2Fhead;p=thirdparty%2Fpdns.git

ixfrdist: Fix invalid buffer usage in getSerialFromMaster()
---

diff --git a/pdns/ixfrutils.cc b/pdns/ixfrutils.cc
index 180b494291..04c832451d 100644
--- a/pdns/ixfrutils.cc
+++ b/pdns/ixfrutils.cc
@@ -49,10 +49,14 @@ uint32_t getSerialFromMaster(const ComboAddress& master, const DNSName& zone, sh
   s.writen(msg);
 
   string reply;
-  char buf[4096];
+  reply.resize(4096);
   // will throw a NetworkError on timeout
-  s.readWithTimeout(buf, sizeof(buf), timeout);
-  reply.assign(buf);
+  ssize_t got = s.readWithTimeout(&reply[0], reply.size(), timeout);
+  if (got < 0 || static_cast<size_t>(got) < sizeof(dnsheader)) {
+    throw std::runtime_error("Invalid response size " + std::to_string(got));
+  }
+
+  reply.resize(got);
 
   MOADNSParser mdp(false, reply);
   if(mdp.d_header.rcode) {