From: Pieter Lexis <pieter.lexis@powerdns.com>
Date: Fri, 2 Oct 2015 12:21:01 +0000 (+0200)
Subject: Validate length of the zonename for NSEC3
X-Git-Tag: dnsdist-1.0.0-alpha1~230^2~33^2~3
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3155c04a99d73d0a8843ac057d1ff091cd8a9f22;p=pdns

Validate length of the zonename for NSEC3

If the zonename is too long, don't add NSEC3 semantics. Also give an
error when the zone is checked. Closes #2402.
---

diff --git a/pdns/dnsname.cc b/pdns/dnsname.cc
index 5b5567648..055b4d666 100644
--- a/pdns/dnsname.cc
+++ b/pdns/dnsname.cc
@@ -105,6 +105,15 @@ size_t DNSName::length() const {
   return this->toString().length();
 }
 
+/**
+ * Get the length of the DNSName on the wire
+ *
+ * @return the total wirelength of the DNSName
+ */
+size_t DNSName::wirelength() const {
+  return d_storage.length() + 1;
+}
+
 // are WE part of parent
 bool DNSName::isPartOf(const DNSName& parent) const
 {
diff --git a/pdns/dnsname.hh b/pdns/dnsname.hh
index bdb191433..6bf98d32a 100644
--- a/pdns/dnsname.hh
+++ b/pdns/dnsname.hh
@@ -49,6 +49,7 @@ public:
   bool isWildcard() const;
   unsigned int countLabels() const;
   size_t length() const; // FIXME400 remove me?
+  size_t wirelength() const; //!< Number of total bytes in the name
   bool empty() const { return d_empty; }
   bool isRoot() const { return !d_empty && d_storage.empty(); }
   void clear() { d_storage.clear(); d_empty=true; }
diff --git a/pdns/pdnssec.cc b/pdns/pdnssec.cc
index 8c078bb8d..7dc0c43ce 100644
--- a/pdns/pdnssec.cc
+++ b/pdns/pdnssec.cc
@@ -418,6 +418,10 @@ int checkZone(DNSSECKeeper &dk, UeberBackend &B, const DNSName& zone)
   DNSResourceRecord rr;
   uint64_t numrecords=0, numerrors=0, numwarnings=0;
 
+  if (haveNSEC3 && isSecure && zone.wirelength() > 222) {
+    numerrors++;
+    cerr<<"[Error] zone '" << zone.toStringNoDot() << "' has NSEC3 semantics but is too long to have the hash prepended. Zone name is " << zone.wirelength() << " bytes long, whereas the maximum is 222 bytes." << endl;
+  }
 
   // Check for delegation in parent zone
   DNSName parent(zone);
@@ -1729,6 +1733,10 @@ try
     NSEC3PARAMRecordContent ns3pr(nsec3params);
 
     DNSName zone(cmds[1]);
+    if (zone.wirelength() > 222) {
+      cerr<<"Cannot enable NSEC3 for " << zone.toString() << " as it is too long (" << zone.wirelength() << " bytes, maximum is 222 bytes)"<<endl;
+      return 1;
+    }
     if (! dk.setNSEC3PARAM(zone, ns3pr, narrow)) {
       cerr<<"Cannot set NSEC3 param for " << zone.toString() << endl;
       return 1;