peterzen / goresolver

DNSSEC validating resolver library

go-resolver

A Golang DNSSEC validating resolver library implemented on top of miekg/dns.

This package implements DNS lookup functions that perform DNSSEC validation.

Implementation

When querying DNSSEC enabled zones, it performs a full verification of the resource records (RRs) included in the response and validates the chain of trust:

• Requests the desired RRset (along with the corresponding RRSIG record)
• Requests the DNSKEY records containing the public ZSK and public KSK (along with the RRSIG for the DNSKEY RRset)
• Performs the cryptographic verification of the RRSIG of the requested RRset with the public ZSK
• Performs the cryptographic verification of the RRSIG of the DNSKEY RRset with the public KSK
• Checks the validity period of the RRSIG records

Following these cryptographic verifications, the package then validates the authentication chain by walking up the delegation chain, checking the public DNSKEY RRs against the DS records in each parent zone, up to the TLD zone. (For a more in-depth description of how DNSSEC works, see this guide.)

In case of any validation errors, the method returns a non-nil err value, and an empty result set.

goresolver does not yet implement denial of existence validation using NSEC or NSEC3 records.

Documentation

import "github.com/peterzen/goresolver"

result, err := resolver.StrictNSQuery("example.com.", dns.TypeMX)

if err != nil {
	// handle validation errors
}

goresolver.LookupIP can be used as drop-in replacement to net.LookupIP:

import "github.com/peterzen/goresolver"

ips, err := goresolver.LookupIP("www.example.com")

if err != nil {
	// handle validation errors
}

Installation

$ go get -u github.com/peterzen/goresolver

PRs for additional test cases covering less common DNSSEC setups are welcome and much appreciated.

More information

• DNS Security Introduction and Requirements RFC4033