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feat: expose more SOA fields found by dns01.FindZoneByFqdn (#980)

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This commit is contained in:
Dominik Menke 2019-10-25 00:58:50 +02:00 committed by Ludovic Fernandez
parent aab54da9a2
commit 8afde164a1
3 changed files with 155 additions and 78 deletions
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5
.golangci.toml
View file

@ -57,7 +57,10 @@
text = "`(tlsFeatureExtensionOID|ocspMustStapleFeature)` is a global variable"
[[issues.exclude-rules]]
path = "challenge/dns01/nameserver.go"
text = "`(defaultNameservers|recursiveNameservers|dnsTimeout|fqdnToZone|muFqdnToZone)` is a global variable"
text = "`(defaultNameservers|recursiveNameservers|dnsTimeout|fqdnSoaCache|muFqdnSoaCache)` is a global variable"
[[issues.exclude-rules]]
path = "challenge/dns01/nameserver_test.go"
text = "`findXByFqdnTestCases` is a global variable"
[[issues.exclude-rules]]
path = "challenge/http01/domain_matcher.go"
text = "string `Host` has \\d occurrences, make it a constant"

83
challenge/dns01/nameserver.go
View file

@ -16,8 +16,8 @@ const defaultResolvConf = "/etc/resolv.conf"
var dnsTimeout = 10 * time.Second
var (
fqdnToZone = map[string]string{}
muFqdnToZone sync.Mutex
fqdnSoaCache = map[string]*soaCacheEntry{}
muFqdnSoaCache sync.Mutex
)
var defaultNameservers = []string{
@ -28,11 +28,31 @@ var defaultNameservers = []string{
// recursiveNameservers are used to pre-check DNS propagation
var recursiveNameservers = getNameservers(defaultResolvConf, defaultNameservers)
// soaCacheEntry holds a cached SOA record (only selected fields)
type soaCacheEntry struct {
zone string // zone apex (a domain name)
primaryNs string // primary nameserver for the zone apex
expires time.Time // time when this cache entry should be evicted
}
func newSoaCacheEntry(soa *dns.SOA) *soaCacheEntry {
return &soaCacheEntry{
zone: soa.Hdr.Name,
primaryNs: soa.Ns,
expires: time.Now().Add(time.Duration(soa.Refresh) * time.Second),
}
}
// isExpired checks whether a cache entry should be considered expired.
func (cache *soaCacheEntry) isExpired() bool {
return time.Now().After(cache.expires)
}
// ClearFqdnCache clears the cache of fqdn to zone mappings. Primarily used in testing.
func ClearFqdnCache() {
muFqdnToZone.Lock()
fqdnToZone = map[string]string{}
muFqdnToZone.Unlock()
muFqdnSoaCache.Lock()
fqdnSoaCache = map[string]*soaCacheEntry{}
muFqdnSoaCache.Unlock()
}
func AddDNSTimeout(timeout time.Duration) ChallengeOption {
@ -98,6 +118,22 @@ func lookupNameservers(fqdn string) ([]string, error) {
return nil, fmt.Errorf("could not determine authoritative nameservers")
}
// FindPrimaryNsByFqdn determines the primary nameserver of the zone apex for the given fqdn
// by recursing up the domain labels until the nameserver returns a SOA record in the answer section.
func FindPrimaryNsByFqdn(fqdn string) (string, error) {
return FindPrimaryNsByFqdnCustom(fqdn, recursiveNameservers)
}
// FindPrimaryNsByFqdnCustom determines the primary nameserver of the zone apex for the given fqdn
// by recursing up the domain labels until the nameserver returns a SOA record in the answer section.
func FindPrimaryNsByFqdnCustom(fqdn string, nameservers []string) (string, error) {
soa, err := lookupSoaByFqdn(fqdn, nameservers)
if err != nil {
return "", err
}
return soa.primaryNs, nil
}
// FindZoneByFqdn determines the zone apex for the given fqdn
// by recursing up the domain labels until the nameserver returns a SOA record in the answer section.
func FindZoneByFqdn(fqdn string) (string, error) {
@ -107,14 +143,32 @@ func FindZoneByFqdn(fqdn string) (string, error) {
// FindZoneByFqdnCustom determines the zone apex for the given fqdn
// by recursing up the domain labels until the nameserver returns a SOA record in the answer section.
func FindZoneByFqdnCustom(fqdn string, nameservers []string) (string, error) {
muFqdnToZone.Lock()
defer muFqdnToZone.Unlock()
soa, err := lookupSoaByFqdn(fqdn, nameservers)
if err != nil {
return "", err
}
return soa.zone, nil
}
// Do we have it cached?
if zone, ok := fqdnToZone[fqdn]; ok {
return zone, nil
func lookupSoaByFqdn(fqdn string, nameservers []string) (*soaCacheEntry, error) {
muFqdnSoaCache.Lock()
defer muFqdnSoaCache.Unlock()
// Do we have it cached and is it still fresh?
if ent := fqdnSoaCache[fqdn]; ent != nil && !ent.isExpired() {
return ent, nil
}
ent, err := fetchSoaByFqdn(fqdn, nameservers)
if err != nil {
return nil, err
}
fqdnSoaCache[fqdn] = ent
return ent, nil
}
func fetchSoaByFqdn(fqdn string, nameservers []string) (*soaCacheEntry, error) {
var err error
var in *dns.Msg
@ -134,7 +188,6 @@ func FindZoneByFqdnCustom(fqdn string, nameservers []string) (string, error) {
switch in.Rcode {
case dns.RcodeSuccess:
// Check if we got a SOA RR in the answer section
if len(in.Answer) == 0 {
continue
}
@ -147,20 +200,18 @@ func FindZoneByFqdnCustom(fqdn string, nameservers []string) (string, error) {
for _, ans := range in.Answer {
if soa, ok := ans.(*dns.SOA); ok {
zone := soa.Hdr.Name
fqdnToZone[fqdn] = zone
return zone, nil
return newSoaCacheEntry(soa), nil
}
}
case dns.RcodeNameError:
// NXDOMAIN
default:
// Any response code other than NOERROR and NXDOMAIN is treated as error
return "", fmt.Errorf("unexpected response code '%s' for %s", dns.RcodeToString[in.Rcode], domain)
return nil, fmt.Errorf("unexpected response code '%s' for %s", dns.RcodeToString[in.Rcode], domain)
}
}
return "", fmt.Errorf("could not find the start of authority for %s%s", fqdn, formatDNSError(in, err))
return nil, fmt.Errorf("could not find the start of authority for %s%s", fqdn, formatDNSError(in, err))
}
// dnsMsgContainsCNAME checks for a CNAME answer in msg

145
challenge/dns01/nameserver_test.go
View file

@ -68,68 +68,74 @@ func TestLookupNameserversErr(t *testing.T) {
}
}
func TestFindZoneByFqdnCustom(t *testing.T) {
testCases := []struct {
desc string
fqdn string
zone string
nameservers []string
expectedError string
}{
{
desc: "domain is a CNAME",
fqdn: "mail.google.com.",
zone: "google.com.",
nameservers: recursiveNameservers,
},
{
desc: "domain is a non-existent subdomain",
fqdn: "foo.google.com.",
zone: "google.com.",
nameservers: recursiveNameservers,
},
{
desc: "domain is a eTLD",
fqdn: "example.com.ac.",
zone: "ac.",
nameservers: recursiveNameservers,
},
{
desc: "domain is a cross-zone CNAME",
fqdn: "cross-zone-example.assets.sh.",
zone: "assets.sh.",
nameservers: recursiveNameservers,
},
{
desc: "NXDOMAIN",
fqdn: "test.loho.jkl.",
zone: "loho.jkl.",
nameservers: []string{"1.1.1.1:53"},
expectedError: "could not find the start of authority for test.loho.jkl.: NXDOMAIN",
},
{
desc: "several non existent nameservers",
fqdn: "mail.google.com.",
zone: "google.com.",
nameservers: []string{":7053", ":8053", "1.1.1.1:53"},
},
{
desc: "only non existent nameservers",
fqdn: "mail.google.com.",
zone: "google.com.",
nameservers: []string{":7053", ":8053", ":9053"},
expectedError: "could not find the start of authority for mail.google.com.: read udp",
},
{
desc: "no nameservers",
fqdn: "test.ldez.com.",
zone: "ldez.com.",
nameservers: []string{},
expectedError: "could not find the start of authority for test.ldez.com.",
},
}
var findXByFqdnTestCases = []struct {
desc string
fqdn string
zone string
primaryNs string
nameservers []string
expectedError string
}{
{
desc: "domain is a CNAME",
fqdn: "mail.google.com.",
zone: "google.com.",
primaryNs: "ns1.google.com.",
nameservers: recursiveNameservers,
},
{
desc: "domain is a non-existent subdomain",
fqdn: "foo.google.com.",
zone: "google.com.",
primaryNs: "ns1.google.com.",
nameservers: recursiveNameservers,
},
{
desc: "domain is a eTLD",
fqdn: "example.com.ac.",
zone: "ac.",
primaryNs: "a0.nic.ac.",
nameservers: recursiveNameservers,
},
{
desc: "domain is a cross-zone CNAME",
fqdn: "cross-zone-example.assets.sh.",
zone: "assets.sh.",
primaryNs: "gina.ns.cloudflare.com.",
nameservers: recursiveNameservers,
},
{
desc: "NXDOMAIN",
fqdn: "test.loho.jkl.",
zone: "loho.jkl.",
nameservers: []string{"1.1.1.1:53"},
expectedError: "could not find the start of authority for test.loho.jkl.: NXDOMAIN",
},
{
desc: "several non existent nameservers",
fqdn: "mail.google.com.",
zone: "google.com.",
primaryNs: "ns1.google.com.",
nameservers: []string{":7053", ":8053", "1.1.1.1:53"},
},
{
desc: "only non existent nameservers",
fqdn: "mail.google.com.",
zone: "google.com.",
nameservers: []string{":7053", ":8053", ":9053"},
expectedError: "could not find the start of authority for mail.google.com.: read udp",
},
{
desc: "no nameservers",
fqdn: "test.ldez.com.",
zone: "ldez.com.",
nameservers: []string{},
expectedError: "could not find the start of authority for test.ldez.com.",
},
}
for _, test := range testCases {
func TestFindZoneByFqdnCustom(t *testing.T) {
for _, test := range findXByFqdnTestCases {
t.Run(test.desc, func(t *testing.T) {
ClearFqdnCache()
@ -145,6 +151,23 @@ func TestFindZoneByFqdnCustom(t *testing.T) {
}
}
func TestFindPrimayNsByFqdnCustom(t *testing.T) {
for _, test := range findXByFqdnTestCases {
t.Run(test.desc, func(t *testing.T) {
ClearFqdnCache()
ns, err := FindPrimaryNsByFqdnCustom(test.fqdn, test.nameservers)
if test.expectedError != "" {
require.Error(t, err)
assert.Contains(t, err.Error(), test.expectedError)
} else {
require.NoError(t, err)
assert.Equal(t, test.primaryNs, ns)
}
})
}
}
func TestResolveConfServers(t *testing.T) {
var testCases = []struct {
fixture string