Move Kerberos support to separate module

README.md

@@ -19,7 +19,10 @@
 * Unix socket support
 * Notifications: `LISTEN`/`NOTIFY`
 * pgpass support
-* GSS (Kerberos) auth
+
+## Optional Features
+
+* GSS (Kerberos) auth (to use, see GoDoc)
 
 ## Tests
 

auth/kerberos/go.mod

@@ -0,0 +1,8 @@
+module github.com/lib/pq/auth/kerberos
+
+go 1.13
+
+require (
+	github.com/alexbrainman/sspi v0.0.0-20180613141037-e580b900e9f5
+	github.com/jcmturner/gokrb5/v8 v8.2.0
+)

auth/kerberos/go.sum

@@ -0,0 +1,40 @@
+github.com/alexbrainman/sspi v0.0.0-20180613141037-e580b900e9f5 h1:P5U+E4x5OkVEKQDklVPmzs71WM56RTTRqV4OrDC//Y4=
+github.com/alexbrainman/sspi v0.0.0-20180613141037-e580b900e9f5/go.mod h1:976q2ETgjT2snVCf2ZaBnyBbVoPERGjUz+0sofzEfro=
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/gorilla/securecookie v1.1.1 h1:miw7JPhV+b/lAHSXz4qd/nN9jRiAFV5FwjeKyCS8BvQ=
+github.com/gorilla/securecookie v1.1.1/go.mod h1:ra0sb63/xPlUeL+yeDciTfxMRAA+MP+HVt/4epWDjd4=
+github.com/gorilla/sessions v1.2.0 h1:S7P+1Hm5V/AT9cjEcUD5uDaQSX0OE577aCXgoaKpYbQ=
+github.com/gorilla/sessions v1.2.0/go.mod h1:dk2InVEVJ0sfLlnXv9EAgkf6ecYs/i80K/zI+bUmuGM=
+github.com/hashicorp/go-uuid v1.0.2 h1:cfejS+Tpcp13yd5nYHWDI6qVCny6wyX2Mt5SGur2IGE=
+github.com/hashicorp/go-uuid v1.0.2/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
+github.com/jcmturner/aescts/v2 v2.0.0 h1:9YKLH6ey7H4eDBXW8khjYslgyqG2xZikXP0EQFKrle8=
+github.com/jcmturner/aescts/v2 v2.0.0/go.mod h1:AiaICIRyfYg35RUkr8yESTqvSy7csK90qZ5xfvvsoNs=
+github.com/jcmturner/dnsutils/v2 v2.0.0 h1:lltnkeZGL0wILNvrNiVCR6Ro5PGU/SeBvVO/8c/iPbo=
+github.com/jcmturner/dnsutils/v2 v2.0.0/go.mod h1:b0TnjGOvI/n42bZa+hmXL+kFJZsFT7G4t3HTlQ184QM=
+github.com/jcmturner/gofork v1.0.0 h1:J7uCkflzTEhUZ64xqKnkDxq3kzc96ajM1Gli5ktUem8=
+github.com/jcmturner/gofork v1.0.0/go.mod h1:MK8+TM0La+2rjBD4jE12Kj1pCCxK7d2LK/UM3ncEo0o=
+github.com/jcmturner/goidentity/v6 v6.0.1 h1:VKnZd2oEIMorCTsFBnJWbExfNN7yZr3EhJAxwOkZg6o=
+github.com/jcmturner/goidentity/v6 v6.0.1/go.mod h1:X1YW3bgtvwAXju7V3LCIMpY0Gbxyjn/mY9zx4tFonSg=
+github.com/jcmturner/gokrb5/v8 v8.2.0 h1:lzPl/30ZLkTveYsYZPKMcgXc8MbnE6RsTd4F9KgiLtk=
+github.com/jcmturner/gokrb5/v8 v8.2.0/go.mod h1:T1hnNppQsBtxW0tCHMHTkAt8n/sABdzZgZdoFrZaZNM=
+github.com/jcmturner/rpc/v2 v2.0.2 h1:gMB4IwRXYsWw4Bc6o/az2HJgFUA1ffSh90i26ZJ6Xl0=
+github.com/jcmturner/rpc/v2 v2.0.2/go.mod h1:VUJYCIDm3PVOEHw8sgt091/20OJjskO/YJki3ELg/Hc=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
+github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20200117160349-530e935923ad h1:Jh8cai0fqIK+f6nG0UgPW5wFk8wmiMhM3AyciDBdtQg=
+golang.org/x/crypto v0.0.0-20200117160349-530e935923ad/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa h1:F+8P+gmewFQYRk6JoLQLwjBCTu3mcIURZfNkVweuRKA=
+golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

auth/kerberos/krb.go

@@ -0,0 +1,29 @@
+package kerberos
+
+import (
+	"net"
+	"strings"
+)
+
+/*
+ *  Find the A record associated with a hostname
+ *  In general, hostnames supplied to the driver should be
+ *  canonicalized because the KDC usually only has one
+ *  principal and not one per potential alias of a host.
+ */
+func canonicalizeHostname(host string) (string, error) {
+	canon := host
+
+	name, err := net.LookupCNAME(host)
+	if err != nil {
+		return "", err
+	}
+
+	name = strings.TrimSuffix(name, ".")
+
+	if name != "" {
+		canon = name
+	}
+
+	return canon, nil
+}

krb_unix.go → auth/kerberos/krb_unix.go

@@ -1,6 +1,6 @@
 // +build !windows
 
-package pq
+package kerberos
 
 import (
 	"fmt"
@@ -19,13 +19,13 @@ import (
  * implementation
  */
 
-// Implements the Gss interface
-type gss struct {
+// Implements the pq.Gss interface
+type Gss struct {
 	cli *client.Client
 }
 
-func NewGSS() (Gss, error) {
-	g := &gss{}
+func NewGSS() (*Gss, error) {
+	g := &Gss{}
 	err := g.init()
 
 	if err != nil {
@@ -35,7 +35,7 @@ func NewGSS() (Gss, error) {
 	return g, nil
 }
 
-func (g *gss) init() error {
+func (g *Gss) init() error {
 	cfgPath, ok := os.LookupEnv("KRB5_CONFIG")
 	if !ok {
 		cfgPath = "/etc/krb5.conf"
@@ -75,7 +75,7 @@ func (g *gss) init() error {
 	return nil
 }
 
-func (g *gss) GetInitToken(host string, service string) ([]byte, error) {
+func (g *Gss) GetInitToken(host string, service string) ([]byte, error) {
 
 	// Resolve the hostname down to an 'A' record, if required (usually, it is)
 	if g.cli.Config.LibDefaults.DNSCanonicalizeHostname {
@@ -91,7 +91,7 @@ func (g *gss) GetInitToken(host string, service string) ([]byte, error) {
 	return g.GetInitTokenFromSpn(spn)
 }
 
-func (g *gss) GetInitTokenFromSpn(spn string) ([]byte, error) {
+func (g *Gss) GetInitTokenFromSpn(spn string) ([]byte, error) {
 	s := spnego.SPNEGOClient(g.cli, spn)
 
 	st, err := s.InitSecContext()
@@ -107,7 +107,7 @@ func (g *gss) GetInitTokenFromSpn(spn string) ([]byte, error) {
 	return b, nil
 }
 
-func (g *gss) Continue(inToken []byte) (done bool, outToken []byte, err error) {
+func (g *Gss) Continue(inToken []byte) (done bool, outToken []byte, err error) {
 	t := &spnego.SPNEGOToken{}
 	err = t.Unmarshal(inToken)
 	if err != nil {

krb_windows.go → auth/kerberos/krb_windows.go

@@ -1,19 +1,20 @@
 // +build windows
 
-package pq
+package kerberos
 
 import (
 	"github.com/alexbrainman/sspi"
 	"github.com/alexbrainman/sspi/negotiate"
 )
 
-type gss struct {
+// Implements the pq.Gss interface
+type Gss struct {
 	creds *sspi.Credentials
 	ctx   *negotiate.ClientContext
 }
 
-func NewGSS() (Gss, error) {
-	g := &gss{}
+func NewGSS() (*Gss, error) {
+	g := &Gss{}
 	err := g.init()
 
 	if err != nil {
@@ -23,7 +24,7 @@ func NewGSS() (Gss, error) {
 	return g, nil
 }
 
-func (g *gss) init() error {
+func (g *Gss) init() error {
 	creds, err := negotiate.AcquireCurrentUserCredentials()
 	if err != nil {
 		return err
@@ -33,7 +34,7 @@ func (g *gss) init() error {
 	return nil
 }
 
-func (g *gss) GetInitToken(host string, service string) ([]byte, error) {
+func (g *Gss) GetInitToken(host string, service string) ([]byte, error) {
 
 	host, err := canonicalizeHostname(host)
 	if err != nil {
@@ -45,7 +46,7 @@ func (g *gss) GetInitToken(host string, service string) ([]byte, error) {
 	return g.GetInitTokenFromSpn(spn)
 }
 
-func (g *gss) GetInitTokenFromSpn(spn string) ([]byte, error) {
+func (g *Gss) GetInitTokenFromSpn(spn string) ([]byte, error) {
 	ctx, token, err := negotiate.NewClientContext(g.creds, spn)
 	if err != nil {
 		return nil, err
@@ -56,6 +57,6 @@ func (g *gss) GetInitTokenFromSpn(spn string) ([]byte, error) {
 	return token, nil
 }
 
-func (g *gss) Continue(inToken []byte) (done bool, outToken []byte, err error) {
+func (g *Gss) Continue(inToken []byte) (done bool, outToken []byte, err error) {
 	return g.ctx.Update(inToken)
 }

conn.go

@@ -1158,7 +1158,10 @@ func (cn *conn) auth(r *readBuf, o values) {
 			errorf("unexpected authentication response: %q", t)
 		}
 	case 7: // GSSAPI, startup
-		cli, err := NewGSS()
+		if newGss == nil {
+			errorf("kerberos error: no GSSAPI provider registered (import github.com/lib/pq/auth/kerberos if you need Kerberos support)")
+		}
+		cli, err := newGss()
 		if err != nil {
 			errorf("kerberos error: %s", err.Error())
 		}

doc.go

@@ -243,5 +243,21 @@ bytes by the PostgreSQL server.
 You can find a complete, working example of Listener usage at
 https://godoc.org/github.com/lib/pq/example/listen.
 
+
+Kerberos Support
+
+
+If you need support for Kerberos authentication, add the following to your main
+package:
+
+	import "github.com/lib/pq/auth/kerberos"
+
+	func init() {
+		pq.RegisterGSSProvider(func() (pq.Gss, error) { return kerberos.NewGSS() })
+	}
+
+This package is in a separate module so that users who don't need Kerberos
+don't have to download unnecessary dependencies.
+
 */
 package pq

go.mod

@@ -1,14 +1,3 @@
 module github.com/lib/pq
 
 go 1.13
-
-require (
-	github.com/alexbrainman/sspi v0.0.0-20180613141037-e580b900e9f5 // indirect
-	github.com/jcmturner/gokrb5/v8 v8.2.0
-	golang.org/x/crypto v0.0.0-20200311171314-f7b00557c8c4 // indirect
-	gopkg.in/jcmturner/aescts.v1 v1.0.1 // indirect
-	gopkg.in/jcmturner/dnsutils.v1 v1.0.1 // indirect
-	gopkg.in/jcmturner/goidentity.v3 v3.0.0 // indirect
-	gopkg.in/jcmturner/gokrb5.v7 v7.5.0
-	gopkg.in/jcmturner/rpc.v1 v1.1.0 // indirect
-)

krb.go

@@ -1,40 +1,29 @@
 package pq
 
-import (
-	"net"
-	"strings"
-)
-
-/*
- *  Basic GSSAPI interface to abstract Windows (SSPI) from Unix
- *  APIs within the driver
- */
+// A function that creates a GSS authentication provider,
+// for use with RegisterGSSProvider.
+type NewGSSFunc func() (Gss, error)
+
+var newGss NewGSSFunc
+
+// Register the function for creating a GSS authentication provider.
+// For example, if you need to use Kerberos to authenticate with your server,
+// add this to your main package:
+//
+//	import "github.com/lib/pq/auth/kerberos"
+//	
+//	func init() {
+//		pq.RegisterGSSProvider(func() (pq.Gss, error) { return kerberos.NewGSS() })
+//	}
+func RegisterGSSProvider(newGssArg NewGSSFunc) {
+	newGss = newGssArg
+}
 
+// An interface for providing GSSAPI authentication (e.g. Kerberos).
+// You only need to care about this interface if you are writing a
+// GSS authentication provider.
 type Gss interface {
 	GetInitToken(host string, service string) ([]byte, error)
 	GetInitTokenFromSpn(spn string) ([]byte, error)
 	Continue(inToken []byte) (done bool, outToken []byte, err error)
 }
-
-/*
- *  Find the A record associated with a hostname
- *  In general, hostnames supplied to the driver should be
- *  canonicalized because the KDC usually only has one
- *  principal and not one per potential alias of a host.
- */
-func canonicalizeHostname(host string) (string, error) {
-	canon := host
-
-	name, err := net.LookupCNAME(host)
-	if err != nil {
-		return "", err
-	}
-
-	name = strings.TrimSuffix(name, ".")
-
-	if name != "" {
-		canon = name
-	}
-
-	return canon, nil
-}