Use scram-sha-256 hash if postgresql parameter password_encryption set to do so. (zalando#995)

* Use scram-sha-256 hash if postgresql parameter password_encryption set to do so.

* test fixed

* Refactoring

* code style

Author: yanchenko-igor

go.mod

@@ -10,6 +10,7 @@ require (
 	github.com/sirupsen/logrus v1.6.0
 	github.com/stretchr/testify v1.5.1
 	golang.org/x/mod v0.3.0 // indirect
+	golang.org/x/crypto v0.0.0-20200220183623-bac4c82f6975
 	golang.org/x/tools v0.0.0-20200615222825-6aa8f57aacd9 // indirect
 	gopkg.in/yaml.v2 v2.2.8
 	k8s.io/api v0.18.3

pkg/cluster/cluster.go

@@ -124,6 +124,10 @@ func New(cfg Config, kubeClient k8sutil.KubernetesClient, pgSpec acidv1.Postgres
 
 		return fmt.Sprintf("%s-%s", e.PodName, e.ResourceVersion), nil
 	})
+	password_encryption, ok :=  pgSpec.Spec.PostgresqlParam.Parameters["password_encryption"]
+	if !ok {
+		password_encryption = "md5"
+	}
 
 	cluster := &Cluster{
 		Config:         cfg,
@@ -135,7 +139,7 @@ func New(cfg Config, kubeClient k8sutil.KubernetesClient, pgSpec acidv1.Postgres
 			Secrets:   make(map[types.UID]*v1.Secret),
 			Services:  make(map[PostgresRole]*v1.Service),
 			Endpoints: make(map[PostgresRole]*v1.Endpoints)},
-		userSyncStrategy: users.DefaultUserSyncStrategy{},
+		userSyncStrategy: users.DefaultUserSyncStrategy{password_encryption},
 		deleteOptions:    metav1.DeleteOptions{PropagationPolicy: &deletePropagationPolicy},
 		podEventsQueue:   podEventsQueue,
 		KubeClient:       kubeClient,

pkg/util/users/users.go

@@ -28,6 +28,7 @@ const (
 // an existing roles of another role membership, nor it removes the already assigned flag
 // (except for the NOLOGIN). TODO: process other NOflags, i.e. NOSUPERUSER correctly.
 type DefaultUserSyncStrategy struct {
+	PasswordEncryption string
 }
 
 // ProduceSyncRequests figures out the types of changes that need to happen with the given users.
@@ -45,7 +46,7 @@ func (strategy DefaultUserSyncStrategy) ProduceSyncRequests(dbUsers spec.PgUserM
 			}
 		} else {
 			r := spec.PgSyncUserRequest{}
-			newMD5Password := util.PGUserPassword(newUser)
+			newMD5Password := util.NewEncryptor(strategy.PasswordEncryption).PGUserPassword(newUser)
 
 			if dbUser.Password != newMD5Password {
 				r.User.Password = newMD5Password
@@ -140,7 +141,7 @@ func (strategy DefaultUserSyncStrategy) createPgUser(user spec.PgUser, db *sql.D
 	if user.Password == "" {
 		userPassword = "PASSWORD NULL"
 	} else {
-		userPassword = fmt.Sprintf(passwordTemplate, util.PGUserPassword(user))
+		userPassword = fmt.Sprintf(passwordTemplate, util.NewEncryptor(strategy.PasswordEncryption).PGUserPassword(user))
 	}
 	query := fmt.Sprintf(createUserSQL, user.Name, strings.Join(userFlags, " "), userPassword)
 
@@ -155,7 +156,7 @@ func (strategy DefaultUserSyncStrategy) alterPgUser(user spec.PgUser, db *sql.DB
 	var resultStmt []string
 
 	if user.Password != "" || len(user.Flags) > 0 {
-		alterStmt := produceAlterStmt(user)
+		alterStmt := produceAlterStmt(user, strategy.PasswordEncryption)
 		resultStmt = append(resultStmt, alterStmt)
 	}
 	if len(user.MemberOf) > 0 {
@@ -174,14 +175,14 @@ func (strategy DefaultUserSyncStrategy) alterPgUser(user spec.PgUser, db *sql.DB
 	return nil
 }
 
-func produceAlterStmt(user spec.PgUser) string {
+func produceAlterStmt(user spec.PgUser, encryption string) string {
 	// ALTER ROLE ... LOGIN ENCRYPTED PASSWORD ..
 	result := make([]string, 0)
 	password := user.Password
 	flags := user.Flags
 
 	if password != "" {
-		result = append(result, fmt.Sprintf(passwordTemplate, util.PGUserPassword(user)))
+		result = append(result, fmt.Sprintf(passwordTemplate, util.NewEncryptor(encryption).PGUserPassword(user)))
 	}
 	if len(flags) != 0 {
 		result = append(result, strings.Join(flags, " "))

pkg/util/util.go

@@ -1,8 +1,11 @@
 package util
 
 import (
+	"crypto/hmac"
 	"crypto/md5" // #nosec we need it to for PostgreSQL md5 passwords
 	cryptoRand "crypto/rand"
+	"crypto/sha256"
+	"encoding/base64"
 	"encoding/hex"
 	"fmt"
 	"math/big"
@@ -16,10 +19,14 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 
 	"github.com/zalando/postgres-operator/pkg/spec"
+	"golang.org/x/crypto/pbkdf2"
 )
 
 const (
-	md5prefix = "md5"
+	md5prefix         = "md5"
+	scramsha256prefix = "SCRAM-SHA-256"
+	saltlength        = 16
+	iterations        = 4096
 )
 
 var passwordChars = []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
@@ -61,16 +68,62 @@ func NameFromMeta(meta metav1.ObjectMeta) spec.NamespacedName {
 	}
 }
 
-// PGUserPassword is used to generate md5 password hash for a given user. It does nothing for already hashed passwords.
-func PGUserPassword(user spec.PgUser) string {
-	if (len(user.Password) == md5.Size*2+len(md5prefix) && user.Password[:3] == md5prefix) || user.Password == "" {
+type Hasher func(user spec.PgUser) string
+type Random func(n int) string
+
+type Encryptor struct {
+	encrypt Hasher
+	random  Random
+}
+
+func NewEncryptor(encryption string) *Encryptor {
+	e := Encryptor{random: RandomPassword}
+	m := map[string]Hasher{
+		"md5":           e.PGUserPasswordMD5,
+		"scram-sha-256": e.PGUserPasswordScramSHA256,
+	}
+	hasher, ok := m[encryption]
+	if !ok {
+		hasher = e.PGUserPasswordMD5
+	}
+	e.encrypt = hasher
+	return &e
+}
+
+func (e *Encryptor) PGUserPassword(user spec.PgUser) string {
+	if (len(user.Password) == md5.Size*2+len(md5prefix) && user.Password[:3] == md5prefix) ||
+		(len(user.Password) > len(scramsha256prefix) && user.Password[:len(scramsha256prefix)] == scramsha256prefix) || user.Password == "" {
 		// Avoid processing already encrypted or empty passwords
 		return user.Password
 	}
+	return e.encrypt(user)
+}
+
+func (e *Encryptor) PGUserPasswordMD5(user spec.PgUser) string {
 	s := md5.Sum([]byte(user.Password + user.Name)) // #nosec, using md5 since PostgreSQL uses it for hashing passwords.
 	return md5prefix + hex.EncodeToString(s[:])
 }
 
+func (e *Encryptor) PGUserPasswordScramSHA256(user spec.PgUser) string {
+	salt := []byte(e.random(saltlength))
+	key := pbkdf2.Key([]byte(user.Password), salt, iterations, 32, sha256.New)
+	mac := hmac.New(sha256.New, key)
+	mac.Write([]byte("Server Key"))
+	serverKey := mac.Sum(nil)
+	mac = hmac.New(sha256.New, key)
+	mac.Write([]byte("Client Key"))
+	clientKey := mac.Sum(nil)
+	storedKey := sha256.Sum256(clientKey)
+	pass := fmt.Sprintf("%s$%v:%s$%s:%s",
+		scramsha256prefix,
+		iterations,
+		base64.StdEncoding.EncodeToString(salt),
+		base64.StdEncoding.EncodeToString(storedKey[:]),
+		base64.StdEncoding.EncodeToString(serverKey),
+	)
+	return pass
+}
+
 // Diff returns diffs between 2 objects
 func Diff(a, b interface{}) []string {
 	return pretty.Diff(a, b)

pkg/util/util_test.go

@@ -12,20 +12,27 @@ import (
 )
 
 var pgUsers = []struct {
-	in  spec.PgUser
-	out string
+	in             spec.PgUser
+	outmd5         string
+	outscramsha256 string
 }{{spec.PgUser{
 	Name:     "test",
 	Password: "password",
 	Flags:    []string{},
 	MemberOf: []string{}},
-	"md587f77988ccb5aa917c93201ba314fcd4"},
+	"md587f77988ccb5aa917c93201ba314fcd4", "SCRAM-SHA-256$4096:c2FsdA==$lF4cRm/Jky763CN4HtxdHnjV4Q8AWTNlKvGmEFFU8IQ=:ub8OgRsftnk2ccDMOt7ffHXNcikRkQkq1lh4xaAqrSw="},
 	{spec.PgUser{
 		Name:     "test",
 		Password: "md592f413f3974bdf3799bb6fecb5f9f2c6",
 		Flags:    []string{},
 		MemberOf: []string{}},
-		"md592f413f3974bdf3799bb6fecb5f9f2c6"}}
+		"md592f413f3974bdf3799bb6fecb5f9f2c6", "md592f413f3974bdf3799bb6fecb5f9f2c6"},
+	{spec.PgUser{
+		Name:     "test",
+		Password: "SCRAM-SHA-256$4096:S1ByZWhvYVV5VDlJNGZoVw==$ozLevu5k0pAQYRrSY+vZhetO6+/oB+qZvuutOdXR94U=:yADwhy0LGloXzh5RaVwLMFyUokwI17VkHVfKVuHu0Zs=",
+		Flags:    []string{},
+		MemberOf: []string{}},
+		"SCRAM-SHA-256$4096:S1ByZWhvYVV5VDlJNGZoVw==$ozLevu5k0pAQYRrSY+vZhetO6+/oB+qZvuutOdXR94U=:yADwhy0LGloXzh5RaVwLMFyUokwI17VkHVfKVuHu0Zs=", "SCRAM-SHA-256$4096:S1ByZWhvYVV5VDlJNGZoVw==$ozLevu5k0pAQYRrSY+vZhetO6+/oB+qZvuutOdXR94U=:yADwhy0LGloXzh5RaVwLMFyUokwI17VkHVfKVuHu0Zs="}}
 
 var prettyDiffTest = []struct {
 	inA interface{}
@@ -107,9 +114,16 @@ func TestNameFromMeta(t *testing.T) {
 
 func TestPGUserPassword(t *testing.T) {
 	for _, tt := range pgUsers {
-		pwd := PGUserPassword(tt.in)
-		if pwd != tt.out {
-			t.Errorf("PgUserPassword expected: %q, got: %q", tt.out, pwd)
+		e := NewEncryptor("md5")
+		pwd := e.PGUserPassword(tt.in)
+		if pwd != tt.outmd5 {
+			t.Errorf("PgUserPassword expected: %q, got: %q", tt.outmd5, pwd)
+		}
+		e = NewEncryptor("scram-sha-256")
+		e.random = func(n int) string { return "salt" }
+		pwd = e.PGUserPassword(tt.in)
+		if pwd != tt.outscramsha256 {
+			t.Errorf("PgUserPassword expected: %q, got: %q", tt.outscramsha256, pwd)
 		}
 	}
 }