[v11.2.x] MSSQL: Correctly type UDPConnectionLimit (#99581)

MSSQL: Correctly type `UDPConnectionLimit` (#99011)

* Correctly type UDPConnectionLimit

* Update tests

* Handle legacy case

(cherry picked from commit cc09f38421)

Co-authored-by: Andreas Christou <andreas.christou@grafana.com>

pkg/tsdb/mssql/kerberos/kerberos.go

@@ -2,9 +2,11 @@ package kerberos
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
+	"strconv"
 
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana/pkg/cmd/grafana-cli/logger"
@@ -22,12 +24,37 @@ type KerberosAuth struct {
 	CredentialCache           string
 	CredentialCacheLookupFile string
 	ConfigFilePath            string
-	UDPConnectionLimit        string
+	UDPConnectionLimit        int
 	EnableDNSLookupKDC        string
 }
 
 func GetKerberosSettings(settings backend.DataSourceInstanceSettings) (kerberosAuth KerberosAuth, err error) {
+	kerberosAuth = KerberosAuth{
+		KeytabFilePath:            "",
+		CredentialCache:           "",
+		CredentialCacheLookupFile: "",
+		ConfigFilePath:            "",
+		UDPConnectionLimit:        1,
+		EnableDNSLookupKDC:        "",
+	}
+
 	err = json.Unmarshal(settings.JSONData, &kerberosAuth)
+	var unmarshalErr *json.UnmarshalTypeError
+	if err != nil && errors.As(err, &unmarshalErr) {
+		stringMap := map[string]any{}
+		err = json.Unmarshal(settings.JSONData, &stringMap)
+		if err != nil {
+			return kerberosAuth, err
+		}
+
+		if stringMap["UDPConnectionLimit"] != "" {
+			udpConnLimit, err := strconv.Atoi(stringMap["UDPConnectionLimit"].(string))
+			if err != nil {
+				return kerberosAuth, err
+			}
+			kerberosAuth.UDPConnectionLimit = udpConnLimit
+		}
+	}
 	return kerberosAuth, err
 }
 
@@ -65,8 +92,8 @@ func Krb5ParseAuthCredentials(host string, port string, db string, user string,
 		return ""
 	}
 
-	if kerberosAuth.UDPConnectionLimit != "" {
-		krb5DriverParams += "krb5-udppreferencelimit=" + kerberosAuth.UDPConnectionLimit + ";"
+	if kerberosAuth.UDPConnectionLimit != 1 {
+		krb5DriverParams += fmt.Sprintf("krb5-udppreferencelimit=%d;", kerberosAuth.UDPConnectionLimit)
 	}
 
 	if kerberosAuth.EnableDNSLookupKDC != "" {

pkg/tsdb/mssql/kerberos/kerberos_test.go

@@ -0,0 +1,63 @@
+package kerberos
+
+import (
+	"testing"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetKerberosSettings(t *testing.T) {
+	t.Run("Should correctly parse settings", func(t *testing.T) {
+		settings := backend.DataSourceInstanceSettings{
+			JSONData: []byte(`{"keytabFilePath":"keytab","credentialCache":"cache","credentialCacheLookupFile":"lookup","configFilePath":"config","UDPConnectionLimit":1,"enableDNSLookupKDC":"dns"}`),
+		}
+
+		kerberosSettings, err := GetKerberosSettings(settings)
+
+		require.NoError(t, err)
+		require.Equal(t, "keytab", kerberosSettings.KeytabFilePath)
+		require.Equal(t, "cache", kerberosSettings.CredentialCache)
+		require.Equal(t, "lookup", kerberosSettings.CredentialCacheLookupFile)
+		require.Equal(t, "config", kerberosSettings.ConfigFilePath)
+		require.Equal(t, 1, kerberosSettings.UDPConnectionLimit)
+		require.Equal(t, "dns", kerberosSettings.EnableDNSLookupKDC)
+	})
+
+	t.Run("Should correctly parse legacy UDPConnectionLimit", func(t *testing.T) {
+		settings := backend.DataSourceInstanceSettings{
+			JSONData: []byte(`{"UDPConnectionLimit":"0"}`),
+		}
+
+		kerberosSettings, err := GetKerberosSettings(settings)
+
+		require.NoError(t, err)
+		require.Equal(t, 0, kerberosSettings.UDPConnectionLimit)
+	})
+
+	t.Run("Should return defaults", func(t *testing.T) {
+		settings := backend.DataSourceInstanceSettings{
+			JSONData: []byte(`{}`),
+		}
+
+		kerberosSettings, err := GetKerberosSettings(settings)
+
+		require.NoError(t, err)
+		require.Equal(t, "", kerberosSettings.KeytabFilePath)
+		require.Equal(t, "", kerberosSettings.CredentialCache)
+		require.Equal(t, "", kerberosSettings.CredentialCacheLookupFile)
+		require.Equal(t, "", kerberosSettings.ConfigFilePath)
+		require.Equal(t, 1, kerberosSettings.UDPConnectionLimit)
+		require.Equal(t, "", kerberosSettings.EnableDNSLookupKDC)
+	})
+
+	t.Run("Will error if legacy UDPConnectionLimit can't be converted to number", func(t *testing.T) {
+		settings := backend.DataSourceInstanceSettings{
+			JSONData: []byte(`{"UDPConnectionLimit":"test"}`),
+		}
+
+		_, err := GetKerberosSettings(settings)
+
+		require.Error(t, err)
+	})
+}

pkg/tsdb/mssql/mssql_test.go

@@ -1360,8 +1360,9 @@ func TestGenerateConnectionString(t *testing.T) {
 		{
 			desc: "Use Kerberos Credential Cache",
 			kerberosCfg: kerberos.KerberosAuth{
-				CredentialCache: "/tmp/krb5cc_1000",
-				ConfigFilePath:  "/etc/krb5.conf",
+				CredentialCache:    "/tmp/krb5cc_1000",
+				ConfigFilePath:     "/etc/krb5.conf",
+				UDPConnectionLimit: 1,
 			},
 			dataSource: sqleng.DataSourceInfo{
 				URL:      "localhost",
@@ -1377,6 +1378,7 @@ func TestGenerateConnectionString(t *testing.T) {
 			kerberosCfg: kerberos.KerberosAuth{
 				CredentialCacheLookupFile: tmpFile,
 				ConfigFilePath:            "/etc/krb5.conf",
+				UDPConnectionLimit:        1,
 			},
 			dataSource: sqleng.DataSourceInfo{
 				URL:      "example.host",
@@ -1391,8 +1393,9 @@ func TestGenerateConnectionString(t *testing.T) {
 		{
 			desc: "Use Kerberos Keytab",
 			kerberosCfg: kerberos.KerberosAuth{
-				KeytabFilePath: "/foo/bar.keytab",
-				ConfigFilePath: "/etc/krb5.conf",
+				KeytabFilePath:     "/foo/bar.keytab",
+				ConfigFilePath:     "/etc/krb5.conf",
+				UDPConnectionLimit: 1,
 			},
 			dataSource: sqleng.DataSourceInfo{
 				URL:      "localhost",
@@ -1407,7 +1410,8 @@ func TestGenerateConnectionString(t *testing.T) {
 		{
 			desc: "Use Kerberos Username and Password",
 			kerberosCfg: kerberos.KerberosAuth{
-				ConfigFilePath: "/etc/krb5.conf",
+				ConfigFilePath:     "/etc/krb5.conf",
+				UDPConnectionLimit: 1,
 			},
 			dataSource: sqleng.DataSourceInfo{
 				URL:      "localhost",
@@ -1422,6 +1426,25 @@ func TestGenerateConnectionString(t *testing.T) {
 			},
 			expConnStr: "authenticator=krb5;krb5-configfile=/etc/krb5.conf;server=localhost;database=database;user id=foo@test.lab;password=foo;",
 		},
+		{
+			desc: "Use non-default UDP connection limit",
+			kerberosCfg: kerberos.KerberosAuth{
+				ConfigFilePath:     "/etc/krb5.conf",
+				UDPConnectionLimit: 0,
+			},
+			dataSource: sqleng.DataSourceInfo{
+				URL:      "localhost",
+				Database: "database",
+				User:     "foo@test.lab",
+				DecryptedSecureJSONData: map[string]string{
+					"password": "foo",
+				},
+				JsonData: sqleng.JsonData{
+					AuthenticationType: "Windows AD: Username + password",
+				},
+			},
+			expConnStr: "authenticator=krb5;krb5-configfile=/etc/krb5.conf;server=localhost;database=database;user id=foo@test.lab;password=foo;krb5-udppreferencelimit=0;",
+		},
 
 		{
 			desc: "From URL w/ port",