Support Kubernetes basic-auth secrets

Co-authored-by: Romain <rtribotte@users.noreply.github.com>

docs/content/middlewares/http/basicauth.md

@@ -88,6 +88,13 @@ The `users` option is an array of authorized users. Each user must be declared u
     - If both `users` and `usersFile` are provided, the two are merged. The contents of `usersFile` have precedence over the values in `users`.
     - For security reasons, the field `users` doesn't exist for Kubernetes IngressRoute, and one should use the `secret` field instead.
 
+!!! note "Kubernetes kubernetes.io/basic-auth secret type"
+    
+    Kubernetes supports a special `kubernetes.io/basic-auth` secret type.
+    This secret must contain two keys: `username` and `password`.
+    Please note that these keys are not hashed or encrypted in any way, and therefore is less secure than other methods.
+    You can find more information on the [Kubernetes Basic Authentication Secret Documentation](https://kubernetes.io/docs/concepts/configuration/secret/#basic-authentication-secret)
+
 ```yaml tab="Docker"
 # Declaring the user list
 #
@@ -118,11 +125,24 @@ kind: Secret
 metadata:
   name: authsecret
   namespace: default
-
 data:
   users: |2
     dGVzdDokYXByMSRINnVza2trVyRJZ1hMUDZld1RyU3VCa1RycUU4d2ovCnRlc3QyOiRhcHIxJGQ5
     aHI5SEJCJDRIeHdnVWlyM0hQNEVzZ2dQL1FObzAK
+
+---
+# This is an alternate auth secret that demonstrates the basic-auth secret type.
+# Note: the password is not hashed, and is merely base64 encoded.
+
+apiVersion: v1
+kind: Secret
+metadata:
+  name: authsecret2
+  namespace: default
+type: kubernetes.io/basic-auth
+data:
+  username: dXNlcg== # username: user
+  password: cGFzc3dvcmQ= # password: password
 ```
 
 ```yaml tab="Consul Catalog"

pkg/provider/kubernetes/crd/fixtures/basic_auth_secrets.yml

@@ -0,0 +1,23 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: basic-auth-secret
+  namespace: default
+type: kubernetes.io/basic-auth
+data:
+  username: dXNlcg== # username: user
+  password: cGFzc3dvcmQ= # password: password
+
+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: auth-secret
+  namespace: default
+
+data:
+  # test:test -> test:$apr1$H6uskkkW$IgXLP6ewTrSuBkTrqE8wj/
+  # test2:test2 -> test2:$apr1$d9hr9HBB$4HxwgUir3HP4EsggP/QNo0
+  users: |2
+    dGVzdDokYXByMSRINnVza2trVyRJZ1hMUDZld1RyU3VCa1RycUU4d2ovCnRlc3QyOiRhcHIxJGQ5
+    aHI5SEJCJDRIeHdnVWlyM0hQNEVzZ2dQL1FObzAK

pkg/provider/kubernetes/crd/kubernetes.go

@@ -4,7 +4,9 @@ import (
 	"bufio"
 	"bytes"
 	"context"
+	"crypto/sha1"
 	"crypto/sha256"
+	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -555,9 +557,38 @@ func createBasicAuthMiddleware(client Client, namespace string, basicAuth *v1alp
 		return nil, nil
 	}
 
-	credentials, err := getAuthCredentials(client, basicAuth.Secret, namespace)
+	if basicAuth.Secret == "" {
+		return nil, fmt.Errorf("auth secret must be set")
+	}
+
+	secret, ok, err := client.GetSecret(namespace, basicAuth.Secret)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to fetch secret '%s/%s': %w", namespace, basicAuth.Secret, err)
+	}
+	if !ok {
+		return nil, fmt.Errorf("secret '%s/%s' not found", namespace, basicAuth.Secret)
+	}
+	if secret == nil {
+		return nil, fmt.Errorf("data for secret '%s/%s' must not be nil", namespace, basicAuth.Secret)
+	}
+
+	if secret.Type == corev1.SecretTypeBasicAuth {
+		credentials, err := loadBasicAuthCredentials(secret)
+		if err != nil {
+			return nil, fmt.Errorf("failed to load basic auth credentials: %w", err)
+		}
+
+		return &dynamic.BasicAuth{
+			Users:        credentials,
+			Realm:        basicAuth.Realm,
+			RemoveHeader: basicAuth.RemoveHeader,
+			HeaderField:  basicAuth.HeaderField,
+		}, nil
+	}
+
+	credentials, err := loadAuthCredentials(secret)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load basic auth credentials: %w", err)
 	}
 
 	return &dynamic.BasicAuth{
@@ -573,9 +604,24 @@ func createDigestAuthMiddleware(client Client, namespace string, digestAuth *v1a
 		return nil, nil
 	}
 
-	credentials, err := getAuthCredentials(client, digestAuth.Secret, namespace)
+	if digestAuth.Secret == "" {
+		return nil, fmt.Errorf("auth secret must be set")
+	}
+
+	secret, ok, err := client.GetSecret(namespace, digestAuth.Secret)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("failed to fetch secret '%s/%s': %w", namespace, digestAuth.Secret, err)
+	}
+	if !ok {
+		return nil, fmt.Errorf("secret '%s/%s' not found", namespace, digestAuth.Secret)
+	}
+	if secret == nil {
+		return nil, fmt.Errorf("data for secret '%s/%s' must not be nil", namespace, digestAuth.Secret)
+	}
+
+	credentials, err := loadAuthCredentials(secret)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load digest auth credentials: %w", err)
 	}
 
 	return &dynamic.DigestAuth{
@@ -586,32 +632,23 @@ func createDigestAuthMiddleware(client Client, namespace string, digestAuth *v1a
 	}, nil
 }
 
-func getAuthCredentials(k8sClient Client, authSecret, namespace string) ([]string, error) {
-	if authSecret == "" {
-		return nil, fmt.Errorf("auth secret must be set")
+func loadBasicAuthCredentials(secret *corev1.Secret) ([]string, error) {
+	username, usernameExists := secret.Data["username"]
+	password, passwordExists := secret.Data["password"]
+	if !(usernameExists && passwordExists) {
+		return nil, fmt.Errorf("secret '%s/%s' must contain both username and password keys", secret.Namespace, secret.Name)
 	}
 
-	auth, err := loadAuthCredentials(namespace, authSecret, k8sClient)
-	if err != nil {
-		return nil, fmt.Errorf("failed to load auth credentials: %w", err)
-	}
+	hash := sha1.New()
+	hash.Write(password)
+	passwordSum := base64.StdEncoding.EncodeToString(hash.Sum(nil))
 
-	return auth, nil
+	return []string{fmt.Sprintf("%s:{SHA}%s", username, passwordSum)}, nil
 }
 
-func loadAuthCredentials(namespace, secretName string, k8sClient Client) ([]string, error) {
-	secret, ok, err := k8sClient.GetSecret(namespace, secretName)
-	if err != nil {
-		return nil, fmt.Errorf("failed to fetch secret '%s/%s': %w", namespace, secretName, err)
-	}
-	if !ok {
-		return nil, fmt.Errorf("secret '%s/%s' not found", namespace, secretName)
-	}
-	if secret == nil {
-		return nil, fmt.Errorf("data for secret '%s/%s' must not be nil", namespace, secretName)
-	}
+func loadAuthCredentials(secret *corev1.Secret) ([]string, error) {
 	if len(secret.Data) != 1 {
-		return nil, fmt.Errorf("found %d elements for secret '%s/%s', must be single element exactly", len(secret.Data), namespace, secretName)
+		return nil, fmt.Errorf("found %d elements for secret '%s/%s', must be single element exactly", len(secret.Data), secret.Namespace, secret.Name)
 	}
 
 	var firstSecret []byte
@@ -628,10 +665,10 @@ func loadAuthCredentials(namespace, secretName string, k8sClient Client) ([]stri
 		}
 	}
 	if err := scanner.Err(); err != nil {
-		return nil, fmt.Errorf("error reading secret for %s/%s: %w", namespace, secretName, err)
+		return nil, fmt.Errorf("error reading secret for %s/%s: %w", secret.Namespace, secret.Name, err)
 	}
 	if len(credentials) == 0 {
-		return nil, fmt.Errorf("secret '%s/%s' does not contain any credentials", namespace, secretName)
+		return nil, fmt.Errorf("secret '%s/%s' does not contain any credentials", secret.Namespace, secret.Name)
 	}
 
 	return credentials, nil

pkg/provider/kubernetes/crd/kubernetes_test.go

@@ -4,9 +4,11 @@ import (
 	"context"
 	"os"
 	"path/filepath"
+	"strings"
 	"testing"
 	"time"
 
+	auth "github.com/abbot/go-http-auth"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/traefik/paerser/types"
@@ -5265,3 +5267,66 @@ func TestExternalNameService(t *testing.T) {
 		})
 	}
 }
+
+func TestCreateBasicAuthCredentials(t *testing.T) {
+	var k8sObjects []runtime.Object
+	var crdObjects []runtime.Object
+	yamlContent, err := os.ReadFile(filepath.FromSlash("./fixtures/basic_auth_secrets.yml"))
+	if err != nil {
+		panic(err)
+	}
+
+	objects := k8s.MustParseYaml(yamlContent)
+	for _, obj := range objects {
+		switch o := obj.(type) {
+		case *corev1.Secret:
+			k8sObjects = append(k8sObjects, o)
+		default:
+		}
+	}
+
+	kubeClient := kubefake.NewSimpleClientset(k8sObjects...)
+	crdClient := crdfake.NewSimpleClientset(crdObjects...)
+
+	client := newClientImpl(kubeClient, crdClient)
+
+	stopCh := make(chan struct{})
+
+	eventCh, err := client.WatchAll([]string{"default"}, stopCh)
+	require.NoError(t, err)
+
+	if k8sObjects != nil || crdObjects != nil {
+		// just wait for the first event
+		<-eventCh
+	}
+
+	// Testing for username/password components in basic-auth secret
+	basicAuth, secretErr := createBasicAuthMiddleware(client, "default", &v1alpha1.BasicAuth{Secret: "basic-auth-secret"})
+	require.NoError(t, secretErr)
+	require.Len(t, basicAuth.Users, 1)
+
+	components := strings.Split(basicAuth.Users[0], ":")
+	require.Len(t, components, 2)
+
+	username := components[0]
+	hashedPassword := components[1]
+
+	require.Equal(t, "user", username)
+	require.Equal(t, "{SHA}W6ph5Mm5Pz8GgiULbPgzG37mj9g=", hashedPassword)
+	assert.True(t, auth.CheckSecret("password", hashedPassword))
+
+	// Testing for username/password components in htpasswd secret
+	basicAuth, secretErr = createBasicAuthMiddleware(client, "default", &v1alpha1.BasicAuth{Secret: "auth-secret"})
+	require.NoError(t, secretErr)
+	require.Len(t, basicAuth.Users, 2)
+
+	components = strings.Split(basicAuth.Users[1], ":")
+	require.Len(t, components, 2)
+
+	username = components[0]
+	hashedPassword = components[1]
+
+	assert.Equal(t, username, "test2")
+	assert.Equal(t, hashedPassword, "$apr1$d9hr9HBB$4HxwgUir3HP4EsggP/QNo0")
+	assert.True(t, auth.CheckSecret("test2", hashedPassword))
+}