update alias lookahead to respect case (#31352)

* userpass is not case sensitive
* ldap is case sensitive when it is configured that way

---------

Co-authored-by: Ben Ash <bash@hashicorp.com>

builtin/credential/ldap/backend_test.go

@@ -948,6 +948,121 @@ func TestBackend_configDefaultsAfterUpdate(t *testing.T) {
 	})
 }
 
+// TestLdapAuthBackend_AliasLookaheadDefault will test the alias lookahead functionality
+// for the LDAP auth backend with a default configuration (i.e. case insensitive if the flag is
+// not set or is set to false).
+func TestLdapAuthBackend_AliasLookaheadDefault(t *testing.T) {
+	// create config and storage
+	b, storage := createBackendWithStorage(t)
+
+	// Create user "testuser"
+	resp, err := b.HandleRequest(namespace.RootContext(nil), &logical.Request{
+		Path:      "users/testuser",
+		Operation: logical.UpdateOperation,
+		Storage:   storage,
+		Data: map[string]interface{}{
+			"policies": []string{"default"},
+			"groups":   "testgroup,nested/testgroup",
+		},
+	})
+	if err != nil || (resp != nil && resp.IsError()) {
+		t.Fatalf("bad: resp: %#v\nerr: %v", resp, err)
+	}
+
+	// List users
+	resp, err = b.HandleRequest(namespace.RootContext(nil), &logical.Request{
+		Path:      "users/",
+		Operation: logical.ListOperation,
+		Storage:   storage,
+	})
+	if err != nil || (resp != nil && resp.IsError()) {
+		t.Fatalf("bad: resp: %#v\nerr: %v", resp, err)
+	}
+	expected := []string{"testuser"}
+	if !reflect.DeepEqual(expected, resp.Data["keys"].([]string)) {
+		t.Fatalf("bad: listed users; expected: %#v actual: %#v", expected, resp.Data["keys"].([]string))
+	}
+
+	resp, err = b.HandleRequest(context.Background(), &logical.Request{
+		Operation: logical.AliasLookaheadOperation,
+		Storage:   storage,
+		Path:      "login/testuser",
+		Data: map[string]interface{}{
+			"Raw": map[string]interface{}{
+				"username": "testuser",
+			},
+		},
+	})
+	if err != nil || (resp != nil && resp.IsError()) {
+		t.Fatalf("bad: resp: %#v\nerr: %v", resp, err)
+	}
+	if resp.Auth.Alias.Name != "testuser" {
+		t.Fatalf("bad: alias lookahead did not return expected alias name; expected: 'testuser', actual: '%s'", resp.Auth.Alias.Name)
+	}
+}
+
+// TestLdapAuthBackend_AliasLookaheadCaseSensitive will test the alias lookahead functionality
+// for the LDAP auth backend when a case sensitive configuration flag is set
+func TestLdapAuthBackend_AliasLookaheadCaseSensitive(t *testing.T) {
+	// create config and storage
+	b, storage := createBackendWithStorage(t)
+
+	// make the backend case sensitive
+	resp, err := b.HandleRequest(namespace.RootContext(nil), &logical.Request{
+		Operation: logical.UpdateOperation,
+		Path:      "config",
+		Data: map[string]interface{}{
+			"case_sensitive_names": true,
+		},
+		Storage: storage,
+	})
+
+	// Create user "teSTuser"
+	resp, err = b.HandleRequest(namespace.RootContext(nil), &logical.Request{
+		Path:      "users/teSTuser",
+		Operation: logical.UpdateOperation,
+		Storage:   storage,
+		Data: map[string]interface{}{
+			"policies": []string{"default"},
+			"groups":   "testgroup,nested/testgroup",
+		},
+	})
+	if err != nil || (resp != nil && resp.IsError()) {
+		t.Fatalf("bad: resp: %#v\nerr: %v", resp, err)
+	}
+
+	// List users
+	resp, err = b.HandleRequest(namespace.RootContext(nil), &logical.Request{
+		Path:      "users/",
+		Operation: logical.ListOperation,
+		Storage:   storage,
+	})
+	if err != nil || (resp != nil && resp.IsError()) {
+		t.Fatalf("bad: resp: %#v\nerr: %v", resp, err)
+	}
+	expected := []string{"teSTuser"}
+	if !reflect.DeepEqual(expected, resp.Data["keys"].([]string)) {
+		t.Fatalf("bad: listed users; expected: %#v actual: %#v", expected, resp.Data["keys"].([]string))
+	}
+
+	resp, err = b.HandleRequest(context.Background(), &logical.Request{
+		Operation: logical.AliasLookaheadOperation,
+		Storage:   storage,
+		Path:      "login/teSTuser",
+		Data: map[string]interface{}{
+			"Raw": map[string]interface{}{
+				"username": "teSTuser",
+			},
+		},
+	})
+	if err != nil || (resp != nil && resp.IsError()) {
+		t.Fatalf("bad: resp: %#v\nerr: %v", resp, err)
+	}
+	if resp.Auth.Alias.Name != "teSTuser" {
+		t.Fatalf("bad: alias lookahead did not return expected alias name; expected: 'teSTuser', actual: '%s'", resp.Auth.Alias.Name)
+	}
+}
+
 func testAccStepConfigUrl(t *testing.T, cfg *ldaputil.ConfigEntry) logicaltest.TestStep {
 	return logicaltest.TestStep{
 		Operation: logical.UpdateOperation,

builtin/credential/ldap/path_login.go

@@ -6,6 +6,7 @@ package ldap
 import (
 	"context"
 	"fmt"
+	"strings"
 
 	"github.com/hashicorp/vault/sdk/framework"
 	"github.com/hashicorp/vault/sdk/helper/cidrutil"
@@ -50,6 +51,16 @@ func (b *backend) pathLoginAliasLookahead(ctx context.Context, req *logical.Requ
 		return nil, fmt.Errorf("missing username")
 	}
 
+	cfg, err := b.Config(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+
+	caseSensitive := cfg != nil && cfg.CaseSensitiveNames != nil && *cfg.CaseSensitiveNames
+	// if the username is not configured to be case-sensitive, we normalize it to lower case.
+	if !caseSensitive {
+		username = strings.ToLower(username)
+	}
 	return &logical.Response{
 		Auth: &logical.Auth{
 			Alias: &logical.Alias{

builtin/credential/userpass/backend_test.go

@@ -8,6 +8,7 @@ import (
 	"crypto/tls"
 	"fmt"
 	"reflect"
+	"strings"
 	"testing"
 	"time"
 
@@ -201,6 +202,35 @@ func TestBackend_userCreateOperation(t *testing.T) {
 	})
 }
 
+// TestBackend_userCreateOperationCheckCase will test the alias lookahead functionality
+// for the userpass auth method to ensure the alias returned is always lowercase due to
+// the effective case insensitivity of the auth method
+func TestBackend_userCreateOperationCheckCase(t *testing.T) {
+	b, err := Factory(context.Background(), &logical.BackendConfig{
+		Logger: nil,
+		System: &logical.StaticSystemView{
+			DefaultLeaseTTLVal: testSysTTL,
+			MaxLeaseTTLVal:     testSysMaxTTL,
+		},
+	})
+	if err != nil {
+		t.Fatalf("Unable to create backend: %s", err)
+	}
+
+	logicaltest.Test(t, logicaltest.TestCase{
+		CredentialBackend: b,
+		Steps: []logicaltest.TestStep{
+			testUserCreateOperation(t, "web", "password", "foo"),
+			testAccStepLogin(t, "web", "password", []string{"default", "foo"}),
+			testAccStepLoginAlias(t, "web", "password"),
+			testAccStepLogin(t, "WEb", "password", []string{"default", "foo"}),
+			testAccStepLoginAlias(t, "wEb", "password"),
+			testAccStepLogin(t, "WEb", "password", []string{"default", "foo"}),
+			testAccStepLoginAlias(t, "WEb", "password"),
+		},
+	})
+}
+
 func TestBackend_passwordUpdate(t *testing.T) {
 	b, err := Factory(context.Background(), &logical.BackendConfig{
 		Logger: nil,
@@ -302,6 +332,30 @@ func testAccStepLogin(t *testing.T, user string, pass string, policies []string)
 	}
 }
 
+// userpass is case insentive, so we need to ensure that the alias lookahead returns all lowercase username
+// even if the username is provided in a different case.
+func testAccStepLoginAlias(t *testing.T, user string, pass string) logicaltest.TestStep {
+	return logicaltest.TestStep{
+		Operation: logical.AliasLookaheadOperation,
+		Path:      "login/" + user,
+		Data: map[string]interface{}{
+			"Raw": map[string]interface{}{
+				"username": user,
+			},
+		},
+		Check: func(resp *logical.Response) error {
+			if resp.Auth.Alias.Name != strings.ToLower(user) {
+				return fmt.Errorf("expected alias name to be '%s', got: %s", strings.ToLower(user), resp.Auth.Alias.Name)
+			}
+			if resp.IsError() {
+				return fmt.Errorf("bad: %#v", resp)
+			}
+			return nil
+		},
+		ConnState: &tls.ConnectionState{},
+	}
+}
+
 func testUserCreateOperation(
 	t *testing.T, name string, password string, policies string,
 ) logicaltest.TestStep {

builtin/credential/userpass/path_login.go

@@ -47,10 +47,10 @@ func pathLogin(b *backend) *framework.Path {
 	}
 }
 
-func (b *backend) pathLoginAliasLookahead(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
-	username := d.Get("username").(string)
-	if username == "" {
-		return nil, fmt.Errorf("missing username")
+func (b *backend) pathLoginAliasLookahead(_ context.Context, _ *logical.Request, d *framework.FieldData) (*logical.Response, error) {
+	username, err := b.getUsername(d)
+	if err != nil {
+		return nil, err
 	}
 
 	return &logical.Response{
@@ -62,8 +62,21 @@ func (b *backend) pathLoginAliasLookahead(ctx context.Context, req *logical.Requ
 	}, nil
 }
 
+// getUsername retrieves the username from the field data, ensuring it is not
+// empty. The username is always returned in lowercase.
+func (b *backend) getUsername(d *framework.FieldData) (string, error) {
+	username := d.Get("username").(string)
+	if username == "" {
+		return "", fmt.Errorf("missing username")
+	}
+	return strings.ToLower(username), nil
+}
+
 func (b *backend) pathLogin(ctx context.Context, req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
-	username := strings.ToLower(d.Get("username").(string))
+	username, err := b.getUsername(d)
+	if err != nil {
+		return nil, err
+	}
 
 	password := d.Get("password").(string)
 	if password == "" {

changelog/31352.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+auth: update alias lookahead to respect username case for LDAP and username/password
+```