add user/group DNs to config

internal/auth/ldap.go

@@ -25,6 +25,8 @@ var (
 type LDAPConfig struct {
 	BindAddress       string
 	BaseDN            string
+	UserBaseDN        string
+	GroupBaseDN       string
 	TrustCertFile     string
 	DisableValidation bool
 	Insecure          bool
@@ -45,6 +47,8 @@ type LDAPIdentity struct {
 type LDAPAuthenticator struct {
 	bindAddress       string
 	baseDN            string
+	userBaseDN        string
+	groupBaseDN       string
 	trustCertFile     string
 	disableValidation bool
 	insecure          bool
@@ -54,6 +58,8 @@ type LDAPAuthenticator struct {
 func NewLDAPAuthenticator(cfg LDAPConfig) (*LDAPAuthenticator, error) {
 	bindAddress := strings.TrimSpace(cfg.BindAddress)
 	baseDN := strings.TrimSpace(cfg.BaseDN)
+	userBaseDN := strings.TrimSpace(cfg.UserBaseDN)
+	groupBaseDN := strings.TrimSpace(cfg.GroupBaseDN)
 	trustCertFile := strings.TrimSpace(cfg.TrustCertFile)
 
 	if bindAddress == "" {
@@ -62,6 +68,12 @@ func NewLDAPAuthenticator(cfg LDAPConfig) (*LDAPAuthenticator, error) {
 	if baseDN == "" {
 		return nil, fmt.Errorf("%w: base DN is required", ErrInvalidLDAPConfig)
 	}
+	if userBaseDN == "" {
+		userBaseDN = baseDN
+	}
+	if groupBaseDN == "" {
+		groupBaseDN = baseDN
+	}
 	if _, err := url.ParseRequestURI(bindAddress); err != nil {
 		return nil, fmt.Errorf("%w: bind address must be a valid URL: %v", ErrInvalidLDAPConfig, err)
 	}
@@ -74,6 +86,8 @@ func NewLDAPAuthenticator(cfg LDAPConfig) (*LDAPAuthenticator, error) {
 	return &LDAPAuthenticator{
 		bindAddress:       bindAddress,
 		baseDN:            baseDN,
+		userBaseDN:        userBaseDN,
+		groupBaseDN:       groupBaseDN,
 		trustCertFile:     trustCertFile,
 		disableValidation: cfg.DisableValidation,
 		insecure:          cfg.Insecure,
@@ -119,6 +133,10 @@ func (a *LDAPAuthenticator) AuthenticateAndFetchGroups(ctx context.Context, user
 	if rewrittenToUPN {
 		identity.Diagnostics = append(identity.Diagnostics, "bind_username_rewritten_to_upn")
 	}
+	identity.Diagnostics = append(identity.Diagnostics,
+		"user_lookup_base_dn="+a.userBaseDN,
+		"group_lookup_base_dn="+a.groupBaseDN,
+	)
 	if whoami, err := conn.WhoAmI(nil); err != nil {
 		identity.Diagnostics = append(identity.Diagnostics, fmt.Sprintf("whoami_failed:%v", err))
 	} else if boundDN := parseWhoAmIDN(whoami.AuthzID); boundDN != "" {
@@ -131,7 +149,7 @@ func (a *LDAPAuthenticator) AuthenticateAndFetchGroups(ctx context.Context, user
 	}
 
 	userLookupStartedAt := time.Now()
-	entry, lookupStrategy, err := a.lookupUserEntry(conn, bindUsername, identity.UserDN)
+	entry, lookupStrategy, err := a.lookupUserEntry(conn, inputUsername, identity.UserDN)
 	identity.UserLookupDuration = time.Since(userLookupStartedAt)
 	identity.Diagnostics = append(identity.Diagnostics, fmt.Sprintf("user_lookup_duration_ms=%d", identity.UserLookupDuration.Milliseconds()))
 	if err != nil {
@@ -329,6 +347,9 @@ func (a *LDAPAuthenticator) lookupUserEntry(conn *ldap.Conn, username string, us
 			if entry != nil {
 				return entry, "principal_upn", nil
 			}
+			// For UPN principals, avoid fallback attribute probes that are unlikely to match
+			// and can be expensive on large directory trees.
+			continue
 		}
 
 		entry, err := a.searchUserByAttribute(conn, "sAMAccountName", principal)
@@ -359,7 +380,7 @@ func (a *LDAPAuthenticator) searchUserByAttribute(conn *ldap.Conn, attribute str
 	}
 
 	searchRes, err := conn.Search(ldap.NewSearchRequest(
-		a.baseDN,
+		a.userBaseDN,
 		ldap.ScopeWholeSubtree,
 		ldap.NeverDerefAliases,
 		2,