From 705f87fc20d4410fd8e21986725b2063f72d864d Mon Sep 17 00:00:00 2001
From: Nicolas Frati <nicofrati@gmail.com>
Date: Mon, 18 May 2026 12:57:59 +0200
Subject: [PATCH] [management] fix: device redirect uri wasn't registered
 (#6191)

* fix: device redirect uri wasn't registered

* fix lint
---
 management/server/idp/embedded.go      | 27 ++++++++++++++++++++-----
 management/server/idp/embedded_test.go | 28 ++++++++++++++++++++++++++
 2 files changed, 50 insertions(+), 5 deletions(-)

diff --git a/management/server/idp/embedded.go b/management/server/idp/embedded.go
index a1852a8bc..821e6ff55 100644
--- a/management/server/idp/embedded.go
+++ b/management/server/idp/embedded.go
@@ -6,7 +6,9 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"net/url"
 	"os"
+	"path"
 	"strings"
 
 	"github.com/dexidp/dex/storage"
@@ -138,10 +140,13 @@ func (c *EmbeddedIdPConfig) ToYAMLConfig() (*dex.YAMLConfig, error) {
 		return nil, fmt.Errorf("invalid IdP storage config: %w", err)
 	}
 
-	// Build CLI redirect URIs including the device callback (both relative and absolute)
+	// Build CLI redirect URIs including the device callback. Dex uses the issuer-relative
+	// path (for example, /oauth2/device/callback) when completing the device flow, so
+	// include it explicitly in addition to the legacy bare path and absolute URL.
 	cliRedirectURIs := c.CLIRedirectURIs
 	cliRedirectURIs = append(cliRedirectURIs, "/device/callback")
-	cliRedirectURIs = append(cliRedirectURIs, c.Issuer+"/device/callback")
+	cliRedirectURIs = append(cliRedirectURIs, issuerRelativeDeviceCallback(c.Issuer))
+	cliRedirectURIs = append(cliRedirectURIs, strings.TrimSuffix(c.Issuer, "/")+"/device/callback")
 
 	// Build dashboard redirect URIs including the OAuth callback for proxy authentication
 	dashboardRedirectURIs := c.DashboardRedirectURIs
@@ -154,6 +159,10 @@ func (c *EmbeddedIdPConfig) ToYAMLConfig() (*dex.YAMLConfig, error) {
 	// MGMT api and the dashboard, adding baseURL means less configuration for the instance admin
 	dashboardPostLogoutRedirectURIs = append(dashboardPostLogoutRedirectURIs, baseURL)
 
+	redirectURIs := make([]string, 0)
+	redirectURIs = append(redirectURIs, cliRedirectURIs...)
+	redirectURIs = append(redirectURIs, dashboardRedirectURIs...)
+
 	cfg := &dex.YAMLConfig{
 		Issuer: c.Issuer,
 		Storage: dex.Storage{
@@ -179,14 +188,14 @@ func (c *EmbeddedIdPConfig) ToYAMLConfig() (*dex.YAMLConfig, error) {
 				ID:                     staticClientDashboard,
 				Name:                   "NetBird Dashboard",
 				Public:                 true,
-				RedirectURIs:           dashboardRedirectURIs,
+				RedirectURIs:           redirectURIs,
 				PostLogoutRedirectURIs: sanitizePostLogoutRedirectURIs(dashboardPostLogoutRedirectURIs),
 			},
 			{
 				ID:           staticClientCLI,
 				Name:         "NetBird CLI",
 				Public:       true,
-				RedirectURIs: cliRedirectURIs,
+				RedirectURIs: redirectURIs,
 			},
 		},
 		StaticConnectors: c.StaticConnectors,
@@ -217,6 +226,14 @@ func (c *EmbeddedIdPConfig) ToYAMLConfig() (*dex.YAMLConfig, error) {
 	return cfg, nil
 }
 
+func issuerRelativeDeviceCallback(issuer string) string {
+	u, err := url.Parse(issuer)
+	if err != nil || u.Path == "" {
+		return "/device/callback"
+	}
+	return path.Join(u.Path, "/device/callback")
+}
+
 // Due to how the frontend generates the logout, sometimes it appends a trailing slash
 // and because Dex only allows exact matches, we need to make sure we always have both
 // versions of each provided uri
@@ -299,7 +316,7 @@ func resolveSessionCookieEncryptionKey(configuredKey string) (string, error) {
 		}
 	}
 
-	return "", fmt.Errorf("invalid embedded IdP session cookie encryption key: %s (or sessionCookieEncryptionKey) must be 16, 24, or 32 bytes as a raw string or base64-encoded to one of those lengths; got %d raw bytes", sessionCookieEncryptionKeyEnv, len([]byte(key)))
+	return "", fmt.Errorf("invalid embedded IdP session cookie encryption key:%s (or sessionCookieEncryptionKey) must be 16, 24, or 32 bytes as a raw string or base64-encoded to one of those lengths; got %d raw bytes", sessionCookieEncryptionKeyEnv, len([]byte(key)))
 }
 
 func validSessionCookieEncryptionKeyLength(length int) bool {
diff --git a/management/server/idp/embedded_test.go b/management/server/idp/embedded_test.go
index 09dc67614..91cd27aee 100644
--- a/management/server/idp/embedded_test.go
+++ b/management/server/idp/embedded_test.go
@@ -314,6 +314,34 @@ func TestEmbeddedIdPManager_UpdateUserPassword(t *testing.T) {
 	})
 }
 
+func TestEmbeddedIdPConfig_ToYAMLConfig_IncludesDeviceCallbackRedirectURI(t *testing.T) {
+	config := &EmbeddedIdPConfig{
+		Enabled: true,
+		Issuer:  "https://example.com/oauth2",
+		Storage: EmbeddedStorageConfig{
+			Type: "sqlite3",
+			Config: EmbeddedStorageTypeConfig{
+				File: filepath.Join(t.TempDir(), "dex.db"),
+			},
+		},
+	}
+
+	yamlConfig, err := config.ToYAMLConfig()
+	require.NoError(t, err)
+
+	var cliRedirectURIs []string
+	for _, client := range yamlConfig.StaticClients {
+		if client.ID == staticClientCLI {
+			cliRedirectURIs = client.RedirectURIs
+			break
+		}
+	}
+	require.NotEmpty(t, cliRedirectURIs)
+	assert.Contains(t, cliRedirectURIs, "/device/callback")
+	assert.Contains(t, cliRedirectURIs, "/oauth2/device/callback")
+	assert.Contains(t, cliRedirectURIs, "https://example.com/oauth2/device/callback")
+}
+
 func TestEmbeddedIdPConfig_ToYAMLConfig_SessionCookieEncryptionKey(t *testing.T) {
 	t.Setenv(sessionCookieEncryptionKeyEnv, "")