Merge branch 'main' into profile-ownership

2026-09-25 08:09:07 +02:00 · 2026-09-24 11:49:13 +02:00
parent cfcb304fbf 507415f870
commit ec3a20e979
96 changed files with 4097 additions and 345 deletions
@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"net/http"
 	"runtime"
+	"slices"
 	"strings"
 	"sync"

@@ -26,6 +27,30 @@ var serviceCmd = &cobra.Command{

 const defaultJSONSocket = "unix:///var/run/netbird-http.sock"

+// forbiddenServiceEnvVars are the environment variables the service is never
+// registered with, keyed in upper case since these are Windows names. Each one
+// decides where the daemon resolves something it then uses with the privileges
+// of the account it runs under — LocalSystem on Windows, root elsewhere: the
+// executables it runs (PATH, PATHEXT, COMSPEC, SystemRoot, windir) or the
+// directory it writes temporary files in (TEMP, TMP). The daemon needs none of
+// them, and the utilities it shells out to are resolved by absolute path.
+var forbiddenServiceEnvVars = map[string]struct{}{
+	"PATH":       {},
+	"PATHEXT":    {},
+	"SYSTEMROOT": {},
+	"WINDIR":     {},
+	"COMSPEC":    {},
+	"TEMP":       {},
+	"TMP":        {},
+}
+
+// forbiddenServiceEnvPrefixes are the dynamic-loader families, refused whole
+// rather than by name: LD_PRELOAD, DYLD_INSERT_LIBRARIES and their siblings all
+// reach the loader of the process, the set differs per platform and libc, and
+// new members arrive with new OS releases. Listing them one by one is a list
+// that is wrong the moment it is written.
+var forbiddenServiceEnvPrefixes = []string{"LD_", "DYLD_"}
+
 var (
 	serviceName      string
 	serviceEnvVars   []string
@@ -146,8 +171,33 @@ func parseServiceEnvVars(envVars []string) (map[string]string, error) {
 			return nil, fmt.Errorf("empty environment variable key in: %s", env)
 		}

+		if isForbiddenServiceEnvVar(key) {
+			return nil, fmt.Errorf("environment variable %s cannot be set on the service: it decides where the service resolves the executables, libraries or temporary files it uses", key)
+		}
+
 		envMap[key] = value
 	}

 	return envMap, nil
 }
+
+// isForbiddenServiceEnvVar reports whether name is one the service must not be
+// registered with.
+//
+// The names are matched case-insensitively only on Windows, where they are the
+// same variable however they are spelled. Elsewhere the environment is
+// case-sensitive, so Path and PATH are two different variables and only the
+// exact spelling is the one the loader reads.
+func isForbiddenServiceEnvVar(name string) bool {
+	if runtime.GOOS == "windows" {
+		name = strings.ToUpper(name)
+	}
+
+	if _, forbidden := forbiddenServiceEnvVars[name]; forbidden {
+		return true
+	}
+
+	return slices.ContainsFunc(forbiddenServiceEnvPrefixes, func(prefix string) bool {
+		return strings.HasPrefix(name, prefix)
+	})
+}
@@ -14,6 +14,7 @@ import (

 	"github.com/netbirdio/netbird/client/configs"
 	"github.com/netbirdio/netbird/client/internal/daemonaddr"
+	"github.com/netbirdio/netbird/client/internal/elevate"
 	"github.com/netbirdio/netbird/util"
 )

@@ -50,10 +51,33 @@ func serviceParamsPath() string {

 // loadServiceParams reads saved service parameters from disk.
 // Returns nil with no error if the file does not exist.
+//
+// The file is read by an elevated install and decides the arguments and the
+// environment of the service it then registers, so it is used only when its
+// ownership and permissions are the ones saveServiceParams leaves behind. That
+// restricted ACL is applied when the file is written, which is not necessarily
+// before it is first read, so this is checked rather than assumed. A file that
+// fails the check is treated as absent, and the install proceeds with its
+// defaults.
 func loadServiceParams() (*serviceParams, error) {
 	path := serviceParamsPath()

-	data, err := os.ReadFile(path)
+	// Resolve links first so the checks apply to the file that is actually read.
+	// Since the check covers every directory above it as well, nobody who fails
+	// it can swap the file between here and the read below.
+	resolved, err := filepath.EvalSymlinks(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil //nolint:nilnil
+		}
+		return nil, fmt.Errorf("resolve service params %s: %w", path, err)
+	}
+
+	if err := elevate.CheckOnlyOwnerWritable(resolved); err != nil {
+		return nil, fmt.Errorf("refusing to read service params from %s: %w", resolved, err)
+	}
+
+	data, err := os.ReadFile(resolved)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return nil, nil //nolint:nilnil
@@ -199,10 +223,16 @@ func applyServiceParams(cmd *cobra.Command, params *serviceParams) {
 // If --service-env was explicitly set to empty, all saved env vars are cleared.
 // If --service-env was not set, saved env vars are used entirely.
 func applyServiceEnvParams(cmd *cobra.Command, params *serviceParams) {
+	// A forbidden name explicitly passed on the command line is an error the
+	// operator is told about, but one restored from a file written by an older
+	// version is dropped: an install that refuses to run would leave the host
+	// without a daemon over a variable nobody is asking for any more.
+	saved := dropForbiddenServiceEnvVars(cmd, params.ServiceEnvVars)
+
 	if !cmd.Flags().Changed("service-env") {
-		if len(params.ServiceEnvVars) > 0 {
+		if len(saved) > 0 {
 			// No explicit env vars: rebuild serviceEnvVars from saved params.
-			serviceEnvVars = envMapToSlice(params.ServiceEnvVars)
+			serviceEnvVars = envMapToSlice(saved)
 		}
 		return
 	}
@@ -221,13 +251,13 @@ func applyServiceEnvParams(cmd *cobra.Command, params *serviceParams) {
 		return
 	}

-	if len(params.ServiceEnvVars) == 0 {
+	if len(saved) == 0 {
 		return
 	}

 	// Merge saved values underneath explicit ones.
-	merged := make(map[string]string, len(params.ServiceEnvVars)+len(explicit))
-	maps.Copy(merged, params.ServiceEnvVars)
+	merged := make(map[string]string, len(saved)+len(explicit))
+	maps.Copy(merged, saved)
 	maps.Copy(merged, explicit) // explicit wins on conflict
 	serviceEnvVars = envMapToSlice(merged)
 }
@@ -250,6 +280,20 @@ var resetParamsCmd = &cobra.Command{
 	},
 }

+// dropForbiddenServiceEnvVars returns the saved entries that may still be
+// registered on the service, reporting every one it leaves behind.
+func dropForbiddenServiceEnvVars(cmd *cobra.Command, saved map[string]string) map[string]string {
+	kept := make(map[string]string, len(saved))
+	for key, value := range saved {
+		if isForbiddenServiceEnvVar(key) {
+			cmd.PrintErrf("Warning: ignoring saved service environment variable %s: it decides where the service resolves the executables, libraries or temporary files it uses\n", key)
+			continue
+		}
+		kept[key] = value
+	}
+	return kept
+}
+
 // envMapToSlice converts a map of env vars to a KEY=VALUE slice.
 func envMapToSlice(m map[string]string) []string {
 	s := make([]string, 0, len(m))
@@ -9,6 +9,7 @@ import (
 	"go/token"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 	"testing"

@@ -353,6 +354,59 @@ func TestApplyServiceEnvParams_NotChanged(t *testing.T) {
 	assert.Equal(t, map[string]string{"FROM_SAVED": "val"}, result)
 }

+func TestParseServiceEnvVars_RejectsForbiddenNames(t *testing.T) {
+	for _, env := range []string{"PATH=C:\\somewhere", "LD_PRELOAD=/tmp/lib.so", "DYLD_FALLBACK_LIBRARY_PATH=/tmp"} {
+		_, err := parseServiceEnvVars([]string{"KEEP=me", env})
+		require.Errorf(t, err, "%s selects what the service resolves and must be refused", env)
+	}
+}
+
+func TestIsForbiddenServiceEnvVar(t *testing.T) {
+	// The loader families are matched by prefix, so a name nobody has heard of
+	// yet is refused too.
+	for _, name := range []string{
+		"PATH", "PATHEXT", "COMSPEC", "SYSTEMROOT", "WINDIR", "TEMP", "TMP",
+		"LD_PRELOAD", "LD_AUDIT", "DYLD_INSERT_LIBRARIES", "DYLD_FALLBACK_FRAMEWORK_PATH",
+	} {
+		assert.Truef(t, isForbiddenServiceEnvVar(name), "%s must be refused", name)
+	}
+
+	// The prefix must not swallow names that merely start with the same letters.
+	for _, name := range []string{"NB_LOG_LEVEL", "NB_WG_DEBUG", "HTTPS_PROXY", "LDAP_URL", "DYLDX"} {
+		assert.Falsef(t, isForbiddenServiceEnvVar(name), "%s has no reason to be refused", name)
+	}
+
+	// On Windows a variable is the same one however it is spelled; elsewhere
+	// Path and PATH are two variables and only the exact one is read.
+	if runtime.GOOS == "windows" {
+		assert.True(t, isForbiddenServiceEnvVar("Path"))
+		assert.True(t, isForbiddenServiceEnvVar("ld_preload"))
+	} else {
+		assert.False(t, isForbiddenServiceEnvVar("Path"))
+		assert.False(t, isForbiddenServiceEnvVar("ld_preload"))
+	}
+}
+
+func TestApplyServiceEnvParams_DropsForbiddenSavedNames(t *testing.T) {
+	origServiceEnvVars := serviceEnvVars
+	t.Cleanup(func() { serviceEnvVars = origServiceEnvVars })
+
+	serviceEnvVars = nil
+
+	cmd := &cobra.Command{}
+	cmd.Flags().StringSlice("service-env", nil, "")
+
+	saved := &serviceParams{
+		ServiceEnvVars: map[string]string{"PATH": "C:\\attacker", "NB_LOG_FORMAT": "json"},
+	}
+
+	applyServiceEnvParams(cmd, saved)
+
+	result, err := parseServiceEnvVars(serviceEnvVars)
+	require.NoError(t, err, "a saved PATH must be dropped rather than fail the install")
+	assert.Equal(t, map[string]string{"NB_LOG_FORMAT": "json"}, result)
+}
+
 func TestApplyServiceEnvParams_ExplicitEmptyClears(t *testing.T) {
 	origServiceEnvVars := serviceEnvVars
 	t.Cleanup(func() { serviceEnvVars = origServiceEnvVars })
@@ -0,0 +1,57 @@
+//go:build !windows && !ios && !android
+
+package cmd
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/configs"
+)
+
+// The Windows equivalent of this is the ACL check in
+// elevate.CheckOnlyOwnerWritable, covered by that package's own tests; here the
+// point is that loadServiceParams asks the question at all.
+func TestLoadServiceParams_RefusesWorldWritableFile(t *testing.T) {
+	tmpDir := t.TempDir()
+
+	original := configs.StateDir
+	t.Cleanup(func() { configs.StateDir = original })
+	configs.StateDir = tmpDir
+
+	path := filepath.Join(tmpDir, serviceParamsFile)
+	require.NoError(t, os.WriteFile(path, []byte(`{"log_level":"debug"}`), 0o666))
+	// WriteFile is subject to the umask, so set the bits that matter explicitly.
+	require.NoError(t, os.Chmod(path, 0o666))
+
+	params, err := loadServiceParams()
+	require.Error(t, err, "a service.json anyone can rewrite must not be trusted")
+	assert.Nil(t, params)
+
+	require.NoError(t, os.Chmod(path, 0o600))
+	params, err = loadServiceParams()
+	require.NoError(t, err)
+	require.NotNil(t, params)
+	assert.Equal(t, "debug", params.LogLevel)
+}
+
+func TestLoadServiceParams_RefusesWorldWritableDirectory(t *testing.T) {
+	tmpDir := t.TempDir()
+	stateDir := filepath.Join(tmpDir, "state")
+	require.NoError(t, os.Mkdir(stateDir, 0o777))
+	require.NoError(t, os.Chmod(stateDir, 0o777))
+
+	original := configs.StateDir
+	t.Cleanup(func() { configs.StateDir = original })
+	configs.StateDir = stateDir
+
+	require.NoError(t, os.WriteFile(filepath.Join(stateDir, serviceParamsFile), []byte(`{}`), 0o600))
+
+	params, err := loadServiceParams()
+	require.Error(t, err, "a service.json in a directory anyone can replace entries in must not be trusted")
+	assert.Nil(t, params)
+}