Merge branch 'main' into embedded-vnc

client/ui/services/guarded.go

@@ -0,0 +1,235 @@
+//go:build !android && !ios && !freebsd && !js
+
+package services
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+
+	"github.com/netbirdio/netbird/client/internal/elevate"
+	"github.com/netbirdio/netbird/client/internal/ipcauth"
+)
+
+// The command line of the one-shot mode this binary runs itself in, elevated, to
+// apply a setting the daemon restricts to root/administrator. The setting flags
+// spell the same words as `netbird up`, so the command a user is shown and what
+// runs behind the prompt read alike. Parsed in oneshot.go.
+const (
+	FlagApplyPrivilegedSettings = "apply-privileged-settings"
+	FlagDaemonAddr              = "daemon-addr"
+	FlagProfile                 = "profile"
+	FlagUser                    = "user"
+	FlagLogLevel                = "log-level"
+	FlagManagementURL           = "management-url"
+	FlagAllowServerSSH          = "allow-server-ssh"
+	FlagEnableSSHRoot           = "enable-ssh-root"
+	FlagDisableSSHAuth          = "disable-ssh-auth"
+	FlagAllowServerVNC          = "allow-server-vnc"
+	FlagDisableVNCApproval      = "disable-vnc-approval"
+)
+
+// Error codes for the ways asking for privileges can fail.
+const (
+	CodeElevationUnavailable = "elevation_unavailable"
+	CodeElevationFailed      = "elevation_failed"
+)
+
+// elevationTimeout bounds the wait for a prompt and the change behind it, so a
+// dialog nobody answers does not leave its control disabled for the session. Long
+// enough to find a password manager, and no shorter than the platforms' own prompt
+// timeouts: Windows gives up on its consent dialog after two minutes by itself.
+//
+// It always ends our waiting, and not always the prompt: Security.framework offers
+// no way to withdraw a request, so on macOS the system's own timeout is what closes
+// the dialog.
+const elevationTimeout = 5 * time.Minute
+
+// elevator raises the platform's privilege prompt and runs the change behind it.
+// An interface so tests can answer without a prompt.
+type elevator interface {
+	// Run runs this binary again, elevated, with the given arguments.
+	Run(ctx context.Context, args ...string) error
+	// Available reports whether there is a prompt to raise on this host at all.
+	Available() bool
+}
+
+// osElevator is the real thing: see the elevate package.
+type osElevator struct{}
+
+func (osElevator) Run(ctx context.Context, args ...string) error {
+	return elevate.Run(ctx, args...)
+}
+
+func (osElevator) Available() bool {
+	return elevate.Available()
+}
+
+// SaveOutcome reports what became of a change that needed authorization.
+//
+// A declined prompt is a result, not an error: the user was asked and said no, so
+// nothing was applied and nothing went wrong. Reporting it as an error would have
+// every cancelled prompt logged as one.
+type SaveOutcome struct {
+	// Declined is set when the user dismissed the authorization prompt, or was
+	// refused by policy. Nothing was changed.
+	Declined bool `json:"declined"`
+}
+
+// GuardedSettings is the subset of the config the daemon restricts to
+// root/administrator. Only the fields that are set are changed: a nil pointer, or
+// an empty management URL, leaves that setting alone.
+//
+// The management URL is in here because pointing a host with a remote-access
+// server running at another management identity hands the decision of who may
+// open a shell on it, or reach its desktop, to whoever runs that server, which is
+// the same power as enabling that server in the first place.
+type GuardedSettings struct {
+	ProfileName        string `json:"profileName"`
+	Username           string `json:"username"`
+	ManagementURL      string `json:"managementUrl,omitempty"`
+	ServerSSHAllowed   *bool  `json:"serverSshAllowed,omitempty"`
+	EnableSSHRoot      *bool  `json:"enableSshRoot,omitempty"`
+	DisableSSHAuth     *bool  `json:"disableSshAuth,omitempty"`
+	ServerVNCAllowed   *bool  `json:"serverVncAllowed,omitempty"`
+	DisableVNCApproval *bool  `json:"disableVncApproval,omitempty"`
+}
+
+// guardedSetting is one setting to change, in the two spellings this needs: the
+// one-shot's own flag, and the `netbird up` flag that does the same thing from a
+// terminal, for when there is no prompt to raise.
+type guardedSetting struct {
+	arg  string
+	flag string
+}
+
+// SetGuardedSettings applies settings the daemon refuses from an unprivileged
+// caller, by having the operating system run this binary again, elevated, to send
+// the same request the frontend would have sent itself.
+//
+// The user authorizes it at the platform's own prompt: the UAC consent dialog,
+// the macOS authentication dialog, or the polkit agent's. Any credentials are the
+// operating system's business; NetBird neither sees nor asks for them. Nothing
+// about the daemon's rules changes, and the elevated process is authorized like
+// any other privileged caller, from the identity the kernel reports for it.
+//
+// A declined prompt comes back as SaveOutcome.Declined with no error. When there is
+// no prompt to raise, or the elevated run failed, the error carries the command
+// that does the same thing from a terminal.
+func (s *Settings) SetGuardedSettings(ctx context.Context, p GuardedSettings) (SaveOutcome, error) {
+	settings := guardedSettings(p)
+	if len(settings) == 0 {
+		return SaveOutcome{}, &ClientError{
+			Code:  CodeElevationFailed,
+			Short: "no setting to apply",
+			Long:  "no setting to apply",
+		}
+	}
+
+	// The elevated run has no window and, on Linux, an environment pkexec has
+	// cleared, so what it writes to stderr is all there is to go on. It follows
+	// this process's level so that starting the app with --log-level debug says
+	// something about the run behind the prompt too.
+	args := append([]string{
+		"--" + FlagApplyPrivilegedSettings,
+		"--" + FlagDaemonAddr, s.daemonAddr,
+		"--" + FlagProfile, p.ProfileName,
+		"--" + FlagUser, p.Username,
+		"--" + FlagLogLevel, log.GetLevel().String(),
+	}, oneShotArgs(settings)...)
+
+	ctx, cancel := context.WithTimeout(ctx, elevationTimeout)
+	defer cancel()
+
+	// These changes hand out shells on this host, so both ends are logged: when the
+	// prompt went up, and what came of it. It is also the only account of a prompt
+	// that was slow to appear or never answered.
+	log.Infof("asking for privileges to apply %s", guardedSummary(p))
+
+	if err := s.elevator.Run(ctx, args...); err != nil {
+		return s.elevationOutcome(err, p)
+	}
+
+	log.Infof("applied %s with the privileges the user authorized", guardedSummary(p))
+	return SaveOutcome{}, nil
+}
+
+// elevationOutcome sorts what came back into the one normal ending and the two
+// that need reporting, with the command that does the same thing by hand.
+func (s *Settings) elevationOutcome(err error, p GuardedSettings) (SaveOutcome, error) {
+	switch {
+	case errors.Is(err, elevate.ErrDeclined):
+		// With the reason: an account that may not elevate at all lands here too,
+		// and the log is the only place that says which it was.
+		log.Infof("the elevation prompt for %s was declined: %v", guardedSummary(p), err)
+		return SaveOutcome{Declined: true}, nil
+	case errors.Is(err, elevate.ErrUnavailable):
+		log.Warnf("cannot ask for privileges to apply %s: %v", guardedSummary(p), err)
+		return SaveOutcome{}, &ClientError{
+			Code:    CodeElevationUnavailable,
+			Short:   s.classifier.translateShort(CodeElevationUnavailable),
+			Long:    err.Error(),
+			Command: guardedCommand(p),
+		}
+	default:
+		log.Errorf("applying %s with elevated privileges failed: %v", guardedSummary(p), err)
+		return SaveOutcome{}, &ClientError{
+			Code:    CodeElevationFailed,
+			Short:   s.classifier.translateShort(CodeElevationFailed),
+			Long:    err.Error(),
+			Command: guardedCommand(p),
+		}
+	}
+}
+
+// guardedSettings renders the settings that are actually being changed, from the
+// same table the one-shot parses them with: see oneshot.go.
+func guardedSettings(p GuardedSettings) []guardedSetting {
+	var settings []guardedSetting
+	for _, field := range guardedFields {
+		value, ok := field.read(p)
+		if !ok {
+			continue
+		}
+		settings = append(settings, guardedSetting{
+			arg:  "--" + field.flag + "=" + value,
+			flag: field.up(value),
+		})
+	}
+	return settings
+}
+
+func oneShotArgs(settings []guardedSetting) []string {
+	args := make([]string, 0, len(settings))
+	for _, setting := range settings {
+		args = append(args, setting.arg)
+	}
+	return args
+}
+
+func upFlags(settings []guardedSetting) []string {
+	flags := make([]string, 0, len(settings))
+	for _, setting := range settings {
+		flags = append(flags, setting.flag)
+	}
+	return flags
+}
+
+// guardedCommand is the elevated command line equivalent to the requested
+// change, the same shape the daemon names in its own refusals.
+func guardedCommand(p GuardedSettings) string {
+	settings := guardedSettings(p)
+	if len(settings) == 0 {
+		return ""
+	}
+	return ipcauth.UpCommand(strings.Join(upFlags(settings), " "))
+}
+
+// guardedSummary names the change for the log.
+func guardedSummary(p GuardedSettings) string {
+	return fmt.Sprintf("%v for profile %q", oneShotArgs(guardedSettings(p)), p.ProfileName)
+}

client/ui/services/guarded_test.go

@@ -0,0 +1,355 @@
+//go:build !android && !ios && !freebsd && !js
+
+package services
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"google.golang.org/genproto/googleapis/rpc/errdetails"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	gstatus "google.golang.org/grpc/status"
+
+	"github.com/netbirdio/netbird/client/internal/elevate"
+	"github.com/netbirdio/netbird/client/internal/ipcauth"
+	"github.com/netbirdio/netbird/client/proto"
+)
+
+// A Unix socket, so the daemon address is one that carries a caller's identity and
+// elevation is worth offering at all: see Settings.canElevate.
+const testDaemonAddr = "unix:///var/run/netbird.sock"
+
+// storedManagementURL is what the stub daemon already holds, so that a request
+// naming a different one is a change: see Settings.guardedChanges.
+const storedManagementURL = "https://stored.example.com"
+
+// stubElevator stands in for the platform's prompt: it records what would have run
+// and answers with a fixed outcome.
+type stubElevator struct {
+	outcome   error
+	available bool
+	calls     [][]string
+}
+
+func (e *stubElevator) Run(_ context.Context, args ...string) error {
+	e.calls = append(e.calls, args)
+	return e.outcome
+}
+
+func (e *stubElevator) Available() bool { return e.available }
+
+// stubDaemon implements only the RPCs under test. The embedded interface is nil, so
+// any other call panics rather than passing quietly.
+type stubDaemon struct {
+	proto.DaemonServiceClient
+	setConfig func(*proto.SetConfigRequest) error
+	// stored is what GetConfig reports, which is what a refused request's guarded
+	// settings are compared against.
+	stored   *proto.GetConfigResponse
+	requests []*proto.SetConfigRequest
+}
+
+func (d *stubDaemon) SetConfig(_ context.Context, in *proto.SetConfigRequest, _ ...grpc.CallOption) (*proto.SetConfigResponse, error) {
+	d.requests = append(d.requests, in)
+	if err := d.setConfig(in); err != nil {
+		return nil, err
+	}
+	return &proto.SetConfigResponse{}, nil
+}
+
+func (d *stubDaemon) GetConfig(_ context.Context, _ *proto.GetConfigRequest, _ ...grpc.CallOption) (*proto.GetConfigResponse, error) {
+	return d.stored, nil
+}
+
+type stubConn struct{ client proto.DaemonServiceClient }
+
+func (c stubConn) Client() (proto.DaemonServiceClient, error) { return c.client, nil }
+
+// privilegeRefusal is the error the daemon raises for a change it restricts to
+// root, detail and all: see server.privilegeError.
+func privilegeRefusal(t *testing.T) error {
+	t.Helper()
+
+	st, err := gstatus.New(codes.PermissionDenied, "Changing the management URL requires root.").
+		WithDetails(&errdetails.ErrorInfo{
+			Reason: ipcauth.ErrorReasonPrivilegeRequired,
+			Domain: ipcauth.ErrorDomain,
+			Metadata: map[string]string{
+				ipcauth.ErrorMetaSummary: "Changing the management URL requires root.",
+				ipcauth.ErrorMetaCommand: "sudo netbird down; sudo netbird up -m https://mgmt.example.com",
+			},
+		})
+	require.NoError(t, err, "build the refusal detail")
+	return st.Err()
+}
+
+func settingsWithElevation(t *testing.T, outcome error) (*Settings, *stubElevator) {
+	t.Helper()
+
+	elev := &stubElevator{outcome: outcome, available: true}
+	return &Settings{daemonAddr: testDaemonAddr, elevator: elev}, elev
+}
+
+// settingsRefusingOnce returns a Settings whose daemon refuses the first SetConfig
+// for want of privileges and accepts anything after it. Its stored config holds
+// another management server and no SSH grants, so a request naming either is a
+// change rather than a restatement.
+func settingsRefusingOnce(t *testing.T, elev *stubElevator) (*Settings, *stubDaemon) {
+	t.Helper()
+
+	refusal := privilegeRefusal(t)
+	daemon := &stubDaemon{stored: &proto.GetConfigResponse{ManagementUrl: storedManagementURL}}
+	daemon.setConfig = func(*proto.SetConfigRequest) error {
+		if len(daemon.requests) == 1 {
+			return refusal
+		}
+		return nil
+	}
+	return &Settings{conn: stubConn{client: daemon}, daemonAddr: testDaemonAddr, elevator: elev}, daemon
+}
+
+func TestSetGuardedSettingsPassesOnlyTheChangedSettings(t *testing.T) {
+	s, elev := settingsWithElevation(t, nil)
+
+	root := true
+	outcome, err := s.SetGuardedSettings(context.Background(), GuardedSettings{
+		ProfileName:   "work",
+		Username:      "vma",
+		EnableSSHRoot: &root,
+	})
+	require.NoError(t, err)
+	assert.False(t, outcome.Declined, "the prompt was answered")
+
+	want := []string{
+		"--" + FlagApplyPrivilegedSettings,
+		"--" + FlagDaemonAddr, testDaemonAddr,
+		"--" + FlagProfile, "work",
+		"--" + FlagUser, "vma",
+		"--" + FlagLogLevel, log.GetLevel().String(),
+		"--" + FlagEnableSSHRoot + "=true",
+	}
+	require.Len(t, elev.calls, 1, "one prompt for one change")
+	assert.Equal(t, want, elev.calls[0], "elevated arguments")
+
+	// argv[1] is what the polkit action is pinned to, so the marker has to stay
+	// first however the rest of the line grows.
+	assert.Equal(t, "--"+FlagApplyPrivilegedSettings, elev.calls[0][0], "the flag polkit matches on")
+}
+
+// Turning a setting off has to be as explicit as turning it on: a bare flag would
+// read as "on" to the one-shot's parser.
+func TestSetGuardedSettingsSpellsOutFalse(t *testing.T) {
+	s, elev := settingsWithElevation(t, nil)
+
+	off := false
+	_, err := s.SetGuardedSettings(context.Background(), GuardedSettings{
+		ProfileName:      "default",
+		ServerSSHAllowed: &off,
+		DisableSSHAuth:   &off,
+	})
+	require.NoError(t, err)
+
+	args := elev.calls[0]
+	assert.Contains(t, args, "--"+FlagAllowServerSSH+"=false", "the setting being switched off")
+	assert.Contains(t, args, "--"+FlagDisableSSHAuth+"=false", "the setting being switched off")
+	assert.NotContains(t, args, "--"+FlagEnableSSHRoot+"=false", "no flag for a setting nobody touched")
+}
+
+func TestSetGuardedSettingsPassesTheManagementURL(t *testing.T) {
+	s, elev := settingsWithElevation(t, nil)
+
+	_, err := s.SetGuardedSettings(context.Background(), GuardedSettings{
+		ProfileName:   "default",
+		ManagementURL: "https://mgmt.example.com:33073",
+	})
+	require.NoError(t, err)
+
+	assert.Contains(t, elev.calls[0], "--"+FlagManagementURL+"=https://mgmt.example.com:33073",
+		"the management URL to point the profile at")
+}
+
+func TestSetGuardedSettingsWithoutASettingDoesNotElevate(t *testing.T) {
+	s, elev := settingsWithElevation(t, nil)
+
+	_, err := s.SetGuardedSettings(context.Background(), GuardedSettings{ProfileName: "default"})
+
+	require.Error(t, err, "nothing to apply is not something to prompt for")
+	assert.Empty(t, elev.calls, "no prompt at all")
+}
+
+// A declined prompt is the one ending that is not an error: reporting it as one
+// would have every cancelled prompt logged as a failure.
+func TestSetGuardedSettingsReportsADeclinedPromptAsAnOutcome(t *testing.T) {
+	s, _ := settingsWithElevation(t, elevate.ErrDeclined)
+
+	root := true
+	outcome, err := s.SetGuardedSettings(context.Background(), GuardedSettings{
+		ProfileName:   "default",
+		EnableSSHRoot: &root,
+	})
+
+	require.NoError(t, err, "the user was asked and answered; nothing went wrong")
+	assert.True(t, outcome.Declined, "nothing was applied")
+}
+
+func TestSetGuardedSettingsMapsFailures(t *testing.T) {
+	tests := []struct {
+		name     string
+		outcome  error
+		wantCode string
+	}{
+		{
+			// Nothing to raise a prompt with: the user needs the command.
+			name:     "no mechanism falls back to the command",
+			outcome:  elevate.ErrUnavailable,
+			wantCode: CodeElevationUnavailable,
+		},
+		{
+			name:     "a failed run falls back to the command",
+			outcome:  errors.New("elevated netbird exited with 1"),
+			wantCode: CodeElevationFailed,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			s, _ := settingsWithElevation(t, tt.outcome)
+
+			root := true
+			_, err := s.SetGuardedSettings(context.Background(), GuardedSettings{
+				ProfileName:   "default",
+				EnableSSHRoot: &root,
+			})
+
+			var clientErr *ClientError
+			require.ErrorAs(t, err, &clientErr, "the frontend needs a code to act on")
+			assert.Equal(t, tt.wantCode, clientErr.Code, "error code")
+			assert.Contains(t, clientErr.Command, "--"+FlagEnableSSHRoot+"=true",
+				"the setting in the fallback command")
+			assert.Contains(t, clientErr.Command, "netbird up", "the fallback command")
+		})
+	}
+}
+
+// Changing the management URL is only privileged while the host runs the SSH
+// server, which no control can know up front, so the refusal is what triggers the
+// prompt. The original request goes again afterwards, so the fields the one-shot
+// does not understand are applied too.
+func TestSetConfigElevatesAfterARefusalAndRetries(t *testing.T) {
+	elev := &stubElevator{available: true}
+	s, daemon := settingsRefusingOnce(t, elev)
+
+	mtu := int64(1280)
+	outcome, err := s.SetConfig(context.Background(), SetConfigParams{
+		ProfileName:   "default",
+		ManagementURL: "https://mgmt.example.com",
+		MTU:           &mtu,
+	})
+	require.NoError(t, err)
+	assert.False(t, outcome.Declined, "the prompt was answered")
+
+	require.Len(t, elev.calls, 1, "one prompt")
+	assert.Contains(t, elev.calls[0], "--"+FlagManagementURL+"=https://mgmt.example.com",
+		"the guarded part of the request")
+	require.Len(t, daemon.requests, 2, "the refused request and the retry")
+	assert.Equal(t, mtu, daemon.requests[1].GetMtu(),
+		"the retry carries the rest of the request, which the one-shot does not understand")
+}
+
+func TestSetConfigDoesNotRetryWhenTheUserDeclines(t *testing.T) {
+	elev := &stubElevator{outcome: elevate.ErrDeclined, available: true}
+	s, daemon := settingsRefusingOnce(t, elev)
+
+	outcome, err := s.SetConfig(context.Background(), SetConfigParams{
+		ProfileName:   "default",
+		ManagementURL: "https://mgmt.example.com",
+	})
+
+	require.NoError(t, err, "a declined prompt is not an error")
+	assert.True(t, outcome.Declined, "nothing was applied")
+	assert.Len(t, daemon.requests, 1, "only the refused request")
+}
+
+// With no prompt to raise, the refusal is reported as the daemon wrote it, which is
+// the guidance that was there before elevation existed.
+func TestSetConfigReportsTheRefusalWhenItCannotElevate(t *testing.T) {
+	elev := &stubElevator{available: false}
+	s, _ := settingsRefusingOnce(t, elev)
+
+	_, err := s.SetConfig(context.Background(), SetConfigParams{
+		ProfileName:   "default",
+		ManagementURL: "https://mgmt.example.com",
+	})
+
+	var clientErr *ClientError
+	require.ErrorAs(t, err, &clientErr)
+	assert.Equal(t, "privilege_required", clientErr.Code, "error code")
+	assert.Contains(t, clientErr.Command, "netbird up -m https://mgmt.example.com",
+		"the daemon's own command")
+	assert.Empty(t, elev.calls, "no prompt where there is none to raise")
+}
+
+// One authorization must buy only the change the user made. A settings form
+// submits every field it holds, so most of a refused request restates what the
+// daemon already has, and elevating those too would apply a guarded setting the
+// user never touched — a value gone stale since the form loaded above all.
+func TestSetConfigElevatesOnlyTheGuardedSettingsThatChange(t *testing.T) {
+	elev := &stubElevator{available: true}
+	s, _ := settingsRefusingOnce(t, elev)
+
+	on, off := true, false
+	_, err := s.SetConfig(context.Background(), SetConfigParams{
+		ProfileName:      "default",
+		ManagementURL:    storedManagementURL,
+		ServerSSHAllowed: &off,
+		EnableSSHRoot:    &off,
+		DisableSSHAuth:   &on,
+	})
+	require.NoError(t, err)
+
+	require.Len(t, elev.calls, 1, "one prompt")
+	args := elev.calls[0]
+	assert.Contains(t, args, "--"+FlagDisableSSHAuth+"=true", "the setting that changes")
+	assert.NotContains(t, args, "--"+FlagManagementURL+"="+storedManagementURL,
+		"a management URL the daemon already holds")
+	assert.NotContains(t, args, "--"+FlagAllowServerSSH+"=false", "a setting already off")
+	assert.NotContains(t, args, "--"+FlagEnableSSHRoot+"=false", "a setting already off")
+}
+
+// A request that changes no guarded setting has nothing an elevated run could
+// apply, so the refusal must have come from somewhere a prompt cannot reach.
+func TestSetConfigDoesNotElevateWhenNoGuardedSettingChanges(t *testing.T) {
+	elev := &stubElevator{available: true}
+	s, _ := settingsRefusingOnce(t, elev)
+
+	off := false
+	_, err := s.SetConfig(context.Background(), SetConfigParams{
+		ProfileName:      "default",
+		ManagementURL:    storedManagementURL,
+		ServerSSHAllowed: &off,
+	})
+
+	var clientErr *ClientError
+	require.ErrorAs(t, err, &clientErr)
+	assert.Equal(t, "privilege_required", clientErr.Code, "error code")
+	assert.Empty(t, elev.calls, "no prompt for a change nobody made")
+}
+
+// A refusal with nothing in the request the one-shot could apply: the daemon
+// cannot see who is calling, and being root would not help either.
+func TestSetConfigReportsARefusalWithNothingToElevate(t *testing.T) {
+	elev := &stubElevator{available: true}
+	s, _ := settingsRefusingOnce(t, elev)
+
+	_, err := s.SetConfig(context.Background(), SetConfigParams{ProfileName: "default"})
+
+	var clientErr *ClientError
+	require.ErrorAs(t, err, &clientErr)
+	assert.Equal(t, "privilege_required", clientErr.Code, "error code")
+	assert.Empty(t, elev.calls, "no prompt")
+}

client/ui/services/oneshot.go

@@ -0,0 +1,245 @@
+//go:build !android && !ios && !freebsd && !js
+
+package services
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"fmt"
+	"os"
+	"strconv"
+	"time"
+
+	gstatus "google.golang.org/grpc/status"
+
+	"github.com/netbirdio/netbird/client/internal/elevate"
+	"github.com/netbirdio/netbird/client/internal/profilemanager"
+	"github.com/netbirdio/netbird/client/proto"
+	"github.com/netbirdio/netbird/util"
+)
+
+// The other end of SetGuardedSettings: the mode this binary runs itself in,
+// elevated, to apply the settings the daemon restricts to root/administrator.
+//
+// Both ends are here on purpose. What may be changed this way is an allowlist, and
+// an allowlist declared twice is one that will eventually disagree with itself, so
+// the arguments are rendered and parsed from a single table: guardedFields. Adding
+// a setting is one row; nothing generic passes through, and no field outside the
+// table can be reached with an elevated request no matter what lands on the command
+// line.
+
+// oneShotTimeout bounds the whole one-shot: connect, one RPC, exit. Generous
+// because the user has just waited for an authentication dialog, and a failure here
+// costs them the entire round trip.
+const oneShotTimeout = 30 * time.Second
+
+// Exit codes the parent reads where the platform gives it one.
+const (
+	exitOK      = 0
+	exitFailure = 1
+	exitUsage   = 2
+)
+
+// guardedField is one setting the one-shot understands, in the two spellings it
+// needs and with the two halves of its plumbing.
+type guardedField struct {
+	// flag names it on the one-shot's command line.
+	flag  string
+	usage string
+	// read returns the value to send and whether the caller asked for this setting
+	// at all.
+	read func(GuardedSettings) (string, bool)
+	// write parses a value from the command line onto the request. It is the only
+	// thing that validates the value, so it fails on anything it does not
+	// recognise rather than guessing.
+	write func(*proto.SetConfigRequest, string) error
+	// up renders the equivalent `netbird up` flag, for the fallback command shown
+	// when there is no prompt to raise.
+	up func(value string) string
+}
+
+var guardedFields = []guardedField{
+	{
+		flag:  FlagManagementURL,
+		usage: "Management server the profile registers with.",
+		read:  func(p GuardedSettings) (string, bool) { return p.ManagementURL, p.ManagementURL != "" },
+		write: func(req *proto.SetConfigRequest, value string) error {
+			// Parsed with the config layer's own parser, so what the elevated run
+			// accepts cannot drift from what the daemon would store.
+			if _, err := profilemanager.ParseServiceURL("Management URL", value); err != nil {
+				return err
+			}
+			req.ManagementUrl = value
+			return nil
+		},
+		// The daemon names this one as `-m <url>` in its own refusals.
+		up: func(value string) string { return "-m " + value },
+	},
+	boolField(FlagAllowServerSSH, "Run the NetBird SSH server.",
+		func(p GuardedSettings) *bool { return p.ServerSSHAllowed },
+		func(req *proto.SetConfigRequest, v *bool) { req.ServerSSHAllowed = v }),
+	boolField(FlagEnableSSHRoot, "Allow SSH sessions to privileged accounts.",
+		func(p GuardedSettings) *bool { return p.EnableSSHRoot },
+		func(req *proto.SetConfigRequest, v *bool) { req.EnableSSHRoot = v }),
+	boolField(FlagDisableSSHAuth, "Accept SSH sessions without authentication.",
+		func(p GuardedSettings) *bool { return p.DisableSSHAuth },
+		func(req *proto.SetConfigRequest, v *bool) { req.DisableSSHAuth = v }),
+	boolField(FlagAllowServerVNC, "Run the NetBird VNC server.",
+		func(p GuardedSettings) *bool { return p.ServerVNCAllowed },
+		func(req *proto.SetConfigRequest, v *bool) { req.ServerVNCAllowed = v }),
+	boolField(FlagDisableVNCApproval, "Accept VNC sessions without asking the console user.",
+		func(p GuardedSettings) *bool { return p.DisableVNCApproval },
+		func(req *proto.SetConfigRequest, v *bool) { req.DisableVNCApproval = v }),
+}
+
+// fieldValue is a flag that remembers whether it was given, and requires a value:
+// the renderer always writes one, so a bare flag is a caller that got it wrong.
+type fieldValue struct {
+	set   bool
+	value string
+}
+
+func (v *fieldValue) String() string {
+	if v == nil {
+		return ""
+	}
+	return v.value
+}
+
+func (v *fieldValue) Set(value string) error {
+	v.set, v.value = true, value
+	return nil
+}
+
+// boolField describes a setting that is on or off. The value is always spelled out,
+// so that turning a setting off is as unambiguous as turning it on and a flag with
+// no value is a mistake rather than an "on".
+func boolField(
+	name, usage string,
+	read func(GuardedSettings) *bool,
+	write func(*proto.SetConfigRequest, *bool),
+) guardedField {
+	return guardedField{
+		flag:  name,
+		usage: usage,
+		read: func(p GuardedSettings) (string, bool) {
+			value := read(p)
+			if value == nil {
+				return "", false
+			}
+			return strconv.FormatBool(*value), true
+		},
+		write: func(req *proto.SetConfigRequest, value string) error {
+			parsed, err := strconv.ParseBool(value)
+			if err != nil {
+				return fmt.Errorf("parse %q as a boolean: %w", value, err)
+			}
+			write(req, &parsed)
+			return nil
+		},
+		up: func(value string) string { return "--" + name + "=" + value },
+	}
+}
+
+// IsPrivilegedSettingsRun reports whether this process was started as the one-shot.
+// The flag is a marker rather than a value, so only the bare forms count: reading a
+// value would mean "--flag=false" started it too.
+func IsPrivilegedSettingsRun(args []string) bool {
+	for _, arg := range args {
+		if arg == "--"+FlagApplyPrivilegedSettings || arg == "-"+FlagApplyPrivilegedSettings {
+			return true
+		}
+	}
+	return false
+}
+
+// RunPrivilegedSettings applies the requested settings and returns the process exit
+// code. connect dials the daemon, which is the caller's business because only it
+// knows how this build talks to it.
+//
+// Everything it reports goes to stderr, which is what the parent captures where the
+// platform lets it. On success it says so on standard output, because macOS gives
+// the parent no exit status to read: see elevate.AppliedMarker.
+func RunPrivilegedSettings(args []string, connect func(addr string) (proto.DaemonServiceClient, error)) int {
+	fs := flag.NewFlagSet("netbird-ui --"+FlagApplyPrivilegedSettings, flag.ContinueOnError)
+	fs.Bool(FlagApplyPrivilegedSettings, false, "Apply the settings the daemon restricts to root/administrator and exit.")
+	daemonAddr := fs.String(FlagDaemonAddr, "", "Daemon gRPC address: unix:///path, npipe://name or tcp://host:port")
+	logLevel := fs.String(FlagLogLevel, "info", "Log level: trace|debug|info|warn|error.")
+	profile := fs.String(FlagProfile, "", "Profile to change.")
+	username := fs.String(FlagUser, "", "Owner of the profile.")
+
+	values := make([]fieldValue, len(guardedFields))
+	for i, field := range guardedFields {
+		fs.Var(&values[i], field.flag, field.usage)
+	}
+
+	if err := fs.Parse(args); err != nil {
+		return exitUsage
+	}
+
+	if err := util.InitLog(*logLevel, "console"); err != nil {
+		fmt.Fprintf(os.Stderr, "init log: %v\n", err)
+		return exitFailure
+	}
+
+	req, err := privilegedRequest(*profile, *username, values)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+		return exitUsage
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), oneShotTimeout)
+	defer cancel()
+
+	if err := applyPrivilegedSettings(ctx, *daemonAddr, req, connect); err != nil {
+		fmt.Fprintf(os.Stderr, "apply settings: %v\n", err)
+		return exitFailure
+	}
+
+	fmt.Fprintln(os.Stdout, elevate.AppliedMarker)
+	return exitOK
+}
+
+// privilegedRequest builds the request from the flags that were given, and refuses
+// one that asks for nothing.
+func privilegedRequest(profile, username string, values []fieldValue) (*proto.SetConfigRequest, error) {
+	req := &proto.SetConfigRequest{ProfileName: profile, Username: username}
+
+	given := 0
+	for i, field := range guardedFields {
+		if !values[i].set {
+			continue
+		}
+		if err := field.write(req, values[i].value); err != nil {
+			return nil, fmt.Errorf("--%s: %w", field.flag, err)
+		}
+		given++
+	}
+	if given == 0 {
+		return nil, errors.New("no setting to apply")
+	}
+	return req, nil
+}
+
+func applyPrivilegedSettings(
+	ctx context.Context,
+	daemonAddr string,
+	req *proto.SetConfigRequest,
+	connect func(addr string) (proto.DaemonServiceClient, error),
+) error {
+	client, err := connect(daemonAddr)
+	if err != nil {
+		return err
+	}
+	if _, err := client.SetConfig(ctx, req); err != nil {
+		// Unwrapped: the daemon's message is written for a person, and a refusal
+		// elevation cannot fix has to say so where the parent can read it off
+		// stderr.
+		return errors.New(gstatus.Convert(err).Message())
+	}
+	return nil
+}
+
+// interface guard: the one-shot's flags are flag.Value.
+var _ flag.Value = (*fieldValue)(nil)

client/ui/services/oneshot_test.go

@@ -0,0 +1,151 @@
+//go:build !android && !ios && !freebsd && !js
+
+package services
+
+import (
+	"flag"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/netbirdio/netbird/client/proto"
+)
+
+func TestIsPrivilegedSettingsRun(t *testing.T) {
+	tests := []struct {
+		name string
+		args []string
+		want bool
+	}{
+		{name: "no arguments"},
+		{name: "double dash", args: []string{"--" + FlagApplyPrivilegedSettings}, want: true},
+		{name: "single dash", args: []string{"-" + FlagApplyPrivilegedSettings}, want: true},
+		{
+			name: "among other flags",
+			args: []string{"--daemon-addr", "unix:///tmp/x.sock", "--" + FlagApplyPrivilegedSettings},
+			want: true,
+		},
+		// A marker, not a value: the caller never passes one, and reading a value
+		// would mean "--flag=false" started the one-shot too.
+		{name: "with a value", args: []string{"--" + FlagApplyPrivilegedSettings + "=true"}},
+		{name: "unrelated flags", args: []string{"--log-level", "debug"}},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, IsPrivilegedSettingsRun(tt.args), "args %v", tt.args)
+		})
+	}
+}
+
+// What SetGuardedSettings renders has to be what the one-shot reads back, for every
+// setting in the table. This is the property that keeps the two ends of an allowlist
+// from drifting, so it is checked field by field rather than by example.
+func TestGuardedFieldsRoundTrip(t *testing.T) {
+	on, off := true, false
+	tests := []struct {
+		name     string
+		settings GuardedSettings
+		want     func(*testing.T, *proto.SetConfigRequest)
+	}{
+		{
+			name:     "management url",
+			settings: GuardedSettings{ManagementURL: "https://mgmt.example.com:33073"},
+			want: func(t *testing.T, req *proto.SetConfigRequest) {
+				assert.Equal(t, "https://mgmt.example.com:33073", req.GetManagementUrl())
+			},
+		},
+		{
+			name:     "ssh server on",
+			settings: GuardedSettings{ServerSSHAllowed: &on},
+			want: func(t *testing.T, req *proto.SetConfigRequest) {
+				require.NotNil(t, req.ServerSSHAllowed)
+				assert.True(t, *req.ServerSSHAllowed)
+			},
+		},
+		{
+			name:     "ssh root off",
+			settings: GuardedSettings{EnableSSHRoot: &off},
+			want: func(t *testing.T, req *proto.SetConfigRequest) {
+				require.NotNil(t, req.EnableSSHRoot, "an explicit false must survive, not read as absent")
+				assert.False(t, *req.EnableSSHRoot)
+			},
+		},
+		{
+			name:     "ssh auth off",
+			settings: GuardedSettings{DisableSSHAuth: &on},
+			want: func(t *testing.T, req *proto.SetConfigRequest) {
+				require.NotNil(t, req.DisableSSHAuth)
+				assert.True(t, *req.DisableSSHAuth)
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			req := parseRendered(t, tt.settings)
+			tt.want(t, req)
+		})
+	}
+}
+
+// A setting nobody asked about must not arrive at the daemon at all: sending its
+// zero value would change it.
+func TestGuardedFieldsCarryOnlyWhatWasAsked(t *testing.T) {
+	on := true
+	req := parseRendered(t, GuardedSettings{ProfileName: "work", EnableSSHRoot: &on})
+
+	assert.Equal(t, "work", req.GetProfileName(), "profile")
+	require.NotNil(t, req.EnableSSHRoot)
+	assert.Nil(t, req.ServerSSHAllowed, "untouched setting")
+	assert.Nil(t, req.DisableSSHAuth, "untouched setting")
+	assert.Empty(t, req.GetManagementUrl(), "untouched setting")
+}
+
+func TestPrivilegedRequestRejectsAnEmptyChange(t *testing.T) {
+	_, err := privilegedRequest("default", "vma", make([]fieldValue, len(guardedFields)))
+	require.Error(t, err, "nothing to apply is not a request worth sending as root")
+}
+
+// A value the table cannot parse is refused rather than guessed at.
+func TestPrivilegedRequestRejectsAnUnparseableValue(t *testing.T) {
+	values := make([]fieldValue, len(guardedFields))
+	for i, field := range guardedFields {
+		if field.flag != FlagEnableSSHRoot {
+			continue
+		}
+		require.NoError(t, values[i].Set("perhaps"))
+	}
+
+	_, err := privilegedRequest("default", "vma", values)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), FlagEnableSSHRoot, "which flag was wrong")
+}
+
+// parseRendered puts the settings through both ends: rendered as the arguments the
+// elevated process is given, then parsed by a flag set registered from the same
+// table, which is what the one-shot itself parses them with. Anything hand-rolled
+// here would pin down a parser nothing uses.
+func parseRendered(t *testing.T, p GuardedSettings) *proto.SetConfigRequest {
+	t.Helper()
+
+	rendered := guardedSettings(p)
+	require.NotEmpty(t, rendered, "nothing rendered for %+v", p)
+
+	args := make([]string, 0, len(rendered))
+	for _, setting := range rendered {
+		args = append(args, setting.arg)
+	}
+
+	fs := flag.NewFlagSet(t.Name(), flag.ContinueOnError)
+	values := make([]fieldValue, len(guardedFields))
+	for i, field := range guardedFields {
+		fs.Var(&values[i], field.flag, field.usage)
+	}
+	require.NoError(t, fs.Parse(args), "the one-shot's own flag set must accept %v", args)
+
+	req, err := privilegedRequest(p.ProfileName, p.Username, values)
+	require.NoError(t, err)
+	return req
+}

client/ui/services/settings.go

@@ -46,12 +46,19 @@ type Restrictions struct {
 }
 
 // Privilege tells the frontend whether this process may perform the changes the
-// daemon restricts to root/administrator, and carries the command for each so a
-// disabled control can show the way to do it.
+// daemon restricts to root/administrator, whether it can ask the operating
+// system for the privileges instead, and the command for each so a control that
+// can do neither can still show the way.
 type Privilege struct {
 	Privileged bool `json:"privileged"`
-	// Actor names what the operation requires ("root", "administrator privileges").
-	Actor string `json:"actor"`
+	// ActorKey identifies the principal the operation requires without wording it,
+	// so the frontend can name it in the user's language: see
+	// ipcauth.PrivilegedActorKey. The words are not sent, because English ones
+	// cannot be dropped into a translated sentence.
+	ActorKey string `json:"actorKey"`
+	// CanElevate reports whether a guarded control can offer to authorize the
+	// change through the platform's own prompt: see SetGuardedSettings.
+	CanElevate bool `json:"canElevate"`
 	// Commands equivalent to the settings the daemon guards, ready to copy.
 	AllowSSHServer     string `json:"allowSshServer"`
 	EnableSSHRoot      string `json:"enableSshRoot"`
@@ -136,6 +143,9 @@ type Settings struct {
 	// daemonAddr is where the daemon listens, used to tell whether it runs as
 	// this user and would therefore authorize us: see Privilege.
 	daemonAddr string
+	// elevator raises the platform's privilege prompt when a change needs more
+	// rights than this process has.
+	elevator elevator
 }
 
 func NewSettings(conn DaemonConn, translator ErrorTranslator, prefs LanguagePreference, daemonAddr string) *Settings {
@@ -143,6 +153,7 @@ func NewSettings(conn DaemonConn, translator ErrorTranslator, prefs LanguagePref
 		conn:       conn,
 		classifier: errorClassifier{translator: translator, prefs: prefs},
 		daemonAddr: daemonAddr,
+		elevator:   osElevator{},
 	}
 }
 
@@ -190,10 +201,10 @@ func (s *Settings) GetConfig(ctx context.Context, p ConfigParams) (Config, error
 	}, nil
 }
 
-func (s *Settings) SetConfig(ctx context.Context, p SetConfigParams) error {
+func (s *Settings) SetConfig(ctx context.Context, p SetConfigParams) (SaveOutcome, error) {
 	cli, err := s.conn.Client()
 	if err != nil {
-		return err
+		return SaveOutcome{}, err
 	}
 	req := &proto.SetConfigRequest{
 		ProfileName:                   p.ProfileName,
@@ -227,19 +238,94 @@ func (s *Settings) SetConfig(ctx context.Context, p SetConfigParams) error {
 		SshJWTCacheTTL:                p.SSHJWTCacheTTL,
 	}
 	if _, err := cli.SetConfig(ctx, req); err != nil {
+		if _, refused := privilegeErrorInfo(err); refused {
+			return s.setConfigElevated(ctx, p, req, err)
+		}
 		// Classified so the frontend gets the daemon's guidance instead of the
-		// gRPC envelope, which is what a refused privileged change looks like.
-		return s.classifier.classify(err)
+		// gRPC envelope.
+		return SaveOutcome{}, s.classifier.classify(err)
 	}
-	return nil
+	return SaveOutcome{}, nil
+}
+
+// setConfigElevated answers a request the daemon refused for want of privileges by
+// asking the user to authorize it, and sending it again if they do. It is the same
+// offer the SSH settings make up front, for the changes a control cannot know are
+// guarded until it is told: repointing a profile at another management server is
+// only privileged while that host runs the SSH server.
+//
+// Two steps, because the elevated one-shot deliberately understands only the
+// settings the daemon guards: it applies those, and the original request then goes
+// through as this user, its privileged parts now asking for nothing that is not
+// already stored. Nothing was applied by the refused attempt — the daemon decides
+// before it writes — so there is no half-applied state to undo either way.
+func (s *Settings) setConfigElevated(ctx context.Context, p SetConfigParams, req *proto.SetConfigRequest, refusal error) (SaveOutcome, error) {
+	if !s.canElevate() {
+		return SaveOutcome{}, s.classifier.classify(refusal)
+	}
+
+	guarded, err := s.guardedChanges(ctx, p)
+	if err != nil {
+		log.Warnf("cannot tell which guarded settings this request changes: %v", err)
+		return SaveOutcome{}, s.classifier.classify(refusal)
+	}
+	if len(guardedSettings(guarded)) == 0 {
+		// Refused over something no prompt can settle, such as a control channel
+		// that carries no caller identity. Report the daemon's own guidance.
+		return SaveOutcome{}, s.classifier.classify(refusal)
+	}
+
+	outcome, err := s.SetGuardedSettings(ctx, guarded)
+	if err != nil || outcome.Declined {
+		return outcome, err
+	}
+
+	cli, err := s.conn.Client()
+	if err != nil {
+		return SaveOutcome{}, err
+	}
+	if _, err := cli.SetConfig(ctx, req); err != nil {
+		return SaveOutcome{}, s.classifier.classify(err)
+	}
+	return SaveOutcome{}, nil
+}
+
+// guardedChanges is the guarded part of a request, reduced to what it actually
+// changes.
+//
+// A settings form submits every field it holds, so a request restates values the
+// daemon already has. Carrying those into the elevated run would spend one
+// authorization on more than the user asked for, and a value that has gone stale
+// since the form was loaded would spend it on something they never asked about.
+func (s *Settings) guardedChanges(ctx context.Context, p SetConfigParams) (GuardedSettings, error) {
+	stored, err := s.GetConfig(ctx, ConfigParams{ProfileName: p.ProfileName, Username: p.Username})
+	if err != nil {
+		return GuardedSettings{}, fmt.Errorf("read the stored config: %w", err)
+	}
+
+	guarded := GuardedSettings{
+		ProfileName:        p.ProfileName,
+		Username:           p.Username,
+		ServerSSHAllowed:   changedFlag(p.ServerSSHAllowed, stored.ServerSSHAllowed),
+		EnableSSHRoot:      changedFlag(p.EnableSSHRoot, stored.EnableSSHRoot),
+		DisableSSHAuth:     changedFlag(p.DisableSSHAuth, stored.DisableSSHAuth),
+		ServerVNCAllowed:   changedFlag(p.ServerVNCAllowed, stored.ServerVNCAllowed),
+		DisableVNCApproval: changedFlag(p.DisableVNCApproval, stored.DisableVNCApproval),
+	}
+	// An empty URL leaves the setting alone, which is the daemon's rule too.
+	if p.ManagementURL != "" && p.ManagementURL != stored.ManagementURL {
+		guarded.ManagementURL = p.ManagementURL
+	}
+	return guarded, nil
 }
 
 // Privilege reports whether this UI process could carry out the changes the
-// daemon restricts to root/administrator, and the command that performs each of
-// the ones users hit in the SSH and VNC settings. It applies the daemon's own rule to what it can
-// see locally, so the frontend can present those controls as unavailable up front
-// instead of letting a save fail. No daemon round-trip, so it also works while the
-// daemon is down.
+// daemon restricts to root/administrator, whether it can instead ask the
+// operating system for the privileges when the user wants one of them, and the
+// command that performs each of the ones users hit in the SSH and VNC settings.
+// It applies the daemon's own rule to what it can see locally, so the frontend
+// can decide up front how to present those controls instead of letting a save
+// fail. No daemon round-trip, so it also works while the daemon is down.
 //
 // Being root or an elevated administrator is one way. The other is running as the
 // daemon's own user while the daemon is unprivileged, which the daemon accepts
@@ -249,20 +335,21 @@ func (s *Settings) SetConfig(ctx context.Context, p SetConfigParams) error {
 func (s *Settings) Privilege() Privilege {
 	id, err := ipcauth.CurrentProcessIdentity()
 	if err != nil {
-		// Fail closed: report unprivileged, which only ever disables controls.
+		// Fail closed: report unprivileged, which only ever asks for more.
 		log.Warnf("cannot read this process's identity, treating it as unprivileged: %v", err)
-		return newPrivilege(false)
+		return s.newPrivilege(false)
 	}
 	if id.IsPrivileged() {
-		return newPrivilege(true)
+		return s.newPrivilege(true)
 	}
-	return newPrivilege(daemonaddr.DaemonRunsAsSelf(s.daemonAddr))
+	return s.newPrivilege(daemonaddr.DaemonRunsAsSelf(s.daemonAddr))
 }
 
-func newPrivilege(privileged bool) Privilege {
+func (s *Settings) newPrivilege(privileged bool) Privilege {
 	return Privilege{
 		Privileged:         privileged,
-		Actor:              ipcauth.PrivilegedActor(),
+		ActorKey:           ipcauth.PrivilegedActorKey(),
+		CanElevate:         s.canElevate(),
 		AllowSSHServer:     ipcauth.UpCommand("--allow-server-ssh"),
 		EnableSSHRoot:      ipcauth.UpCommand("--enable-ssh-root"),
 		DisableSSHAuth:     ipcauth.UpCommand("--disable-ssh-auth"),
@@ -271,6 +358,19 @@ func newPrivilege(privileged bool) Privilege {
 	}
 }
 
+// canElevate reports whether offering the platform's elevation prompt would get
+// the user anywhere. It needs a mechanism to raise the prompt with and a control
+// channel that tells the daemon who is calling: on loopback TCP the daemon
+// refuses these changes to everybody, root included, so a prompt there would
+// only waste the user's password.
+func (s *Settings) canElevate() bool {
+	if !daemonaddr.CarriesIdentity(s.daemonAddr) {
+		log.Debugf("not offering elevation: the daemon address %s carries no caller identity", s.daemonAddr)
+		return false
+	}
+	return s.elevator.Available()
+}
+
 func (s *Settings) GetRestrictions(ctx context.Context) (Restrictions, error) {
 	cli, err := s.conn.Client()
 	if err != nil {
@@ -303,6 +403,15 @@ func (s *Settings) GetRestrictions(ctx context.Context) (Restrictions, error) {
 	return r, nil
 }
 
+// changedFlag returns requested only when it differs from what is stored, so a
+// setting the request merely restates is left out of the elevated run.
+func changedFlag(requested *bool, stored bool) *bool {
+	if requested == nil || *requested == stored {
+		return nil
+	}
+	return requested
+}
+
 func applyMDMRestrictions(mdm *MDMFields, cfgResp *proto.GetConfigResponse) {
 	managed := cfgResp.GetMDMManagedFields()
 	if len(managed) == 0 {