// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package dns import ( "bytes" "context" "fmt" "math/rand" "net/netip" "strings" "testing" "time" "golang.org/x/sys/windows" "golang.org/x/sys/windows/registry" "tailscale.com/util/dnsname" "tailscale.com/util/winutil" ) const testGPRuleID = "{7B1B6151-84E6-41A3-8967-62F7F7B45687}" func TestHostFileNewLines(t *testing.T) { in := []byte("#foo\r\n#bar\n#baz\n") want := []byte("#foo\r\n#bar\r\n#baz\r\n") got, err := setTailscaleHosts(in, nil) if err != nil { t.Fatal(err) } if !bytes.Equal(got, want) { t.Errorf("got %q, want %q\n", got, want) } } func TestManagerWindowsLocal(t *testing.T) { if !isWindows10OrBetter() || !winutil.IsCurrentProcessElevated() { t.Skipf("test requires running as elevated user on Windows 10+") } runTest(t, true) } func TestManagerWindowsGP(t *testing.T) { if !isWindows10OrBetter() || !winutil.IsCurrentProcessElevated() { t.Skipf("test requires running as elevated user on Windows 10+") } checkGPNotificationsWork(t) // Make sure group policy is refreshed before this test exits but after we've // cleaned everything else up. defer procRefreshPolicyEx.Call(uintptr(1), uintptr(_RP_FORCE)) err := createFakeGPKey() if err != nil { t.Fatalf("Creating fake GP key: %v\n", err) } defer deleteFakeGPKey(t) runTest(t, false) } func TestManagerWindowsGPMove(t *testing.T) { if !isWindows10OrBetter() || !winutil.IsCurrentProcessElevated() { t.Skipf("test requires running as elevated user on Windows 10+") } checkGPNotificationsWork(t) logf := func(format string, args ...any) { t.Logf(format, args...) } fakeInterface, err := windows.GenerateGUID() if err != nil { t.Fatalf("windows.GenerateGUID: %v\n", err) } delIfKey, err := createFakeInterfaceKey(t, fakeInterface) if err != nil { t.Fatalf("createFakeInterfaceKey: %v\n", err) } defer delIfKey() cfg, err := NewOSConfigurator(logf, fakeInterface.String()) if err != nil { t.Fatalf("NewOSConfigurator: %v\n", err) } mgr := cfg.(windowsManager) defer mgr.Close() usingGP := mgr.nrptDB.writeAsGP if usingGP { t.Fatalf("usingGP %v, want %v\n", usingGP, false) } regWatcher, err := newRegKeyWatcher() if err != nil { t.Fatalf("newRegKeyWatcher error %v\n", err) } // Upon initialization of cfg, we should not have any NRPT rules ensureNoRules(t) resolvers := []netip.Addr{netip.MustParseAddr("1.1.1.1")} domains := genRandomSubdomains(t, 1) // 1. Populate local NRPT err = mgr.setSplitDNS(resolvers, domains) if err != nil { t.Fatalf("setSplitDNS: %v\n", err) } t.Logf("Validating that local NRPT is populated...\n") validateRegistry(t, nrptBaseLocal, domains) ensureNoRulesInSubkey(t, nrptBaseGP) // 2. Create fake GP key and refresh t.Logf("Creating fake group policy key and refreshing...\n") err = createFakeGPKey() if err != nil { t.Fatalf("createFakeGPKey: %v\n", err) } err = regWatcher.watch() if err != nil { t.Fatalf("regWatcher.watch: %v\n", err) } err = testDoRefresh() if err != nil { t.Fatalf("testDoRefresh: %v\n", err) } err = regWatcher.wait() if err != nil { t.Fatalf("regWatcher.wait: %v\n", err) } // 3. Check that local NRPT is empty and GP is populated t.Logf("Validating that group policy NRPT is populated...\n") validateRegistry(t, nrptBaseGP, domains) ensureNoRulesInSubkey(t, nrptBaseLocal) // 4. Delete fake GP key and refresh t.Logf("Deleting fake group policy key and refreshing...\n") deleteFakeGPKey(t) err = regWatcher.watch() if err != nil { t.Fatalf("regWatcher.watch: %v\n", err) } err = testDoRefresh() if err != nil { t.Fatalf("testDoRefresh: %v\n", err) } err = regWatcher.wait() if err != nil { t.Fatalf("regWatcher.wait: %v\n", err) } // 5. Check that local NRPT is populated and GP is empty t.Logf("Validating that local NRPT is populated...\n") validateRegistry(t, nrptBaseLocal, domains) ensureNoRulesInSubkey(t, nrptBaseGP) // 6. Cleanup t.Logf("Cleaning up...\n") err = mgr.setSplitDNS(nil, domains) if err != nil { t.Fatalf("setSplitDNS: %v\n", err) } ensureNoRules(t) } func checkGPNotificationsWork(t *testing.T) { // Test to ensure that RegisterGPNotification work on this machine, // otherwise this test will fail. trk, err := newGPNotificationTracker() if err != nil { t.Skipf("newGPNotificationTracker error: %v\n", err) } defer trk.Close() r, _, err := procRefreshPolicyEx.Call(uintptr(1), uintptr(_RP_FORCE)) if r == 0 { t.Fatalf("RefreshPolicyEx error: %v\n", err) } timeout := uint32(10000) // Milliseconds if !trk.DidRefreshTimeout(timeout) { t.Skipf("GP notifications are not working on this machine\n") } } func runTest(t *testing.T, isLocal bool) { logf := func(format string, args ...any) { t.Logf(format, args...) } fakeInterface, err := windows.GenerateGUID() if err != nil { t.Fatalf("windows.GenerateGUID: %v\n", err) } delIfKey, err := createFakeInterfaceKey(t, fakeInterface) if err != nil { t.Fatalf("createFakeInterfaceKey: %v\n", err) } defer delIfKey() cfg, err := NewOSConfigurator(logf, fakeInterface.String()) if err != nil { t.Fatalf("NewOSConfigurator: %v\n", err) } mgr := cfg.(windowsManager) defer mgr.Close() usingGP := mgr.nrptDB.writeAsGP if isLocal == usingGP { t.Fatalf("usingGP %v, want %v\n", usingGP, !usingGP) } // Upon initialization of cfg, we should not have any NRPT rules ensureNoRules(t) resolvers := []netip.Addr{netip.MustParseAddr("1.1.1.1")} domains := genRandomSubdomains(t, 2*nrptMaxDomainsPerRule+1) cases := []int{ 1, 50, 51, 100, 101, 100, 50, 1, 51, } var regBaseValidate string var regBaseEnsure string if isLocal { regBaseValidate = nrptBaseLocal regBaseEnsure = nrptBaseGP } else { regBaseValidate = nrptBaseGP regBaseEnsure = nrptBaseLocal } var trk *gpNotificationTracker if isLocal { // (dblohm7) When isLocal == true, we keep trk active through the entire // sequence of test cases, and then we verify that no policy notifications // occurred. Because policy notifications are scoped to the entire computer, // this check could potentially fail if another process concurrently modifies // group policies while this test is running. I don't expect this to be an // issue on any computer on which we run this test, but something to keep in // mind if we start seeing flakiness around these GP notifications. trk, err = newGPNotificationTracker() if err != nil { t.Fatalf("newGPNotificationTracker: %v\n", err) } defer trk.Close() } runCase := func(n int) { t.Logf("Test case: %d domains\n", n) if !isLocal { // When !isLocal, we want to check that a GP notification occurred for // every single test case. trk, err = newGPNotificationTracker() if err != nil { t.Fatalf("newGPNotificationTracker: %v\n", err) } defer trk.Close() } caseDomains := domains[:n] err = mgr.setSplitDNS(resolvers, caseDomains) if err != nil { t.Fatalf("setSplitDNS: %v\n", err) } validateRegistry(t, regBaseValidate, caseDomains) ensureNoRulesInSubkey(t, regBaseEnsure) if !isLocal && !trk.DidRefresh(true) { t.Fatalf("DidRefresh false, want true\n") } } for _, n := range cases { runCase(n) } if isLocal && trk.DidRefresh(false) { t.Errorf("DidRefresh true, want false\n") } t.Logf("Test case: nil resolver\n") err = mgr.setSplitDNS(nil, domains) if err != nil { t.Fatalf("setSplitDNS: %v\n", err) } ensureNoRules(t) } func createFakeGPKey() error { keyStr := nrptBaseGP + `\` + testGPRuleID key, _, err := registry.CreateKey(registry.LOCAL_MACHINE, keyStr, registry.SET_VALUE) if err != nil { return fmt.Errorf("opening %s: %w", keyStr, err) } defer key.Close() if err := key.SetDWordValue("Version", 1); err != nil { return err } if err := key.SetStringsValue("Name", []string{"._setbygp_.example.com"}); err != nil { return err } if err := key.SetStringValue("GenericDNSServers", "1.1.1.1"); err != nil { return err } if err := key.SetDWordValue("ConfigOptions", nrptOverrideDNS); err != nil { return err } return nil } func deleteFakeGPKey(t *testing.T) { keyName := nrptBaseGP + `\` + testGPRuleID if err := registry.DeleteKey(registry.LOCAL_MACHINE, keyName); err != nil && err != registry.ErrNotExist { t.Fatalf("Error deleting NRPT rule key %q: %v\n", keyName, err) } isEmpty, err := isPolicyConfigSubkeyEmpty() if err != nil { t.Fatalf("isPolicyConfigSubkeyEmpty: %v", err) } if !isEmpty { return } if err := registry.DeleteKey(registry.LOCAL_MACHINE, nrptBaseGP); err != nil { t.Fatalf("Deleting DnsPolicyKey Subkey: %v", err) } } func createFakeInterfaceKey(t *testing.T, guid windows.GUID) (func(), error) { basePaths := []winutil.RegistryPathPrefix{winutil.IPv4TCPIPInterfacePrefix, winutil.IPv6TCPIPInterfacePrefix} keyPaths := make([]string, 0, len(basePaths)) guidStr := guid.String() for _, basePath := range basePaths { keyPath := string(basePath.WithSuffix(guidStr)) key, _, err := registry.CreateKey(registry.LOCAL_MACHINE, keyPath, registry.SET_VALUE) if err != nil { return nil, err } key.Close() keyPaths = append(keyPaths, keyPath) } result := func() { for _, keyPath := range keyPaths { if err := registry.DeleteKey(registry.LOCAL_MACHINE, keyPath); err != nil { t.Fatalf("deleting fake interface key \"%s\": %v\n", keyPath, err) } } } return result, nil } func ensureNoRules(t *testing.T) { ruleIDs := winutil.GetRegStrings(nrptRuleIDValueName, nil) if ruleIDs != nil { t.Errorf("%s: %v, want nil\n", nrptRuleIDValueName, ruleIDs) } for _, base := range []string{nrptBaseLocal, nrptBaseGP} { ensureNoSingleRule(t, base) } } func ensureNoRulesInSubkey(t *testing.T, base string) { ruleIDs := winutil.GetRegStrings(nrptRuleIDValueName, nil) if ruleIDs == nil { for _, base := range []string{nrptBaseLocal, nrptBaseGP} { ensureNoSingleRule(t, base) } return } for _, ruleID := range ruleIDs { keyName := base + `\` + ruleID key, err := registry.OpenKey(registry.LOCAL_MACHINE, keyName, registry.READ) if err == nil { key.Close() } else if err != registry.ErrNotExist { t.Fatalf("%s: %q, want %q\n", keyName, err, registry.ErrNotExist) } } if base == nrptBaseGP { // When dealing with the group policy subkey, we want the base key to // also be absent. key, err := registry.OpenKey(registry.LOCAL_MACHINE, base, registry.READ) if err == nil { key.Close() isEmpty, err := isPolicyConfigSubkeyEmpty() if err != nil { t.Fatalf("isPolicyConfigSubkeyEmpty: %v", err) } if isEmpty { t.Errorf("Unexpectedly found group policy key\n") } } else if err != registry.ErrNotExist { t.Errorf("Group policy key error: %q, want %q\n", err, registry.ErrNotExist) } } } func ensureNoSingleRule(t *testing.T, base string) { singleKeyPath := base + `\` + nrptSingleRuleID key, err := registry.OpenKey(registry.LOCAL_MACHINE, singleKeyPath, registry.READ) if err == nil { key.Close() } if err != registry.ErrNotExist { t.Fatalf("%s: %q, want %q\n", singleKeyPath, err, registry.ErrNotExist) } } func validateRegistry(t *testing.T, nrptBase string, domains []dnsname.FQDN) { q := len(domains) / nrptMaxDomainsPerRule r := len(domains) % nrptMaxDomainsPerRule numRules := q if r > 0 { numRules++ } ruleIDs := winutil.GetRegStrings(nrptRuleIDValueName, nil) if ruleIDs == nil { ruleIDs = []string{nrptSingleRuleID} } else if len(ruleIDs) != numRules { t.Errorf("%s for %d domains: %d, want %d\n", nrptRuleIDValueName, len(domains), len(ruleIDs), numRules) } for i, ruleID := range ruleIDs { savedDomains, err := getSavedDomainsForRule(nrptBase, ruleID) if err != nil { t.Fatalf("getSavedDomainsForRule(%q, %q): %v\n", nrptBase, ruleID, err) } start := i * nrptMaxDomainsPerRule end := start + nrptMaxDomainsPerRule if i == len(ruleIDs)-1 && r > 0 { end = start + r } checkDomains := domains[start:end] if len(checkDomains) != len(savedDomains) { t.Errorf("len(checkDomains) != len(savedDomains): %d, want %d\n", len(savedDomains), len(checkDomains)) } for j, cd := range checkDomains { sd := strings.TrimPrefix(savedDomains[j], ".") if string(cd.WithoutTrailingDot()) != sd { t.Errorf("checkDomain differs savedDomain: %s, want %s\n", sd, cd.WithoutTrailingDot()) } } } } func getSavedDomainsForRule(base, ruleID string) ([]string, error) { keyPath := base + `\` + ruleID key, err := registry.OpenKey(registry.LOCAL_MACHINE, keyPath, registry.READ) if err != nil { return nil, err } defer key.Close() result, _, err := key.GetStringsValue("Name") return result, err } func genRandomSubdomains(t *testing.T, n int) []dnsname.FQDN { domains := make([]dnsname.FQDN, 0, n) seed := time.Now().UnixNano() t.Logf("genRandomSubdomains(%d) seed: %v\n", n, seed) r := rand.New(rand.NewSource(seed)) const charset = "abcdefghijklmnopqrstuvwxyz" for len(domains) < cap(domains) { l := r.Intn(19) + 1 b := make([]byte, l) for i, _ := range b { b[i] = charset[r.Intn(len(charset))] } d := string(b) + ".example.com" fqdn, err := dnsname.ToFQDN(d) if err != nil { t.Fatalf("dnsname.ToFQDN: %v\n", err) } domains = append(domains, fqdn) } return domains } func testDoRefresh() (err error) { r, _, e := procRefreshPolicyEx.Call(uintptr(1), uintptr(_RP_FORCE)) if r == 0 { err = e } return err } // gpNotificationTracker registers with the Windows policy engine and receives // notifications when policy refreshes occur. type gpNotificationTracker struct { event windows.Handle } func newGPNotificationTracker() (*gpNotificationTracker, error) { var err error evt, err := windows.CreateEvent(nil, 0, 0, nil) if err != nil { return nil, err } defer func() { if err != nil { windows.CloseHandle(evt) } }() ok, _, e := procRegisterGPNotification.Call( uintptr(evt), uintptr(1), // We want computer policy changes, not user policy changes. ) if ok == 0 { err = e return nil, err } return &gpNotificationTracker{evt}, nil } func (trk *gpNotificationTracker) DidRefresh(isExpected bool) bool { // If we're not expecting a refresh event, then we need to use a timeout. timeout := uint32(1000) // 1 second (in milliseconds) if isExpected { // Otherwise, since it is imperative that we see an event, we wait infinitely. timeout = windows.INFINITE } return trk.DidRefreshTimeout(timeout) } func (trk *gpNotificationTracker) DidRefreshTimeout(timeout uint32) bool { waitCode, _ := windows.WaitForSingleObject(trk.event, timeout) return waitCode == windows.WAIT_OBJECT_0 } func (trk *gpNotificationTracker) Close() error { procUnregisterGPNotification.Call(uintptr(trk.event)) windows.CloseHandle(trk.event) trk.event = 0 return nil } type regKeyWatcher struct { keyLocal registry.Key keyGP registry.Key evtLocal windows.Handle evtGP windows.Handle } func newRegKeyWatcher() (*regKeyWatcher, error) { var err error keyLocal, _, err := registry.CreateKey(registry.LOCAL_MACHINE, nrptBaseLocal, registry.READ) if err != nil { return nil, err } defer func() { if err != nil { keyLocal.Close() } }() // Monitor dnsBaseGP instead of nrptBaseGP, since the latter will be // repeatedly created and destroyed throughout the course of the test. keyGP, _, err := registry.CreateKey(registry.LOCAL_MACHINE, dnsBaseGP, registry.READ) if err != nil { return nil, err } defer func() { if err != nil { keyGP.Close() } }() evtLocal, err := windows.CreateEvent(nil, 0, 0, nil) if err != nil { return nil, err } defer func() { if err != nil { windows.CloseHandle(evtLocal) } }() evtGP, err := windows.CreateEvent(nil, 0, 0, nil) if err != nil { return nil, err } result := ®KeyWatcher{ keyLocal: keyLocal, keyGP: keyGP, evtLocal: evtLocal, evtGP: evtGP, } return result, nil } func (rw *regKeyWatcher) watch() error { // We can make these waits thread-agnostic because the tests that use this code must already run on Windows 10+ err := windows.RegNotifyChangeKeyValue(windows.Handle(rw.keyLocal), true, windows.REG_NOTIFY_CHANGE_NAME|windows.REG_NOTIFY_THREAD_AGNOSTIC, rw.evtLocal, true) if err != nil { return err } return windows.RegNotifyChangeKeyValue(windows.Handle(rw.keyGP), true, windows.REG_NOTIFY_CHANGE_NAME|windows.REG_NOTIFY_THREAD_AGNOSTIC, rw.evtGP, true) } func (rw *regKeyWatcher) wait() error { handles := []windows.Handle{ rw.evtLocal, rw.evtGP, } waitCode, err := windows.WaitForMultipleObjects( handles, true, // Wait for both events to signal before resuming. 10000, // 10 seconds (as milliseconds) ) const WAIT_TIMEOUT = 0x102 switch waitCode { case WAIT_TIMEOUT: return context.DeadlineExceeded case windows.WAIT_FAILED: return err default: return nil } } func (rw *regKeyWatcher) Close() error { rw.keyLocal.Close() rw.keyGP.Close() windows.CloseHandle(rw.evtLocal) windows.CloseHandle(rw.evtGP) return nil }