+ "--glinet" command-line argument: Run in GL-Inet compatibility mode

Close #1853

Squashed commit of the following:

commit 3730cafabe8fa1dbf2bf75915079d2effe4ff9a3
Merge: 533ae3c2 6b134469
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Jul 3 19:21:08 2020 +0300

    Merge remote-tracking branch 'origin/master' into 1853-glinet

commit 533ae3c2678cd6cfd26bf9560bee4eb5a015a615
Merge: 3521992b 21dfb5ff
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Jul 3 19:14:45 2020 +0300

    Merge remote-tracking branch 'origin/master' into 1853-glinet

commit 3521992b4609fa3400942c89f7a7546dade459bc
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Jul 3 18:04:53 2020 +0300

    logs

commit 3e0258782b1a14c08156fe65940ae7b661a42b54
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Jul 3 17:11:47 2020 +0300

    fix

commit bb814db9df1c770d0ea02eafd12bedd122bef894
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Jul 3 16:58:37 2020 +0300

    minor

commit b161bbc5749ce76b16600e0153120935ad20077e
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Fri Jul 3 16:53:22 2020 +0300

    move code

commit c506e81265bdee140c0f61255f927c13738efc1a
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Jul 2 10:50:56 2020 +0300

    test

commit c09f201cbd88498a2328be332197e4d96e5fb115
Author: Simon Zolin <s.zolin@adguard.com>
Date:   Thu Jul 2 10:42:23 2020 +0300

    + "--glinet" command-line argument: Run in GL-Inet compatibility mode

home/auth.go

@@ -365,6 +365,7 @@ func parseCookie(cookie string) string {
 	return ""
 }
 
+// nolint(gocyclo)
 func optionalAuth(handler func(http.ResponseWriter, *http.Request)) func(http.ResponseWriter, *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {
 
@@ -391,7 +392,11 @@ func optionalAuth(handler func(http.ResponseWriter, *http.Request)) func(http.Re
 			// redirect to login page if not authenticated
 			ok := false
 			cookie, err := r.Cookie(sessionCookieName)
-			if err == nil {
+
+			if glProcessCookie(r) {
+				log.Debug("Auth: authentification was handled by GL-Inet submodule")
+
+			} else if err == nil {
 				r := Context.auth.CheckSession(cookie.Value)
 				if r == 0 {
 					ok = true
@@ -412,8 +417,13 @@ func optionalAuth(handler func(http.ResponseWriter, *http.Request)) func(http.Re
 			}
 			if !ok {
 				if r.URL.Path == "/" || r.URL.Path == "/index.html" {
-					w.Header().Set("Location", "/login.html")
-					w.WriteHeader(http.StatusFound)
+					if glProcessRedirect(w, r) {
+						log.Debug("Auth: redirected to login page by GL-Inet submodule")
+
+					} else {
+						w.Header().Set("Location", "/login.html")
+						w.WriteHeader(http.StatusFound)
+					}
 				} else {
 					w.WriteHeader(http.StatusForbidden)
 					_, _ = w.Write([]byte("Forbidden"))
@@ -510,6 +520,10 @@ func (a *Auth) GetUsers() []User {
 
 // AuthRequired - if authentication is required
 func (a *Auth) AuthRequired() bool {
+	if GLMode {
+		return true
+	}
+
 	a.lock.Lock()
 	r := (len(a.users) != 0)
 	a.lock.Unlock()

home/auth_glinet.go

@@ -0,0 +1,102 @@
+package home
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"os"
+	"time"
+	"unsafe"
+
+	"github.com/AdguardTeam/golibs/log"
+)
+
+// GLMode - enable GL-Inet compatibility mode
+var GLMode bool
+
+var glFilePrefix = "/tmp/gl_token_"
+
+const glTokenTimeoutSeconds = 3600
+const glCookieName = "Admin-Token"
+
+func glProcessRedirect(w http.ResponseWriter, r *http.Request) bool {
+	if !GLMode {
+		return false
+	}
+	// redirect to gl-inet login
+	host, _, _ := net.SplitHostPort(r.Host)
+	url := "http://" + host
+	log.Debug("Auth: redirecting to %s", url)
+	http.Redirect(w, r, url, http.StatusFound)
+	return true
+}
+
+func glProcessCookie(r *http.Request) bool {
+	if !GLMode {
+		return false
+	}
+
+	glCookie, glerr := r.Cookie(glCookieName)
+	if glerr != nil {
+		return false
+	}
+
+	log.Debug("Auth: GL cookie value: %s", glCookie.Value)
+	if glCheckToken(glCookie.Value) {
+		return true
+	}
+	log.Info("Auth: invalid GL cookie value: %s", glCookie)
+	return false
+}
+
+func glCheckToken(sess string) bool {
+	tokenName := glFilePrefix + sess
+	_, err := os.Stat(tokenName)
+	if err != nil {
+		log.Error("os.Stat: %s", err)
+		return false
+	}
+	tokenDate := glGetTokenDate(tokenName)
+	now := uint32(time.Now().UTC().Unix())
+	return now <= (tokenDate + glTokenTimeoutSeconds)
+}
+
+func archIsLittleEndian() bool {
+	var i int32 = 0x01020304
+	u := unsafe.Pointer(&i)
+	pb := (*byte)(u)
+	b := *pb
+	return (b == 0x04)
+}
+
+func glGetTokenDate(file string) uint32 {
+	f, err := os.Open(file)
+	if err != nil {
+		log.Error("os.Open: %s", err)
+		return 0
+	}
+	var dateToken uint32
+	bs, err := ioutil.ReadAll(f)
+	if err != nil {
+		log.Error("ioutil.ReadAll: %s", err)
+		return 0
+	}
+	buf := bytes.NewBuffer(bs)
+
+	if archIsLittleEndian() {
+		err := binary.Read(buf, binary.LittleEndian, &dateToken)
+		if err != nil {
+			log.Error("binary.Read: %s", err)
+			return 0
+		}
+	} else {
+		err := binary.Read(buf, binary.BigEndian, &dateToken)
+		if err != nil {
+			log.Error("binary.Read: %s", err)
+			return 0
+		}
+	}
+	return dateToken
+}

home/auth_glinet_test.go

@@ -0,0 +1,43 @@
+package home
+
+import (
+	"encoding/binary"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAuthGL(t *testing.T) {
+	dir := prepareTestDir()
+	defer func() { _ = os.RemoveAll(dir) }()
+
+	GLMode = true
+	glFilePrefix = dir + "/gl_token_"
+
+	tval := uint32(1)
+	data := make([]byte, 4)
+	if archIsLittleEndian() {
+		binary.LittleEndian.PutUint32(data, tval)
+	} else {
+		binary.BigEndian.PutUint32(data, tval)
+	}
+	assert.Nil(t, ioutil.WriteFile(glFilePrefix+"test", data, 0644))
+	assert.False(t, glCheckToken("test"))
+
+	tval = uint32(time.Now().UTC().Unix() + 60)
+	data = make([]byte, 4)
+	if archIsLittleEndian() {
+		binary.LittleEndian.PutUint32(data, tval)
+	} else {
+		binary.BigEndian.PutUint32(data, tval)
+	}
+	assert.Nil(t, ioutil.WriteFile(glFilePrefix+"test", data, 0644))
+	r, _ := http.NewRequest("GET", "http://localhost/", nil)
+	r.AddCookie(&http.Cookie{Name: glCookieName, Value: "test"})
+	assert.True(t, glProcessCookie(r))
+	GLMode = false
+}

home/home.go

@@ -263,6 +263,7 @@ func run(args options) {
 	}
 
 	sessFilename := filepath.Join(Context.getDataDir(), "sessions.db")
+	GLMode = args.glinetMode
 	Context.auth = InitAuth(sessFilename, config.Users, config.WebSessionTTLHours*60*60)
 	if Context.auth == nil {
 		log.Fatalf("Couldn't initialize Auth module")
@@ -525,6 +526,8 @@ type options struct {
 
 	// runningAsService flag is set to true when options are passed from the service runner
 	runningAsService bool
+
+	glinetMode bool // Activate GL-Inet mode
 }
 
 // loadOptions reads command line arguments and initializes configuration
@@ -559,6 +562,7 @@ func loadOptions() options {
 		{"check-config", "", "Check configuration and exit", nil, func() { o.checkConfig = true }},
 		{"no-check-update", "", "Don't check for updates", nil, func() { o.disableUpdate = true }},
 		{"verbose", "v", "Enable verbose output", nil, func() { o.verbose = true }},
+		{"glinet", "", "Run in GL-Inet compatibility mode", nil, func() { o.glinetMode = true }},
 		{"version", "", "Show the version and exit", nil, func() {
 			fmt.Printf("AdGuardHome %s\n", versionString)
 			os.Exit(0)