Initial commit

COPYING

+Copyright (c) 2017 Autistici/Inventati <info@autistici.org>
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.

client/client.go

+package client
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"net/textproto"
+
+	"git.autistici.org/id/auth"
+)
+
+var defaultSocket = "/run/auth/socket"
+
+type Client struct {
+	socketPath string
+	codec      auth.Codec
+}
+
+func New(socketPath string) *Client {
+	return &Client{
+		socketPath: socketPath,
+		codec:      auth.DefaultCodec,
+	}
+}
+
+func (c *Client) Authenticate(ctx context.Context, req *auth.Request) (*auth.Response, error) {
+	conn, err := textproto.Dial("unix", c.socketPath)
+	if err != nil {
+		return nil, err
+	}
+	defer conn.Close()
+
+	var resp auth.Response
+	done := make(chan error)
+
+	go func() {
+		defer close(done)
+
+		// Write the command to a buffer.
+		var buf bytes.Buffer
+		io.WriteString(&buf, "auth ")
+		buf.Write(c.codec.Encode(req))
+		if err := conn.PrintfLine(buf.String()); err != nil {
+			done <- err
+			return
+		}
+
+		// Read the response.
+		line, err := conn.ReadLineBytes()
+		if err != nil {
+			done <- err
+			return
+		}
+		if err := c.codec.Decode(line, &resp); err != nil {
+			done <- err
+			return
+		}
+		done <- nil
+	}()
+
+	// Wait for the call to terminate, or the context to time out,
+	// whichever happens first.
+	select {
+	case err := <-done:
+		return &resp, err
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+}

cmd/authserver/main.go

+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"git.autistici.org/id/auth/server"
+	"github.com/coreos/go-systemd/daemon"
+)
+
+var (
+	configPath              = flag.String("config", "/etc/authserver/config.yml", "configuration `file`")
+	socketPath              = flag.String("socket", "/run/auth/socket", "`path` to the UNIX socket to listen on")
+	systemdSocketActivation = flag.Bool("systemd-socket", false, "use SystemD socket activation")
+)
+
+func usage() {
+	fmt.Fprintf(os.Stderr, `authserv - a simple authentication server
+Usage: authserv [<OPTIONS>]
+
+Known options:
+`)
+	flag.PrintDefaults()
+}
+
+func main() {
+	log.SetFlags(0)
+	flag.Usage = usage
+	flag.Parse()
+
+	syscall.Umask(007)
+
+	config, err := server.LoadConfig(*configPath)
+	if err != nil {
+		log.Fatalf("could not load configuration: %v", err)
+	}
+
+	authSrv, err := server.NewServer(config, nil)
+	if err != nil {
+		log.Fatalf("configuration error: %v", err)
+	}
+
+	var sockSrv *server.SocketServer
+	if *systemdSocketActivation {
+		sockSrv, err = server.NewSystemdSocketServer(authSrv)
+	} else {
+		sockSrv, err = server.NewSocketServer(*socketPath, authSrv)
+	}
+	if err != nil {
+		log.Fatalf("error: %v", err)
+	}
+
+	sigCh := make(chan os.Signal, 1)
+	go func() {
+		<-sigCh
+		log.Printf("terminating")
+		sockSrv.Close()
+	}()
+	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
+
+	log.Printf("starting")
+	daemon.SdNotify(false, "READY=1")
+	sockSrv.Serve()
+}

codec.go

+package auth
+
+import (
+	"bytes"
+	"encoding/base64"
+	"fmt"
+	"io"
+)
+
+// Codec serializes simple key/value maps on the wire. Requirements
+// for a codec: it must transfer maps, it must be trivial to implement
+// in both C, Go and Python. It must not have messy external
+// dependencies if possible.
+type Codec interface {
+	Encode(interface{}) []byte
+	Decode([]byte, interface{}) error
+}
+
+type mapEncodable interface {
+	EncodeToMap(map[string]string, string)
+}
+
+type mapDecodable interface {
+	DecodeFromMap(map[string]string, string)
+}
+
+type kvCodec struct{}
+
+var DefaultCodec = &kvCodec{}
+
+//var charsToEscape = "\" \r\n"
+
+func shouldEscapeString(s string) bool {
+	for _, r := range s {
+		if r < 32 || r > 127 || r == '"' || r == ' ' || r == '\r' || r == '\n' {
+			return true
+		}
+	}
+	return false
+}
+
+func (c kvCodec) encodeMap(obj map[string]string) []byte {
+	var buf bytes.Buffer
+	first := true
+	for key, value := range obj {
+		if first {
+			first = false
+		} else {
+			io.WriteString(&buf, " ")
+		}
+		fmt.Fprintf(&buf, "%s=", key)
+		if shouldEscapeString(value) {
+			w := base64.NewEncoder(base64.RawURLEncoding, &buf)
+			io.WriteString(w, value)
+			w.Close()
+		} else {
+			fmt.Fprintf(&buf, "\"%s\"", value)
+		}
+	}
+	return buf.Bytes()
+}
+
+func (c kvCodec) Encode(obj interface{}) []byte {
+	var m map[string]string
+	switch t := obj.(type) {
+	case map[string]string:
+		m = t
+	case mapEncodable:
+		m = make(map[string]string)
+		t.EncodeToMap(m, "")
+	default:
+		// TODO: Error
+	}
+	return c.encodeMap(m)
+}
+
+type inputScanner struct {
+	b   []byte
+	pos int
+}
+
+func (i *inputScanner) next() (byte, bool) {
+	if i.pos >= len(i.b) {
+		return 0, true
+	}
+	value := i.b[i.pos]
+	i.pos++
+	return value, false
+}
+
+func (i *inputScanner) ungetc() {
+	if i.pos > 0 {
+		i.pos--
+	}
+}
+
+func (i *inputScanner) skipWhitespace() {
+	for {
+		c, eof := i.next()
+		if eof {
+			return
+		}
+		if c != ' ' {
+			break
+		}
+	}
+	i.ungetc()
+}
+
+func (i *inputScanner) parseUntil(sep byte) ([]byte, error) {
+	pos := i.pos
+	idx := bytes.IndexByte(i.b[pos:], sep)
+	if idx == -1 {
+		return nil, io.EOF
+	}
+	value := i.b[i.pos : i.pos+idx]
+	i.pos += idx + 1
+	return value, nil
+}
+
+func (i *inputScanner) parseUntilOrEOF(sep byte) []byte {
+	pos := i.pos
+	idx := bytes.IndexByte(i.b[pos:], sep)
+	if idx == -1 {
+		i.pos = len(i.b)
+	} else {
+		i.pos = pos + idx
+	}
+	return i.b[pos:i.pos]
+}
+
+func (i *inputScanner) parseKey() (string, error) {
+	i.skipWhitespace()
+	key, err := i.parseUntil('=')
+	if err != nil {
+		return "", err
+	}
+	return string(key), nil
+}
+
+func (i *inputScanner) parseQuotedString() (string, error) {
+	s, err := i.parseUntil('"')
+	if err != nil {
+		return "", err
+	}
+	return string(s), nil
+}
+
+func (i *inputScanner) parseBase64String() (string, error) {
+	data := i.parseUntilOrEOF(' ')
+	out := make([]byte, base64.RawURLEncoding.DecodedLen(len(data)))
+	_, err := base64.RawURLEncoding.Decode(out, data)
+	if err != nil {
+		return "", err
+	}
+	return string(out), nil
+}
+
+func (i *inputScanner) parseValue() (string, error) {
+	c, eof := i.next()
+	if eof {
+		return "", io.EOF
+	}
+	if c == '"' {
+		return i.parseQuotedString()
+	}
+	i.ungetc()
+	return i.parseBase64String()
+}
+
+func (i *inputScanner) parseAssignment() (string, string, error) {
+	key, err := i.parseKey()
+	if err == io.EOF {
+		return "", "", nil
+	} else if err != nil {
+		return "", "", err
+	}
+	value, err := i.parseValue()
+	if err != nil {
+		return "", "", err
+	}
+	return key, value, nil
+}
+
+func (c kvCodec) decodeMap(b []byte, out map[string]string) (map[string]string, error) {
+	if out == nil {
+		out = make(map[string]string)
+	}
+	i := &inputScanner{b: b}
+	for {
+		key, value, err := i.parseAssignment()
+		if err != nil {
+			return nil, err
+		}
+		if key == "" {
+			break
+		}
+		out[key] = value
+	}
+	return out, nil
+}
+
+func (c kvCodec) Decode(b []byte, obj interface{}) error {
+	var m map[string]string
+	switch t := obj.(type) {
+	case map[string]string:
+		m = t
+	}
+	var err error
+	m, err = c.decodeMap(b, m)
+	if err != nil {
+		return err
+	}
+	switch t := obj.(type) {
+	case mapDecodable:
+		t.DecodeFromMap(m, "")
+	}
+	return nil
+}

codec_test.go

+package auth
+
+import (
+	"bytes"
+	"fmt"
+	"math/rand"
+	"reflect"
+	"testing"
+)
+
+func makeRandomString(n int) string {
+	var buf bytes.Buffer
+	for i := 0; i < n; i++ {
+		c := byte(rand.Intn(254) + 1)
+		buf.Write([]byte{c})
+	}
+	return buf.String()
+}
+
+func makeRandomMap() map[string]string {
+	m := make(map[string]string)
+	for i := 0; i < 7; i++ {
+		var value string
+		n := rand.Intn(10)
+		switch {
+		case n < 3:
+			value = "asdf \""
+		case n < 5:
+			value = makeRandomString(64)
+		default:
+			value = fmt.Sprintf("value%d", i+1)
+		}
+		m[fmt.Sprintf("key%d", i+1)] = value
+	}
+	return m
+}
+
+func TestCodec_UTF8(t *testing.T) {
+	c := &kvCodec{}
+	m := map[string]string{
+		"hello": "Hello, 世界",
+	}
+	b := c.Encode(m)
+	m2 := make(map[string]string)
+	err := c.Decode(b, m2)
+	if err != nil {
+		t.Fatal("Decode():", err)
+	}
+	if !reflect.DeepEqual(m, m2) {
+		t.Fatalf("results differ: %+v vs %+v", m, m2)
+	}
+}
+
+func TestCodec_Random(t *testing.T) {
+	c := &kvCodec{}
+
+	for i := 0; i < 1000; i++ {
+		m := makeRandomMap()
+		b := c.Encode(m)
+		//t.Logf("encoded: '%s'", string(b))
+
+		m2 := make(map[string]string)
+		err := c.Decode(b, m2)
+		if err != nil {
+			t.Fatalf("Decode(%s): %v", string(b), err)
+		}
+		if !reflect.DeepEqual(m, m2) {
+			t.Fatalf("decode results differ: %+v vs %+v", m, m2)
+		}
+	}
+}

protocol.go

+package auth
+
+import (
+	"fmt"
+
+	"github.com/tstranex/u2f"
+)
+
+// DeviceInfo holds information about the client device. We use a
+// simple persistent cookie to track the same client device across
+// multiple session.
+type DeviceInfo struct {
+	ID         string
+	RemoteAddr string
+	RemoteZone string
+	Browser    string
+	OS         string
+}
+
+func (d *DeviceInfo) encodeToMap(m map[string]string, prefix string) {
+	m[prefix+"id"] = d.ID
+	m[prefix+"remote_addr"] = d.RemoteAddr
+	m[prefix+"remote_zone"] = d.RemoteZone
+	m[prefix+"browser"] = d.Browser
+	m[prefix+"os"] = d.OS
+}
+
+func decodeDeviceInfoFromMap(m map[string]string, prefix string) *DeviceInfo {
+	if _, ok := m[prefix+"id"]; !ok {
+		return nil
+	}
+	return &DeviceInfo{
+		ID:         m[prefix+"id"],
+		RemoteAddr: m[prefix+"remote_addr"],
+		RemoteZone: m[prefix+"remote_zone"],
+		Browser:    m[prefix+"browser"],
+		OS:         m[prefix+"os"],
+	}
+}
+
+// Request to authenticate a user. It supports multiple methods for
+// authentication including challenge-response 2FA.
+type Request struct {
+	Service     string
+	Username    string
+	Password    []byte
+	OTP         string
+	U2FAppID    string
+	U2FResponse *u2f.SignResponse
+	DeviceInfo  *DeviceInfo
+	//Extra       map[string]string
+}
+
+func (r *Request) EncodeToMap(m map[string]string, prefix string) {
+	m[prefix+"service"] = r.Service
+	m[prefix+"username"] = r.Username
+	m[prefix+"password"] = string(r.Password)
+
+	if r.OTP != "" {
+		m[prefix+"otp"] = r.OTP
+	}
+	if r.U2FAppID != "" {
+		m[prefix+"u2f_app_id"] = r.U2FAppID
+	}
+	if r.U2FResponse != nil {
+		encodeU2FResponseToMap(r.U2FResponse, m, prefix+"u2f_response.")
+	}
+	if r.DeviceInfo != nil {
+		r.DeviceInfo.encodeToMap(m, prefix+"device.")
+	}
+}
+
+func (r *Request) DecodeFromMap(m map[string]string, prefix string) {
+	r.Service = m[prefix+"service"]
+	r.Username = m[prefix+"username"]
+	r.Password = []byte(m[prefix+"password"])
+	r.OTP = m[prefix+"otp"]
+	r.U2FAppID = m[prefix+"u2f_app_id"]
+	r.U2FResponse = decodeU2FResponseFromMap(m, prefix+"u2f_response.")
+	r.DeviceInfo = decodeDeviceInfoFromMap(m, prefix+"device.")
+}
+
+// UserInfo contains optional user information.
+type UserInfo struct {
+	Email  string
+	Groups []string
+}
+
+func (u *UserInfo) EncodeToMap(m map[string]string, prefix string) {
+	if u.Email != "" {
+		m[prefix+"email"] = u.Email
+	}
+	for i, g := range u.Groups {
+		m[fmt.Sprintf("%sgroup.%d.", prefix, i)] = g
+	}
+}
+
+func decodeUserInfoFromMap(m map[string]string, prefix string) *UserInfo {
+	u := UserInfo{Email: m[prefix+"email"]}
+	i := 0
+	for {
+		s, ok := m[fmt.Sprintf("%sgroup.%d.", prefix, i)]
+		if !ok {
+			break
+		}
+		u.Groups = append(u.Groups, s)
+		i++
+	}
+	if u.Email == "" && len(u.Groups) == 0 {
+		return nil
+	}
+	return &u
+}
+
+// Response to an authentication request.
+type Response struct {
+	Status         Status
+	TFAMethod      TFAMethod
+	U2FSignRequest *u2f.WebSignRequest
+	UserInfo       *UserInfo
+}
+
+func (r *Response) EncodeToMap(m map[string]string, prefix string) {
+	m[prefix+"status"] = r.Status.String()
+	m[prefix+"2fa_method"] = string(r.TFAMethod)
+	if r.U2FSignRequest != nil {
+		// External type.
+		encodeU2FSignRequestToMap(r.U2FSignRequest, m, prefix+"u2f_req.")
+	}
+	if r.UserInfo != nil {
+		r.UserInfo.EncodeToMap(m, prefix+"user.")
+	}
+}
+
+func (r *Response) DecodeFromMap(m map[string]string, prefix string) {
+	r.Status = parseAuthStatus(m[prefix+"status"])
+	r.TFAMethod = TFAMethod(m[prefix+"2fa_method"])
+	r.U2FSignRequest = decodeU2FSignRequestFromMap(m, prefix+"u2f_req.")
+	r.UserInfo = decodeUserInfoFromMap(m, prefix+"user.")
+}
+
+// TFAMethod is a hint provided to the caller with the type of 2FA
+// method that is available for authentication.
+type TFAMethod string
+
+const (
+	TFAMethodNone = ""
+	TFAMethodOTP  = "otp"
+	TFAMethodU2F  = "u2f"
+)
+
+// Status of an authentication request.
+type Status int
+
+const (
+	StatusOK = iota
+	StatusInsufficientCredentials
+	StatusError
+)
+
+func (s Status) String() string {
+	switch s {
+	case StatusOK:
+		return "ok"
+	case StatusInsufficientCredentials:
+		return "insufficient_credentials"
+	case StatusError:
+		return "error"
+	default:
+		return fmt.Sprintf("unknown(%d)", int(s))
+	}
+}
+
+func parseAuthStatus(s string) Status {
+	switch s {
+	case "ok":
+		return StatusOK
+	case "insufficient_credentials":
+		return StatusInsufficientCredentials
+	default:
+		return StatusError
+	}
+}
+
+func (s Status) Error() string {
+	return s.String()
+}
+
+// Miscellaneous serializers for external objects.
+
+func encodeU2FResponseToMap(resp *u2f.SignResponse, m map[string]string, prefix string) {
+	m[prefix+"key_handle"] = resp.KeyHandle
+	m[prefix+"signature_data"] = resp.SignatureData
+	m[prefix+"client_data"] = resp.ClientData
+}
+
+func decodeU2FResponseFromMap(m map[string]string, prefix string) *u2f.SignResponse {
+	if _, ok := m[prefix+"key_handle"]; !ok {
+		return nil
+	}
+	return &u2f.SignResponse{