forked from jshiffer/go-xmpp
add scram auth (#147)
* Fix syntax errors. * gofmt * Add SCRAM-SHA-1, SCRAM-SHA-256 and SCRAM-SHA-512 auth
This commit is contained in:
Martin
GitHub
parent
9129a110df
commit
bef3e549f7
288
xmpp.go
288
xmpp.go
@ -15,22 +15,30 @@ package xmpp
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import (
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"bufio"
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"bytes"
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"crypto/hmac"
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"crypto/md5"
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"crypto/rand"
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"crypto/sha1"
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"crypto/sha256"
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"crypto/sha512"
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"crypto/tls"
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"encoding/base64"
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"encoding/binary"
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"encoding/xml"
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"errors"
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"fmt"
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"hash"
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"io"
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"math/big"
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"net"
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"net/http"
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"net/url"
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"os"
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"strconv"
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"strings"
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"time"
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"golang.org/x/crypto/pbkdf2"
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)
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const (
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@ -364,7 +372,8 @@ func (c *Client) init(o *Options) error {
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if f, err = c.startTLSIfRequired(f, o, domain); err != nil {
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return err
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}
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var mechanism string
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var serverSignature []byte
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if o.User == "" && o.Password == "" {
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foundAnonymous := false
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for _, m := range f.Mechanisms.Mechanism {
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@ -385,77 +394,213 @@ func (c *Client) init(o *Options) error {
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return errors.New("refusing to authenticate over unencrypted TCP connection")
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}
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mechanism := ""
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mechanism = ""
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for _, m := range f.Mechanisms.Mechanism {
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if m == "X-OAUTH2" && o.OAuthToken != "" && o.OAuthScope != "" {
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switch m {
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case "SCRAM-SHA-512":
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mechanism = m
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// Oauth authentication: send base64-encoded \x00 user \x00 token.
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raw := "\x00" + user + "\x00" + o.OAuthToken
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enc := make([]byte, base64.StdEncoding.EncodedLen(len(raw)))
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base64.StdEncoding.Encode(enc, []byte(raw))
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fmt.Fprintf(c.conn, "<auth xmlns='%s' mechanism='X-OAUTH2' auth:service='oauth2' "+
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"xmlns:auth='%s'>%s</auth>\n", nsSASL, o.OAuthXmlNs, enc)
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break
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}
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if m == "PLAIN" {
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mechanism = m
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// Plain authentication: send base64-encoded \x00 user \x00 password.
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raw := "\x00" + user + "\x00" + o.Password
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enc := make([]byte, base64.StdEncoding.EncodedLen(len(raw)))
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base64.StdEncoding.Encode(enc, []byte(raw))
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fmt.Fprintf(c.conn, "<auth xmlns='%s' mechanism='PLAIN'>%s</auth>\n", nsSASL, enc)
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break
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}
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if m == "DIGEST-MD5" {
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mechanism = m
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// Digest-MD5 authentication
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fmt.Fprintf(c.conn, "<auth xmlns='%s' mechanism='DIGEST-MD5'/>\n", nsSASL)
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var ch saslChallenge
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if err = c.p.DecodeElement(&ch, nil); err != nil {
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return errors.New("unmarshal <challenge>: " + err.Error())
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case "SCRAM-SHA-256":
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if mechanism != "SCRAM-SHA-512" {
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mechanism = m
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}
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b, err := base64.StdEncoding.DecodeString(string(ch))
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if err != nil {
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return err
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case "SCRAM-SHA-1":
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if mechanism != "SCRAM-SHA-512" &&
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mechanism != "SCRAM-SHA-256" {
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mechanism = m
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}
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tokens := map[string]string{}
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for _, token := range strings.Split(string(b), ",") {
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kv := strings.SplitN(strings.TrimSpace(token), "=", 2)
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if len(kv) == 2 {
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if kv[1][0] == '"' && kv[1][len(kv[1])-1] == '"' {
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kv[1] = kv[1][1 : len(kv[1])-1]
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}
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tokens[kv[0]] = kv[1]
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case "X-OAUTH2":
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if mechanism == "" {
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mechanism = m
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}
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case "PLAIN":
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if mechanism == "" {
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mechanism = m
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}
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case "DIGEST-MD5":
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if mechanism == "" {
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mechanism = m
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}
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}
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}
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if strings.HasPrefix(mechanism, "SCRAM-SHA") {
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var shaNewFn func() hash.Hash
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switch mechanism {
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case "SCRAM-SHA-512":
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shaNewFn = sha512.New
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case "SCRAM-SHA-256":
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shaNewFn = sha256.New
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case "SCRAM-SHA-1":
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shaNewFn = sha1.New
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default:
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return errors.New("unsupported auth mechanism")
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}
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clientNonce := cnonce()
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clientFirstMessage := "n=" + user + ",r=" + clientNonce
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fmt.Fprintf(StanzaWriter, "<auth xmlns='%s' mechanism='%s'>%s</auth>",
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nsSASL, mechanism, base64.StdEncoding.EncodeToString([]byte("n,,"+
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clientFirstMessage)))
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var sfm string
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if err = c.p.DecodeElement(&sfm, nil); err != nil {
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return errors.New("unmarshal <challenge>: " + err.Error())
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}
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b, err := base64.StdEncoding.DecodeString(string(sfm))
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if err != nil {
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return err
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}
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var serverNonce string
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var salt []byte
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var iterations int
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for _, serverReply := range strings.Split(string(b), ",") {
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switch {
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case strings.HasPrefix(serverReply, "r="):
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serverNonce = strings.SplitN(serverReply, "=", 2)[1]
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if !strings.HasPrefix(serverNonce, clientNonce) {
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return errors.New("SCRAM: server nonce didn't start with client nonce")
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}
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case strings.HasPrefix(serverReply, "s="):
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salt, err = base64.StdEncoding.DecodeString(strings.SplitN(serverReply, "=", 2)[1])
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if string(salt) == "" {
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return errors.New("SCRAM: server sent empty salt")
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}
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case strings.HasPrefix(serverReply, "i="):
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iterations, err = strconv.Atoi(strings.SplitN(serverReply,
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"=", 2)[1])
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if err != nil {
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return err
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}
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default:
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return errors.New("unexpected conted in SCRAM challenge")
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}
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realm, _ := tokens["realm"]
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nonce, _ := tokens["nonce"]
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qop, _ := tokens["qop"]
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charset, _ := tokens["charset"]
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cnonceStr := cnonce()
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digestURI := "xmpp/" + domain
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nonceCount := fmt.Sprintf("%08x", 1)
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digest := saslDigestResponse(user, realm, o.Password, nonce, cnonceStr, "AUTHENTICATE", digestURI, nonceCount)
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message := "username=\"" + user + "\", realm=\"" + realm + "\", nonce=\"" + nonce + "\", cnonce=\"" + cnonceStr +
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"\", nc=" + nonceCount + ", qop=" + qop + ", digest-uri=\"" + digestURI + "\", response=" + digest + ", charset=" + charset
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fmt.Fprintf(c.conn, "<response xmlns='%s'>%s</response>\n", nsSASL, base64.StdEncoding.EncodeToString([]byte(message)))
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var rspauth saslRspAuth
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if err = c.p.DecodeElement(&rspauth, nil); err != nil {
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return errors.New("unmarshal <challenge>: " + err.Error())
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}
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b, err = base64.StdEncoding.DecodeString(string(rspauth))
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if err != nil {
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return err
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}
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fmt.Fprintf(c.conn, "<response xmlns='%s'/>\n", nsSASL)
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break
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}
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clientFinalMessageBare := "c=biws,r=" + serverNonce
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saltedPassword := pbkdf2.Key([]byte(o.Password), salt,
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iterations, shaNewFn().Size(), shaNewFn)
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h := hmac.New(shaNewFn, saltedPassword)
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_, err = h.Write([]byte("Client Key"))
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if err != nil {
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return err
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}
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clientKey := h.Sum(nil)
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h.Reset()
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var storedKey []byte
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switch mechanism {
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case "SCRAM-SHA-512":
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storedKey512 := sha512.Sum512(clientKey)
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storedKey = storedKey512[:]
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case "SCRAM-SHA-256":
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storedKey256 := sha256.Sum256(clientKey)
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storedKey = storedKey256[:]
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case "SCRAM-SHA-1":
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storedKey1 := sha1.Sum(clientKey)
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storedKey = storedKey1[:]
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}
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_, err = h.Write([]byte("Server Key"))
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if err != nil {
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return err
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}
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serverFirstMessage, err := base64.StdEncoding.DecodeString(sfm)
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if err != nil {
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return err
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}
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authMessage := clientFirstMessage + "," + string(serverFirstMessage) +
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"," + clientFinalMessageBare
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h = hmac.New(shaNewFn, storedKey[:])
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_, err = h.Write([]byte(authMessage))
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if err != nil {
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return err
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}
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clientSignature := h.Sum(nil)
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h.Reset()
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if len(clientKey) != len(clientSignature) {
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return errors.New("SCRAM: client key and signature length mismatch")
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}
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clientProof := make([]byte, len(clientKey))
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for i := range clientKey {
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clientProof[i] = clientKey[i] ^ clientSignature[i]
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}
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h = hmac.New(shaNewFn, saltedPassword)
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_, err = h.Write([]byte("Server Key"))
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if err != nil {
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return err
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}
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serverKey := h.Sum(nil)
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h.Reset()
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h = hmac.New(shaNewFn, serverKey)
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_, err = h.Write([]byte(authMessage))
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if err != nil {
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return err
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}
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serverSignature = h.Sum(nil)
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if string(serverSignature) == "" {
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return errors.New("SCRAM: calculated an empty server signature")
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}
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clientFinalMessage := base64.StdEncoding.EncodeToString([]byte(clientFinalMessageBare +
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",p=" + base64.StdEncoding.EncodeToString(clientProof)))
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fmt.Fprintf(StanzaWriter, "<response xmlns='%s'>%s</response>", nsSASL,
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clientFinalMessage)
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}
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if mechanism == "" {
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return fmt.Errorf("PLAIN authentication is not an option: %v", f.Mechanisms.Mechanism)
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if mechanism == "X-OAUTH2" && o.OAuthToken != "" && o.OAuthScope != "" {
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// Oauth authentication: send base64-encoded \x00 user \x00 token.
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raw := "\x00" + user + "\x00" + o.OAuthToken
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enc := make([]byte, base64.StdEncoding.EncodedLen(len(raw)))
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base64.StdEncoding.Encode(enc, []byte(raw))
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fmt.Fprintf(StanzaWriter, "<auth xmlns='%s' mechanism='X-OAUTH2' auth:service='oauth2' "+
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"xmlns:auth='%s'>%s</auth>\n", nsSASL, o.OAuthXmlNs, enc)
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}
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if mechanism == "PLAIN" {
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// Plain authentication: send base64-encoded \x00 user \x00 password.
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raw := "\x00" + user + "\x00" + o.Password
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enc := make([]byte, base64.StdEncoding.EncodedLen(len(raw)))
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base64.StdEncoding.Encode(enc, []byte(raw))
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fmt.Fprintf(c.conn, "<auth xmlns='%s' mechanism='PLAIN'>%s</auth>\n", nsSASL, enc)
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}
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if mechanism == "DIGEST-MD5" {
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// Digest-MD5 authentication
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fmt.Fprintf(StanzaWriter, "<auth xmlns='%s' mechanism='DIGEST-MD5'/>\n", nsSASL)
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var ch saslChallenge
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if err = c.p.DecodeElement(&ch, nil); err != nil {
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return errors.New("unmarshal <challenge>: " + err.Error())
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}
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b, err := base64.StdEncoding.DecodeString(string(ch))
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if err != nil {
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return err
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}
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tokens := map[string]string{}
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for _, token := range strings.Split(string(b), ",") {
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kv := strings.SplitN(strings.TrimSpace(token), "=", 2)
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if len(kv) == 2 {
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if kv[1][0] == '"' && kv[1][len(kv[1])-1] == '"' {
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kv[1] = kv[1][1 : len(kv[1])-1]
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}
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tokens[kv[0]] = kv[1]
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}
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}
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realm, _ := tokens["realm"]
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nonce, _ := tokens["nonce"]
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qop, _ := tokens["qop"]
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charset, _ := tokens["charset"]
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cnonceStr := cnonce()
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digestURI := "xmpp/" + domain
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nonceCount := fmt.Sprintf("%08x", 1)
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digest := saslDigestResponse(user, realm, o.Password, nonce, cnonceStr, "AUTHENTICATE", digestURI, nonceCount)
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message := "username=\"" + user + "\", realm=\"" + realm + "\", nonce=\"" + nonce + "\", cnonce=\"" + cnonceStr +
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"\", nc=" + nonceCount + ", qop=" + qop + ", digest-uri=\"" + digestURI + "\", response=" + digest + ", charset=" + charset
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fmt.Fprintf(StanzaWriter, "<response xmlns='%s'>%s</response>\n", nsSASL, base64.StdEncoding.EncodeToString([]byte(message)))
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var rspauth saslRspAuth
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if err = c.p.DecodeElement(&rspauth, nil); err != nil {
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return errors.New("unmarshal <challenge>: " + err.Error())
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}
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b, err = base64.StdEncoding.DecodeString(string(rspauth))
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if err != nil {
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return err
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}
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fmt.Fprintf(StanzaWriter, "<response xmlns='%s'/>\n", nsSASL)
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}
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}
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if mechanism == "" {
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return fmt.Errorf("PLAIN authentication is not an option: %v", f.Mechanisms.Mechanism)
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}
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// Next message should be either success or failure.
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name, val, err := next(c.p)
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@ -464,6 +609,23 @@ func (c *Client) init(o *Options) error {
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}
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switch v := val.(type) {
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case *saslSuccess:
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if strings.HasPrefix(mechanism, "SCRAM-SHA") {
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successMsg, err := base64.StdEncoding.DecodeString(v.Text)
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if err != nil {
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return err
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}
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if !strings.HasPrefix(string(successMsg), "v=") {
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return errors.New("server sent unexpected content in SCRAM success message")
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}
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serverSignatureReply := strings.SplitN(string(successMsg), "v=", 2)[1]
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serverSignatureRemote, err := base64.StdEncoding.DecodeString(serverSignatureReply)
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if err != nil {
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return err
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}
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if string(serverSignature) != string(serverSignatureRemote) {
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return errors.New("SCRAM: server signature mismatch")
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}
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}
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case *saslFailure:
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errorMessage := v.Text
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if errorMessage == "" {
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