133 lines
3.5 KiB
Go
133 lines
3.5 KiB
Go
package client
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import (
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"crypto/md5"
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"crypto/rand"
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"encoding/base64"
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"errors"
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"fmt"
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"math/big"
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"strings"
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"dev.sum7.eu/genofire/yaja/messages"
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)
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func (client *Client) auth(password string) error {
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f, err := client.startStream()
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if err != nil {
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return err
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}
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//auth:
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mechanism := ""
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challenge := &messages.SASLChallenge{}
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response := &messages.SASLResponse{}
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for _, m := range f.Mechanisms.Mechanism {
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client.Logging.Debugf("try auth with '%s'", m)
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if m == "SCRAM-SHA-1" {
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/*
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mechanism = m
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TODO
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break
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*/
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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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client.Send(&messages.SASLAuth{
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Mechanism: m,
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})
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if err := client.ReadDecode(challenge); err != nil {
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return err
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}
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b, err := base64.StdEncoding.DecodeString(challenge.Body)
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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/" + client.JID.Domain
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nonceCount := fmt.Sprintf("%08x", 1)
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digest := saslDigestResponse(client.JID.Local, realm, password, nonce, cnonceStr, "AUTHENTICATE", digestURI, nonceCount)
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message := "username=\"" + client.JID.Local + "\", 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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response.Body = base64.StdEncoding.EncodeToString([]byte(message))
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client.Send(response)
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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" + client.JID.Local + "\x00" + 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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client.Send(&messages.SASLAuth{
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Mechanism: "PLAIN",
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Body: string(enc),
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})
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break
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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: %s", f.Mechanisms.Mechanism)
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}
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client.Logging.Info("used auth with '%s'", mechanism)
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element, err := client.Read()
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if err != nil {
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return err
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}
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fail := messages.SASLFailure{}
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if err := client.Decode(&fail, element); err == nil {
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return errors.New(messages.XMLChildrenString(fail) + " : " + fail.Body)
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}
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if err := client.Decode(&messages.SASLSuccess{}, element); err != nil {
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return errors.New("auth failed - with unexpected answer")
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}
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return nil
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}
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func saslDigestResponse(username, realm, passwd, nonce, cnonceStr, authenticate, digestURI, nonceCountStr string) string {
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h := func(text string) []byte {
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h := md5.New()
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h.Write([]byte(text))
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return h.Sum(nil)
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}
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hex := func(bytes []byte) string {
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return fmt.Sprintf("%x", bytes)
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}
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kd := func(secret, data string) []byte {
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return h(secret + ":" + data)
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}
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a1 := string(h(username+":"+realm+":"+passwd)) + ":" + nonce + ":" + cnonceStr
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a2 := authenticate + ":" + digestURI
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response := hex(kd(hex(h(a1)), nonce+":"+nonceCountStr+":"+cnonceStr+":auth:"+hex(h(a2))))
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return response
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}
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func cnonce() string {
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randSize := big.NewInt(0)
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randSize.Lsh(big.NewInt(1), 64)
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cn, err := rand.Int(rand.Reader, randSize)
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if err != nil {
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return ""
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}
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return fmt.Sprintf("%016x", cn)
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}
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