95 lines
2.5 KiB
Go
95 lines
2.5 KiB
Go
package xmpp
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import (
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"encoding/base64"
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"encoding/xml"
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"errors"
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"fmt"
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"io"
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"gosrc.io/xmpp/stanza"
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)
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// Credential is used to pass the type of secret that will be used to connect to XMPP server.
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// It can be either a password or an OAuth 2 bearer token.
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type Credential struct {
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secret string
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mechanisms []string
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}
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func Password(pwd string) Credential {
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credential := Credential{
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secret: pwd,
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mechanisms: []string{"PLAIN"},
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}
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return credential
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}
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func OAuthToken(token string) Credential {
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credential := Credential{
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secret: token,
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mechanisms: []string{"X-OAUTH2"},
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}
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return credential
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}
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// ============================================================================
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// Authentication flow for SASL mechanisms
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func authSASL(socket io.ReadWriter, decoder *xml.Decoder, f stanza.StreamFeatures, user string, credential Credential) (err error) {
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var matchingMech string
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for _, mech := range credential.mechanisms {
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if isSupportedMech(mech, f.Mechanisms.Mechanism) {
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matchingMech = mech
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break
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}
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}
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switch matchingMech {
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case "PLAIN", "X-OAUTH2":
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// TODO: Implement other type of SASL mechanisms
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return authPlain(socket, decoder, matchingMech, user, credential.secret)
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default:
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err := fmt.Errorf("no matching authentication (%v) supported by server: %v", credential.mechanisms, f.Mechanisms.Mechanism)
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return NewConnError(err, true)
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}
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}
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// Plain authentication: send base64-encoded \x00 user \x00 password
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func authPlain(socket io.ReadWriter, decoder *xml.Decoder, mech string, user string, secret string) error {
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raw := "\x00" + user + "\x00" + secret
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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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_, err := fmt.Fprintf(socket, "<auth xmlns='%s' mechanism='%s'>%s</auth>", stanza.NSSASL, mech, enc)
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if err != nil {
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return err
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}
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// Next message should be either success or failure.
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val, err := stanza.NextPacket(decoder)
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if err != nil {
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return err
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}
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switch v := val.(type) {
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case stanza.SASLSuccess:
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case stanza.SASLFailure:
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// v.Any is type of sub-element in failure, which gives a description of what failed.
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err := errors.New("auth failure: " + v.Any.Local)
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return NewConnError(err, true)
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default:
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return errors.New("expected SASL success or failure, got " + v.Name())
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}
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return err
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}
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// isSupportedMech returns true if the mechanism is supported in the provided list.
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func isSupportedMech(mech string, mechanisms []string) bool {
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for _, m := range mechanisms {
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if mech == m {
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return true
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}
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}
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return false
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}
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