mirror of
https://github.com/wneessen/go-mail.git
synced 2024-11-14 01:42:54 +01:00
60 lines
2.1 KiB
Go
60 lines
2.1 KiB
Go
// SPDX-FileCopyrightText: Copyright 2010 The Go Authors. All rights reserved.
|
|
// SPDX-FileCopyrightText: Copyright (c) 2022-2023 The go-mail Authors
|
|
//
|
|
// Original net/smtp code from the Go stdlib by the Go Authors.
|
|
// Use of this source code is governed by a BSD-style
|
|
// LICENSE file that can be found in this directory.
|
|
//
|
|
// go-mail specific modifications by the go-mail Authors.
|
|
// Licensed under the MIT License.
|
|
// See [PROJECT ROOT]/LICENSES directory for more information.
|
|
//
|
|
// SPDX-License-Identifier: BSD-3-Clause AND MIT
|
|
|
|
package smtp
|
|
|
|
import (
|
|
"errors"
|
|
)
|
|
|
|
// plainAuth is the type that satisfies the Auth interface for the "SMTP PLAIN" auth
|
|
type plainAuth struct {
|
|
identity, username, password string
|
|
host string
|
|
}
|
|
|
|
// PlainAuth returns an Auth that implements the PLAIN authentication
|
|
// mechanism as defined in RFC 4616. The returned Auth uses the given
|
|
// username and password to authenticate to host and act as identity.
|
|
// Usually identity should be the empty string, to act as username.
|
|
//
|
|
// PlainAuth will only send the credentials if the connection is using TLS
|
|
// or is connected to localhost. Otherwise authentication will fail with an
|
|
// error, without sending the credentials.
|
|
func PlainAuth(identity, username, password, host string) Auth {
|
|
return &plainAuth{identity, username, password, host}
|
|
}
|
|
|
|
func (a *plainAuth) Start(server *ServerInfo) (string, []byte, error) {
|
|
// Must have TLS, or else localhost server.
|
|
// Note: If TLS is not true, then we can't trust ANYTHING in ServerInfo.
|
|
// In particular, it doesn't matter if the server advertises PLAIN auth.
|
|
// That might just be the attacker saying
|
|
// "it's ok, you can trust me with your password."
|
|
if !server.TLS && !isLocalhost(server.Name) {
|
|
return "", nil, errors.New("unencrypted connection")
|
|
}
|
|
if server.Name != a.host {
|
|
return "", nil, errors.New("wrong host name")
|
|
}
|
|
resp := []byte(a.identity + "\x00" + a.username + "\x00" + a.password)
|
|
return "PLAIN", resp, nil
|
|
}
|
|
|
|
func (a *plainAuth) Next(_ []byte, more bool) ([]byte, error) {
|
|
if more {
|
|
// We've already sent everything.
|
|
return nil, errors.New("unexpected server challenge")
|
|
}
|
|
return nil, nil
|
|
}
|