Merge pull request #100 from wneessen/feature/97_fork-the-netsmtp-pac…

…kage-from-stdlib-into-go-mail

Fork the net/smtp package from Go's stdlib into go-mail

LICENSES/BSD-3-Clause.txt

@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

LICENSES/MIT.txt

@@ -1,9 +1,18 @@
 MIT License
 
-Copyright (c) <year> <copyright holders>
+Copyright (c) 2022-2023 The go-mail Authors
 
-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:
+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 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.
+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.go

@@ -10,12 +10,11 @@ import (
 	"errors"
 	"fmt"
 	"net"
-	"net/smtp"
 	"os"
 	"strings"
 	"time"
 
-	"github.com/wneessen/go-mail/auth"
+	"github.com/wneessen/go-mail/smtp"
 )
 
 // Defaults
@@ -593,7 +592,7 @@ func (c *Client) auth() error {
 			if !strings.Contains(sat, string(SMTPAuthLogin)) {
 				return ErrLoginAuthNotSupported
 			}
-			c.sa = auth.LoginAuth(c.user, c.pass, c.host)
+			c.sa = smtp.LoginAuth(c.user, c.pass, c.host)
 		case SMTPAuthCramMD5:
 			if !strings.Contains(sat, string(SMTPAuthCramMD5)) {
 				return ErrCramMD5AuthNotSupported

client_test.go

@@ -9,14 +9,13 @@ import (
 	"crypto/tls"
 	"errors"
 	"fmt"
-	"net/smtp"
 	"os"
 	"strconv"
 	"strings"
 	"testing"
 	"time"
 
-	"github.com/wneessen/go-mail/auth"
+	"github.com/wneessen/go-mail/smtp"
 )
 
 // DefaultHost is used as default hostname for the Client
@@ -496,7 +495,7 @@ func TestSetSMTPAuthCustom(t *testing.T) {
 	}{
 		{"SMTPAuth: PLAIN", smtp.PlainAuth("", "", "", ""), "PLAIN", false},
 		{"SMTPAuth: CRAM-MD5", smtp.CRAMMD5Auth("", ""), "CRAM-MD5", false},
-		{"SMTPAuth: LOGIN", auth.LoginAuth("", "", ""), "LOGIN", false},
+		{"SMTPAuth: LOGIN", smtp.LoginAuth("", "", ""), "LOGIN", false},
 	}
 	si := smtp.ServerInfo{TLS: true}
 	for _, tt := range tests {
@@ -584,7 +583,7 @@ func TestClient_DialWithContextInvalidAuth(t *testing.T) {
 	}
 	c.user = "invalid"
 	c.pass = "invalid"
-	c.SetSMTPAuthCustom(auth.LoginAuth("invalid", "invalid", "invalid"))
+	c.SetSMTPAuthCustom(smtp.LoginAuth("invalid", "invalid", "invalid"))
 	ctx := context.Background()
 	if err := c.DialWithContext(ctx); err == nil {
 		t.Errorf("dial succeeded but was supposed to fail")

smtp/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

smtp/auth.go

@@ -0,0 +1,44 @@
+// 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
+
+// Auth is implemented by an SMTP authentication mechanism.
+type Auth interface {
+	// Start begins an authentication with a server.
+	// It returns the name of the authentication protocol
+	// and optionally data to include in the initial AUTH message
+	// sent to the server.
+	// If it returns a non-nil error, the SMTP client aborts
+	// the authentication attempt and closes the connection.
+	Start(server *ServerInfo) (proto string, toServer []byte, err error)
+
+	// Next continues the authentication. The server has just sent
+	// the fromServer data. If more is true, the server expects a
+	// response, which Next should return as toServer; otherwise
+	// Next should return toServer == nil.
+	// If Next returns a non-nil error, the SMTP client aborts
+	// the authentication attempt and closes the connection.
+	Next(fromServer []byte, more bool) (toServer []byte, err error)
+}
+
+// ServerInfo records information about an SMTP server.
+type ServerInfo struct {
+	Name string   // SMTP server name
+	TLS  bool     // using TLS, with valid certificate for Name
+	Auth []string // advertised authentication mechanisms
+}
+
+func isLocalhost(name string) bool {
+	return name == "localhost" || name == "127.0.0.1" || name == "::1"
+}

smtp/auth_cram_md5.go

@@ -0,0 +1,50 @@
+// 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
+
+//go:build go1.19
+// +build go1.19
+
+package smtp
+
+import (
+	"crypto/hmac"
+	"crypto/md5"
+	"fmt"
+)
+
+// cramMD5Auth is the type that satisfies the Auth interface for the "SMTP CRAM_MD5" auth
+type cramMD5Auth struct {
+	username, secret string
+}
+
+// CRAMMD5Auth returns an Auth that implements the CRAM-MD5 authentication
+// mechanism as defined in RFC 2195.
+// The returned Auth uses the given username and secret to authenticate
+// to the server using the challenge-response mechanism.
+func CRAMMD5Auth(username, secret string) Auth {
+	return &cramMD5Auth{username, secret}
+}
+
+func (a *cramMD5Auth) Start(_ *ServerInfo) (string, []byte, error) {
+	return "CRAM-MD5", nil, nil
+}
+
+func (a *cramMD5Auth) Next(fromServer []byte, more bool) ([]byte, error) {
+	if more {
+		d := hmac.New(md5.New, []byte(a.secret))
+		d.Write(fromServer)
+		s := make([]byte, 0, d.Size())
+		return fmt.Appendf(nil, "%s %x", a.username, d.Sum(s)), nil
+	}
+	return nil, nil
+}

smtp/auth_cram_md5_118.go

@@ -0,0 +1,52 @@
+// 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
+
+//go:build !go1.19
+// +build !go1.19
+
+package smtp
+
+import (
+	"crypto/hmac"
+	"crypto/md5"
+	"fmt"
+)
+
+// cramMD5Auth is the type that satisfies the Auth interface for the "SMTP CRAM_MD5" auth
+type cramMD5Auth struct {
+	username, secret string
+}
+
+// CRAMMD5Auth returns an Auth that implements the CRAM-MD5 authentication
+// mechanism as defined in RFC 2195.
+// The returned Auth uses the given username and secret to authenticate
+// to the server using the challenge-response mechanism.
+func CRAMMD5Auth(username, secret string) Auth {
+	return &cramMD5Auth{username, secret}
+}
+
+func (a *cramMD5Auth) Start(_ *ServerInfo) (string, []byte, error) {
+	return "CRAM-MD5", nil, nil
+}
+
+// Backport of: https://github.com/golang/go/commit/58158e990f272774e615c9abd8662bf0198c29aa#diff-772fc9f5d0c86f26e35158fb3e7a71a4967d18b4ec23a5dbb60781ab0babf426
+// to guarantee backwards compatiblity with Go 1.16-1.18
+func (a *cramMD5Auth) Next(fromServer []byte, more bool) ([]byte, error) {
+	if more {
+		d := hmac.New(md5.New, []byte(a.secret))
+		d.Write(fromServer)
+		s := make([]byte, 0, d.Size())
+		return []byte(fmt.Sprintf("%s %x", a.username, d.Sum(s))), nil
+	}
+	return nil, nil
+}