Initial commit
This commit is contained in:
commit
d1d71c8614
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.idea
|
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|
|||
# GNU LESSER GENERAL PUBLIC LICENSE
|
||||
|
||||
Version 3, 29 June 2007
|
||||
|
||||
Copyright (C) 2007 Free Software Foundation, Inc.
|
||||
<https://fsf.org/>
|
||||
|
||||
Everyone is permitted to copy and distribute verbatim copies of this
|
||||
license document, but changing it is not allowed.
|
||||
|
||||
This version of the GNU Lesser General Public License incorporates the
|
||||
terms and conditions of version 3 of the GNU General Public License,
|
||||
supplemented by the additional permissions listed below.
|
||||
|
||||
## 0. Additional Definitions.
|
||||
|
||||
As used herein, "this License" refers to version 3 of the GNU Lesser
|
||||
General Public License, and the "GNU GPL" refers to version 3 of the
|
||||
GNU General Public License.
|
||||
|
||||
"The Library" refers to a covered work governed by this License, other
|
||||
than an Application or a Combined Work as defined below.
|
||||
|
||||
An "Application" is any work that makes use of an interface provided
|
||||
by the Library, but which is not otherwise based on the Library.
|
||||
Defining a subclass of a class defined by the Library is deemed a mode
|
||||
of using an interface provided by the Library.
|
||||
|
||||
A "Combined Work" is a work produced by combining or linking an
|
||||
Application with the Library. The particular version of the Library
|
||||
with which the Combined Work was made is also called the "Linked
|
||||
Version".
|
||||
|
||||
The "Minimal Corresponding Source" for a Combined Work means the
|
||||
Corresponding Source for the Combined Work, excluding any source code
|
||||
for portions of the Combined Work that, considered in isolation, are
|
||||
based on the Application, and not on the Linked Version.
|
||||
|
||||
The "Corresponding Application Code" for a Combined Work means the
|
||||
object code and/or source code for the Application, including any data
|
||||
and utility programs needed for reproducing the Combined Work from the
|
||||
Application, but excluding the System Libraries of the Combined Work.
|
||||
|
||||
## 1. Exception to Section 3 of the GNU GPL.
|
||||
|
||||
You may convey a covered work under sections 3 and 4 of this License
|
||||
without being bound by section 3 of the GNU GPL.
|
||||
|
||||
## 2. Conveying Modified Versions.
|
||||
|
||||
If you modify a copy of the Library, and, in your modifications, a
|
||||
facility refers to a function or data to be supplied by an Application
|
||||
that uses the facility (other than as an argument passed when the
|
||||
facility is invoked), then you may convey a copy of the modified
|
||||
version:
|
||||
|
||||
- a) under this License, provided that you make a good faith effort
|
||||
to ensure that, in the event an Application does not supply the
|
||||
function or data, the facility still operates, and performs
|
||||
whatever part of its purpose remains meaningful, or
|
||||
- b) under the GNU GPL, with none of the additional permissions of
|
||||
this License applicable to that copy.
|
||||
|
||||
## 3. Object Code Incorporating Material from Library Header Files.
|
||||
|
||||
The object code form of an Application may incorporate material from a
|
||||
header file that is part of the Library. You may convey such object
|
||||
code under terms of your choice, provided that, if the incorporated
|
||||
material is not limited to numerical parameters, data structure
|
||||
layouts and accessors, or small macros, inline functions and templates
|
||||
(ten or fewer lines in length), you do both of the following:
|
||||
|
||||
- a) Give prominent notice with each copy of the object code that
|
||||
the Library is used in it and that the Library and its use are
|
||||
covered by this License.
|
||||
- b) Accompany the object code with a copy of the GNU GPL and this
|
||||
license document.
|
||||
|
||||
## 4. Combined Works.
|
||||
|
||||
You may convey a Combined Work under terms of your choice that, taken
|
||||
together, effectively do not restrict modification of the portions of
|
||||
the Library contained in the Combined Work and reverse engineering for
|
||||
debugging such modifications, if you also do each of the following:
|
||||
|
||||
- a) Give prominent notice with each copy of the Combined Work that
|
||||
the Library is used in it and that the Library and its use are
|
||||
covered by this License.
|
||||
- b) Accompany the Combined Work with a copy of the GNU GPL and this
|
||||
license document.
|
||||
- c) For a Combined Work that displays copyright notices during
|
||||
execution, include the copyright notice for the Library among
|
||||
these notices, as well as a reference directing the user to the
|
||||
copies of the GNU GPL and this license document.
|
||||
- d) Do one of the following:
|
||||
- 0) Convey the Minimal Corresponding Source under the terms of
|
||||
this License, and the Corresponding Application Code in a form
|
||||
suitable for, and under terms that permit, the user to
|
||||
recombine or relink the Application with a modified version of
|
||||
the Linked Version to produce a modified Combined Work, in the
|
||||
manner specified by section 6 of the GNU GPL for conveying
|
||||
Corresponding Source.
|
||||
- 1) Use a suitable shared library mechanism for linking with
|
||||
the Library. A suitable mechanism is one that (a) uses at run
|
||||
time a copy of the Library already present on the user's
|
||||
computer system, and (b) will operate properly with a modified
|
||||
version of the Library that is interface-compatible with the
|
||||
Linked Version.
|
||||
- e) Provide Installation Information, but only if you would
|
||||
otherwise be required to provide such information under section 6
|
||||
of the GNU GPL, and only to the extent that such information is
|
||||
necessary to install and execute a modified version of the
|
||||
Combined Work produced by recombining or relinking the Application
|
||||
with a modified version of the Linked Version. (If you use option
|
||||
4d0, the Installation Information must accompany the Minimal
|
||||
Corresponding Source and Corresponding Application Code. If you
|
||||
use option 4d1, you must provide the Installation Information in
|
||||
the manner specified by section 6 of the GNU GPL for conveying
|
||||
Corresponding Source.)
|
||||
|
||||
## 5. Combined Libraries.
|
||||
|
||||
You may place library facilities that are a work based on the Library
|
||||
side by side in a single library together with other library
|
||||
facilities that are not Applications and are not covered by this
|
||||
License, and convey such a combined library under terms of your
|
||||
choice, if you do both of the following:
|
||||
|
||||
- a) Accompany the combined library with a copy of the same work
|
||||
based on the Library, uncombined with any other library
|
||||
facilities, conveyed under the terms of this License.
|
||||
- b) Give prominent notice with the combined library that part of it
|
||||
is a work based on the Library, and explaining where to find the
|
||||
accompanying uncombined form of the same work.
|
||||
|
||||
## 6. Revised Versions of the GNU Lesser General Public License.
|
||||
|
||||
The Free Software Foundation may publish revised and/or new versions
|
||||
of the GNU Lesser General Public License from time to time. Such new
|
||||
versions will be similar in spirit to the present version, but may
|
||||
differ in detail to address new problems or concerns.
|
||||
|
||||
Each version is given a distinguishing version number. If the Library
|
||||
as you received it specifies that a certain numbered version of the
|
||||
GNU Lesser General Public License "or any later version" applies to
|
||||
it, you have the option of following the terms and conditions either
|
||||
of that published version or of any later version published by the
|
||||
Free Software Foundation. If the Library as you received it does not
|
||||
specify a version number of the GNU Lesser General Public License, you
|
||||
may choose any version of the GNU Lesser General Public License ever
|
||||
published by the Free Software Foundation.
|
||||
|
||||
If the Library as you received it specifies that a proxy can decide
|
||||
whether future versions of the GNU Lesser General Public License shall
|
||||
apply, that proxy's public statement of acceptance of any version is
|
||||
permanent authorization for you to choose that version for the
|
||||
Library.
|
||||
|
|
@ -0,0 +1,5 @@
|
|||
# SMTP
|
||||
|
||||
A comprehensive library for sending and receiving emails using the SMTP protocol, written in Go.
|
||||
|
||||
[](https://goreportcard.com/report/git.ailur.dev/ailur/smtp) [](https://pkg.go.dev/git.ailur.dev/ailur/smtp)
|
||||
|
|
@ -0,0 +1,8 @@
|
|||
module smtp
|
||||
|
||||
go 1.23
|
||||
|
||||
require (
|
||||
git.ailur.dev/ailur/spf v1.0.1
|
||||
github.com/google/uuid v1.6.0
|
||||
)
|
||||
|
|
@ -0,0 +1,4 @@
|
|||
git.ailur.dev/ailur/spf v1.0.1 h1:ApkuF2YsQJgUMo0I4cmQcHBERXZ+ZspOkqMe2lyaUfk=
|
||||
git.ailur.dev/ailur/spf v1.0.1/go.mod h1:j+l6sReELJT3VCyAt/DgOfNqNYU/AvzJvj5vgLt3WGo=
|
||||
github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
|
||||
github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
|
||||
|
|
@ -0,0 +1,792 @@
|
|||
package smtp
|
||||
|
||||
import (
|
||||
"errors"
|
||||
"fmt"
|
||||
"io"
|
||||
"net"
|
||||
"strconv"
|
||||
"strings"
|
||||
|
||||
"crypto/tls"
|
||||
"net/textproto"
|
||||
|
||||
"git.ailur.dev/ailur/spf"
|
||||
"github.com/google/uuid"
|
||||
)
|
||||
|
||||
var (
|
||||
defaultCapabilities = []string{
|
||||
"250-8BITMIME",
|
||||
"250-ENHANCEDSTATUSCODES",
|
||||
"250-SMTPUTF8",
|
||||
"250 BINARYMIME",
|
||||
}
|
||||
queue = make(map[uuid.UUID]*MailQueueItem)
|
||||
)
|
||||
|
||||
// MailQueueItem is a struct that represents an item in the mail queue
|
||||
type MailQueueItem struct {
|
||||
From *Address
|
||||
To []*Address
|
||||
Host string
|
||||
}
|
||||
|
||||
// ViewMailQueue returns the current mail queue
|
||||
func ViewMailQueue() map[uuid.UUID]*MailQueueItem {
|
||||
return queue
|
||||
}
|
||||
|
||||
// Address is a struct that represents an email address
|
||||
type Address struct {
|
||||
Name string
|
||||
Address string
|
||||
}
|
||||
|
||||
// Mail is a struct that represents an email
|
||||
type Mail struct {
|
||||
From *Address
|
||||
To []*Address
|
||||
Data []byte
|
||||
}
|
||||
|
||||
// DatabaseBackend is a struct that represents a database backend
|
||||
type DatabaseBackend struct {
|
||||
CheckUser func(*Address) (bool, error)
|
||||
WriteMail func(*Mail) (uuid.UUID, error)
|
||||
}
|
||||
|
||||
// AuthenticationBackend is a struct that represents an authentication backend
|
||||
type AuthenticationBackend struct {
|
||||
Authenticate func(string) (*Address, error)
|
||||
}
|
||||
|
||||
func readMultilineCodeResponse(conn *textproto.Conn) (int, string, error) {
|
||||
var lines strings.Builder
|
||||
for {
|
||||
line, err := conn.ReadLine()
|
||||
if err != nil {
|
||||
return 0, "", err
|
||||
}
|
||||
|
||||
lines.WriteString(line)
|
||||
|
||||
code, err := strconv.Atoi(line[:3])
|
||||
if err != nil {
|
||||
return 0, "", err
|
||||
}
|
||||
|
||||
if line[3] != '-' {
|
||||
return code, lines.String(), nil
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func systemError(err error, receiver *Address, database DatabaseBackend) {
|
||||
_, _ = database.WriteMail(&Mail{
|
||||
From: &Address{
|
||||
Name: "EMail System",
|
||||
Address: "system",
|
||||
},
|
||||
To: []*Address{receiver},
|
||||
Data: []byte(fmt.Sprintf("Hello there. This is the EMail system.\n We're sorry, but an error occurred while trying to send your email. The error was: %s. The email has not been sent.", err.Error())),
|
||||
})
|
||||
}
|
||||
|
||||
func sendEmail(args SenderArgs, mail *Mail, database DatabaseBackend, queueID uuid.UUID) {
|
||||
mxs, err := net.LookupMX(mail.To[0].Address)
|
||||
if err != nil {
|
||||
systemError(err, queue[queueID].From, database)
|
||||
delete(queue, queueID)
|
||||
return
|
||||
}
|
||||
|
||||
ips, err := net.LookupIP(mxs[0].Host)
|
||||
if err != nil {
|
||||
systemError(err, queue[queueID].From, database)
|
||||
delete(queue, queueID)
|
||||
return
|
||||
}
|
||||
|
||||
conn, err := net.Dial("tcp", ips[0].String()+":25")
|
||||
if err != nil {
|
||||
systemError(err, queue[queueID].From, database)
|
||||
delete(queue, queueID)
|
||||
return
|
||||
}
|
||||
|
||||
err = Send(args, mail, conn, mxs[0].Host)
|
||||
if err != nil {
|
||||
systemError(err, queue[queueID].From, database)
|
||||
delete(queue, queueID)
|
||||
return
|
||||
}
|
||||
|
||||
err = conn.Close()
|
||||
if err != nil {
|
||||
systemError(err, queue[queueID].From, database)
|
||||
delete(queue, queueID)
|
||||
return
|
||||
}
|
||||
|
||||
delete(queue, queueID)
|
||||
}
|
||||
|
||||
func speakMultiLine(conn *textproto.Conn, lines []string) error {
|
||||
for _, line := range lines {
|
||||
err := conn.PrintfLine(line)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// Receiver is a struct that represents an SMTP receiver
|
||||
type Receiver struct {
|
||||
underlyingListener net.Listener
|
||||
hostname string
|
||||
ownedDomains map[string]any
|
||||
enforceTLS bool
|
||||
tlsConfig *tls.Config
|
||||
database DatabaseBackend
|
||||
auth AuthenticationBackend
|
||||
}
|
||||
|
||||
// NewReceiver creates a new Receiver
|
||||
func NewReceiver(conn net.Listener, hostname string, ownedDomains []string, enforceTLS bool, database DatabaseBackend, authentication AuthenticationBackend, tlsConfig *tls.Config) *Receiver {
|
||||
var ownedDomainsMap = make(map[string]any)
|
||||
for _, domain := range ownedDomains {
|
||||
ownedDomainsMap[domain] = nil
|
||||
}
|
||||
return &Receiver{
|
||||
underlyingListener: conn,
|
||||
hostname: hostname,
|
||||
ownedDomains: ownedDomainsMap,
|
||||
enforceTLS: enforceTLS,
|
||||
tlsConfig: tlsConfig,
|
||||
database: database,
|
||||
auth: authentication,
|
||||
}
|
||||
}
|
||||
|
||||
// Close closes the connection to the Receiver
|
||||
func (fr *Receiver) Close() error {
|
||||
return fr.underlyingListener.Close()
|
||||
}
|
||||
|
||||
// Serve serves the Receiver. It will always return a non-nil error
|
||||
func (fr *Receiver) Serve() error {
|
||||
for {
|
||||
conn, err := fr.underlyingListener.Accept()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
go fr.handleConnection(conn)
|
||||
}
|
||||
}
|
||||
|
||||
func (fr *Receiver) handleConnection(conn net.Conn) {
|
||||
var state struct {
|
||||
HELO bool
|
||||
AUTH *Address
|
||||
TLS bool
|
||||
FROM *Address
|
||||
RCPT []*Address
|
||||
DATA []byte
|
||||
}
|
||||
|
||||
submissionSlice := strings.Split(conn.LocalAddr().String(), ":")
|
||||
isSubmission := submissionSlice[len(submissionSlice)-1] != "25"
|
||||
textProto := textproto.NewConn(conn)
|
||||
|
||||
err := textProto.PrintfLine("220 %s ESMTP At your service", fr.hostname)
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
|
||||
fmt.Println("Connection from", conn.RemoteAddr().String())
|
||||
|
||||
for {
|
||||
line, err := textProto.ReadLine()
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
|
||||
switch {
|
||||
case strings.HasPrefix(line, "QUIT"):
|
||||
err = textProto.PrintfLine("221 2.0.0 See you soon")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
}
|
||||
_ = conn.Close()
|
||||
return
|
||||
case strings.HasPrefix(line, "RSET"):
|
||||
state.HELO = false
|
||||
state.AUTH = nil
|
||||
state.FROM = nil
|
||||
state.RCPT = nil
|
||||
state.DATA = nil
|
||||
err = textProto.PrintfLine("250 2.0.0 Connection reset")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
case strings.HasPrefix(line, "NOOP"):
|
||||
err = textProto.PrintfLine("250 2.0.0 Take your time")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
case strings.HasPrefix(line, "HELO"):
|
||||
if state.HELO {
|
||||
err = textProto.PrintfLine("503 5.5.1 HELO already called")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
} else {
|
||||
state.HELO = true
|
||||
err = textProto.PrintfLine("250 %s, ready to receive mail", fr.hostname)
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
}
|
||||
case strings.HasPrefix(line, "EHLO"):
|
||||
if state.HELO {
|
||||
err = textProto.PrintfLine("503 5.5.1 EHLO already called")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
} else {
|
||||
var capabilities []string
|
||||
if fr.tlsConfig != nil {
|
||||
capabilities = append(capabilities, "250-STARTTLS")
|
||||
}
|
||||
if fr.enforceTLS {
|
||||
capabilities = append(capabilities, "250-REQUIRETLS")
|
||||
}
|
||||
capabilities = append(capabilities, defaultCapabilities...)
|
||||
state.HELO = true
|
||||
err = speakMultiLine(textProto, capabilities)
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
}
|
||||
case strings.HasPrefix(line, "AUTH"):
|
||||
if !isSubmission {
|
||||
err = textProto.PrintfLine("503 5.5.1 AUTH only allowed on submission port")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
|
||||
if !state.TLS && fr.enforceTLS {
|
||||
err = textProto.PrintfLine("530 5.7.0 Must issue a STARTTLS command first")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
|
||||
if state.AUTH != nil {
|
||||
err = textProto.PrintfLine("503 5.5.1 AUTH already called")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
} else {
|
||||
address, err := fr.auth.Authenticate(line)
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
|
||||
if address == nil {
|
||||
err = textProto.PrintfLine("535 5.7.8 Authentication failed")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
} else {
|
||||
state.AUTH = address
|
||||
err = textProto.PrintfLine("235 2.7.0 Authentication successful")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
case strings.HasPrefix(line, "STARTTLS"):
|
||||
if state.TLS {
|
||||
err = textProto.PrintfLine("503 5.5.1 STARTTLS already called")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
} else {
|
||||
err = textProto.PrintfLine("220 2.0.0 Ready to start TLS")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
|
||||
tlsConn := tls.Server(conn, fr.tlsConfig)
|
||||
textProto = textproto.NewConn(tlsConn)
|
||||
|
||||
state.HELO = false
|
||||
state.AUTH = nil
|
||||
state.FROM = nil
|
||||
state.RCPT = nil
|
||||
state.DATA = nil
|
||||
state.TLS = true
|
||||
}
|
||||
case strings.HasPrefix(line, "MAIL FROM"):
|
||||
if !state.HELO {
|
||||
err = textProto.PrintfLine("503 5.5.1 HELO required")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
|
||||
if !state.TLS && fr.enforceTLS {
|
||||
err = textProto.PrintfLine("530 5.7.0 Must issue a STARTTLS command first")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
|
||||
addressSlice := strings.Split(strings.TrimPrefix(strings.TrimSuffix(line, ">"), "MAIL FROM:<"), "@")
|
||||
|
||||
address := &Address{
|
||||
Name: addressSlice[0],
|
||||
Address: addressSlice[1],
|
||||
}
|
||||
|
||||
if isSubmission {
|
||||
if state.AUTH == nil {
|
||||
err = textProto.PrintfLine("503 5.5.1 AUTH required")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
|
||||
if *address != *state.AUTH {
|
||||
err = textProto.PrintfLine("535 5.7.8 Authenticated wrong user")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
} else {
|
||||
err := spf.CheckIP(strings.Split(conn.RemoteAddr().String(), ":")[0], address.Address)
|
||||
if err != nil {
|
||||
if err.Type() == spf.ErrTypeInternal {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
} else {
|
||||
err := textProto.PrintfLine("550 5.7.1 SPF check failed")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
state.FROM = address
|
||||
err = textProto.PrintfLine("250 2.1.0 Sender OK")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
case strings.HasPrefix(line, "RCPT TO"):
|
||||
if !state.TLS && fr.enforceTLS {
|
||||
err = textProto.PrintfLine("530 5.7.0 Must issue a STARTTLS command first")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
|
||||
addressSlice := strings.Split(strings.TrimPrefix(strings.TrimSuffix(line, ">"), "RCPT TO:<"), "@")
|
||||
address := &Address{
|
||||
Name: addressSlice[0],
|
||||
Address: addressSlice[1],
|
||||
}
|
||||
|
||||
if isSubmission {
|
||||
if state.AUTH == nil {
|
||||
err = textProto.PrintfLine("503 5.5.1 AUTH required")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
} else {
|
||||
_, ok := fr.ownedDomains[address.Address]
|
||||
if !ok {
|
||||
err = textProto.PrintfLine("503 5.5.1 Relaying not allowed")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
|
||||
ok, err := fr.database.CheckUser(address)
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
|
||||
if !ok {
|
||||
err = textProto.PrintfLine("550 5.1.1 User not found")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
|
||||
}
|
||||
}
|
||||
|
||||
state.RCPT = append(state.RCPT, address)
|
||||
err = textProto.PrintfLine("250 2.1.5 Recipient OK")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
case strings.HasPrefix(line, "DATA"):
|
||||
if !state.TLS && fr.enforceTLS {
|
||||
err = textProto.PrintfLine("530 5.7.0 Must issue a STARTTLS command first")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
|
||||
if state.FROM == nil {
|
||||
err = textProto.PrintfLine("503 5.5.1 MAIL FROM required")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
|
||||
if len(state.RCPT) == 0 {
|
||||
err = textProto.PrintfLine("503 5.5.1 RCPT TO required")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
continue
|
||||
}
|
||||
|
||||
err = textProto.PrintfLine("354 2.0.0 Start mail input; end with <CRLF>.<CRLF>")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
|
||||
state.DATA, err = io.ReadAll(textProto.DotReader())
|
||||
|
||||
mail := &Mail{
|
||||
From: state.FROM,
|
||||
To: state.RCPT,
|
||||
Data: state.DATA,
|
||||
}
|
||||
|
||||
if !isSubmission {
|
||||
_, err := fr.database.WriteMail(mail)
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine(err.Error())
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
|
||||
err = textProto.PrintfLine("250 2.0.0 Message accepted for delivery")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
} else {
|
||||
queueID := uuid.New()
|
||||
|
||||
queue[queueID] = &MailQueueItem{
|
||||
From: state.FROM,
|
||||
To: state.RCPT,
|
||||
Host: strings.Split(conn.RemoteAddr().String(), ":")[0],
|
||||
}
|
||||
go sendEmail(SenderArgs{
|
||||
Hostname: fr.hostname,
|
||||
EnforceTLS: fr.enforceTLS,
|
||||
}, mail, fr.database, queueID)
|
||||
|
||||
err = textProto.PrintfLine("250 2.0.0 Message queued for delivery")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
|
||||
state.DATA = nil
|
||||
state.FROM = nil
|
||||
state.RCPT = nil
|
||||
}
|
||||
default:
|
||||
err = textProto.PrintfLine("500 5.5.2 Command not recognized")
|
||||
if err != nil {
|
||||
_ = textProto.PrintfLine("421 4.7.0 Temporary server error")
|
||||
_ = conn.Close()
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
// SenderArgs is a struct that represents the arguments for the Sender
|
||||
type SenderArgs struct {
|
||||
Hostname string
|
||||
EnforceTLS bool
|
||||
}
|
||||
|
||||
// Send sends an email to another server
|
||||
func Send(args SenderArgs, mail *Mail, conn net.Conn, mxHost string) (err error) {
|
||||
textConn := textproto.NewConn(conn)
|
||||
|
||||
err = textConn.PrintfLine("RSET")
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
code, line, err := textConn.ReadCodeLine(0)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if code != 220 {
|
||||
return errors.New("unexpected RSET response - " + line)
|
||||
}
|
||||
|
||||
code, line, err = textConn.ReadCodeLine(0)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if code != 250 {
|
||||
return errors.New("unexpected greeting - " + line)
|
||||
}
|
||||
|
||||
err = textConn.PrintfLine("EHLO %s", args.Hostname)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
code, lines, err := readMultilineCodeResponse(textConn)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if code != 250 {
|
||||
return errors.New("unexpected EHLO response - " + lines)
|
||||
}
|
||||
|
||||
if strings.Contains(lines, "STARTTLS") {
|
||||
err = textConn.PrintfLine("STARTTLS")
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
code, line, err := textConn.ReadCodeLine(0)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if code != 220 {
|
||||
return errors.New("unexpected STARTTLS response - " + line)
|
||||
}
|
||||
|
||||
tlsConn := tls.Client(conn, &tls.Config{
|
||||
ServerName: mxHost,
|
||||
InsecureSkipVerify: false,
|
||||
})
|
||||
|
||||
err = tlsConn.Handshake()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
textConn = textproto.NewConn(tlsConn)
|
||||
|
||||
// Just use HELO, no point using EHLO when we already have all the capabilities
|
||||
// This also gets us out of using readMultilineCodeResponse
|
||||
err = textConn.PrintfLine("HELO %s", args.Hostname)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
code, line, err = textConn.ReadCodeLine(0)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
if code != 250 {
|
||||
return errors.New("unexpected STARTTLS HELO response - " + line)
|
||||
}
|
||||
} else if args.EnforceTLS {
|
||||
return errors.New("STARTTLS not supported")
|
||||
}
|
||||
|
||||
err = textConn.PrintfLine("MAIL FROM:<%s@%s>", mail.From.Name, mail.From.Address)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
code, line, err = textConn.ReadCodeLine(0)
|
||||
fmt.Println(code, line, err)
|
||||
if err != nil {
|
||||
// For some reason the EHLO stuff ends up here
|
||||
fmt.Println("5")
|
||||
return err
|
||||
}
|
||||
|
||||
if code != 250 {
|
||||
return errors.New("unexpected MAIL FROM response - " + line)
|
||||
}
|
||||
|
||||
for _, recipient := range mail.To {
|
||||
err = textConn.PrintfLine("RCPT TO:<%s@%s>", recipient.Name, recipient.Address)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
code, line, err = textConn.ReadCodeLine(0)
|
||||
fmt.Println(code, line, err)
|
||||
if err != nil {
|
||||
fmt.Println("6")
|
||||
return err
|
||||
}
|
||||
|
||||
if code != 250 {
|
||||
return errors.New("unexpected RCPT TO response - " + line)
|
||||
}
|
||||
}
|
||||
|
||||
err = textConn.PrintfLine("DATA")
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
code, line, err = textConn.ReadCodeLine(0)
|
||||
fmt.Println(code, line, err)
|
||||
if err != nil {
|
||||
fmt.Println("7")
|
||||
return err
|
||||
}
|
||||
|
||||
if code != 354 {
|
||||
return errors.New("unexpected DATA response - " + line)
|
||||
}
|
||||
|
||||
writer := textConn.DotWriter()
|
||||
_, err = writer.Write(mail.Data)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
err = writer.Close()
|
||||
if err != nil {
|
||||
return errors.New("failed to close data writer - " + err.Error())
|
||||
}
|
||||
|
||||
code, line, err = textConn.ReadCodeLine(0)
|
||||
fmt.Println(code, line, err)
|
||||
if err != nil {
|
||||
fmt.Println("8")
|
||||
return err
|
||||
}
|
||||
|
||||
if code != 250 {
|
||||
return errors.New("unexpected DATA finish response - " + line + ", your message may have been sent, but it is not guaranteed")
|
||||
}
|
||||
|
||||
err = textConn.PrintfLine("QUIT")
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
code, line, err = textConn.ReadCodeLine(0)
|
||||
fmt.Println(code, line, err)
|
||||
if err != nil {
|
||||
fmt.Println("9")
|
||||
return err
|
||||
}
|
||||
|
||||
if code != 221 {
|
||||
return errors.New("unexpected QUIT response - " + line + ", your message may have been sent, but it is not guaranteed")
|
||||
}
|
||||
|
||||
return
|
||||
}
|
||||
Loading…
Reference in New Issue