+// mailpopbox
+// Copyright 2020 Blue Static <https://www.bluestatic.org>
+// This program is free software licensed under the GNU General Public License,
+// version 3.0. The full text of the license can be found in LICENSE.txt.
+// SPDX-License-Identifier: GPL-3.0-only
+
package main
import (
+ "bytes"
"crypto/tls"
"fmt"
"net"
"net/mail"
+ "os"
+ "path"
+ "regexp"
+
+ "go.uber.org/zap"
"src.bluestatic.org/mailpopbox/smtp"
)
-func runSMTPServer(config Config) <-chan error {
+var sendAsSubject = regexp.MustCompile(`(?i)\[sendas:\s*([a-zA-Z0-9\.\-_]+)\]`)
+
+func runSMTPServer(config Config, log *zap.Logger) <-chan ServerControlMessage {
server := smtpServer{
- config: config,
- rc: make(chan error),
+ config: config,
+ controlChan: make(chan ServerControlMessage),
+ log: log.With(zap.String("server", "smtp")),
}
+ server.mta = smtp.NewDefaultMTA(&server, server.log)
go server.run()
- return server.rc
+ return server.controlChan
}
type smtpServer struct {
- config Config
- rc chan error
+ config Config
+ tlsConfig *tls.Config
+
+ mta smtp.MTA
+
+ log *zap.Logger
+
+ controlChan chan ServerControlMessage
}
func (server *smtpServer) run() {
- l, err := net.Listen("tcp", fmt.Sprintf(":%d", server.config.SMTPPort))
+ if !server.loadTLSConfig() {
+ return
+ }
+
+ addr := fmt.Sprintf(":%d", server.config.SMTPPort)
+ server.log.Info("starting server", zap.String("address", addr))
+
+ l, err := net.Listen("tcp", addr)
if err != nil {
- server.rc <- err
+ server.log.Error("listen", zap.Error(err))
+ server.controlChan <- ServerControlFatalError
return
}
+ connChan := make(chan net.Conn)
+ go RunAcceptLoop(l, connChan, server.log)
+
+ reloadChan := CreateReloadSignal()
+
for {
- conn, err := l.Accept()
- if err != nil {
- server.rc <- err
- return
+ select {
+ case <-reloadChan:
+ if !server.loadTLSConfig() {
+ return
+ }
+ case conn, ok := <-connChan:
+ if ok {
+ go smtp.AcceptConnection(conn, server, server.log)
+ } else {
+ break
+ }
}
+ }
+}
- go smtp.AcceptConnection(conn, server)
+func (server *smtpServer) loadTLSConfig() bool {
+ var err error
+ server.tlsConfig, err = server.config.GetTLSConfig()
+ if err != nil {
+ server.log.Error("failed to configure TLS", zap.Error(err))
+ server.controlChan <- ServerControlFatalError
+ return false
}
+ server.log.Info("loaded TLS config")
+ return true
}
func (server *smtpServer) Name() string {
}
func (server *smtpServer) TLSConfig() *tls.Config {
- return nil
+ return server.tlsConfig
}
func (server *smtpServer) VerifyAddress(addr mail.Address) smtp.ReplyLine {
+ s := server.configForAddress(addr)
+ if s == nil {
+ return smtp.ReplyBadMailbox
+ }
+ for _, blocked := range s.BlockedAddresses {
+ if blocked == addr.Address {
+ return smtp.ReplyMailboxUnallowed
+ }
+ }
return smtp.ReplyOK
}
-func (server *smtpServer) OnEHLO() *smtp.ReplyLine {
+func (server *smtpServer) Authenticate(authz, authc, passwd string) bool {
+ authcAddr, err := mail.ParseAddress(authc)
+ if err != nil {
+ return false
+ }
+
+ authzAddr, err := mail.ParseAddress(authz)
+ if authz != "" && err != nil {
+ return false
+ }
+
+ domain := smtp.DomainForAddress(*authcAddr)
+ for _, s := range server.config.Servers {
+ if domain == s.Domain {
+ authOk := authc == MailboxAccount+s.Domain && passwd == s.MailboxPassword
+ if authzAddr != nil {
+ authOk = authOk && smtp.DomainForAddress(*authzAddr) == domain
+ }
+ return authOk
+ }
+ }
+ return false
+}
+
+func (server *smtpServer) DeliverMessage(en smtp.Envelope) *smtp.ReplyLine {
+ maildrop := server.maildropForAddress(en.RcptTo[0])
+ if maildrop == "" {
+ server.log.Error("faild to open maildrop to deliver message", zap.String("id", en.ID))
+ return &smtp.ReplyBadMailbox
+ }
+
+ f, err := os.Create(path.Join(maildrop, en.ID+".msg"))
+ if err != nil {
+ server.log.Error("failed to create message file", zap.String("id", en.ID), zap.Error(err))
+ return &smtp.ReplyBadMailbox
+ }
+
+ smtp.WriteEnvelopeForDelivery(f, en)
+ f.Close()
return nil
}
-func (server *smtpServer) OnMessageDelivered(en smtp.Envelope) *smtp.ReplyLine {
- fmt.Printf("MSG: %#v\n%s\n", en, string(en.Data))
+func (server *smtpServer) configForAddress(addr mail.Address) *Server {
+ domain := smtp.DomainForAddress(addr)
+ for _, s := range server.config.Servers {
+ if domain == s.Domain {
+ return &s
+ }
+ }
return nil
}
+
+func (server *smtpServer) maildropForAddress(addr mail.Address) string {
+ s := server.configForAddress(addr)
+ if s != nil {
+ return s.MaildropPath
+ }
+ return ""
+}
+
+func (server *smtpServer) RelayMessage(en smtp.Envelope, authc string) {
+ go func() {
+ log := server.log.With(zap.String("id", en.ID))
+ server.handleSendAs(log, &en, authc)
+ server.mta.RelayMessage(en)
+ }()
+}
+
+func (server *smtpServer) handleSendAs(log *zap.Logger, en *smtp.Envelope, authc string) {
+ // Find the separator between the message header and body.
+ headerIdx := bytes.Index(en.Data, []byte("\n\n"))
+ if headerIdx == -1 {
+ log.Error("send-as: could not find headers index")
+ return
+ }
+
+ var buf bytes.Buffer
+
+ headers := bytes.SplitAfter(en.Data[:headerIdx], []byte("\n"))
+
+ var fromIdx, subjectIdx int
+ for i, header := range headers {
+ if bytes.HasPrefix(header, []byte("From:")) {
+ fromIdx = i
+ continue
+ }
+ if bytes.HasPrefix(header, []byte("Subject:")) {
+ subjectIdx = i
+ continue
+ }
+ }
+
+ if subjectIdx == -1 {
+ log.Error("send-as: could not find Subject header")
+ return
+ }
+ if fromIdx == -1 {
+ log.Error("send-as: could not find From header")
+ return
+ }
+
+ sendAs := sendAsSubject.FindSubmatchIndex(headers[subjectIdx])
+ if sendAs == nil {
+ // No send-as modification.
+ return
+ }
+
+ // Submatch 0 is the whole sendas magic. Submatch 1 is the address prefix.
+ sendAsUser := headers[subjectIdx][sendAs[2]:sendAs[3]]
+ sendAsAddress := string(sendAsUser) + "@" + smtp.DomainForAddressString(authc)
+
+ log.Info("handling send-as", zap.String("address", sendAsAddress))
+
+ for i, header := range headers {
+ if i == subjectIdx {
+ buf.Write(header[:sendAs[0]])
+ buf.Write(header[sendAs[1]:])
+ } else if i == fromIdx {
+ addressStart := bytes.LastIndexByte(header, byte('<'))
+ buf.Write(header[:addressStart+1])
+ buf.WriteString(sendAsAddress)
+ buf.WriteString(">\n")
+ } else {
+ buf.Write(header)
+ }
+ }
+
+ buf.Write(en.Data[headerIdx:])
+
+ en.Data = buf.Bytes()
+ en.MailFrom.Address = sendAsAddress
+}
https://src.bluestatic.org / mailpopbox.git / blobdiff