mirror of
https://github.com/mjl-/mox.git
synced 2024-12-26 00:13:47 +03:00
move sendmail to separate file
This commit is contained in:
Mechiel Lukkien
parent
317dc78397
commit
5535515fcb
2 changed files with 242 additions and 222 deletions
222
main.go
222
main.go
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@ -1,12 +1,10 @@
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package main
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import (
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"bufio"
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"bytes"
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"context"
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"crypto/ed25519"
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"crypto/rsa"
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"crypto/tls"
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"crypto/x509"
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"encoding/base64"
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"encoding/json"
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@ -16,7 +14,6 @@ import (
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"io"
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"log"
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"net"
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"net/mail"
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"os"
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"path/filepath"
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"strings"
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@ -42,7 +39,6 @@ import (
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"github.com/mjl-/mox/moxvar"
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"github.com/mjl-/mox/mtasts"
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"github.com/mjl-/mox/smtp"
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"github.com/mjl-/mox/smtpclient"
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"github.com/mjl-/mox/spf"
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"github.com/mjl-/mox/store"
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"github.com/mjl-/mox/tlsrpt"
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@ -1990,221 +1986,3 @@ func cmdConfigDescribeSendmail(c *cmd) {
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err := sconf.Describe(os.Stdout, submitconf)
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xcheckf(err, "describe config")
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}
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func cmdSendmail(c *cmd) {
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c.params = "[-Fname] [ignoredflags] [-t] [<message]"
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c.help = `Sendmail is a drop-in replacement for /usr/sbin/sendmail to deliver emails sent by unix processes like cron.
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If invoked as "sendmail", it will act as sendmail for sending messages. Its
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intention is to let processes like cron send emails. Messages are submitted to
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an actual mail server over SMTP. The destination mail server and credentials are
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configured in /etc/moxsubmit.conf, see mox config describe-sendmail. The From
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message header is rewritten to the configured address. When the addressee
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appears to be a local user, because without @, the message is sent to the
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configured default address.
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If submitting an email fails, it is added to a directory moxsubmit.failures in
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the user's home directory.
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Most flags are ignored to fake compatibility with other sendmail
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implementations. A single recipient is required, or the tflag.
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/etc/moxsubmit.conf should be group-readable and not readable by others and this
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binary should be setgid that group:
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groupadd moxsubmit
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install -m 2755 -o root -g moxsubmit mox /usr/sbin/sendmail
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touch /etc/moxsubmit.conf
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chown root:moxsubmit /etc/moxsubmit.conf
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chmod 640 /etc/moxsubmit.conf
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# edit /etc/moxsubmit.conf
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`
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// We are faking that we parse flags, this is non-standard, we want to be lax and ignore most flags.
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args := c.flagArgs
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c.flagArgs = []string{}
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c.Parse() // We still have to call Parse for the usage gathering.
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// Typical cron usage of sendmail:
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// anacron: https://salsa.debian.org/debian/anacron/-/blob/c939c8c80fc9419c11a5e6be5cbe84f03ad332fd/runjob.c#L183
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// cron: https://github.com/vixie/cron/blob/fea7a6c5421f88f034be8eef66a84d8b65b5fbe0/config.h#L41
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var from string
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var tflag bool // If set, we need to take the recipient(s) from the message headers. We only do one recipient, in To.
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o := 0
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for i, s := range args {
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if s == "--" {
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o = i + 1
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break
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}
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if !strings.HasPrefix(s, "-") {
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o = i
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break
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}
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s = s[1:]
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if strings.HasPrefix(s, "F") {
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from = s[1:]
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log.Printf("ignoring -F %q", from) // todo
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} else if s == "t" {
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tflag = true
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}
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o = i + 1
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// Ignore options otherwise.
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// todo: we may want to parse more flags. some invocations may not be about sending a message. for now, we'll assume sendmail is only invoked to send a message.
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}
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args = args[o:]
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// todo: perhaps allow configuration of config file through environment variable? have to keep in mind that mox with setgid moxsubmit would be reading the file.
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const confPath = "/etc/moxsubmit.conf"
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err := sconf.ParseFile(confPath, &submitconf)
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xcheckf(err, "parsing config")
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var recipient string
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if len(args) == 1 && !tflag {
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recipient = args[0]
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if !strings.Contains(recipient, "@") {
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if submitconf.DefaultDestination == "" {
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log.Fatalf("recipient %q has no @ and no default destination configured", recipient)
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}
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recipient = submitconf.DefaultDestination
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} else {
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_, err := smtp.ParseAddress(args[0])
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xcheckf(err, "parsing recipient address")
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}
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} else if !tflag || len(args) != 0 {
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log.Fatalln("need either exactly 1 recipient, or -t")
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}
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// Read message and build message we are going to send. We replace \n
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// with \r\n, and we replace the From header.
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// todo: should we also wrap lines that are too long? perhaps only if this is just text, no multipart?
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var sb strings.Builder
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r := bufio.NewReader(os.Stdin)
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header := true // Whether we are in the header.
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fmt.Fprintf(&sb, "From: <%s>\r\n", submitconf.From)
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var haveTo bool
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for {
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line, err := r.ReadString('\n')
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if err != nil && err != io.EOF {
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xcheckf(err, "reading message")
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}
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if line != "" {
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if !strings.HasSuffix(line, "\n") {
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line += "\n"
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}
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if !strings.HasSuffix(line, "\r\n") {
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line = line[:len(line)-1] + "\r\n"
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}
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if header && line == "\r\n" {
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// Bare \r\n marks end of header.
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if !haveTo {
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line = fmt.Sprintf("To: <%s>\r\n", recipient) + line
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}
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header = false
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} else if header {
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t := strings.SplitN(line, ":", 2)
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if len(t) != 2 {
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log.Fatalf("invalid message, missing colon in header")
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}
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k := strings.ToLower(t[0])
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if k == "from" {
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// We already added a From header.
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if err == io.EOF {
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break
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}
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continue
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} else if tflag && k == "to" {
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if recipient != "" {
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log.Fatalf("only single To header allowed")
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}
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s := strings.TrimSpace(t[1])
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if !strings.Contains(s, "@") {
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if submitconf.DefaultDestination == "" {
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log.Fatalf("recipient %q has no @ and no default destination is configured", s)
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}
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recipient = submitconf.DefaultDestination
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} else {
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addrs, err := mail.ParseAddressList(s)
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xcheckf(err, "parsing To address list")
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if len(addrs) != 1 {
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log.Fatalf("only single address allowed in To header")
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}
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recipient = addrs[0].Address
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}
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}
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if k == "to" {
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haveTo = true
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}
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}
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sb.WriteString(line)
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}
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if err == io.EOF {
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break
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}
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}
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msg := sb.String()
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if recipient == "" {
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log.Fatalf("no recipient")
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}
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// Message seems acceptable. We'll try to deliver it from here. If that fails, we
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// store the message in the users home directory.
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xcheckf := func(err error, format string, args ...any) {
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if err == nil {
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return
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}
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log.Printf("submit failed: %s: %s", fmt.Sprintf(format, args...), err)
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homedir, err := os.UserHomeDir()
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xcheckf(err, "finding homedir for storing message after failed delivery")
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maildir := filepath.Join(homedir, "moxsubmit.failures")
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os.Mkdir(maildir, 0700)
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f, err := os.CreateTemp(maildir, "newmsg.")
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xcheckf(err, "creating temp file for storing message after failed delivery")
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defer func() {
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if f != nil {
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if err := os.Remove(f.Name()); err != nil {
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log.Printf("removing temp file after failure storing failed delivery: %v", err)
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}
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}
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}()
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_, err = f.Write([]byte(msg))
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xcheckf(err, "writing message to temp file after failed delivery")
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name := f.Name()
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err = f.Close()
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xcheckf(err, "closing message in temp file after failed delivery")
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f = nil
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log.Printf("saved message in %s", name)
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os.Exit(1)
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}
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var conn net.Conn
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addr := net.JoinHostPort(submitconf.Host, fmt.Sprintf("%d", submitconf.Port))
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d := net.Dialer{Timeout: 30 * time.Second}
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if submitconf.TLS {
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conn, err = tls.DialWithDialer(&d, "tcp", addr, nil)
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} else {
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conn, err = d.Dial("tcp", addr)
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}
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xcheckf(err, "dial submit server")
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ctx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
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defer cancel()
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tlsMode := smtpclient.TLSStrict
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if !submitconf.STARTTLS {
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tlsMode = smtpclient.TLSSkip
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}
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// todo: should have more auth options, scram-sha-256 at least, perhaps cram-md5 for compatibility as well.
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authLine := fmt.Sprintf("AUTH PLAIN %s", base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("\u0000%s\u0000%s", submitconf.Username, submitconf.Password))))
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mox.Conf.Static.HostnameDomain.ASCII = submitconf.LocalHostname
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client, err := smtpclient.New(ctx, mlog.New("sendmail"), conn, tlsMode, submitconf.Host, authLine)
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xcheckf(err, "open smtp session")
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err = client.Deliver(ctx, submitconf.From, recipient, int64(len(msg)), strings.NewReader(msg), true, false)
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xcheckf(err, "submit message")
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if err := client.Close(); err != nil {
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log.Printf("closing smtp session after message was sent: %v", err)
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}
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}
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242
sendmail.go
Normal file
242
sendmail.go
Normal file
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@ -0,0 +1,242 @@
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package main
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import (
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"bufio"
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"context"
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"crypto/tls"
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"encoding/base64"
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"fmt"
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"io"
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"log"
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"net"
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"net/mail"
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"os"
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"path/filepath"
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"strings"
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"time"
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"github.com/mjl-/sconf"
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"github.com/mjl-/mox/mlog"
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"github.com/mjl-/mox/mox-"
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"github.com/mjl-/mox/smtp"
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"github.com/mjl-/mox/smtpclient"
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)
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func cmdSendmail(c *cmd) {
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c.params = "[-Fname] [ignoredflags] [-t] [<message]"
|
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c.help = `Sendmail is a drop-in replacement for /usr/sbin/sendmail to deliver emails sent by unix processes like cron.
|
||||
|
||||
If invoked as "sendmail", it will act as sendmail for sending messages. Its
|
||||
intention is to let processes like cron send emails. Messages are submitted to
|
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an actual mail server over SMTP. The destination mail server and credentials are
|
||||
configured in /etc/moxsubmit.conf, see mox config describe-sendmail. The From
|
||||
message header is rewritten to the configured address. When the addressee
|
||||
appears to be a local user, because without @, the message is sent to the
|
||||
configured default address.
|
||||
|
||||
If submitting an email fails, it is added to a directory moxsubmit.failures in
|
||||
the user's home directory.
|
||||
|
||||
Most flags are ignored to fake compatibility with other sendmail
|
||||
implementations. A single recipient is required, or the tflag.
|
||||
|
||||
/etc/moxsubmit.conf should be group-readable and not readable by others and this
|
||||
binary should be setgid that group:
|
||||
|
||||
groupadd moxsubmit
|
||||
install -m 2755 -o root -g moxsubmit mox /usr/sbin/sendmail
|
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touch /etc/moxsubmit.conf
|
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chown root:moxsubmit /etc/moxsubmit.conf
|
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chmod 640 /etc/moxsubmit.conf
|
||||
# edit /etc/moxsubmit.conf
|
||||
`
|
||||
|
||||
// We are faking that we parse flags, this is non-standard, we want to be lax and ignore most flags.
|
||||
args := c.flagArgs
|
||||
c.flagArgs = []string{}
|
||||
c.Parse() // We still have to call Parse for the usage gathering.
|
||||
|
||||
// Typical cron usage of sendmail:
|
||||
// anacron: https://salsa.debian.org/debian/anacron/-/blob/c939c8c80fc9419c11a5e6be5cbe84f03ad332fd/runjob.c#L183
|
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// cron: https://github.com/vixie/cron/blob/fea7a6c5421f88f034be8eef66a84d8b65b5fbe0/config.h#L41
|
||||
|
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var from string
|
||||
var tflag bool // If set, we need to take the recipient(s) from the message headers. We only do one recipient, in To.
|
||||
o := 0
|
||||
for i, s := range args {
|
||||
if s == "--" {
|
||||
o = i + 1
|
||||
break
|
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}
|
||||
if !strings.HasPrefix(s, "-") {
|
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o = i
|
||||
break
|
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}
|
||||
s = s[1:]
|
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if strings.HasPrefix(s, "F") {
|
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from = s[1:]
|
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log.Printf("ignoring -F %q", from) // todo
|
||||
} else if s == "t" {
|
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tflag = true
|
||||
}
|
||||
o = i + 1
|
||||
// Ignore options otherwise.
|
||||
// todo: we may want to parse more flags. some invocations may not be about sending a message. for now, we'll assume sendmail is only invoked to send a message.
|
||||
}
|
||||
args = args[o:]
|
||||
|
||||
// todo: perhaps allow configuration of config file through environment variable? have to keep in mind that mox with setgid moxsubmit would be reading the file.
|
||||
const confPath = "/etc/moxsubmit.conf"
|
||||
err := sconf.ParseFile(confPath, &submitconf)
|
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xcheckf(err, "parsing config")
|
||||
|
||||
var recipient string
|
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if len(args) == 1 && !tflag {
|
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recipient = args[0]
|
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if !strings.Contains(recipient, "@") {
|
||||
if submitconf.DefaultDestination == "" {
|
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log.Fatalf("recipient %q has no @ and no default destination configured", recipient)
|
||||
}
|
||||
recipient = submitconf.DefaultDestination
|
||||
} else {
|
||||
_, err := smtp.ParseAddress(args[0])
|
||||
xcheckf(err, "parsing recipient address")
|
||||
}
|
||||
} else if !tflag || len(args) != 0 {
|
||||
log.Fatalln("need either exactly 1 recipient, or -t")
|
||||
}
|
||||
|
||||
// Read message and build message we are going to send. We replace \n
|
||||
// with \r\n, and we replace the From header.
|
||||
// todo: should we also wrap lines that are too long? perhaps only if this is just text, no multipart?
|
||||
var sb strings.Builder
|
||||
r := bufio.NewReader(os.Stdin)
|
||||
header := true // Whether we are in the header.
|
||||
fmt.Fprintf(&sb, "From: <%s>\r\n", submitconf.From)
|
||||
var haveTo bool
|
||||
for {
|
||||
line, err := r.ReadString('\n')
|
||||
if err != nil && err != io.EOF {
|
||||
xcheckf(err, "reading message")
|
||||
}
|
||||
if line != "" {
|
||||
if !strings.HasSuffix(line, "\n") {
|
||||
line += "\n"
|
||||
}
|
||||
if !strings.HasSuffix(line, "\r\n") {
|
||||
line = line[:len(line)-1] + "\r\n"
|
||||
}
|
||||
if header && line == "\r\n" {
|
||||
// Bare \r\n marks end of header.
|
||||
if !haveTo {
|
||||
line = fmt.Sprintf("To: <%s>\r\n", recipient) + line
|
||||
}
|
||||
header = false
|
||||
} else if header {
|
||||
t := strings.SplitN(line, ":", 2)
|
||||
if len(t) != 2 {
|
||||
log.Fatalf("invalid message, missing colon in header")
|
||||
}
|
||||
k := strings.ToLower(t[0])
|
||||
if k == "from" {
|
||||
// We already added a From header.
|
||||
if err == io.EOF {
|
||||
break
|
||||
}
|
||||
continue
|
||||
} else if tflag && k == "to" {
|
||||
if recipient != "" {
|
||||
log.Fatalf("only single To header allowed")
|
||||
}
|
||||
s := strings.TrimSpace(t[1])
|
||||
if !strings.Contains(s, "@") {
|
||||
if submitconf.DefaultDestination == "" {
|
||||
log.Fatalf("recipient %q has no @ and no default destination is configured", s)
|
||||
}
|
||||
recipient = submitconf.DefaultDestination
|
||||
} else {
|
||||
addrs, err := mail.ParseAddressList(s)
|
||||
xcheckf(err, "parsing To address list")
|
||||
if len(addrs) != 1 {
|
||||
log.Fatalf("only single address allowed in To header")
|
||||
}
|
||||
recipient = addrs[0].Address
|
||||
}
|
||||
}
|
||||
if k == "to" {
|
||||
haveTo = true
|
||||
}
|
||||
}
|
||||
sb.WriteString(line)
|
||||
}
|
||||
if err == io.EOF {
|
||||
break
|
||||
}
|
||||
}
|
||||
msg := sb.String()
|
||||
|
||||
if recipient == "" {
|
||||
log.Fatalf("no recipient")
|
||||
}
|
||||
|
||||
// Message seems acceptable. We'll try to deliver it from here. If that fails, we
|
||||
// store the message in the users home directory.
|
||||
|
||||
xcheckf := func(err error, format string, args ...any) {
|
||||
if err == nil {
|
||||
return
|
||||
}
|
||||
log.Printf("submit failed: %s: %s", fmt.Sprintf(format, args...), err)
|
||||
homedir, err := os.UserHomeDir()
|
||||
xcheckf(err, "finding homedir for storing message after failed delivery")
|
||||
maildir := filepath.Join(homedir, "moxsubmit.failures")
|
||||
os.Mkdir(maildir, 0700)
|
||||
f, err := os.CreateTemp(maildir, "newmsg.")
|
||||
xcheckf(err, "creating temp file for storing message after failed delivery")
|
||||
defer func() {
|
||||
if f != nil {
|
||||
if err := os.Remove(f.Name()); err != nil {
|
||||
log.Printf("removing temp file after failure storing failed delivery: %v", err)
|
||||
}
|
||||
}
|
||||
}()
|
||||
_, err = f.Write([]byte(msg))
|
||||
xcheckf(err, "writing message to temp file after failed delivery")
|
||||
name := f.Name()
|
||||
err = f.Close()
|
||||
xcheckf(err, "closing message in temp file after failed delivery")
|
||||
f = nil
|
||||
log.Printf("saved message in %s", name)
|
||||
os.Exit(1)
|
||||
}
|
||||
|
||||
var conn net.Conn
|
||||
addr := net.JoinHostPort(submitconf.Host, fmt.Sprintf("%d", submitconf.Port))
|
||||
d := net.Dialer{Timeout: 30 * time.Second}
|
||||
if submitconf.TLS {
|
||||
conn, err = tls.DialWithDialer(&d, "tcp", addr, nil)
|
||||
} else {
|
||||
conn, err = d.Dial("tcp", addr)
|
||||
}
|
||||
xcheckf(err, "dial submit server")
|
||||
|
||||
ctx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
|
||||
defer cancel()
|
||||
tlsMode := smtpclient.TLSStrict
|
||||
if !submitconf.STARTTLS {
|
||||
tlsMode = smtpclient.TLSSkip
|
||||
}
|
||||
// todo: should have more auth options, scram-sha-256 at least, perhaps cram-md5 for compatibility as well.
|
||||
authLine := fmt.Sprintf("AUTH PLAIN %s", base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf("\u0000%s\u0000%s", submitconf.Username, submitconf.Password))))
|
||||
mox.Conf.Static.HostnameDomain.ASCII = submitconf.LocalHostname
|
||||
client, err := smtpclient.New(ctx, mlog.New("sendmail"), conn, tlsMode, submitconf.Host, authLine)
|
||||
xcheckf(err, "open smtp session")
|
||||
|
||||
err = client.Deliver(ctx, submitconf.From, recipient, int64(len(msg)), strings.NewReader(msg), true, false)
|
||||
xcheckf(err, "submit message")
|
||||
|
||||
if err := client.Close(); err != nil {
|
||||
log.Printf("closing smtp session after message was sent: %v", err)
|
||||
}
|
||||
}
|
||||
Loading…
Reference in a new issue