mox/localserve.go
Mechiel Lukkien 28fae96a9b
make mox compile on windows, without "mox serve" but with working "mox localserve"
getting mox to compile required changing code in only a few places where
package "syscall" was used: for accessing file access times and for umask
handling. an open problem is how to start a process as an unprivileged user on
windows.  that's why "mox serve" isn't implemented yet. and just finding a way
to implement it now may not be good enough in the near future: we may want to
starting using a more complete privilege separation approach, with a process
handling sensitive tasks (handling private keys, authentication), where we may
want to pass file descriptors between processes. how would that work on
windows?

anyway, getting mox to compile for windows doesn't mean it works properly on
windows. the largest issue: mox would normally open a file, rename or remove
it, and finally close it. this happens during message delivery. that doesn't
work on windows, the rename/remove would fail because the file is still open.
so this commit swaps many "remove" and "close" calls. renames are a longer
story: message delivery had two ways to deliver: with "consuming" the
(temporary) message file (which would rename it to its final destination), and
without consuming (by hardlinking the file, falling back to copying). the last
delivery to a recipient of a message (and the only one in the common case of a
single recipient) would consume the message, and the earlier recipients would
not.  during delivery, the already open message file was used, to parse the
message.  we still want to use that open message file, and the caller now stays
responsible for closing it, but we no longer try to rename (consume) the file.
we always hardlink (or copy) during delivery (this works on windows), and the
caller is responsible for closing and removing (in that order) the original
temporary file. this does cost one syscall more. but it makes the delivery code
(responsibilities) a bit simpler.

there is one more obvious issue: the file system path separator. mox already
used the "filepath" package to join paths in many places, but not everywhere.
and it still used strings with slashes for local file access. with this commit,
the code now uses filepath.FromSlash for path strings with slashes, uses
"filepath" in a few more places where it previously didn't. also switches from
"filepath" to regular "path" package when handling mailbox names in a few
places, because those always use forward slashes, regardless of local file
system conventions.  windows can handle forward slashes when opening files, so
test code that passes path strings with forward slashes straight to go stdlib
file i/o functions are left unchanged to reduce code churn. the regular
non-test code, or test code that uses path strings in places other than
standard i/o functions, does have the paths converted for consistent paths
(otherwise we would end up with paths with mixed forward/backward slashes in
log messages).

windows cannot dup a listening socket. for "mox localserve", it isn't
important, and we can work around the issue. the current approach for "mox
serve" (forking a process and passing file descriptors of listening sockets on
"privileged" ports) won't work on windows. perhaps it isn't needed on windows,
and any user can listen on "privileged" ports? that would be welcome.

on windows, os.Open cannot open a directory, so we cannot call Sync on it after
message delivery. a cursory internet search indicates that directories cannot
be synced on windows. the story is probably much more nuanced than that, with
long deep technical details/discussions/disagreement/confusion, like on unix.
for "mox localserve" we can get away with making syncdir a no-op.
2023-10-14 10:54:07 +02:00

443 lines
14 KiB
Go

package main
import (
"bytes"
"context"
"crypto/ecdsa"
"crypto/elliptic"
cryptorand "crypto/rand"
"crypto/x509"
"crypto/x509/pkix"
"encoding/pem"
"fmt"
golog "log"
"math/big"
"net"
"os"
"os/signal"
"path/filepath"
"syscall"
"time"
"golang.org/x/crypto/bcrypt"
"github.com/mjl-/sconf"
"github.com/mjl-/mox/config"
"github.com/mjl-/mox/junk"
"github.com/mjl-/mox/mlog"
"github.com/mjl-/mox/mox-"
"github.com/mjl-/mox/moxvar"
"github.com/mjl-/mox/queue"
"github.com/mjl-/mox/smtpserver"
"github.com/mjl-/mox/store"
)
func cmdLocalserve(c *cmd) {
c.help = `Start a local SMTP/IMAP server that accepts all messages, useful when testing/developing software that sends email.
Localserve starts mox with a configuration suitable for local email-related
software development/testing. It listens for SMTP/Submission(s), IMAP(s) and
HTTP(s), on the regular port numbers + 1000.
Data is stored in the system user's configuration directory under
"mox-localserve", e.g. $HOME/.config/mox-localserve/ on linux, but can be
overridden with the -dir flag. If the directory does not yet exist, it is
automatically initialized with configuration files, an account with email
address mox@localhost and password moxmoxmox, and a newly generated self-signed
TLS certificate.
All incoming email to any address is accepted (if checks pass), unless the
recipient localpart ends with:
- "temperror": fail with a temporary error code
- "permerror": fail with a permanent error code
- [45][0-9][0-9]: fail with the specific error code
- "timeout": no response (for an hour)
If the localpart begins with "mailfrom" or "rcptto", the error is returned
during those commands instead of during "data".
`
golog.SetFlags(0)
userConfDir, _ := os.UserConfigDir()
if userConfDir == "" {
userConfDir = "."
}
var dir, ip string
c.flag.StringVar(&dir, "dir", filepath.Join(userConfDir, "mox-localserve"), "configuration storage directory")
c.flag.StringVar(&ip, "ip", "", "serve on this ip instead of default 127.0.0.1 and ::1. only used when writing configuration, at first launch.")
args := c.Parse()
if len(args) != 0 {
c.Usage()
}
log := mlog.New("localserve")
mox.FilesImmediate = true
// Load config, creating a new one if needed.
var existingConfig bool
if _, err := os.Stat(dir); err != nil && os.IsNotExist(err) {
err := writeLocalConfig(log, dir, ip)
if err != nil {
log.Fatalx("creating mox localserve config", err, mlog.Field("dir", dir))
}
} else if err != nil {
log.Fatalx("stat config dir", err, mlog.Field("dir", dir))
} else if err := localLoadConfig(log, dir); err != nil {
log.Fatalx("loading mox localserve config (hint: when creating a new config with -dir, the directory must not yet exist)", err, mlog.Field("dir", dir))
} else if ip != "" {
log.Fatal("can only use -ip when writing a new config file")
} else {
existingConfig = true
}
if level, ok := mlog.Levels[loglevel]; loglevel != "" && ok {
mox.Conf.Log[""] = level
mlog.SetConfig(mox.Conf.Log)
} else if loglevel != "" && !ok {
log.Fatal("unknown loglevel", mlog.Field("loglevel", loglevel))
}
// Initialize receivedid.
recvidbuf, err := os.ReadFile(filepath.Join(dir, "receivedid.key"))
if err == nil && len(recvidbuf) != 16+8 {
err = fmt.Errorf("bad length %d, need 16+8", len(recvidbuf))
}
if err != nil {
log.Errorx("reading receivedid.key", err)
recvidbuf = make([]byte, 16+8)
_, err := cryptorand.Read(recvidbuf)
if err != nil {
log.Fatalx("read random recvid key", err)
}
}
if err := mox.ReceivedIDInit(recvidbuf[:16], recvidbuf[16:]); err != nil {
log.Fatalx("init receivedid", err)
}
// Make smtp server accept all email and deliver to account "mox".
smtpserver.Localserve = true
// Tell queue it shouldn't be queuing/delivering.
queue.Localserve = true
const mtastsdbRefresher = false
const skipForkExec = true
if err := start(mtastsdbRefresher, skipForkExec); err != nil {
log.Fatalx("starting mox", err)
}
golog.Printf("mox, version %s", moxvar.Version)
golog.Print("")
golog.Printf("the default user is mox@localhost, with password moxmoxmox")
golog.Printf("the default admin password is moxadmin")
golog.Printf("port numbers are those common for the services + 1000")
golog.Printf("tls uses generated self-signed certificate %s", filepath.Join(dir, "localhost.crt"))
golog.Printf("all incoming email to any address is accepted (if checks pass), unless the recipient localpart ends with:")
golog.Print("")
golog.Printf(`- "temperror": fail with a temporary error code.`)
golog.Printf(`- "permerror": fail with a permanent error code.`)
golog.Printf(`- [45][0-9][0-9]: fail with the specific error code.`)
golog.Printf(`- "timeout": no response (for an hour).`)
golog.Print("")
golog.Printf(`if the localpart begins with "mailfrom" or "rcptto", the error is returned during those commands instead of during "data"`)
golog.Print("")
golog.Print(" smtp://localhost:1025 - receive email")
golog.Print("smtps://mox%40localhost:moxmoxmox@localhost:1465 - send email")
golog.Print(" smtp://mox%40localhost:moxmoxmox@localhost:1587 - send email (without tls)")
golog.Print("imaps://mox%40localhost:moxmoxmox@localhost:1993 - read email")
golog.Print(" imap://mox%40localhost:moxmoxmox@localhost:1143 - read email (without tls)")
golog.Print("https://mox%40localhost:moxmoxmox@localhost:1443/account/ - account https")
golog.Print(" http://mox%40localhost:moxmoxmox@localhost:1080/account/ - account http (without tls)")
golog.Print("https://mox%40localhost:moxmoxmox@localhost:1443/webmail/ - webmail https")
golog.Print(" http://mox%40localhost:moxmoxmox@localhost:1080/webmail/ - webmail http (without tls)")
golog.Print("https://admin:moxadmin@localhost:1443/admin/ - admin https")
golog.Print(" http://admin:moxadmin@localhost:1080/admin/ - admin http (without tls)")
golog.Print("")
if existingConfig {
golog.Printf("serving from existing config dir %s/", dir)
golog.Printf("if urls above don't work, consider resetting by removing config dir")
} else {
golog.Printf("serving from newly created config dir %s/", dir)
}
ctlpath := mox.DataDirPath("ctl")
_ = os.Remove(ctlpath)
ctl, err := net.Listen("unix", ctlpath)
if err != nil {
log.Fatalx("listen on ctl unix domain socket", err)
}
go func() {
for {
conn, err := ctl.Accept()
if err != nil {
log.Printx("accept for ctl", err)
continue
}
cid := mox.Cid()
ctx := context.WithValue(mox.Context, mlog.CidKey, cid)
go servectl(ctx, log.WithCid(cid), conn, func() { shutdown(log) })
}
}()
// Graceful shutdown.
sigc := make(chan os.Signal, 1)
signal.Notify(sigc, os.Interrupt, syscall.SIGTERM)
sig := <-sigc
log.Print("shutting down, waiting max 3s for existing connections", mlog.Field("signal", sig))
shutdown(log)
if num, ok := sig.(syscall.Signal); ok {
os.Exit(int(num))
} else {
os.Exit(1)
}
}
func writeLocalConfig(log *mlog.Log, dir, ip string) (rerr error) {
defer func() {
x := recover()
if x != nil {
if err, ok := x.(error); ok {
rerr = err
}
}
if rerr != nil {
err := os.RemoveAll(dir)
log.Check(err, "removing config directory", mlog.Field("dir", dir))
}
}()
xcheck := func(err error, msg string) {
if err != nil {
panic(fmt.Errorf("%s: %s", msg, err))
}
}
os.MkdirAll(dir, 0770)
// Generate key and self-signed certificate for use with TLS.
privKey, err := ecdsa.GenerateKey(elliptic.P256(), cryptorand.Reader)
xcheck(err, "generating ecdsa key for self-signed certificate")
privKeyDER, err := x509.MarshalPKCS8PrivateKey(privKey)
xcheck(err, "marshal private key to pkcs8")
privBlock := &pem.Block{
Type: "PRIVATE KEY",
Headers: map[string]string{
"Note": "ECDSA key generated by mox localserve for self-signed certificate.",
},
Bytes: privKeyDER,
}
var privPEM bytes.Buffer
err = pem.Encode(&privPEM, privBlock)
xcheck(err, "pem-encoding private key")
err = os.WriteFile(filepath.Join(dir, "localhost.key"), privPEM.Bytes(), 0660)
xcheck(err, "writing private key for self-signed certificate")
// Now the certificate.
template := &x509.Certificate{
SerialNumber: big.NewInt(time.Now().Unix()), // Required field.
DNSNames: []string{"localhost"},
NotBefore: time.Now().Add(-time.Hour),
NotAfter: time.Now().Add(4 * 365 * 24 * time.Hour),
Issuer: pkix.Name{
Organization: []string{"mox localserve"},
},
Subject: pkix.Name{
Organization: []string{"mox localserve"},
CommonName: "localhost",
},
}
certDER, err := x509.CreateCertificate(cryptorand.Reader, template, template, privKey.Public(), privKey)
xcheck(err, "making self-signed certificate")
pubBlock := &pem.Block{
Type: "CERTIFICATE",
// Comments (header) would cause failure to parse the certificate when we load the config.
Bytes: certDER,
}
var crtPEM bytes.Buffer
err = pem.Encode(&crtPEM, pubBlock)
xcheck(err, "pem-encoding self-signed certificate")
err = os.WriteFile(filepath.Join(dir, "localhost.crt"), crtPEM.Bytes(), 0660)
xcheck(err, "writing self-signed certificate")
// Write adminpasswd.
adminpw := "moxadmin"
adminpwhash, err := bcrypt.GenerateFromPassword([]byte(adminpw), bcrypt.DefaultCost)
xcheck(err, "generating hash for admin password")
err = os.WriteFile(filepath.Join(dir, "adminpasswd"), adminpwhash, 0660)
xcheck(err, "writing adminpasswd file")
// Write mox.conf.
ips := []string{"127.0.0.1", "::1"}
if ip != "" {
ips = []string{ip}
}
local := config.Listener{
IPs: ips,
TLS: &config.TLS{
KeyCerts: []config.KeyCert{
{
CertFile: "localhost.crt",
KeyFile: "localhost.key",
},
},
},
}
local.SMTP.Enabled = true
local.SMTP.Port = 1025
local.Submission.Enabled = true
local.Submission.Port = 1587
local.Submission.NoRequireSTARTTLS = true
local.Submissions.Enabled = true
local.Submissions.Port = 1465
local.IMAP.Enabled = true
local.IMAP.Port = 1143
local.IMAP.NoRequireSTARTTLS = true
local.IMAPS.Enabled = true
local.IMAPS.Port = 1993
local.AccountHTTP.Enabled = true
local.AccountHTTP.Port = 1080
local.AccountHTTP.Path = "/account/"
local.AccountHTTPS.Enabled = true
local.AccountHTTPS.Port = 1443
local.AccountHTTPS.Path = "/account/"
local.WebmailHTTP.Enabled = true
local.WebmailHTTP.Port = 1080
local.WebmailHTTP.Path = "/webmail/"
local.WebmailHTTPS.Enabled = true
local.WebmailHTTPS.Port = 1443
local.WebmailHTTPS.Path = "/webmail/"
local.AdminHTTP.Enabled = true
local.AdminHTTP.Port = 1080
local.AdminHTTPS.Enabled = true
local.AdminHTTPS.Port = 1443
local.MetricsHTTP.Enabled = true
local.MetricsHTTP.Port = 1081
local.WebserverHTTP.Enabled = true
local.WebserverHTTP.Port = 1080
local.WebserverHTTPS.Enabled = true
local.WebserverHTTPS.Port = 1443
uid := os.Getuid()
if uid < 0 {
uid = 1 // For windows.
}
static := config.Static{
DataDir: ".",
LogLevel: "traceauth",
Hostname: "localhost",
User: fmt.Sprintf("%d", uid),
AdminPasswordFile: "adminpasswd",
Pedantic: true,
Listeners: map[string]config.Listener{
"local": local,
},
}
tlsca := struct {
AdditionalToSystem bool `sconf:"optional"`
CertFiles []string `sconf:"optional"`
}{true, []string{"localhost.crt"}}
static.TLS.CA = &tlsca
static.Postmaster.Account = "mox"
static.Postmaster.Mailbox = "Inbox"
var moxconfBuf bytes.Buffer
err = sconf.WriteDocs(&moxconfBuf, static)
xcheck(err, "making mox.conf")
err = os.WriteFile(filepath.Join(dir, "mox.conf"), moxconfBuf.Bytes(), 0660)
xcheck(err, "writing mox.conf")
// Write domains.conf.
acc := config.Account{
RejectsMailbox: "Rejects",
Destinations: map[string]config.Destination{
"mox@localhost": {},
},
}
acc.AutomaticJunkFlags.Enabled = true
acc.AutomaticJunkFlags.JunkMailboxRegexp = "^(junk|spam)"
acc.AutomaticJunkFlags.NeutralMailboxRegexp = "^(inbox|neutral|postmaster|dmarc|tlsrpt|rejects)"
acc.JunkFilter = &config.JunkFilter{
Threshold: 0.95,
Params: junk.Params{
Onegrams: true,
MaxPower: .01,
TopWords: 10,
IgnoreWords: .1,
RareWords: 2,
},
}
dynamic := config.Dynamic{
Domains: map[string]config.Domain{
"localhost": {
LocalpartCatchallSeparator: "+",
},
},
Accounts: map[string]config.Account{
"mox": acc,
},
WebHandlers: []config.WebHandler{
{
LogName: "workdir",
Domain: "localhost",
PathRegexp: "^/workdir/",
DontRedirectPlainHTTP: true,
WebStatic: &config.WebStatic{
StripPrefix: "/workdir/",
Root: ".",
ListFiles: true,
},
},
},
}
var domainsconfBuf bytes.Buffer
err = sconf.WriteDocs(&domainsconfBuf, dynamic)
xcheck(err, "making domains.conf")
err = os.WriteFile(filepath.Join(dir, "domains.conf"), domainsconfBuf.Bytes(), 0660)
xcheck(err, "writing domains.conf")
// Write receivedid.key.
recvidbuf := make([]byte, 16+8)
_, err = cryptorand.Read(recvidbuf)
xcheck(err, "reading random recvid data")
err = os.WriteFile(filepath.Join(dir, "receivedid.key"), recvidbuf, 0660)
xcheck(err, "writing receivedid.key")
// Load config, so we can access the account.
err = localLoadConfig(log, dir)
xcheck(err, "loading config")
// Set password on account.
a, _, err := store.OpenEmail("mox@localhost")
xcheck(err, "opening account to set password")
password := "moxmoxmox"
err = a.SetPassword(password)
xcheck(err, "setting password")
err = a.Close()
xcheck(err, "closing account")
golog.Printf("config created in %s", dir)
return nil
}
func localLoadConfig(log *mlog.Log, dir string) error {
mox.ConfigStaticPath = filepath.Join(dir, "mox.conf")
mox.ConfigDynamicPath = filepath.Join(dir, "domains.conf")
errs := mox.LoadConfig(context.Background(), true, false)
if len(errs) > 1 {
log.Error("loading config generated config file: multiple errors")
for _, err := range errs {
log.Errorx("config error", err)
}
return fmt.Errorf("stopping after multiple config errors")
} else if len(errs) == 1 {
return fmt.Errorf("loading config file: %v", errs[0])
}
return nil
}