mox/http/web.go
Mechiel Lukkien ad51ffc365
make account web page configurable separately from admin, add http auth rate limiting
ideally both account & admin web pages should be on non-public ips (e.g. a
wireguard tunnel). but during setup, users may not have that set up, and they
may want to configure the admin/account pages on their public ip's. the auth
rate limiting should make it less of issue.

users can now also only put the account web page publicly available. useful for
if you're the admin and you have a vpn connection, but your other/external
users do not have a vpn into your mail server. to make the account page more
easily findable, the http root serves the account page. the admin page is still
at /admin/, to prevent clash with potential account pages, but if no account
page is present, you are helpfully redirected from / to /admin/.

this also adds a prometheus metric counting how often auth attempts have been
rate limited.
2023-02-13 13:53:47 +01:00

232 lines
7.5 KiB
Go

// Package http provides HTTP listeners/servers, for
// autoconfiguration/autodiscovery, the account and admin web interface and
// MTA-STS policies.
package http
import (
"crypto/tls"
"fmt"
golog "log"
"net"
"net/http"
"strings"
"time"
_ "net/http/pprof"
"github.com/prometheus/client_golang/prometheus/promhttp"
"github.com/mjl-/mox/config"
"github.com/mjl-/mox/dns"
"github.com/mjl-/mox/mlog"
"github.com/mjl-/mox/mox-"
)
var xlog = mlog.New("http")
// Set some http headers that should prevent potential abuse. Better safe than sorry.
func safeHeaders(fn http.HandlerFunc) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
h := w.Header()
h.Set("X-Frame-Options", "deny")
h.Set("X-Content-Type-Options", "nosniff")
h.Set("Content-Security-Policy", "default-src 'self' 'unsafe-inline' data:")
h.Set("Referrer-Policy", "same-origin")
fn(w, r)
}
}
// ListenAndServe starts listeners for HTTP, including those required for ACME to
// generate TLS certificates.
func ListenAndServe() {
type serve struct {
kinds []string
tlsConfig *tls.Config
mux *http.ServeMux
}
for name, l := range mox.Conf.Static.Listeners {
portServe := map[int]serve{}
var ensureServe func(https bool, port int, kind string) serve
ensureServe = func(https bool, port int, kind string) serve {
s, ok := portServe[port]
if !ok {
s = serve{nil, nil, &http.ServeMux{}}
}
s.kinds = append(s.kinds, kind)
if https && port == 443 && l.TLS.ACME != "" {
s.tlsConfig = l.TLS.ACMEConfig
} else if https {
s.tlsConfig = l.TLS.Config
if l.TLS.ACME != "" {
ensureServe(true, 443, "acme-tls-alpn-01")
}
}
portServe[port] = s
return s
}
if l.SMTP.Enabled && !l.SMTP.NoSTARTTLS || l.Submissions.Enabled || l.IMAPS.Enabled {
ensureServe(true, 443, "acme-tls-alpn01")
}
if l.AccountHTTP.Enabled {
srv := ensureServe(false, config.Port(l.AccountHTTP.Port, 80), "account-http")
srv.mux.HandleFunc("/", safeHeaders(accountHandle))
}
if l.AccountHTTPS.Enabled {
srv := ensureServe(true, config.Port(l.AccountHTTP.Port, 443), "account-https")
srv.mux.HandleFunc("/", safeHeaders(accountHandle))
}
if l.AdminHTTP.Enabled {
srv := ensureServe(false, config.Port(l.AdminHTTP.Port, 80), "admin-http")
if !l.AccountHTTP.Enabled {
srv.mux.HandleFunc("/", safeHeaders(adminIndex))
}
srv.mux.HandleFunc("/admin/", safeHeaders(adminHandle))
}
if l.AdminHTTPS.Enabled {
srv := ensureServe(true, config.Port(l.AdminHTTPS.Port, 443), "admin-https")
if !l.AccountHTTP.Enabled {
srv.mux.HandleFunc("/", safeHeaders(adminIndex))
}
srv.mux.HandleFunc("/admin/", safeHeaders(adminHandle))
}
if l.MetricsHTTP.Enabled {
srv := ensureServe(false, config.Port(l.MetricsHTTP.Port, 8010), "metrics-http")
srv.mux.Handle("/metrics", safeHeaders(promhttp.Handler().ServeHTTP))
srv.mux.HandleFunc("/", safeHeaders(func(w http.ResponseWriter, r *http.Request) {
if r.URL.Path != "/" {
http.NotFound(w, r)
return
} else if r.Method != "GET" {
http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
return
}
w.Header().Set("Content-Type", "text/html")
fmt.Fprint(w, `<html><body>see <a href="/metrics">/metrics</a></body></html>`)
}))
}
if l.AutoconfigHTTPS.Enabled {
srv := ensureServe(true, 443, "autoconfig-https")
srv.mux.HandleFunc("/mail/config-v1.1.xml", safeHeaders(autoconfHandle(l)))
srv.mux.HandleFunc("/autodiscover/autodiscover.xml", safeHeaders(autodiscoverHandle(l)))
}
if l.MTASTSHTTPS.Enabled {
srv := ensureServe(true, 443, "mtasts-https")
srv.mux.HandleFunc("/.well-known/mta-sts.txt", safeHeaders(mtastsPolicyHandle))
}
if l.PprofHTTP.Enabled {
// Importing net/http/pprof registers handlers on the default serve mux.
port := config.Port(l.PprofHTTP.Port, 8011)
if _, ok := portServe[port]; ok {
xlog.Fatal("cannot serve pprof on same endpoint as other http services")
}
portServe[port] = serve{[]string{"pprof-http"}, nil, http.DefaultServeMux}
}
// We'll explicitly ensure these TLS certs exist (e.g. are created with ACME)
// immediately after startup. We only do so for our explicitly hostnames, not for
// autoconfig or mta-sts DNS records, they can be requested on demand (perhaps
// never).
ensureHosts := map[dns.Domain]struct{}{}
if l.TLS != nil && l.TLS.ACME != "" {
m := mox.Conf.Static.ACME[l.TLS.ACME].Manager
m.AllowHostname(mox.Conf.Static.HostnameDomain)
ensureHosts[mox.Conf.Static.HostnameDomain] = struct{}{}
if l.HostnameDomain.ASCII != "" {
m.AllowHostname(l.HostnameDomain)
ensureHosts[l.HostnameDomain] = struct{}{}
}
go func() {
// Just in case someone adds quite some domains to their config. We don't want to
// hit any ACME rate limits.
if len(ensureHosts) > 10 {
return
}
time.Sleep(1 * time.Second)
i := 0
for hostname := range ensureHosts {
if i > 0 {
// Sleep just a little. We don't want to hammer our ACME provider, e.g. Let's Encrypt.
time.Sleep(10 * time.Second)
}
i++
hello := &tls.ClientHelloInfo{
ServerName: hostname.ASCII,
// Make us fetch an ECDSA P256 cert.
// We add TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 to get around the ecDSA check in autocert.
CipherSuites: []uint16{tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, tls.TLS_AES_128_GCM_SHA256},
SupportedCurves: []tls.CurveID{tls.CurveP256},
SignatureSchemes: []tls.SignatureScheme{tls.ECDSAWithP256AndSHA256},
SupportedVersions: []uint16{tls.VersionTLS13},
}
xlog.Print("ensuring certificate availability", mlog.Field("hostname", hostname))
if _, err := m.Manager.GetCertificate(hello); err != nil {
xlog.Errorx("requesting automatic certificate", err, mlog.Field("hostname", hostname))
}
}
}()
}
for port, srv := range portServe {
for _, ip := range l.IPs {
listenAndServe(ip, port, srv.tlsConfig, name, srv.kinds, srv.mux)
}
}
}
}
// Only used when the account page is not active on the same listener.
func adminIndex(w http.ResponseWriter, r *http.Request) {
if r.URL.Path != "/" {
http.NotFound(w, r)
return
}
if r.Method != "GET" {
http.Error(w, http.StatusText(http.StatusMethodNotAllowed), http.StatusMethodNotAllowed)
return
}
http.Redirect(w, r, "/admin/", http.StatusSeeOther)
}
func listenAndServe(ip string, port int, tlsConfig *tls.Config, name string, kinds []string, mux *http.ServeMux) {
addr := net.JoinHostPort(ip, fmt.Sprintf("%d", port))
var protocol string
var ln net.Listener
var err error
if tlsConfig == nil {
protocol = "http"
xlog.Print("http listener", mlog.Field("name", name), mlog.Field("kinds", strings.Join(kinds, ",")), mlog.Field("address", addr))
ln, err = net.Listen(mox.Network(ip), addr)
if err != nil {
xlog.Fatalx("http: listen"+mox.LinuxSetcapHint(err), err, mlog.Field("addr", addr))
}
} else {
protocol = "https"
xlog.Print("https listener", mlog.Field("name", name), mlog.Field("kinds", strings.Join(kinds, ",")), mlog.Field("address", addr))
ln, err = tls.Listen(mox.Network(ip), addr, tlsConfig)
if err != nil {
xlog.Fatalx("https: listen"+mox.LinuxSetcapHint(err), err, mlog.Field("addr", addr))
}
}
server := &http.Server{
Handler: mux,
TLSConfig: tlsConfig,
ErrorLog: golog.New(mlog.ErrWriter(xlog.Fields(mlog.Field("pkg", "net/http")), mlog.LevelInfo, protocol+" error"), "", 0),
}
go func() {
err := server.Serve(ln)
xlog.Fatalx(protocol+": serve", err)
}()
}