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.
This commit is contained in:
Mechiel Lukkien
2023-02-13 13:53:47 +01:00
parent 2601766c2f
commit ad51ffc365
13 changed files with 154 additions and 64 deletions

View File

@ -108,21 +108,46 @@ func init() {
// check whether authentication from the config (passwordfile with bcrypt hash)
// matches the authorization header "authHdr". we don't care about any username.
func checkAdminAuth(ctx context.Context, passwordfile, authHdr string) bool {
// on (auth) failure, a http response is sent and false returned.
func checkAdminAuth(ctx context.Context, passwordfile string, w http.ResponseWriter, r *http.Request) bool {
log := xlog.WithContext(ctx)
respondAuthFail := func() bool {
// note: browsers don't display the realm to prevent users getting confused by malicious realm messages.
w.Header().Set("WWW-Authenticate", `Basic realm="mox admin - login with empty username and admin password"`)
http.Error(w, "http 401 - unauthorized - mox admin - login with empty username and admin password", http.StatusUnauthorized)
return false
}
authResult := "error"
start := time.Now()
var addr *net.TCPAddr
defer func() {
metrics.AuthenticationInc("httpadmin", "httpbasic", authResult)
if authResult == "ok" && addr != nil {
mox.LimiterFailedAuth.Reset(addr.IP, start)
}
}()
if !strings.HasPrefix(authHdr, "Basic ") || passwordfile == "" {
var err error
addr, err = net.ResolveTCPAddr("tcp", r.RemoteAddr)
if err != nil {
log.Errorx("parsing remote address", err, mlog.Field("addr", r.RemoteAddr))
}
if addr != nil && !mox.LimiterFailedAuth.Add(addr.IP, start, 1) {
metrics.AuthenticationRatelimitedInc("httpadmin")
http.Error(w, "http 429 - too many auth attempts", http.StatusTooManyRequests)
return false
}
authHdr := r.Header.Get("Authorization")
if !strings.HasPrefix(authHdr, "Basic ") || passwordfile == "" {
return respondAuthFail()
}
buf, err := os.ReadFile(passwordfile)
if err != nil {
log.Errorx("reading admin password file", err, mlog.Field("path", passwordfile))
return false
return respondAuthFail()
}
passwordhash := strings.TrimSpace(string(buf))
authCache.Lock()
@ -133,15 +158,15 @@ func checkAdminAuth(ctx context.Context, passwordfile, authHdr string) bool {
}
auth, err := base64.StdEncoding.DecodeString(strings.TrimPrefix(authHdr, "Basic "))
if err != nil {
return false
return respondAuthFail()
}
t := strings.SplitN(string(auth), ":", 2)
if len(t) != 2 || len(t[1]) < 8 {
return false
return respondAuthFail()
}
if err := bcrypt.CompareHashAndPassword([]byte(passwordhash), []byte(t[1])); err != nil {
authResult = "badcreds"
return false
return respondAuthFail()
}
authCache.lastSuccessHash = passwordhash
authCache.lastSuccessAuth = authHdr
@ -151,10 +176,8 @@ func checkAdminAuth(ctx context.Context, passwordfile, authHdr string) bool {
func adminHandle(w http.ResponseWriter, r *http.Request) {
ctx := context.WithValue(r.Context(), mlog.CidKey, mox.Cid())
if !checkAdminAuth(ctx, mox.ConfigDirPath(mox.Conf.Static.AdminPasswordFile), r.Header.Get("Authorization")) {
w.Header().Set("WWW-Authenticate", `Basic realm="mox admin - login with empty username and admin password"`)
w.WriteHeader(http.StatusUnauthorized)
fmt.Fprintln(w, "http 401 - unauthorized - mox admin - login with empty username and admin password")
if !checkAdminAuth(ctx, mox.ConfigDirPath(mox.Conf.Static.AdminPasswordFile), w, r) {
// Response already sent.
return
}