added tabs to terminal, split single .go to separate files

internals/auth.go

@@ -0,0 +1,56 @@
+package internals
+
+import (
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"net/http"
+	"strings"
+	"time"
+)
+
+func checkCreds(username, password string) bool {
+	if username != appCreds.Username {
+		return false
+	}
+	got := hashPassword(password, appCreds.Salt)
+	return hmac.Equal([]byte(got), []byte(appCreds.Hash))
+}
+
+func initAuthSecret() {
+	authSecret = make([]byte, 32)
+	rand.Read(authSecret)
+}
+
+func makeAuthToken() string {
+	ts := fmt.Sprintf("%d", time.Now().Unix())
+	mac := hmac.New(sha256.New, authSecret)
+	mac.Write([]byte(ts))
+	return ts + "." + hex.EncodeToString(mac.Sum(nil))
+}
+
+func validAuthToken(token string) bool {
+	dot := strings.LastIndex(token, ".")
+	if dot < 0 {
+		return false
+	}
+	ts, sig := token[:dot], token[dot+1:]
+	mac := hmac.New(sha256.New, authSecret)
+	mac.Write([]byte(ts))
+	if !hmac.Equal([]byte(sig), []byte(hex.EncodeToString(mac.Sum(nil)))) {
+		return false
+	}
+	var t int64
+	fmt.Sscanf(ts, "%d", &t)
+	return time.Since(time.Unix(t, 0)) < authTokenTTL
+}
+
+func isAuthed(r *http.Request) bool {
+	if nopwMode {
+		return true
+	}
+	c, err := r.Cookie(authCookieName)
+	return err == nil && validAuthToken(c.Value)
+}