Fix some security issues

* The CSS styles were leaking information about tunnels, even for
  things like the login page, which can be sent to anyone.
* Tokens could be created for any user by any user.

api.go

@@ -160,6 +160,28 @@ func (a *Api) DeleteTunnel(tokenData TokenData, params url.Values) error {
 	return nil
 }
 
+func (a *Api) CreateToken(tokenData TokenData, params url.Values) (string, error) {
+
+	owner := params.Get("owner")
+	if owner == "" {
+		return "", errors.New("Invalid owner paramater")
+	}
+
+	if tokenData.Owner != owner {
+		user, _ := a.db.GetUser(tokenData.Owner)
+		if !user.IsAdmin {
+			return "", errors.New("Unauthorized")
+		}
+	}
+
+	token, err := a.db.AddToken(owner)
+	if err != nil {
+		return "", errors.New("Failed to create token")
+	}
+
+	return token, nil
+}
+
 func (a *Api) handleTunnels(w http.ResponseWriter, r *http.Request) {
 
 	token, err := extractToken("access_token", r)

todo.md

@@ -1,7 +1,7 @@
 # 31 Oct 2020 Launch List
 
 - [ ] I think it's possible to create tokens for arbitrary user, even if you're not that user.
-- [ ] Responses to unauthorized requests are leaking information about the current tunnels through the genereated CSS.
+- [ ] QR codes for admin are broken
 - [ ] General security review.
 - [ ] Invalid database is wiping out tunnels
 - [ ] Improve SSH key download UI.
@@ -11,6 +11,8 @@
 - [ ] Demo video
 - [ ] Demo auto email signup
 - [ ] Post on /r/selfhosted
+- [x] Head can be rendered before h.headHtml is ever set, ie if login page is visited before any other page
+- [x] Responses to unauthorized requests are leaking information about the current tunnels through the genereated CSS.
 
 
 # Eventually 

ui_handler.go

@@ -72,10 +72,6 @@ type HeadData struct {
 	Styles template.CSS
 }
 
-type StylesData struct {
-	Tunnels map[string]Tunnel
-}
-
 type MenuData struct {
 	IsAdmin bool
 }
@@ -107,6 +103,39 @@ func (h *WebUiHandler) handleWebUiRequest(w http.ResponseWriter, r *http.Request
 
 	homePath := "/#/tunnel"
 
+	// Note: h.box and h.headHtml need to be ready before pretty much
+	// everything else, including sendLoginPage
+
+	box, err := rice.FindBox("webui")
+	if err != nil {
+		w.WriteHeader(500)
+		io.WriteString(w, "Error opening webui")
+		return
+	}
+	h.box = box
+
+	stylesText, err := box.String("styles.css")
+	if err != nil {
+		w.WriteHeader(500)
+		io.WriteString(w, "Error reading styles.css")
+		return
+	}
+	headTmplStr, err := box.String("head.tmpl")
+	if err != nil {
+		w.WriteHeader(500)
+		io.WriteString(w, "Error reading head.tmpl")
+		return
+	}
+	headTmpl, err := template.New("head").Parse(headTmplStr)
+	if err != nil {
+		w.WriteHeader(500)
+		io.WriteString(w, "Error compiling head.tmpl")
+		return
+	}
+	var headBuilder strings.Builder
+	headTmpl.Execute(&headBuilder, HeadData{Styles: template.CSS(stylesText)})
+	h.headHtml = template.HTML(headBuilder.String())
+
 	token, err := extractToken("access_token", r)
 	if err != nil {
 		h.sendLoginPage(w, r, 401)
@@ -121,29 +150,6 @@ func (h *WebUiHandler) handleWebUiRequest(w http.ResponseWriter, r *http.Request
 
 	user, _ := h.db.GetUser(tokenData.Owner)
 
-	box, err := rice.FindBox("webui")
-	if err != nil {
-		w.WriteHeader(500)
-		io.WriteString(w, "Error opening webui")
-		return
-	}
-
-	h.box = box
-
-	stylesText, err := box.String("styles.css")
-	if err != nil {
-		w.WriteHeader(500)
-		io.WriteString(w, "Error reading styles.css")
-		return
-	}
-
-	stylesTmpl, err := template.New("styles").Parse(stylesText)
-	if err != nil {
-		w.WriteHeader(500)
-		h.alertDialog(w, r, err.Error(), homePath)
-		return
-	}
-
 	tunnels := h.api.GetTunnels(tokenData)
 
 	for domain, tun := range tunnels {
@@ -152,28 +158,6 @@ func (h *WebUiHandler) handleWebUiRequest(w http.ResponseWriter, r *http.Request
 		tunnels[domain] = tun
 	}
 
-	var stylesBuilder strings.Builder
-	stylesTmpl.Execute(&stylesBuilder, StylesData{Tunnels: tunnels})
-
-	headTmplStr, err := box.String("head.tmpl")
-	if err != nil {
-		w.WriteHeader(500)
-		io.WriteString(w, "Error reading head.tmpl")
-		return
-	}
-
-	headTmpl, err := template.New("head").Parse(headTmplStr)
-	if err != nil {
-		w.WriteHeader(500)
-		io.WriteString(w, "Error compiling head.tmpl")
-		return
-	}
-
-	var headBuilder strings.Builder
-	headTmpl.Execute(&headBuilder, HeadData{Styles: template.CSS(stylesBuilder.String())})
-
-	h.headHtml = template.HTML(headBuilder.String())
-
 	switch r.URL.Path {
 	case "/login":
 		h.handleLogin(w, r)
@@ -396,26 +380,10 @@ func (h *WebUiHandler) handleTokens(w http.ResponseWriter, r *http.Request, user
 
 	r.ParseForm()
 
-	if len(r.Form["owner"]) != 1 {
+	_, err := h.api.CreateToken(tokenData, r.Form)
-		w.WriteHeader(400)
-		h.alertDialog(w, r, "Invalid owner parameter", "/#/tokens")
-		return
-	}
-	owner := r.Form["owner"][0]
-
-	users := h.db.GetUsers()
-
-	_, exists := users[owner]
-	if !exists {
-		w.WriteHeader(400)
-		h.alertDialog(w, r, "Owner doesn't exist", "/#/tokens")
-		return
-	}
-
-	_, err := h.db.AddToken(owner)
 	if err != nil {
 		w.WriteHeader(500)
-		h.alertDialog(w, r, "Failed creating token", "/#/tokens")
+		h.alertDialog(w, r, err.Error(), "/#/tokens")
 		return
 	}
 
@@ -578,7 +546,7 @@ func (h *WebUiHandler) sendLoginPage(w http.ResponseWriter, r *http.Request, cod
 		return
 	}
 
-	loginTemplate, err := template.New("test").Parse(loginTemplateStr)
+	loginTemplate, err := template.New("login").Parse(loginTemplateStr)
 	if err != nil {
 		w.WriteHeader(500)
 		io.WriteString(w, "Error compiling login.tmpl")

webui/index.tmpl

@@ -2,6 +2,29 @@
 <html>
   <head>
     {{.Head}}
+
+    <style>
+      {{range $domain, $tunnel:= .Tunnels}}
+      #toggle-tunnel-delete-dialog-{{$tunnel.CssId}} {
+        display: none;
+      }
+      #toggle-tunnel-delete-dialog-{{$tunnel.CssId}}:checked + .dialog {
+        display: block;
+      }
+      
+      #toggle-tunnel-hide-deleted-{{$tunnel.CssId}}:checked + .list-item {
+        /* This is a trick to make the delete request after the delete button is
+         * clicked. The background will never actually be displayed, because it's
+         * moved offscreen. */
+        position: absolute;
+        left: -999em;
+        background: url("/delete-tunnel?domain={{$domain}}");
+      }
+      #toggle-tunnel-hide-deleted-{{$tunnel.CssId}}:checked ~ .dialog {
+        display: none;
+      }
+      {{end}}
+    </style>
   </head>
 
   <body>

webui/styles.css

@@ -229,27 +229,6 @@ main *:target {
   z-index: 1010;
 }
 
-{{range $domain, $tunnel:= .Tunnels}}
-#toggle-tunnel-delete-dialog-{{$tunnel.CssId}} {
-  display: none;
-}
-#toggle-tunnel-delete-dialog-{{$tunnel.CssId}}:checked + .dialog {
-  display: block;
-}
-
-#toggle-tunnel-hide-deleted-{{$tunnel.CssId}}:checked + .list-item {
-  /* This is a trick to make the delete request after the delete button is
-   * clicked. The background will never actually be displayed, because it's
-   * moved offscreen. */
-  position: absolute;
-  left: -999em;
-  background: url("/delete-tunnel?domain={{$domain}}");
-}
-#toggle-tunnel-hide-deleted-{{$tunnel.CssId}}:checked ~ .dialog {
-  display: none;
-}
-{{end}}
-
 @media (min-width: 640px) {
 
   main {