Simple HTML sanitizer implementation

sanitize/html.go

@@ -0,0 +1,9 @@
+package sanitize
+
+import "github.com/microcosm-cc/bluemonday"
+
+func HTML(html string) (output string, err error) {
+	policy := bluemonday.UGCPolicy()
+	output = policy.Sanitize(html)
+	return
+}

sanitize/html_test.go

@@ -0,0 +1,77 @@
+package sanitize_test
+
+import (
+	"testing"
+
+	"github.com/jhillyerd/inbucket/sanitize"
+)
+
+// TestHTMLPlainStrings test plain text passthrough
+func TestHTMLPlainStrings(t *testing.T) {
+	testStrings := []string{
+		"",
+		"plain string",
+		"one < two",
+	}
+	for _, ts := range testStrings {
+		t.Run(ts, func(t *testing.T) {
+			got, err := sanitize.HTML(ts)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if got != ts {
+				t.Errorf("Got: %q, want: %q", got, ts)
+			}
+		})
+	}
+}
+
+// TestHTMLSimpleFormatting tests basic tags we should allow
+func TestHTMLSimpleFormatting(t *testing.T) {
+	testStrings := []string{
+		"<p>paragraph</p>",
+		"<b>bold</b>",
+		"<i>italic</b>",
+		"<em>emphasis</em>",
+		"<strong>strong</strong>",
+		"<div><span>text</span></div>",
+	}
+	for _, ts := range testStrings {
+		t.Run(ts, func(t *testing.T) {
+			got, err := sanitize.HTML(ts)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if got != ts {
+				t.Errorf("Got: %q, want: %q", got, ts)
+			}
+		})
+	}
+}
+
+// TestHTMLScriptTags tests some strings with JavaScript
+func TestHTMLScriptTags(t *testing.T) {
+	testCases := []struct {
+		input, want string
+	}{
+		{
+			`safe<script>nope</script>`,
+			`safe`,
+		},
+		{
+			`<a onblur="alert(something)" href="http://mysite.com">mysite</a>`,
+			`<a href="http://mysite.com" rel="nofollow">mysite</a>`,
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.input, func(t *testing.T) {
+			got, err := sanitize.HTML(tc.input)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if got != tc.want {
+				t.Errorf("Got: %q, want: %q", got, tc.want)
+			}
+		})
+	}
+}

themes/bootstrap/public/inbucket.css

@@ -51,12 +51,17 @@ body {
   }
 }
 
+#body-tabs > li > a {
+  padding-top: 6px;
+  padding-bottom: 6px;
+}
+
 .message-body {
-  padding: 0 5px;
+  padding: 10px 4px;
 }
 
 .message-attachments {
-  margin-top: 20px;
+  margin-top: 5px;
   padding: 10px 10px 0 0;
 }
 

themes/bootstrap/public/mailbox.js

@@ -157,6 +157,7 @@ function onMessageLoaded(responseText, textStatus, XMLHttpRequest) {
     return;
   }
   onDocumentChange();
+  $('#body-tabs a:first').tab('show')
   var top = $('#message-container').offset().top - navBarOffset;
   $(window).scrollTop(top);
 }

themes/bootstrap/templates/mailbox/_show.html

@@ -24,7 +24,7 @@
             class="btn btn-primary"
             onClick="htmlView('{{.message.ID}}');">
       <span class="glyphicon glyphicon-new-window" aria-hidden="true"></span>
-      HTML
+      Raw HTML
     </button>
   {{end}}
 </div>
@@ -78,7 +78,22 @@
 </div>
 {{end}}
 
-<div class="message-body">{{.body}}</div>
+<nav>
+  <ul id="body-tabs" class="nav nav-tabs" role="tablist">
+    {{if .htmlAvailable}}
+    <li role="presentation">
+      <a href="#body-html" aria-controls="body-html" role="tab" data-toggle="tab">Safe HTML</a>
+    </li>
+    {{end}}
+    <li role="presentation">
+      <a href="#body-text" aria-controls="body-text" role="tab" data-toggle="tab">Plain Text</a>
+    </li>
+  </ul>
+</nav>
+<div class="tab-content">
+  <div role="tabpanel" class="tab-pane message-body" id="body-html">{{.htmlBody}}</div>
+  <div role="tabpanel" class="tab-pane message-body" id="body-text">{{.body}}</div>
+</div>
 
 {{with .attachments}}
 <div class="well message-attachments">

webui/mailbox_controller.go

@@ -10,6 +10,7 @@ import (
 	"github.com/jhillyerd/inbucket/datastore"
 	"github.com/jhillyerd/inbucket/httpd"
 	"github.com/jhillyerd/inbucket/log"
+	"github.com/jhillyerd/inbucket/sanitize"
 	"github.com/jhillyerd/inbucket/stringutil"
 )
 
@@ -118,6 +119,14 @@ func MailboxShow(w http.ResponseWriter, req *http.Request, ctx *httpd.Context) (
 	}
 	body := template.HTML(httpd.TextToHTML(mime.Text))
 	htmlAvailable := mime.HTML != ""
+	var htmlBody template.HTML
+	if htmlAvailable {
+		if str, err := sanitize.HTML(mime.HTML); err == nil {
+			htmlBody = template.HTML(str)
+		} else {
+			log.Warnf("HTML sanitizer failed: %s", err)
+		}
+	}
 	// Render partial template
 	return httpd.RenderPartial("mailbox/_show.html", w, map[string]interface{}{
 		"ctx":           ctx,
@@ -125,6 +134,7 @@ func MailboxShow(w http.ResponseWriter, req *http.Request, ctx *httpd.Context) (
 		"message":       msg,
 		"body":          body,
 		"htmlAvailable": htmlAvailable,
+		"htmlBody":      htmlBody,
 		"mimeErrors":    mime.Errors,
 		"attachments":   mime.Attachments,
 	})