[epiphany/gnome-40] pdf-handler: properly encode filename before inserting to HTML

[Michael Catanzaro <mcatanzaro src gnome org>]

commit da389b66130793ed4899a256b21048986007c6b3
Author: Michael Catanzaro <mcatanzaro redhat com>
Date:   Tue Dec 14 16:46:07 2021 -0600

    pdf-handler: properly encode filename before inserting to HTML
    
    The file's name is suggested by the server, and could be malicious. We
    don't want it to be able to escape the HTML attribute context.
    
    The file data should already be safe because it is base-64 encoded. Here
    I'm just adjusting the code style to match what I've done for the
    filename.
    
    Part-of: <https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/1045>

 embed/ephy-pdf-handler.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)
---
diff --git a/embed/ephy-pdf-handler.c b/embed/ephy-pdf-handler.c
index da10b7e02..bcc226c5f 100644
--- a/embed/ephy-pdf-handler.c
+++ b/embed/ephy-pdf-handler.c
@@ -23,6 +23,7 @@
 
 #include "ephy-embed-container.h"
 #include "ephy-embed-shell.h"
+#include "ephy-output-encoding.h"
 #include "ephy-web-view.h"
 
 #include <gio/gio.h>
@@ -124,8 +125,9 @@ pdf_file_loaded (GObject      *source,
   g_autoptr (GBytes) html_file = NULL;
   g_autoptr (GError) error = NULL;
   g_autoptr (GString) html = NULL;
-  g_autofree gchar *b64 = NULL;
   g_autofree char *file_data = NULL;
+  g_autofree char *encoded_file_data = NULL;
+  g_autofree char *encoded_filename = NULL;
   gsize len = 0;
 
   if (!g_file_load_contents_finish (G_FILE (source), res, &file_data, &len, NULL, &error)) {
@@ -134,13 +136,13 @@ pdf_file_loaded (GObject      *source,
     return;
   }
 
-  html_file = g_resources_lookup_data ("/org/gnome/epiphany/pdfjs/web/viewer.html", 0, NULL);
-
-  b64 = g_base64_encode ((const guchar *)file_data, len);
   g_file_delete_async (G_FILE (source), G_PRIORITY_DEFAULT, NULL, pdf_file_deleted, NULL);
 
-  html = g_string_new ("");
-  g_string_printf (html, g_bytes_get_data (html_file, NULL), b64, self->file_name ? self->file_name : "");
+  html = g_string_new (NULL);
+  html_file = g_resources_lookup_data ("/org/gnome/epiphany/pdfjs/web/viewer.html", 0, NULL);
+  encoded_file_data = g_base64_encode ((const guchar *)file_data, len);
+  encoded_filename = self->file_name ? ephy_encode_for_html_attribute (self->file_name) : g_strdup ("");
+  g_string_printf (html, g_bytes_get_data (html_file, NULL), encoded_file_data, encoded_filename);
 
   finish_uri_scheme_request (self, g_strdup (html->str), NULL);
 }