[gnome-terminal] app: Only allow valid charsets

[Christian Persch <chpe src gnome org>]

commit b0bdd4740f82daa6c2bb020738a857b8e8d2a6dd
Author: Christian Persch <chpe gnome org>
Date:   Tue May 20 16:04:15 2014 +0200

    app: Only allow valid charsets
    
    Charsets must be [-_A-Za-z0-9] only.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=730390

 src/terminal-app.c |   23 +++++++++++++++++++++--
 1 files changed, 21 insertions(+), 2 deletions(-)
---
diff --git a/src/terminal-app.c b/src/terminal-app.c
index 33f6e6f..64c7dd3 100644
--- a/src/terminal-app.c
+++ b/src/terminal-app.c
@@ -625,6 +625,25 @@ terminal_app_get_encodings (TerminalApp *app)
   return app->encodings;
 }
 
+static const char *
+charset_validated (const char *charset)
+{
+  gsize i;
+
+  if (charset == NULL)
+    goto out;
+
+  for (i = 0; charset[i] != '\0'; i++) {
+    char c = charset[i];
+    if (!(g_ascii_isalnum(c) || c == '_' || c == '-'))
+      goto out;
+  }
+
+  return charset;
+ out:
+  return "UTF-8";
+}
+
 /**
  * terminal_app_ensure_encoding:
  * @app:
@@ -635,7 +654,7 @@ terminal_app_get_encodings (TerminalApp *app)
  * @charset is not a known charset, returns a #TerminalEncoding for a
  * custom charset.
  *
- * Returns: (transfer none): a #TerminalEncoding
+ * Returns: (transfer none): a #TerminalEncoding, or %NULL
  */
 TerminalEncoding *
 terminal_app_ensure_encoding (TerminalApp *app,
@@ -643,7 +662,7 @@ terminal_app_ensure_encoding (TerminalApp *app,
 {
   TerminalEncoding *encoding;
 
-  encoding = g_hash_table_lookup (app->encodings, charset ? charset : "UTF-8");
+  encoding = g_hash_table_lookup (app->encodings, charset_validated (charset));
   if (encoding == NULL)
     {
       encoding = terminal_encoding_new (charset,