BGO#650286: Ensure valid UTF-8 from ATK

When we receive strings from atk, we should ensure that they are valid UTF-8
before sending them over D-Bus, since bad UTF-8 will cause dbus-daemon to
kill the connection.

3 files changed, 32 insertions, 10 deletions

diff --git a/atk-adaptor/adaptors/text-adaptor.c b/atk-adaptor/adaptors/text-adaptor.c
index 0fa35f9..7a810b2 100644
--- a/atk-adaptor/adaptors/text-adaptor.c
+++ b/atk-adaptor/adaptors/text-adaptor.c
@@ -47,6 +47,20 @@ impl_get_CaretOffset (DBusMessageIter * iter, void *user_data)
   return droute_return_v_int32 (iter, atk_text_get_caret_offset (text));
 }
 
+static gchar *
+validate_allocated_string (gchar *str)
+{
+  if (!str)
+    return g_strdup ("");
+  if (!g_utf8_validate (str, -1, NULL))
+    {
+      g_warning ("atk-bridge: received bad UTF-8 string from a get_text function");
+      g_free (str);
+      return g_strdup ("");
+    }
+  return str;
+}
+
 static DBusMessage *
 impl_GetText (DBusConnection * bus, DBusMessage * message, void *user_data)
 {
@@ -66,8 +80,7 @@ impl_GetText (DBusConnection * bus, DBusMessage * message, void *user_data)
       return droute_invalid_arguments_error (message);
     }
   txt = atk_text_get_text (text, startOffset, endOffset);
-  if (!txt)
-    txt = g_strdup ("");
+  txt = validate_allocated_string (txt);
   reply = dbus_message_new_method_return (message);
   if (reply)
     {
@@ -133,8 +146,7 @@ impl_GetTextBeforeOffset (DBusConnection * bus, DBusMessage * message,
                                      &intstart_offset, &intend_offset);
   startOffset = intstart_offset;
   endOffset = intend_offset;
-  if (!txt)
-    txt = g_strdup ("");
+  txt = validate_allocated_string (txt);
   reply = dbus_message_new_method_return (message);
   if (reply)
     {
@@ -173,8 +185,7 @@ impl_GetTextAtOffset (DBusConnection * bus, DBusMessage * message,
                                  &intstart_offset, &intend_offset);
   startOffset = intstart_offset;
   endOffset = intend_offset;
-  if (!txt)
-    txt = g_strdup ("");
+  txt = validate_allocated_string (txt);
   reply = dbus_message_new_method_return (message);
   if (reply)
     {
@@ -214,8 +225,7 @@ impl_GetTextAfterOffset (DBusConnection * bus, DBusMessage * message,
                                     &intstart_offset, &intend_offset);
   startOffset = intstart_offset;
   endOffset = intend_offset;
-  if (!txt)
-    txt = g_strdup ("");
+  txt = validate_allocated_string (txt);
   reply = dbus_message_new_method_return (message);
   if (reply)
     {
diff --git a/atk-adaptor/event.c b/atk-adaptor/event.c
index d489a13..8d04246 100644
--- a/atk-adaptor/event.c
+++ b/atk-adaptor/event.c
@@ -228,7 +228,7 @@ convert_signal_name (const gchar * s)
 }
 
 static const void *
-replace_null (const gint type,
+validate_for_dbus (const gint type,
               const void *val)
 {
   switch (type)
@@ -237,6 +237,11 @@ replace_null (const gint type,
       case DBUS_TYPE_OBJECT_PATH:
 	   if (!val)
 	      return "";
+	   else if (!g_utf8_validate (val, -1, NULL))
+             {
+	       g_warning ("atk-bridge: Received bad UTF-8 string when emitting event");
+	       return "";
+               }
 	   else
 	      return val;
       default:
@@ -253,7 +258,7 @@ append_basic (DBusMessageIter *iter,
 
   dbus_message_iter_open_container(iter, DBUS_TYPE_VARIANT, type, &sub);
 
-    val = replace_null ((int) *type, val);
+    val = validate_for_dbus ((int) *type, val);
     dbus_message_iter_append_basic(&sub, (int) *type, &val);
 
   dbus_message_iter_close_container(iter, &sub);
diff --git a/droute/droute-variant.c b/droute/droute-variant.c
index d4b5ca6..bd5ef36 100644
--- a/droute/droute-variant.c
+++ b/droute/droute-variant.c
@@ -22,6 +22,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include "glib.h"
 
 #include "droute-variant.h"
 
@@ -64,6 +65,12 @@ droute_return_v_string (DBusMessageIter *iter, const char *val)
 
     if (!val)
       val = "";
+    if (!g_utf8_validate (val, -1, NULL))
+      {
+        g_warning ("droute: Received bad UTF-8 string");
+        val = "";
+      }
+
     if (!dbus_message_iter_open_container
         (iter, DBUS_TYPE_VARIANT, DBUS_TYPE_STRING_AS_STRING, &sub))
       {