[pango] bidi: Be safer against bad input

[Matthias Clasen <matthiasc src gnome org>]

commit 490f8979a260c16b1df055eab386345da18a2d54
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jul 10 20:26:23 2019 -0400

    bidi: Be safer against bad input
    
    Don't run off the end of an array that we
    allocated to certain length.
    
    Closes: https://gitlab.gnome.org/GNOME/pango/issues/342

 pango/pango-bidi-type.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/pango/pango-bidi-type.c b/pango/pango-bidi-type.c
index 3e46b66c..5c02dbbb 100644
--- a/pango/pango-bidi-type.c
+++ b/pango/pango-bidi-type.c
@@ -181,8 +181,11 @@ pango_log2vis_get_embedding_levels (const gchar    *text,
   for (i = 0, p = text; p < text + length; p = g_utf8_next_char(p), i++)
     {
       gunichar ch = g_utf8_get_char (p);
-      FriBidiCharType char_type;
-      char_type = fribidi_get_bidi_type (ch);
+      FriBidiCharType char_type = fribidi_get_bidi_type (ch);
+
+      if (i == n_chars)
+        break;
+
       bidi_types[i] = char_type;
       ored_types |= char_type;
       if (FRIBIDI_IS_STRONG (char_type))