Prevent an assertion with invalid Unicode sequences

Invalid Unicode sequences, such as 0x2665 0xfe0e 0xfe0f, can trick the Emoji iter code into returning an empty segment, which then triggers an assertion in the itemizer. Prevent this by ensuring that we make progress. This issue was reported by Jeffrey M.
GNOME · Aug 18, 2018 · 71aaeaf · 71aaeaf
1 parent ccfd3b4
commit 71aaeaf
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/pango/pango-emoji.c b/pango/pango-emoji.c
@@ -253,6 +253,12 @@ _pango_emoji_iter_next (PangoEmojiIter *iter)
     if (iter->is_emoji == PANGO_EMOJI_TYPE_IS_EMOJI (current_emoji_type))
     {
       iter->is_emoji = !PANGO_EMOJI_TYPE_IS_EMOJI (current_emoji_type);
+
+      /* Make sure we make progress.  Weird sequences, like a VC15 followed
+       * by VC16, can trick us into stalling otherwise. */
+      if (iter->start == iter->end)
+        iter->end = g_utf8_next_char (iter->end);
+
       return TRUE;
     }
   }