kc3-lang/freetype

diff --git a/ChangeLog b/ChangeLog
index 3cf0002..da002ab 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
 2016-08-16  Werner Lemberg  <wl@gnu.org>
 
+	[lzw] Avoid buffer overrun.
+
+	Reported as
+
+	  https://bugzilla.mozilla.org/show_bug.cgi?id=1273283
+
+	* src/lzw/ftzopen.c (ft_lzwstate_refill): Ensure `buf_size' doesn't
+	underflow.
+
+2016-08-16  Werner Lemberg  <wl@gnu.org>
+
 	[truetype] Fix compiler warning.
 
 	* src/truetype/ttgload.c (load_truetype_glyph): Add cast.
diff --git a/src/lzw/ftzopen.c b/src/lzw/ftzopen.c
index e17b3c5..32839cc 100644
--- a/src/lzw/ftzopen.c
+++ b/src/lzw/ftzopen.c
@@ -42,7 +42,12 @@
     state->buf_total += count;
     state->in_eof     = FT_BOOL( count < state->num_bits );
     state->buf_offset = 0;
-    state->buf_size   = ( state->buf_size << 3 ) - ( state->num_bits - 1 );
+
+    state->buf_size <<= 3;
+    if ( state->buf_size > state->num_bits )
+      state->buf_size -= state->num_bits - 1;
+    else
+      return -1; /* not enough data */
 
     if ( count == 0 )  /* end of file */
       return -1;