Avoid possible integer overflows computing indexes in OT layout

harfbuzz · Nov 9, 2024 · 61ee39e · 61ee39e
1 parent 7386be4
commit 61ee39e
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/src/hb/ot_layout_gsubgpos.rs b/src/hb/ot_layout_gsubgpos.rs
@@ -867,7 +867,9 @@ fn apply_lookup(
             match_positions[j] = (match_positions[j] as isize + delta) as _;
         }
 
-        backtrack_len + match_end - ctx.buffer.idx
+        backtrack_len
+            .saturating_add(match_end)
+            .saturating_sub(ctx.buffer.idx)
     };
 
     for record in lookups {