bpo-34400: Fix more undefined behavior in parsetok.c (GH-8833)

python · Aug 21, 2018 · 3e26e42 · 3e26e42
1 parent cdbf50c
commit 3e26e42
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/Parser/parsetok.c b/Parser/parsetok.c
@@ -252,11 +252,13 @@ parsetok(struct tok_state *tok, grammar *g, int start, perrdetail *err_ret,
             }
         }
 #endif
-        if (a >= tok->line_start)
+        if (a != NULL && a >= tok->line_start) {
             col_offset = Py_SAFE_DOWNCAST(a - tok->line_start,
                                           intptr_t, int);
-        else
+        }
+        else {
             col_offset = -1;
+        }
 
         if ((err_ret->error =
              PyParser_AddToken(ps, (int)type, str,