From 2275b773ebfacb94f6a9c81d6a8b9d54771a68e8 Mon Sep 17 00:00:00 2001 From: "Miss Islington (bot)" <31488909+miss-islington@users.noreply.github.com> Date: Wed, 15 Aug 2018 02:51:12 -0400 Subject: closes bpo-34400: Fix undefined behavior in parsetok(). (GH-4439) Avoid undefined pointer arithmetic with NULL. (cherry picked from commit 7c4ab2afb17b99eb3f61f9c73cbd548b5e0ad2c0) Co-authored-by: Zackery Spytz --- Parser/parsetok.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Parser') diff --git a/Parser/parsetok.c b/Parser/parsetok.c index 00d741d221..b9c9fe8fa8 100644 --- a/Parser/parsetok.c +++ b/Parser/parsetok.c @@ -225,7 +225,7 @@ parsetok(struct tok_state *tok, grammar *g, int start, perrdetail *err_ret, } else started = 1; - len = b - a; /* XXX this may compute NULL - NULL */ + len = (a != NULL && b != NULL) ? b - a : 0; str = (char *) PyObject_MALLOC(len + 1); if (str == NULL) { err_ret->error = E_NOMEM; -- cgit v1.2.1