From nobody Tue Apr 7 03:54:17 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EE77EECAAD4 for ; Wed, 31 Aug 2022 08:07:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230154AbiHaIHM (ORCPT ); Wed, 31 Aug 2022 04:07:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46952 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229838AbiHaIHJ (ORCPT ); Wed, 31 Aug 2022 04:07:09 -0400 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 76181F4C; Wed, 31 Aug 2022 01:07:07 -0700 (PDT) Received: from stanislav-HLY-WX9XX.. (unknown [93.175.2.86]) by mail.ispras.ru (Postfix) with ESMTPSA id C490C40755ED; Wed, 31 Aug 2022 08:07:03 +0000 (UTC) From: Stanislav Goriainov To: Miklos Szeredi Cc: Stanislav Goriainov , Vivek Goyal , Amir Goldstein , linux-unionfs@vger.kernel.org, linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org Subject: [PATCH v2] ovl: Add comment on upperredirect reassignment Date: Wed, 31 Aug 2022 11:06:58 +0300 Message-Id: <20220831080658.14878-1-goriainov@ispras.ru> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" If memory for uperredirect was allocated with kstrdup() in upperdir !=3D NULL and d.redirect !=3D NULL path, it may seem that it can be lost when upperredirect is reassigned later, but it's not possible. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: 0a2d0d3f2f291 ("ovl: Check redirect on index as well") Signed-off-by: Stanislav Goriainov --- fs/overlayfs/namei.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c index 69dc577974f8..2a21331e6ccd 100644 --- a/fs/overlayfs/namei.c +++ b/fs/overlayfs/namei.c @@ -1085,6 +1085,11 @@ struct dentry *ovl_lookup(struct inode *dir, struct = dentry *dentry, .mnt =3D ovl_upper_mnt(ofs), }; =20 + /* There is no overwrite of upperredirect here as the first + * assignment of upperredirect happens only if + * upperdentry is non-NULL, while here we are only + * if upperdentry is NULL. + */ upperredirect =3D ovl_get_redirect_xattr(ofs, &upperpath, 0); if (IS_ERR(upperredirect)) { err =3D PTR_ERR(upperredirect); --=20 2.34.1