From nobody Tue Jun 23 07:10:27 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 AA05AC433F5 for ; Wed, 9 Mar 2022 12:19:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232520AbiCIMUJ (ORCPT ); Wed, 9 Mar 2022 07:20:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229514AbiCIMUH (ORCPT ); Wed, 9 Mar 2022 07:20:07 -0500 Received: from mail-m972.mail.163.com (mail-m972.mail.163.com [123.126.97.2]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B617312F404; Wed, 9 Mar 2022 04:19:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=79aUx 1c7CPT8LgoaiDSdBrkYa0kTdsJauFmLg37A0L0=; b=VoPwc4VTZ8G5D9wgi9/jX JBS9L4MPrTsSb+8aAfvIYuOaRWQY3t7wSBgCx2n7Yo3BYEeUCzPdQ6KRn2iddndf tJBmSaInX5oCUmZ/JC92qIahUdUPMrMvymtXuH8Y7g7av/4+YVUJtGNvMLptDPEC N8AcFML5UuZnbc5fMsr6Mg= Received: from localhost.localdomain (unknown [218.106.182.227]) by smtp2 (Coremail) with SMTP id GtxpCgDXZW4TmyhiJ7pvBA--.12980S4; Wed, 09 Mar 2022 20:18:35 +0800 (CST) From: Jianglei Nie To: davem@davemloft.net, kuba@kernel.org, caihuoqing@baidu.com, andrew@lunn.ch Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jianglei Nie Subject: [PATCH v2] net: arc_emac: Fix use after free in arc_mdio_probe() Date: Wed, 9 Mar 2022 20:18:24 +0800 Message-Id: <20220309121824.36529-1-niejianglei2021@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: GtxpCgDXZW4TmyhiJ7pvBA--.12980S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7Kr4fXFWUKFW7KFyrCFyrCrg_yoW8Xw4xpa yUu3srA3s2qw1UKF4kAay0v343tayrJryj9FyIvws0qw15Zr1fGrW7KFWq9w1UKF4qkF1a qa1xZFyrAFZ8JwUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zR4E_iUUUUU= X-Originating-IP: [218.106.182.227] X-CM-SenderInfo: xqlhyxxdqjzvrlsqjii6rwjhhfrp/1tbiDxu+jFUMb4IN1gAAsJ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" If bus->state is equal to MDIOBUS_ALLOCATED, mdiobus_free(bus) will free the "bus". But bus->name is still used in the next line, which will lead to a use after free. We can fix it by putting the name in a local variable and make the bus->name point to the rodata section "name",then use the name in the error message without referring to bus to avoid the uaf. Signed-off-by: Jianglei Nie --- drivers/net/ethernet/arc/emac_mdio.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/arc/emac_mdio.c b/drivers/net/ethernet/ar= c/emac_mdio.c index 9acf589b1178..87f40c2ba904 100644 --- a/drivers/net/ethernet/arc/emac_mdio.c +++ b/drivers/net/ethernet/arc/emac_mdio.c @@ -132,6 +132,7 @@ int arc_mdio_probe(struct arc_emac_priv *priv) { struct arc_emac_mdio_bus_data *data =3D &priv->bus_data; struct device_node *np =3D priv->dev->of_node; + const char *name =3D "Synopsys MII Bus"; struct mii_bus *bus; int error; =20 @@ -142,7 +143,7 @@ int arc_mdio_probe(struct arc_emac_priv *priv) priv->bus =3D bus; bus->priv =3D priv; bus->parent =3D priv->dev; - bus->name =3D "Synopsys MII Bus"; + bus->name =3D name; bus->read =3D &arc_mdio_read; bus->write =3D &arc_mdio_write; bus->reset =3D &arc_mdio_reset; @@ -167,7 +168,7 @@ int arc_mdio_probe(struct arc_emac_priv *priv) if (error) { mdiobus_free(bus); return dev_err_probe(priv->dev, error, - "cannot register MDIO bus %s\n", bus->name); + "cannot register MDIO bus %s\n", name); } =20 return 0; --=20 2.25.1