From nobody Tue Jun 23 09:12:56 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 90CDEC433EF for ; Tue, 8 Mar 2022 11:10:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346343AbiCHLLp (ORCPT ); Tue, 8 Mar 2022 06:11:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346321AbiCHLLe (ORCPT ); Tue, 8 Mar 2022 06:11:34 -0500 Received: from mail-m971.mail.163.com (mail-m971.mail.163.com [123.126.97.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2509C45060; Tue, 8 Mar 2022 03:10:36 -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=FR44s W/93AnOynT8YortolDQmhxdwDJugx6homStZRM=; b=OC0XVlzJrZvmckrxWWt6v VMkhI8LQVYi2rUmTr1nw5HXOjZ7Ag3bjbYdrjrS4mh1r6hSknOB5P6zTE5BF9vzI 8YS9rCFwAXqRvENwZrdt+s7jK3Lsb5wHr4RaocN2bV3/QJxqA73WzuJ0WFqNIIrQ brqB8Q5sMZy7emoDnvXjvY= Received: from localhost.localdomain (unknown [218.106.182.227]) by smtp1 (Coremail) with SMTP id GdxpCgAHV3CPOSdiEZZBCg--.8441S4; Tue, 08 Mar 2022 19:10:17 +0800 (CST) From: Jianglei Nie To: davem@davemloft.net, kuba@kernel.org, caihuoqing@baidu.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jianglei Nie Subject: [PATCH] net: arc_emac: Fix use after free in arc_mdio_probe() Date: Tue, 8 Mar 2022 19:10:05 +0800 Message-Id: <20220308111005.4953-1-niejianglei2021@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: GdxpCgAHV3CPOSdiEZZBCg--.8441S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7Kr43CrWxXrWrKw4UZry5urg_yoW8XrW8pa yDu3srC3s2vw4jgw4kAay8Z343tayrJry09FyIvw4Yq3Wavr1fCrW7KFWDuw1UKFsYkF1a yan7Za4rAF98Jw7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zR4E_iUUUUU= X-Originating-IP: [218.106.182.227] X-CM-SenderInfo: xqlhyxxdqjzvrlsqjii6rwjhhfrp/1tbiPhm9jFxBqhITpQAAsF 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 bus->name in a local variable and 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..33fd63d227ef 100644 --- a/drivers/net/ethernet/arc/emac_mdio.c +++ b/drivers/net/ethernet/arc/emac_mdio.c @@ -134,6 +134,7 @@ int arc_mdio_probe(struct arc_emac_priv *priv) struct device_node *np =3D priv->dev->of_node; struct mii_bus *bus; int error; + const char *name =3D "Synopsys MII Bus"; =20 bus =3D mdiobus_alloc(); if (!bus) @@ -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