From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
To:     Linus Walleij <linus.walleij@linaro.org>,
        =?UTF-8?q?Alvin=20=C5=A0ipraga?= <alsi@bang-olufsen.dk>,
        Andrew Lunn <andrew@lunn.ch>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Vladimir Oltean <olteanv@gmail.com>,
        Luiz Angelo Daros de Luca <luizluca@gmail.com>,
        "David S. Miller" <davem@davemloft.net>
Cc:     kernel@pengutronix.de, Ahmad Fatoum <a.fatoum@pengutronix.de>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH net 1/2] net: dsa: realtek: fix out-of-bounds access
Date:   Wed, 15 Mar 2023 14:09:15 +0100
Message-Id: <20230315130917.3633491-1-a.fatoum@pengutronix.de>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The probe function sets priv->chip_data to (void *)priv + sizeof(*priv)
with the expectation that priv has enough trailing space.

However, only realtek-smi actually allocated this chip_data space.
Do likewise in realtek-mdio to fix out-of-bounds accesses.

Fixes: aac94001067d ("net: dsa: realtek: add new mdio interface for drivers")
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/net/dsa/realtek/realtek-mdio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/dsa/realtek/realtek-mdio.c b/drivers/net/dsa/realtek/realtek-mdio.c
index 3e54fac5f902..3b22d3f7ad99 100644
--- a/drivers/net/dsa/realtek/realtek-mdio.c
+++ b/drivers/net/dsa/realtek/realtek-mdio.c
@@ -152,7 +152,7 @@ static int realtek_mdio_probe(struct mdio_device *mdiodev)
 	if (!var)
 		return -EINVAL;
 
-	priv = devm_kzalloc(&mdiodev->dev, sizeof(*priv), GFP_KERNEL);
+	priv = devm_kzalloc(&mdiodev->dev, sizeof(*priv) + var->chip_data_sz, GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
-- 
2.30.2