Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Sander Vanheule <sander@svanheule.net>
To:     Mark Brown <broonie@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        linux-kernel@vger.kernel.org
Cc:     Andy Shevchenko <andy.shevchenko@gmail.com>,
        Adrew Lunn <andrew@lunn.ch>,
        Sander Vanheule <sander@svanheule.net>
Subject: [PATCH v2 2/2] regmap: mdio: Reject invalid addresses
Date:   Wed,  9 Jun 2021 15:10:04 +0200
Message-Id: <047007e0e9fb596480829f11f8c7e6281d235c70.1623244066.git.sander@svanheule.net>
In-Reply-To: <cover.1623244066.git.sander@svanheule.net>
References: <cover.1623244066.git.sander@svanheule.net>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When an invalid register offset is provided, the upper bits are silently
discarded. Change this to return -ENXIO instead, to help catch potential
bugs.

Signed-off-by: Sander Vanheule <sander@svanheule.net>
---
 drivers/base/regmap/regmap-mdio.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/base/regmap/regmap-mdio.c b/drivers/base/regmap/regmap-mdio.c
index b772b42809e2..6a20201299f5 100644
--- a/drivers/base/regmap/regmap-mdio.c
+++ b/drivers/base/regmap/regmap-mdio.c
@@ -31,14 +31,20 @@ static int regmap_mdio_c22_read(void *context, unsigned int reg, unsigned int *v
 {
 	struct mdio_device *mdio_dev = context;
 
-	return regmap_mdio_read(mdio_dev, reg & REGNUM_C22_MASK, val);
+	if (unlikely(reg & ~REGNUM_C22_MASK))
+		return -ENXIO;
+
+	return regmap_mdio_read(mdio_dev, reg, val);
 }
 
 static int regmap_mdio_c22_write(void *context, unsigned int reg, unsigned int val)
 {
 	struct mdio_device *mdio_dev = context;
 
-	return regmap_mdio_write(mdio_dev, reg & REGNUM_C22_MASK, val);
+	if (unlikely(reg & ~REGNUM_C22_MASK))
+		return -ENXIO;
+
+	return mdiobus_write(mdio_dev->bus, mdio_dev->addr, reg, val);
 }
 
 static const struct regmap_bus regmap_mdio_c22_bus = {
@@ -50,14 +56,20 @@ static int regmap_mdio_c45_read(void *context, unsigned int reg, unsigned int *v
 {
 	struct mdio_device *mdio_dev = context;
 
-	return regmap_mdio_read(mdio_dev, MII_ADDR_C45 | (reg & REGNUM_C45_MASK), val);
+	if (unlikely(reg & ~REGNUM_C45_MASK))
+		return -ENXIO;
+
+	return regmap_mdio_read(mdio_dev, MII_ADDR_C45 | reg, val);
 }
 
 static int regmap_mdio_c45_write(void *context, unsigned int reg, unsigned int val)
 {
 	struct mdio_device *mdio_dev = context;
 
-	return regmap_mdio_write(mdio_dev, MII_ADDR_C45 | (reg & REGNUM_C45_MASK), val);
+	if (unlikely(reg & ~REGNUM_C45_MASK))
+		return -ENXIO;
+
+	return regmap_mdio_write(mdio_dev, MII_ADDR_C45 | reg, val);
 }
 
 static const struct regmap_bus regmap_mdio_c45_bus = {
-- 
2.31.1