[PATCH net v2] net: phy: dp83822: Fix NULL pointer dereference on DP83825 devices

[PATCH net v2] net: phy: dp83822: Fix NULL pointer dereference on DP83825 devices

[Tomas Paukrt]

The probe() function is only used for DP83822 and DP83826 PHY,
leaving the private data pointer uninitialized for the DP83825 models
which causes a NULL pointer dereference in the recently introduced/changed
functions dp8382x_config_init() and dp83822_set_wol().

Add the dp8382x_probe() function, so all PHY models will have a valid
private data pointer to fix this issue and also prevent similar issues
in the future.

Fixes: 9ef9ecfa9e9f ("net: phy: dp8382x: keep WOL settings across suspends")
Signed-off-by: Tomas Paukrt <tomaspaukrt@email.cz>
---
Changes since v1:
- Reused the newly introduced function in dp83822_probe() and dp83826_probe()
---
 drivers/net/phy/dp83822.c | 35 ++++++++++++++++++++++-------------
 1 file changed, 22 insertions(+), 13 deletions(-)

diff --git a/drivers/net/phy/dp83822.c b/drivers/net/phy/dp83822.c
index efeb643..fc247f4 100644
--- a/drivers/net/phy/dp83822.c
+++ b/drivers/net/phy/dp83822.c
@@ -271,8 +271,7 @@ static int dp83822_config_intr(struct phy_device *phydev)
 				DP83822_ENERGY_DET_INT_EN |
 				DP83822_LINK_QUAL_INT_EN);

-		/* Private data pointer is NULL on DP83825 */
-		if (!dp83822 || !dp83822->fx_enabled)
+		if (!dp83822->fx_enabled)
 			misr_status |= DP83822_ANEG_COMPLETE_INT_EN |
 				       DP83822_DUP_MODE_CHANGE_INT_EN |
 				       DP83822_SPEED_CHANGED_INT_EN;
@@ -292,8 +291,7 @@ static int dp83822_config_intr(struct phy_device *phydev)
 				DP83822_PAGE_RX_INT_EN |
 				DP83822_EEE_ERROR_CHANGE_INT_EN);

-		/* Private data pointer is NULL on DP83825 */
-		if (!dp83822 || !dp83822->fx_enabled)
+		if (!dp83822->fx_enabled)
 			misr_status |= DP83822_ANEG_ERR_INT_EN |
 				       DP83822_WOL_PKT_INT_EN;

@@ -691,10 +689,9 @@ static int dp83822_read_straps(struct phy_device *phydev)
 	return 0;
 }

-static int dp83822_probe(struct phy_device *phydev)
+static int dp8382x_probe(struct phy_device *phydev)
 {
 	struct dp83822_private *dp83822;
-	int ret;

 	dp83822 = devm_kzalloc(&phydev->mdio.dev, sizeof(*dp83822),
 			       GFP_KERNEL);
@@ -703,6 +700,20 @@ static int dp83822_probe(struct phy_device *phydev)

 	phydev->priv = dp83822;

+	return 0;
+}
+
+static int dp83822_probe(struct phy_device *phydev)
+{
+	struct dp83822_private *dp83822;
+	int ret;
+
+	ret = dp8382x_probe(phydev);
+	if (ret)
+		return ret;
+
+	dp83822 = phydev->priv;
+
 	ret = dp83822_read_straps(phydev);
 	if (ret)
 		return ret;
@@ -717,14 +728,11 @@ static int dp83822_probe(struct phy_device *phydev)

 static int dp83826_probe(struct phy_device *phydev)
 {
-	struct dp83822_private *dp83822;
-
-	dp83822 = devm_kzalloc(&phydev->mdio.dev, sizeof(*dp83822),
-			       GFP_KERNEL);
-	if (!dp83822)
-		return -ENOMEM;
+	int ret;

-	phydev->priv = dp83822;
+	ret = dp8382x_probe(phydev);
+	if (ret)
+		return ret;

 	dp83826_of_init(phydev);

@@ -795,6 +803,7 @@ static int dp83822_resume(struct phy_device *phydev)
 		PHY_ID_MATCH_MODEL(_id),			\
 		.name		= (_name),			\
 		/* PHY_BASIC_FEATURES */			\
+		.probe          = dp8382x_probe,		\
 		.soft_reset	= dp83822_phy_reset,		\
 		.config_init	= dp8382x_config_init,		\
 		.get_wol = dp83822_get_wol,			\
--
2.7.4

Re: [PATCH net v2] net: phy: dp83822: Fix NULL pointer dereference on DP83825 devices

[Maxime Chevallier]

On Fri, 06 Sep 2024 12:52:40 +0200 (CEST)
"Tomas Paukrt" <tomaspaukrt@email.cz> wrote:

> The probe() function is only used for DP83822 and DP83826 PHY,
> leaving the private data pointer uninitialized for the DP83825 models
> which causes a NULL pointer dereference in the recently introduced/changed
> functions dp8382x_config_init() and dp83822_set_wol().
> 
> Add the dp8382x_probe() function, so all PHY models will have a valid
> private data pointer to fix this issue and also prevent similar issues
> in the future.
> 
> Fixes: 9ef9ecfa9e9f ("net: phy: dp8382x: keep WOL settings across suspends")
> Signed-off-by: Tomas Paukrt <tomaspaukrt@email.cz>

That looks OK to me. Note that you must wait 24h between iterations,
to give everyone a chance to review.

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Thanks,

Maxime

Re: [PATCH net v2] net: phy: dp83822: Fix NULL pointer dereference on DP83825 devices

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 06 Sep 2024 12:52:40 +0200 (CEST) you wrote:
> The probe() function is only used for DP83822 and DP83826 PHY,
> leaving the private data pointer uninitialized for the DP83825 models
> which causes a NULL pointer dereference in the recently introduced/changed
> functions dp8382x_config_init() and dp83822_set_wol().
> 
> Add the dp8382x_probe() function, so all PHY models will have a valid
> private data pointer to fix this issue and also prevent similar issues
> in the future.
> 
> [...]

Here is the summary with links:
  - [net,v2] net: phy: dp83822: Fix NULL pointer dereference on DP83825 devices
    https://git.kernel.org/netdev/net/c/3f62ea572b3e

You are awesome, thank you!
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