linux-kernel - [PATCH net v2] net: dsa: qca8k: fix illegal usage of GPIO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date: Wed, 24 Jan 2024 12:37:04 +0100
From: Michal Vokáč <michal.vokac@...ft.com>
To: Andrew Lunn <andrew@...n.ch>,
	Florian Fainelli <f.fainelli@...il.com>,
	Vladimir Oltean <olteanv@...il.com>,
	"David S. Miller" <davem@...emloft.net>
Cc: Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>,
	Christian Marangi <ansuelsmth@...il.com>,
	"Russell King (Oracle)" <rmk+kernel@...linux.org.uk>,
	Marek Behún <kabel@...nel.org>,
	Christian Lamparter <chunkeey@...il.com>,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	petr.benes@...ft.com,
	Michal Vokáč <michal.vokac@...ft.com>
Subject: [PATCH net v2] net: dsa: qca8k: fix illegal usage of GPIO

When working with GPIO, its direction must be set either when the GPIO is
requested by gpiod_get*() or later on by one of the gpiod_direction_*()
functions. Neither of this is done here which results in undefined
behavior on some systems.

As the reset GPIO is used right after it is requested here, it makes sense
to configure it as GPIOD_OUT_HIGH right away. With that, the following
gpiod_set_value_cansleep(1) becomes redundant and can be safely
removed.

Fixes: a653f2f538f9 ("net: dsa: qca8k: introduce reset via gpio feature")
Signed-off-by: Michal Vokáč <michal.vokac@...ft.com>
---
Changes in v2:
- Remove the now redundant gpiod_set_value_cansleep(1) call.

 drivers/net/dsa/qca/qca8k-8xxx.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/net/dsa/qca/qca8k-8xxx.c b/drivers/net/dsa/qca/qca8k-8xxx.c
index ec57d9d52072..3663de8f2617 100644
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
@@ -2037,13 +2037,11 @@ qca8k_sw_probe(struct mdio_device *mdiodev)
 	priv->dev = &mdiodev->dev;
 	priv->info = of_device_get_match_data(priv->dev);
 
-	priv->reset_gpio = devm_gpiod_get_optional(priv->dev, "reset",
-						   GPIOD_ASIS);
+	priv->reset_gpio = devm_gpiod_get_optional(priv->dev, "reset", GPIOD_OUT_HIGH);
 	if (IS_ERR(priv->reset_gpio))
 		return PTR_ERR(priv->reset_gpio);
 
 	if (priv->reset_gpio) {
-		gpiod_set_value_cansleep(priv->reset_gpio, 1);
 		/* The active low duration must be greater than 10 ms
 		 * and checkpatch.pl wants 20 ms.
 		 */
-- 
2.1.4