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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 11/73] gpio: sysfs: Obey valid_mask
Date:   Mon, 19 Apr 2021 15:06:02 +0200
Message-Id: <20210419130524.184955487@linuxfoundation.org>
In-Reply-To: <20210419130523.802169214@linuxfoundation.org>
References: <20210419130523.802169214@linuxfoundation.org>
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From: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>

[ Upstream commit 23cf00ddd2e1aacf1873e43f5e0c519c120daf7a ]

Do not allow exporting GPIOs which are set invalid
by the driver's valid mask.

Fixes: 726cb3ba4969 ("gpiolib: Support 'gpio-reserved-ranges' property")
Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpio/gpiolib-sysfs.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index fbf6b1a0a4fa..558cd900d399 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -457,6 +457,8 @@ static ssize_t export_store(struct class *class,
 	long			gpio;
 	struct gpio_desc	*desc;
 	int			status;
+	struct gpio_chip	*gc;
+	int			offset;
 
 	status = kstrtol(buf, 0, &gpio);
 	if (status < 0)
@@ -468,6 +470,12 @@ static ssize_t export_store(struct class *class,
 		pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
 		return -EINVAL;
 	}
+	gc = desc->gdev->chip;
+	offset = gpio_chip_hwgpio(desc);
+	if (!gpiochip_line_is_valid(gc, offset)) {
+		pr_warn("%s: GPIO %ld masked\n", __func__, gpio);
+		return -EINVAL;
+	}
 
 	/* No extra locking here; FLAG_SYSFS just signifies that the
 	 * request and export were done by on behalf of userspace, so
-- 
2.30.2