linux-kernel - [PATCH 5.16 128/203] gpiolib: Never return internal error codes to user space

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Date:   Mon, 14 Feb 2022 10:26:12 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Suresh Balakrishnan <suresh.balakrishnan@...el.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.16 128/203] gpiolib: Never return internal error codes to user space

From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

[ Upstream commit 95a4eed7dd5b7c1c3664a626174290686ddbee9f ]

Currently it's possible that character device interface may return
the error codes which are not supposed to be seen by user space.
In this case it's EPROBE_DEFER.

Wrap it to return -ENODEV instead as sysfs does.

Fixes: d7c51b47ac11 ("gpio: userspace ABI for reading/writing GPIO lines")
Fixes: 61f922db7221 ("gpio: userspace ABI for reading GPIO line events")
Fixes: 3c0d9c635ae2 ("gpiolib: cdev: support GPIO_V2_GET_LINE_IOCTL and GPIO_V2_LINE_GET_VALUES_IOCTL")
Reported-by: Suresh Balakrishnan <suresh.balakrishnan@...el.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Signed-off-by: Bartosz Golaszewski <brgl@...ev.pl>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpio/gpiolib-cdev.c  |  6 +++---
 drivers/gpio/gpiolib-sysfs.c |  7 ++-----
 drivers/gpio/gpiolib.h       | 12 ++++++++++++
 3 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index c7b5446d01fd2..ffa0256cad5a0 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -330,7 +330,7 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 			goto out_free_lh;
 		}
 
-		ret = gpiod_request(desc, lh->label);
+		ret = gpiod_request_user(desc, lh->label);
 		if (ret)
 			goto out_free_lh;
 		lh->descs[i] = desc;
@@ -1378,7 +1378,7 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
 			goto out_free_linereq;
 		}
 
-		ret = gpiod_request(desc, lr->label);
+		ret = gpiod_request_user(desc, lr->label);
 		if (ret)
 			goto out_free_linereq;
 
@@ -1764,7 +1764,7 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 		}
 	}
 
-	ret = gpiod_request(desc, le->label);
+	ret = gpiod_request_user(desc, le->label);
 	if (ret)
 		goto out_free_le;
 	le->desc = desc;
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 4098bc7f88b7e..44c1ad51b3fe9 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -475,12 +475,9 @@ static ssize_t export_store(struct class *class,
 	 * they may be undone on its behalf too.
 	 */
 
-	status = gpiod_request(desc, "sysfs");
-	if (status) {
-		if (status == -EPROBE_DEFER)
-			status = -ENODEV;
+	status = gpiod_request_user(desc, "sysfs");
+	if (status)
 		goto done;
-	}
 
 	status = gpiod_set_transitory(desc, false);
 	if (!status) {
diff --git a/drivers/gpio/gpiolib.h b/drivers/gpio/gpiolib.h
index 30bc3f80f83e6..c31f4626915de 100644
--- a/drivers/gpio/gpiolib.h
+++ b/drivers/gpio/gpiolib.h
@@ -135,6 +135,18 @@ struct gpio_desc {
 
 int gpiod_request(struct gpio_desc *desc, const char *label);
 void gpiod_free(struct gpio_desc *desc);
+
+static inline int gpiod_request_user(struct gpio_desc *desc, const char *label)
+{
+	int ret;
+
+	ret = gpiod_request(desc, label);
+	if (ret == -EPROBE_DEFER)
+		ret = -ENODEV;
+
+	return ret;
+}
+
 int gpiod_configure_flags(struct gpio_desc *desc, const char *con_id,
 		unsigned long lflags, enum gpiod_flags dflags);
 int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce);
-- 
2.34.1