linux-kernel - [PATCH v1 1/2] gpiolib: Never return internal error codes to user space

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Date:   Tue, 18 May 2021 18:50:12 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Kent Gibson <warthog618@...il.com>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Suresh Balakrishnan <suresh.balakrishnan@...el.com>
Subject: [PATCH v1 1/2] gpiolib: Never return internal error codes to user space

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>
---
 drivers/gpio/gpiolib-cdev.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index 1631727bf0da..1d8f66880d63 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -331,8 +331,11 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 		}
 
 		ret = gpiod_request(desc, lh->label);
-		if (ret)
+		if (ret) {
+			if (ret == -EPROBE_DEFER)
+				ret = -ENODEV;
 			goto out_free_lh;
+		}
 		lh->descs[i] = desc;
 		linehandle_flags_to_desc_flags(handlereq.flags, &desc->flags);
 
@@ -1379,8 +1382,11 @@ static int linereq_create(struct gpio_device *gdev, void __user *ip)
 		}
 
 		ret = gpiod_request(desc, lr->label);
-		if (ret)
+		if (ret) {
+			if (ret == -EPROBE_DEFER)
+				ret = -ENODEV;
 			goto out_free_linereq;
+		}
 
 		lr->lines[i].desc = desc;
 		flags = gpio_v2_line_config_flags(lc, i);
@@ -1765,8 +1771,11 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip)
 	}
 
 	ret = gpiod_request(desc, le->label);
-	if (ret)
+	if (ret) {
+		if (ret == -EPROBE_DEFER)
+			ret = -ENODEV;
 		goto out_free_le;
+	}
 	le->desc = desc;
 	le->eflags = eflags;
 
-- 
2.30.2