[patch] gpiolib: potential oops on failure path

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

If anon_inode_getfd() fails then "i" is set to GPIOHANDLES_MAX.  It
means that we will read beyond the end of the array and dereference an
invalid pointer.

Fixes: d7c51b47ac11 ('gpio: userspace ABI for reading/writing GPIO lines')
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 8b3db59..8578b7f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -495,6 +495,8 @@ static int linehandle_create(struct gpio_device *gdev, void __user *ip)
 	return 0;
 
 out_free_descs:
+	if (i == GPIOHANDLES_MAX)
+		i--;
 	for (; i >= 0; i--)
 		gpiod_free(lh->descs[i]);
 	kfree(lh->label);
--
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