From: Anton Vasilyev <vasilyev@ispras.ru>
Date: Mon, 23 Jul 2018 16:53:30 +0000 (+0300)
Subject: gpio: ml-ioh: Fix buffer underwrite on probe error path
X-Git-Tag: v4.14.71~62
X-Git-Url: http://git.hungrycats.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=acd73639c38c44a24c3892c1e258d5957c58c955;p=linux

gpio: ml-ioh: Fix buffer underwrite on probe error path

[ Upstream commit 4bf4eed44bfe288f459496eaf38089502ef91a79 ]

If ioh_gpio_probe() fails on devm_irq_alloc_descs() then chip may point
to any element of chip_save array, so reverse iteration from pointer chip
may become chip_save[-1] and gpiochip_remove() will operate with wrong
memory.

The patch fix the error path of ioh_gpio_probe() to correctly bypass
chip_save array.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/gpio/gpio-ml-ioh.c b/drivers/gpio/gpio-ml-ioh.c
index 4b80e996d976..1022fe8d09c7 100644
--- a/drivers/gpio/gpio-ml-ioh.c
+++ b/drivers/gpio/gpio-ml-ioh.c
@@ -497,9 +497,10 @@ static int ioh_gpio_probe(struct pci_dev *pdev,
 	return 0;
 
 err_gpiochip_add:
+	chip = chip_save;
 	while (--i >= 0) {
-		chip--;
 		gpiochip_remove(&chip->gpio);
+		chip++;
 	}
 	kfree(chip_save);