[PATCH 4.9 44/70] gpio: ml-ioh: Fix buffer underwrite on probe error path

Greg Kroah-Hartman
2018-09-17T22:59:52Z

From: Anton Vasilyev <vasilyev@ispras.ru>

[ 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>
---
drivers/gpio/gpio-ml-ioh.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpio/gpio-ml-ioh.c
+++ b/drivers/gpio/gpio-ml-ioh.c
@@ -495,9 +495,10 @@ err_irq_alloc_descs:

chip = chip_save;
err_gpiochip_add:
+ chip = chip_save;
while (--i >= 0) {
- chip--;
gpiochip_remove(&chip->gpio);
+ chip++;
}
kfree(chip_save);