[PATCH v1 1/1] pinctrl: at91: Fix possible out-of-boundary access

[Andy Shevchenko]

at91_gpio_probe() doesn't check that given OF alias is not available or
something went wrong when trying to get it. This might have consequences
when accessing gpio_chips array with that value as an index. Note, that
BUG() can be compiled out and hence won't actually perform the required
checks.

Fixes: 6732ae5cb47c ("ARM: at91: add pinctrl support")
Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
---
 drivers/pinctrl/pinctrl-at91.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/pinctrl/pinctrl-at91.c b/drivers/pinctrl/pinctrl-at91.c
index 442dd8c80b65..6c2727bd55bc 100644
--- a/drivers/pinctrl/pinctrl-at91.c
+++ b/drivers/pinctrl/pinctrl-at91.c
@@ -1822,12 +1822,16 @@ static int at91_gpio_probe(struct platform_device *pdev)
 	struct at91_gpio_chip *at91_chip = NULL;
 	struct gpio_chip *chip;
 	struct pinctrl_gpio_range *range;
+	int alias_idx;
 	int ret = 0;
 	int irq, i;
-	int alias_idx = of_alias_get_id(np, "gpio");
 	uint32_t ngpio;
 	char **names;
 
+	alias_idx = of_alias_get_id(np, "gpio");
+	if (alias_idx < 0)
+		return alias_idx;
+
 	BUG_ON(alias_idx >= ARRAY_SIZE(gpio_chips));
 	if (gpio_chips[alias_idx])
 		return dev_err_probe(dev, -EBUSY, "%d slot is occupied.\n", alias_idx);
-- 
2.47.2