pinctrl: at91: Fix possible out-of-boundary access

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@linux.intel.com>
Closes: https://lore.kernel.org/r/202505052343.UHF1Zo93-lkp@intel.com/
Link: https://lore.kernel.org/20250508200807.1384558-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/pinctrl/pinctrl-at91.c b/drivers/pinctrl/pinctrl-at91.c
index 442dd8c80b650c4d42adfc07d8898aa946c302ae..6c2727bd55bc3a1dda388e039bc207448dd7d30d 100644 (file)
--- 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);