gpio: stm32: check result of ofnode_phandle_args

Add test on the size of ofnode_phandle_args result to avoid access
to uninitialized elements in args[] field.

This patch avoids the issue when gpio-ranges cell size is not 3 as
expected, for example:
	gpio-ranges = <&pinctrl 0>;
instead of
	gpio-ranges = <&pinctrl 0 112 16>;

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>

diff --git a/drivers/gpio/stm32_gpio.c b/drivers/gpio/stm32_gpio.c
index aa70b1d..473e364 100644 (file)
--- a/drivers/gpio/stm32_gpio.c
+++ b/drivers/gpio/stm32_gpio.c
@@ -295,6 +295,9 @@ static int gpio_stm32_probe(struct udevice *dev)
        ret = dev_read_phandle_with_args(dev, "gpio-ranges",
                                         NULL, 3, i, &args);
 
+       if (!ret && args.args_count < 3)
+               return -EINVAL;
+
        if (ret == -ENOENT) {
                uc_priv->gpio_count = STM32_GPIOS_PER_BANK;
                priv->gpio_range = GENMASK(STM32_GPIOS_PER_BANK - 1, 0);
@@ -308,6 +311,8 @@ static int gpio_stm32_probe(struct udevice *dev)
 
                ret = dev_read_phandle_with_args(dev, "gpio-ranges", NULL, 3,
                                                 ++i, &args);
+               if (!ret && args.args_count < 3)
+                       return -EINVAL;
        }
 
        dev_dbg(dev, "addr = 0x%p bank_name = %s gpio_count = %d gpio_range = 0x%x\n",