pinctrl: add checks for empty function names

This is needed as otherwise we can get the following when
dealing with buggy data in a pinmux driver for
pinmux_search_function:

Unable to handle kernel NULL pointer dereference at virtual
address 00000000
...
PC is at strcmp+0xc/0x34
LR is at pinmux_get+0x350/0x8f4
...

As we need pctldev initialized to call ops->list_functions,
let's initialize it before check_ops calls and pass the
pctldev to the check_ops functions. Do this for both pinmux
and pinconf check_ops functions.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 18 insertions, 18 deletions

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index d9d35fcbfc6b..8fe15cf15ac8 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -583,40 +583,40 @@ struct pinctrl_dev *pinctrl_register(struct pinctrl_desc *pctldesc,
 	if (pctldesc->name == NULL)
 		return NULL;
 
+	pctldev = kzalloc(sizeof(struct pinctrl_dev), GFP_KERNEL);
+	if (pctldev == NULL)
+		return NULL;
+
+	/* Initialize pin control device struct */
+	pctldev->owner = pctldesc->owner;
+	pctldev->desc = pctldesc;
+	pctldev->driver_data = driver_data;
+	INIT_RADIX_TREE(&pctldev->pin_desc_tree, GFP_KERNEL);
+	spin_lock_init(&pctldev->pin_desc_tree_lock);
+	INIT_LIST_HEAD(&pctldev->gpio_ranges);
+	mutex_init(&pctldev->gpio_ranges_lock);
+	pctldev->dev = dev;
+
 	/* If we're implementing pinmuxing, check the ops for sanity */
 	if (pctldesc->pmxops) {
-		ret = pinmux_check_ops(pctldesc->pmxops);
+		ret = pinmux_check_ops(pctldev);
 		if (ret) {
 			pr_err("%s pinmux ops lacks necessary functions\n",
 			       pctldesc->name);
-			return NULL;
+			goto out_err;
 		}
 	}
 
 	/* If we're implementing pinconfig, check the ops for sanity */
 	if (pctldesc->confops) {
-		ret = pinconf_check_ops(pctldesc->confops);
+		ret = pinconf_check_ops(pctldev);
 		if (ret) {
 			pr_err("%s pin config ops lacks necessary functions\n",
 			       pctldesc->name);
-			return NULL;
+			goto out_err;
 		}
 	}
 
-	pctldev = kzalloc(sizeof(struct pinctrl_dev), GFP_KERNEL);
-	if (pctldev == NULL)
-		return NULL;
-
-	/* Initialize pin control device struct */
-	pctldev->owner = pctldesc->owner;
-	pctldev->desc = pctldesc;
-	pctldev->driver_data = driver_data;
-	INIT_RADIX_TREE(&pctldev->pin_desc_tree, GFP_KERNEL);
-	spin_lock_init(&pctldev->pin_desc_tree_lock);
-	INIT_LIST_HEAD(&pctldev->gpio_ranges);
-	mutex_init(&pctldev->gpio_ranges_lock);
-	pctldev->dev = dev;
-
 	/* Register all the pins */
 	pr_debug("try to register %d pins on %s...\n",
 		 pctldesc->npins, pctldesc->name);