[PATCH] leds:lm3697:Fix out-of-bound access

[Gabriel David]

If both led banks aren't used in device tree,
an out-of-bounds condition in lm3697_init occurs
because of the for loop assuming that all the banks are used.
Fix it by adding a variable that contains the number of used banks.

Signed-off-by: Gabriel David <ultracoolguy@xxxxxxxxxxxx>
---
 drivers/leds/leds-lm3697.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/leds/leds-lm3697.c b/drivers/leds/leds-lm3697.c
index 024983088d59..a3c44b4c9072 100644
--- a/drivers/leds/leds-lm3697.c
+++ b/drivers/leds/leds-lm3697.c
@@ -78,8 +78,9 @@ struct lm3697 {
 	struct mutex lock;

 	int bank_cfg;
+	int num_banks;

-	struct lm3697_led leds[];
+	struct lm3697_led banks[];
 };

 static const struct reg_default lm3697_reg_defs[] = {
@@ -180,8 +181,8 @@ static int lm3697_init(struct lm3697 *priv)
 	if (ret)
 		dev_err(&priv->client->dev, "Cannot write OUTPUT config\n");

-	for (i = 0; i < LM3697_MAX_CONTROL_BANKS; i++) {
-		led = &priv->leds[i];
+	for (i = 0; i < priv->num_banks; i++) {
+		led = &priv->banks[i];
 		ret = ti_lmu_common_set_ramp(&led->lmu_data);
 		if (ret)
 			dev_err(&priv->client->dev, "Setting the ramp rate failed\n");
@@ -228,7 +229,7 @@ static int lm3697_probe_dt(struct lm3697 *priv)
 			goto child_out;
 		}

-		led = &priv->leds[i];
+		led = &priv->banks[i];

 		ret = ti_lmu_common_get_brt_res(&priv->client->dev,
 						child, &led->lmu_data);
@@ -307,16 +308,16 @@ static int lm3697_probe(struct i2c_client *client,
 	int ret;

 	count = device_get_child_node_count(&client->dev);
-	if (!count) {
-		dev_err(&client->dev, "LEDs are not defined in device tree!");
-		return -ENODEV;
-	}
+	if (!count || count > LM3697_MAX_CONTROL_BANKS)
+		return -EINVAL;

-	led = devm_kzalloc(&client->dev, struct_size(led, leds, count),
+	led = devm_kzalloc(&client->dev, struct_size(led, banks, count),
 			   GFP_KERNEL);
 	if (!led)
 		return -ENOMEM;

+	led->num_banks = count;
+
 	mutex_init(&led->lock);
 	i2c_set_clientdata(client, led);

--
2.28.0


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