leds: lm3697: Fix out-of-bound access

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@tutanota.com>
[removed extra rename, minor tweaks]
Signed-off-by: Pavel Machek <pavel@ucw.cz>
Cc: stable@kernel.org

diff --git a/drivers/leds/leds-lm3697.c b/drivers/leds/leds-lm3697.c
index 64c0794..7d216cd 100644 (file)
--- a/drivers/leds/leds-lm3697.c
+++ b/drivers/leds/leds-lm3697.c
@@ -78,6 +78,7 @@ struct lm3697 {
        struct mutex lock;
 
        int bank_cfg;
+       int num_banks;
 
        struct lm3697_led leds[];
 };
@@ -180,7 +181,7 @@ static int lm3697_init(struct lm3697 *priv)
        if (ret)
                dev_err(dev, "Cannot write OUTPUT config\n");
 
-       for (i = 0; i < LM3697_MAX_CONTROL_BANKS; i++) {
+       for (i = 0; i < priv->num_banks; i++) {
                led = &priv->leds[i];
                ret = ti_lmu_common_set_ramp(&led->lmu_data);
                if (ret)
@@ -301,8 +302,8 @@ static int lm3697_probe(struct i2c_client *client,
        int ret;
 
        count = device_get_child_node_count(dev);
-       if (!count) {
-               dev_err(dev, "LEDs are not defined in device tree!");
+       if (!count || count > LM3697_MAX_CONTROL_BANKS) {
+               dev_err(dev, "Strange device tree!");
                return -ENODEV;
        }
 
@@ -315,6 +316,7 @@ static int lm3697_probe(struct i2c_client *client,
 
        led->client = client;
        led->dev = dev;
+       led->num_banks = count;
        led->regmap = devm_regmap_init_i2c(client, &lm3697_regmap_config);
        if (IS_ERR(led->regmap)) {
                ret = PTR_ERR(led->regmap);