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Subject[PATCH v2 4/6] leds: netdev trigger: move name length checking to netdev_trig_set_device
Date
It's better to check that size is sane in the function that does the
memcpy'ing and 0-termination to the IFNAMSIZ-sized buffer instead of
relying on callers getting it right. Not rejecting size upfront does
mean we would do the cancel_delayed_work_sync(), but that gets fixed
up by the set_baseline_state() call.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
---
drivers/leds/trigger/ledtrig-netdev.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c
index c35439291424..e4a76ce4e4c7 100644
--- a/drivers/leds/trigger/ledtrig-netdev.c
+++ b/drivers/leds/trigger/ledtrig-netdev.c
@@ -104,9 +104,12 @@ static ssize_t device_name_show(struct device *dev,
return len;
}

-static void netdev_trig_set_device(struct led_netdev_data *trigger_data,
- const char *buf, size_t size)
+static ssize_t netdev_trig_set_device(struct led_netdev_data *trigger_data,
+ const char *buf, size_t size)
{
+ if (size >= IFNAMSIZ)
+ return -EINVAL;
+
if (trigger_data->net_dev) {
dev_put(trigger_data->net_dev);
trigger_data->net_dev = NULL;
@@ -125,6 +128,7 @@ static void netdev_trig_set_device(struct led_netdev_data *trigger_data,
set_bit(NETDEV_LED_MODE_LINKUP, &trigger_data->mode);

trigger_data->last_activity = 0;
+ return 0;
}

static ssize_t device_name_store(struct device *dev,
@@ -133,23 +137,22 @@ static ssize_t device_name_store(struct device *dev,
{
struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev);
size_t orig_size = size;
+ ssize_t ret;

/* Ignore trailing newline */
if (size > 0 && buf[size - 1] == '\n')
size--;
- if (size >= IFNAMSIZ)
- return -EINVAL;

cancel_delayed_work_sync(&trigger_data->work);

spin_lock_bh(&trigger_data->lock);

- netdev_trig_set_device(trigger_data, buf, size);
+ ret = netdev_trig_set_device(trigger_data, buf, size);

set_baseline_state(trigger_data);
spin_unlock_bh(&trigger_data->lock);

- return orig_size;
+ return ret ? ret : orig_size;
}

static DEVICE_ATTR_RW(device_name);
--
2.20.1
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