In watchdog_open(), data is initialized as NULL.
After the loop "list_for_each_entry" on lines 1302-1307,
data may not be assigned, thus data is still NULL.
In this case, data is used on line 1310:
watchdog_is_open = test_and_set_bit(0, &data->watchdog_is_open);
and on line 1317：
kref_get(&data->kref);
and on line 1326:
watchdog_enable(data);
Thus, possible null-pointer dereferences may occur.
To fix these bugs, data is checked after the loop.
If it is NULL, the mutex lock is released and -EINVAL is returned.
These bugs are found by a static analysis tool STCheck written by us.
Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/hwmon/w83793.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/hwmon/w83793.c b/drivers/hwmon/w83793.c
index 46f5dfec8d0a..f299716d5d94 100644
--- a/drivers/hwmon/w83793.c
+++ b/drivers/hwmon/w83793.c
@@ -1306,6 +1306,11 @@ static int watchdog_open(struct inode *inode, struct
file *filp)
}
}
+ if (!data) {
+ mutex_unlock(&watchdog_data_mutex);
+ return -EINVAL;
+ }
+
/* Check, if device is already open */
watchdog_is_open = test_and_set_bit(0, &data->watchdog_is_open);
--
2.17.0
