If driver read val value sufficient for
(val & 0x08) && (!(val & 0x80)) && ((val & 0x7) == ((val >> 4) & 0x7))
from device then Null pointer dereference occurs.
(It is possible if tmp = 0b0xyz1xyz, where same literals mean same numbers)
Also lm75[] does not serve a purpose anymore after switching to
devm_i2c_new_dummy_device() in w83791d_detect_subclients().
The patch fixes possible NULL pointer dereference by removing lm75[].
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Nadezda Lutovinova <lutovinova@xxxxxxxxx>
---
v2:
- split one file per patch
- remove lm75[] instead of adding checking
---
drivers/hwmon/w83791d.c | 32 ++++++++++++++------------------
1 file changed, 14 insertions(+), 18 deletions(-)
diff --git a/drivers/hwmon/w83791d.c b/drivers/hwmon/w83791d.c
index 37b25a1474c4..b4eae45859c1 100644
--- a/drivers/hwmon/w83791d.c
+++ b/drivers/hwmon/w83791d.c
@@ -273,9 +273,6 @@ struct w83791d_data {
char valid; /* !=0 if following fields are valid */
unsigned long last_updated; /* In jiffies */
- /* array of 2 pointers to subclients */
- struct i2c_client *lm75[2];
-
/* volts */
u8 in[NUMBER_OF_VIN]; /* Register value */
u8 in_max[NUMBER_OF_VIN]; /* Register value */
@@ -1257,7 +1254,6 @@ static const struct attribute_group w83791d_group_fanpwm45 = {
static int w83791d_detect_subclients(struct i2c_client *client)
{
struct i2c_adapter *adapter = client->adapter;
- struct w83791d_data *data = i2c_get_clientdata(client);
int address = client->addr;
int i, id;
u8 val;
@@ -1280,21 +1276,21 @@ static int w83791d_detect_subclients(struct i2c_client *client)
}
val = w83791d_read(client, W83791D_REG_I2C_SUBADDR);
+
+ if (!(val & 0x88) && (val & 0x7) == ((val >> 4) & 0x7)) {
+ dev_err(&client->dev,
+ "duplicate addresses 0x%x, use force_subclient\n",
+ 0x48 + (val & 0x7));
+ return -ENODEV;
+ }
+
if (!(val & 0x08))
- data->lm75[0] = devm_i2c_new_dummy_device(&client->dev, adapter,
- 0x48 + (val & 0x7));
- if (!(val & 0x80)) {
- if (!IS_ERR(data->lm75[0]) &&
- ((val & 0x7) == ((val >> 4) & 0x7))) {
- dev_err(&client->dev,
- "duplicate addresses 0x%x, "
- "use force_subclient\n",
- data->lm75[0]->addr);
- return -ENODEV;
- }
- data->lm75[1] = devm_i2c_new_dummy_device(&client->dev, adapter,
- 0x48 + ((val >> 4) & 0x7));
- }
+ devm_i2c_new_dummy_device(&client->dev, adapter,
+ 0x48 + (val & 0x7));
+
+ if (!(val & 0x80))
+ devm_i2c_new_dummy_device(&client->dev, adapter,
+ 0x48 + ((val >> 4) & 0x7));
return 0;
}
--
2.17.1
