HID: cp2112: prevent a buffer overflow in cp2112_xfer()

Smatch warnings:
drivers/hid/hid-cp2112.c:793 cp2112_xfer() error: __memcpy()
'data->block[1]' too small (33 vs 255)
drivers/hid/hid-cp2112.c:793 cp2112_xfer() error: __memcpy() 'buf' too
small (64 vs 255)

The 'read_length' variable is provided by 'data->block[0]' which comes
from user and it(read_length) can take a value between 0-255. Add an
upper bound to 'read_length' variable to prevent a buffer overflow in
memcpy().

Fixes: 542134c037 ("HID: cp2112: Fix I2C_BLOCK_DATA transactions")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Harshit Mogalapalli 2022-06-08 05:26:09 -07:00 committed by Jiri Kosina
parent db925d8090
commit 381583845d

View File

@ -790,6 +790,11 @@ static int cp2112_xfer(struct i2c_adapter *adap, u16 addr,
data->word = le16_to_cpup((__le16 *)buf);
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
if (read_length > I2C_SMBUS_BLOCK_MAX) {
ret = -EINVAL;
goto power_normal;
}
memcpy(data->block + 1, buf, read_length);
break;
case I2C_SMBUS_BLOCK_DATA: