[PATCH] i2c: cp2615: fix serial string NULL-deref at probe

[Johan Hovold <johan@kernel.org>]

The cp2615 driver uses the USB device serial string as the i2c adapter
name but does not make sure that the string exists.

Verify that the device has a serial number before accessing it to avoid
triggering a NULL-pointer dereference (e.g. with malicious devices).

Fixes: 4a7695429ead ("i2c: cp2615: add i2c driver for Silicon Labs' CP2615 Digital Audio Bridge")
Cc: stable@vger.kernel.org	# 5.13
Cc: Bence Csókás <bence98@sch.bme.hu>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/i2c/busses/i2c-cp2615.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/i2c/busses/i2c-cp2615.c b/drivers/i2c/busses/i2c-cp2615.c
index c1dbf7961a02..951de6249834 100644
--- a/drivers/i2c/busses/i2c-cp2615.c
+++ b/drivers/i2c/busses/i2c-cp2615.c
@@ -297,6 +297,9 @@ cp2615_i2c_probe(struct usb_interface *usbif, const struct usb_device_id *id)
 	if (!adap)
 		return -ENOMEM;
 
+	if (!usbdev->serial)
+		return -EINVAL;
+
 	strscpy(adap->name, usbdev->serial, sizeof(adap->name));
 	adap->owner = THIS_MODULE;
 	adap->dev.parent = &usbif->dev;
-- 
2.52.0