[PATCH 5.15.y 2/2] i2c: cp2615: fix serial string NULL-deref at probe

[Sasha Levin <sashal@kernel.org>]

From: Johan Hovold <johan@kernel.org>

[ Upstream commit aa79f996eb41e95aed85a1bd7f56bcd6a3842008 ]

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>
Reviewed-by: Bence Csókás <bence98@sch.bme.hu>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260309075016.25612-1-johan@kernel.org
Signed-off-by: Sasha Levin <sashal@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 20f8f7c9a8cd4..8e17f32d38c06 100644
--- a/drivers/i2c/busses/i2c-cp2615.c
+++ b/drivers/i2c/busses/i2c-cp2615.c
@@ -298,6 +298,9 @@ 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;
-- 
2.51.0