[PATCH 6.12 197/242] usb: typec: ucsi: validate connector number in ucsi_notify_common()

Greg Kroah-Hartman
2026-04-08T18:47:49Z

From: Nathan Rebello <nathan.c.rebello@gmail.com>

commit d2d8c17ac01a1b1f638ea5d340a884ccc5015186 upstream.

The connector number extracted from CCI via UCSI_CCI_CONNECTOR() is a
7-bit field (0-127) that is used to index into the connector array in
ucsi_connector_change(). However, the array is only allocated for the
number of connectors reported by the device (typically 2-4 entries).

A malicious or malfunctioning device could report an out-of-range
connector number in the CCI, causing an out-of-bounds array access in
ucsi_connector_change().

Add a bounds check in ucsi_notify_common(), the central point where CCI
is parsed after arriving from hardware, so that bogus connector numbers
are rejected before they propagate further.

Fixes: bdc62f2bae8f ("usb: typec: ucsi: Simplified registration and I/O API")
Cc: stable <stable@kernel.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Nathan Rebello <nathan.c.rebello@gmail.com>
Link: https://patch.msgid.link/20260313222453.123-1-nathan.c.rebello@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/typec/ucsi/ucsi.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -42,8 +42,13 @@ void ucsi_notify_common(struct ucsi *ucs
if (cci & UCSI_CCI_BUSY)
return;

- if (UCSI_CCI_CONNECTOR(cci))
- ucsi_connector_change(ucsi, UCSI_CCI_CONNECTOR(cci));
+ if (UCSI_CCI_CONNECTOR(cci)) {
+ if (UCSI_CCI_CONNECTOR(cci) <= ucsi->cap.num_connectors)
+ ucsi_connector_change(ucsi, UCSI_CCI_CONNECTOR(cci));
+ else
+ dev_err(ucsi->dev, "bogus connector number in CCI: %lu\n",
+ UCSI_CCI_CONNECTOR(cci));
+ }

if (cci & UCSI_CCI_ACK_COMPLETE &&
test_and_clear_bit(ACK_PENDING, &ucsi->flags))