From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Wed, 13 May 2026 15:52:55 +0000 (+0200)
Subject: usb: typec: ucsi: validate connector number in ucsi_connector_change()
X-Git-Tag: v7.1-rc6~9^2~27
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=288a81a8507052bcfbf884d39a463c44c42c5fd9;p=thirdparty%2Fkernel%2Flinux.git

usb: typec: ucsi: validate connector number in ucsi_connector_change()

The connector number in a UCSI CCI notification is a 7-bit field
supplied by the PPM.  ucsi_connector_change() uses it to index the
ucsi->connector[] array without checking it against the number of
connectors the PPM reported at init time, so a buggy or malicious PPM
(EC firmware, or an I2C-attached UCSI controller on the ccg / stm32g0 /
glink transports) can drive schedule_work() on memory past the end of
the array.

Reject connector numbers that are zero or exceed cap.num_connectors
before dereferencing the array.

Assisted-by: gkh_clanker_t1000
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Benson Leung <bleung@chromium.org>
Cc: Jameson Thies <jthies@google.com>
Cc: Nathan Rebello <nathan.c.rebello@gmail.com>
Cc: Johan Hovold <johan@kernel.org>
Cc: Pooja Katiyar <pooja.katiyar@intel.com>
Cc: Hsin-Te Yuan <yuanhsinte@chromium.org>
Cc: Abel Vesa <abelvesa@kernel.org>
Cc: stable <stable@kernel.org>
Reviewed-by: Abel Vesa <abel.vesa@oss.qualcomm.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Benson Leung <bleung@chromium.org>
Link: https://patch.msgid.link/2026051351-truck-steadfast-df48@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 5b7ad9e99cb94..539dc706798d5 100644
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -1380,13 +1380,22 @@ out_unlock:
  */
 void ucsi_connector_change(struct ucsi *ucsi, u8 num)
 {
-	struct ucsi_connector *con = &ucsi->connector[num - 1];
+	struct ucsi_connector *con;
 
 	if (!(ucsi->ntfy & UCSI_ENABLE_NTFY_CONNECTOR_CHANGE)) {
 		dev_dbg(ucsi->dev, "Early connector change event\n");
 		return;
 	}
 
+	if (!num || num > ucsi->cap.num_connectors) {
+		dev_warn_ratelimited(ucsi->dev,
+				     "Bogus connector change on %u (max %u)\n",
+				     num, ucsi->cap.num_connectors);
+		return;
+	}
+
+	con = &ucsi->connector[num - 1];
+
 	if (!test_and_set_bit(EVENT_PENDING, &ucsi->flags))
 		schedule_work(&con->work);
 }