From 04cec690b1fd9d1c4c314b91a10d8c68a3acfe18 Mon Sep 17 00:00:00 2001 From: Jameson Thies Date: Tue, 25 Aug 2026 23:45:45 +0000 Subject: [PATCH] usb: typec: ucsi: displayport: Fix OOB altmode array index The UCSI displayport driver indexes the connector's port altmode array with the GET_CURRENT_CAM response after checking it is not 0xff. The port altmode array is UCSI_MAX_ALTMODES elements long. If the PPM returns an invalid GET_CURRENT_CAM response above UCSI_MAX_ALTMODES and not equal to 0xff, the kernel may crash with an array index OOB error. Update the UCSI displayport driver to verify the current cam is less than UCSI_MAX_ALTMODES before accessing the port altmode array. Fixes: af8622f6a585 ("usb: typec: ucsi: Support for DisplayPort alt mode") Cc: stable@vger.kernel.org Signed-off-by: Jameson Thies Reviewed-by: Benson Leung Link: https://patch.msgid.link/20260825234545.2076049-1-jthies@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/typec/ucsi/displayport.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c index 7067f2561b84..8d2032d0762c 100644 --- a/drivers/usb/typec/ucsi/displayport.c +++ b/drivers/usb/typec/ucsi/displayport.c @@ -74,7 +74,7 @@ static int ucsi_displayport_enter(struct typec_altmode *alt, u32 *vdo) cur = 0xff; } - if (cur != 0xff) { + if (cur < UCSI_MAX_ALTMODES) { ret = dp->con->port_altmode[cur] == alt ? 0 : -EBUSY; goto err_unlock; }