Commit ae11f04b authored by Badhri Jagan Sridharan's avatar Badhri Jagan Sridharan Committed by Greg Kroah-Hartman
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usb: typec: tcpm: Check for port partner validity before consuming it 



typec_register_partner() does not guarantee partner registration
to always succeed. In the event of failure, port->partner is set
to the error value or NULL. Given that port->partner validity is
not checked, this results in the following crash:

Unable to handle kernel NULL pointer dereference at virtual address xx
 pc : run_state_machine+0x1bc8/0x1c08
 lr : run_state_machine+0x1b90/0x1c08
..
 Call trace:
   run_state_machine+0x1bc8/0x1c08
   tcpm_state_machine_work+0x94/0xe4
   kthread_worker_fn+0x118/0x328
   kthread+0x1d0/0x23c
   ret_from_fork+0x10/0x20

To prevent the crash, check for port->partner validity before
derefencing it in all the call sites.

Cc: stable@vger.kernel.org
Fixes: c97cd0b4 ("usb: typec: tcpm: set initial svdm version based on pd revision")
Signed-off-by: default avatarBadhri Jagan Sridharan <badhri@google.com>
Reviewed-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: default avatarDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20240427202812.3435268-1-badhri@google.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent cdc9946e

drivers/usb/typec/tcpm/tcpm.c

+23 −7
Original line number Diff line number Diff line
@@ -1584,6 +1584,7 @@ static void svdm_consume_identity(struct tcpm_port *port, const u32 *p, int cnt) 
	port->partner_ident.cert_stat = p[VDO_INDEX_CSTAT];

	port->partner_ident.product = product;



	if (port->partner)

		typec_partner_set_identity(port->partner);



	tcpm_log(port, "Identity: %04x:%04x.%04x",
@@ -1746,6 +1747,9 @@ static void tcpm_register_partner_altmodes(struct tcpm_port *port) 
	struct typec_altmode *altmode;

	int i;



	if (!port->partner)

		return;



	for (i = 0; i < modep->altmodes; i++) {

		altmode = typec_partner_register_altmode(port->partner,

						&modep->altmode_desc[i]);
@@ -4238,7 +4242,10 @@ static int tcpm_init_vconn(struct tcpm_port *port) 


static void tcpm_typec_connect(struct tcpm_port *port)

{

	struct typec_partner *partner;



	if (!port->connected) {

		port->connected = true;

		/* Make sure we don't report stale identity information */

		memset(&port->partner_ident, 0, sizeof(port->partner_ident));

		port->partner_desc.usb_pd = port->pd_capable;
@@ -4248,9 +4255,13 @@ static void tcpm_typec_connect(struct tcpm_port *port) 
			port->partner_desc.accessory = TYPEC_ACCESSORY_AUDIO;

		else

			port->partner_desc.accessory = TYPEC_ACCESSORY_NONE;

		port->partner = typec_register_partner(port->typec_port,

						       &port->partner_desc);

		port->connected = true;

		partner = typec_register_partner(port->typec_port, &port->partner_desc);

		if (IS_ERR(partner)) {

			dev_err(port->dev, "Failed to register partner (%ld)\n", PTR_ERR(partner));

			return;

		}



		port->partner = partner;

		typec_partner_set_usb_power_delivery(port->partner, port->partner_pd);

	}

}
@@ -4330,9 +4341,11 @@ static void tcpm_typec_disconnect(struct tcpm_port *port) 
	port->plug_prime = NULL;

	port->cable = NULL;

	if (port->connected) {

		if (port->partner) {

			typec_partner_set_usb_power_delivery(port->partner, NULL);

			typec_unregister_partner(port->partner);

			port->partner = NULL;

		}

		port->connected = false;

	}

}
@@ -4556,6 +4569,9 @@ static enum typec_cc_status tcpm_pwr_opmode_to_rp(enum typec_pwr_opmode opmode) 


static void tcpm_set_initial_svdm_version(struct tcpm_port *port)

{

	if (!port->partner)

		return;



	switch (port->negotiated_rev) {

	case PD_REV30:

		break;