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usb: typec: tcpm: Check for port partner validity before consuming it

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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: c97cd0b4b5 ("usb: typec: tcpm: set initial svdm version based on pd revision")
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20240427202812.3435268-1-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Badhri Jagan Sridharan 2024-04-27 20:28:12 +00:00 committed by Greg Kroah-Hartman
parent cdc9946ea6
commit ae11f04b45
1 changed files with 23 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/usb/typec/tcpm/tcpm.c
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@ -1584,7 +1584,8 @@ 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;
typec_partner_set_identity(port->partner);
if (port->partner)
typec_partner_set_identity(port->partner);
tcpm_log(port, "Identity: %04x:%04x.%04x",
PD_IDH_VID(vdo),
@ -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) {
typec_partner_set_usb_power_delivery(port->partner, NULL);
typec_unregister_partner(port->partner);
port->partner = NULL;
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;