On Sat, Apr 27, 2024 at 1:18 PM Badhri Jagan Sridharan badhri@google.com wrote:
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 00000000000003c0 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: c97cd0b4b54e ("usb: typec: tcpm: set initial svdm version based on pd revision") Signed-off-by: Badhri Jagan Sridharan badhri@google.com
drivers/usb/typec/tcpm/tcpm.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index ab6ed6111ed0..454165776797 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -4,7 +4,6 @@
- USB Power Delivery protocol stack.
*/
Unintentionally removed a blank line. Please ignore this version - v2. Sent v3. Apologies !
#include <linux/completion.h> #include <linux/debugfs.h> #include <linux/device.h> @@ -1580,7 +1579,8 @@ 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),@@ -1742,6 +1742,9 @@ 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]);@@ -4231,7 +4234,10 @@ 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;@@ -4241,9 +4247,13 @@ 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); }} @@ -4323,9 +4333,11 @@ 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; }} @@ -4549,6 +4561,9 @@ 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;base-commit: 3f12222a4bebeb13ce06ddecc1610ad32fa835dd
2.44.0.769.g3c40516874-goog