[v4,1/4] usb: typec: ucsi: Fix null pointer dereference in trace

Commit Message

Jameson Thies May 10, 2024, 6:43 p.m. UTC

From: Abhishek Pandit-Subedi <[e-mail]>

ucsi_register_altmode checks IS_ERR for the alt pointer and treats
NULL as valid. When CONFIG_TYPEC_DP_ALTMODE is not enabled,
ucsi_register_displayport returns NULL which causes a NULL pointer
dereference in trace. Rather than return NULL, call
typec_port_register_altmode to register DisplayPort alternate mode
as a non-controllable mode when CONFIG_TYPEC_DP_ALTMODE is not enabled.

Reviewed-by: Benson Leung <[e-mail]>
Reviewed-by: Heikki Krogerus <[e-mail]>
Signed-off-by: Jameson Thies <[e-mail]>
Signed-off-by: Abhishek Pandit-Subedi <[e-mail]>
---
Changes in V4:
- Updated commit message.

Changes in V3:
- Returns typec_port_register_altmode call from
ucsi_register_displayport when CONFIG_TYPEC_DP_ALTMODE is not enabled.
Updated commit message.

Changes in V2:
- Checks for error response from ucsi_register_displayport when
registering DisplayPort alternate mode.

 drivers/usb/typec/ucsi/ucsi.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Jameson Thies May 10, 2024, 7:46 p.m. UTC | #1

Hey everyone.
Benson let me know that the submitter should be listed in the last
Signed-off-by line. This is out of order in patch 1/4 and 2/4. My bad,
I'll send out a v5 series fixing this. Sorry about all the email.

Thanks,
Jameson

Patch

diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
index c4d103db9d0f8..f66224a270bc6 100644
--- a/drivers/usb/typec/ucsi/ucsi.h
+++ b/drivers/usb/typec/ucsi/ucsi.h
@@ -496,7 +496,7 @@  ucsi_register_displayport(struct ucsi_connector *con,
 			  bool override, int offset,
 			  struct typec_altmode_desc *desc)
 {
-	return NULL;
+	return typec_port_register_altmode(con->port, desc);
 }
 
 static inline void