usb: typec: ucsi: Fix null pointer dereference in ucsi_sync_control_common

Add missing null check for cci parameter before dereferencing it in
ucsi_sync_control_common(). The function can be called with cci=NULL
from ucsi_acknowledge(), which leads to a null pointer dereference
when accessing *cci in the condition check.

The crash occurs because the code checks if cci is not null before
calling ucsi->ops->read_cci(ucsi, cci), but then immediately
dereferences cci without a null check in the following condition:
(*cci & UCSI_CCI_COMMAND_COMPLETE).

KASAN trace:
  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
  RIP: 0010:ucsi_sync_control_common+0x2ae/0x4e0 [typec_ucsi]

Cc: stable <stable@kernel.org>
Fixes: 667ecac55861 ("usb: typec: ucsi: return CCI and message from sync_control callback")
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
Link: https://patch.msgid.link/20251216122210.5457-1-superm1@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
index 9b3df776137a17e569588d41ee437a778342146e..7129973f19e7eb7163a43797ca9f324af6242c4f 100644 (file)
--- a/drivers/usb/typec/ucsi/ucsi.c
+++ b/drivers/usb/typec/ucsi/ucsi.c
@@ -97,7 +97,7 @@ out_clear_bit:
        if (!ret && cci)
                ret = ucsi->ops->read_cci(ucsi, cci);
 
-       if (!ret && ucsi->message_in_size > 0 &&
+       if (!ret && cci && ucsi->message_in_size > 0 &&
            (*cci & UCSI_CCI_COMMAND_COMPLETE))
                ret = ucsi->ops->read_message_in(ucsi, ucsi->message_in,
                                                 ucsi->message_in_size);