Re: [PATCH v3 2/2] usb: typec: tipd: fix uninitialized typec_partner_desc in cd321x_update_work()

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

On Wed, Aug 12, 2026 at 09:44:54PM +0530, Radhey Shyam Pandey wrote:
> cd321x_update_work() passes a stack-allocated typec_partner_desc to
> typec_register_partner() after initializing only usb_pd, accessory and
> identity.
> 
> typec_register_partner() copies attach and deattach from the descriptor
> into the partner. With those fields left unset, garbage function pointers
> may be stored and later invoked from typec_partner_link_device() when a USB
> device is linked to the port. Uninitialized pd_revision and usb_capability
> similarly leak stack data through partner sysfs.
> 
> Zero-initialize the descriptor so optional callbacks remain NULL and the
> remaining fields are zero.
> 
> Fixes: 82432bbfb9e8 ("usb: typec: tipd: Handle mode transitions for CD321x")
> Cc: stable@vger.kernel.org # 6.18+
> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
> Changes for v3:
> - Split v2 into separate patches to simplify LTS backporting.
> - Drop Heikki reviewed-by tag as now patch is split.
> 
> Changes for v2:
> - Add  Assisted-by tag.
> - Remove explicit indentity=NULL
> 
> AI code scanning identified this issue; the possible call graph is shown below.
> 
>   USB-C plug event (IRQ)
>     tps6598x_interrupt()
>       tps6598x_handle_plug_event()
>         tps6598x_connect()
>           struct typec_partner_desc desc;     /* bug: attach/deattach unset */
>           desc.usb_pd / .accessory / .identity = ...
>           typec_register_partner(port, &desc)   /* class.c */
>             partner->attach   = desc->attach;   /* copy stack garbage */
>             partner->deattach = desc->deattach;
>             [if port->usb2_dev || port->usb3_dev already set]
>               typec_partner_link_device(partner, dev)
>                 if (partner->attach)
>                   partner->attach(partner, dev)  /* indirect call via bad ptr */
> ---
>  drivers/usb/typec/tipd/core.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
> index 54ca726c3b15..d99a55063e34 100644
> --- a/drivers/usb/typec/tipd/core.c
> +++ b/drivers/usb/typec/tipd/core.c
> @@ -840,11 +840,10 @@ static void cd321x_update_work(struct work_struct *work)
>  
>  	/* Set up partner if we were previously disconnected (or changed). */
>  	if (!tps->partner) {
> -		struct typec_partner_desc desc;
> +		struct typec_partner_desc desc = { };
>  
>  		desc.usb_pd = is_pd;
>  		desc.accessory = TYPEC_ACCESSORY_NONE; /* XXX: handle accessories */
> -		desc.identity = NULL;
>  
>  		if (desc.usb_pd)
>  			desc.identity = &st.partner_identity;
> -- 
> 2.43.0

-- 
heikki