On Fri, Oct 20, 2023 at 01:21:32AM +0000, Jimmy Hu wrote:
> It is possible that typec_register_partner() returns ERR_PTR on failure.
> When port->partner is an error, a NULL pointer dereference may occur as
> shown below.
>
> [91222.095236][ T319] typec port0: failed to register partner (-17)
> ...
> [91225.061491][ T319] Unable to handle kernel NULL pointer dereference
> at virtual address 000000000000039f
> [91225.274642][ T319] pc : tcpm_pd_data_request+0x310/0x13fc
> [91225.274646][ T319] lr : tcpm_pd_data_request+0x298/0x13fc
> [91225.308067][ T319] Call trace:
> [91225.308070][ T319] tcpm_pd_data_request+0x310/0x13fc
> [91225.308073][ T319] tcpm_pd_rx_handler+0x100/0x9e8
> [91225.355900][ T319] kthread_worker_fn+0x178/0x58c
> [91225.355902][ T319] kthread+0x150/0x200
> [91225.355905][ T319] ret_from_fork+0x10/0x30
>
> Add a check for port->partner to avoid dereferencing a NULL pointer.
>
> Fixes: 5e1d4c49fbc8 ("usb: typec: tcpm: Determine common SVDM Version")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Jimmy Hu <hhhuuu@xxxxxxxxxx>
Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> drivers/usb/typec/tcpm/tcpm.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 6e843c511b85..792ec4ac7d8d 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -1625,6 +1625,9 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
> if (PD_VDO_VID(p[0]) != USB_SID_PD)
> break;
>
> + if (IS_ERR_OR_NULL(port->partner))
> + break;
> +
> if (PD_VDO_SVDM_VER(p[0]) < svdm_version) {
> typec_partner_set_svdm_version(port->partner,
> PD_VDO_SVDM_VER(p[0]));
--
heikki
