2023-10-20 01:24:28

by Jimmy Hu

Subject: [PATCH v2] usb: typec: tcpm: Fix NULL pointer dereference in tcpm_pd_svdm()

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: [email protected]
Signed-off-by: Jimmy Hu <[email protected]>
---
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]));
--
2.42.0.758.gaed0368e0e-goog

2023-10-30 07:34:17

by Heikki Krogerus

Subject: Re: [PATCH v2] usb: typec: tcpm: Fix NULL pointer dereference in tcpm_pd_svdm()

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: [email protected]
> Signed-off-by: Jimmy Hu <[email protected]>

Acked-by: Heikki Krogerus <[email protected]>

> ---
> 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