2023-05-04 06:06:26

by HaoTien Hsu

[permalink] [raw]
Subject: [PATCH] phy: tegra: xusb: Fix use-after-free issue

From: EJ Hsu <[email protected]>

For the dual-role port, it will assign the phy dev to usb-phy dev and
use the port dev driver as the dev driver of usb-phy.

When we try to destroy the port dev, it will destroy its dev driver
as well. But we did not remove the reference from usb-phy dev. This
might cause the use-after-free issue in KASAN.

Fixes: e8f7d2f409a1 ("phy: tegra: xusb: Add usb-phy support")
Cc: [email protected]

Signed-off-by: EJ Hsu <[email protected]>
Signed-off-by: Haotien Hsu <[email protected]>
---
drivers/phy/tegra/xusb.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c
index 78045bd6c214..515298a9a433 100644
--- a/drivers/phy/tegra/xusb.c
+++ b/drivers/phy/tegra/xusb.c
@@ -563,13 +563,6 @@ static int tegra_xusb_port_init(struct tegra_xusb_port *port,

static void tegra_xusb_port_unregister(struct tegra_xusb_port *port)
{
- if (!IS_ERR_OR_NULL(port->usb_role_sw)) {
- of_platform_depopulate(&port->dev);
- usb_role_switch_unregister(port->usb_role_sw);
- cancel_work_sync(&port->usb_phy_work);
- usb_remove_phy(&port->usb_phy);
- }
-
if (port->ops->remove)
port->ops->remove(port);

@@ -832,6 +825,14 @@ void tegra_xusb_usb2_port_remove(struct tegra_xusb_port *port)
{
struct tegra_xusb_usb2_port *usb2 = to_usb2_port(port);

+ if (!IS_ERR_OR_NULL(port->usb_role_sw)) {
+ of_platform_depopulate(&port->dev);
+ usb_role_switch_unregister(port->usb_role_sw);
+ cancel_work_sync(&port->usb_phy_work);
+ usb_remove_phy(&port->usb_phy);
+ port->usb_phy.dev->driver = NULL;
+ }
+
regulator_put(usb2->supply);
}

--
2.25.1


2023-05-04 09:34:38

by Thierry Reding

[permalink] [raw]
Subject: Re: [PATCH] phy: tegra: xusb: Fix use-after-free issue

On Thu, May 04, 2023 at 01:54:46PM +0800, Haotien Hsu wrote:
> From: EJ Hsu <[email protected]>
>
> For the dual-role port, it will assign the phy dev to usb-phy dev and
> use the port dev driver as the dev driver of usb-phy.
>
> When we try to destroy the port dev, it will destroy its dev driver
> as well. But we did not remove the reference from usb-phy dev. This
> might cause the use-after-free issue in KASAN.
>
> Fixes: e8f7d2f409a1 ("phy: tegra: xusb: Add usb-phy support")
> Cc: [email protected]
>
> Signed-off-by: EJ Hsu <[email protected]>
> Signed-off-by: Haotien Hsu <[email protected]>
> ---
> drivers/phy/tegra/xusb.c | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c
> index 78045bd6c214..515298a9a433 100644
> --- a/drivers/phy/tegra/xusb.c
> +++ b/drivers/phy/tegra/xusb.c
> @@ -563,13 +563,6 @@ static int tegra_xusb_port_init(struct tegra_xusb_port *port,
>
> static void tegra_xusb_port_unregister(struct tegra_xusb_port *port)
> {
> - if (!IS_ERR_OR_NULL(port->usb_role_sw)) {
> - of_platform_depopulate(&port->dev);
> - usb_role_switch_unregister(port->usb_role_sw);
> - cancel_work_sync(&port->usb_phy_work);
> - usb_remove_phy(&port->usb_phy);
> - }
> -
> if (port->ops->remove)
> port->ops->remove(port);
>
> @@ -832,6 +825,14 @@ void tegra_xusb_usb2_port_remove(struct tegra_xusb_port *port)
> {
> struct tegra_xusb_usb2_port *usb2 = to_usb2_port(port);
>
> + if (!IS_ERR_OR_NULL(port->usb_role_sw)) {
> + of_platform_depopulate(&port->dev);
> + usb_role_switch_unregister(port->usb_role_sw);
> + cancel_work_sync(&port->usb_phy_work);
> + usb_remove_phy(&port->usb_phy);
> + port->usb_phy.dev->driver = NULL;
> + }
> +

It's a bit difficult to tell what exactly changed because of the
additional move. The move looks correct because this is only valid for
USB2 ports, but I think it'd be easier to review if the move was done
prior to the addition of the ->driver clearing. Or perhaps a mention in
the commit message would be nice.

It's obviously up to Vinod and Kishon if they want to see this
clarified. Either way is fine with me, so:

Acked-by: Thierry Reding <[email protected]>


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2023-05-08 09:12:33

by Vinod Koul

[permalink] [raw]
Subject: Re: [PATCH] phy: tegra: xusb: Fix use-after-free issue

On 04-05-23, 11:15, Thierry Reding wrote:
> On Thu, May 04, 2023 at 01:54:46PM +0800, Haotien Hsu wrote:
> > From: EJ Hsu <[email protected]>
> >
> > For the dual-role port, it will assign the phy dev to usb-phy dev and
> > use the port dev driver as the dev driver of usb-phy.
> >
> > When we try to destroy the port dev, it will destroy its dev driver
> > as well. But we did not remove the reference from usb-phy dev. This
> > might cause the use-after-free issue in KASAN.
> >
> > Fixes: e8f7d2f409a1 ("phy: tegra: xusb: Add usb-phy support")
> > Cc: [email protected]
> >
> > Signed-off-by: EJ Hsu <[email protected]>
> > Signed-off-by: Haotien Hsu <[email protected]>
> > ---
> > drivers/phy/tegra/xusb.c | 15 ++++++++-------
> > 1 file changed, 8 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c
> > index 78045bd6c214..515298a9a433 100644
> > --- a/drivers/phy/tegra/xusb.c
> > +++ b/drivers/phy/tegra/xusb.c
> > @@ -563,13 +563,6 @@ static int tegra_xusb_port_init(struct tegra_xusb_port *port,
> >
> > static void tegra_xusb_port_unregister(struct tegra_xusb_port *port)
> > {
> > - if (!IS_ERR_OR_NULL(port->usb_role_sw)) {
> > - of_platform_depopulate(&port->dev);
> > - usb_role_switch_unregister(port->usb_role_sw);
> > - cancel_work_sync(&port->usb_phy_work);
> > - usb_remove_phy(&port->usb_phy);
> > - }
> > -
> > if (port->ops->remove)
> > port->ops->remove(port);
> >
> > @@ -832,6 +825,14 @@ void tegra_xusb_usb2_port_remove(struct tegra_xusb_port *port)
> > {
> > struct tegra_xusb_usb2_port *usb2 = to_usb2_port(port);
> >
> > + if (!IS_ERR_OR_NULL(port->usb_role_sw)) {
> > + of_platform_depopulate(&port->dev);
> > + usb_role_switch_unregister(port->usb_role_sw);
> > + cancel_work_sync(&port->usb_phy_work);
> > + usb_remove_phy(&port->usb_phy);
> > + port->usb_phy.dev->driver = NULL;
> > + }
> > +
>
> It's a bit difficult to tell what exactly changed because of the
> additional move. The move looks correct because this is only valid for
> USB2 ports, but I think it'd be easier to review if the move was done
> prior to the addition of the ->driver clearing. Or perhaps a mention in
> the commit message would be nice.
>
> It's obviously up to Vinod and Kishon if they want to see this
> clarified. Either way is fine with me, so:

I agree changes need to be clarified, expecting updated v2 :-)

>
> Acked-by: Thierry Reding <[email protected]>



--
~Vinod