2019-01-11 14:19:28

by Camelia Alexandra Groza

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Subject: [PATCH net] net: phy: guard against accessing a NULL features bitmap

Since phy driver features became a link_mode bitmap, phy drivers that
don't have a list of features configured will cause the kernel to crash
when probed.

Fixes: 719655a14971 ("net: phy: Replace phy driver features u32 with link_mode bitmap")
Reported-by: Scott Wood <[email protected]>
Signed-off-by: Camelia Groza <[email protected]>
---
I'll submit a modified version of this patch to 4.20 stable once this
one is accepted.
---
drivers/net/phy/phy_device.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 5199000..ddf04ab 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -2154,7 +2154,8 @@ static int phy_probe(struct device *dev)
* a controller will attach, and may modify one
* or both of these values
*/
- linkmode_copy(phydev->supported, phydrv->features);
+ if (phydrv->features)
+ linkmode_copy(phydev->supported, phydrv->features);
of_set_phy_supported(phydev);
linkmode_copy(phydev->advertising, phydev->supported);

@@ -2174,8 +2175,9 @@ static int phy_probe(struct device *dev)
* (e.g. hardware erratum) where the driver wants to set only one
* of these bits.
*/
- if (test_bit(ETHTOOL_LINK_MODE_Pause_BIT, phydrv->features) ||
- test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, phydrv->features)) {
+ if (phydrv->features &&
+ (test_bit(ETHTOOL_LINK_MODE_Pause_BIT, phydrv->features) ||
+ test_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT, phydrv->features))) {
linkmode_clear_bit(ETHTOOL_LINK_MODE_Pause_BIT,
phydev->supported);
linkmode_clear_bit(ETHTOOL_LINK_MODE_Asym_Pause_BIT,
--
1.9.1



2019-01-11 14:22:17

by Andrew Lunn

[permalink] [raw]
Subject: Re: [PATCH net] net: phy: guard against accessing a NULL features bitmap

On Fri, Jan 11, 2019 at 01:56:46PM +0200, Camelia Groza wrote:
> Since phy driver features became a link_mode bitmap, phy drivers that
> don't have a list of features configured will cause the kernel to crash
> when probed.

Hi Camelia

A NULL features is a driver bug. So i would prefer to solve this
differently.

Please make phy_driver_register() do a WARN_ON(!new_driver->features)
and return -EINVAL.

Do you know of a specific driver which as a NULL value? We should fix
that as well.

Thank
Andrew

2019-01-11 14:23:45

by Camelia Alexandra Groza

[permalink] [raw]
Subject: RE: [PATCH net] net: phy: guard against accessing a NULL features bitmap

> -----Original Message-----
> From: Andrew Lunn <[email protected]>
> Sent: Friday, January 11, 2019 15:38
> To: Camelia Alexandra Groza <[email protected]>
> Cc: [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]
> Subject: Re: [PATCH net] net: phy: guard against accessing a NULL features
> bitmap
>
> On Fri, Jan 11, 2019 at 01:56:46PM +0200, Camelia Groza wrote:
> > Since phy driver features became a link_mode bitmap, phy drivers that
> > don't have a list of features configured will cause the kernel to crash
> > when probed.
>
> Hi Camelia
>
> A NULL features is a driver bug. So i would prefer to solve this
> differently.
>
> Please make phy_driver_register() do a WARN_ON(!new_driver->features)
> and return -EINVAL.

I wasn't aware that features are mandatory. I'll make the change.

> Do you know of a specific driver which as a NULL value? We should fix
> that as well.

Yes, there are five drivers that don't have features configured: BCM8706, BCM8727, CS4340, TN2020 and KSZ8873MLL.

I'm planning to send patches on net-next for the Cortina and Teranetics ones at least, but fixing the generic crash was my priority.

Thanks,
Camelia

2019-01-11 18:19:02

by Andrew Lunn

[permalink] [raw]
Subject: Re: [PATCH net] net: phy: guard against accessing a NULL features bitmap

> > Hi Camelia
> >
> > A NULL features is a driver bug. So i would prefer to solve this
> > differently.
> >
> > Please make phy_driver_register() do a WARN_ON(!new_driver->features)
> > and return -EINVAL.
>
> I wasn't aware that features are mandatory. I'll make the change.

It was not origionally, but really it should be now.

> Yes, there are five drivers that don't have features configured: BCM8706, BCM8727, CS4340, TN2020 and KSZ8873MLL.

> I'm planning to send patches on net-next for the Cortina and
> Teranetics ones at least, but fixing the generic crash was my
> priority.

O.K, will take the others.

Thanks
Andrew