Re: [RESEND] HID: steam: Prevent NULL pointer dereference in steam_{recv,send}_report

[Silvan Jegen]

Hi

Lee Jones <lee@xxxxxxxxxx> wrote:
> On Wed, 03 Aug 2022, Lee Jones wrote:
> 
> > It is possible for a malicious device to forgo submitting a Feature
> > Report.  The HID Steam driver presently makes no prevision for this
> > and de-references the 'struct hid_report' pointer obtained from the
> > HID devices without first checking its validity.  Let's change that.
> 
> This patch has been floating around since the beginning of July.
> 
> It fixes a real issue which was found by creating a virtual
> (software based) malicious device and registering it as a HID device.
> 
> There is nothing preventing a real attacker from creating a H/W
> version of the device in order to instigate an out-of-bounds read,
> potentially leading to a data leak.
> 
> Would someone be kind enough to review please?

AFACT this patch has been applied by Jiri on the 25th of August already.

Is a review still needed in this case?


Cheers,

Silvan

> 
> > Cc: Jiri Kosina <jikos@xxxxxxxxxx>
> > Cc: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
> > Cc: linux-input@xxxxxxxxxxxxxxx
> > Fixes: c164d6abf3841 ("HID: add driver for Valve Steam Controller")
> > Signed-off-by: Lee Jones <lee@xxxxxxxxxx>
> > ---
> >  drivers/hid/hid-steam.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> > 
> > diff --git a/drivers/hid/hid-steam.c b/drivers/hid/hid-steam.c
> > index a3b151b29bd71..fc616db4231bb 100644
> > --- a/drivers/hid/hid-steam.c
> > +++ b/drivers/hid/hid-steam.c
> > @@ -134,6 +134,11 @@ static int steam_recv_report(struct steam_device *steam,
> >  	int ret;
> >  
> >  	r = steam->hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0];
> > +	if (!r) {
> > +		hid_err(steam->hdev, "No HID_FEATURE_REPORT submitted -  nothing to read\n");
> > +		return -EINVAL;
> > +	}
> > +
> >  	if (hid_report_len(r) < 64)
> >  		return -EINVAL;
> >  
> > @@ -165,6 +170,11 @@ static int steam_send_report(struct steam_device *steam,
> >  	int ret;
> >  
> >  	r = steam->hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0];
> > +	if (!r) {
> > +		hid_err(steam->hdev, "No HID_FEATURE_REPORT submitted -  nothing to read\n");
> > +		return -EINVAL;
> > +	}
> > +
> >  	if (hid_report_len(r) < 64)
> >  		return -EINVAL;
> >