ACK/cmnt: [X][E][CVE-2020-11608][SRU][PATCH 1/1] media: ov519: add missing endpoint sanity checks

[Kleber Souza]

On 16.04.20 10:50, Po-Hsu Lin wrote:
> From: Johan Hovold <johan at kernel.org>
> 
> CVE-2020-11608
> 
> Make sure to check that we have at least one endpoint before accessing
> the endpoint array to avoid dereferencing a NULL-pointer on stream
> start.
> 
> Note that these sanity checks are not redundant as the driver is mixing
> looking up altsettings by index and by number, which need not coincide.
> 
> Fixes: 1876bb923c98 ("V4L/DVB (12079): gspca_ov519: add support for the ov511 bridge")
> Fixes: b282d87332f5 ("V4L/DVB (12080): gspca_ov519: Fix ov518+ with OV7620AE (Trust spacecam 320)")
> Cc: stable <stable at vger.kernel.org>     # 2.6.31
> Cc: Hans de Goede <hdegoede at redhat.com>
> Signed-off-by: Johan Hovold <johan at kernel.org>
> Signed-off-by: Hans Verkuil <hverkuil-cisco at xs4all.nl>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei at kernel.org>
> (cherry picked from commit 998912346c0da53a6dbb71fab3a138586b596b30)
> Signed-off-by: Po-Hsu Lin <po-hsu.lin at canonical.com>

LGTM.

Acked-by: Kleber Sacilotto de Souza <kleber.souza at canonical.com>


The CVE matrix says this fix is needed for Xenial as well. Does it apply cleanly on X or
does it need to be backported for it?

> ---
>  drivers/media/usb/gspca/ov519.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/media/usb/gspca/ov519.c b/drivers/media/usb/gspca/ov519.c
> index c7aafdb..9a49b50 100644
> --- a/drivers/media/usb/gspca/ov519.c
> +++ b/drivers/media/usb/gspca/ov519.c
> @@ -3507,6 +3507,11 @@ static void ov511_mode_init_regs(struct sd *sd)
>  		return;
>  	}
>  
> +	if (alt->desc.bNumEndpoints < 1) {
> +		sd->gspca_dev.usb_err = -ENODEV;
> +		return;
> +	}
> +
>  	packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize);
>  	reg_w(sd, R51x_FIFO_PSIZE, packet_size >> 5);
>  
> @@ -3632,6 +3637,11 @@ static void ov518_mode_init_regs(struct sd *sd)
>  		return;
>  	}
>  
> +	if (alt->desc.bNumEndpoints < 1) {
> +		sd->gspca_dev.usb_err = -ENODEV;
> +		return;
> +	}
> +
>  	packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize);
>  	ov518_reg_w32(sd, R51x_FIFO_PSIZE, packet_size & ~7, 2);
>  
>