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SubjectRe: [PATCH] isdn/gigaset: check endpoint null in gigaset_probe
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Phong Tran schreef op vr 26-07-2019 om 20:35 [+0700]:
> This fixed the potential reference NULL pointer while using variable
> endpoint.
>
> Reported-by: syzbot+35b1c403a14f5c89eba7@syzkaller.appspotmail.com
> Tested by syzbot:
> https://groups.google.com/d/msg/syzkaller-bugs/wnHG8eRNWEA/Qn2HhjNdBgAJ
>
> Signed-off-by: Phong Tran <tranmanphong@gmail.com>
> ---
> drivers/isdn/gigaset/usb-gigaset.c | 9 +++++++++

This is now drivers/staging/isdn/gigaset/usb-gigaset.c.

> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/isdn/gigaset/usb-gigaset.c b/drivers/isdn/gigaset/usb-gigaset.c
> index 1b9b43659bdf..2e011f3db59e 100644
> --- a/drivers/isdn/gigaset/usb-gigaset.c
> +++ b/drivers/isdn/gigaset/usb-gigaset.c
> @@ -703,6 +703,10 @@ static int gigaset_probe(struct usb_interface *interface,
> usb_set_intfdata(interface, cs);
>
> endpoint = &hostif->endpoint[0].desc;
> + if (!endpoint) {
> + dev_err(cs->dev, "Couldn't get control endpoint\n");
> + return -ENODEV;
> + }

When can this happen? Is this one of those bugs that one can only trigger with
a specially crafted (evil) usb device?

> buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
> ucs->bulk_out_size = buffer_size;
> @@ -722,6 +726,11 @@ static int gigaset_probe(struct usb_interface *interface,
> }
>
> endpoint = &hostif->endpoint[1].desc;
> + if (!endpoint) {
> + dev_err(cs->dev, "Endpoint not available\n");
> + retval = -ENODEV;
> + goto error;
> + }
>
> ucs->busy = 0;
>

Please note that I'm very close to getting cut off from the ISDN network, so
the chances of being able to testi this on a live system are getting small.

Thanks,


Paul Bolle

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