Received-SPF: pass (google.com: domain of linux-kernel+bounces-111384-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223;
Precedence: bulk
MIME-Version: 1.0
References: <20240322090209.13384-1-brgl@bgdev.pl> <20240322111835.GA24228@rigel>
In-Reply-To: <20240322111835.GA24228@rigel>
From: Bartosz Golaszewski <brgl@bgdev.pl>
Date: Fri, 22 Mar 2024 12:52:29 +0100
Message-ID: <CAMRc=Md87eGmjehSEegdFCdv6D3H1p2On153JowY5cDnW9iw8Q@mail.gmail.com>
Subject: Re: [PATCH v2] gpio: cdev: sanitize the label before requesting the interrupt
To: Kent Gibson <warthog618@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>, linux-gpio@vger.kernel.org, 
	linux-kernel@vger.kernel.org, Alexey Dobriyan <adobriyan@gmail.com>, stable@vger.kernel.org, 
	Stefan Wahren <wahrenst@gmx.net>, Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

On Fri, Mar 22, 2024 at 12:18=E2=80=AFPM Kent Gibson <warthog618@gmail.com>=
 wrote:
>
> On Fri, Mar 22, 2024 at 10:02:08AM +0100, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > @@ -2198,12 +2216,18 @@ static int lineevent_create(struct gpio_device =
*gdev, void __user *ip)
> >       if (ret)
> >               goto out_free_le;
> >
> > +     label =3D make_irq_label(le->label);
> > +     if (!label) {
> > +             ret =3D -ENOMEM;
> > +             goto out_free_le;
> > +     }
> > +
> >       /* Request a thread to read the events */
> >       ret =3D request_threaded_irq(irq,
> >                                  lineevent_irq_handler,
> >                                  lineevent_irq_thread,
> >                                  irqflags,
> > -                                le->label,
> > +                                label,
> >                                  le);
> >       if (ret)
> >               goto out_free_le;
>
> Leaks label if the request_threaded_irq() fails.
>

Ah, dammit, I didn't catch the fact that irq_free() will not return
the label address if the request failed.

Nice catch.

Bart