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From:   Huacai Chen <chenhuacai@kernel.org>
Date:   Fri, 14 Oct 2022 09:32:46 +0800
Message-ID: <CAAhV-H7WwKyUUyPMsYQ0u3QNWVRo3hvUt30qXJ+e5rpE7Giotw@mail.gmail.com>
Subject: Re: [PATCH] platform/loongarch: laptop: fix possible UAF in generic_acpi_laptop_init()
To:     Yang Yingliang <yangyingliang@huawei.com>
Cc:     linux-kernel@vger.kernel.org, lvjianmin@loongson.cn,
        chenhuacai@loongson.cn
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On Fri, Oct 14, 2022 at 9:23 AM Yang Yingliang <yangyingliang@huawei.com> wrote:
>
> Hi, Huacai
>
> On 2022/10/13 23:47, Huacai Chen wrote:
> > Hi, Yingliang,
> >
> > Thank you for your patches, but could you please merge the two trivial
> > patches to a single one?
> It's OK to merge them into a single one in v2.
> But the two patches solved different things, they are not relative.
You can title it with "Simplify and improve generic_subdriver_init()" or so.

Huacai
>
> Thanks,
> Yang
> >
> > Huacai
> >
> > On Thu, Oct 13, 2022 at 9:12 PM Yang Yingliang <yangyingliang@huawei.com> wrote:
> >> Current the return value of 'sub_driver->init' is not checked,
> >> if sparse_keymap_setup() called in the init function fails,
> >> 'generic_inputdev' is freed, then it willl lead a UAF when
> >> using it in generic_acpi_laptop_init(). Fix it by checking
> >> return value. Set generic_inputdev to NULL after free to avoid
> >> double free it.
> >>
> >> Fixes: 6246ed09111f ("LoongArch: Add ACPI-based generic laptop driver")
> >> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> >> ---
> >>   drivers/platform/loongarch/loongson-laptop.c | 8 ++++++--
> >>   1 file changed, 6 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/platform/loongarch/loongson-laptop.c b/drivers/platform/loongarch/loongson-laptop.c
> >> index f0166ad5d2c2..a665fd1042ac 100644
> >> --- a/drivers/platform/loongarch/loongson-laptop.c
> >> +++ b/drivers/platform/loongarch/loongson-laptop.c
> >> @@ -448,6 +448,7 @@ static int __init event_init(struct generic_sub_driver *sub_driver)
> >>          if (ret < 0) {
> >>                  pr_err("Failed to setup input device keymap\n");
> >>                  input_free_device(generic_inputdev);
> >> +               generic_inputdev = NULL;
> >>
> >>                  return ret;
> >>          }
> >> @@ -502,8 +503,11 @@ static int __init generic_subdriver_init(struct generic_sub_driver *sub_driver)
> >>          if (ret)
> >>                  return -EINVAL;
> >>
> >> -       if (sub_driver->init)
> >> -               sub_driver->init(sub_driver);
> >> +       if (sub_driver->init) {
> >> +               ret = sub_driver->init(sub_driver);
> >> +               if (ret)
> >> +                       goto err_out;
> >> +       }
> >>
> >>          if (sub_driver->notify) {
> >>                  ret = setup_acpi_notify(sub_driver);
> >> --
> >> 2.25.1
> >>
> > .