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References: <20221014015212.1150629-1-yangyingliang@huawei.com>
In-Reply-To: <20221014015212.1150629-1-yangyingliang@huawei.com>
From:   Huacai Chen <chenhuacai@kernel.org>
Date:   Fri, 14 Oct 2022 09:56:34 +0800
Message-ID: <CAAhV-H6nGcVKn9E8hvcFh1=3Ak04xg4Xe3+oXM6yJao+M7DvyA@mail.gmail.com>
Subject: Re: [PATCH] platform/loongarch: laptop: fix possible UAF and simplify
 return 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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Queued for loongarch-fixes, thanks.

Huacai

On Fri, Oct 14, 2022 at 9:52 AM 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.
>
> The error code in generic_subdriver_init() is always negative,
> the return of generic_subdriver_init() can be simplified.
>
> Fixes: 6246ed09111f ("LoongArch: Add ACPI-based generic laptop driver")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
>  drivers/platform/loongarch/loongson-laptop.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/platform/loongarch/loongson-laptop.c b/drivers/platform/loongarch/loongson-laptop.c
> index f0166ad5d2c2..572290abf151 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);
> @@ -519,7 +523,7 @@ static int __init generic_subdriver_init(struct generic_sub_driver *sub_driver)
>
>  err_out:
>         generic_subdriver_exit(sub_driver);
> -       return (ret < 0) ? ret : 0;
> +       return ret;
>  }
>
>  static void generic_subdriver_exit(struct generic_sub_driver *sub_driver)
> --
> 2.25.1
>