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Subject: Re: [PATCH] platform/loongarch: laptop: fix possible UAF in
 generic_acpi_laptop_init()
To:     Huacai Chen <chenhuacai@kernel.org>
CC:     <linux-kernel@vger.kernel.org>, <lvjianmin@loongson.cn>,
        <chenhuacai@loongson.cn>
References: <20221013131209.775969-1-yangyingliang@huawei.com>
 <CAAhV-H48bH5VAYhsMvupUSWouAUR=s9b4hJYdJYdymCYbKQfjA@mail.gmail.com>
From:   Yang Yingliang <yangyingliang@huawei.com>
Message-ID: <b2dcb989-4bda-8921-a5a0-7ea29d6382ad@huawei.com>
Date:   Fri, 14 Oct 2022 09:23:03 +0800
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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.

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
>>
> .