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From:   "Gomonovych, Vasyl" <gomonovych@gmail.com>
Date:   Wed, 22 Nov 2017 21:46:14 +0100
Message-ID: <CAHYXAnL6YPZex7AV5fO1NUtfM7hQtDZCS2DZMjJtFf3A8BBw6A@mail.gmail.com>
Subject: Re: [PATCH] VMCI: Use memdup_user() as a cleanup
To:     Joe Perches <joe@perches.com>
Cc:     linux-kernel@vger.kernel.org
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I am agree, I will change it.

On Wed, Nov 22, 2017 at 4:55 PM, Joe Perches <joe@perches.com> wrote:
> On Wed, 2017-11-22 at 16:29 +0100, Vasyl Gomonovych wrote:
>> Fix coccicheck warning which recommends to use memdup_user():
>> drivers/misc/vmw_vmci/vmci_host.c:757:11-18: WARNING opportunity for mem=
dup_user
>> Generated by: scripts/coccinelle/memdup_user/memdup_user.cocci
>
> Nice little cleanup.
>
>> diff --git a/drivers/misc/vmw_vmci/vmci_host.c b/drivers/misc/vmw_vmci/v=
mci_host.c
> []
>> @@ -754,18 +754,12 @@ static int vmci_host_do_ctx_set_cpt_state(struct v=
mci_host_dev *vmci_host_dev,
> []
>> +     cpt_buf =3D memdup_user((void __user *)(uintptr_t)set_info.cpt_buf=
,
>> +                     set_info.buf_size);
>> +     if (IS_ERR(cpt_buf)) {
>> +             vmci_ioctl_err("cannot allocate memory to set cpt state (t=
ype=3D%d)\n",
>> +                             set_info.cpt_type);
>> +             return PTR_ERR(cpt_buf);
>
> Trivia:
>
> The vmci_ioctl_err might not be necessary.
> There is a dump_stack() on allocation failure.
>
> and
>
>> @@ -774,7 +768,6 @@ static int vmci_host_do_ctx_set_cpt_state(struct vmc=
i_host_dev *vmci_host_dev,
>>
>>       retval =3D copy_to_user(uptr, &set_info, sizeof(set_info)) ? -EFAU=
LT : 0;
>>
>> -out:
>>       kfree(cpt_buf);
>>       return retval;
>
> Perhaps move the kfree above the copy_to_user,
> remove the retval declaration and use
>
>         return copy_to_user(uptr, &set_info, sizeof(set_info)) ? -EFAULT =
: 0;
>


--=20
=D0=94=D0=BE=D0=B1=D1=80=D0=BE=D1=97 =D0=B2=D0=B0=D0=BC =D0=BF=D0=BE=D1=80=
=D0=B8 =D0=B4=D0=BD=D1=8F.

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