Re: [PATCH] VMCI: Use memdup_user() as a cleanup

[Gomonovych, Vasyl]

I am agree, I will change it.

On Wed, Nov 22, 2017 at 4:55 PM, Joe Perches <joe@xxxxxxxxxxx> 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 memdup_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/vmci_host.c
> []
>> @@ -754,18 +754,12 @@ static int vmci_host_do_ctx_set_cpt_state(struct vmci_host_dev *vmci_host_dev,
> []
>> +     cpt_buf = 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 (type=%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 vmci_host_dev *vmci_host_dev,
>>
>>       retval = copy_to_user(uptr, &set_info, sizeof(set_info)) ? -EFAULT : 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;
>



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