linux-kernel - Re: [v2 2/2] vfio iommu type1: fix the testing of capability for remote task

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Date:   Fri, 13 Jan 2017 12:22:05 +0530
From:   Kirti Wankhede <kwankhede@...dia.com>
To:     James Morris <jmorris@...ei.org>, Jike Song <jike.song@...el.com>
CC:     <alex.williamson@...hat.com>, <serge@...lyn.com>,
        <kraxel@...hat.com>, <linux-security-module@...r.kernel.org>,
        <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [v2 2/2] vfio iommu type1: fix the testing of capability for
 remote task

Looks good to me

Reviewed by: Kirti Wankhede <kwankhede@...dia.com>


On 1/13/2017 3:52 AM, James Morris wrote:
> On Thu, 12 Jan 2017, Jike Song wrote:
> 
>> Before the mdev enhancement type1 iommu used capable() to test the
>> capability of current task; in the course of mdev development a
>> new requirement, testing for another task other than current, was
>> raised.  ns_capable() was used for this purpose, however it still
>> tests current, the only difference is, in a specified namespace.
>>
>> Fix it by using has_capability() instead, which tests the cap for
>> specified task in init_user_ns, the same namespace as capable().
>>
>> Cc: Alex Williamson <alex.williamson@...hat.com>
>> Cc: Kirti Wankhede <kwankhede@...dia.com>
>> Cc: Gerd Hoffmann <kraxel@...hat.com>
>> Signed-off-by: Jike Song <jike.song@...el.com>
> 
> 
> Reviewed-by: James Morris <james.l.morris@...cle.com>
> 
>> ---
>>  drivers/vfio/vfio_iommu_type1.c | 3 +--
>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
>> index 9266271..77373e5 100644
>> --- a/drivers/vfio/vfio_iommu_type1.c
>> +++ b/drivers/vfio/vfio_iommu_type1.c
>> @@ -495,8 +495,7 @@ static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
>>  				  unsigned long *pfn_base, bool do_accounting)
>>  {
>>  	unsigned long limit;
>> -	bool lock_cap = ns_capable(task_active_pid_ns(dma->task)->user_ns,
>> -				   CAP_IPC_LOCK);
>> +	bool lock_cap = has_capability(dma->task, CAP_IPC_LOCK);
>>  	struct mm_struct *mm;
>>  	int ret;
>>  	bool rsvd;
>>
>