[PATCH 1/2] drm/radeon: forbid mapping of userptr bo through radeon device file

[Alex Deucher]

On Wed, Apr 20, 2016 at 9:26 AM, Christian König
<deathsimple at vodafone.de> wrote:
> There are also checks in (amdgpu|radeon)_gem_mmap_ioctl() to prevent this as
> well.
>
> But it shouldn't hurt us to check that here as well. So both patches are
> Reviewed-by: Christian König <christian.koenig at amd.com>

Applied both.  Thanks!

Alex

>
> Regards,
> Christian.
>
> Am 19.04.2016 um 15:07 schrieb Jérôme Glisse:
>>
>> Allowing userptr bo which are basicly a list of page from some vma
>> (so either anonymous page or file backed page) would lead to serious
>> corruption of kernel structures and counters (because we overwrite
>> the page->mapping field when mapping buffer).
>>
>> This will already block if the buffer was populated before anyone does
>> try to mmap it because then TTM_PAGE_FLAG_SG would be set in in the
>> ttm_tt flags. But that flag is check before ttm_tt_populate in the ttm
>> vm fault handler.
>>
>> So to be safe just add a check to verify_access() callback.
>>
>> Signed-off-by: Jérôme Glisse <jglisse at redhat.com>
>> Cc: <stable at vger.kernel.org>
>> ---
>>   drivers/gpu/drm/radeon/radeon_ttm.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c
>> b/drivers/gpu/drm/radeon/radeon_ttm.c
>> index 7dddfdc..90f7394 100644
>> --- a/drivers/gpu/drm/radeon/radeon_ttm.c
>> +++ b/drivers/gpu/drm/radeon/radeon_ttm.c
>> @@ -235,6 +235,8 @@ static int radeon_verify_access(struct
>> ttm_buffer_object *bo, struct file *filp)
>>   {
>>         struct radeon_bo *rbo = container_of(bo, struct radeon_bo, tbo);
>>   +     if (radeon_ttm_tt_has_userptr(bo->ttm))
>> +               return -EPERM;
>>         return drm_vma_node_verify_access(&rbo->gem_base.vma_node, filp);
>>   }
>>
>
>
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel