On Wed, Apr 20, 2016 at 9:26 AM, Christian König
<deathsimple@xxxxxxxxxxx> 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@xxxxxxx>
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@xxxxxxxxxx>
>> Cc: <stable@xxxxxxxxxxxxxxx>
>> ---
>> 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);
>> }
>>
>
>
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