Re: [Intel-gfx] [PATCH] drm/i915: Validate execbuffer start/length arguments against the target bo

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 28 Apr 2016, Jani Nikula <jani.nikula@linux.intel.com> wrote:
> On Fri, 20 Nov 2015, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote:
>> On Fri, Nov 20, 2015 at 03:11:04PM +0000, Chris Wilson wrote:
>>> The offset within and the length of the command sequence to execute are
>>> supplied by the user with respect to the batch buffer. We should be
>>> validating that region is wholly contained within the batch buffer;
>>> make it so.
>>> 
>>> Reported-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
>>> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>>> Cc: stable@vger.kernel.org
>>> ---
>>>  drivers/gpu/drm/i915/i915_gem_execbuffer.c | 7 +++++++
>>>  1 file changed, 7 insertions(+)
>>> 
>>> diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
>>> index a4c243cec4aa..e38284c1b89f 100644
>>> --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
>>> +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
>>> @@ -1462,6 +1462,13 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
>>>  	/* take note of the batch buffer before we might reorder the lists */
>>>  	batch_obj = eb_get_batch(eb);
>>>  
>>> +	if (args->batch_len > batch_obj->base.size ||
>>> +	    args->batch_start_offset > batch_obj->base.size - args->batch_len) {
>>
>> lgtm. No possibility of overflow doing it that way.
>>
>> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

I don't know what I fat fingered with the previous mail, but I just
stumbled upon this patch and noticed it never made it. Is this still
valid?

BR,
Jani.


>>
>>> +		DRM_DEBUG("Attempting to execute commands from beyond the bounds of the batch object\n");
>>> +		ret = -EINVAL;
>>> +		goto err;
>>> +	}
>>> +
>>>  	/* Move the objects en-masse into the GTT, evicting if necessary. */
>>>  	need_relocs = (args->flags & I915_EXEC_NO_RELOC) == 0;
>>>  	ret = i915_gem_execbuffer_reserve(ring, &eb->vmas, ctx, &need_relocs);
>>> -- 
>>> 2.6.2
>>> 
>>> _______________________________________________
>>> Intel-gfx mailing list
>>> Intel-gfx@lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Technology Center