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* [PATCH v2] drm/nouveau/secboot: remove VLA usage
@ 2018-03-13 16:24 Gustavo A. R. Silva
  2018-03-14 11:08 ` Thierry Reding
  0 siblings, 1 reply; 7+ messages in thread
From: Gustavo A. R. Silva @ 2018-03-13 16:24 UTC (permalink / raw)
  To: David Laight, Ben Skeggs, David Airlie
  Cc: dri-devel, nouveau, linux-kernel, Gustavo A. R. Silva

In preparation to enabling -Wvla, remove VLA. In this particular
case directly use macro NVKM_MSGQUEUE_CMDLINE_SIZE instead of local
variable cmdline_size. Also, remove cmdline_size as it is not
actually useful anymore.

The use of stack Variable Length Arrays needs to be avoided, as they
can be a vector for stack exhaustion, which can be both a runtime bug
or a security flaw. Also, in general, as code evolves it is easy to
lose track of how big a VLA can get. Thus, we can end up having runtime
failures that are hard to debug.

Also, fixed as part of the directive to remove all VLAs from
the kernel: https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
Changes in v2:
 - Use sizeof(buf) instead of NVKM_MSGQUEUE_CMDLINE_SIZE. This change
   is based on the feedback provided by David Laight. Thanks David.

 drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c b/drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c
index 6f10b09..1e1f1c6 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c
@@ -80,12 +80,11 @@ acr_ls_msgqueue_post_run(struct nvkm_msgqueue *queue,
 			 struct nvkm_falcon *falcon, u32 addr_args)
 {
 	struct nvkm_device *device = falcon->owner->device;
-	u32 cmdline_size = NVKM_MSGQUEUE_CMDLINE_SIZE;
-	u8 buf[cmdline_size];
+	u8 buf[NVKM_MSGQUEUE_CMDLINE_SIZE];
 
-	memset(buf, 0, cmdline_size);
+	memset(buf, 0, sizeof(buf));
 	nvkm_msgqueue_write_cmdline(queue, buf);
-	nvkm_falcon_load_dmem(falcon, buf, addr_args, cmdline_size, 0);
+	nvkm_falcon_load_dmem(falcon, buf, addr_args, sizeof(buf), 0);
 	/* rearm the queue so it will wait for the init message */
 	nvkm_msgqueue_reinit(queue);
 
-- 
2.7.4

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH v2] drm/nouveau/secboot: remove VLA usage
  2018-03-13 16:24 [PATCH v2] drm/nouveau/secboot: remove VLA usage Gustavo A. R. Silva
@ 2018-03-14 11:08 ` Thierry Reding
  2018-03-16  2:05   ` Ben Skeggs
  0 siblings, 1 reply; 7+ messages in thread
From: Thierry Reding @ 2018-03-14 11:08 UTC (permalink / raw)
  To: Gustavo A. R. Silva
  Cc: David Laight, Ben Skeggs, David Airlie, dri-devel, nouveau, linux-kernel

[-- Attachment #1: Type: text/plain, Size: 1175 bytes --]

On Tue, Mar 13, 2018 at 11:24:11AM -0500, Gustavo A. R. Silva wrote:
> In preparation to enabling -Wvla, remove VLA. In this particular
> case directly use macro NVKM_MSGQUEUE_CMDLINE_SIZE instead of local
> variable cmdline_size. Also, remove cmdline_size as it is not
> actually useful anymore.
> 
> The use of stack Variable Length Arrays needs to be avoided, as they
> can be a vector for stack exhaustion, which can be both a runtime bug
> or a security flaw. Also, in general, as code evolves it is easy to
> lose track of how big a VLA can get. Thus, we can end up having runtime
> failures that are hard to debug.
> 
> Also, fixed as part of the directive to remove all VLAs from
> the kernel: https://lkml.org/lkml/2018/3/7/621
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
> Changes in v2:
>  - Use sizeof(buf) instead of NVKM_MSGQUEUE_CMDLINE_SIZE. This change
>    is based on the feedback provided by David Laight. Thanks David.
> 
>  drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)

Reviewed-by: Thierry Reding <treding@nvidia.com>

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^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH v2] drm/nouveau/secboot: remove VLA usage
  2018-03-14 11:08 ` Thierry Reding
@ 2018-03-16  2:05   ` Ben Skeggs
  2018-04-26 23:25     ` Kees Cook
  0 siblings, 1 reply; 7+ messages in thread
From: Ben Skeggs @ 2018-03-16  2:05 UTC (permalink / raw)
  To: Thierry Reding
  Cc: Gustavo A. R. Silva, David Airlie, nouveau, linux-kernel,
	dri-devel, David Laight, Ben Skeggs

On 14 March 2018 at 21:08, Thierry Reding <thierry.reding@gmail.com> wrote:
> On Tue, Mar 13, 2018 at 11:24:11AM -0500, Gustavo A. R. Silva wrote:
>> In preparation to enabling -Wvla, remove VLA. In this particular
>> case directly use macro NVKM_MSGQUEUE_CMDLINE_SIZE instead of local
>> variable cmdline_size. Also, remove cmdline_size as it is not
>> actually useful anymore.
>>
>> The use of stack Variable Length Arrays needs to be avoided, as they
>> can be a vector for stack exhaustion, which can be both a runtime bug
>> or a security flaw. Also, in general, as code evolves it is easy to
>> lose track of how big a VLA can get. Thus, we can end up having runtime
>> failures that are hard to debug.
>>
>> Also, fixed as part of the directive to remove all VLAs from
>> the kernel: https://lkml.org/lkml/2018/3/7/621
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>> ---
>> Changes in v2:
>>  - Use sizeof(buf) instead of NVKM_MSGQUEUE_CMDLINE_SIZE. This change
>>    is based on the feedback provided by David Laight. Thanks David.
>>
>>  drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c | 7 +++----
>>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> Reviewed-by: Thierry Reding <treding@nvidia.com>
Thanks everyone.  I've taken the patch in my tree.

Ben.

>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH v2] drm/nouveau/secboot: remove VLA usage
  2018-03-16  2:05   ` Ben Skeggs
@ 2018-04-26 23:25     ` Kees Cook
  2018-05-23 22:48       ` Kees Cook
  0 siblings, 1 reply; 7+ messages in thread
From: Kees Cook @ 2018-04-26 23:25 UTC (permalink / raw)
  To: Ben Skeggs
  Cc: Thierry Reding, Gustavo A. R. Silva, David Airlie, nouveau, LKML,
	Maling list - DRI developers, David Laight, Ben Skeggs

On Thu, Mar 15, 2018 at 7:05 PM, Ben Skeggs <skeggsb@gmail.com> wrote:
> On 14 March 2018 at 21:08, Thierry Reding <thierry.reding@gmail.com> wrote:
>> On Tue, Mar 13, 2018 at 11:24:11AM -0500, Gustavo A. R. Silva wrote:
>>> In preparation to enabling -Wvla, remove VLA. In this particular
>>> case directly use macro NVKM_MSGQUEUE_CMDLINE_SIZE instead of local
>>> variable cmdline_size. Also, remove cmdline_size as it is not
>>> actually useful anymore.
>>>
>>> The use of stack Variable Length Arrays needs to be avoided, as they
>>> can be a vector for stack exhaustion, which can be both a runtime bug
>>> or a security flaw. Also, in general, as code evolves it is easy to
>>> lose track of how big a VLA can get. Thus, we can end up having runtime
>>> failures that are hard to debug.
>>>
>>> Also, fixed as part of the directive to remove all VLAs from
>>> the kernel: https://lkml.org/lkml/2018/3/7/621
>>>
>>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>>> ---
>>> Changes in v2:
>>>  - Use sizeof(buf) instead of NVKM_MSGQUEUE_CMDLINE_SIZE. This change
>>>    is based on the feedback provided by David Laight. Thanks David.
>>>
>>>  drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c | 7 +++----
>>>  1 file changed, 3 insertions(+), 4 deletions(-)
>>
>> Reviewed-by: Thierry Reding <treding@nvidia.com>
> Thanks everyone.  I've taken the patch in my tree.

Hi!

Just checking in on this -- I don't see this patch in linux-next. Is
this queued somewhere else?

Thanks!

-Kees

-- 
Kees Cook
Pixel Security

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH v2] drm/nouveau/secboot: remove VLA usage
  2018-04-26 23:25     ` Kees Cook
@ 2018-05-23 22:48       ` Kees Cook
  2018-05-24  0:36         ` Ben Skeggs
  0 siblings, 1 reply; 7+ messages in thread
From: Kees Cook @ 2018-05-23 22:48 UTC (permalink / raw)
  To: Ben Skeggs, Daniel Vetter
  Cc: Thierry Reding, Gustavo A. R. Silva, David Airlie, nouveau, LKML,
	Maling list - DRI developers, David Laight, Ben Skeggs

On Thu, Apr 26, 2018 at 4:25 PM, Kees Cook <keescook@chromium.org> wrote:
> On Thu, Mar 15, 2018 at 7:05 PM, Ben Skeggs <skeggsb@gmail.com> wrote:
>> On 14 March 2018 at 21:08, Thierry Reding <thierry.reding@gmail.com> wrote:
>>> On Tue, Mar 13, 2018 at 11:24:11AM -0500, Gustavo A. R. Silva wrote:
>>>> In preparation to enabling -Wvla, remove VLA. In this particular
>>>> case directly use macro NVKM_MSGQUEUE_CMDLINE_SIZE instead of local
>>>> variable cmdline_size. Also, remove cmdline_size as it is not
>>>> actually useful anymore.
>>>>
>>>> The use of stack Variable Length Arrays needs to be avoided, as they
>>>> can be a vector for stack exhaustion, which can be both a runtime bug
>>>> or a security flaw. Also, in general, as code evolves it is easy to
>>>> lose track of how big a VLA can get. Thus, we can end up having runtime
>>>> failures that are hard to debug.
>>>>
>>>> Also, fixed as part of the directive to remove all VLAs from
>>>> the kernel: https://lkml.org/lkml/2018/3/7/621
>>>>
>>>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>>>> ---
>>>> Changes in v2:
>>>>  - Use sizeof(buf) instead of NVKM_MSGQUEUE_CMDLINE_SIZE. This change
>>>>    is based on the feedback provided by David Laight. Thanks David.
>>>>
>>>>  drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c | 7 +++----
>>>>  1 file changed, 3 insertions(+), 4 deletions(-)
>>>
>>> Reviewed-by: Thierry Reding <treding@nvidia.com>
>> Thanks everyone.  I've taken the patch in my tree.
>
> Hi!
>
> Just checking in on this -- I don't see this patch in linux-next. Is
> this queued somewhere else?

Hi, it's been another month; I still don't see this in linux-next.
Daniel, can this go via drm-misc?

-Kees

-- 
Kees Cook
Pixel Security

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH v2] drm/nouveau/secboot: remove VLA usage
  2018-05-23 22:48       ` Kees Cook
@ 2018-05-24  0:36         ` Ben Skeggs
  2018-05-24  0:47           ` Kees Cook
  0 siblings, 1 reply; 7+ messages in thread
From: Ben Skeggs @ 2018-05-24  0:36 UTC (permalink / raw)
  To: Kees Cook
  Cc: Ben Skeggs, Daniel Vetter, Thierry Reding, Gustavo A. R. Silva,
	David Airlie, nouveau, LKML, Maling list - DRI developers,
	David Laight

On Thu, May 24, 2018 at 8:48 AM, Kees Cook <keescook@chromium.org> wrote:
> On Thu, Apr 26, 2018 at 4:25 PM, Kees Cook <keescook@chromium.org> wrote:
>> On Thu, Mar 15, 2018 at 7:05 PM, Ben Skeggs <skeggsb@gmail.com> wrote:
>>> On 14 March 2018 at 21:08, Thierry Reding <thierry.reding@gmail.com> wrote:
>>>> On Tue, Mar 13, 2018 at 11:24:11AM -0500, Gustavo A. R. Silva wrote:
>>>>> In preparation to enabling -Wvla, remove VLA. In this particular
>>>>> case directly use macro NVKM_MSGQUEUE_CMDLINE_SIZE instead of local
>>>>> variable cmdline_size. Also, remove cmdline_size as it is not
>>>>> actually useful anymore.
>>>>>
>>>>> The use of stack Variable Length Arrays needs to be avoided, as they
>>>>> can be a vector for stack exhaustion, which can be both a runtime bug
>>>>> or a security flaw. Also, in general, as code evolves it is easy to
>>>>> lose track of how big a VLA can get. Thus, we can end up having runtime
>>>>> failures that are hard to debug.
>>>>>
>>>>> Also, fixed as part of the directive to remove all VLAs from
>>>>> the kernel: https://lkml.org/lkml/2018/3/7/621
>>>>>
>>>>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>>>>> ---
>>>>> Changes in v2:
>>>>>  - Use sizeof(buf) instead of NVKM_MSGQUEUE_CMDLINE_SIZE. This change
>>>>>    is based on the feedback provided by David Laight. Thanks David.
>>>>>
>>>>>  drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c | 7 +++----
>>>>>  1 file changed, 3 insertions(+), 4 deletions(-)
>>>>
>>>> Reviewed-by: Thierry Reding <treding@nvidia.com>
>>> Thanks everyone.  I've taken the patch in my tree.
>>
>> Hi!
>>
>> Just checking in on this -- I don't see this patch in linux-next. Is
>> this queued somewhere else?
>
> Hi, it's been another month; I still don't see this in linux-next.
> Daniel, can this go via drm-misc?
It's already queued in drm-next.

>
> -Kees
>
> --
> Kees Cook
> Pixel Security

^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH v2] drm/nouveau/secboot: remove VLA usage
  2018-05-24  0:36         ` Ben Skeggs
@ 2018-05-24  0:47           ` Kees Cook
  0 siblings, 0 replies; 7+ messages in thread
From: Kees Cook @ 2018-05-24  0:47 UTC (permalink / raw)
  To: Ben Skeggs
  Cc: Ben Skeggs, Daniel Vetter, Thierry Reding, Gustavo A. R. Silva,
	David Airlie, nouveau, LKML, Maling list - DRI developers,
	David Laight

On Wed, May 23, 2018 at 5:36 PM, Ben Skeggs <bskeggs@redhat.com> wrote:
> On Thu, May 24, 2018 at 8:48 AM, Kees Cook <keescook@chromium.org> wrote:
>> On Thu, Apr 26, 2018 at 4:25 PM, Kees Cook <keescook@chromium.org> wrote:
>>> On Thu, Mar 15, 2018 at 7:05 PM, Ben Skeggs <skeggsb@gmail.com> wrote:
>>>> On 14 March 2018 at 21:08, Thierry Reding <thierry.reding@gmail.com> wrote:
>>>>> On Tue, Mar 13, 2018 at 11:24:11AM -0500, Gustavo A. R. Silva wrote:
>>>>>> In preparation to enabling -Wvla, remove VLA. In this particular
>>>>>> case directly use macro NVKM_MSGQUEUE_CMDLINE_SIZE instead of local
>>>>>> variable cmdline_size. Also, remove cmdline_size as it is not
>>>>>> actually useful anymore.
>>>>>>
>>>>>> The use of stack Variable Length Arrays needs to be avoided, as they
>>>>>> can be a vector for stack exhaustion, which can be both a runtime bug
>>>>>> or a security flaw. Also, in general, as code evolves it is easy to
>>>>>> lose track of how big a VLA can get. Thus, we can end up having runtime
>>>>>> failures that are hard to debug.
>>>>>>
>>>>>> Also, fixed as part of the directive to remove all VLAs from
>>>>>> the kernel: https://lkml.org/lkml/2018/3/7/621
>>>>>>
>>>>>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>>>>>> ---
>>>>>> Changes in v2:
>>>>>>  - Use sizeof(buf) instead of NVKM_MSGQUEUE_CMDLINE_SIZE. This change
>>>>>>    is based on the feedback provided by David Laight. Thanks David.
>>>>>>
>>>>>>  drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c | 7 +++----
>>>>>>  1 file changed, 3 insertions(+), 4 deletions(-)
>>>>>
>>>>> Reviewed-by: Thierry Reding <treding@nvidia.com>
>>>> Thanks everyone.  I've taken the patch in my tree.
>>>
>>> Hi!
>>>
>>> Just checking in on this -- I don't see this patch in linux-next. Is
>>> this queued somewhere else?
>>
>> Hi, it's been another month; I still don't see this in linux-next.
>> Daniel, can this go via drm-misc?
> It's already queued in drm-next.

Ah-ha, great, thanks! Looks like I just got unlucky with linux-next
pausing on the 17th and this getting committed on the 18th. :) But,
yes, I see it now:
https://cgit.freedesktop.org/drm/drm/commit/drivers/gpu/drm/nouveau/nvkm/subdev/secboot/ls_ucode_msgqueue.c?id=7bf5b70befd7817b9e42acbd2291b2042ea1bf81

-Kees

-- 
Kees Cook
Pixel Security

^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2018-05-24  0:47 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-03-13 16:24 [PATCH v2] drm/nouveau/secboot: remove VLA usage Gustavo A. R. Silva
2018-03-14 11:08 ` Thierry Reding
2018-03-16  2:05   ` Ben Skeggs
2018-04-26 23:25     ` Kees Cook
2018-05-23 22:48       ` Kees Cook
2018-05-24  0:36         ` Ben Skeggs
2018-05-24  0:47           ` Kees Cook

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