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From: Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: "Gustavo A. R. Silva" <gustavo-L1vi/lXTdts+Va1GwOuvDg@public.gmane.org>
Cc: David Airlie <airlied-cv59FeDIM0c@public.gmane.org>,
	nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org,
	David Laight
	<David.Laight-ZS65k/vG3HxXrIkS9f7CXA@public.gmane.org>,
	Ben Skeggs <bskeggs-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH v2] drm/nouveau/secboot: remove VLA usage
Date: Wed, 14 Mar 2018 12:08:34 +0100	[thread overview]
Message-ID: <20180314110834.GB8564@ulmo> (raw)
In-Reply-To: <20180313162411.GA1983@embeddedgus>


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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-L1vi/lXTdts+Va1GwOuvDg@public.gmane.org>
> ---
> 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-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>

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WARNING: multiple messages have this Message-ID (diff)
From: Thierry Reding <thierry.reding@gmail.com>
To: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: David Laight <David.Laight@ACULAB.COM>,
	Ben Skeggs <bskeggs@redhat.com>, David Airlie <airlied@linux.ie>,
	dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] drm/nouveau/secboot: remove VLA usage
Date: Wed, 14 Mar 2018 12:08:34 +0100	[thread overview]
Message-ID: <20180314110834.GB8564@ulmo> (raw)
In-Reply-To: <20180313162411.GA1983@embeddedgus>

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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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  reply	other threads:[~2018-03-14 11:08 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-13 16:24 [PATCH v2] drm/nouveau/secboot: remove VLA usage Gustavo A. R. Silva
2018-03-14 11:08 ` Thierry Reding [this message]
2018-03-14 11:08   ` Thierry Reding
2018-03-16  2:05   ` Ben Skeggs
2018-03-16  2:05     ` Ben Skeggs
2018-04-26 23:25     ` Kees Cook
2018-05-23 22:48       ` Kees Cook
     [not found]         ` <CAGXu5jKAVxzftPJkY3YJ2P-M4bfk1+8UHZZYRG32qBxauTf43g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-05-24  0:36           ` Ben Skeggs
2018-05-24  0:36             ` Ben Skeggs
     [not found]             ` <CABDvA=mfOyx9X5JFvQaAYSQhvfaCZdqvVj7pD6=M0TX0AqQjcA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-05-24  0:47               ` Kees Cook
2018-05-24  0:47                 ` Kees Cook

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