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Message-ID: <b14bc28d-c9e2-45fe-82b8-e77ffb4f7ecf@embeddedor.com>
Date:   Fri, 6 Oct 2023 22:47:15 +0200
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Subject: Re: [PATCH] drm/i915/guc: Annotate struct ct_incoming_msg with
 __counted_by
Content-Language: en-US
To:     Kees Cook <keescook@chromium.org>,
        Jani Nikula <jani.nikula@linux.intel.com>
Cc:     Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        John Harrison <John.C.Harrison@Intel.com>,
        Matthew Brost <matthew.brost@intel.com>,
        Michal Wajdeczko <michal.wajdeczko@intel.com>,
        Matt Roper <matthew.d.roper@intel.com>,
        intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-hardening@vger.kernel.org,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        Andi Shyti <andi.shyti@linux.intel.com>,
        Nirmoy Das <nirmoy.das@intel.com>,
        Jonathan Cavitt <jonathan.cavitt@intel.com>,
        Fei Yang <fei.yang@intel.com>, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev
References: <20231006201744.work.135-kees@kernel.org>
From:   "Gustavo A. R. Silva" <gustavo@embeddedor.com>
In-Reply-To: <20231006201744.work.135-kees@kernel.org>
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On 10/6/23 22:17, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct ct_incoming_msg.
> 
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
> Cc: John Harrison <John.C.Harrison@Intel.com>
> Cc: Matthew Brost <matthew.brost@intel.com>
> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
> Cc: Matt Roper <matthew.d.roper@intel.com>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-hardening@vger.kernel.org
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks!
-- 
Gustavo

> ---
>   drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> index 6e22af31513a..c33210ead1ef 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> @@ -96,7 +96,7 @@ struct ct_request {
>   struct ct_incoming_msg {
>   	struct list_head link;
>   	u32 size;
> -	u32 msg[];
> +	u32 msg[] __counted_by(size);
>   };
>   
>   enum { CTB_SEND = 0, CTB_RECV = 1 };