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Date:   Fri, 4 Aug 2023 01:29:01 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Alexander Lobakin <aleksander.lobakin@intel.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Larysa Zaremba <larysa.zaremba@intel.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        netdev@vger.kernel.org, linux-hardening@vger.kernel.org,
        intel-wired-lan@lists.osuosl.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 2/3] virtchnl: fix fake 1-elem arrays in
 structures allocated as `nents + 1`
Message-ID: <202308040128.667940394B@keescook>
References: <20230728155207.10042-1-aleksander.lobakin@intel.com>
 <20230728155207.10042-3-aleksander.lobakin@intel.com>
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In-Reply-To: <20230728155207.10042-3-aleksander.lobakin@intel.com>
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On Fri, Jul 28, 2023 at 05:52:06PM +0200, Alexander Lobakin wrote:
> There are five virtchnl structures, which are allocated and checked in
> the code as `nents + 1`, meaning that they always have memory for one
> excessive element regardless of their actual number. This comes from
> that their sizeof() includes space for 1 element and then they get
> allocated via struct_size() or its open-coded equivalents, passing
> the actual number of elements.
> Expand virtchnl_struct_size() to handle such structures and replace
> those 1-elem arrays with proper flex ones. Also fix several places
> which open-code %IAVF_VIRTCHNL_VF_RESOURCE_SIZE. Finally, let the
> virtchnl_ether_addr_list size be computed automatically when there's
> no enough space for the whole list, otherwise we have to open-code
> reverse struct_size() logics.
> 
> Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>

I remain a fan of _Generic uses. :)

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook