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Date:   Mon, 9 Oct 2023 15:04:44 -0700
From:   Kees Cook <keescook@chromium.org>
To:     "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Banajit Goswami <bgoswami@quicinc.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        alsa-devel@alsa-project.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH][next] soc: qcom: apr: Add __counted_by for struct
 apr_rx_buf and use struct_size()
Message-ID: <202310091504.0C46189372@keescook>
References: <ZSRw6RNi3Crhd32H@work>
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On Mon, Oct 09, 2023 at 03:30:17PM -0600, Gustavo A. R. Silva 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).
> 
> While there, use struct_size() helper, instead of the open-coded
> version, to calculate the size for the allocation of the whole
> flexible structure, including of course, the flexible-array member.
> 
> This code was found with the help of Coccinelle, and audited and
> fixed manually.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Yup, looks right.

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

-- 
Kees Cook