Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.34 as permitted sender) client-ip=23.128.96.34;
Date:   Mon, 9 Oct 2023 14:10:01 -0700
From:   Kees Cook <keescook@chromium.org>
To:     "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc:     Chris Mason <clm@fb.com>, Josef Bacik <josef@toxicpanda.com>,
        David Sterba <dsterba@suse.com>, linux-btrfs@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH][next] btrfs: Add __counted_by for struct
 btrfs_delayed_item and use struct_size()
Message-ID: <202310091409.6F3B10C@keescook>
References: <ZSRmRj7leOsdUmJm@work>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ZSRmRj7leOsdUmJm@work>
Precedence: bulk

On Mon, Oct 09, 2023 at 02:44:54PM -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>

Looks right to me.

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

-- 
Kees Cook