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Date:   Tue, 29 Jun 2021 16:24:00 +0200
From:   Heiko Carstens <hca@linux.ibm.com>
To:     Kees Cook <keescook@chromium.org>
Cc:     Stefan Haberland <sth@linux.ibm.com>,
        Jan Hoeppner <hoeppner@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
        linux-hardening@vger.kernel.org
Subject: Re: [PATCH] s390/dasd: Avoid field over-reading memcpy()
Message-ID: <YNstANuJWSprSefl@osiris>
References: <20210616201917.1246079-1-keescook@chromium.org>
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In-Reply-To: <20210616201917.1246079-1-keescook@chromium.org>
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On Wed, Jun 16, 2021 at 01:19:17PM -0700, Kees Cook wrote:
> In preparation for FORTIFY_SOURCE performing compile-time and run-time
> field array bounds checking for memcpy(), memmove(), and memset(),
> avoid intentionally reading across neighboring array fields.
> 
> Add a wrapping structure to serve as the memcpy() source, so the compiler
> can do appropriate bounds checking, avoiding this future warning:
> 
> In function '__fortify_memcpy',
>     inlined from 'create_uid' at drivers/s390/block/dasd_eckd.c:749:2:
> ./include/linux/fortify-string.h:246:4: error: call to '__read_overflow2_field' declared with attribute error: detected read beyond size of field (2nd parameter)
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  drivers/s390/block/dasd_eckd.c | 2 +-
>  drivers/s390/block/dasd_eckd.h | 6 ++++--
>  2 files changed, 5 insertions(+), 3 deletions(-)

I'll leave it up to Stefan Haberland and Jan Hoeppner to handle this one.