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From:   Daniel Micay <danielmicay@gmail.com>
Date:   Fri, 7 Feb 2020 15:38:22 -0500
Message-ID: <CA+DvKQJ6jRHZeZteqY7q-9sU8v3xacSPj65uac3PQfst4cKiMA@mail.gmail.com>
Subject: Re: [PATCH 5/5] [RFC] mm: annotate memory allocation functions with
 their sizes
To:     Daniel Axtens <dja@axtens.net>
Cc:     Kernel Hardening <kernel-hardening@lists.openwall.com>,
        Linux-MM <linux-mm@kvack.org>, Kees Cook <keescook@chromium.org>,
        kernel list <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
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There are some uses of ksize in the kernel making use of the real
usable size of memory allocations rather than only the requested
amount. It's incorrect when mixed with alloc_size markers, since if a
number like 14 is passed that's used as the upper bound, rather than a
rounded size like 16 returned by ksize. It's unlikely to trigger any
issues with only CONFIG_FORTIFY_SOURCE, but it becomes more likely
with -fsanitize=object-size or other library-based usage of
__builtin_object_size.