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Date:   Thu, 25 Mar 2021 21:35:24 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Sami Tolvanen <samitolvanen@google.com>
Cc:     Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Will Deacon <will@kernel.org>, Jessica Yu <jeyu@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Tejun Heo <tj@kernel.org>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Christoph Hellwig <hch@infradead.org>,
        Peter Zijlstra <peterz@infradead.org>, bpf@vger.kernel.org,
        linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org,
        linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 09/17] treewide: Change list_sort to use const pointers
Message-ID: <202103252135.9B17EFB@keescook>
References: <20210323203946.2159693-1-samitolvanen@google.com>
 <20210323203946.2159693-10-samitolvanen@google.com>
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On Tue, Mar 23, 2021 at 01:39:38PM -0700, Sami Tolvanen wrote:
> list_sort() internally casts the comparison function passed to it
> to a different type with constant struct list_head pointers, and
> uses this pointer to call the functions, which trips indirect call
> Control-Flow Integrity (CFI) checking.
> 
> Instead of removing the consts, this change defines the
> list_cmp_func_t type and changes the comparison function types of
> all list_sort() callers to use const pointers, thus avoiding type
> mismatches.
> 
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

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

-- 
Kees Cook