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Date:   Tue, 19 Oct 2021 10:06:32 +0000
To:     Sami Tolvanen <samitolvanen@google.com>
From:   Alexander Lobakin <alobakin@pm.me>
Cc:     Alexander Lobakin <alobakin@pm.me>, x86@kernel.org,
        Kees Cook <keescook@chromium.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
        llvm@lists.linux.dev
Reply-To: Alexander Lobakin <alobakin@pm.me>
Subject: Re: [PATCH v5 00/15] x86: Add support for Clang CFI
Message-ID: <20211019095947.89257-1-alobakin@pm.me>
In-Reply-To: <20211013181658.1020262-1-samitolvanen@google.com>
References: <20211013181658.1020262-1-samitolvanen@google.com>
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From: Sami Tolvanen <samitolvanen@google.com>
Date: Wed, 13 Oct 2021 11:16:43 -0700

> This series adds support for Clang's Control-Flow Integrity (CFI)
> checking to x86_64. With CFI, the compiler injects a runtime
> check before each indirect function call to ensure the target is
> a valid function with the correct static type. This restricts
> possible call targets and makes it more difficult for an attacker
> to exploit bugs that allow the modification of stored function
> pointers. For more details, see:
>
>   https://clang.llvm.org/docs/ControlFlowIntegrity.html
>
> Note that v5 is based on tip/master. The first two patches contain
> objtool support for CFI, the remaining patches change function
> declarations to use opaque types, fix type mismatch issues that
> confuse the compiler, and disable CFI where it can't be used.
>
> You can also pull this series from
>
>   https://github.com/samitolvanen/linux.git x86-cfi-v5

Hi,

I found [0] while was testing Peter's retpoline series, wanted to
ask / double check if that is because I'm using ClangCFI for x86
on unsupported Clang 12. It is fixed in 13 I suppose?

[0] https://lore.kernel.org/all/20211019094038.80569-1-alobakin@pm.me

Thanks,
Al