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From:   Sami Tolvanen <samitolvanen@google.com>
Date:   Fri, 14 Oct 2022 11:34:30 -0700
Message-ID: <CABCJKuca0fOAs=E6LeHJiT2LOXEoPvLVKztA=u+ARcw=tbT=tw@mail.gmail.com>
Subject: Re: [PATCH v10 25/27] x86: enable initial Rust support
To:     Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Miguel Ojeda <ojeda@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, patches@lists.linux.dev,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@google.com>,
        David Gow <davidgow@google.com>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>, x86@kernel.org,
        "H. Peter Anvin" <hpa@zytor.com>, linux-doc@vger.kernel.org
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On Fri, Oct 14, 2022 at 11:05 AM Miguel Ojeda
<miguel.ojeda.sandonis@gmail.com> wrote:
>
> On Tue, Oct 11, 2022 at 1:16 AM Sami Tolvanen <samitolvanen@google.com> wrote:
> >
> > Rust supports IBT with -Z cf-protection=branch, but I don't see this
> > option being enabled in the kernel yet. Cross-language CFI is going to
> > require a lot more work though because the type systems are not quite
> > compatible:
> >
> > https://github.com/rust-lang/rfcs/pull/3296
>
> I have pinged Ramon de C Valle as he is the author of the RFC above
> and implementation work too; since a month or so ago he also leads the
> Exploit Mitigations Project Group in Rust.

Thanks, Miguel. I also talked to Ramon about KCFI earlier this week
and he expressed interest in helping with rustc support for it. In the
meanwhile, I think we can just add a depends on !CFI_CLANG to avoid
issues here.

Sami