Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Thu, 8 Apr 2021 15:59:53 -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>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>, 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,
        clang-built-linux@googlegroups.com
Subject: Re: [PATCH v6 00/18] Add support for Clang CFI
Message-ID: <202104081558.9A5FE3A@keescook>
References: <20210408182843.1754385-1-samitolvanen@google.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20210408182843.1754385-1-samitolvanen@google.com>
Precedence: bulk

On Thu, Apr 08, 2021 at 11:28:25AM -0700, Sami Tolvanen wrote:
> This series adds support for Clang's Control-Flow Integrity (CFI)
> checking. 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
> 
> The first patch contains build system changes and error handling,
> and implements support for cross-module indirect call checking. The
> remaining patches address issues caused by the compiler
> instrumentation. These include fixing known type mismatches, as well
> as issues with address space confusion and cross-module function
> address equality.
> 
> These patches add support only for arm64, but I'll post patches also
> for x86_64 after we address the remaining issues there, including
> objtool support.
> 
> You can also pull this series from
> 
>   https://github.com/samitolvanen/linux.git cfi-v6

This is working quite well for me and it looks like there are
good reviews. I'm going to toss it in linux-next unless anyone has
objections. I'm very excited to start using this. :)

-Kees

-- 
Kees Cook