Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20220513202159.1550547-1-samitolvanen@google.com>
 <20220513202159.1550547-11-samitolvanen@google.com> <202205141451.AABEE8B@keescook>
In-Reply-To: <202205141451.AABEE8B@keescook>
From:   Sami Tolvanen <samitolvanen@google.com>
Date:   Mon, 16 May 2022 09:24:50 -0700
Message-ID: <CABCJKufbTGxjYg=vLwDUtxb06yues+yH9wV3J2hVa8uM+u1bvQ@mail.gmail.com>
Subject: Re: [RFC PATCH v2 10/21] arm64: Add CFI error handling
To:     Kees Cook <keescook@chromium.org>
Cc:     linux-kernel@vger.kernel.org, Josh Poimboeuf <jpoimboe@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>, x86@kernel.org,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Joao Moreira <joao@overdrivepizza.com>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        linux-hardening@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, llvm@lists.linux.dev
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Sat, May 14, 2022 at 2:51 PM Kees Cook <keescook@chromium.org> wrote:
>
> On Fri, May 13, 2022 at 01:21:48PM -0700, Sami Tolvanen wrote:
> > With -fsanitize=kcfi, CFI always traps. Add arm64 support for handling
> > CFI failures. The registers containing the target address and the
> > expected type are encoded in the first ten bits of the ESR as follows:
> >
> >  - 0-4: n, where the register Xn contains the target address
> >  - 5-9: m, where the register Wm contains the type hash
> >
> > Suggested-by: Mark Rutland <mark.rutland@arm.com>
> > Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
>
> It might be nice just to include an example exception Oops in this
> commit log.

Agreed, I'll add an example.

Sami