From: Ard Biesheuvel <ardb@kernel.org>
To: Mark Brown <broonie@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Julien Thierry <jthierry@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Kees Cook <keescook@chromium.org>,
Michal Marek <michal.lkml@markovi.net>,
Mark Rutland <mark.rutland@arm.com>,
linux-efi <linux-efi@vger.kernel.org>,
linux-hardening@vger.kernel.org, live-patching@vger.kernel.org
Subject: Re: [RFC PATCH 00/17] objtool: add base support for arm64
Date: Fri, 22 Jan 2021 18:54:44 +0100 [thread overview]
Message-ID: <CAMj1kXF31FxCTbo4M8MX0aaegaq7AQXMUdCtsm6xrKUFSpkzjA@mail.gmail.com> (raw)
In-Reply-To: <20210122174342.GG6391@sirena.org.uk>
On Fri, 22 Jan 2021 at 18:44, Mark Brown <broonie@kernel.org> wrote:
>
> On Thu, Jan 21, 2021 at 12:54:52PM -0600, Josh Poimboeuf wrote:
>
> > 2) The shadow stack idea sounds promising -- how hard would it be to
> > make a prototype reliable unwinder?
>
> In theory it doesn't look too hard and I can't see a particular reason
> not to try doing this - there's going to be edge cases but hopefully for
> reliable stack trace they're all in areas where we would be happy to
> just decide the stack isn't reliable anyway, things like nesting which
> allocates separate shadow stacks for each nested level for example.
> I'll take a look.
This reminds me - a while ago, I had a stab at writing a rudimentary
GCC plugin that pushes/pops return addresses to a shadow call stack
pointed to by x18 [0]
I am by no means suggesting that we should rely on a GCC plugin for
this, only that it does seem rather straight-forward for the compiler
to manage a stack with return addresses like that (although the devil
is probably in the details, as usual)
[0] https://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git/log/?h=arm64-scs-gcc
next prev parent reply other threads:[~2021-01-22 18:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210120173800.1660730-1-jthierry@redhat.com>
[not found] ` <CAMj1kXHO0wgcZ4ZDxj1vS9s7Szfpz8Nz=SAW_=Dnnjy+S9AtyQ@mail.gmail.com>
[not found] ` <186bb660-6e70-6bbf-4e96-1894799c79ce@redhat.com>
[not found] ` <CAMj1kXHznGnN2UEai1c2UgyKuTFCS5SZ+qGR6VJwyCuccViw_A@mail.gmail.com>
[not found] ` <YAlkOFwkb6/hFm1Q@hirez.programming.kicks-ass.net>
[not found] ` <CAMj1kXE+675mbS66kteKHNfcrco84WTaEL6ncVkkV7tQgbMpFw@mail.gmail.com>
2021-01-21 18:54 ` [RFC PATCH 00/17] objtool: add base support for arm64 Josh Poimboeuf
2021-01-22 17:43 ` Mark Brown
2021-01-22 17:54 ` Ard Biesheuvel [this message]
2021-01-28 22:10 ` Madhavan T. Venkataraman
2021-01-22 21:15 ` Madhavan T. Venkataraman
2021-01-22 21:43 ` Ard Biesheuvel
2021-01-22 21:44 ` Madhavan T. Venkataraman
2021-01-25 21:19 ` Josh Poimboeuf
2021-01-22 21:16 ` Madhavan T. Venkataraman
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