From: Will Deacon <will@kernel.org>
To: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Elena Reshetova <elena.reshetova@intel.com>,
x86@kernel.org, Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Potapenko <glider@google.com>,
Alexander Popov <alex.popov@linux.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Jann Horn <jannh@google.com>, Vlastimil Babka <vbabka@suse.cz>,
David Hildenbrand <david@redhat.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>,
Randy Dunlap <rdunlap@infradead.org>,
kernel-hardening@lists.openwall.com,
linux-hardening@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v10 5/6] arm64: entry: Enable random_kstack_offset support
Date: Wed, 7 Apr 2021 22:35:03 +0100 [thread overview]
Message-ID: <20210407213502.GA16569@willie-the-truck> (raw)
In-Reply-To: <20210401232347.2791257-6-keescook@chromium.org>
On Thu, Apr 01, 2021 at 04:23:46PM -0700, Kees Cook wrote:
> Allow for a randomized stack offset on a per-syscall basis, with roughly
> 5 bits of entropy. (And include AAPCS rationale AAPCS thanks to Mark
> Rutland.)
>
> In order to avoid unconditional stack canaries on syscall entry (due to
> the use of alloca()), also disable stack protector to avoid triggering
> needless checks and slowing down the entry path. As there is no general
> way to control stack protector coverage with a function attribute[1],
> this must be disabled at the compilation unit level. This isn't a problem
> here, though, since stack protector was not triggered before: examining
> the resulting syscall.o, there are no changes in canary coverage (none
> before, none now).
>
> [1] a working __attribute__((no_stack_protector)) has been added to GCC
> and Clang but has not been released in any version yet:
> https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=346b302d09c1e6db56d9fe69048acb32fbb97845
> https://reviews.llvm.org/rG4fbf84c1732fca596ad1d6e96015e19760eb8a9b
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> arch/arm64/Kconfig | 1 +
> arch/arm64/kernel/Makefile | 5 +++++
> arch/arm64/kernel/syscall.c | 16 ++++++++++++++++
> 3 files changed, 22 insertions(+)
Acked-by: Will Deacon <will@kernel.org>
Will
next prev parent reply other threads:[~2021-04-07 21:35 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-01 23:23 [PATCH v10 0/6] Optionally randomize kernel stack offset each syscall Kees Cook
2021-04-01 23:23 ` [PATCH v10 1/6] jump_label: Provide CONFIG-driven build state defaults Kees Cook
2021-04-01 23:23 ` [PATCH v10 2/6] init_on_alloc: Optimize static branches Kees Cook
2021-04-01 23:23 ` [PATCH v10 3/6] stack: Optionally randomize kernel stack offset each syscall Kees Cook
2021-04-07 21:37 ` Will Deacon
2021-04-01 23:23 ` [PATCH v10 4/6] x86/entry: Enable random_kstack_offset support Kees Cook
2021-04-01 23:23 ` [PATCH v10 5/6] arm64: entry: " Kees Cook
2021-04-07 21:35 ` Will Deacon [this message]
2021-04-01 23:23 ` [PATCH v10 6/6] lkdtm: Add REPORT_STACK for checking stack offsets Kees Cook
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210407213502.GA16569@willie-the-truck \
--to=will@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=alex.popov@linux.com \
--cc=ard.biesheuvel@linaro.org \
--cc=catalin.marinas@arm.com \
--cc=corbet@lwn.net \
--cc=david@redhat.com \
--cc=elena.reshetova@intel.com \
--cc=glider@google.com \
--cc=jannh@google.com \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-hardening@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mark.rutland@arm.com \
--cc=peterz@infradead.org \
--cc=rdunlap@infradead.org \
--cc=rppt@linux.ibm.com \
--cc=tglx@linutronix.de \
--cc=vbabka@suse.cz \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox