From: Will Deacon <will.deacon@arm.com>
To: linux-kernel@vger.kernel.org
Cc: Will Deacon <will.deacon@arm.com>,
Kees Cook <keescook@chromium.org>, Jann Horn <jannh@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@suse.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: [RFC PATCH 0/4] Allow tasks to have their user stack pointer sanity checked
Date: Mon, 11 Feb 2019 17:59:31 +0000 [thread overview]
Message-ID: <20190211175935.4602-1-will.deacon@arm.com> (raw)
Hi all,
I attended an interesting talk at LCA last month that described some of the
security features deployed in OpenBSD [1]. One hardening feature that piqued
my interest was, on syscall entry and page faults from userspace, checking
that the user stack pointer for a task points at pages that were either
allocated by the kernel for the initial process stack of mapped with mmap()
using the MAP_STACK flag. This acts as a basic defense against stack
pivoting attacks.
The problem with this checking is that it is a retrospective tightening
of the ABI, but that hasn't stopped me hacking it together behind a couple
of prctl() options.
Anyway, it was fun to implement so I figured I'd post it as an RFC.
Will
[1] https://2019.linux.conf.au/schedule/presentation/164/
Cc: Kees Cook <keescook@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
--->8
Will Deacon (4):
mm: Check user stack pointer is mapped with MAP_STACK
mm: Expose user stack pointer checking via prctl()
mm: Add kconfig entries for user stack pointer checking
arm64: Check user stack pointer on syscall entry
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/syscall.c | 4 +++
include/linux/mm.h | 15 +++++++++-
include/linux/mman.h | 3 +-
include/linux/sched.h | 4 +++
include/uapi/linux/prctl.h | 5 ++++
kernel/sys.c | 5 ++++
mm/Kconfig | 17 ++++++++++++
mm/memory.c | 67 +++++++++++++++++++++++++++++++++++++++++++++
9 files changed, 119 insertions(+), 2 deletions(-)
--
2.11.0
next reply other threads:[~2019-02-11 17:59 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-11 17:59 Will Deacon [this message]
2019-02-11 17:59 ` [RFC PATCH 1/4] mm: Check user stack pointer is mapped with MAP_STACK Will Deacon
2019-02-11 17:59 ` [RFC PATCH 2/4] mm: Expose user stack pointer checking via prctl() Will Deacon
2019-02-11 17:59 ` [RFC PATCH 3/4] mm: Add kconfig entries for user stack pointer checking Will Deacon
2019-02-11 17:59 ` [RFC PATCH 4/4] arm64: Check user stack pointer on syscall entry Will Deacon
2019-02-11 19:12 ` [RFC PATCH 0/4] Allow tasks to have their user stack pointer sanity checked Kees Cook
2019-02-13 13:19 ` Will Deacon
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