From: Jiri Kosina <jikos@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>,
"Woodhouse, David" <dwmw@amazon.co.uk>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
Oleg Nesterov <oleg@redhat.com>,
Tim Chen <tim.c.chen@linux.intel.com>
Subject: [PATCH v2 0/3] Harden spectrev2 userspace-userspace protection
Date: Mon, 3 Sep 2018 14:45:13 +0200 (CEST) [thread overview]
Message-ID: <nycvar.YFH.7.76.1809031418260.25787@cbobk.fhfr.pm> (raw)
In-Reply-To: <nycvar.YFH.7.76.1808312242130.25787@cbobk.fhfr.pm>
[ added a few more CCs for v2 ]
Currently, linux kernel is basically not preventing userspace-userspace
spectrev2 attack, because:
- IBPB is basically unused (issued only for tasks that marked themselves
explicitly non-dumpable, which is absolutely negligible minority of all
software out there), therefore cross-process branch buffer posioning
using spectrev2 is possible
- STIBP is completely unused, therefore cross-process branch buffer
poisoning using spectrev2 between processess running on two HT siblings
thread s is possible
This patchset changes IBPB semantics, so that it's now applied whenever
context-switching between processess that can't use ptrace() to achieve
the same. This admittedly comes with extra overhad on a context switch;
systems that don't care about could disable the mitigation using
nospectre_v2 boot option.
The IBPB implementaion is heavily based on original patches by Tim Chen.
In addition to that, we unconditionally turn STIBP on so that HT siblings
always have separate branch buffers.
We've been carrying IBPB implementation with the same semantics in our
(SUSE) trees since january disclosure; STIBP was more or less ignored up
to today.
Jiri Kosina (3):
ptrace: Provide ___ptrace_may_access() that can be applied on arbitrary tasks
x86/speculation: Apply IBPB more strictly to avoid cross-process spectre v2 leak
x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation
arch/x86/kernel/cpu/bugs.c | 12 ++++++++++++
arch/x86/mm/tlb.c | 15 ++++++---------
include/linux/ptrace.h | 15 +++++++++++++++
kernel/ptrace.c | 17 +++++++++++++----
4 files changed, 46 insertions(+), 13 deletions(-)
--
Jiri Kosina
SUSE Labs
next prev parent reply other threads:[~2018-09-03 12:45 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-31 20:56 [PATCH] x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation Jiri Kosina
2018-09-03 8:51 ` Jiri Kosina
2018-09-03 12:45 ` Jiri Kosina [this message]
2018-09-04 14:23 ` [PATCH v3 0/3] Harden spectrev2 userspace-userspace protection Jiri Kosina
2018-09-04 14:40 ` [PATCH v3 1/3] ptrace: Provide ___ptrace_may_access() that can be applied on arbitrary tasks Jiri Kosina
2018-09-04 16:13 ` Thomas Gleixner
2018-09-04 16:21 ` Thomas Gleixner
2018-09-04 17:26 ` Tim Chen
2018-09-04 17:35 ` Jiri Kosina
2018-09-04 18:10 ` Schaufler, Casey
2018-09-04 18:48 ` Jiri Kosina
2018-09-04 23:26 ` Tim Chen
2018-09-05 6:22 ` Jiri Kosina
2018-09-05 15:58 ` Andi Kleen
2018-09-05 18:04 ` Andrea Arcangeli
2018-09-05 18:29 ` Jiri Kosina
2018-09-05 18:40 ` Andrea Arcangeli
2018-09-05 18:42 ` Jiri Kosina
2018-09-05 19:03 ` Peter Zijlstra
2018-09-05 19:27 ` Schaufler, Casey
2018-09-05 20:02 ` Jiri Kosina
2018-09-05 18:26 ` Thomas Gleixner
2018-09-05 18:35 ` Jiri Kosina
2018-09-04 23:37 ` Andrea Arcangeli
2018-09-05 1:00 ` Schaufler, Casey
2018-09-05 2:38 ` Andrea Arcangeli
2018-09-05 8:00 ` Peter Zijlstra
2018-09-05 15:37 ` Schaufler, Casey
2018-09-05 7:51 ` Peter Zijlstra
2018-09-04 14:42 ` [PATCH v3 2/3] x86/speculation: apply IBPB more strictly to avoid cross-process data leak Jiri Kosina
2018-09-04 16:18 ` Thomas Gleixner
2018-09-05 7:59 ` Peter Zijlstra
2018-09-05 8:02 ` Jiri Kosina
2018-09-05 9:40 ` Peter Zijlstra
2018-09-05 7:52 ` Peter Zijlstra
2018-09-05 7:55 ` Jiri Kosina
2018-09-04 14:42 ` [PATCH v3 3/3] x86/speculation: Enable cross-hyperthread spectre v2 STIBP mitigation Jiri Kosina
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