From: tip-bot for Dan Williams <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: luto@kernel.org, torvalds@linux-foundation.org,
tglx@linutronix.de, linux-kernel@vger.kernel.org, hpa@zytor.com,
dan.j.williams@intel.com, mingo@kernel.org
Subject: [tip:x86/pti] x86/syscall: Sanitize syscall table de-references under speculation
Date: Tue, 30 Jan 2018 14:37:14 -0800 [thread overview]
Message-ID: <tip-2fbd7af5af8665d18bcefae3e9700be07e22b681@git.kernel.org> (raw)
In-Reply-To: <151727417984.33451.1216731042505722161.stgit@dwillia2-desk3.amr.corp.intel.com>
Commit-ID: 2fbd7af5af8665d18bcefae3e9700be07e22b681
Gitweb: https://git.kernel.org/tip/2fbd7af5af8665d18bcefae3e9700be07e22b681
Author: Dan Williams <dan.j.williams@intel.com>
AuthorDate: Mon, 29 Jan 2018 17:02:59 -0800
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 30 Jan 2018 21:54:31 +0100
x86/syscall: Sanitize syscall table de-references under speculation
The syscall table base is a user controlled function pointer in kernel
space. Use array_index_nospec() to prevent any out of bounds speculation.
While retpoline prevents speculating into a userspace directed target it
does not stop the pointer de-reference, the concern is leaking memory
relative to the syscall table base, by observing instruction cache
behavior.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: kernel-hardening@lists.openwall.com
Cc: gregkh@linuxfoundation.org
Cc: Andy Lutomirski <luto@kernel.org>
Cc: alan@linux.intel.com
Link: https://lkml.kernel.org/r/151727417984.33451.1216731042505722161.stgit@dwillia2-desk3.amr.corp.intel.com
---
arch/x86/entry/common.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 9908134..21dbdf0 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -21,6 +21,7 @@
#include <linux/export.h>
#include <linux/context_tracking.h>
#include <linux/user-return-notifier.h>
+#include <linux/nospec.h>
#include <linux/uprobes.h>
#include <linux/livepatch.h>
#include <linux/syscalls.h>
@@ -282,7 +283,8 @@ __visible void do_syscall_64(struct pt_regs *regs)
* regs->orig_ax, which changes the behavior of some syscalls.
*/
if (likely((nr & __SYSCALL_MASK) < NR_syscalls)) {
- regs->ax = sys_call_table[nr & __SYSCALL_MASK](
+ nr = array_index_nospec(nr & __SYSCALL_MASK, NR_syscalls);
+ regs->ax = sys_call_table[nr](
regs->di, regs->si, regs->dx,
regs->r10, regs->r8, regs->r9);
}
@@ -318,6 +320,7 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs)
}
if (likely(nr < IA32_NR_syscalls)) {
+ nr = array_index_nospec(nr, IA32_NR_syscalls);
/*
* It's possible that a 32-bit syscall implementation
* takes a 64-bit parameter but nonetheless assumes that
next prev parent reply other threads:[~2018-01-30 22:39 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-30 1:02 [PATCH v6 00/13] spectre variant1 mitigations for tip/x86/pti Dan Williams
2018-01-30 1:02 ` [PATCH v6 01/13] Documentation: document array_index_nospec Dan Williams
2018-01-30 22:33 ` [tip:x86/pti] Documentation: Document array_index_nospec tip-bot for Mark Rutland
2018-01-30 1:02 ` [PATCH v6 02/13] array_index_nospec: sanitize speculative array de-references Dan Williams
2018-01-30 22:34 ` [tip:x86/pti] array_index_nospec: Sanitize " tip-bot for Dan Williams
2018-02-16 8:55 ` [PATCH v6 02/13] array_index_nospec: sanitize " Christian Borntraeger
2018-01-30 1:02 ` [PATCH v6 03/13] x86: implement array_index_mask_nospec Dan Williams
2018-01-30 22:34 ` [tip:x86/pti] x86: Implement array_index_mask_nospec tip-bot for Dan Williams
2018-01-30 1:02 ` [PATCH v6 04/13] x86: introduce barrier_nospec Dan Williams
2018-01-30 22:35 ` [tip:x86/pti] x86: Introduce barrier_nospec tip-bot for Dan Williams
2018-01-30 1:02 ` [PATCH v6 05/13] x86: introduce __uaccess_begin_nospec Dan Williams
2018-01-30 22:35 ` [tip:x86/pti] x86: Introduce __uaccess_begin_nospec() and uaccess_try_nospec tip-bot for Dan Williams
2018-01-30 1:02 ` [PATCH v6 06/13] x86, usercopy: replace open coded stac/clac with __uaccess_{begin, end} Dan Williams
2018-01-30 22:35 ` [tip:x86/pti] x86/usercopy: Replace " tip-bot for Dan Williams
2018-01-30 1:02 ` [PATCH v6 07/13] x86, __get_user: use __uaccess_begin_nospec Dan Williams
2018-01-30 22:36 ` [tip:x86/pti] x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec tip-bot for Dan Williams
2018-01-30 1:02 ` [PATCH v6 08/13] x86, get_user: use pointer masking to limit speculation Dan Williams
2018-01-30 22:36 ` [tip:x86/pti] x86/get_user: Use " tip-bot for Dan Williams
2018-01-30 1:02 ` [PATCH v6 09/13] x86: sanitize syscall table de-references under speculation Dan Williams
2018-01-30 22:37 ` tip-bot for Dan Williams [this message]
2018-01-30 1:03 ` [PATCH v6 10/13] vfs, fdtable: prevent bounds-check bypass via speculative execution Dan Williams
2018-01-30 22:37 ` [tip:x86/pti] vfs, fdtable: Prevent " tip-bot for Dan Williams
2018-01-30 1:03 ` [PATCH v6 11/13] kvm, x86: update spectre-v1 mitigation Dan Williams
2018-01-31 3:22 ` Dan Williams
2018-01-31 8:07 ` Thomas Gleixner
2018-01-31 13:49 ` Paolo Bonzini
2018-01-31 15:42 ` Thomas Gleixner
2018-01-30 1:03 ` [PATCH v6 12/13] nl80211: sanitize array index in parse_txq_params Dan Williams
2018-01-30 22:38 ` [tip:x86/pti] nl80211: Sanitize " tip-bot for Dan Williams
2018-01-30 1:03 ` [PATCH v6 13/13] x86/spectre: report get_user mitigation for spectre_v1 Dan Williams
2018-01-30 22:38 ` [tip:x86/pti] x86/spectre: Report " tip-bot for Dan Williams
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