From: Thomas Garnier <thgarnie@google.com>
To: "Martin Schwidefsky" <schwidefsky@de.ibm.com>,
"Heiko Carstens" <heiko.carstens@de.ibm.com>,
"Dave Hansen" <dave.hansen@intel.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"David Howells" <dhowells@redhat.com>,
"René Nyffenegger" <mail@renenyffenegger.ch>,
"Thomas Garnier" <thgarnie@google.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
"Ingo Molnar" <mingo@kernel.org>,
"Eric W . Biederman" <ebiederm@xmission.com>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Oleg Nesterov" <oleg@redhat.com>,
"Pavel Tikhomirov" <ptikhomirov@virtuozzo.com>,
"Ingo Molnar" <mingo@redhat.com>,
"H . Peter Anvin" <hpa@zytor.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Kees Cook" <keescook@chromium.org>,
"Rik van Riel" <riel@redhat.com>,
"Josh Poimboeuf" <jpoimboe@redhat.com>,
"Borislav Petkov" <bp@alien8.de>
Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, x86@kernel.org,
linux-arm-kernel@lists.infradead.org,
kernel-hardening@lists.openwall.com
Subject: [PATCH v8 3/4] arm/syscalls: Optimize address limit check
Date: Wed, 26 Apr 2017 11:34:24 -0700 [thread overview]
Message-ID: <20170426183425.32158-3-thgarnie@google.com> (raw)
In-Reply-To: <20170426183425.32158-1-thgarnie@google.com>
Disable the generic address limit check in favor of an architecture
specific optimized implementation.
The address limit is checked on each syscall return path to user-mode
path as well as the irq user-mode return function. If the address limit
was changed, a generic handler is called to stop the kernel on an
explicit check.
Signed-off-by: Thomas Garnier <thgarnie@google.com>
---
Based on next-20170426
---
arch/arm/Kconfig | 1 +
arch/arm/kernel/entry-common.S | 10 +++++++++-
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4c1a35f15838..f17f30084a4e 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -12,6 +12,7 @@ config ARM
select ARCH_HAVE_CUSTOM_GPIO_H
select ARCH_HAS_GCOV_PROFILE_ALL
select ARCH_MIGHT_HAVE_PC_PARPORT
+ select ADDR_LIMIT_CHECK
select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
select ARCH_SUPPORTS_ATOMIC_RMW
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index eb5cd77bf1d8..c83927498f40 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -12,6 +12,7 @@
#include <asm/unistd.h>
#include <asm/ftrace.h>
#include <asm/unwind.h>
+#include <asm/memory.h>
#ifdef CONFIG_AEABI
#include <asm/unistd-oabi.h>
#endif
@@ -27,7 +28,6 @@
#include "entry-header.S"
-
.align 5
#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING))
/*
@@ -40,9 +40,12 @@ ret_fast_syscall:
UNWIND(.fnstart )
UNWIND(.cantunwind )
disable_irq_notrace @ disable interrupts
+ ldr r2, [tsk, #TI_ADDR_LIMIT]
ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
bne fast_work_pending
+ cmp r2, #TASK_SIZE
+ blne addr_limit_check_failed
/* perform architecture specific actions before user return */
arch_ret_to_user r1, lr
@@ -66,6 +69,7 @@ ret_fast_syscall:
UNWIND(.cantunwind )
str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
disable_irq_notrace @ disable interrupts
+ ldr r2, [tsk, #TI_ADDR_LIMIT]
ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing
tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
beq no_work_pending
@@ -82,6 +86,7 @@ slow_work_pending:
mov r2, why @ 'syscall'
bl do_work_pending
cmp r0, #0
+ ldreq r2, [tsk, #TI_ADDR_LIMIT]
beq no_work_pending
movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE)
ldmia sp, {r0 - r6} @ have to reload r0 - r6
@@ -99,9 +104,12 @@ ret_slow_syscall:
disable_irq_notrace @ disable interrupts
ENTRY(ret_to_user_from_irq)
ldr r1, [tsk, #TI_FLAGS]
+ ldr r2, [tsk, #TI_ADDR_LIMIT]
tst r1, #_TIF_WORK_MASK
bne slow_work_pending
no_work_pending:
+ cmp r2, #TASK_SIZE
+ blne addr_limit_check_failed
asm_trace_hardirqs_on save = 0
/* perform architecture specific actions before user return */
--
2.13.0.rc0.306.g87b477812d-goog
next prev parent reply other threads:[~2017-04-26 18:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-26 18:34 [PATCH v8 1/4] syscalls: Verify address limit before returning to user-mode Thomas Garnier
2017-04-26 18:34 ` [PATCH v8 2/4] x86/syscalls: Optimize address limit check Thomas Garnier
2017-04-26 18:34 ` Thomas Garnier [this message]
2017-04-26 18:34 ` [PATCH v8 4/4] arm64/syscalls: " Thomas Garnier
[not found] ` <20170426183425.32158-1-thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2017-04-27 6:49 ` [PATCH v8 1/4] syscalls: Verify address limit before returning to user-mode Ingo Molnar
2017-04-27 14:16 ` Thomas Garnier
[not found] ` <CAJcbSZENjCgn3TNDGzCBBSOXMvbTX8mBO7Trugdb5VRzhxwmHg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-04-27 14:42 ` Thomas Garnier
[not found] ` <20170427144227.113630-1-thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2017-04-28 6:35 ` Ingo Molnar
2017-04-28 6:33 ` Ingo Molnar
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