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Message-Id: <20170311000501.46607-4-thgarnie@google.com>
Date: Fri, 10 Mar 2017 16:05:01 -0800
From: Thomas Garnier <thgarnie@...gle.com>
To: Martin Schwidefsky <schwidefsky@...ibm.com>,
Heiko Carstens <heiko.carstens@...ibm.com>,
David Howells <dhowells@...hat.com>,
Arnd Bergmann <arnd@...db.de>,
Al Viro <viro@...iv.linux.org.uk>,
Dave Hansen <dave.hansen@...el.com>,
Thomas Garnier <thgarnie@...gle.com>,
René Nyffenegger <mail@...enyffenegger.ch>,
Andrew Morton <akpm@...ux-foundation.org>,
Kees Cook <keescook@...omium.org>,
"Paul E . McKenney" <paulmck@...ux.vnet.ibm.com>,
Andy Lutomirski <luto@...nel.org>,
Ard Biesheuvel <ard.biesheuvel@...aro.org>,
Nicolas Pitre <nicolas.pitre@...aro.org>,
Petr Mladek <pmladek@...e.com>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
Helge Deller <deller@....de>,
Rik van Riel <riel@...hat.com>,
Ingo Molnar <mingo@...nel.org>,
John Stultz <john.stultz@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
Oleg Nesterov <oleg@...hat.com>,
Stephen Smalley <sds@...ho.nsa.gov>,
Pavel Tikhomirov <ptikhomirov@...tuozzo.com>,
Frederic Weisbecker <fweisbec@...il.com>,
Stanislav Kinsburskiy <skinsbursky@...tuozzo.com>,
Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Dmitry Safonov <dsafonov@...tuozzo.com>,
Borislav Petkov <bp@...en8.de>,
Josh Poimboeuf <jpoimboe@...hat.com>,
Brian Gerst <brgerst@...il.com>,
Jan Beulich <JBeulich@...e.com>,
Christian Borntraeger <borntraeger@...ibm.com>,
Fenghua Yu <fenghua.yu@...el.com>,
He Chen <he.chen@...ux.intel.com>,
Russell King <linux@...linux.org.uk>,
Vladimir Murzin <vladimir.murzin@....com>,
Will Deacon <will.deacon@....com>,
Catalin Marinas <catalin.marinas@....com>,
Mark Rutland <mark.rutland@....com>,
James Morse <james.morse@....com>,
"David A . Long" <dave.long@...aro.org>,
Pratyush Anand <panand@...hat.com>,
Laura Abbott <labbott@...hat.com>,
Andre Przywara <andre.przywara@....com>,
Chris Metcalf <cmetcalf@...lanox.com>
Cc: linux-s390@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-api@...r.kernel.org,
x86@...nel.org,
linux-arm-kernel@...ts.infradead.org,
kernel-hardening@...ts.openwall.com
Subject: [PATCH v3 4/4] arm64/syscalls: Specific usage of verify_pre_usermode_state
Implement specific usage of verify_pre_usermode_state for user-mode
returns for arm64.
---
Based on next-20170308
---
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/entry.S | 25 +++++++++++++++++++++++++
2 files changed, 26 insertions(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 896eba61e5ed..da54774838d8 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -24,6 +24,7 @@ config ARM64
select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
select ARCH_WANT_FRAME_POINTERS
select ARCH_HAS_UBSAN_SANITIZE_ALL
+ select ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE
select ARM_AMBA
select ARM_ARCH_TIMER
select ARM_GIC
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 43512d4d7df2..685b43771ac9 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -744,6 +744,10 @@ ENDPROC(cpu_switch_to)
ret_fast_syscall:
disable_irq // disable interrupts
str x0, [sp, #S_X0] // returned x0
+ ldr x2, [tsk, #TSK_TI_ADDR_LIMIT] // check addr limit change
+ mov x1, #TASK_SIZE_64
+ cmp x2, x1
+ b.ne addr_limit_fail
ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for syscall tracing
and x2, x1, #_TIF_SYSCALL_WORK
cbnz x2, ret_fast_syscall_trace
@@ -771,6 +775,11 @@ work_pending:
*/
ret_to_user:
disable_irq // disable interrupts
+ ldr x2, [tsk, #TSK_TI_ADDR_LIMIT] // check addr limit change
+ mov x1, #TASK_SIZE_64
+ cmp x2, x1
+ b.ne addr_limit_fail
+
ldr x1, [tsk, #TSK_TI_FLAGS]
and x2, x1, #_TIF_WORK_MASK
cbnz x2, work_pending
@@ -779,6 +788,22 @@ finish_ret_to_user:
kernel_exit 0
ENDPROC(ret_to_user)
+addr_limit_fail:
+#ifdef CONFIG_BUG_ON_DATA_CORRUPTION
+ stp x0, lr, [sp,#-16]!
+ bl verify_pre_usermode_state
+ ldp x0, lr, [sp],#16
+#else
+ /*
+ * Similar to set_fs(USER_DS) in verify_pre_usermode_state without a
+ * warning.
+ */
+ mov x2, #TASK_SIZE_64
+ str x2, [tsk, #TSK_TI_ADDR_LIMIT]
+ ALTERNATIVE(nop, SET_PSTATE_UAO(0), ARM64_HAS_UAO, CONFIG_ARM64_UAO)
+#endif
+ ret lr
+
/*
* This is how we return from a fork.
*/
--
2.12.0.246.ga2ecc84866-goog
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