From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Garnier Subject: [PATCH v2 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state Date: Wed, 8 Mar 2017 17:24:55 -0800 Message-ID: <20170309012456.5631-3-thgarnie@google.com> References: <20170309012456.5631-1-thgarnie@google.com> Return-path: List-Post: List-Help: List-Unsubscribe: List-Subscribe: In-Reply-To: <20170309012456.5631-1-thgarnie@google.com> To: David Howells , Dave Hansen , Arnd Bergmann , Al Viro , =?UTF-8?q?Ren=C3=A9=20Nyffenegger?= , Thomas Garnier , Andrew Morton , Kees Cook , "Paul E . McKenney" , "David S . Miller" , Andy Lutomirski , Ard Biesheuvel , Nicolas Pitre , Petr Mladek , Sebastian Andrzej Siewior , Sergey Senozhatsky , Helge Deller , Rik van Riel , Ingo Molnar , Oleg Nesterov , John Stultz , Thomas Gleixner , Pavel Cc: linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, kernel-hardening@lists.openwall.com List-Id: linux-api@vger.kernel.org Implement specific usage of verify_pre_usermode_state for user-mode returns for arm. --- Based on next-20170308 --- arch/arm/Kconfig | 1 + arch/arm/kernel/entry-common.S | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 0d4e71b42c77..704fd8f197fa 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 ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE 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..a2cdf3d7bcff 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -12,6 +12,7 @@ #include #include #include +#include #ifdef CONFIG_AEABI #include #endif @@ -27,6 +28,23 @@ #include "entry-header.S" +#ifdef CONFIG_BUG_ON_DATA_CORRUPTION +.macro VERIFY_PRE_USERMODE_STATE +#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING)) + stmdb sp!, {r0} + bl verify_pre_usermode_state + ldmia sp!, {r0} +#else + bl verify_pre_usermode_state +#endif +.endm +#else +/* Similar to set_fs(USER_DS) in verify_pre_usermode_state without a warning. */ +.macro VERIFY_PRE_USERMODE_STATE + mov r1, $TASK_SIZE + str r1, [tsk, #TI_ADDR_LIMIT] +.endm +#endif .align 5 #if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING)) @@ -39,6 +57,7 @@ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind ) + VERIFY_PRE_USERMODE_STATE disable_irq_notrace @ disable interrupts ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK @@ -65,6 +84,7 @@ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind ) str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 + VERIFY_PRE_USERMODE_STATE disable_irq_notrace @ disable interrupts ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK @@ -263,6 +283,7 @@ __sys_trace: __sys_trace_return: str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 + VERIFY_PRE_USERMODE_STATE mov r0, sp bl syscall_trace_exit b ret_slow_syscall -- 2.12.0.246.ga2ecc84866-goog