From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Garnier Date: Wed, 8 Mar 2017 13:38:43 -0800 Message-Id: <20170308213844.131877-3-thgarnie@google.com> In-Reply-To: <20170308213844.131877-1-thgarnie@google.com> References: <20170308213844.131877-1-thgarnie@google.com> Subject: [kernel-hardening] [PATCH v1 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state To: Arnd Bergmann , David Howells , Al Viro , Dave Hansen , Thomas Garnier , =?UTF-8?q?Ren=C3=A9=20Nyffenegger?= , Andrew Morton , Kees Cook , "Paul E . McKenney" , Petr Mladek , Andy Lutomirski , Ard Biesheuvel , Nicolas Pitre , Sebastian Andrzej Siewior , Sergey Senozhatsky , Helge Deller , Rik van Riel , Ingo Molnar , John Stultz , Thomas Gleixner , Oleg Nesterov , Stanislav Kinsburskiy , Pavel Tikhomirov , Stephen Smalley , Frederic Weisbecker , Ingo Molnar , "H . Peter Anvin" , Paolo Bonzini , Dmitry Safonov , Borislav Petkov , Josh Poimboeuf , Brian Gerst , Alexander Potapenko , Jan Beulich , Russell King , Will Deacon , Catalin Marinas , Mark Rutland , James Morse , Chris Metcalf , Laura Abbott , Andre Przywara 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: 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 | 5 +++++ 2 files changed, 6 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..80cfdc7fabde 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -39,6 +39,9 @@ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind ) + push {r0} @ save returned r0 + bl verify_pre_usermode_state + pop {r0} @ restore r0 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 +68,7 @@ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind ) str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 + bl 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 +267,7 @@ __sys_trace: __sys_trace_return: str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 + bl verify_pre_usermode_state mov r0, sp bl syscall_trace_exit b ret_slow_syscall -- 2.12.0.246.ga2ecc84866-goog