Path: csiph.com!aioe.org!bofh.it!news.nic.it!robomod From: Thomas Garnier Newsgroups: linux.kernel Subject: [PATCH v5 3/4] arm/syscalls: Specific usage of verify_pre_usermode_state Date: Thu, 23 Mar 2017 18:30:01 +0100 Message-ID: References: Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=jBcQfCvgcsLJjvtwLYJH8skdoKJL/5IprG1RrnK5JPQ=; b=POJRDSrB42KPoVlPb4Hk49oHaMcx4p82XDp+fQ+b6ZLUKUr7JFaAbCrBLeDuwFwK/U Q5Da78g/uvgZVc6stSq3mEjcS/sivjMIcBA2XcEFfO9HfGBSDDoAc/y9rpDOi0kjBDgO 3RQJ3fkb8lyfK6EHOPZwUKG0CWzDexKRyo1P5dbhUf1SN7zy5d6uYH4Q4jNtHN/iTCXd nfB2D+gqTQgPO79GURcT1wRo7RqrXCoqSK95A0IoJExV9qK5cjSMDc/XWBQK2Czn4jsB YDRpo9+lCJSyXNZWhCVQ5ElMkSognf7s1CJUha/Fp5nOyhZ6zx9qU1vIB6CdC3aGXwik BlfA== X-Google-Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=jBcQfCvgcsLJjvtwLYJH8skdoKJL/5IprG1RrnK5JPQ=; b=FrxNzzrhxqOZnFfOPp7814BkMVSvQrXmc2h+hRCnN4aTbcnOZFNZ/kfrX8S0jg6tdD OHs6LDRql570YSYUFTCWC7yZ4QbajgY2HJtmZPeRlaHGInaOFGM9jp8gxNZNd+UxTQjS LZUWW6dv5rJQ/ihOJgfeEPmtV8ApXkI+WJXC+qayMbC2LJxC6qa8cK8m4Qo0qJN8b/e7 fY1UzrrLNQSdQe6SviZ6URq6aMeE1TyuM39mcc/BHIXZGME13k4g1MV6MDIOCgqKlq4Z NscdC0My2HNH/k94HsLwEClZfLa7f9NsXNJqlOUs5ljUnxTUU8d4qUD8FkC/HDPGqwV0 yXqg== X-Gm-Message-State: AFeK/H1i2ewn54TlwAv1D/GzGG0Gz0lWCtVFk5GFaXvc0w9YcKhttUaKIIewsUWpBECjfe8d X-Received: by 10.98.155.28 with SMTP id r28mr4182701pfd.212.1490289925006; Thu, 23 Mar 2017 10:25:25 -0700 (PDT) X-Mailer: git-send-email 2.12.1.500.gab5fba24ee-goog Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 98 Organization: linux.* mail to news gateway X-Original-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 X-Original-Date: Thu, 23 Mar 2017 10:25:14 -0700 X-Original-Message-ID: <20170323172515.27950-3-thgarnie@google.com> X-Original-References: <20170323172515.27950-1-thgarnie@google.com> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1607730 Implement specific usage of verify_pre_usermode_state for user-mode returns for arm. --- Based on next-20170322 --- arch/arm/Kconfig | 1 + arch/arm/kernel/entry-common.S | 16 +++++++++++++++- 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index fcbc5ef1ec69..10c6dc3dfff9 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..88c72c4e44ad 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 @@ -27,7 +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_fail /* 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_fail asm_trace_hardirqs_on save = 0 /* perform architecture specific actions before user return */ @@ -125,6 +133,12 @@ ENTRY(ret_from_fork) b ret_slow_syscall ENDPROC(ret_from_fork) +addr_limit_fail: + stmfd sp!, {r0, lr} + bl asm_verify_pre_usermode_state + ldmfd sp!, {r0, lr} + ret lr + /*============================================================================= * SWI handler *----------------------------------------------------------------------------- -- 2.12.1.500.gab5fba24ee-goog