From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vincenzo Frascino Subject: [PATCH] arm64: compat: Reduce address limit Date: Mon, 1 Apr 2019 11:32:01 +0100 Message-ID: <20190401103201.9268-1-vincenzo.frascino@arm.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Sender: stable-owner@vger.kernel.org To: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: stable@vger.kernel.org, Catalin Marinas , Will Deacon , Jann Horn List-Id: linux-arch.vger.kernel.org Currently, compat tasks running on arm64 can allocate memory up to TASK_SIZE_32 (UL(0x100000000)). This means that mmap() allocations, if we treat them as returning an array, are not compliant with the sections 6.5.8 of the C standard (C99) which states that: "If the expression P points to an element of an array object and the expression Q points to the last element of the same array object, the pointer expression Q+1 compares greater than P". Redefine TASK_SIZE_32 to address the issue. Cc: Catalin Marinas Cc: Will Deacon Cc: Jann Horn Reported-by: Jann Horn Signed-off-by: Vincenzo Frascino --- arch/arm64/include/asm/processor.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 5d9ce62bdebd..f8235f7df29b 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -57,7 +57,11 @@ #define TASK_SIZE_64 (UL(1) << vabits_user) #ifdef CONFIG_COMPAT +#ifdef CONFIG_ARM64_64K_PAGES #define TASK_SIZE_32 UL(0x100000000) +#else +#define TASK_SIZE_32 (UL(0x100000000) - PAGE_SIZE) +#endif /* CONFIG_ARM64_64K_PAGES */ #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \ TASK_SIZE_32 : TASK_SIZE_64) #define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \ -- 2.21.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com ([217.140.101.70]:60276 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725868AbfDAKcS (ORCPT ); Mon, 1 Apr 2019 06:32:18 -0400 From: Vincenzo Frascino Subject: [PATCH] arm64: compat: Reduce address limit Date: Mon, 1 Apr 2019 11:32:01 +0100 Message-ID: <20190401103201.9268-1-vincenzo.frascino@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: stable@vger.kernel.org, Catalin Marinas , Will Deacon , Jann Horn Message-ID: <20190401103201.EnsUAKukUYdSw7G9nEMsq-D6MMy2KSl8iGIZmtVJmsY@z> Currently, compat tasks running on arm64 can allocate memory up to TASK_SIZE_32 (UL(0x100000000)). This means that mmap() allocations, if we treat them as returning an array, are not compliant with the sections 6.5.8 of the C standard (C99) which states that: "If the expression P points to an element of an array object and the expression Q points to the last element of the same array object, the pointer expression Q+1 compares greater than P". Redefine TASK_SIZE_32 to address the issue. Cc: Catalin Marinas Cc: Will Deacon Cc: Jann Horn Reported-by: Jann Horn Signed-off-by: Vincenzo Frascino --- arch/arm64/include/asm/processor.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 5d9ce62bdebd..f8235f7df29b 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -57,7 +57,11 @@ #define TASK_SIZE_64 (UL(1) << vabits_user) #ifdef CONFIG_COMPAT +#ifdef CONFIG_ARM64_64K_PAGES #define TASK_SIZE_32 UL(0x100000000) +#else +#define TASK_SIZE_32 (UL(0x100000000) - PAGE_SIZE) +#endif /* CONFIG_ARM64_64K_PAGES */ #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \ TASK_SIZE_32 : TASK_SIZE_64) #define TASK_SIZE_OF(tsk) (test_tsk_thread_flag(tsk, TIF_32BIT) ? \ -- 2.21.0