From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: [PATCH v4 13/26] arm64: mte: Validate the PROT_MTE request via arch_validate_flags() Date: Fri, 15 May 2020 18:15:59 +0100 Message-ID: <20200515171612.1020-14-catalin.marinas@arm.com> References: <20200515171612.1020-1-catalin.marinas@arm.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Received: from foss.arm.com ([217.140.110.172]:59478 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726292AbgEORQs (ORCPT ); Fri, 15 May 2020 13:16:48 -0400 In-Reply-To: <20200515171612.1020-1-catalin.marinas@arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-arm-kernel@lists.infradead.org Cc: linux-mm@kvack.org, linux-arch@vger.kernel.org, Will Deacon , Dave P Martin , Vincenzo Frascino , Szabolcs Nagy , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne Make use of the newly introduced arch_validate_flags() hook to sanity-check the PROT_MTE request passed to mmap() and mprotect(). If the mapping does not support MTE, these syscalls will return -EINVAL. Signed-off-by: Catalin Marinas Cc: Will Deacon --- arch/arm64/include/asm/mman.h | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h index c77a23869223..5c356d1ca266 100644 --- a/arch/arm64/include/asm/mman.h +++ b/arch/arm64/include/asm/mman.h @@ -44,7 +44,11 @@ static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags) static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags) { - return (vm_flags & VM_MTE) && (vm_flags & VM_MTE_ALLOWED) ? + /* + * Checking for VM_MTE only is sufficient since arch_validate_flags() + * does not permit (VM_MTE & !VM_MTE_ALLOWED). + */ + return (vm_flags & VM_MTE) ? __pgprot(PTE_ATTRINDX(MT_NORMAL_TAGGED)) : __pgprot(0); } @@ -61,4 +65,14 @@ static inline bool arch_validate_prot(unsigned long prot, unsigned long addr) } #define arch_validate_prot arch_validate_prot +static inline bool arch_validate_flags(unsigned long flags) +{ + if (!system_supports_mte()) + return true; + + /* only allow VM_MTE if VM_MTE_ALLOWED has been set previously */ + return !(flags & VM_MTE) || (flags & VM_MTE_ALLOWED); +} +#define arch_validate_flags arch_validate_flags + #endif /* !__ASM_MMAN_H__ */