From mboxrd@z Thu Jan 1 00:00:00 1970 From: Catalin Marinas Subject: [PATCH v5 14/25] arm64: mte: Validate the PROT_MTE request via arch_validate_flags() Date: Wed, 24 Jun 2020 18:52:33 +0100 Message-ID: <20200624175244.25837-15-catalin.marinas@arm.com> References: <20200624175244.25837-1-catalin.marinas@arm.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Received: from mail.kernel.org ([198.145.29.99]:55302 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405857AbgFXRxU (ORCPT ); Wed, 24 Jun 2020 13:53:20 -0400 In-Reply-To: <20200624175244.25837-1-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 , Andrew Morton 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 | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h index b01051be7750..e3e28f7daf62 100644 --- a/arch/arm64/include/asm/mman.h +++ b/arch/arm64/include/asm/mman.h @@ -49,8 +49,10 @@ static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags) * register (1) as VM_MTE in the vma->vm_flags and (2) as * VM_MTE_ALLOWED. Note that the latter can only be set during the * mmap() call since mprotect() does not accept MAP_* flags. + * Checking for VM_MTE only is sufficient since arch_validate_flags() + * does not permit (VM_MTE & !VM_MTE_ALLOWED). */ - if ((vm_flags & VM_MTE) && (vm_flags & VM_MTE_ALLOWED)) + if (vm_flags & VM_MTE) prot |= PTE_ATTRINDX(MT_NORMAL_TAGGED); return __pgprot(prot); @@ -72,4 +74,14 @@ static inline bool arch_validate_prot(unsigned long prot, } #define arch_validate_prot(prot, addr) arch_validate_prot(prot, addr) +static inline bool arch_validate_flags(unsigned long vm_flags) +{ + if (!system_supports_mte()) + return true; + + /* only allow VM_MTE if VM_MTE_ALLOWED has been set previously */ + return !(vm_flags & VM_MTE) || (vm_flags & VM_MTE_ALLOWED); +} +#define arch_validate_flags(vm_flags) arch_validate_flags(vm_flags) + #endif /* ! __ASM_MMAN_H__ */