From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98790C433E2 for ; Fri, 4 Sep 2020 10:33:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68BC6206D4 for ; Fri, 4 Sep 2020 10:33:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730117AbgIDKcy (ORCPT ); Fri, 4 Sep 2020 06:32:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:51528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729946AbgIDKbV (ORCPT ); Fri, 4 Sep 2020 06:31:21 -0400 Received: from localhost.localdomain (unknown [46.69.195.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 88B412084D; Fri, 4 Sep 2020 10:31:07 +0000 (UTC) From: Catalin Marinas 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 Subject: [PATCH v9 15/29] mm: Introduce arch_validate_flags() Date: Fri, 4 Sep 2020 11:30:15 +0100 Message-Id: <20200904103029.32083-16-catalin.marinas@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200904103029.32083-1-catalin.marinas@arm.com> References: <20200904103029.32083-1-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org Similarly to arch_validate_prot() called from do_mprotect_pkey(), an architecture may need to sanity-check the new vm_flags. Define a dummy function always returning true. In addition to do_mprotect_pkey(), also invoke it from mmap_region() prior to updating vma->vm_page_prot to allow the architecture code to veto potentially inconsistent vm_flags. Signed-off-by: Catalin Marinas Acked-by: Andrew Morton --- Notes: v2: - Some comments updated. include/linux/mman.h | 13 +++++++++++++ mm/mmap.c | 9 +++++++++ mm/mprotect.c | 6 ++++++ 3 files changed, 28 insertions(+) diff --git a/include/linux/mman.h b/include/linux/mman.h index 6fa15c9b12af..629cefc4ecba 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -108,6 +108,19 @@ static inline bool arch_validate_prot(unsigned long prot, unsigned long addr) #define arch_validate_prot arch_validate_prot #endif +#ifndef arch_validate_flags +/* + * This is called from mmap() and mprotect() with the updated vma->vm_flags. + * + * Returns true if the VM_* flags are valid. + */ +static inline bool arch_validate_flags(unsigned long flags) +{ + return true; +} +#define arch_validate_flags arch_validate_flags +#endif + /* * Optimisation macro. It is equivalent to: * (x & bit1) ? bit2 : 0 diff --git a/mm/mmap.c b/mm/mmap.c index 40248d84ad5f..eed30b096667 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1812,6 +1812,15 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vma_set_anonymous(vma); } + /* Allow architectures to sanity-check the vm_flags */ + if (!arch_validate_flags(vma->vm_flags)) { + error = -EINVAL; + if (file) + goto unmap_and_free_vma; + else + goto free_vma; + } + vma_link(mm, vma, prev, rb_link, rb_parent); /* Once vma denies write, undo our temporary denial count */ if (file) { diff --git a/mm/mprotect.c b/mm/mprotect.c index ce8b8a5eacbb..56c02beb6041 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -603,6 +603,12 @@ static int do_mprotect_pkey(unsigned long start, size_t len, goto out; } + /* Allow architectures to sanity-check the new flags */ + if (!arch_validate_flags(newflags)) { + error = -EINVAL; + goto out; + } + error = security_file_mprotect(vma, reqprot, prot); if (error) goto out;