From patchwork Fri Jun 17 20:00:39 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Lutomirski X-Patchwork-Id: 9184837 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id D29B66075D for ; Fri, 17 Jun 2016 20:01:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AA7FE27DF9 for ; Fri, 17 Jun 2016 20:01:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 9F0B0280B0; Fri, 17 Jun 2016 20:01:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 2680427DF9 for ; Fri, 17 Jun 2016 20:01:34 +0000 (UTC) Received: (qmail 26356 invoked by uid 550); 17 Jun 2016 20:01:11 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Reply-To: kernel-hardening@lists.openwall.com Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 26287 invoked from network); 17 Jun 2016 20:01:09 -0000 From: Andy Lutomirski To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, Borislav Petkov , Nadav Amit , Kees Cook , Brian Gerst , "kernel-hardening@lists.openwall.com" , Linus Torvalds , Josh Poimboeuf , Jann Horn , Heiko Carstens , Andy Lutomirski Date: Fri, 17 Jun 2016 13:00:39 -0700 Message-Id: <3336bb02792d56c49d18e2f7a435fd194a4a22e4.1466192946.git.luto@kernel.org> X-Mailer: git-send-email 2.5.5 In-Reply-To: References: In-Reply-To: References: X-Virus-Scanned: ClamAV using ClamSMTP Subject: [kernel-hardening] [PATCH v2 03/13] x86/cpa: Warn if kernel_unmap_pages_in_pgd is used inappropriately X-Virus-Scanned: ClamAV using ClamSMTP It's currently only used in the EFI code, which is safe AFAICT. Warn if anyone tries to use it on the normal kernel pgd. Signed-off-by: Andy Lutomirski --- arch/x86/mm/pageattr.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 6a8026918bf6..e9b9c5cedbb8 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -1996,6 +1996,9 @@ out: void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address, unsigned numpages) { + /* Unmapping kernel entries from init_mm's pgd is not allowed. */ + WARN_ON(root == init_mm.pgd); + unmap_pgd_range(root, address, address + (numpages << PAGE_SHIFT)); }