From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1431546-1518324426-2-374780316531690611 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='uk', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1518324425; b=MYO6APSvhRNyeZY/UDOOhRsN7gr70IYTF2C7T4xl2octdVQ 7FG/KfrB48dXHGeeoOPTSWucGL9VPRgaR7PDg7ch2KPIVvs0W3vEHpxZL2s3DeOe eMWbe5btI575KLpVq28rqkK//ykJxGwshOg8qwjxjkNgUSAAy2Ti4yjpgjaYLVwz pHKpA4QAdsu+j9AeWzkQdKKWHhr6pplLZB51L9n534kTmDRwyLxWlN0HxA3H6s6v EhW2WZ+NeV5fO00/v+pyaj6VmChOo6nVwSIV8cBEyPqfIPcGev21HAPIhbNEIchI PMPTfkrxIxcJjU2HFfvXEnZzH0VgE68qacQmxeA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1518324425; bh=N7IDqcmr5QT30VatQmi vXet/0Urb3ZvN5XtNRG6GbJY=; b=TdLKvFaaJAhs22E3KxiRQwhogEpSZn34+Fk nAhbQnXMXOhf1ANWxwMg7QVtb2h9wdH4hcBDZFuNBlQtwultZToEoUs160PWfq5o ukTxPg/CaCV+Yl5u79CBGjMi/9aMbP1qdVSq3EfCD6r/3+S1LrJdZ2xlPUFfmPyJ 3FOdc69x93xAvDQjTyu8D/pE0WfgID37AAhTo9QihEm12snWF7McBr0+fSKk7rH+ MoFzlqUgxgFDVCOd31MS7UmBi0l8892Lum5i5WklhZr9GjIQSx13QJ/PTeRoqvVs kkzqy0nMyXQ3/mbTbYrKse5FJSPbz91ZvrQCk9rO/TdBlqQBUhg== ARC-Authentication-Results: i=1; mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753085AbeBKEpO (ORCPT ); Sat, 10 Feb 2018 23:45:14 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41848 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752854AbeBKEd6 (ORCPT ); Sat, 10 Feb 2018 23:33:58 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Neil Dick" , "Russell King" , "Philip Derrin" , "Kees Cook" Date: Sun, 11 Feb 2018 04:31:11 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 102/136] ARM: 8721/1: mm: dump: check hardware RO bit for LPAE In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.16.54-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Philip Derrin commit 3b0c0c922ff4be275a8beb87ce5657d16f355b54 upstream. When CONFIG_ARM_LPAE is set, the PMD dump relies on the software read-only bit to determine whether a page is writable. This concealed a bug which left the kernel text section writable (AP2=0) while marked read-only in the software bit. In a kernel with the AP2 bug, the dump looks like this: ---[ Kernel Mapping ]--- 0xc0000000-0xc0200000 2M RW NX SHD 0xc0200000-0xc0600000 4M ro x SHD 0xc0600000-0xc0800000 2M ro NX SHD 0xc0800000-0xc4800000 64M RW NX SHD The fix is to check that the software and hardware bits are both set before displaying "ro". The dump then shows the true perms: ---[ Kernel Mapping ]--- 0xc0000000-0xc0200000 2M RW NX SHD 0xc0200000-0xc0600000 4M RW x SHD 0xc0600000-0xc0800000 2M RW NX SHD 0xc0800000-0xc4800000 64M RW NX SHD Fixes: ded947798469 ("ARM: 8109/1: mm: Modify pte_write and pmd_write logic for LPAE") Signed-off-by: Philip Derrin Tested-by: Neil Dick Reviewed-by: Kees Cook Signed-off-by: Russell King Signed-off-by: Ben Hutchings --- arch/arm/mm/dump.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/arch/arm/mm/dump.c +++ b/arch/arm/mm/dump.c @@ -126,8 +126,8 @@ static const struct prot_bits section_bi .val = PMD_SECT_USER, .set = "USR", }, { - .mask = L_PMD_SECT_RDONLY, - .val = L_PMD_SECT_RDONLY, + .mask = L_PMD_SECT_RDONLY | PMD_SECT_AP2, + .val = L_PMD_SECT_RDONLY | PMD_SECT_AP2, .set = "ro", .clear = "RW", #elif __LINUX_ARM_ARCH__ >= 6