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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 39E3FC07E85 for ; Sun, 9 Dec 2018 22:14:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 08E5C20661 for ; Sun, 9 Dec 2018 22:14:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 08E5C20661 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728109AbeLIWOO (ORCPT ); Sun, 9 Dec 2018 17:14:14 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:38036 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728507AbeLIWOL (ORCPT ); Sun, 9 Dec 2018 17:14:11 -0500 Received: from pub.yeoldevic.com ([81.174.156.145] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gW73B-0002iY-Vb; Sun, 09 Dec 2018 21:55:46 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gW72e-0003QG-5T; Sun, 09 Dec 2018 21:55:12 +0000 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, "Jeremy Cline" , "Josh Poimboeuf" , "Jan Kara" Date: Sun, 09 Dec 2018 21:50:33 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 154/328] fs/quota: Fix spectre gadget in do_quotactl In-Reply-To: X-SA-Exim-Connect-IP: 81.174.156.145 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.62-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Jeremy Cline commit 7b6924d94a60c6b8c1279ca003e8744e6cd9e8b1 upstream. 'type' is user-controlled, so sanitize it after the bounds check to avoid using it in speculative execution. This covers the following potential gadgets detected with the help of smatch: * fs/ext4/super.c:5741 ext4_quota_read() warn: potential spectre issue 'sb_dqopt(sb)->files' [r] * fs/ext4/super.c:5778 ext4_quota_write() warn: potential spectre issue 'sb_dqopt(sb)->files' [r] * fs/f2fs/super.c:1552 f2fs_quota_read() warn: potential spectre issue 'sb_dqopt(sb)->files' [r] * fs/f2fs/super.c:1608 f2fs_quota_write() warn: potential spectre issue 'sb_dqopt(sb)->files' [r] * fs/quota/dquot.c:412 mark_info_dirty() warn: potential spectre issue 'sb_dqopt(sb)->info' [w] * fs/quota/dquot.c:933 dqinit_needed() warn: potential spectre issue 'dquots' [r] * fs/quota/dquot.c:2112 dquot_commit_info() warn: potential spectre issue 'dqopt->ops' [r] * fs/quota/dquot.c:2362 vfs_load_quota_inode() warn: potential spectre issue 'dqopt->files' [w] (local cap) * fs/quota/dquot.c:2369 vfs_load_quota_inode() warn: potential spectre issue 'dqopt->ops' [w] (local cap) * fs/quota/dquot.c:2370 vfs_load_quota_inode() warn: potential spectre issue 'dqopt->info' [w] (local cap) * fs/quota/quota.c:110 quota_getfmt() warn: potential spectre issue 'sb_dqopt(sb)->info' [r] * fs/quota/quota_v2.c:84 v2_check_quota_file() warn: potential spectre issue 'quota_magics' [w] * fs/quota/quota_v2.c:85 v2_check_quota_file() warn: potential spectre issue 'quota_versions' [w] * fs/quota/quota_v2.c:96 v2_read_file_info() warn: potential spectre issue 'dqopt->info' [r] * fs/quota/quota_v2.c:172 v2_write_file_info() warn: potential spectre issue 'dqopt->info' [r] Additionally, a quick inspection indicates there are array accesses with 'type' in quota_on() and quota_off() functions which are also addressed by this. Cc: Josh Poimboeuf Signed-off-by: Jeremy Cline Signed-off-by: Jan Kara [bwh: Backported to 3.16: The maximum valid quota type is command-dependent. Introduce a local variable rather than repeating the expression.] Signed-off-by: Ben Hutchings --- --- a/fs/quota/quota.c +++ b/fs/quota/quota.c @@ -17,6 +17,7 @@ #include #include #include +#include static int check_quotactl_permission(struct super_block *sb, int type, int cmd, qid_t id) @@ -405,10 +406,12 @@ static int quota_rmxquota(struct super_b static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, void __user *addr, struct path *path) { + unsigned int max_quotas = XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS; int ret; - if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS)) + if (type >= max_quotas) return -EINVAL; + type = array_index_nospec(type, max_quotas); if (!sb->s_qcop) return -ENOSYS;