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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 01D10C4332F for ; Mon, 2 May 2022 08:20:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344335AbiEBIYM (ORCPT ); Mon, 2 May 2022 04:24:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1383745AbiEBIXy (ORCPT ); Mon, 2 May 2022 04:23:54 -0400 Received: from mail105.syd.optusnet.com.au (mail105.syd.optusnet.com.au [211.29.132.249]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 925B86317 for ; Mon, 2 May 2022 01:20:23 -0700 (PDT) Received: from dread.disaster.area (pa49-181-2-147.pa.nsw.optusnet.com.au [49.181.2.147]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 4A44610E666F for ; Mon, 2 May 2022 18:20:22 +1000 (AEST) Received: from discord.disaster.area ([192.168.253.110]) by dread.disaster.area with esmtp (Exim 4.92.3) (envelope-from ) id 1nlRI4-0073Tn-PV for linux-xfs@vger.kernel.org; Mon, 02 May 2022 18:20:20 +1000 Received: from dave by discord.disaster.area with local (Exim 4.95) (envelope-from ) id 1nlRI4-004WML-O7 for linux-xfs@vger.kernel.org; Mon, 02 May 2022 18:20:20 +1000 From: Dave Chinner To: linux-xfs@vger.kernel.org Subject: [PATCH 4/4] xfs: validate v5 feature fields Date: Mon, 2 May 2022 18:20:18 +1000 Message-Id: <20220502082018.1076561-5-david@fromorbit.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220502082018.1076561-1-david@fromorbit.com> References: <20220502082018.1076561-1-david@fromorbit.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.4 cv=e9dl9Yl/ c=1 sm=1 tr=0 ts=626f9446 a=ivVLWpVy4j68lT4lJFbQgw==:117 a=ivVLWpVy4j68lT4lJFbQgw==:17 a=oZkIemNP1mAA:10 a=20KFwNOVAAAA:8 a=YMDFXDUo5hmWN72gFVsA:9 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Dave Chinner Because stupid dumb fuzzers. Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_sb.c | 67 +++++++++++++++++++++++++++++++++++------- 1 file changed, 57 insertions(+), 10 deletions(-) diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c index ec6eec5c0e02..d1afe0d43d7f 100644 --- a/fs/xfs/libxfs/xfs_sb.c +++ b/fs/xfs/libxfs/xfs_sb.c @@ -30,6 +30,46 @@ * Physical superblock buffer manipulations. Shared with libxfs in userspace. */ +/* + * Validate all the compulsory V4 feature bits are set on a V5 filesystem. + */ +bool +xfs_sb_validate_v5_features( + struct xfs_sb *sbp) +{ + /* We must not have any unknown V4 feature bits set */ + if (sbp->sb_versionnum & ~XFS_SB_VERSION_OKBITS) + return false; + + /* + * The CRC bit is considered an invalid V4 flag, so we have to add it + * manually to the OKBITS mask. + */ + if (sbp->sb_features2 & ~(XFS_SB_VERSION2_OKBITS | + XFS_SB_VERSION2_CRCBIT)) + return false; + + /* Now check all the required V4 feature flags are set. */ + +#define V5_VERS_FLAGS (XFS_SB_VERSION_NLINKBIT | \ + XFS_SB_VERSION_ALIGNBIT | \ + XFS_SB_VERSION_LOGV2BIT | \ + XFS_SB_VERSION_EXTFLGBIT | \ + XFS_SB_VERSION_DIRV2BIT | \ + XFS_SB_VERSION_MOREBITSBIT) + +#define V5_FEAT_FLAGS (XFS_SB_VERSION2_LAZYSBCOUNTBIT | \ + XFS_SB_VERSION2_ATTR2BIT | \ + XFS_SB_VERSION2_PROJID32BIT | \ + XFS_SB_VERSION2_CRCBIT) + + if ((sbp->sb_versionnum & V5_VERS_FLAGS) != V5_VERS_FLAGS) + return false; + if ((sbp->sb_features2 & V5_FEAT_FLAGS) != V5_FEAT_FLAGS) + return false; + return true; +} + /* * We support all XFS versions newer than a v4 superblock with V2 directories. */ @@ -37,9 +77,19 @@ bool xfs_sb_good_version( struct xfs_sb *sbp) { - /* all v5 filesystems are supported */ + /* + * All v5 filesystems are supported, but we must check that all the + * required v4 feature flags are enabled correctly as the code checks + * those flags and not for v5 support. + */ if (xfs_sb_is_v5(sbp)) - return true; + return xfs_sb_validate_v5_features(sbp); + + /* We must not have any unknown v4 feature bits set */ + if ((sbp->sb_versionnum & ~XFS_SB_VERSION_OKBITS) || + ((sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT) && + (sbp->sb_features2 & ~XFS_SB_VERSION2_OKBITS))) + return false; /* versions prior to v4 are not supported */ if (XFS_SB_VERSION_NUM(sbp) < XFS_SB_VERSION_4) @@ -51,12 +101,6 @@ xfs_sb_good_version( if (!(sbp->sb_versionnum & XFS_SB_VERSION_EXTFLGBIT)) return false; - /* And must not have any unknown v4 feature bits set */ - if ((sbp->sb_versionnum & ~XFS_SB_VERSION_OKBITS) || - ((sbp->sb_versionnum & XFS_SB_VERSION_MOREBITSBIT) && - (sbp->sb_features2 & ~XFS_SB_VERSION2_OKBITS))) - return false; - /* It's a supported v4 filesystem */ return true; } @@ -267,12 +311,15 @@ xfs_validate_sb_common( bool has_dalign; if (!xfs_verify_magic(bp, dsb->sb_magicnum)) { - xfs_warn(mp, "bad magic number"); + xfs_warn(mp, +"Superblock has bad magic number 0x%x. Not an XFS filesystem?", + be32_to_cpu(dsb->sb_magicnum)); return -EWRONGFS; } if (!xfs_sb_good_version(sbp)) { - xfs_warn(mp, "bad version"); + xfs_warn(mp, +"Superblock has unknown features enabled or corrupted feature masks."); return -EWRONGFS; } -- 2.35.1