From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sandeen.net ([63.231.237.45]:35344 "EHLO sandeen.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752424AbdAZBR6 (ORCPT ); Wed, 25 Jan 2017 20:17:58 -0500 Subject: [PATCH v10 1/5] xfs_db: sanitize agcount on load References: <148494391629.5256.3328772079712970611.stgit@birch.djwong.org> <148494392247.5256.10692618169002348643.stgit@birch.djwong.org> <20170123213108.GD31202@birch.djwong.org> <6ad3798a-c3f5-fd8f-ab05-62c0f878290c@sandeen.net> <17bbf8d4-39f7-a542-6c9d-3cd96e865ddf@sandeen.net> <886473a5-c0ff-a5b7-38bc-13d4d5d13c3c@sandeen.net> From: Eric Sandeen Message-ID: Date: Wed, 25 Jan 2017 19:17:56 -0600 MIME-Version: 1.0 In-Reply-To: <886473a5-c0ff-a5b7-38bc-13d4d5d13c3c@sandeen.net> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: "Darrick J. Wong" , sandeen@redhat.com Cc: linux-xfs@vger.kernel.org Before we get into libxfs_initialize_perag and try to blindly allocate a perag struct for every (possibly corrupted number of) AGs, see if we can read the last one. If not, assume it's corrupt, and load only the first AG. Do this only for an arbitrarily high-ish agcount, so that normal-ish geometry on a possibly truncated file or device will still do its best to make all readable AGs available. Set xfs_db's exitcode to 1 if this happens. Also teach metadump to detect this and exit appropriately if truncated, as it resets exitcode to 0 for its own purposes internally. Signed-off-by: Eric Sandeen --- v1->v6: Tale of woe. v7: blow it all up v8: use bare libxfs_readbuf so verifiers don't matter, "ours goes to 1 million!" v9: Fix printf format, exit metadump with error if things look wonky. v10: set exitcode to 1 in init(). diff --git a/db/init.c b/db/init.c index ec1e274..59fc3e0 100644 --- a/db/init.c +++ b/db/init.c @@ -58,6 +58,7 @@ init( { struct xfs_sb *sbp; struct xfs_buf *bp; + unsigned int agcount; int c; setlocale(LC_ALL, ""); @@ -148,6 +149,7 @@ init( } } + agcount = sbp->sb_agcount; mp = libxfs_mount(&xmount, sbp, x.ddev, x.logdev, x.rtdev, LIBXFS_MOUNT_DEBUGGER); if (!mp) { @@ -159,6 +161,10 @@ init( mp->m_log = &xlog; blkbb = 1 << mp->m_blkbb_log; + /* Did we limit a broken agcount in libxfs_mount? */ + if (sbp->sb_agcount != agcount) + exitcode = 1; + /* * xfs_check needs corrected incore superblock values */ diff --git a/db/metadump.c b/db/metadump.c index 1ba6b38..38519f1 100644 --- a/db/metadump.c +++ b/db/metadump.c @@ -2760,6 +2760,16 @@ metadump_f( return 0; } + /* + * on load, we sanity-checked agcount and possibly set to 1 + * if it was corrupted and large. + */ + if (mp->m_sb.sb_agcount == 1 && + XFS_MAX_DBLOCKS(&mp->m_sb) < mp->m_sb.sb_dblocks) { + print_warning("truncated agcount, giving up"); + return 0; + } + while ((c = getopt(argc, argv, "aegm:ow")) != EOF) { switch (c) { case 'a': diff --git a/libxfs/init.c b/libxfs/init.c index a08575a..85e0d15 100644 --- a/libxfs/init.c +++ b/libxfs/init.c @@ -817,6 +817,29 @@ libxfs_mount( return NULL; } + /* + * libxfs_initialize_perag will allocate a perag structure for each ag. + * If agcount is corrupted and insanely high, this will OOM the box. + * If the agount seems (arbitrarily) high, try to read what would be + * the last AG, and if that fails for a relatively high agcount, just + * read the first one and let the user know to check the geometry. + */ + if (sbp->sb_agcount > 1000000) { + bp = libxfs_readbuf(mp->m_dev, + XFS_AG_DADDR(mp, sbp->sb_agcount - 1, 0), 1, + !(flags & LIBXFS_MOUNT_DEBUGGER), NULL); + if (bp->b_error) { + fprintf(stderr, _("%s: read of AG %u failed\n"), + progname, sbp->sb_agcount); + if (!(flags & LIBXFS_MOUNT_DEBUGGER)) + return NULL; + fprintf(stderr, _("%s: limiting reads to AG 0\n"), + progname); + sbp->sb_agcount = 1; + } + libxfs_putbuf(bp); + } + error = libxfs_initialize_perag(mp, sbp->sb_agcount, &mp->m_maxagi); if (error) { fprintf(stderr, _("%s: perag init failed\n"),