From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: sandeen@redhat.com, darrick.wong@oracle.com
Cc: linux-xfs@vger.kernel.org
Subject: [PATCH 4/5] xfs_db: sanitize geometry on load
Date: Wed, 11 Jan 2017 19:06:53 -0800 [thread overview]
Message-ID: <148419041340.32674.2646685552269275817.stgit@birch.djwong.org> (raw)
In-Reply-To: <148419038856.32674.6479634718673149751.stgit@birch.djwong.org>
xfs_db doesn't check the filesystem geometry when it's mounting, which
means that garbage agcount values can cause OOMs when we try to allocate
all the per-AG incore metadata. If we see geometry that looks
suspicious, try to derive the actual AG geometry to avoid crashing the
system. This should help with xfs/1301 fuzzing.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
db/init.c | 91 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 81 insertions(+), 10 deletions(-)
diff --git a/db/init.c b/db/init.c
index ec1e274..a394728 100644
--- a/db/init.c
+++ b/db/init.c
@@ -51,13 +51,90 @@ usage(void)
exit(1);
}
+/* Try to load an AG's superblock, no verifiers. */
+static bool
+load_sb(
+ struct xfs_mount *mp,
+ xfs_agnumber_t agno,
+ struct xfs_sb *sbp)
+{
+ struct xfs_buf *bp;
+
+ bp = libxfs_readbuf(mp->m_ddev_targp,
+ XFS_AG_DADDR(mp, agno, XFS_SB_DADDR),
+ 1 << (XFS_MAX_SECTORSIZE_LOG - BBSHIFT), 0, NULL);
+
+ if (!bp || bp->b_error)
+ return false;
+
+ /* copy SB from buffer to in-core, converting architecture as we go */
+ libxfs_sb_from_disk(sbp, XFS_BUF_TO_SBP(bp));
+ libxfs_putbuf(bp);
+ libxfs_purgebuf(bp);
+
+ return true;
+}
+
+/* If the geometry doesn't look sane, try to figure out the real geometry. */
+static void
+sanitize_geometry(
+ struct xfs_mount *mp,
+ struct xfs_sb *sbp)
+{
+ struct xfs_sb sb;
+ xfs_agblock_t agblocks;
+
+ /* If the geometry looks ok, we're done. */
+ if (sbp->sb_blocklog >= XFS_MIN_BLOCKSIZE_LOG &&
+ sbp->sb_blocklog <= XFS_MAX_BLOCKSIZE_LOG &&
+ sbp->sb_blocksize == (1 << sbp->sb_blocklog) &&
+ sbp->sb_dblocks * sbp->sb_blocksize <= x.dsize * x.dbsize &&
+ sbp->sb_dblocks <= XFS_MAX_DBLOCKS(sbp) &&
+ sbp->sb_dblocks >= XFS_MIN_DBLOCKS(sbp))
+ return;
+
+ /* Check blocklog and blocksize */
+ if (sbp->sb_blocklog < XFS_MIN_BLOCKSIZE_LOG ||
+ sbp->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG)
+ sbp->sb_blocklog = libxfs_log2_roundup(sbp->sb_blocksize);
+ if (sbp->sb_blocksize != (1 << sbp->sb_blocklog))
+ sbp->sb_blocksize = (1 << sbp->sb_blocksize);
+
+ /* Clamp dblocks to the size of the device. */
+ if (sbp->sb_dblocks > x.dsize * x.dbsize / sbp->sb_blocksize)
+ sbp->sb_dblocks = x.dsize * x.dbsize / sbp->sb_blocksize;
+
+ /* See if agblocks helps us find a superblock. */
+ mp->m_blkbb_log = sbp->sb_blocklog - BBSHIFT;
+ if (load_sb(mp, 1, &sb) && sb.sb_magicnum == XFS_SB_MAGIC) {
+ sbp->sb_agcount = sbp->sb_dblocks / sbp->sb_agblocks;
+ goto out;
+ }
+
+ /* See if agcount helps us find a superblock. */
+ agblocks = sbp->sb_agblocks;
+ sbp->sb_agblocks = sbp->sb_dblocks / sbp->sb_agcount;
+ if (sbp->sb_agblocks != 0 &&
+ load_sb(mp, 1, &sb) &&
+ sb.sb_magicnum == XFS_SB_MAGIC) {
+ goto out;
+ }
+
+ /* Both are nuts, assume 1 AG. */
+ sbp->sb_agblocks = agblocks;
+ sbp->sb_agcount = 1;
+out:
+ fprintf(stderr,
+ _("%s: device %s AG count is insane. Limiting reads to the first %u AGs.\n"),
+ progname, fsdevice, sbp->sb_agcount);
+}
+
void
init(
int argc,
char **argv)
{
struct xfs_sb *sbp;
- struct xfs_buf *bp;
int c;
setlocale(LC_ALL, "");
@@ -124,20 +201,12 @@ init(
*/
memset(&xmount, 0, sizeof(struct xfs_mount));
libxfs_buftarg_init(&xmount, x.ddev, x.logdev, x.rtdev);
- bp = libxfs_readbuf(xmount.m_ddev_targp, XFS_SB_DADDR,
- 1 << (XFS_MAX_SECTORSIZE_LOG - BBSHIFT), 0, NULL);
-
- if (!bp || bp->b_error) {
+ if (!load_sb(&xmount, 0, &xmount.m_sb)) {
fprintf(stderr, _("%s: %s is invalid (cannot read first 512 "
"bytes)\n"), progname, fsdevice);
exit(1);
}
- /* copy SB from buffer to in-core, converting architecture as we go */
- libxfs_sb_from_disk(&xmount.m_sb, XFS_BUF_TO_SBP(bp));
- libxfs_putbuf(bp);
- libxfs_purgebuf(bp);
-
sbp = &xmount.m_sb;
if (sbp->sb_magicnum != XFS_SB_MAGIC) {
fprintf(stderr, _("%s: %s is not a valid XFS filesystem (unexpected SB magic number 0x%08x)\n"),
@@ -148,6 +217,8 @@ init(
}
}
+ sanitize_geometry(&xmount, sbp);
+
mp = libxfs_mount(&xmount, sbp, x.ddev, x.logdev, x.rtdev,
LIBXFS_MOUNT_DEBUGGER);
if (!mp) {
next prev parent reply other threads:[~2017-01-12 3:06 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-12 3:06 [PATCH 0/5] xfsprogs: misc fixes Darrick J. Wong
2017-01-12 3:06 ` [PATCH 1/5] xfs_io: fix the minimum arguments to the reflink command Darrick J. Wong
2017-01-12 13:53 ` Christoph Hellwig
2017-01-12 3:06 ` [PATCH 2/5] xfs_io: fix some documentation problems Darrick J. Wong
2017-01-12 13:53 ` Christoph Hellwig
2017-01-12 3:06 ` [PATCH 3/5] xfs_io: prefix dedupe command error messages consistently Darrick J. Wong
2017-01-12 13:53 ` Christoph Hellwig
2017-01-12 3:06 ` Darrick J. Wong [this message]
2017-01-12 14:34 ` [PATCH 4/5] xfs_db: sanitize geometry on load Eric Sandeen
2017-01-12 15:09 ` Brian Foster
2017-01-12 20:41 ` Darrick J. Wong
2017-01-12 20:41 ` [PATCH v2 " Darrick J. Wong
2017-01-12 23:20 ` Eric Sandeen
2017-01-13 0:23 ` Darrick J. Wong
2017-01-13 0:32 ` [PATCH v3 " Darrick J. Wong
2017-01-13 13:35 ` Brian Foster
2017-01-14 2:25 ` Eric Sandeen
2017-01-14 3:44 ` Brian Foster
2017-01-14 3:51 ` Eric Sandeen
2017-01-14 12:53 ` Brian Foster
2017-01-14 14:59 ` Eric Sandeen
2017-01-15 14:10 ` Brian Foster
2017-01-12 3:06 ` [PATCH 5/5] xfs_repair: strengthen geometry checks Darrick J. Wong
2017-01-14 2:13 ` Eric Sandeen
2017-01-20 20:06 ` Darrick J. Wong
2017-01-12 19:27 ` [PATCH 6/5] xfs_db: fix the 'source' command when passed as a -c option Darrick J. Wong
2017-01-12 19:34 ` [PATCH 7/5] xfs_repair.8: document dirty log conditions Darrick J. Wong
2017-01-12 19:41 ` Eric Sandeen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=148419041340.32674.2646685552269275817.stgit@birch.djwong.org \
--to=darrick.wong@oracle.com \
--cc=linux-xfs@vger.kernel.org \
--cc=sandeen@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.