Patch "xfs: verify free block header fields" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    xfs: verify free block header fields

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     xfs-verify-free-block-header-fields.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From de14c5f541e78c59006bee56f6c5c2ef1ca07272 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Thu, 2 Feb 2017 15:14:00 -0800
Subject: xfs: verify free block header fields

From: Darrick J. Wong <darrick.wong@oracle.com>

commit de14c5f541e78c59006bee56f6c5c2ef1ca07272 upstream.

Perform basic sanity checking of the directory free block header
fields so that we avoid hanging the system on invalid data.

(Granted that just means that now we shutdown on directory write,
but that seems better than hanging...)

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/xfs/libxfs/xfs_dir2_node.c |   51 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 49 insertions(+), 2 deletions(-)

--- a/fs/xfs/libxfs/xfs_dir2_node.c
+++ b/fs/xfs/libxfs/xfs_dir2_node.c
@@ -155,6 +155,42 @@ const struct xfs_buf_ops xfs_dir3_free_b
 	.verify_write = xfs_dir3_free_write_verify,
 };
 
+/* Everything ok in the free block header? */
+static bool
+xfs_dir3_free_header_check(
+	struct xfs_inode	*dp,
+	xfs_dablk_t		fbno,
+	struct xfs_buf		*bp)
+{
+	struct xfs_mount	*mp = dp->i_mount;
+	unsigned int		firstdb;
+	int			maxbests;
+
+	maxbests = dp->d_ops->free_max_bests(mp->m_dir_geo);
+	firstdb = (xfs_dir2_da_to_db(mp->m_dir_geo, fbno) -
+		   xfs_dir2_byte_to_db(mp->m_dir_geo, XFS_DIR2_FREE_OFFSET)) *
+			maxbests;
+	if (xfs_sb_version_hascrc(&mp->m_sb)) {
+		struct xfs_dir3_free_hdr *hdr3 = bp->b_addr;
+
+		if (be32_to_cpu(hdr3->firstdb) != firstdb)
+			return false;
+		if (be32_to_cpu(hdr3->nvalid) > maxbests)
+			return false;
+		if (be32_to_cpu(hdr3->nvalid) < be32_to_cpu(hdr3->nused))
+			return false;
+	} else {
+		struct xfs_dir2_free_hdr *hdr = bp->b_addr;
+
+		if (be32_to_cpu(hdr->firstdb) != firstdb)
+			return false;
+		if (be32_to_cpu(hdr->nvalid) > maxbests)
+			return false;
+		if (be32_to_cpu(hdr->nvalid) < be32_to_cpu(hdr->nused))
+			return false;
+	}
+	return true;
+}
 
 static int
 __xfs_dir3_free_read(
@@ -168,11 +204,22 @@ __xfs_dir3_free_read(
 
 	err = xfs_da_read_buf(tp, dp, fbno, mappedbno, bpp,
 				XFS_DATA_FORK, &xfs_dir3_free_buf_ops);
+	if (err || !*bpp)
+		return err;
+
+	/* Check things that we can't do in the verifier. */
+	if (!xfs_dir3_free_header_check(dp, fbno, *bpp)) {
+		xfs_buf_ioerror(*bpp, -EFSCORRUPTED);
+		xfs_verifier_error(*bpp);
+		xfs_trans_brelse(tp, *bpp);
+		return -EFSCORRUPTED;
+	}
 
 	/* try read returns without an error or *bpp if it lands in a hole */
-	if (!err && tp && *bpp)
+	if (tp)
 		xfs_trans_buf_set_type(tp, *bpp, XFS_BLFT_DIR_FREE_BUF);
-	return err;
+
+	return 0;
 }
 
 int


Patches currently in stable-queue which might be from darrick.wong@oracle.com are

queue-4.9/xfs-mark-speculative-prealloc-cow-fork-extents-unwritten.patch
queue-4.9/xfs-fix-toctou-race-when-locking-an-inode-to-access-the-data-map.patch
queue-4.9/xfs-use-iomap-new-flag-for-newly-allocated-delalloc-blocks.patch
queue-4.9/xfs-handle-indlen-shortage-on-delalloc-extent-merge.patch
queue-4.9/xfs-reject-all-unaligned-direct-writes-to-reflinked-files.patch
queue-4.9/xfs-allow-unwritten-extents-in-the-cow-fork.patch
queue-4.9/xfs-tune-down-agno-asserts-in-the-bmap-code.patch
queue-4.9/xfs-verify-free-block-header-fields.patch
queue-4.9/xfs-check-for-obviously-bad-level-values-in-the-bmbt-root.patch
queue-4.9/xfs-don-t-fail-xfs_extent_busy-allocation.patch
queue-4.9/xfs-sync-eofblocks-scans-under-iolock-are-livelock-prone.patch
queue-4.9/xfs-use-per-ag-reservations-for-the-finobt.patch
queue-4.9/xfs-pull-up-iolock-from-xfs_free_eofblocks.patch
queue-4.9/xfs-fail-_dir_open-when-readahead-fails.patch
queue-4.9/xfs-reset-b_first_retry_time-when-clear-the-retry-status-of-xfs_buf_t.patch
queue-4.9/xfs-update-ctime-and-mtime-on-clone-destinatation-inodes.patch
queue-4.9/xfs-only-update-mount-resv-fields-on-success-in-__xfs_ag_resv_init.patch
queue-4.9/xfs-split-indlen-reservations-fairly-when-under-reserved.patch
queue-4.9/xfs-filter-out-obviously-bad-btree-pointers.patch
queue-4.9/xfs-use-xfs_icluster_size_fsb-to-calculate-inode-chunk-alignment.patch
queue-4.9/xfs-only-reclaim-unwritten-cow-extents-periodically.patch
queue-4.9/xfs-try-any-ag-when-allocating-the-first-btree-block-when-reflinking.patch
queue-4.9/xfs-fix-and-streamline-error-handling-in-xfs_end_io.patch
queue-4.9/xfs-fix-eofblocks-race-with-file-extending-async-dio-writes.patch
queue-4.9/xfs-fix-uninitialized-variable-in-_reflink_convert_cow.patch
queue-4.9/xfs-don-t-reserve-blocks-for-right-shift-transactions.patch
queue-4.9/xfs-use-xfs_icluster_size_fsb-to-calculate-inode-alignment-mask.patch