xfs: sanity check inode di_mode

commit a324cbf1 upstream.

Check for invalid file type in xfs_dinode_verify()
and fail to load the inode structure from disk.
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

fs/xfs/libxfs/xfs_inode_buf.c

@@ -29,6 +29,7 @@
 #include "xfs_icache.h"
 #include "xfs_trans.h"
 #include "xfs_ialloc.h"
+#include "xfs_dir2.h"
 
 /*
  * Check that none of the inode's in the buffer have a next
@@ -398,6 +399,8 @@ xfs_dinode_verify(
 		return false;
 
 	mode = be16_to_cpu(dip->di_mode);
+	if (mode && xfs_mode_to_ftype(mode) == XFS_DIR3_FT_UNKNOWN)
+		return false;
 
 	/* No zero-length symlinks/dirs. */
 	if ((S_ISLNK(mode) || S_ISDIR(mode)) && dip->di_size == 0)