[PATCH] xfs: add more checks to superblock validation

[Felix Blyakher <felixb@xxxxxxx>]

From: Olaf Weber <olaf@xxxxxxx>

There had been reports where xfs filesystem was randomly
corrupted with fsfuzzer, and xfs failed to handle it
gracefully. This patch fixes couple of reported problem
by providing additional checks in the superblock
validation routine.

Signed-off-by: Felix Blyakher <felixb@xxxxxxx>
---
 fs/xfs/xfs_mount.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index b101990..65a9972 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -291,14 +291,17 @@ xfs_mount_validate_sb(
            sbp->sb_sectsize > XFS_MAX_SECTORSIZE                       ||
            sbp->sb_sectlog < XFS_MIN_SECTORSIZE_LOG                    ||
            sbp->sb_sectlog > XFS_MAX_SECTORSIZE_LOG                    ||
+           sbp->sb_sectsize != (1 << sbp->sb_sectlog)                  ||
            sbp->sb_blocksize < XFS_MIN_BLOCKSIZE                       ||
            sbp->sb_blocksize > XFS_MAX_BLOCKSIZE                       ||
            sbp->sb_blocklog < XFS_MIN_BLOCKSIZE_LOG                    ||
            sbp->sb_blocklog > XFS_MAX_BLOCKSIZE_LOG                    ||
+           sbp->sb_blocksize != (1 << sbp->sb_blocklog)                ||
            sbp->sb_inodesize < XFS_DINODE_MIN_SIZE                     ||
            sbp->sb_inodesize > XFS_DINODE_MAX_SIZE                     ||
            sbp->sb_inodelog < XFS_DINODE_MIN_LOG                       ||
            sbp->sb_inodelog > XFS_DINODE_MAX_LOG                       ||
+           sbp->sb_inodesize != (1 << sbp->sb_inodelog)                ||
            (sbp->sb_blocklog - sbp->sb_inodelog != sbp->sb_inopblog)   ||
            (sbp->sb_rextsize * sbp->sb_blocksize > XFS_MAX_RTEXTSIZE)  ||
            (sbp->sb_rextsize * sbp->sb_blocksize < XFS_MIN_RTEXTSIZE)  ||
-- 
1.5.4.rc3