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Commit 9e037cb7 authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: check for unknown v5 feature bits in superblock write verifier 



Make sure we never try to write the superblock with unknown feature bits
set.  We checked those at mount time, so if they're set now then memory
is corrupt.

Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarEric Sandeen <sandeen@redhat.com>
parent 69775fd1

fs/xfs/libxfs/xfs_sb.c

+34 −1
Original line number Diff line number Diff line
@@ -166,7 +166,40 @@ xfs_validate_sb_write( 
	if (XFS_SB_VERSION_NUM(sbp) != XFS_SB_VERSION_5)

		return 0;



	/* XXX: For write validation, we don't need to check feature masks?? */

	/*

	 * Version 5 superblock feature mask validation. Reject combinations

	 * the kernel cannot support since we checked for unsupported bits in

	 * the read verifier, which means that memory is corrupt.

	 */

	if (xfs_sb_has_compat_feature(sbp, XFS_SB_FEAT_COMPAT_UNKNOWN)) {

		xfs_warn(mp,

"Corruption detected in superblock compatible features (0x%x)!",

			(sbp->sb_features_compat & XFS_SB_FEAT_COMPAT_UNKNOWN));

		return -EFSCORRUPTED;

	}



	if (xfs_sb_has_ro_compat_feature(sbp, XFS_SB_FEAT_RO_COMPAT_UNKNOWN)) {

		xfs_alert(mp,

"Corruption detected in superblock read-only compatible features (0x%x)!",

			(sbp->sb_features_ro_compat &

					XFS_SB_FEAT_RO_COMPAT_UNKNOWN));

		return -EFSCORRUPTED;

	}

	if (xfs_sb_has_incompat_feature(sbp, XFS_SB_FEAT_INCOMPAT_UNKNOWN)) {

		xfs_warn(mp,

"Corruption detected in superblock incompatible features (0x%x)!",

			(sbp->sb_features_incompat &

					XFS_SB_FEAT_INCOMPAT_UNKNOWN));

		return -EFSCORRUPTED;

	}

	if (xfs_sb_has_incompat_log_feature(sbp,

			XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN)) {

		xfs_warn(mp,

"Corruption detected in superblock incompatible log features (0x%x)!",

			(sbp->sb_features_log_incompat &

					XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN));

		return -EFSCORRUPTED;

	}



	/*

	 * We can't read verify the sb LSN because the read verifier is called