xfs: initialize the shortform attr header padding entry

[ Upstream commit 125eac24 ]

Don't leak kernel memory contents into the shortform attr fork.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/xfs/libxfs/xfs_attr_leaf.c

@@ -520,8 +520,8 @@ xfs_attr_shortform_create(xfs_da_args_t *args)
 		ASSERT(ifp->if_flags & XFS_IFINLINE);
 	}
 	xfs_idata_realloc(dp, sizeof(*hdr), XFS_ATTR_FORK);
-	hdr = (xfs_attr_sf_hdr_t *)ifp->if_u1.if_data;
-	hdr->count = 0;
+	hdr = (struct xfs_attr_sf_hdr *)ifp->if_u1.if_data;
+	memset(hdr, 0, sizeof(*hdr));
 	hdr->totsize = cpu_to_be16(sizeof(*hdr));
 	xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_ADATA);
 }