 static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode)
 {
 	if (file->f_flags & O_DSYNC)
 		return 0;
	if (!nfs_write_pageuptodate(page, inode))
		return 0;
 	if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
 		return 1;
	if (inode->i_flock == NULL || (inode->i_flock->fl_start == 0 &&
 			inode->i_flock->fl_end == OFFSET_MAX &&
			inode->i_flock->fl_type != F_RDLCK))
 		return 1;
 	return 0;
 }

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.