ntfs: check overflow when iterating ATTR_RECORDs

In the Linux kernel, the following vulnerability has been resolved: ntfs: check overflow when iterating ATTR_RECORDs Kernel iterates over ATTR_RECORDs in mft record in ntfs_attr_find(). Because the ATTR_RECORDs are next to each other, kernel can get the next ATTR_RECORD from end address of current ATTR_RECORD, through current ATTR_RECORD length field. The problem is that during iteration, when kernel calculates the end address of current ATTR_RECORD, kernel may trigger an integer overflow bug in executing `a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))`. This may wrap, leading to a forever iteration on 32bit systems. This patch solves it by adding some checks on calculating end address of current ATTR_RECORD during iteration.