ntfs: detect mapping-pairs LCN accumulator overflow

In the Linux kernel, the following vulnerability has been resolved: ntfs: detect mapping-pairs LCN accumulator overflow The NTFS mapping-pairs parser accumulates relative LCN deltas in a signed integer. A corrupted attribute can drive that addition past the representable range. One corrupt runlist shape sets the accumulated LCN to S64_MAX and then adds a delta of 1 in the next mapping-pairs entry. Signed overflow is undefined and can turn an invalid runlist into a different set of physical clusters. Check the LCN addition for overflow before storing the next run.