fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot

In the Linux kernel, the following vulnerability has been resolved:

fs/ntfs3: Fix slab-out-of-bounds read in DeleteIndexEntryRoot

In the 'DeleteIndexEntryRoot' case of the 'do_action' function, the

entry size ('esize') is retrieved from the log record without adequate

bounds checking.

Specifically, the code calculates the end of the entry ('e2') using:

e2 = Add2Ptr(e1, esize);

It then calculates the size for memmove using 'PtrOffset(e2, ...)',

which subtracts the end pointer from the buffer limit. If 'esize' is

maliciously large, 'e2' exceeds the used buffer size. This results in

a negative offset which, when cast to size_t for memmove, interprets

as a massive unsigned integer, leading to a heap buffer overflow.

This commit adds a check to ensure that the entry size ('esize') strictly

fits within the remaining used space of the index header before performing

memory operations.