smb: client: fix reparse buffer bounds in cifs_query_reparse_point()

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix reparse buffer bounds in cifs_query_reparse_point() In cifs_query_reparse_point(), the start >= end check before casting to struct reparse_data_buffer * only ensures the start pointer is within the response. It fails to verify that there is enough space remaining for the fixed 8-byte header of the structure. If a server provides a DataOffset that leaves less than 8 bytes remaining, the check passes, but subsequent reads of ReparseTag and ReparseDataLength will occur out-of-bounds. Fix this by ensuring the remaining space is at least the size of the reparse_data_buffer structure before accessing its fields.

Where it's fixed