[Bug-tar] Problem restoring files that have filenames exactly 512 chars (inc null term).

[sa]

I have noticed a problem restoring files
where there filename plus the null terminator = 512 characters. The problem
appears to be in the calculation of the number of blocks required to store
the LongLink information.

The source code I have is for tar 1.15.1.
I believe the problem is in the list.c - read_header function.

The code from line  377

         
else if (header->header.typeflag == GNUTYPE_LONGNAME
         
         || header->header.typeflag
== GNUTYPE_LONGLINK)
         
  {
         
    size_t name_size = current_stat_info.stat.st_size;
         
    size = name_size - name_size % BLOCKSIZE + 2 * BLOCKSIZE;
         
    if (name_size != current_stat_info.stat.st_size
         
        || size < name_size)
         
      xalloc_die ();

For files with a filename length of
exactly 512 characters, and multiples of, the size is calculated as 1536
causing the read to require an extra null block after the name data. This
I believe is incorrect and should only be 1024 as calculated in the write_gnu_long_link
function in create.c

Regards,

Steve.

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