bug#25149: md5sum fails with message "Invalid argument" on 4, 294, 967, 295-byte files in FAT32

[Jaime Gaspar]

--- Bug ---
In a FAT32 file system, if one runs md5sum on a 4,294,967,294-byte file (one 
byte less than the maximum file size) it succeeds, but if one runs md5sum on a 
4,294,967,295-byte file (the maximum file size) it fails with error message 
"Invalid argument".

--- How to reproduce the bug ---
Create a FAT32 file system in a file "tmp.fs":
   truncate -s 9G tmp.fs
   mkfs.vfat -F 32 tmp.fs
Mount at "/tmp/mounted_tmp/" the file system in file "tmp.fs":
   sudo mkdir /tmp/mounted_tmp/
   sudo mount -o loop,rw,uid=1000,gid=1000 tmp.fs /tmp/mounted_tmp/
Create two files in "/tmp/mounted_tmp/", file "file_1" with 4,294,967,294 bytes 
and file "file_2" with 4,294,967,295 bytes:
   cd /tmp/mounted_tmp/
   truncate -s 4294967294 file_1
   truncate -s 4294967295 file_2
Run md5sum on the two files "file_1" and "file_2":
   md5sum file_1
   md5sum file_2
The outputs should be respectively (notice that the second output is an error 
message):
   541249e3205af07b4a03f891185f64a0  file_1
   md5sum: file_2: Invalid argument
Unmount the file system at "/tmp/mounted_tmp/":
   cd ..
   sudo umount /tmp/mounted_tmp/
   sudo rmdir /tmp/mounted_tmp/
Remove the file "tmp.fs".

--- Notes ---
Tested with md5sum 8.25 running on an updated Ubuntu 16.10 with kernel 
4.8.0-30-generic.
The same bug affects sha1sum, sha224sum, sha256sum, sha384sum, and sha512sum, 
but not crc32.