Bug #61384 Can't connect MySQL 5.1.57 from old(4.0) clients
Submitted: 2 Jun 2011 11:55 Modified: 2 Jun 2011 12:01
Reporter: Yoshinori Matsunobu (OCA) Email Updates:
Status: Duplicate Impact on me:
Category:MySQL Server: Security: Privileges Severity:S3 (Non-critical)
Version:5.1.57 OS:Any
Assigned to: CPU Architecture:Any

[2 Jun 2011 11:55] Yoshinori Matsunobu
Starting from MySQL 5.1.57, I couldn't connect to mysqld from 
older MySQL clients including MySQL 4.0 and client bindings built from 4.0 libmysqlclient.

How to repeat:
Get 4.0 mysql binary

$ mysql(4.0) -hmysql_5.1.57_host   -pxxx
ERROR 1043: Bad handshake

Suggested fix:
I briefly checked with debugger and the error was raised here.

sql/sql_connect.cc check_connection(THD *thd)
      Old passwords are zero terminated strings.
    passwd= get_null_terminated_string(&end, &bytes_remaining_in_packet,

  if (passwd == NULL)
    my_error(ER_HANDSHAKE_ERROR, MYF(0), thd->main_security_ctx.host_or_ip);
    return 1;

get_null_terminated_string() returned 0x0, and ER_HANDSHAKE_ERROR was returned.

As far as I checked, MySQL 4.0 client does not send null-terminated password to MySQL. The below was I captured on MySQL server.

        0x0000:  0016 364c a9d1 0024 3817 fc00 0800 4508  ..6L...$8.....E.
        0x0010:  004a bfd3 4000 3e06 5cde 0a09 09eb 0a11  .J..@.>.\.......
        0x0020:  01f0 d357 0cea 800d 1a4a ccac d2a0 8018  ...W.....J......
        0x0030:  05b4 6be7 0000 0101 080a a3c2 a588 2f24  ..k.........../$
        0x0040:  9864 1200 0001 8524 0000 0072 6f6f 7400  .d.....$...root.
        0x0050:  5b5f 434b 5654 4a4e                      [_CKVTJN

It's not ended with 0x0.

char *get_null_terminated_string(char **buffer,
                                 size_t *max_bytes_available,
                                 size_t *string_length)
  char *str= (char *)memchr(*buffer, '\0', *max_bytes_available);

  if (str == NULL)
    return NULL;


*string_length was 8, but 0x0 was not between (*buffer)[0] and (*buffer)[7]. So NULL was returned.
[2 Jun 2011 12:01] MySQL Verification Team
Duplicate of: http://bugs.mysql.com/bug.php?id=61222.