revno: 3690.1.180
committer: gopal.shankar@oracle.com
branch nick: mysql-flushpriv2
timestamp: Thu 2012-03-29 00:20:54 +0530
message:
  Bug#12766319 - 61865: RENAME USER DOES NOT WORK CORRECTLY -
                        REQUIRES FLUSH PRIVILEGES

  PROBLEM:
    RENAME USER does not work as expected when from_user contains just
  IP and to_user contains IP/MASK. Attempt to connect to MySQL using
  renamed user fails. Attempts to connect succeed only after command
  FLUSH PRIVILEGES.

  ANALYSIS:
    MySQL maintains access control list for users in global DYNAMIC ARRAY
  'acl_users'. This list is updated by acl_reload(), which loads 'acl_users'
  from mysql.user table.

    For faster search we maintain HASH acl_check_hosts, which contains
  user details with hostnames without any wild cards. All the users whose
  host name contains wild cards are stored in DYNAMIC_ARRAY acl_wild_hosts.

    ADD/DROP/RENAME user basically updates 'acl_users' along with mysql.user.
  At the end of these operations init_check_hosts() is called to update
  acl_check_hosts and  acl_wild_cards based on 'acl_users'.

  Bug#12766319 - 61865: RENAME USER DOES NOT WORK CORRECTLY -
                        REQUIRES FLUSH PRIVILEGES

  PROBLEM:
    RENAME USER does not work as expected when from_user contains just
  IP and to_user contains IP/MASK. Attempt to connect to MySQL using
  renamed user fails. Attempts to connect succeed only after command
  FLUSH PRIVILEGES.

  ANALYSIS:
    MySQL maintains access control list for users in global DYNAMIC ARRAY
  'acl_users'. This list is updated by acl_reload(), which loads 'acl_users'
  from mysql.user table.

    For faster search we maintain HASH acl_check_hosts, which contains
  user details with hostnames without any wild cards. All the users whose
  host name contains wild cards are stored in DYNAMIC_ARRAY acl_wild_hosts.

    ADD/DROP/RENAME user basically updates 'acl_users' along with mysql.user.
  At the end of these operations init_check_hosts() is called to update
  acl_check_hosts and  acl_wild_cards based on 'acl_users'.

    During RENAME, when it updates 'acl_users' in handle_grant_struct(),
  hostname is copied into 'acl_users' list updating only ACL_USER->hostname
  but it does not update ACL_USER->host->ip, ACL_USER->host->ip_mask. This
  is route cause for this bug.

    FLUSH PRIVILEGES command invokes acl_reload(). This function updates all
  members of ACL_USER->host (including ip and ip_mask). Hence attempts to connect
  to MySQL succeeds there after.

  FIX:
    Make changes to handle_grant_struct() to properly update ACL_USER->host->ip,
  ACL_USER->host->ip_mask. This is done using existing update_hostname().

  Note:
    In addition to the fix described above, the code related to acl_host_and_ip is
  modified. The new code helps avoid doing similar mistakes, of updating
  hostname, without updating ip_mask. These changes also improves the related code.