Description: Fix for bug CVE-2012-5611 (bug 67685) is 
incomplete. The ACL_KEY_LENGTH-sized buffers in acl_get() and 
check_grant_db() can be overflown by up to two bytes. That's 
probably not enough to do anything more serious than crashing 
mysqld.
Analysis: In acl_get() when "copy_length" is calculated it 
just adding the variable lengths. But when we are using them 
with strmov() we are adding +1 to each. This will lead to a 
three byte buffer overflow (i.e two +1's at strmov() and one 
byte for the null added by strmov() function). Similarly it 
happens for check_grant_db() function as well.
Fix: We need to add "+2" to "copy_length" in acl_get() 
and "+1" to "copy_length" in check_grant_db().