enforce maxlength in usernames

[walter harms]

Am 28.07.2011 07:33, schrieb Lauri Kasanen:
>> Hi,
>> Could  this be more acceptable. Could be improved by removing
>> the double strlen also the error message could be better.
>> Just to see if I overlooked something obvious.
>>
>> Ciao,
>> Tito
>>
>> void FAST_FUNC die_if_bad_username(const char *name)
>> {
>> 	/* Enforce length limits on usernames. 
>> 	 * LOGIN_NAME_MAX: Maximum length of a login name,
>> 	 * including the terminating null byte.
>> 	 * Must not be less than _POSIX_LOGIN_NAME_MAX (9).
>> 	 */
>> 	if (!name 
>> 	 || strlen(name) + 1 > sysconf(_SC_LOGIN_NAME_MAX)
>> 	 || strlen(name) + 1 < _POSIX_LOGIN_NAME_MAX
> 
> That is no minimum, it's a minimum of the maximum. Consider names like
> "root", "lp".
> 
> - Lauri
> 

Hi all,
there is an RFC describing what a "Username" may look like, implementing it
is clearly overheat here. More interessting is RFC5321. http://tools.ietf.org/html/rfc5321#section-4.5.3.1
It recommends a maximum up to 64 "octets" (aka bytes).
I guess it would simplify life if we drop the IF THEN ELSE stuff and use 64 byte as limit.

re,
 wh