Re: Passwords on Linux systems(for all flavors)
From: Dwayne Ghant (dghant_at_temple.edu)
Date: Mon, 11 Jul 2005 06:07:40 -0700 To: Glynn Clements <firstname.lastname@example.org>
What about unicode charectors in passwords.
Glynn Clements wrote:
>>I would like to know the place where I can find the linux password
>>constraints for the various linux flavors. What I mean is the details
>>like number of key spaces or the key length, the types of charactors
>>that can be used, the restrictions and the number of times the
>>password can be tried if not infinite, etc. I am in need of these
>>details very urgently, so please do help me on this topic.
>On any system which uses PAM (which is almost every modern Linux
>system), most of these are configuration options, controlled through
>the files in /etc/pam.d and /etc/security.
>For the underlying libc crypt() function, assuming MD5 passwords, the
>password can be any NUL-terminated string. There is no minimum or
>maximum length, nor any restriction on which characters (bytes) the
>password can contain.
>However, if a password contains any control characters or non-ASCII
>(8-bit) characters, there may be problems entering it in certain
>contexts. Also, individual programs may read the password into a
>fixed-size buffer, which will impose an upper limit on the length of a
-- Dwayne A. Ghant Application Developer Temple University 215.204.5555 email@example.com