Re: Passwords on Linux systems(for all flavors)

From: Dwayne Ghant (dghant_at_temple.edu)
Date: 07/11/05

  • Next message: Glynn Clements: "Re: Passwords on Linux systems(for all flavors)"
    Date: Mon, 11 Jul 2005 06:07:40 -0700
    To: Glynn Clements <glynn@gclements.plus.com>
    
    

    What about unicode charectors in passwords.
    Glynn Clements wrote:

    >shyaam@gmail.com 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
    >password.
    >
    >
    >

    -- 
    Dwayne A. Ghant
    Application Developer
    Temple University
    215.204.5555
    dghant@temple.edu
     
    

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