Creating password hash.

knockout_artist · 10-27-2009, 02:12 PM

Hi,

I need to create password hash. Reason I need it so I can use it to create user account with one line "useradd" command.
Some thing like this.

#useradd username -p <hash>

What I have found out is

"makepasswd"
is different as it use to be ??
What I found on the Internet makepasswd seems like it has what I need.

Code:



makepasswd(1)                UNIX Reference Manual               makepasswd(1)

NAME
       makepasswd - generate and/or encrypt passwords

SYNOPSIS
       makepasswd [ --chars N ] [ --clearfrom file ] [ --count N ] [ --crypt |
       --nocrypt | --crypt-md5 ] [ --cryptsalt N ] [ --help ] [ --maxchars N ]
       [ --minchars N ] [ --randomseed N ] [ --rerandom N ] [ --repeatpass N ]
       [ --string string ] [ --verbose | --noverbose ]

DESCRIPTION
       makepasswd generates true random passwords  by  using  the  /dev/random
       feature  of Linux, with the emphasis on security over pronounceability.
       It can also encrypt plaintext passwords given on the command line.

OPTIONS
       --chars N
              Generate passwords with exactly N characters (do  not  use  with
              options --minchars and --maxchars).

       --clearfrom FILE
              Use   password   from  FILE  instead  of  generating  passwords.
              Requires the --crypt or the --crypt-md5 options; may not be used
              with  these  options:  --chars, --maxchars, --minchars, --count,
              --string, --nocrypt.  Trailing newlines are  removed  but  other
              white space is not.

       --count N
              Produce a total of N passwords (the default is one).

       --crypt
              Produce encrypted passwords.

       --crypt-md5
              Produce  encrypted  passwords  using the MD5 digest (hash) algo-
              rithm.


<TRIMMED>

But I was only able to find makepasswd from freashmeat.org. Afetr installing it what I have is

Code:

$ makepasswd --help
Usage: makepasswd [option [value]] ...
	-c, --chars	string of allowed characters (A..Za..z0..9)
	-e, --encrypt	encryption algorithm {none,des,md5,shmd5} (none)
	-l, --length	password length
	-M, --max	password maximum length (8)
	-m, --min	password minimum length (8)
	-n, --number	number of passwords to generate (1)
	-p, --password	password to use
	-s, --salt	salt to use (random)
	-h, --help	display this help screen
	-V, --version	display program version

Its not the same utility.

Any suggestion about,

1-where to find real makepasswd.
2-If not, how do I get password hash exactly the way it looks in "/etc/shadow" file.

Thanks

iambryan · 10-27-2009, 02:27 PM

In RedHat I accomplish the scripting of user passwords in the following way (with an externally generated password as $pass):

pass=1234abcd
echo $pass | sudo passwd --stdin $username > /dev/null

Hope this helps

Bryan

spindler · 11-02-2009, 10:27 PM

I have the same problem. In my case I'm trying to generate password hashes that are suitable for Unix when a user logs into a web portal, but I don't want to create local accounts.

sundialsvcs · 11-02-2009, 11:33 PM

Commands like useradd will generate appropriately hashed password-values where and when they are needed. You don't supply the hashed values yourself.

Hashed passwords are normally calculated using algorithms such as sha1 or (less commonly these days) md5. Functions to produce them are readily available in whatever is your language of choice.

spindler · 11-04-2009, 06:49 AM

useradd doesn't really work as that does local account management. Think a web portal where a user creates an account and as they are granted privileges accounts are created for them on various machines. For security reasons you don't want to keep their password around, instead you want to create the appropriate password hashes that you might need later. Generic MD5 doesn't work b/c the password hash is salted and has some other odd bits done to it. I managed to find a perl module that would generate it for me so I'm good.