check user password

toredo · 12-08-2009, 01:49 AM

hello,

i search for a way to check a user password. i know the passwords are saved in /etc/shadow, but i can't regenerate and compare them.

i prfer c/c++, but if it much easier i can use perl or shell script to.

please help me.

best regards
toredo

EricTRA · 12-08-2009, 01:57 AM

Hello,

What's the reason why you want to 'check' user passwords? They are personal and private and trying to find out another persons password by means other then asking that user, is considered hacking in my opinion. If you want to control the password strength of a user's password then you'll have to imply the use of it on your system, using for example pam modules like pam_cracklib.

You can read up on it here.

Kind regards,

Eric

neonsignal · 12-08-2009, 02:13 AM

The system is designed so that you do not need to regenerate passwords in order to check them. Instead you use the crypt function to encrypt the password that is input, and compare it against the encrypted value in the /etc/shadow file.

toredo · 12-08-2009, 02:33 AM

Quote:

Originally Posted by EricTRA

Hello,

What's the reason why you want to 'check' user passwords? They are personal and private and trying to find out another persons password by means other then asking that user, is considered hacking in my opinion. If you want to control the password strength of a user's password then you'll have to imply the use of it on your system, using for example pam modules like pam_cracklib.

You can read up on it here.

Kind regards,

Eric

sry, my english is bad, but i wouldn't crack the password. no i would only check a password for a user (is a litle bit like sudo).

@neonsignal
thx, i'll try it. thx

best regards
toredo

mohit_parihar · 12-08-2009, 03:57 AM

hello
right now a i am working on foreground(fg) & background (bg),so kindly provide me source code for fg & bg command.

EricTRA · 12-08-2009, 04:12 AM

Hello,

Both are part of the job control system that comes with the shell (Job Control). If you want the source code then look at a site like http://www.linuxfromscratch.com. They have links to all the packages to build a Linux system from scratch, so also for the shell.

Kind regards,

Eric