MERGED PROJECT!!! I WILL UPDATE THIS README IN THE NEXT DAYS!!! THE FOLLOWING DOCUMENTATION WILL NOT WORK ACTUALLY!

chkusr

chkusr is a set of programs to verify information about a user on UNIX based systems.

• The idea
  • Requirements
  • Building chkusr
  • Installation
  • Uninstall
• chkgrp
• chkpwd
  • Usage
    • Return codes
    • Examples
      • Interactive mode asking for a username and a password
      • Interactive mode only asking for a password
      • None interactive mode with username and password provided as arguments to chkpwd
      • Request the result from the above commands
  • Custom build
• Links
• License

The idea

I needed some programs to verify some information about users and groups on a Linux/UNIX system just returning 0 on success and 1 on error.

Currently chkpwd is only tested on Linux, but it should work on a AIX, DragonFly BSD, FreeBSD, HP-UX, Linux, macOS, NetBSD and Solaris operating system too.

Requirements

You need the PAM development package installed. On Alpine it is named linux-pam-dev, on Debian based systems it is libpam0g-dev.

Building chkusr

git clone https://git.xw3.org/hanez/chkusr.git
cd chkusr
make

Installation

WARNING: Install this software with care. chkpwd could easily be used for bruteforcing passwords from local users!

sudo make install

chkusr programs are installed to /usr/bin/.

chkpwd.h is installed to /usr/include/ for use in other applications.

Uninstall

sudo make uninstall

chkgrp

chkgrp is a program to verify if a user is a member of a group.

More information will follow... Actually there are multiple programs with some different behavior. I will write more about this, but for now I will not.

chkpwd

chkpwd is a program that checks the validity of a users password on a UNIX/PAM-based system.

The code only supports verifying passwords for user id 1000 by default. Look at the file chkpwd.h for some compile time options!

Usage

chkpwd -h
Usage: chkpwd [-u <username>] [-p <password>] [-v] [-V] [-h]

Options:
  -u <username>  Set username.
  -p <password>  Set password.
  -v             Enable verbose mode.
  -V             Print program version.
  -h             Show this help.

You can also use chkpwd even without installing by just running the following command:

./chkpwd

Return codes

chk returns 0 on success, 1 otherwise.

Examples

Interactive mode asking for a username and a password

chkpwd

Interactive mode only asking for a password

chkpwd -u hanez

None interactive mode with username and password provided as arguments to chkpwd

chkpwd -u hanez -p password

Request the result from the above commands

echo $?

Custom build

Set MAX_UID and MIN_UID at compile time:

gcc -Wall -DMAX_UID=1000 -DMIN_UID=1000 -o chkpwd chkpwd.c -lpam -lpam_misc

Links

• https://git.xw3.org/hanez/chkusr
• https://github.com/shadow-maint/shadow
• https://github.com/linux-pam/linux-pam
• https://www.man7.org/linux/man-pages/man8/unix_chkpwd.8.html
• https://cr.yp.to/checkpwd.html
• https://pamtester.sourceforge.net/
• https://github.com/AlexanderZhirov/chkpass
• https://github.com/ViKingIX/pam_test
• https://github.com/Dareka826/chk_pw

License

chkusr is licensed under the Apache License, Version 2.0.

See LICENSE for details.