checkpw

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

The idea behind:

I needed a program to verify passwords of users on Linux based systems using PAM.

Exactly a program like this... not more!

Installation:

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

git clone https://git.xw3.org/xw3/checkpw.git
cd checkpw
make
sudo make install

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

Manual installation:

Set MAX_UID and MIN_UID in the code or you can compile checkpw without editing the code using the following command and install it manually:

gcc -Wall -DMAX_UID=1000 -DMIN_UID=1000 -o checkpw checkpw.c -lpam -lpam_misc
sudo cp ./checkpw /usr/bin/

Uninstall:

sudo make uninstall

Usage:

checkpw -h
Usage: checkpw [-u <username>] [-p <password>] [-i] [-v] [-h]

Options:
  -u <username>  Specify username.
  -p <password>  Specify password.
  -i             Enable interactive mode to prompt for missing username/password.
  -v             Enable verbose mode.
  -V             Show program version.
  -h             Show this help.

Returns 0 on success, 1 otherwise.

Examples:

Interactive mode:

checkpw -i

Interactive mode only asking for a password:

checkpw -u hanez -i

None interactive mode with username and password provided as arguments to checkpw:

checkpw -u hanez -p password

Request the result from the above commands:

echo $?

Links:

• https://cr.yp.to/checkpwd.html
• https://pamtester.sourceforge.net/