https://github.com/hanez/chkpwd
chkpwd is a program that checks the validity of a users password on a UNIX / PAM-based system. (mirror from: https://git.xw3.org/hanez/chkpwd)
https://github.com/hanez/chkpwd
authentication cgi checkpassword checkpw chkpwd linux pam passwd password shadow shell unix
Last synced: 8 months ago
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chkpwd is a program that checks the validity of a users password on a UNIX / PAM-based system. (mirror from: https://git.xw3.org/hanez/chkpwd)
- Host: GitHub
- URL: https://github.com/hanez/chkpwd
- Owner: hanez
- License: other
- Created: 2024-08-27T23:19:42.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2025-06-04T17:06:35.000Z (8 months ago)
- Last Synced: 2025-06-04T22:19:46.767Z (8 months ago)
- Topics: authentication, cgi, checkpassword, checkpw, chkpwd, linux, pam, passwd, password, shadow, shell, unix
- Language: C
- Homepage: https://git.xw3.org/hanez/chkpwd
- Size: 38.1 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# chkpwd
chkpwd is a program that checks the validity of a users password on a UNIX/[PAM](https://en.wikipedia.org/wiki/Pluggable_Authentication_Module)-based system.
Currently chkpwd is only tested on Linux, but it should work on a [AIX](https://en.wikipedia.org/wiki/IBM_AIX), [DragonFly BSD](https://www.dragonflybsd.org/), [FreeBSD](https://www.freebsd.org/), [HP-UX](https://en.wikipedia.org/wiki/HP-UX), [Linux](https://kernel.org/), [macOS](https://en.wikipedia.org/wiki/MacOS), [NetBSD](https://netbsd.org/) and [Solaris](https://en.wikipedia.org/wiki/Oracle_Solaris) operating system too.
## The idea
I needed a program to verify passwords of users on Linux/UNIX systems using PAM that just returns 0 on success and 1 on error.
## 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 chkpwd
```
git clone https://git.xw3.org/hanez/chkpwd.git
cd chkpwd
make
```
The code only supports verifying passwords for user id 1000 by default. Look at the file chkpwd.h for some compile time options!
### Custom build example
Set MAX_UID and MIN_UID at compile time:
```
gcc -Wall -DMAX_UID=1000 -DMIN_UID=1000 -o chkpwd chkpwd.c -lpam -lpam_misc
```
## Installation
**WARNING:** Install this software with care. chkpwd could easily be used for bruteforcing passwords from local users!
```
sudo make install
```
chkpwd is installed to /usr/bin/.
chkpwd.h is installed to /usr/include/ for use in other applications.
## Uninstall
```
sudo make uninstall
```
## Usage
```
chkpwd -h
Usage: chkpwd [-u ] [-p ] [-v] [-V] [-h]
Options:
-u Set username.
-p 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
chkpwd 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 $?
```
## License
chkpwd is licensed under the Apache License, Version 2.0.
See LICENSE for details.
## Links
- [https://git.xw3.org/hanez/chkpwd](https://git.xw3.org/hanez/chkpwd)
- [https://www.man7.org/linux/man-pages/man8/unix_chkpwd.8.html](https://www.man7.org/linux/man-pages/man8/unix_chkpwd.8.html)
- [https://cr.yp.to/checkpwd.html](https://cr.yp.to/checkpwd.html)
- [https://pamtester.sourceforge.net/](https://pamtester.sourceforge.net/)
- [https://github.com/AlexanderZhirov/chkpass](https://github.com/AlexanderZhirov/chkpass)
- [https://github.com/ViKingIX/pam_test](https://github.com/ViKingIX/pam_test)
- [https://github.com/Dareka826/chk_pw](https://github.com/Dareka826/chk_pw)