---
name: "pam_matrix"
section: "8"
platform: "linux"
package: "pam_wrapper"
version: "1.1.8-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/pam_matrix"
---

# pam\_matrix(8)

A PAM test module to retrieve module-specific PAM items

## NAME

pam\_matrix - A PAM test module to retrieve module-specific PAM items

## SYNOPSIS

pam\_matrix.so \[...\]

## DESCRIPTION

Testing PAM application often requires to set up an authentication backend with as little effort as possible. The **pam\_matrix** module allows one to authenticate against a key-value text file, provided by an option or with an environment variable.

## IMPORTANT

pam\_matrix is a **test tool**. It should be considered completely insecure and never used outside test environments! As you’ll see when reading description of the options and actions, many of them don’t make any sense in the real world and were added just to make tests possible.

## PASSWORD DATABASE

The pam\_matrix module authenticates user against a plain-text CSV file. The format of the file is as follows:

```
username:password:allowed_service
```

Example: User bob allowed to authenticate with the service sshd

```
bob:secret:sshd
```

## OPTIONS

• **passdb=/path/to/file** - the patch to the password database. If the database is not provided with this module option, pam\_matrix.so reads the PAM\_MATRIX\_PASSWD environment variable and tries to load the file from there. If that fails as well, PAM\_AUTHINFO\_UNAVAIL is returned.

• **echo** - if this option is provided, pam\_matrix.so will ask for password using PAM\_PROMPT\_ECHO\_ON, that is, the password will be echoed back to user. This option was added to make it possible to test conversation functions better.

• **verbose** - if this option is provided, pam\_matrix.so will display a PAM\_TEXT\_INFO message when authentication succeeds and a PAM\_ERROR\_MSG when authentication fails. This option was added to make it possible to test conversation functions better.

## MODULE TYPES PROVIDED

All module types (**account**, **auth**, **password** and **session**) are supported.

The **auth** module searches for the user in the passdb file and compares the provided password with the one in the passdb file.

The **password** module is able to update the password in the passdb file.

The **access** module compares the service name the PAM conversation was invoked with the allowed service for the user as set in the passdb file.

The **session** module sets the HOMEDIR PAM environment variable to "/home/%u" where %u stands for the user who opens the session. The variable is unset on session close.

## EXAMPLE

```
auth        required    pam_matrix.so passdb=/tmp/passdb verbose
account     required    pam_matrix.so passdb=/tmp/passdb verbose
password    required    pam_matrix.so passdb=/tmp/passdb verbose
session     required    pam_matrix.so passdb=/tmp/passdb verbose
```