pamfile

Describe the specified Netpbm files

$ pamfile [path/to/file1 path/to/file2 ...]

$ pamfile [[-a|-allimages]] -machine [path/to/file]

$ pamfile [[-cou|-count]] [path/to/file]

pamfile [options] [file...]
pamfile [options] service

[-f | --file]=file_name
    Specifies the PAM configuration file to parse. When this option is used, pamfile reads from the specified file path.

[-s | --service]=service_name
    Specifies the PAM service to display. When this option is used, pamfile will look for a configuration file named service_name within the /etc/pam.d/ directory.

[-v | --verbose]
    Enables verbose output, providing more detailed information during parsing and display, which can be helpful for debugging.

[-q | --quiet]
    Suppresses normal output, showing only error messages. This can be useful for scripting or when checking only for parsing errors.

[-h | --help]
    Displays a help message with usage instructions for the pamfile command and then exits.

[-V | --version]
    Displays the version information of the pamfile utility and then exits.

pamfile is a utility designed to parse and display the contents of a PAM (Pluggable Authentication Modules) configuration file in a human-readable format. Its primary purpose is to help administrators and developers debug or understand how PAM modules are configured for various services. It takes a PAM configuration file (typically located in /etc/pam.d/ or /etc/pam.conf) as input and outputs a structured representation of the rules defined within it.

This output often includes details like the module type (e.g., auth, account, password, session), control flag (e.g., required, requisite, sufficient, optional), module path, and any arguments passed to the module. By pretty-printing the configuration, pamfile makes it easier to spot syntax errors, verify module loading order, and ensure that authentication policies are correctly applied. It's an invaluable tool for maintaining the security and integrity of a Linux system's authentication subsystem.

It's important to note that pamfile is a read-only utility; it does not modify any PAM configuration files. Its purpose is purely for inspection and debugging. While it parses the syntax, it does not perform semantic validation of the PAM modules or their arguments (e.g., it won't check if a module path exists or if specific arguments are valid for a particular module).

pamfile is often used to inspect a specific service's PAM configuration, such as sudo or sshd, by running pamfile -s sudo or pamfile -s sshd. Alternatively, an administrator might directly analyze a configuration file like /etc/pam.d/common-auth using pamfile -f /etc/pam.d/common-auth for a deeper understanding of its rules.

The output of pamfile typically lists each rule line by line, providing a clear, structured format. For each rule, it shows the module type (auth, account, password, session), the control flag (required, requisite, sufficient, optional), the module path (the library file), and any arguments passed to the module. This detailed breakdown is designed for easy readability and debugging of PAM policies.

pamfile is an integral part of the Linux-PAM (Pluggable Authentication Modules for Linux) project. Linux-PAM was developed to provide a flexible and robust authentication framework, inspired by the original PAM framework from Sun Microsystems. As PAM configurations grew in complexity, pamfile emerged as a crucial utility to aid system administrators and developers in understanding and debugging these critical authentication setups. Its development has mirrored the evolution and widespread adoption of the PAM standard across various Linux distributions, emphasizing ease of configuration inspection.

pam(8), pam.conf(5), pam.d(5), login(1), sshd(8), sudo(8)