---
name: "libpam-ssh"
section: "8"
platform: "linux"
package: "libpam-ssh"
version: "1.91.0-9.3+lenny1"
release: "Debian 5.0 (Lenny)"
platforms: ["linux"]
url: "https://new.carta.tech/libpam-ssh"
---

# libpam-ssh(8)

authentication and session management with SSH private keys

## NAME

**pam\_ssh** – authentication and session management with SSH private keys

## SYNOPSIS

\[*service-name*\] *module-type* *control-flag* *pam\_ssh* \[*options*\]

## DESCRIPTION

The SSH authentication service module for PAM, **pam\_ssh** provides functionality for two PAM categories: authentication and session management. In terms of the *module-type* parameter, they are the “auth” and “session” features. It also provides null functions for the remaining categories.

### SSH Authentication Module

The SSH authentication component provides a function to verify the identity of a user (**pam\_sm\_authenticate**()), by prompting the user for a passphrase and verifying that it can decrypt the target user's SSH key using that passphrase.

The following options may be passed to the authentication module:

- **debug**

  [syslog(3)](/syslog/3.md) debugging information at LOG\_DEBUG level.

- **use\_first\_pass**

  If the authentication module is not the first in the stack, and a previous module obtained the user's password, that password is used to authenticate the user. If this fails, the authentication module returns failure without prompting the user for a password. This option has no effect if the authentication module is the first in the stack, or if no previous modules obtained the user's password.

- **try\_first\_pass**

  This option is similar to the **use\_first\_pass** option, except that if the previously obtained password fails, the user is prompted for another password.

- **keyfiles**

  Specify the comma-separated list of files in *$HOME/.ssh* to check for SSH keys. The default is “id\_dsa,id\_rsa,identity”.

### SSH Session Management Module

The SSH session management component provides functions to initiate (**pam\_sm\_open\_session**()) and terminate (**pam\_sm\_close\_session**()) sessions. The **pam\_sm\_open\_session**() function starts an SSH agent, passing it any private keys it decrypted during the authentication phase, and sets the environment variables the agent specifies. The **pam\_sm\_close\_session**() function kills the previously started SSH agent by sending it a SIGTERM.

The following options may be passed to the session management module:

- **debug**

  [syslog(3)](/syslog/3.md) debugging information at LOG\_DEBUG level.

## FILES

- *$HOME/.ssh/identity*

  SSH1/OpenSSH RSA key

- *$HOME/.ssh/id\_dsa*

  OpenSSH DSA key

- *$HOME/.ssh2/id\_rsa\_\**

  SSH2 RSA keys

- *$HOME/.ssh2/id\_dsa\_\**

  SSH2 DSA keys

## SEE ALSO

[ssh-agent(1)](/ssh-agent/1.md), [syslog(3)](/syslog/3.md), [pam.conf(5)](/pam.conf/5.md), [pam(8)](/pam/8.md)

## AUTHORS

Andrew J. Korty ⟨ajk@iu.edu⟩ wrote **pam\_ssh**. Dag-Erling Smorgrav wrote the original OpenPAM support code. Mark R V Murray wrote the original version of this manual page.