DOKK / manpages / debian 12 / libpam-modules / pam_timestamp.8.en
PAM_TIMESTAMP(8) Linux-PAM Manual PAM_TIMESTAMP(8)

pam_timestamp - Authenticate using cached successful authentication attempts

pam_timestamp.so [timestampdir=directory] [timestamp_timeout=number] [verbose] [debug]

In a nutshell, pam_timestamp caches successful authentication attempts, and allows you to use a recent successful attempt as the basis for authentication. This is similar mechanism which is used in sudo.

When an application opens a session using pam_timestamp, a timestamp file is created in the timestampdir directory for the user. When an application attempts to authenticate the user, a pam_timestamp will treat a sufficiently recent timestamp file as grounds for succeeding.

The default encryption hash is taken from the HMAC_CRYPTO_ALGO variable from /etc/login.defs.

timestampdir=directory

Specify an alternate directory where pam_timestamp creates timestamp files.

timestamp_timeout=number

How long should pam_timestamp treat timestamp as valid after their last modification date (in seconds). Default is 300 seconds.

verbose

Attempt to inform the user when access is granted.

debug

Turns on debugging messages sent to syslog(3).

The auth and session module types are provided.

PAM_AUTH_ERR

The module was not able to retrieve the user name or no valid timestamp file was found.

PAM_SUCCESS

Everything was successful.

PAM_SESSION_ERR

Timestamp file could not be created or updated.

Users can get confused when they are not always asked for passwords when running a given program. Some users reflexively begin typing information before noticing that it is not being asked for.

auth sufficient pam_timestamp.so verbose
auth required   pam_unix.so
session required pam_unix.so
session optional pam_timestamp.so

/var/run/pam_timestamp/...

timestamp files and directories

pam_timestamp_check(8), pam.conf(5), pam.d(5), pam(7)

pam_timestamp was written by Nalin Dahyabhai.

09/03/2021 Linux-PAM Manual