6.35. 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.

6.35.2. OPTIONS

  • 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.



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

    • Everything was successful.

    • Timestamp file could not be created or updated.

6.35.5. NOTES

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.

6.35.6. EXAMPLES

auth sufficient pam_timestamp.so verbose
auth required   pam_unix.so

session required pam_unix.so
session optional pam_timestamp.so

6.35.7. FILES

  • /var/run/pam_timestamp/...

    • timestamp files and directories

6.35.8. AUTHOR

pam_timestamp was written by Nalin Dahyabhai.