Manual: pam_umask

PAM_UMASK(8)					      Linux-PAM Manual						PAM_UMASK(8)

NAME
       pam_umask - PAM module to set the file mode creation mask

SYNOPSIS

       pam_umask.so [debug] [silent] [usergroups] [nousergroups] [umask=mask]

DESCRIPTION
       pam_umask is a PAM module to set the file mode creation mask of the current environment. The umask affects the
       default permissions assigned to newly created files.

       The PAM module tries to get the umask value from the following places in the following order:

       •   umask= entry in the user's GECOS field (see below for details)

       •   umask= argument

       •   UMASK entry from /etc/login.defs (influenced by USERGROUPS_ENAB in /etc/login.defs)

       •   UMASK= entry from /etc/default/login

       The GECOS field is split on comma ',' characters. Entries must be set in its 'other' (sub-)field (the 5th field
       within the GECOS field), which could be done, for example, using chfn --other. In addition to the umask= entry, the
       module also recognizes the pri= entry, which sets the nice priority value for the session, and the ulimit= entry,
       which sets the maximum size of files the processes in the session can create.

OPTIONS
       debug
	   Print debug information.

       silent
	   Don't print informative messages.

       usergroups
	   If the user is not root and the username is the same as primary group name, the umask group bits are set to be
	   the same as owner bits (examples: 022 -> 002, 077 -> 007). Note that using this option explicitly is discouraged.
	   pam_umask enables this functionality by default if /etc/login.defs enables USERGROUPS_ENAB, and the umask is not
	   set explicitly in other places than /etc/login.defs (this is compatible with login's behaviour without PAM).

       nousergroups
	   This is the direct opposite of the usergroups option described above, which can be useful in case pam_umask has
	   been compiled with usergroups enabled by default and you want to disable it at runtime.

       umask=mask
	   Sets the calling process's file mode creation mask (umask) to mask & 0777. The value is interpreted as Octal.

MODULE TYPES PROVIDED
       Only the session type is provided.

RETURN VALUES
       PAM_SUCCESS
	   The new umask was set successfully.

       PAM_BUF_ERR
	   Memory buffer error.

       PAM_CONV_ERR
	   The conversation method supplied by the application failed to obtain the username.

       PAM_INCOMPLETE
	   The conversation method supplied by the application returned PAM_CONV_AGAIN.

       PAM_SERVICE_ERR
	   No username was given.

       PAM_USER_UNKNOWN
	   User not known.

EXAMPLES
       Add the following line to /etc/pam.d/login to set the user specific umask at login:

		   session optional pam_umask.so umask=0022

SEE ALSO
       pam.conf(5), pam.d(5), pam(7)

AUTHOR
       pam_umask was written by Thorsten Kukuk .

Linux-PAM						 07/16/2026						PAM_UMASK(8)