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
• 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).
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 <kukuk@thkukuk.de>.
Linux-PAM 06/29/2025 PAM_UMASK(8)
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