NAME

pam_wheel - Only permit root access to members of group wheel

SYNOPSIS

pam_wheel.so [debug] [deny] [group=name] [root_only] [trust]

DESCRIPTION

The pam_wheel PAM module is used to enforce the so-called wheel group. By default it permits access to the target user if the applicant user is a member of the wheel group. If no group with this name exist, the module is using the group with the group-ID 0.

OPTIONS

debug

Print debug information.

deny

Reverse the sense of the auth operation: if the user is trying to get UID 0 access and is a member of the wheel group (or the group of the group option), deny access. Conversely, if the user is not in the group, return PAM_IGNORE (unless trust was also specified, in which case we return PAM_SUCCESS).

group=name

Instead of checking the wheel or GID 0 groups, use the name group to perform the authentication.

root_only

The check for wheel membership is done only when the target user UID is 0.

trust

The pam_wheel module will return PAM_SUCCESS instead of PAM_IGNORE if the user is a member of the wheel group (thus with a little play stacking the modules the wheel members may be able to su to root without being prompted for a passwd).

MODULE TYPES PROVIDED

The auth and account module types are provided.

RETURN VALUES

PAM_AUTH_ERR

Authentication failure.

PAM_BUF_ERR

Memory buffer error.

PAM_IGNORE

The return value should be ignored by PAM dispatch.

PAM_PERM_DENY

Permission denied.

PAM_SERVICE_ERR

Cannot determine the user name.

PAM_SUCCESS

Success.

PAM_USER_UNKNOWN

User not known.

EXAMPLES

The root account gains access by default (rootok), only wheel members can become root (wheel) but Unix authenticate non-root applicants.

su      auth     sufficient     pam_rootok.so
su      auth     required       pam_wheel.so
su      auth     required       pam_unix.so

AUTHOR

pam_wheel was written by Cristian Gafton <gafton@redhat.com>.

06/08/2020

Linux-PAM Manual