PAM_WHEEL(8)

Linux-PAM Manual

PAM_WHEEL(8)

NAME¶

pam_wheel - Only permit root access to members of group wheel

SYNOPSIS¶

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

DESCRIPTION¶

The pam_wheel PAM module is used to enforce the so-called wheel group. By default it permits root access to the system 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).

use_uid

The check will be done against the real uid of the calling process, instead of trying to obtain the user from the login session associated with the terminal in use.

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>.

04/19/2024