6.37. pam_wheel - only permit root access to members of group wheel
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## 6.37. pam_wheel - only permit root access to members of group wheel

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

### 6.37.1. 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.

### 6.37.2. 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.

### 6.37.3. MODULE TYPES PROVIDED

The auth and account module types are provided.

### 6.37.4. 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.

### 6.37.5. 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

### 6.37.6. AUTHOR

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

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