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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>6.40. pam_wheel - only permit root access to members of group wheel</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"><link rel="home" href="Linux-PAM_SAG.html" title="The Linux-PAM System Administrators' Guide"><link rel="up" href="sag-module-reference.html" title="Chapter 6. A reference guide for available modules"><link rel="prev" href="sag-pam_warn.html" title="6.39. pam_warn - logs all PAM items"><link rel="next" href="sag-pam_xauth.html" title="6.41. pam_xauth - forward xauth keys between users"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">6.40. pam_wheel - only permit root access to members of group wheel</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="sag-pam_warn.html">Prev</a> </td><th width="60%" align="center">Chapter 6. A reference guide for available modules</th><td width="20%" align="right"> <a accesskey="n" href="sag-pam_xauth.html">Next</a></td></tr></table><hr></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="sag-pam_wheel"></a>6.40. pam_wheel - only permit root access to members of group wheel</h2></div></div></div><div class="cmdsynopsis"><p><code class="command">pam_wheel.so</code> [ debug ] [ deny ] [ group=<em class="replaceable"><code>name</code></em> ] [ root_only ] [ trust ] [ use_uid ]</p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="sag-pam_wheel-description"></a>6.40.1. DESCRIPTION</h3></div></div></div><p> The pam_wheel PAM module is used to enforce the so-called <span class="emphasis"><em>wheel</em></span> group. By default it permits access to the target user if the applicant user is a member of the <span class="emphasis"><em>wheel</em></span> group. If no group with this name exist, the module is using the group with the group-ID <span class="emphasis"><em>0</em></span>. </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="sag-pam_wheel-options"></a>6.40.2. OPTIONS</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term"> <code class="option">debug</code> </span></dt><dd><p> Print debug information. </p></dd><dt><span class="term"> <code class="option">deny</code> </span></dt><dd><p> 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 <code class="option">group</code> option), deny access. Conversely, if the user is not in the group, return PAM_IGNORE (unless <code class="option">trust</code> was also specified, in which case we return PAM_SUCCESS). </p></dd><dt><span class="term"> <code class="option">group=<em class="replaceable"><code>name</code></em></code> </span></dt><dd><p> Instead of checking the wheel or GID 0 groups, use the <code class="option"><em class="replaceable"><code>name</code></em></code> group to perform the authentication. </p></dd><dt><span class="term"> <code class="option">root_only</code> </span></dt><dd><p> The check for wheel membership is done only when the target user UID is 0. </p></dd><dt><span class="term"> <code class="option">trust</code> </span></dt><dd><p> 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). </p></dd><dt><span class="term"> <code class="option">use_uid</code> </span></dt><dd><p> The check for wheel membership will be done against the current uid instead of the original one (useful when jumping with su from one account to another for example). </p></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="sag-pam_wheel-types"></a>6.40.3. MODULE TYPES PROVIDED</h3></div></div></div><p> The <span class="emphasis"><em>auth</em></span> and <span class="emphasis"><em>account</em></span> module types are provided. </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="sag-pam_wheel-return_values"></a>6.40.4. RETURN VALUES</h3></div></div></div><div class="variablelist"><dl class="variablelist"><dt><span class="term">PAM_AUTH_ERR</span></dt><dd><p> Authentication failure. </p></dd><dt><span class="term">PAM_BUF_ERR</span></dt><dd><p> Memory buffer error. </p></dd><dt><span class="term">PAM_IGNORE</span></dt><dd><p> The return value should be ignored by PAM dispatch. </p></dd><dt><span class="term">PAM_PERM_DENY</span></dt><dd><p> Permission denied. </p></dd><dt><span class="term">PAM_SERVICE_ERR</span></dt><dd><p> Cannot determine the user name. </p></dd><dt><span class="term">PAM_SUCCESS</span></dt><dd><p> Success. </p></dd><dt><span class="term">PAM_USER_UNKNOWN</span></dt><dd><p> User not known. </p></dd></dl></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="sag-pam_wheel-examples"></a>6.40.5. EXAMPLES</h3></div></div></div><p> The root account gains access by default (rootok), only wheel members can become root (wheel) but Unix authenticate non-root applicants. </p><pre class="programlisting"> su auth sufficient pam_rootok.so su auth required pam_wheel.so su auth required pam_unix.so </pre><p> </p></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="sag-pam_wheel-author"></a>6.40.6. AUTHOR</h3></div></div></div><p> pam_wheel was written by Cristian Gafton <gafton@redhat.com>. </p></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sag-pam_warn.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sag-module-reference.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sag-pam_xauth.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">6.39. pam_warn - logs all PAM items </td><td width="20%" align="center"><a accesskey="h" href="Linux-PAM_SAG.html">Home</a></td><td width="40%" align="right" valign="top"> 6.41. pam_xauth - forward xauth keys between users</td></tr></table></div></body></html>