1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2 3<html> 4 <head> 5 <meta name="generator" content="HTML Tidy, see www.w3.org"> 6 <title>User Identification</title> 7 <meta name="GENERATOR" content= 8 "Modular DocBook HTML Stylesheet Version 1.7"> 9 <link rel="HOME" title=" LPRng Reference Manual" href= 10 "index.htm"> 11 <link rel="UP" title= 12 "LPRng Clients - lpr, lprm, lpq, lpc, lpstat " href= 13 "lprngclients.htm"> 14 <link rel="PREVIOUS" title="Force Connection to Localhost " 15 href="forcelocalhost.htm"> 16 <link rel="NEXT" title="lpr - Job Spooler Program" href= 17 "lpr.htm"> 18 </head> 19 20 <body class="SECT1" bgcolor="#FFFFFF" text="#000000" link= 21 "#0000FF" vlink="#840084" alink="#0000FF"> 22 <div class="NAVHEADER"> 23 <table summary="Header navigation table" width="100%" border= 24 "0" cellpadding="0" cellspacing="0"> 25 <tr> 26 <th colspan="3" align="center">LPRng Reference Manual: 5 27 Sep 2003 (For LPRng-3.8.22)</th> 28 </tr> 29 30 <tr> 31 <td width="10%" align="left" valign="bottom"><a href= 32 "forcelocalhost.htm" accesskey="P">Prev</a></td> 33 34 <td width="80%" align="center" valign="bottom">Chapter 5. 35 <b class="APPLICATION">LPRng</b> Clients - lpr, lprm, 36 lpq, lpc, lpstat</td> 37 38 <td width="10%" align="right" valign="bottom"><a href= 39 "lpr.htm" accesskey="N">Next</a></td> 40 </tr> 41 </table> 42 <hr align="LEFT" width="100%"> 43 </div> 44 45 <div class="SECT1"> 46 <h1 class="SECT1"><a name="ALLOWUSERSETTING">5.9. User 47 Identification</a></h1> 48 49 <p>Options used:</p> 50 51 <ul> 52 <li> 53 <p><var class="LITERAL">allow_user_setting=</var><span 54 class="emphasis"><i class="EMPHASIS">privileged 55 users</i></span></p> 56 </li> 57 </ul> 58 <br> 59 <br> 60 61 <p>When an client program sends a command to the <b class= 62 "APPLICATION">lpd</b> server it may need to provide the name 63 of the user who is originating the request for service. This 64 name is obtained by looking up the UID of the user running 65 the client in the appropriate user information database; if 66 the information is not found the UID is used instead. Also, 67 the client machine hostname may also be needed. This is 68 usually determined by using a DNS lookup and trying to 69 determine if there is a canonical or Fully Qualified Domain 70 Name for the host and using this.</p> 71 72 <p>The <tt class="COMMAND">lpr -U name@host</tt> (and for <b 73 class="APPLICATION">lpq</b>, <b class="APPLICATION">lprm</b>, 74 and <b class="APPLICATION">lpc</b>) option allows privileged 75 users to cause the client software to use the <var class= 76 "LITERAL">name</var> value as the originator and <var class= 77 "LITERAL">host</var> as the machine name. This allows 78 privileged users to <span class="emphasis"><i class= 79 "EMPHASIS">impersonate</i></span> other users. This is most 80 useful for programs such as Samba and PCNFS, which need to 81 act as proxies for users.</p> 82 83 <p>By default, ROOT (UID 0) is the only user that can 84 masquerade as another user. The <var class= 85 "LITERAL">allow_user_setting=name,name...</var> configuration 86 option can be used to specify a list of names or UIDs that 87 can also perform masquerading. For example, if the Samba 88 server was running as user <var class="LITERAL">samba</var>, 89 then <var class="LITERAL">allow_user_setting=samba</var> 90 would allow it to specify the name of print job originator as 91 a remote user, and the remote user would not need a login 92 account on the system.</p> 93 </div> 94 95 <div class="NAVFOOTER"> 96 <hr align="LEFT" width="100%"> 97 98 <table summary="Footer navigation table" width="100%" border= 99 "0" cellpadding="0" cellspacing="0"> 100 <tr> 101 <td width="33%" align="left" valign="top"><a href= 102 "forcelocalhost.htm" accesskey="P">Prev</a></td> 103 104 <td width="34%" align="center" valign="top"><a href= 105 "index.htm" accesskey="H">Home</a></td> 106 107 <td width="33%" align="right" valign="top"><a href= 108 "lpr.htm" accesskey="N">Next</a></td> 109 </tr> 110 111 <tr> 112 <td width="33%" align="left" valign="top">Force 113 Connection to Localhost</td> 114 115 <td width="34%" align="center" valign="top"><a href= 116 "lprngclients.htm" accesskey="U">Up</a></td> 117 118 <td width="33%" align="right" valign="top"><b class= 119 "APPLICATION">lpr</b> - Job Spooler Program</td> 120 </tr> 121 </table> 122 </div> 123 </body> 124</html> 125 126