'\" t
.\"     Title: suauth
.\"    Author: Marek Michałkiewicz
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 04/01/2024
.\"    Manual: File Formats and Configuration Files
.\"    Source: shadow-utils 4.15.1
.\"  Language: English
.\"
.TH "SUAUTH" "5" "04/01/2024" "shadow\-utils 4\&.15\&.1" "File Formats and Configuration"
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.SH "NAME"
suauth \- detailed su control file
.SH "SYNOPSIS"
.HP \w'\fB/etc/suauth\fR\ 'u
\fB/etc/suauth\fR
.SH "DESCRIPTION"
.PP
The file
/etc/suauth
is referenced whenever the su command is called\&. It can change the behaviour of the su command, based upon:
.sp
.if n \{\
.RS 4
.\}
.nf
      1) the user su is targeting
    
.fi
.if n \{\
.RE
.\}
.PP
2) the user executing the su command (or any groups he might be a member of)
.PP
The file is formatted like this, with lines starting with a # being treated as comment lines and ignored;
.sp
.if n \{\
.RS 4
.\}
.nf
      to\-id:from\-id:ACTION
    
.fi
.if n \{\
.RE
.\}
.PP
Where to\-id is either the word
\fIALL\fR, a list of usernames delimited by "," or the words
\fIALL EXCEPT\fR
followed by a list of usernames delimited by ","\&.
.PP
from\-id is formatted the same as to\-id except the extra word
\fIGROUP\fR
is recognized\&.
\fIALL EXCEPT GROUP\fR
is perfectly valid too\&. Following
\fIGROUP\fR
appears one or more group names, delimited by ","\&. It is not sufficient to have primary group id of the relevant group, an entry in
\fB/etc/group\fR(5)
is necessary\&.
.PP
Action can be one only of the following currently supported options\&.
.PP
\fIDENY\fR
.RS 4
The attempt to su is stopped before a password is even asked for\&.
.RE
.PP
\fINOPASS\fR
.RS 4
The attempt to su is automatically successful; no password is asked for\&.
.RE
.PP
\fIOWNPASS\fR
.RS 4
For the su command to be successful, the user must enter his or her own password\&. They are told this\&.
.RE
.PP
Note there are three separate fields delimited by a colon\&. No whitespace must surround this colon\&. Also note that the file is examined sequentially line by line, and the first applicable rule is used without examining the file further\&. This makes it possible for a system administrator to exercise as fine control as he or she wishes\&.
.SH "EXAMPLE"
.sp
.if n \{\
.RS 4
.\}
.nf
      # sample /etc/suauth file
      #
      # A couple of privileged usernames may
      # su to root with their own password\&.
      #
      root:chris,birddog:OWNPASS
      #
      # Anyone else may not su to root unless in
      # group wheel\&. This is how BSD does things\&.
      #
      root:ALL EXCEPT GROUP wheel:DENY
      #
      # Perhaps terry and birddog are accounts
      # owned by the same person\&.
      # Access can be arranged between them
      # with no password\&.
      #
      terry:birddog:NOPASS
      birddog:terry:NOPASS
      #
    
.fi
.if n \{\
.RE
.\}
.SH "FILES"
.PP
/etc/suauth
.RS 4
.RE
.SH "BUGS"
.PP
There could be plenty lurking\&. The file parser is particularly unforgiving about syntax errors, expecting no spurious whitespace (apart from beginning and end of lines), and a specific token delimiting different things\&.
.SH "DIAGNOSTICS"
.PP
An error parsing the file is reported using
\fBsyslogd\fR(8)
as level ERR on facility AUTH\&.
.SH "SEE ALSO"
.PP
\fBsu\fR(1)\&.