136 lines
4.3 KiB
Groff
136 lines
4.3 KiB
Groff
.\" $NetBSD: setuid.2,v 1.6 1999/03/22 19:45:09 garbled Exp $
|
|
.\"
|
|
.\" Copyright (c) 1983, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)setuid.2 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.Dd June 4, 1993
|
|
.Dt SETUID 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm setuid ,
|
|
.Nm seteuid ,
|
|
.Nm setgid ,
|
|
.Nm setegid
|
|
.Nd set user and group ID
|
|
.Sh SYNOPSIS
|
|
.Fd #include <sys/types.h>
|
|
.Fd #include <unistd.h>
|
|
.Ft int
|
|
.Fn setuid "uid_t uid"
|
|
.Ft int
|
|
.Fn seteuid "uid_t euid"
|
|
.Ft int
|
|
.Fn setgid "gid_t gid"
|
|
.Ft int
|
|
.Fn setegid "gid_t egid"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn setuid
|
|
function
|
|
sets the real and effective
|
|
user IDs and the saved set-user-ID of the current process
|
|
to the specified value.
|
|
The
|
|
.Fn setuid
|
|
function is permitted if the specified ID is equal to the real user ID
|
|
of the process, or if the effective user ID is that of the super user.
|
|
.Pp
|
|
The
|
|
.Fn setgid
|
|
function
|
|
sets the real and effective
|
|
group IDs and the saved set-group-ID of the current process
|
|
to the specified value.
|
|
The
|
|
.Fn setgid
|
|
function is permitted if the specified ID is equal to the real group ID
|
|
of the process, or if the effective user ID is that of the super user.
|
|
.Pp
|
|
The
|
|
.Fn seteuid
|
|
function
|
|
.Pq Fn setegid
|
|
sets the effective user ID (group ID) of the
|
|
current process.
|
|
The effective user ID may be set to the value
|
|
of the real user ID or the saved set-user-ID (see
|
|
.Xr intro 2
|
|
and
|
|
.Xr execve 2 ) ;
|
|
in this way, the effective user ID of a set-user-ID executable
|
|
may be toggled by switching to the real user ID, then re-enabled
|
|
by reverting to the set-user-ID value.
|
|
Similarly, the effective group ID may be set to the value
|
|
of the real group ID or the saved set-user-ID.
|
|
.Pp
|
|
.Sh RETURN VALUES
|
|
Upon success, these functions return 0;
|
|
otherwise \-1 is returned.
|
|
.Pp
|
|
If the user is not the super user, or the uid
|
|
specified is not the real, effective ID, or saved ID,
|
|
these functions return \-1.
|
|
.Sh SEE ALSO
|
|
.Xr getuid 2 ,
|
|
.Xr getgid 2
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn setuid
|
|
and
|
|
.Fn setgid
|
|
functions are compliant with the
|
|
.St -p1003.1-90
|
|
specification with
|
|
.Li _POSIX_SAVED_IDS
|
|
not defined.
|
|
We do not implement the
|
|
.Li _POSIX_SAVED_IDS
|
|
option as specified in the standard
|
|
because this would make it impossible for a set-user-ID executable owned
|
|
by a user other than the super-user to permanently revoke its privileges.
|
|
.Pp
|
|
The
|
|
.Fn seteuid
|
|
and
|
|
.Fn setegid
|
|
functions are extensions based on the
|
|
.Tn POSIX
|
|
concept of
|
|
.Li _POSIX_SAVED_IDS ,
|
|
and have been proposed for a future revision of the standard.
|
|
They provide the same feature of toggling effective IDs as
|
|
.Li _POSIX_SAVED_IDS ,
|
|
but do so independent of the current effective
|
|
ID, rather than requiring the super-user to permanently revoke its
|
|
privileges.
|