166 lines
4.8 KiB
Groff
166 lines
4.8 KiB
Groff
.\" $NetBSD: setuid.2,v 1.3 1995/02/27 12:37:06 cgd Exp $
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.\"
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.\" Copyright (c) 1983, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)setuid.2 8.1 (Berkeley) 6/4/93
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.\"
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.Dd June 4, 1993
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.Dt SETUID 2
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.Os BSD 4.2
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.Sh NAME
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.Nm setegid ,
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.Nm seteuid ,
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.Nm setgid ,
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.Nm setuid
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.Nd set user and group ID
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.Sh SYNOPSIS
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.Fd #include <unistd.h>
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.Ft int
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.Fo setegid
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.Fa "gid_t egid"
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.Fc
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.Ft int
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.Fo seteuid
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.Fa "uid_t euid"
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.Fc
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.Ft int
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.Fo setgid
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.Fa "gid_t gid"
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.Fc
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.Ft int
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.Fo setuid
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.Fa "uid_t uid"
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.Fc
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.Sh DESCRIPTION
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The
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.Fn setuid
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function
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sets the real and effective
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user IDs and the saved set-user-ID of the current process
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to the specified value.
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The
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.Fn setuid
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function is permitted if the effective user ID is that of the super user,
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or if the specified user ID is the same as the effective user ID. If
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not, but the specified user ID is the same as the real user ID,
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.Fn setuid
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will set the effective user ID to the real user ID.
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.Pp
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The
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.Fn setgid
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function
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sets the real and effective
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group IDs and the saved set-group-ID of the current process
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to the specified value.
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The
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.Fn setgid
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function is permitted if the effective user ID is that of the super user,
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or if the specified group ID is the same as the effective group ID. If
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not, but the specified group ID is the same as the real group ID,
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.Fn setgid
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will set the effective group ID to the real group ID.
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.Pp
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The
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.Fn seteuid
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function
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.Pq Fn setegid
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sets the effective user ID (group ID) of the
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current process.
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The effective user ID may be set to the value
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of the real user ID or the saved set-user-ID (see
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.Xr intro 2
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and
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.Xr execve 2 ) ;
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in this way, the effective user ID of a set-user-ID executable
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may be toggled by switching to the real user ID, then re-enabled
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by reverting to the set-user-ID value.
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Similarly, the effective group ID may be set to the value
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of the real group ID or the saved set-group-ID.
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.Pp
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.Sh RETURN VALUES
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Upon success, these functions return 0;
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otherwise \-1 is returned.
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.Pp
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If the user is not the super user, or the uid
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specified is not the real, effective ID, or saved ID,
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these functions return \-1.
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.Pp
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.Sh ERRORS
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The
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.Fn setegid ,
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.Fn seteuid ,
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.Fn setgid ,
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and
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.Fn setuid
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system calls will fail if:
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.Bl -tag -width Er
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.\" ===========
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.It Bq Er EINVAL
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The value of the {group,user} ID argument is invalid
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and is not supported by the implementation.
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.\" ===========
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.It Bq Er EPERM
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The process does not have appropriate privileges and
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the ID argument
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does not match the real ID
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or the saved set-{group,user}-ID.
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.El
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.Sh LEGACY SYNOPSIS
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.Fd #include <sys/types.h>
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.Fd #include <unistd.h>
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.Pp
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The include file
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.In sys/types.h
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is necessary for all functions.
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.Sh SEE ALSO
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.Xr getgid 2 ,
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.Xr getuid 2 ,
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.Xr compat 5
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.Sh STANDARDS
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The
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.Fn setuid
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and
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.Fn setgid
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functions are compliant with the
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.St -p1003.1-90
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specification with
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.Li _POSIX_SAVED_IDS
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defined, with the extensions allowed in section B.4.2.2.
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The
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.Fn seteuid
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and
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.Fn setegid
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functions are extensions based on the
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.Tn POSIX
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concept of
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.Li _POSIX_SAVED_IDS ,
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and have been proposed for a future revision of the standard.
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