99 lines
3.4 KiB
Groff
99 lines
3.4 KiB
Groff
.\" $OpenBSD: issetugid.2,v 1.7 1997/02/18 00:16:09 deraadt Exp $
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.\"
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.\" Copyright (c) 1980, 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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.\" 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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.\" $FreeBSD$
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.\"
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.Dd August 25, 1996
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.Dt ISSETUGID 2
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.Os
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.Sh NAME
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.Nm issetugid
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.Nd is current process tainted by uid or gid changes
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In unistd.h
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.Ft int
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.Fn issetugid void
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.Sh DESCRIPTION
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The
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.Fn issetugid
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system call returns 1 if the process environment or memory address space
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is considered
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.Dq tainted ,
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and returns 0 otherwise.
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.Pp
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A process is tainted if it was created as a result of an
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.Xr execve 2
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system call which had either of the setuid or setgid bits set (and extra
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privileges were given as a result) or if it has changed any of its real,
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effective or saved user or group ID's since it began execution.
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.Pp
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This system call exists so that library routines (eg: libc, libtermcap)
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can reliably determine if it is safe to use information
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that was obtained from the user, in particular the results from
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.Xr getenv 3
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should be viewed with suspicion if it is used to control operation.
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.Pp
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A
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.Dq tainted
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status is inherited by child processes as a result of the
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.Xr fork 2
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system call (or other library code that calls fork, such as
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.Xr popen 3 ) .
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.Pp
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It is assumed that a program that clears all privileges as it prepares
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to execute another will also reset the environment, hence the
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.Dq tainted
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status will not be passed on.
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This is important for programs such as
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.Xr su 1
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which begin setuid but need to be able to create an untainted process.
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.Sh ERRORS
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The
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.Fn issetugid
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system call is always successful, and no return value is reserved to
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indicate an error.
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.Sh SEE ALSO
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.Xr execve 2 ,
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.Xr fork 2 ,
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.Xr setegid 2 ,
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.Xr seteuid 2 ,
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.Xr setgid 2 ,
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.Xr setregid 2 ,
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.Xr setreuid 2 ,
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.Xr setuid 2
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.Sh HISTORY
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The
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.Fn issetugid
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system call first appeared in
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.Ox 2.0
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and was also implemented in
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.Fx 3.0 .
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