2004-11-03 13:51:07 +00:00
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.\" Copyright (C) 2001 Andries Brouwer (aeb@cwi.nl)
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" [should really be seteuid.3]
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2004-11-03 14:43:40 +00:00
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.\" Modified, 27 May 2004, Michael Kerrisk <mtk-manpages@gmx.net>
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2004-11-03 13:51:07 +00:00
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.\" Added notes on capability requirements
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.\"
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.TH SETEGID 2 2004-05-27 "Linux 2.6.6" "Linux Programmer's Manual"
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.SH NAME
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seteuid, setegid \- set effective user or group ID
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.SH SYNOPSIS
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.B #include <sys/types.h>
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.br
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.B #include <unistd.h>
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.sp
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.BI "int seteuid(uid_t " euid );
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.br
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.BI "int setegid(gid_t " egid );
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.SH DESCRIPTION
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.B seteuid
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sets the effective user ID of the current process.
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Unprivileged user processes may only set the effective user ID to the
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real user ID, the effective user ID or the saved user ID.
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Precisely the same holds for
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.B setegid
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with "group" instead of "user".
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.\" When
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.\" .I euid
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.\" equals \-1, nothing is changed.
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.SH "RETURN VALUE"
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On success, zero is returned. On error, \-1 is returned, and
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.I errno
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is set appropriately.
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.SH ERRORS
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.\" .TP
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.\" .B EINVAL
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.TP
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.B EPERM
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The current process is not privileged (Linux: does not have the
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.B CAP_SETUID
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capability in the case of
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.BR seteuid (),
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or the
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.B CAP_SETGID
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capability in the case of
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.BR setegid ())
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and
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.I euid
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(resp.
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.IR egid )
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is not the real user (group) ID, the effective user (group) ID
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or the saved user (group) ID.
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.SH NOTES
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Setting the effective user (group) ID to the saved user (group) ID is
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possible since Linux 1.1.37 (1.1.38).
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On an arbitrary system one should check _POSIX_SAVED_IDS.
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.LP
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Under libc4, libc5 and glibc2.0
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.BI seteuid( euid )
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is equivalent to
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2005-07-06 12:57:38 +00:00
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.BI setreuid(\-1, " euid" )
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2004-11-03 13:51:07 +00:00
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and hence may change the saved user ID.
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Under glibc2.1 it is equivalent to
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2005-07-06 12:57:38 +00:00
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.BI setresuid(\-1, " euid" ,\-1)
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2004-11-03 13:51:07 +00:00
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and hence does not change the saved user ID.
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Similar remarks hold for
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.BR setegid .
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.SH "CONFORMING TO"
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2005-07-18 15:05:56 +00:00
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4.3BSD
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2004-11-03 13:51:07 +00:00
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.SH "SEE ALSO"
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.BR geteuid (2),
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.BR setresuid (2),
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.BR setreuid (2),
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.BR setuid (2),
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.BR capabilities (7)
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