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      1 /*	$NetBSD: privs.h,v 1.10 2016/03/13 00:33:12 dholland Exp $	*/
      2 
      3 /*
      4  *  privs.h - header for privileged operations
      5  *  Copyright (C) 1993  Thomas Koenig
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. The name of the author(s) may not be used to endorse or promote
     13  *    products derived from this software without specific prior written
     14  *    permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     23  * THEORY OF LIABILITY, WETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  *
     27  * From: OpenBSD: privs.h,v 1.4 1997/03/01 23:40:12 millert Exp
     28  */
     29 
     30 #ifndef _PRIVS_H_
     31 #define _PRIVS_H_
     32 
     33 /*
     34  * Used by: usr.bin/at
     35  * Used by: libexec/atrun
     36  */
     37 
     38 /*
     39  * Relinquish privileges temporarily for a setuid or setgid program
     40  * with the option of getting them back later.  This is done by
     41  * using POSIX saved user and groups ids.  Call RELINQUISH_PRIVS once
     42  * at the beginning of the main program.  This will cause all operations
     43  * to be executed with the real userid.  When you need the privileges
     44  * of the setuid/setgid invocation, call PRIV_START; when you no longer
     45  * need it, call PRIV_END.  Note that it is an error to call PRIV_START
     46  * and not PRIV_END within the same function.
     47  *
     48  * Use RELINQUISH_PRIVS_ROOT(a,b) if your program started out running
     49  * as root, and you want to drop back the effective userid to a
     50  * and the effective group id to b, with the option to get them back
     51  * later.
     52  *
     53  * Problems: Do not use return between PRIV_START and PRIV_END; this
     54  * will cause the program to continue running in an unprivileged
     55  * state.
     56  *
     57  * It is NOT safe to call exec(), system() or popen() with a user-
     58  * supplied program (i.e. without carefully checking PATH and any
     59  * library load paths) with relinquished privileges; the called program
     60  * can acquire them just as easily.  Set both effective and real userid
     61  * to the real userid before calling any of them.
     62  */
     63 
     64 extern uid_t real_uid, effective_uid;
     65 extern gid_t real_gid, effective_gid;
     66 
     67 void privs_relinquish(void);
     68 void privs_relinquish_root(uid_t ruid, gid_t rgid);
     69 
     70 void privs_enter(void);
     71 void privs_exit(void);
     72 
     73 /* caller provides this */
     74 __dead void privs_fail(const char *msg);
     75 
     76 #endif /* _PRIV_H_ */
     77