Home | History | Annotate | Line # | Download | only in util 
      1 /*	$NetBSD: set_eugid.c,v 1.2 2025/02/25 19:15:52 christos Exp $	*/
      2 
      3 /*++
      4 /* NAME
      5 /*	set_eugid 3
      6 /* SUMMARY
      7 /*	set effective user and group attributes
      8 /* SYNOPSIS
      9 /*	#include <set_eugid.h>
     10 /*
     11 /*	void	set_eugid(euid, egid)
     12 /*	uid_t	euid;
     13 /*	gid_t	egid;
     14 /*
     15 /*	void	SAVE_AND_SET_EUGID(uid, gid)
     16 /*	uid_t	uid;
     17 /*	gid_t gid;
     18 /*
     19 /*	void	RESTORE_SAVED_EUGID()
     20 /* DESCRIPTION
     21 /*	set_eugid() sets the effective user and group process attributes
     22 /*	and updates the process group access list to be just the specified
     23 /*	effective group id.
     24 /*
     25 /*	SAVE_AND_SET_EUGID() opens a block that executes with the
     26 /*	specified privilege. RESTORE_SAVED_EUGID() closes the block.
     27 /* DIAGNOSTICS
     28 /*	All system call errors are fatal.
     29 /* SEE ALSO
     30 /*	seteuid(2), setegid(2), setgroups(2)
     31 /* LICENSE
     32 /* .ad
     33 /* .fi
     34 /*	The Secure Mailer license must be distributed with this software.
     35 /* AUTHOR(S)
     36 /*	Wietse Venema
     37 /*	IBM T.J. Watson Research
     38 /*	P.O. Box 704
     39 /*	Yorktown Heights, NY 10598, USA
     40 /*--*/
     41 
     42 /* System library. */
     43 
     44 #include <sys_defs.h>
     45 #include <unistd.h>
     46 #include <grp.h>
     47 #include <errno.h>
     48 
     49 /* Utility library. */
     50 
     51 #include "msg.h"
     52 #include "set_eugid.h"
     53 
     54 /* set_eugid - set effective user and group attributes */
     55 
     56 void    set_eugid(uid_t euid, gid_t egid)
     57 {
     58     int     saved_errno = errno;
     59 
     60     if (geteuid() != 0)
     61 	if (seteuid(0))
     62 	    msg_fatal("set_eugid: seteuid(0): %m");
     63     if (setegid(egid) < 0)
     64 	msg_fatal("set_eugid: setegid(%ld): %m", (long) egid);
     65     if (setgroups(1, &egid) < 0)
     66 	msg_fatal("set_eugid: setgroups(%ld): %m", (long) egid);
     67     if (euid != 0 && seteuid(euid) < 0)
     68 	msg_fatal("set_eugid: seteuid(%ld): %m", (long) euid);
     69     if (msg_verbose)
     70 	msg_info("set_eugid: euid %ld egid %ld", (long) euid, (long) egid);
     71     errno = saved_errno;
     72 }
     73