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/*
* Copyright (c) 2001 Sendmail, Inc. and its suppliers.
* All rights reserved.
*
* By using this file, you agree to the terms and conditions set
* forth in the LICENSE file which can be found at the top level of
* the sendmail distribution.
*
*/
/*
** This program checks to see if your version of setgid works.
** Compile it, make it set-group-ID guest, and run it as yourself (NOT as
** root and not as member of the group guest).
**
** Compilation is trivial -- just "cc t_dropgid.c". Make it set-group-ID
** guest and then execute it as a non-root user.
*/
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#ifndef lint
static char id[] = "@(#)$Id: t_dropgid.c,v 1.6 2001/09/28 16:36:28 ca Exp $";
#endif /* ! lint */
static void
printgids(str, r, e)
char *str;
gid_t r, e;
{
printf("%s (should be %d/%d): r/egid=%d/%d\n", str, (int) r, (int) e,
(int) getgid(), (int) getegid());
}
/* define only one of these */
#if HASSETEGID
# define SETGIDCALL "setegid"
#endif /* HASSETEGID */
#if HASSETREGID
# define SETGIDCALL "setregid"
#endif /* HASSETREGID */
#if HASSETRESGID
# define SETGIDCALL "setresgid"
#endif /* HASSETRESGID */
#ifndef SETGIDCALL
# define SETGIDCALL "setgid"
#endif /* ! SETGIDCALL */
int
main(argc, argv)
int argc;
char **argv;
{
int fail = 0;
int res;
gid_t realgid = getgid();
gid_t effgid = getegid();
char *prg = argv[0];
printgids("initial gids", realgid, effgid);
if (effgid == realgid)
{
printf("SETUP ERROR: re-run set-group-ID guest\n");
printf("Use chgrp(1) and chmod(1)\n");
printf("For example, do this as root ");
printf("(nobody is the name of a group in this example):\n");
printf("# chgrp nobody %s\n", prg);
printf("# chmod g+s nobody %s\n", prg);
exit(1);
}
#if HASSETREGID
res = setregid(realgid, realgid);
printf("setregid(%d)=%d %s\n", (int) realgid, res,
res < 0 ? "failure" : "ok");
printgids("after setregid()", realgid, realgid);
#endif /* HASSETREGID */
#if HASSETRESGID
res = setresgid(realgid, realgid, realgid);
printf("setresgid(%d)=%d %s\n", (int) realgid, res,
res < 0 ? "failure" : "ok");
printgids("after setresgid()", realgid, realgid);
#endif /* HASSETRESGID */
#if HASSETEGID
res = setegid(realgid);
printf("setegid(%d)=%d %s\n", (int) realgid, res,
res < 0 ? "failure" : "ok");
printgids("after setegid()", realgid, realgid);
#endif /* HASSETEGID */
res = setgid(realgid);
printf("setgid(%d)=%d %s\n", (int) realgid, res,
res < 0 ? "failure" : "ok");
printgids("after setgid()", realgid, realgid);
if (getegid() != realgid)
{
fail++;
printf("MAYDAY! Wrong effective gid\n");
}
if (getgid() != realgid)
{
fail++;
printf("MAYDAY! Wrong real gid\n");
}
/* do activity here */
if (setgid(effgid) == 0)
{
fail++;
printf("MAYDAY! setgid(%d) succeeded (should have failed)\n",
effgid);
}
else
{
printf("setgid(%d) failed (this is correct)\n", effgid);
}
printgids("after setgid() to egid", realgid, realgid);
if (getegid() != realgid)
{
fail++;
printf("MAYDAY! Wrong effective gid\n");
}
if (getgid() != realgid)
{
fail++;
printf("MAYDAY! Wrong real gid\n");
}
printf("\n");
if (fail > 0)
{
printf("\nThis system cannot use %s to give up set-group-ID rights\n",
SETGIDCALL);
#if !HASSETEGID
printf("Maybe compile with -DHASSETEGID and try again\n");
#endif /* !HASSETEGID */
#if !HASSETREGID
printf("Maybe compile with -DHASSETREGID and try again\n");
#endif /* !HASSETREGID */
#if !HASSETRESGID
printf("Maybe compile with -DHASSETRESGID and try again\n");
#endif /* !HASSETRESGID */
exit(1);
}
printf("\nIt is possible to use %s on this system\n", SETGIDCALL);
exit(0);
}
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