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