410 lines
10 KiB
C
410 lines
10 KiB
C
/*
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* Copyright (c) 1988, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char copyright[] =
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"@(#) Copyright (c) 1988, 1993, 1994\n\
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The Regents of the University of California. All rights reserved.\n";
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#endif /* not lint */
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#ifndef lint
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static char sccsid[] = "@(#)su.c 8.3 (Berkeley) 4/2/94";
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#endif /* not lint */
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#include <sys/param.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <err.h>
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#include <errno.h>
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#include <grp.h>
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#include <paths.h>
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#include <pwd.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <syslog.h>
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#include <unistd.h>
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#ifdef SKEY
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#include <skey.h>
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#endif
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#ifdef KERBEROS
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#include <kerberosIV/des.h>
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#include <kerberosIV/krb.h>
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#include <netdb.h>
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#define ARGSTR "-Kflm"
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int use_kerberos = 1;
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#else
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#define ARGSTR "-flm"
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#endif
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char *ontty __P((void));
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int chshell __P((char *));
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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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extern char **environ;
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struct passwd *pwd;
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char *p, **g, *user, *shell, *username, *cleanenv[20], *nargv[4], **np;
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struct group *gr;
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uid_t ruid;
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int asme, ch, asthem, fastlogin, prio;
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enum { UNSET, YES, NO } iscsh = UNSET;
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char shellbuf[MAXPATHLEN];
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np = &nargv[3];
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*np-- = NULL;
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asme = asthem = fastlogin = 0;
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while ((ch = getopt(argc, argv, ARGSTR)) != EOF)
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switch((char)ch) {
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#ifdef KERBEROS
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case 'K':
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use_kerberos = 0;
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break;
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#endif
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case 'f':
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fastlogin = 1;
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break;
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case '-':
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case 'l':
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asme = 0;
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asthem = 1;
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break;
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case 'm':
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asme = 1;
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asthem = 0;
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break;
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case '?':
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default:
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(void)fprintf(stderr, "usage: su [%s] [login]\n",
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ARGSTR);
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exit(1);
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}
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argv += optind;
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errno = 0;
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prio = getpriority(PRIO_PROCESS, 0);
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if (errno)
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prio = 0;
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(void)setpriority(PRIO_PROCESS, 0, -2);
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openlog("su", LOG_CONS, 0);
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/* get current login name and shell */
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ruid = getuid();
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username = getlogin();
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if (username == NULL || (pwd = getpwnam(username)) == NULL ||
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pwd->pw_uid != ruid)
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pwd = getpwuid(ruid);
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if (pwd == NULL)
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errx(1, "who are you?");
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username = strdup(pwd->pw_name);
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if (username == NULL)
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err(1, NULL);
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if (asme)
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if (pwd->pw_shell && *pwd->pw_shell)
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shell = strcpy(shellbuf, pwd->pw_shell);
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else {
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shell = _PATH_BSHELL;
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iscsh = NO;
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}
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/* get target login information, default to root */
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user = *argv ? *argv : "root";
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if ((pwd = getpwnam(user)) == NULL) {
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fprintf(stderr, "su: unknown login %s\n", user);
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exit(1);
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}
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if (ruid) {
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#ifdef KERBEROS
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if (!use_kerberos || kerberos(username, user, pwd->pw_uid))
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#endif
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{
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/* only allow those in group zero to su to root. */
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if (pwd->pw_uid == 0 && (gr = getgrgid((gid_t)0)))
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for (g = gr->gr_mem;; ++g) {
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if (!*g)
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errx(1,
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"you are not in the correct group to su %s.",
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user);
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if (strcmp(username, *g) == 0)
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break;
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}
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/* if target requires a password, verify it */
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if (*pwd->pw_passwd) {
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#ifdef SKEY
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p = skey_getpass("Password:", pwd, 1);
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if (strcmp(pwd->pw_passwd,
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skey_crypt(p, pwd->pw_passwd, pwd, 1))) {
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#else
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p = getpass("Password:");
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if (strcmp(pwd->pw_passwd, crypt(p, pwd->pw_passwd))) {
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#endif
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fprintf(stderr, "Sorry\n");
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syslog(LOG_AUTH|LOG_WARNING,
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"BAD SU %s to %s%s", username,
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user, ontty());
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exit(1);
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}
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}
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}
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}
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if (asme) {
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/* if asme and non-standard target shell, must be root */
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if (!chshell(pwd->pw_shell) && ruid)
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errx(1, "permission denied (shell).");
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} else if (pwd->pw_shell && *pwd->pw_shell) {
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shell = pwd->pw_shell;
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iscsh = UNSET;
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} else {
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shell = _PATH_BSHELL;
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iscsh = NO;
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}
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/* if we're forking a csh, we want to slightly muck the args */
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if (iscsh == UNSET) {
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if (p = strrchr(shell, '/'))
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++p;
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else
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p = shell;
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iscsh = strcmp(p, "csh") ? NO : YES;
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}
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/* set permissions */
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if (setgid(pwd->pw_gid) < 0)
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err(1, "setgid");
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if (initgroups(user, pwd->pw_gid))
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errx(1, "initgroups failed");
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if (setuid(pwd->pw_uid) < 0)
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err(1, "setuid");
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if (!asme) {
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if (asthem) {
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p = getenv("TERM");
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cleanenv[0] = NULL;
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environ = cleanenv;
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(void)setenv("PATH", _PATH_DEFPATH, 1);
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(void)setenv("TERM", p, 1);
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if (chdir(pwd->pw_dir) < 0)
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errx(1, "no directory");
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}
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if (asthem || pwd->pw_uid)
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(void)setenv("USER", pwd->pw_name, 1);
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(void)setenv("HOME", pwd->pw_dir, 1);
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(void)setenv("SHELL", shell, 1);
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}
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if (iscsh == YES) {
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if (fastlogin)
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*np-- = "-f";
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if (asme)
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*np-- = "-m";
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}
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/* csh strips the first character... */
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*np = asthem ? "-su" : iscsh == YES ? "_su" : "su";
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if (ruid != 0)
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syslog(LOG_NOTICE|LOG_AUTH, "%s to %s%s",
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username, user, ontty());
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(void)setpriority(PRIO_PROCESS, 0, prio);
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execv(shell, np);
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err(1, "%s", shell);
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}
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int
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chshell(sh)
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char *sh;
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{
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char *cp;
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while ((cp = getusershell()) != NULL)
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if (strcmp(cp, sh) == 0)
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return (1);
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return (0);
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}
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char *
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ontty()
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{
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char *p;
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static char buf[MAXPATHLEN + 4];
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buf[0] = 0;
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if (p = ttyname(STDERR_FILENO))
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snprintf(buf, sizeof(buf), " on %s", p);
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return (buf);
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}
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#ifdef KERBEROS
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kerberos(username, user, uid)
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char *username, *user;
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int uid;
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{
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extern char *krb_err_txt[];
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KTEXT_ST ticket;
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AUTH_DAT authdata;
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struct hostent *hp;
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char *p;
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int kerno;
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u_long faddr;
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char lrealm[REALM_SZ], krbtkfile[MAXPATHLEN];
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char hostname[MAXHOSTNAMELEN], savehost[MAXHOSTNAMELEN];
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char *krb_get_phost();
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if (krb_get_lrealm(lrealm, 1) != KSUCCESS)
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return (1);
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if (koktologin(username, lrealm, user) && !uid) {
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warnx("kerberos: not in %s's ACL.", user);
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return (1);
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}
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(void)sprintf(krbtkfile, "%s_%s_%d", TKT_ROOT, user, getuid());
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(void)setenv("KRBTKFILE", krbtkfile, 1);
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(void)krb_set_tkt_string(krbtkfile);
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/*
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* Set real as well as effective ID to 0 for the moment,
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* to make the kerberos library do the right thing.
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*/
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if (setuid(0) < 0) {
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warn("setuid");
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return (1);
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}
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/*
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* Little trick here -- if we are su'ing to root,
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* we need to get a ticket for "xxx.root", where xxx represents
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* the name of the person su'ing. Otherwise (non-root case),
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* we need to get a ticket for "yyy.", where yyy represents
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* the name of the person being su'd to, and the instance is null
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*
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* We should have a way to set the ticket lifetime,
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* with a system default for root.
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*/
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kerno = krb_get_pw_in_tkt((uid == 0 ? username : user),
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(uid == 0 ? "root" : ""), lrealm,
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"krbtgt", lrealm, DEFAULT_TKT_LIFE, 0);
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if (kerno != KSUCCESS) {
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if (kerno == KDC_PR_UNKNOWN) {
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warnx("kerberos: principal unknown: %s.%s@%s",
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(uid == 0 ? username : user),
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(uid == 0 ? "root" : ""), lrealm);
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return (1);
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}
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warnx("kerberos: unable to su: %s", krb_err_txt[kerno]);
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syslog(LOG_NOTICE|LOG_AUTH,
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"BAD Kerberos SU: %s to %s%s: %s",
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username, user, ontty(), krb_err_txt[kerno]);
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return (1);
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}
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if (chown(krbtkfile, uid, -1) < 0) {
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warn("chown");
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(void)unlink(krbtkfile);
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return (1);
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}
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(void)setpriority(PRIO_PROCESS, 0, -2);
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if (gethostname(hostname, sizeof(hostname)) == -1) {
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warn("gethostname");
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dest_tkt();
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return (1);
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}
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(void)strncpy(savehost, krb_get_phost(hostname), sizeof(savehost));
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savehost[sizeof(savehost) - 1] = '\0';
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kerno = krb_mk_req(&ticket, "rcmd", savehost, lrealm, 33);
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if (kerno == KDC_PR_UNKNOWN) {
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warnx("Warning: TGT not verified.");
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syslog(LOG_NOTICE|LOG_AUTH,
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"%s to %s%s, TGT not verified (%s); %s.%s not registered?",
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username, user, ontty(), krb_err_txt[kerno],
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"rcmd", savehost);
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} else if (kerno != KSUCCESS) {
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warnx("Unable to use TGT: %s", krb_err_txt[kerno]);
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syslog(LOG_NOTICE|LOG_AUTH, "failed su: %s to %s%s: %s",
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username, user, ontty(), krb_err_txt[kerno]);
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dest_tkt();
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return (1);
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} else {
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if (!(hp = gethostbyname(hostname))) {
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warnx("can't get addr of %s", hostname);
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dest_tkt();
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return (1);
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}
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memmove((char *)&faddr, (char *)hp->h_addr, sizeof(faddr));
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if ((kerno = krb_rd_req(&ticket, "rcmd", savehost, faddr,
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&authdata, "")) != KSUCCESS) {
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warnx("kerberos: unable to verify rcmd ticket: %s\n",
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krb_err_txt[kerno]);
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syslog(LOG_NOTICE|LOG_AUTH,
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"failed su: %s to %s%s: %s", username,
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user, ontty(), krb_err_txt[kerno]);
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dest_tkt();
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return (1);
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}
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}
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return (0);
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}
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koktologin(name, realm, toname)
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char *name, *realm, *toname;
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{
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AUTH_DAT *kdata;
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AUTH_DAT kdata_st;
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kdata = &kdata_st;
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memset((char *)kdata, 0, sizeof(*kdata));
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(void)strcpy(kdata->pname, name);
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(void)strcpy(kdata->pinst,
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((strcmp(toname, "root") == 0) ? "root" : ""));
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(void)strcpy(kdata->prealm, realm);
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return (kuserok(kdata, toname));
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}
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#endif
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