467 lines
12 KiB
C
467 lines
12 KiB
C
/*
|
|
* Copyright (c) 1988 The Regents of the University of California.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include "bsd_locl.h"
|
|
|
|
RCSID ("$Id: su.c,v 1.66 1999/03/11 13:57:58 joda Exp $");
|
|
|
|
#ifdef SYSV_SHADOW
|
|
#include "sysv_shadow.h"
|
|
#endif
|
|
|
|
static int kerberos (char *username, char *user, int uid);
|
|
static int chshell (char *sh);
|
|
static char *ontty (void);
|
|
static int koktologin (char *name, char *realm, char *toname);
|
|
static int chshell (char *sh);
|
|
|
|
/* Handle '-' option after all the getopt options */
|
|
#define ARGSTR "Kflmi:"
|
|
|
|
static int use_kerberos = 1;
|
|
static char *root_inst = "root";
|
|
|
|
int
|
|
main (int argc, char **argv)
|
|
{
|
|
struct passwd *pwd;
|
|
char *p, **g;
|
|
struct group *gr;
|
|
uid_t ruid;
|
|
int asme, ch, asthem, fastlogin, prio;
|
|
enum { UNSET, YES, NO } iscsh = UNSET;
|
|
char *user, *shell, *avshell, *username, **np;
|
|
char shellbuf[MaxPathLen], avshellbuf[MaxPathLen];
|
|
|
|
set_progname (argv[0]);
|
|
|
|
asme = asthem = fastlogin = 0;
|
|
while ((ch = getopt (argc, argv, ARGSTR)) != EOF)
|
|
switch ((char) ch) {
|
|
case 'K':
|
|
use_kerberos = 0;
|
|
break;
|
|
case 'f':
|
|
fastlogin = 1;
|
|
break;
|
|
case 'l':
|
|
asme = 0;
|
|
asthem = 1;
|
|
break;
|
|
case 'm':
|
|
asme = 1;
|
|
asthem = 0;
|
|
break;
|
|
case 'i':
|
|
root_inst = optarg;
|
|
break;
|
|
case '?':
|
|
default:
|
|
fprintf (stderr,
|
|
"usage: su [-Kflm] [-i root-instance] [-] [login]\n");
|
|
exit (1);
|
|
}
|
|
/* Don't handle '-' option with getopt */
|
|
if (optind < argc && strcmp (argv[optind], "-") == 0) {
|
|
asme = 0;
|
|
asthem = 1;
|
|
optind++;
|
|
}
|
|
argv += optind;
|
|
|
|
if (use_kerberos) {
|
|
int fd = open (KEYFILE, O_RDONLY);
|
|
|
|
if (fd >= 0)
|
|
close (fd);
|
|
else
|
|
use_kerberos = 0;
|
|
}
|
|
errno = 0;
|
|
prio = getpriority (PRIO_PROCESS, 0);
|
|
if (errno)
|
|
prio = 0;
|
|
setpriority (PRIO_PROCESS, 0, -2);
|
|
openlog ("su", LOG_CONS, LOG_AUTH);
|
|
|
|
/* get current login name and shell */
|
|
ruid = getuid ();
|
|
username = getlogin ();
|
|
if (username == NULL || (pwd = k_getpwnam (username)) == NULL ||
|
|
pwd->pw_uid != ruid)
|
|
pwd = k_getpwuid (ruid);
|
|
if (pwd == NULL)
|
|
errx (1, "who are you?");
|
|
username = strdup (pwd->pw_name);
|
|
if (username == NULL)
|
|
errx (1, "strdup: out of memory");
|
|
if (asme) {
|
|
if (pwd->pw_shell && *pwd->pw_shell) {
|
|
strcpy_truncate (shellbuf, pwd->pw_shell, sizeof(shellbuf));
|
|
shell = shellbuf;
|
|
} else {
|
|
shell = _PATH_BSHELL;
|
|
iscsh = NO;
|
|
}
|
|
}
|
|
|
|
/* get target login information, default to root */
|
|
user = *argv ? *argv : "root";
|
|
np = *argv ? argv : argv - 1;
|
|
|
|
pwd = k_getpwnam (user);
|
|
if (pwd == NULL)
|
|
errx (1, "unknown login %s", user);
|
|
if (pwd->pw_uid == 0 && strcmp ("root", user) != 0) {
|
|
syslog (LOG_ALERT, "NIS attack, user %s has uid 0", user);
|
|
errx (1, "unknown login %s", user);
|
|
}
|
|
if (!use_kerberos || kerberos (username, user, pwd->pw_uid)) {
|
|
#ifndef PASSWD_FALLBACK
|
|
errx (1, "won't use /etc/passwd authentication");
|
|
#endif
|
|
/* getpwnam() is not reentrant and kerberos might use it! */
|
|
pwd = k_getpwnam (user);
|
|
if (pwd == NULL)
|
|
errx (1, "unknown login %s", user);
|
|
/* only allow those in group zero to su to root. */
|
|
if (pwd->pw_uid == 0 && (gr = getgrgid ((gid_t) 0)))
|
|
for (g = gr->gr_mem;; ++g) {
|
|
if (!*g) {
|
|
#if 1
|
|
/* if group 0 is empty or only
|
|
contains root su is still ok. */
|
|
if (gr->gr_mem[0] == 0)
|
|
break; /* group 0 is empty */
|
|
if (gr->gr_mem[1] == 0 &&
|
|
strcmp (gr->gr_mem[0], "root") == 0)
|
|
break; /* only root in group 0 */
|
|
#endif
|
|
errx (1, "you are not in the correct group to su %s.",
|
|
user);
|
|
}
|
|
if (!strcmp (username, *g))
|
|
break;
|
|
}
|
|
/* if target requires a password, verify it */
|
|
if (ruid && *pwd->pw_passwd) {
|
|
char prompt[128];
|
|
char passwd[256];
|
|
|
|
snprintf (prompt, sizeof(prompt), "%s's Password: ", pwd->pw_name);
|
|
if (des_read_pw_string (passwd, sizeof (passwd),
|
|
prompt, 0)) {
|
|
memset (passwd, 0, sizeof (passwd));
|
|
exit (1);
|
|
}
|
|
if (strcmp (pwd->pw_passwd,
|
|
crypt (passwd, pwd->pw_passwd))) {
|
|
memset (passwd, 0, sizeof (passwd));
|
|
syslog (LOG_AUTH | LOG_WARNING,
|
|
"BAD SU %s to %s%s", username,
|
|
user, ontty ());
|
|
errx (1, "Sorry");
|
|
}
|
|
memset (passwd, 0, sizeof (passwd));
|
|
}
|
|
}
|
|
if (asme) {
|
|
/* if asme and non-standard target shell, must be root */
|
|
if (!chshell (pwd->pw_shell) && ruid)
|
|
errx (1, "permission denied (shell '%s' not in /etc/shells).",
|
|
pwd->pw_shell);
|
|
} else if (pwd->pw_shell && *pwd->pw_shell) {
|
|
shell = pwd->pw_shell;
|
|
iscsh = UNSET;
|
|
} else {
|
|
shell = _PATH_BSHELL;
|
|
iscsh = NO;
|
|
}
|
|
|
|
if ((p = strrchr (shell, '/')) != 0)
|
|
avshell = p + 1;
|
|
else
|
|
avshell = shell;
|
|
|
|
/* if we're forking a csh, we want to slightly muck the args */
|
|
if (iscsh == UNSET)
|
|
iscsh = strcmp (avshell, "csh") ? NO : YES;
|
|
|
|
/* set permissions */
|
|
|
|
if (setgid (pwd->pw_gid) < 0)
|
|
err (1, "setgid");
|
|
if (initgroups (user, pwd->pw_gid))
|
|
errx (1, "initgroups failed.");
|
|
|
|
if (setuid (pwd->pw_uid) < 0)
|
|
err (1, "setuid");
|
|
|
|
if (!asme) {
|
|
if (asthem) {
|
|
char *k = getenv ("KRBTKFILE");
|
|
char *t = getenv ("TERM");
|
|
|
|
environ = malloc (10 * sizeof (char *));
|
|
if (environ == NULL)
|
|
err (1, "malloc");
|
|
environ[0] = NULL;
|
|
setenv ("PATH", _PATH_DEFPATH, 1);
|
|
if (t)
|
|
setenv ("TERM", t, 1);
|
|
if (k)
|
|
setenv ("KRBTKFILE", k, 1);
|
|
if (chdir (pwd->pw_dir) < 0)
|
|
errx (1, "no directory");
|
|
}
|
|
if (asthem || pwd->pw_uid)
|
|
setenv ("USER", pwd->pw_name, 1);
|
|
setenv ("HOME", pwd->pw_dir, 1);
|
|
setenv ("SHELL", shell, 1);
|
|
}
|
|
if (iscsh == YES) {
|
|
if (fastlogin)
|
|
*np-- = "-f";
|
|
if (asme)
|
|
*np-- = "-m";
|
|
}
|
|
if (asthem) {
|
|
snprintf (avshellbuf, sizeof(avshellbuf),
|
|
"-%s", avshell);
|
|
avshell = avshellbuf;
|
|
} else if (iscsh == YES) {
|
|
/* csh strips the first character... */
|
|
snprintf (avshellbuf, sizeof(avshellbuf),
|
|
"_%s", avshell);
|
|
avshell = avshellbuf;
|
|
}
|
|
*np = avshell;
|
|
|
|
if (ruid != 0)
|
|
syslog (LOG_NOTICE | LOG_AUTH, "%s to %s%s",
|
|
username, user, ontty ());
|
|
|
|
setpriority (PRIO_PROCESS, 0, prio);
|
|
|
|
if (k_hasafs ()) {
|
|
int code;
|
|
|
|
if (k_setpag () != 0)
|
|
warn ("setpag");
|
|
code = krb_afslog (0, 0);
|
|
if (code != KSUCCESS && code != KDC_PR_UNKNOWN)
|
|
warnx ("afsklog: %s", krb_get_err_text (code));
|
|
}
|
|
execv (shell, np);
|
|
warn ("execv(%s)", shell);
|
|
if (getuid () == 0) {
|
|
execv (_PATH_BSHELL, np);
|
|
warn ("execv(%s)", _PATH_BSHELL);
|
|
}
|
|
exit (1);
|
|
}
|
|
|
|
static int
|
|
chshell (char *sh)
|
|
{
|
|
char *cp;
|
|
|
|
while ((cp = getusershell ()) != NULL)
|
|
if (!strcmp (cp, sh))
|
|
return (1);
|
|
return (0);
|
|
}
|
|
|
|
static char *
|
|
ontty (void)
|
|
{
|
|
char *p;
|
|
static char buf[MaxPathLen + 4];
|
|
|
|
buf[0] = 0;
|
|
if ((p = ttyname (STDERR_FILENO)) != 0)
|
|
snprintf (buf, sizeof(buf), " on %s", p);
|
|
return (buf);
|
|
}
|
|
|
|
static int
|
|
kerberos (char *username, char *user, int uid)
|
|
{
|
|
KTEXT_ST ticket;
|
|
AUTH_DAT authdata;
|
|
struct hostent *hp;
|
|
int kerno;
|
|
u_long faddr;
|
|
char lrealm[REALM_SZ], krbtkfile[MaxPathLen];
|
|
char hostname[MaxHostNameLen], savehost[MaxHostNameLen];
|
|
|
|
if (krb_get_lrealm (lrealm, 1) != KSUCCESS)
|
|
return (1);
|
|
if (koktologin (username, lrealm, user) && !uid) {
|
|
#ifndef PASSWD_FALLBACK
|
|
warnx ("not in %s's ACL.", user);
|
|
#endif
|
|
return (1);
|
|
}
|
|
snprintf (krbtkfile, sizeof(krbtkfile),
|
|
"%s_%s_to_%s_%u", TKT_ROOT, username, user,
|
|
(unsigned) getpid ());
|
|
|
|
setenv ("KRBTKFILE", krbtkfile, 1);
|
|
krb_set_tkt_string (krbtkfile);
|
|
/*
|
|
* Set real as well as effective ID to 0 for the moment,
|
|
* to make the kerberos library do the right thing.
|
|
*/
|
|
if (setuid(0) < 0) {
|
|
warn("setuid");
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* Little trick here -- if we are su'ing to root, we need to get a ticket
|
|
* for "xxx.root", where xxx represents the name of the person su'ing.
|
|
* Otherwise (non-root case), we need to get a ticket for "yyy.", where
|
|
* yyy represents the name of the person being su'd to, and the instance
|
|
* is null
|
|
*
|
|
* We should have a way to set the ticket lifetime, with a system default
|
|
* for root.
|
|
*/
|
|
{
|
|
char prompt[128];
|
|
char passw[256];
|
|
|
|
snprintf (prompt, sizeof(prompt),
|
|
"%s's Password: ",
|
|
krb_unparse_name_long ((uid == 0 ? username : user),
|
|
(uid == 0 ? root_inst : ""),
|
|
lrealm));
|
|
if (des_read_pw_string (passw, sizeof (passw), prompt, 0)) {
|
|
memset (passw, 0, sizeof (passw));
|
|
return (1);
|
|
}
|
|
if (strlen(passw) == 0)
|
|
return (1); /* Empty passwords is not allowed */
|
|
kerno = krb_get_pw_in_tkt ((uid == 0 ? username : user),
|
|
(uid == 0 ? root_inst : ""), lrealm,
|
|
KRB_TICKET_GRANTING_TICKET,
|
|
lrealm,
|
|
DEFAULT_TKT_LIFE,
|
|
passw);
|
|
memset (passw, 0, strlen (passw));
|
|
}
|
|
|
|
if (kerno != KSUCCESS) {
|
|
if (kerno == KDC_PR_UNKNOWN) {
|
|
warnx ("principal unknown: %s",
|
|
krb_unparse_name_long ((uid == 0 ? username : user),
|
|
(uid == 0 ? root_inst : ""),
|
|
lrealm));
|
|
return (1);
|
|
}
|
|
warnx ("unable to su: %s", krb_get_err_text (kerno));
|
|
syslog (LOG_NOTICE | LOG_AUTH,
|
|
"BAD SU: %s to %s%s: %s",
|
|
username, user, ontty (), krb_get_err_text (kerno));
|
|
return (1);
|
|
}
|
|
if (chown (krbtkfile, uid, -1) < 0) {
|
|
warn ("chown");
|
|
unlink (krbtkfile);
|
|
return (1);
|
|
}
|
|
setpriority (PRIO_PROCESS, 0, -2);
|
|
|
|
if (gethostname (hostname, sizeof (hostname)) == -1) {
|
|
warn ("gethostname");
|
|
dest_tkt ();
|
|
return (1);
|
|
}
|
|
strcpy_truncate (savehost, krb_get_phost (hostname), sizeof (savehost));
|
|
|
|
kerno = krb_mk_req (&ticket, "rcmd", savehost, lrealm, 33);
|
|
|
|
if (kerno == KDC_PR_UNKNOWN) {
|
|
warnx ("Warning: TGT not verified.");
|
|
syslog (LOG_NOTICE | LOG_AUTH,
|
|
"%s to %s%s, TGT not verified (%s); "
|
|
"%s.%s not registered?",
|
|
username, user, ontty (), krb_get_err_text (kerno),
|
|
"rcmd", savehost);
|
|
#ifdef KLOGIN_PARANOID
|
|
/*
|
|
* if the "VERIFY_SERVICE" doesn't exist in the KDC for this host, *
|
|
* don't allow kerberos login, also log the error condition.
|
|
*/
|
|
warnx ("Trying local password!");
|
|
return (1);
|
|
#endif
|
|
} else if (kerno != KSUCCESS) {
|
|
warnx ("Unable to use TGT: %s", krb_get_err_text (kerno));
|
|
syslog (LOG_NOTICE | LOG_AUTH, "failed su: %s to %s%s: %s",
|
|
username, user, ontty (), krb_get_err_text (kerno));
|
|
dest_tkt ();
|
|
return (1);
|
|
} else {
|
|
if (!(hp = gethostbyname (hostname))) {
|
|
warnx ("can't get addr of %s", hostname);
|
|
dest_tkt ();
|
|
return (1);
|
|
}
|
|
memcpy (&faddr, hp->h_addr, sizeof (faddr));
|
|
|
|
if ((kerno = krb_rd_req (&ticket, "rcmd", savehost, faddr,
|
|
&authdata, "")) != KSUCCESS) {
|
|
warnx ("unable to verify rcmd ticket: %s",
|
|
krb_get_err_text (kerno));
|
|
syslog (LOG_NOTICE | LOG_AUTH,
|
|
"failed su: %s to %s%s: %s", username,
|
|
user, ontty (), krb_get_err_text (kerno));
|
|
dest_tkt ();
|
|
return (1);
|
|
}
|
|
}
|
|
fprintf (stderr, "Don't forget to kdestroy before exiting the shell.\n");
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
koktologin (char *name, char *realm, char *toname)
|
|
{
|
|
return krb_kuserok (name,
|
|
strcmp (toname, "root") == 0 ? root_inst : "",
|
|
realm,
|
|
toname);
|
|
}
|