mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2024-12-24 19:21:38 +01:00
99005ad98e
to su to root by authenticating as themselves (using a password or S/Key) rather than by using the root password. This is useful in contexts like ours, where a large group of people need root access to a set of machines. (However, the security implications are such that this should not be enabled by default.) The code is conditionalized on WHEELSU.
441 lines
11 KiB
C
441 lines
11 KiB
C
/*
|
|
* Copyright (c) 1988, 1993, 1994
|
|
* 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.
|
|
*/
|
|
|
|
#ifndef lint
|
|
static char copyright[] =
|
|
"@(#) Copyright (c) 1988, 1993, 1994\n\
|
|
The Regents of the University of California. All rights reserved.\n";
|
|
#endif /* not lint */
|
|
|
|
#ifndef lint
|
|
static char sccsid[] = "@(#)su.c 8.3 (Berkeley) 4/2/94";
|
|
#endif /* not lint */
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/time.h>
|
|
#include <sys/resource.h>
|
|
|
|
#include <err.h>
|
|
#include <errno.h>
|
|
#include <grp.h>
|
|
#include <paths.h>
|
|
#include <pwd.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <syslog.h>
|
|
#include <unistd.h>
|
|
|
|
#ifdef SKEY
|
|
#include <skey.h>
|
|
#endif
|
|
|
|
#ifdef KERBEROS
|
|
#include <kerberosIV/des.h>
|
|
#include <kerberosIV/krb.h>
|
|
#include <netdb.h>
|
|
|
|
#define ARGSTR "-Kflm"
|
|
|
|
int use_kerberos = 1;
|
|
#else
|
|
#define ARGSTR "-flm"
|
|
#endif
|
|
|
|
char *ontty __P((void));
|
|
int chshell __P((char *));
|
|
|
|
int
|
|
main(argc, argv)
|
|
int argc;
|
|
char **argv;
|
|
{
|
|
extern char **environ;
|
|
struct passwd *pwd;
|
|
#ifdef WHEELSU
|
|
char *targetpass;
|
|
int iswheelsu;
|
|
#endif /* WHEELSU */
|
|
char *p, **g, *user, *shell, *username, *cleanenv[20], *nargv[4], **np;
|
|
struct group *gr;
|
|
uid_t ruid;
|
|
int asme, ch, asthem, fastlogin, prio;
|
|
enum { UNSET, YES, NO } iscsh = UNSET;
|
|
char shellbuf[MAXPATHLEN];
|
|
|
|
np = &nargv[3];
|
|
*np-- = NULL;
|
|
#ifdef WHEELSU
|
|
iswheelsu =
|
|
#endif /* WHEELSU */
|
|
asme = asthem = fastlogin = 0;
|
|
while ((ch = getopt(argc, argv, ARGSTR)) != EOF)
|
|
switch((char)ch) {
|
|
#ifdef KERBEROS
|
|
case 'K':
|
|
use_kerberos = 0;
|
|
break;
|
|
#endif
|
|
case 'f':
|
|
fastlogin = 1;
|
|
break;
|
|
case '-':
|
|
case 'l':
|
|
asme = 0;
|
|
asthem = 1;
|
|
break;
|
|
case 'm':
|
|
asme = 1;
|
|
asthem = 0;
|
|
break;
|
|
case '?':
|
|
default:
|
|
(void)fprintf(stderr, "usage: su [%s] [login]\n",
|
|
ARGSTR);
|
|
exit(1);
|
|
}
|
|
argv += optind;
|
|
|
|
errno = 0;
|
|
prio = getpriority(PRIO_PROCESS, 0);
|
|
if (errno)
|
|
prio = 0;
|
|
(void)setpriority(PRIO_PROCESS, 0, -2);
|
|
openlog("su", LOG_CONS, 0);
|
|
|
|
/* get current login name and shell */
|
|
ruid = getuid();
|
|
username = getlogin();
|
|
if (username == NULL || (pwd = getpwnam(username)) == NULL ||
|
|
pwd->pw_uid != ruid)
|
|
pwd = getpwuid(ruid);
|
|
if (pwd == NULL)
|
|
errx(1, "who are you?");
|
|
username = strdup(pwd->pw_name);
|
|
if (username == NULL)
|
|
err(1, NULL);
|
|
if (asme)
|
|
if (pwd->pw_shell && *pwd->pw_shell)
|
|
shell = strcpy(shellbuf, pwd->pw_shell);
|
|
else {
|
|
shell = _PATH_BSHELL;
|
|
iscsh = NO;
|
|
}
|
|
|
|
/* get target login information, default to root */
|
|
user = *argv ? *argv : "root";
|
|
if ((pwd = getpwnam(user)) == NULL) {
|
|
errx(1, "unknown login: %s", user);
|
|
}
|
|
|
|
#ifdef WHEELSU
|
|
targetpass = strdup(pwd->pw_passwd);
|
|
#endif /* WHEELSU */
|
|
|
|
if (ruid) {
|
|
#ifdef KERBEROS
|
|
if (!use_kerberos || kerberos(username, user, pwd->pw_uid))
|
|
#endif
|
|
{
|
|
/* 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)
|
|
errx(1,
|
|
"you are not in the correct group to su %s.",
|
|
user);
|
|
if (strcmp(username, *g) == 0) {
|
|
#ifdef WHEELSU
|
|
iswheelsu = 1;
|
|
#endif /* WHEELSU */
|
|
break;
|
|
}
|
|
}
|
|
/* if target requires a password, verify it */
|
|
if (*pwd->pw_passwd) {
|
|
#ifdef SKEY
|
|
#ifdef WHEELSU
|
|
if (iswheelsu) {
|
|
pwd = getpwnam(username);
|
|
}
|
|
#endif /* WHEELSU */
|
|
p = skey_getpass("Password:", pwd, 1);
|
|
if (!(!strcmp(pwd->pw_passwd,
|
|
skey_crypt(p, pwd->pw_passwd, pwd, 1))
|
|
#ifdef WHEELSU
|
|
|| (iswheelsu && !strcmp(targetpass,
|
|
crypt(p,
|
|
targetpass)))
|
|
#endif /* WHEELSU */
|
|
)) {
|
|
#else
|
|
p = getpass("Password:");
|
|
if (strcmp(pwd->pw_passwd, crypt(p, pwd->pw_passwd))) {
|
|
#endif
|
|
fprintf(stderr, "Sorry\n");
|
|
syslog(LOG_AUTH|LOG_WARNING,
|
|
"BAD SU %s to %s%s", username,
|
|
user, ontty());
|
|
exit(1);
|
|
}
|
|
#ifdef WHEELSU
|
|
if (iswheelsu) {
|
|
pwd = getpwnam(user);
|
|
}
|
|
#endif /* WHEELSU */
|
|
}
|
|
}
|
|
}
|
|
|
|
if (asme) {
|
|
/* if asme and non-standard target shell, must be root */
|
|
if (!chshell(pwd->pw_shell) && ruid)
|
|
errx(1, "permission denied (shell).");
|
|
} else if (pwd->pw_shell && *pwd->pw_shell) {
|
|
shell = pwd->pw_shell;
|
|
iscsh = UNSET;
|
|
} else {
|
|
shell = _PATH_BSHELL;
|
|
iscsh = NO;
|
|
}
|
|
|
|
/* if we're forking a csh, we want to slightly muck the args */
|
|
if (iscsh == UNSET) {
|
|
if (p = strrchr(shell, '/'))
|
|
++p;
|
|
else
|
|
p = shell;
|
|
if ((iscsh = strcmp(p, "csh") ? NO : YES) == NO)
|
|
iscsh = strcmp(p, "tcsh") ? 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) {
|
|
p = getenv("TERM");
|
|
cleanenv[0] = NULL;
|
|
environ = cleanenv;
|
|
(void)setenv("PATH", _PATH_DEFPATH, 1);
|
|
(void)setenv("TERM", p, 1);
|
|
if (chdir(pwd->pw_dir) < 0)
|
|
errx(1, "no directory");
|
|
}
|
|
if (asthem || pwd->pw_uid)
|
|
(void)setenv("USER", pwd->pw_name, 1);
|
|
(void)setenv("HOME", pwd->pw_dir, 1);
|
|
(void)setenv("SHELL", shell, 1);
|
|
}
|
|
|
|
if (iscsh == YES) {
|
|
if (fastlogin)
|
|
*np-- = "-f";
|
|
if (asme)
|
|
*np-- = "-m";
|
|
}
|
|
|
|
/* csh strips the first character... */
|
|
*np = asthem ? "-su" : iscsh == YES ? "_su" : "su";
|
|
|
|
if (ruid != 0)
|
|
syslog(LOG_NOTICE|LOG_AUTH, "%s to %s%s",
|
|
username, user, ontty());
|
|
|
|
(void)setpriority(PRIO_PROCESS, 0, prio);
|
|
|
|
execv(shell, np);
|
|
err(1, "%s", shell);
|
|
}
|
|
|
|
int
|
|
chshell(sh)
|
|
char *sh;
|
|
{
|
|
char *cp;
|
|
|
|
while ((cp = getusershell()) != NULL)
|
|
if (strcmp(cp, sh) == 0)
|
|
return (1);
|
|
return (0);
|
|
}
|
|
|
|
char *
|
|
ontty()
|
|
{
|
|
char *p;
|
|
static char buf[MAXPATHLEN + 4];
|
|
|
|
buf[0] = 0;
|
|
if (p = ttyname(STDERR_FILENO))
|
|
snprintf(buf, sizeof(buf), " on %s", p);
|
|
return (buf);
|
|
}
|
|
|
|
#ifdef KERBEROS
|
|
kerberos(username, user, uid)
|
|
char *username, *user;
|
|
int uid;
|
|
{
|
|
extern char *krb_err_txt[];
|
|
KTEXT_ST ticket;
|
|
AUTH_DAT authdata;
|
|
struct hostent *hp;
|
|
char *p;
|
|
int kerno;
|
|
u_long faddr;
|
|
char lrealm[REALM_SZ], krbtkfile[MAXPATHLEN];
|
|
char hostname[MAXHOSTNAMELEN], savehost[MAXHOSTNAMELEN];
|
|
char *krb_get_phost();
|
|
|
|
if (krb_get_lrealm(lrealm, 1) != KSUCCESS)
|
|
return (1);
|
|
if (koktologin(username, lrealm, user) && !uid) {
|
|
warnx("kerberos: not in %s's ACL.", user);
|
|
return (1);
|
|
}
|
|
(void)sprintf(krbtkfile, "%s_%s_%d", TKT_ROOT, user, getuid());
|
|
|
|
(void)setenv("KRBTKFILE", krbtkfile, 1);
|
|
(void)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.
|
|
*/
|
|
kerno = krb_get_pw_in_tkt((uid == 0 ? username : user),
|
|
(uid == 0 ? "root" : ""), lrealm,
|
|
"krbtgt", lrealm, DEFAULT_TKT_LIFE, 0);
|
|
|
|
if (kerno != KSUCCESS) {
|
|
if (kerno == KDC_PR_UNKNOWN) {
|
|
warnx("kerberos: principal unknown: %s.%s@%s",
|
|
(uid == 0 ? username : user),
|
|
(uid == 0 ? "root" : ""), lrealm);
|
|
return (1);
|
|
}
|
|
warnx("kerberos: unable to su: %s", krb_err_txt[kerno]);
|
|
syslog(LOG_NOTICE|LOG_AUTH,
|
|
"BAD Kerberos SU: %s to %s%s: %s",
|
|
username, user, ontty(), krb_err_txt[kerno]);
|
|
return (1);
|
|
}
|
|
|
|
if (chown(krbtkfile, uid, -1) < 0) {
|
|
warn("chown");
|
|
(void)unlink(krbtkfile);
|
|
return (1);
|
|
}
|
|
|
|
(void)setpriority(PRIO_PROCESS, 0, -2);
|
|
|
|
if (gethostname(hostname, sizeof(hostname)) == -1) {
|
|
warn("gethostname");
|
|
dest_tkt();
|
|
return (1);
|
|
}
|
|
|
|
(void)strncpy(savehost, krb_get_phost(hostname), sizeof(savehost));
|
|
savehost[sizeof(savehost) - 1] = '\0';
|
|
|
|
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_err_txt[kerno],
|
|
"rcmd", savehost);
|
|
} else if (kerno != KSUCCESS) {
|
|
warnx("Unable to use TGT: %s", krb_err_txt[kerno]);
|
|
syslog(LOG_NOTICE|LOG_AUTH, "failed su: %s to %s%s: %s",
|
|
username, user, ontty(), krb_err_txt[kerno]);
|
|
dest_tkt();
|
|
return (1);
|
|
} else {
|
|
if (!(hp = gethostbyname(hostname))) {
|
|
warnx("can't get addr of %s", hostname);
|
|
dest_tkt();
|
|
return (1);
|
|
}
|
|
memmove((char *)&faddr, (char *)hp->h_addr, sizeof(faddr));
|
|
|
|
if ((kerno = krb_rd_req(&ticket, "rcmd", savehost, faddr,
|
|
&authdata, "")) != KSUCCESS) {
|
|
warnx("kerberos: unable to verify rcmd ticket: %s\n",
|
|
krb_err_txt[kerno]);
|
|
syslog(LOG_NOTICE|LOG_AUTH,
|
|
"failed su: %s to %s%s: %s", username,
|
|
user, ontty(), krb_err_txt[kerno]);
|
|
dest_tkt();
|
|
return (1);
|
|
}
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
koktologin(name, realm, toname)
|
|
char *name, *realm, *toname;
|
|
{
|
|
AUTH_DAT *kdata;
|
|
AUTH_DAT kdata_st;
|
|
|
|
kdata = &kdata_st;
|
|
memset((char *)kdata, 0, sizeof(*kdata));
|
|
(void)strcpy(kdata->pname, name);
|
|
(void)strcpy(kdata->pinst,
|
|
((strcmp(toname, "root") == 0) ? "root" : ""));
|
|
(void)strcpy(kdata->prealm, realm);
|
|
return (kuserok(kdata, toname));
|
|
}
|
|
#endif
|