560 lines
13 KiB
C
560 lines
13 KiB
C
/*
|
|
* Copyright (c) 1999 - 2002 Kungliga Tekniska Högskolan
|
|
* (Royal Institute of Technology, Stockholm, Sweden).
|
|
* 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. Neither the name of KTH 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 KTH AND ITS 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 KTH OR ITS 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 <config.h>
|
|
|
|
RCSID("$Id: su.c,v 1.25 2002/09/10 20:03:47 joda Exp $");
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
#include <syslog.h>
|
|
|
|
#ifdef HAVE_PATHS_H
|
|
#include <paths.h>
|
|
#endif
|
|
|
|
#ifdef HAVE_SHADOW_H
|
|
#include <shadow.h>
|
|
#endif
|
|
|
|
#include <pwd.h>
|
|
|
|
#include "crypto-headers.h"
|
|
#ifdef KRB5
|
|
#include <krb5.h>
|
|
#endif
|
|
#ifdef KRB4
|
|
#include <krb.h>
|
|
#include <kafs.h>
|
|
#endif
|
|
#include <err.h>
|
|
#include <roken.h>
|
|
#include <getarg.h>
|
|
|
|
#ifndef _PATH_DEFPATH
|
|
#define _PATH_DEFPATH "/usr/bin:/bin"
|
|
#endif
|
|
|
|
#ifndef _PATH_BSHELL
|
|
#define _PATH_BSHELL "/bin/sh"
|
|
#endif
|
|
|
|
int kerberos_flag = 1;
|
|
int csh_f_flag;
|
|
int full_login;
|
|
int env_flag;
|
|
char *kerberos_instance = "root";
|
|
int help_flag;
|
|
int version_flag;
|
|
char *cmd;
|
|
char tkfile[256];
|
|
|
|
struct getargs args[] = {
|
|
{ "kerberos", 'K', arg_negative_flag, &kerberos_flag,
|
|
"don't use kerberos" },
|
|
{ NULL, 'f', arg_flag, &csh_f_flag,
|
|
"don't read .cshrc" },
|
|
{ "full", 'l', arg_flag, &full_login,
|
|
"simulate full login" },
|
|
{ NULL, 'm', arg_flag, &env_flag,
|
|
"leave environment unmodified" },
|
|
{ "instance", 'i', arg_string, &kerberos_instance,
|
|
"root instance to use" },
|
|
{ "command", 'c', arg_string, &cmd,
|
|
"command to execute" },
|
|
{ "help", 'h', arg_flag, &help_flag },
|
|
{ "version", 0, arg_flag, &version_flag },
|
|
};
|
|
|
|
|
|
static void
|
|
usage (int ret)
|
|
{
|
|
arg_printusage (args,
|
|
sizeof(args)/sizeof(*args),
|
|
NULL,
|
|
"[login [shell arguments]]");
|
|
exit (ret);
|
|
}
|
|
|
|
static void
|
|
free_info(struct passwd *p)
|
|
{
|
|
free (p->pw_name);
|
|
free (p->pw_passwd);
|
|
free (p->pw_dir);
|
|
free (p->pw_shell);
|
|
free (p);
|
|
}
|
|
|
|
static struct passwd*
|
|
dup_info(const struct passwd *pwd)
|
|
{
|
|
struct passwd *info;
|
|
|
|
info = malloc(sizeof(*info));
|
|
if(info == NULL)
|
|
return NULL;
|
|
info->pw_name = strdup(pwd->pw_name);
|
|
info->pw_passwd = strdup(pwd->pw_passwd);
|
|
info->pw_uid = pwd->pw_uid;
|
|
info->pw_gid = pwd->pw_gid;
|
|
info->pw_dir = strdup(pwd->pw_dir);
|
|
info->pw_shell = strdup(pwd->pw_shell);
|
|
if(info->pw_name == NULL || info->pw_passwd == NULL ||
|
|
info->pw_dir == NULL || info->pw_shell == NULL) {
|
|
free_info (info);
|
|
return NULL;
|
|
}
|
|
return info;
|
|
}
|
|
|
|
#if defined(KRB4) || defined(KRB5)
|
|
static void
|
|
set_tkfile()
|
|
{
|
|
#ifndef TKT_ROOT
|
|
#define TKT_ROOT "/tmp/tkt"
|
|
#endif
|
|
int fd;
|
|
if(*tkfile != '\0')
|
|
return;
|
|
snprintf(tkfile, sizeof(tkfile), "%s_XXXXXX", TKT_ROOT);
|
|
fd = mkstemp(tkfile);
|
|
if(fd >= 0)
|
|
close(fd);
|
|
#ifdef KRB4
|
|
krb_set_tkt_string(tkfile);
|
|
#endif
|
|
}
|
|
#endif
|
|
|
|
#ifdef KRB5
|
|
static krb5_context context;
|
|
static krb5_ccache ccache;
|
|
|
|
static int
|
|
krb5_verify(const struct passwd *login_info,
|
|
const struct passwd *su_info,
|
|
const char *kerberos_instance)
|
|
{
|
|
krb5_error_code ret;
|
|
krb5_principal p;
|
|
char *login_name = NULL;
|
|
|
|
#if defined(HAVE_GETLOGIN) && !defined(POSIX_GETLOGIN)
|
|
login_name = getlogin();
|
|
#endif
|
|
ret = krb5_init_context (&context);
|
|
if (ret) {
|
|
#if 0
|
|
warnx("krb5_init_context failed: %d", ret);
|
|
#endif
|
|
return 1;
|
|
}
|
|
|
|
if (login_name == NULL || strcmp (login_name, "root") == 0)
|
|
login_name = login_info->pw_name;
|
|
if (strcmp (su_info->pw_name, "root") == 0)
|
|
ret = krb5_make_principal(context, &p, NULL,
|
|
login_name,
|
|
kerberos_instance,
|
|
NULL);
|
|
else
|
|
ret = krb5_make_principal(context, &p, NULL,
|
|
su_info->pw_name,
|
|
NULL);
|
|
if(ret)
|
|
return 1;
|
|
|
|
if(su_info->pw_uid != 0 || krb5_kuserok(context, p, su_info->pw_name)) {
|
|
ret = krb5_cc_gen_new(context, &krb5_mcc_ops, &ccache);
|
|
if(ret) {
|
|
#if 1
|
|
krb5_warn(context, ret, "krb5_cc_gen_new");
|
|
#endif
|
|
krb5_free_principal (context, p);
|
|
return 1;
|
|
}
|
|
ret = krb5_verify_user_lrealm(context, p, ccache, NULL, TRUE, NULL);
|
|
krb5_free_principal (context, p);
|
|
if(ret) {
|
|
krb5_cc_destroy(context, ccache);
|
|
switch (ret) {
|
|
case KRB5_LIBOS_PWDINTR :
|
|
break;
|
|
case KRB5KRB_AP_ERR_BAD_INTEGRITY:
|
|
case KRB5KRB_AP_ERR_MODIFIED:
|
|
krb5_warnx(context, "Password incorrect");
|
|
break;
|
|
default :
|
|
krb5_warn(context, ret, "krb5_verify_user");
|
|
break;
|
|
}
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
krb5_free_principal (context, p);
|
|
return 1;
|
|
}
|
|
|
|
static int
|
|
krb5_start_session(void)
|
|
{
|
|
krb5_ccache ccache2;
|
|
char *cc_name;
|
|
int ret;
|
|
|
|
ret = krb5_cc_gen_new(context, &krb5_fcc_ops, &ccache2);
|
|
if (ret) {
|
|
krb5_cc_destroy(context, ccache);
|
|
return 1;
|
|
}
|
|
|
|
ret = krb5_cc_copy_cache(context, ccache, ccache2);
|
|
|
|
asprintf(&cc_name, "%s:%s", krb5_cc_get_type(context, ccache2),
|
|
krb5_cc_get_name(context, ccache2));
|
|
esetenv("KRB5CCNAME", cc_name, 1);
|
|
|
|
/* we want to export this even if we don't directly support KRB4 */
|
|
set_tkfile();
|
|
esetenv("KRBTKFILE", tkfile, 1);
|
|
|
|
#ifdef KRB4
|
|
/* convert creds? */
|
|
if(k_hasafs()) {
|
|
if (k_setpag() == 0)
|
|
krb5_afslog(context, ccache2, NULL, NULL);
|
|
}
|
|
#endif
|
|
|
|
krb5_cc_close(context, ccache2);
|
|
krb5_cc_destroy(context, ccache);
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
#ifdef KRB4
|
|
|
|
static int
|
|
krb_verify(const struct passwd *login_info,
|
|
const struct passwd *su_info,
|
|
const char *kerberos_instance)
|
|
{
|
|
int ret;
|
|
char *login_name = NULL;
|
|
char *name, *instance, realm[REALM_SZ];
|
|
|
|
#if defined(HAVE_GETLOGIN) && !defined(POSIX_GETLOGIN)
|
|
login_name = getlogin();
|
|
#endif
|
|
|
|
ret = krb_get_lrealm(realm, 1);
|
|
|
|
if (login_name == NULL || strcmp (login_name, "root") == 0)
|
|
login_name = login_info->pw_name;
|
|
if (strcmp (su_info->pw_name, "root") == 0) {
|
|
name = login_name;
|
|
instance = (char*)kerberos_instance;
|
|
} else {
|
|
name = su_info->pw_name;
|
|
instance = "";
|
|
}
|
|
|
|
if(su_info->pw_uid != 0 ||
|
|
krb_kuserok(name, instance, realm, su_info->pw_name) == 0) {
|
|
char password[128];
|
|
char *prompt;
|
|
asprintf (&prompt,
|
|
"%s's Password: ",
|
|
krb_unparse_name_long (name, instance, realm));
|
|
if (des_read_pw_string (password, sizeof (password), prompt, 0)) {
|
|
memset (password, 0, sizeof (password));
|
|
free(prompt);
|
|
return (1);
|
|
}
|
|
free(prompt);
|
|
if (strlen(password) == 0)
|
|
return (1); /* Empty passwords are not allowed */
|
|
set_tkfile();
|
|
setuid(geteuid()); /* need to run as root here */
|
|
ret = krb_verify_user(name, instance, realm, password,
|
|
KRB_VERIFY_SECURE, NULL);
|
|
memset(password, 0, sizeof(password));
|
|
|
|
if(ret) {
|
|
warnx("%s", krb_get_err_text(ret));
|
|
return 1;
|
|
}
|
|
chown (tkt_string(), su_info->pw_uid, su_info->pw_gid);
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
|
|
static int
|
|
krb_start_session(void)
|
|
{
|
|
esetenv("KRBTKFILE", tkfile, 1);
|
|
|
|
/* convert creds? */
|
|
if(k_hasafs() && k_setpag() == 0)
|
|
krb_afslog(NULL, NULL);
|
|
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static int
|
|
verify_unix(struct passwd *su)
|
|
{
|
|
char prompt[128];
|
|
char pw_buf[1024];
|
|
char *pw;
|
|
int r;
|
|
if(su->pw_passwd != NULL && *su->pw_passwd != '\0') {
|
|
snprintf(prompt, sizeof(prompt), "%s's password: ", su->pw_name);
|
|
r = des_read_pw_string(pw_buf, sizeof(pw_buf), prompt, 0);
|
|
if(r != 0)
|
|
exit(0);
|
|
pw = crypt(pw_buf, su->pw_passwd);
|
|
memset(pw_buf, 0, sizeof(pw_buf));
|
|
if(strcmp(pw, su->pw_passwd) != 0)
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
main(int argc, char **argv)
|
|
{
|
|
int i, optind = 0;
|
|
char *su_user;
|
|
struct passwd *su_info;
|
|
struct passwd *login_info;
|
|
|
|
struct passwd *pwd;
|
|
|
|
char *shell;
|
|
|
|
int ok = 0;
|
|
int kerberos_error=1;
|
|
|
|
setprogname (argv[0]);
|
|
|
|
if(getarg(args, sizeof(args) / sizeof(args[0]), argc, argv, &optind))
|
|
usage(1);
|
|
|
|
for (i=0; i < optind; i++)
|
|
if (strcmp(argv[i], "-") == 0) {
|
|
full_login = 1;
|
|
break;
|
|
}
|
|
|
|
if(help_flag)
|
|
usage(0);
|
|
if(version_flag) {
|
|
print_version(NULL);
|
|
exit(0);
|
|
}
|
|
if(optind >= argc)
|
|
su_user = "root";
|
|
else
|
|
su_user = argv[optind++];
|
|
|
|
pwd = k_getpwnam(su_user);
|
|
if(pwd == NULL)
|
|
errx (1, "unknown login %s", su_user);
|
|
if (pwd->pw_uid == 0 && strcmp ("root", su_user) != 0) {
|
|
syslog (LOG_ALERT, "NIS attack, user %s has uid 0", su_user);
|
|
errx (1, "unknown login %s", su_user);
|
|
}
|
|
su_info = dup_info(pwd);
|
|
if (su_info == NULL)
|
|
errx (1, "malloc: out of memory");
|
|
|
|
pwd = getpwuid(getuid());
|
|
if(pwd == NULL)
|
|
errx(1, "who are you?");
|
|
login_info = dup_info(pwd);
|
|
if (login_info == NULL)
|
|
errx (1, "malloc: out of memory");
|
|
if(env_flag)
|
|
shell = login_info->pw_shell;
|
|
else
|
|
shell = su_info->pw_shell;
|
|
if(shell == NULL || *shell == '\0')
|
|
shell = _PATH_BSHELL;
|
|
|
|
|
|
#ifdef KRB5
|
|
if(kerberos_flag && ok == 0 &&
|
|
(kerberos_error=krb5_verify(login_info, su_info, kerberos_instance)) == 0)
|
|
ok = 5;
|
|
#endif
|
|
#ifdef KRB4
|
|
if(kerberos_flag && ok == 0 &&
|
|
(kerberos_error = krb_verify(login_info, su_info, kerberos_instance)) == 0)
|
|
ok = 4;
|
|
#endif
|
|
|
|
if(ok == 0 && login_info->pw_uid && verify_unix(su_info) != 0) {
|
|
printf("Sorry!\n");
|
|
exit(1);
|
|
}
|
|
|
|
#ifdef HAVE_GETSPNAM
|
|
{ struct spwd *sp;
|
|
long today;
|
|
|
|
sp = getspnam(su_info->pw_name);
|
|
if (sp != NULL) {
|
|
today = time(0)/(24L * 60 * 60);
|
|
if (sp->sp_expire > 0) {
|
|
if (today >= sp->sp_expire) {
|
|
if (login_info->pw_uid)
|
|
errx(1,"Your account has expired.");
|
|
else
|
|
printf("Your account has expired.");
|
|
}
|
|
else if (sp->sp_expire - today < 14)
|
|
printf("Your account will expire in %d days.\n",
|
|
(int)(sp->sp_expire - today));
|
|
}
|
|
if (sp->sp_max > 0) {
|
|
if (today >= sp->sp_lstchg + sp->sp_max) {
|
|
if (login_info->pw_uid)
|
|
errx(1,"Your password has expired. Choose a new one.");
|
|
else
|
|
printf("Your password has expired. Choose a new one.");
|
|
}
|
|
else if (today >= sp->sp_lstchg + sp->sp_max - sp->sp_warn)
|
|
printf("Your account will expire in %d days.\n",
|
|
(int)(sp->sp_lstchg + sp->sp_max -today));
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
{
|
|
char *tty = ttyname (STDERR_FILENO);
|
|
syslog (LOG_NOTICE | LOG_AUTH, tty ? "%s to %s" : "%s to %s on %s",
|
|
login_info->pw_name, su_info->pw_name, tty);
|
|
}
|
|
|
|
|
|
if(!env_flag) {
|
|
if(full_login) {
|
|
char *t = getenv ("TERM");
|
|
|
|
environ = malloc (10 * sizeof (char *));
|
|
if (environ == NULL)
|
|
err (1, "malloc");
|
|
environ[0] = NULL;
|
|
esetenv ("PATH", _PATH_DEFPATH, 1);
|
|
if (t)
|
|
esetenv ("TERM", t, 1);
|
|
if (chdir (su_info->pw_dir) < 0)
|
|
errx (1, "no directory");
|
|
}
|
|
if (full_login || su_info->pw_uid)
|
|
esetenv ("USER", su_info->pw_name, 1);
|
|
esetenv("HOME", su_info->pw_dir, 1);
|
|
esetenv("SHELL", shell, 1);
|
|
}
|
|
|
|
{
|
|
int i;
|
|
char **args;
|
|
char *p;
|
|
|
|
p = strrchr(shell, '/');
|
|
if(p)
|
|
p++;
|
|
else
|
|
p = shell;
|
|
|
|
if (strcmp(p, "csh") != 0)
|
|
csh_f_flag = 0;
|
|
|
|
args = malloc(((cmd ? 2 : 0) + 1 + argc - optind + 1 + csh_f_flag) * sizeof(*args));
|
|
if (args == NULL)
|
|
err (1, "malloc");
|
|
i = 0;
|
|
if(full_login)
|
|
asprintf(&args[i++], "-%s", p);
|
|
else
|
|
args[i++] = p;
|
|
if (cmd) {
|
|
args[i++] = "-c";
|
|
args[i++] = cmd;
|
|
}
|
|
|
|
if (csh_f_flag)
|
|
args[i++] = "-f";
|
|
|
|
for (argv += optind; *argv; ++argv)
|
|
args[i++] = *argv;
|
|
args[i] = NULL;
|
|
|
|
if(setgid(su_info->pw_gid) < 0)
|
|
err(1, "setgid");
|
|
if (initgroups (su_info->pw_name, su_info->pw_gid) < 0)
|
|
err (1, "initgroups");
|
|
if(setuid(su_info->pw_uid) < 0
|
|
|| (su_info->pw_uid != 0 && setuid(0) == 0))
|
|
err(1, "setuid");
|
|
|
|
#ifdef KRB5
|
|
if (ok == 5)
|
|
krb5_start_session();
|
|
#endif
|
|
#ifdef KRB4
|
|
if (ok == 4)
|
|
krb_start_session();
|
|
#endif
|
|
{
|
|
char **p;
|
|
for(p = args; *p; p++)
|
|
printf("%s ", *p);
|
|
printf("\n");
|
|
}
|
|
execv(shell, args);
|
|
}
|
|
|
|
exit(1);
|
|
}
|