531 lines
13 KiB
C
531 lines
13 KiB
C
/*
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* Copyright (c) 1999 - 2008 Kungliga Tekniska Högskolan
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* (Royal Institute of Technology, Stockholm, Sweden).
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* 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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*
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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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*
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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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*
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* 3. Neither the name of KTH nor the names of its contributors may be
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* used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY KTH AND ITS CONTRIBUTORS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KTH OR ITS CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
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#include <config.h>
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RCSID("$Id$");
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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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#ifdef HAVE_PATHS_H
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#include <paths.h>
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#endif
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#ifdef HAVE_SHADOW_H
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#include <shadow.h>
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#endif
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#include <pwd.h>
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#ifdef HAVE_CRYPT_H
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#include <crypt.h>
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#endif
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#include "crypto-headers.h"
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#ifdef KRB5
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#include <krb5.h>
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#endif
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#include <kafs.h>
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#include <err.h>
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#include <roken.h>
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#include <getarg.h>
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#include "supaths.h"
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#if !HAVE_DECL_ENVIRON
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extern char **environ;
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#endif
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int kerberos_flag = 1;
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int csh_f_flag;
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int full_login;
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int env_flag;
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char *kerberos_instance = "root";
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int help_flag;
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int version_flag;
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char *cmd;
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char tkfile[256];
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struct getargs args[] = {
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{ "kerberos", 'K', arg_negative_flag, &kerberos_flag,
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"don't use kerberos", NULL },
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{ NULL, 'f', arg_flag, &csh_f_flag,
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"don't read .cshrc", NULL },
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{ "full", 'l', arg_flag, &full_login,
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"simulate full login", NULL },
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{ NULL, 'm', arg_flag, &env_flag,
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"leave environment unmodified", NULL },
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{ "instance", 'i', arg_string, &kerberos_instance,
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"root instance to use", NULL },
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{ "command", 'c', arg_string, &cmd,
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"command to execute", NULL },
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{ "help", 'h', arg_flag, &help_flag, NULL, NULL },
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{ "version", 0, arg_flag, &version_flag, NULL, NULL },
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};
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static void
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usage (int ret)
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{
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arg_printusage (args,
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sizeof(args)/sizeof(*args),
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NULL,
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"[login [shell arguments]]");
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exit (ret);
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}
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static void
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free_info(struct passwd *p)
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{
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free (p->pw_name);
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free (p->pw_passwd);
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free (p->pw_dir);
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free (p->pw_shell);
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free (p);
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}
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static struct passwd*
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dup_info(const struct passwd *pwd)
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{
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struct passwd *info;
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info = malloc(sizeof(*info));
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if(info == NULL)
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return NULL;
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info->pw_name = strdup(pwd->pw_name);
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info->pw_passwd = strdup(pwd->pw_passwd);
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info->pw_uid = pwd->pw_uid;
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info->pw_gid = pwd->pw_gid;
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info->pw_dir = strdup(pwd->pw_dir);
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info->pw_shell = strdup(pwd->pw_shell);
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if(info->pw_name == NULL || info->pw_passwd == NULL ||
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info->pw_dir == NULL || info->pw_shell == NULL) {
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free_info (info);
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return NULL;
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}
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return info;
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}
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#ifdef KRB5
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static krb5_context context;
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static krb5_ccache ccache;
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static int
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krb5_verify(const struct passwd *login_info,
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const struct passwd *su_info,
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const char *instance)
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{
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krb5_error_code ret;
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krb5_principal p;
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krb5_realm *realms, *r;
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char *login_name = NULL;
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int user_ok = 0;
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#if defined(HAVE_GETLOGIN) && !defined(POSIX_GETLOGIN)
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login_name = getlogin();
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#endif
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ret = krb5_init_context (&context);
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if (ret) {
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#if 0
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warnx("krb5_init_context failed: %d", ret);
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#endif
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return 1;
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}
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ret = krb5_get_default_realms(context, &realms);
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if (ret)
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return 1;
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/* Check all local realms */
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for (r = realms; *r != NULL && !user_ok; r++) {
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if (login_name == NULL || strcmp (login_name, "root") == 0)
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login_name = login_info->pw_name;
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if (strcmp (su_info->pw_name, "root") == 0)
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ret = krb5_make_principal(context, &p, *r,
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login_name,
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instance,
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NULL);
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else
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ret = krb5_make_principal(context, &p, *r,
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su_info->pw_name,
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NULL);
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if (ret) {
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krb5_free_host_realm(context, realms);
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return 1;
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}
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/* if we are su-ing too root, check with krb5_kuserok */
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if (su_info->pw_uid == 0 && !krb5_kuserok(context, p, su_info->pw_name))
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continue;
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ret = krb5_cc_new_unique(context, krb5_cc_type_memory, NULL, &ccache);
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if(ret) {
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krb5_free_host_realm(context, realms);
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krb5_free_principal (context, p);
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return 1;
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}
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ret = krb5_verify_user(context, p, ccache, NULL, TRUE, NULL);
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krb5_free_principal (context, p);
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switch (ret) {
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case 0:
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user_ok = 1;
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break;
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case KRB5_LIBOS_PWDINTR :
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krb5_cc_destroy(context, ccache);
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break;
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case KRB5KRB_AP_ERR_BAD_INTEGRITY:
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case KRB5KRB_AP_ERR_MODIFIED:
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krb5_cc_destroy(context, ccache);
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krb5_warnx(context, "Password incorrect");
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break;
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default :
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krb5_cc_destroy(context, ccache);
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krb5_warn(context, ret, "krb5_verify_user");
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break;
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}
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}
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krb5_free_host_realm(context, realms);
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if (!user_ok)
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return 1;
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return 0;
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}
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static int
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krb5_start_session(void)
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{
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krb5_ccache ccache2;
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char *cc_name;
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int ret;
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ret = krb5_cc_new_unique(context, krb5_cc_type_file, NULL, &ccache2);
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if (ret) {
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krb5_cc_destroy(context, ccache);
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return 1;
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}
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ret = krb5_cc_copy_cache(context, ccache, ccache2);
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if (ret) {
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krb5_cc_destroy(context, ccache);
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krb5_cc_destroy(context, ccache2);
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return 1;
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}
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ret = asprintf(&cc_name, "%s:%s", krb5_cc_get_type(context, ccache2),
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krb5_cc_get_name(context, ccache2));
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if (ret == -1) {
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krb5_cc_destroy(context, ccache);
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krb5_cc_destroy(context, ccache2);
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errx(1, "malloc - out of memory");
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}
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esetenv("KRB5CCNAME", cc_name, 1);
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/* convert creds? */
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if(k_hasafs()) {
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if (k_setpag() == 0)
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krb5_afslog(context, ccache2, NULL, NULL);
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}
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krb5_cc_close(context, ccache2);
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krb5_cc_destroy(context, ccache);
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return 0;
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}
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#endif
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#define GROUP_MEMBER 0
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#define GROUP_MISSING 1
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#define GROUP_EMPTY 2
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#define GROUP_NOT_MEMBER 3
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static int
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group_member_p(const char *group, const char *user)
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{
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struct group *g;
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int i;
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g = getgrnam(group);
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if(g == NULL)
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return GROUP_MISSING;
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if(g->gr_mem[0] == NULL)
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return GROUP_EMPTY;
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for(i = 0; g->gr_mem[i] != NULL; i++)
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if(strcmp(user, g->gr_mem[i]) == 0)
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return GROUP_MEMBER;
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return GROUP_NOT_MEMBER;
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}
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static int
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verify_unix(struct passwd *login, struct passwd *su)
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{
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char prompt[128];
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char pw_buf[1024];
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char *pw;
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int r;
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if(su->pw_passwd != NULL && *su->pw_passwd != '\0') {
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snprintf(prompt, sizeof(prompt), "%s's password: ", su->pw_name);
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r = UI_UTIL_read_pw_string(pw_buf, sizeof(pw_buf), prompt, 0);
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if(r != 0)
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exit(0);
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pw = crypt(pw_buf, su->pw_passwd);
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memset(pw_buf, 0, sizeof(pw_buf));
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if(strcmp(pw, su->pw_passwd) != 0) {
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syslog (LOG_ERR | LOG_AUTH, "%s to %s: incorrect password",
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login->pw_name, su->pw_name);
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return 1;
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}
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}
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/* if su:ing to root, check membership of group wheel or root; if
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that group doesn't exist, or is empty, allow anyone to su
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root */
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if(su->pw_uid == 0) {
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#ifndef ROOT_GROUP
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#define ROOT_GROUP "wheel"
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#endif
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int gs = group_member_p(ROOT_GROUP, login->pw_name);
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if(gs == GROUP_NOT_MEMBER) {
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syslog (LOG_ERR | LOG_AUTH, "%s to %s: not in group %s",
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login->pw_name, su->pw_name, ROOT_GROUP);
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return 1;
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}
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return 0;
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}
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return 0;
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}
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int
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main(int argc, char **argv)
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{
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int i, optidx = 0;
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char *su_user;
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struct passwd *su_info;
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struct passwd *login_info;
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struct passwd *pwd;
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char *shell;
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int ok = 0;
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setprogname (argv[0]);
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if(getarg(args, sizeof(args) / sizeof(args[0]), argc, argv, &optidx))
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usage(1);
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for (i=0; i < optidx; i++)
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if (strcmp(argv[i], "-") == 0) {
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full_login = 1;
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break;
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}
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if(help_flag)
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usage(0);
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if(version_flag) {
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print_version(NULL);
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exit(0);
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}
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if(optidx >= argc)
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su_user = "root";
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else
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su_user = argv[optidx++];
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if (!issuid() && getuid() != 0)
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warnx("Not setuid and you are not root, expect this to fail");
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pwd = k_getpwnam(su_user);
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if(pwd == NULL)
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errx (1, "unknown login %s", su_user);
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if (pwd->pw_uid == 0 && strcmp ("root", su_user) != 0) {
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syslog (LOG_ALERT, "NIS attack, user %s has uid 0", su_user);
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errx (1, "unknown login %s", su_user);
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}
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su_info = dup_info(pwd);
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if (su_info == NULL)
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errx (1, "malloc: out of memory");
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pwd = getpwuid(getuid());
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if(pwd == NULL)
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errx(1, "who are you?");
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login_info = dup_info(pwd);
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if (login_info == NULL)
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errx (1, "malloc: out of memory");
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if(env_flag)
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shell = login_info->pw_shell;
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else
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shell = su_info->pw_shell;
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if(shell == NULL || *shell == '\0')
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shell = _PATH_BSHELL;
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#ifdef KRB5
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if(kerberos_flag && ok == 0 &&
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krb5_verify(login_info, su_info, kerberos_instance) == 0)
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ok = 5;
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#endif
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if(ok == 0 && login_info->pw_uid && verify_unix(login_info, su_info) != 0) {
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printf("Sorry!\n");
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exit(1);
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}
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#ifdef HAVE_GETSPNAM
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{ struct spwd *sp;
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long today;
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sp = getspnam(su_info->pw_name);
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if (sp != NULL) {
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today = time(0)/(24L * 60 * 60);
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if (sp->sp_expire > 0) {
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if (today >= sp->sp_expire) {
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if (login_info->pw_uid)
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errx(1,"Your account has expired.");
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else
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printf("Your account has expired.");
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}
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else if (sp->sp_expire - today < 14)
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printf("Your account will expire in %d days.\n",
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(int)(sp->sp_expire - today));
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}
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if (sp->sp_max > 0) {
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if (today >= sp->sp_lstchg + sp->sp_max) {
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if (login_info->pw_uid)
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errx(1,"Your password has expired. Choose a new one.");
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else
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printf("Your password has expired. Choose a new one.");
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}
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else if (today >= sp->sp_lstchg + sp->sp_max - sp->sp_warn)
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printf("Your account will expire in %d days.\n",
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(int)(sp->sp_lstchg + sp->sp_max -today));
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}
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}
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}
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#endif
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{
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char *tty = ttyname (STDERR_FILENO);
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if (tty)
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syslog (LOG_NOTICE | LOG_AUTH, "%s to %s on %s",
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login_info->pw_name, su_info->pw_name, tty);
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else
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syslog (LOG_NOTICE | LOG_AUTH, "%s to %s",
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login_info->pw_name, su_info->pw_name);
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}
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if(!env_flag) {
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if(full_login) {
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char *t = getenv ("TERM");
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char **newenv = NULL;
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int j;
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i = read_environment(_PATH_ETC_ENVIRONMENT, &newenv);
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environ = malloc ((10 + i) * sizeof (char *));
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if (environ == NULL)
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err (1, "malloc");
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environ[0] = NULL;
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for (j = 0; j < i; j++) {
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char *p = strchr(newenv[j], '=');
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if (p == NULL)
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errx(1, "enviroment '%s' missing '='", newenv[j]);
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*p++ = 0;
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esetenv (newenv[j], p, 1);
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}
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free(newenv);
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esetenv ("PATH", _PATH_DEFPATH, 1);
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if (t)
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esetenv ("TERM", t, 1);
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if (chdir (su_info->pw_dir) < 0)
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errx (1, "no directory");
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}
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if (full_login || su_info->pw_uid)
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esetenv ("USER", su_info->pw_name, 1);
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esetenv("HOME", su_info->pw_dir, 1);
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esetenv("SHELL", shell, 1);
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}
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{
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char **new_argv;
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char *p;
|
|
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p = strrchr(shell, '/');
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if(p)
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p++;
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else
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p = shell;
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if (strcmp(p, "csh") != 0)
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csh_f_flag = 0;
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new_argv = malloc(((cmd ? 2 : 0) + 1 + argc - optidx + 1 + csh_f_flag)
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* sizeof(*new_argv));
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if (new_argv == NULL)
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err (1, "malloc");
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i = 0;
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if(full_login) {
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if (asprintf(&new_argv[i++], "-%s", p) == -1)
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errx (1, "malloc");
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} else
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new_argv[i++] = p;
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if (cmd) {
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new_argv[i++] = "-c";
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new_argv[i++] = cmd;
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}
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|
|
if (csh_f_flag)
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new_argv[i++] = "-f";
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for (argv += optidx; *argv; ++argv)
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new_argv[i++] = *argv;
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new_argv[i] = NULL;
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if(setgid(su_info->pw_gid) < 0)
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err(1, "setgid");
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if (initgroups (su_info->pw_name, su_info->pw_gid) < 0)
|
|
err (1, "initgroups");
|
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if(setuid(su_info->pw_uid) < 0
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|| (su_info->pw_uid != 0 && setuid(0) == 0))
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|
err(1, "setuid");
|
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|
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#ifdef KRB5
|
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if (ok == 5)
|
|
krb5_start_session();
|
|
#endif
|
|
execve(shell, new_argv, environ);
|
|
}
|
|
|
|
exit(1);
|
|
}
|