su
git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@5989 ec53bebd-3082-4978-b11e-865c3cabbd6b
This commit is contained in:
Johan Danielsson
293
appl/su/su.c
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293
appl/su/su.c
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/*
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* Copyright (c) 1999 Kungliga Tekniska H<>gskolan
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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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#include <paths.h>
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#include <pwd.h>
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#include <krb5.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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#ifndef _PATH_DEFPATH
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#define _PATH_DEFPATH "/usr/bin:/bin"
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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;
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int help_flag;
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int version_flag;
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struct getargs args[] = {
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{ "kerberos", 'K', arg_negative_flag, &kerberos_flag, "don't use kerberos" },
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{ NULL, 'f', arg_flag, &csh_f_flag, "don't read .cshrc" },
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{ "full", 'l', arg_flag, &full_login, "simulate full login" },
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{ NULL, 'm', arg_flag, &env_flag, "leave environment" },
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{ "instance",'i', arg_string, &kerberos_instance, "root instance to use" },
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{ "help", 'h', arg_flag, &help_flag },
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{ "version", 0, arg_flag, &version_flag },
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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 struct passwd*
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make_info(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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return NULL;
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return info;
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}
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static int
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verify_krb5(struct passwd *login_info, struct passwd *su_info)
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{
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#ifdef KRB5
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krb5_context context;
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krb5_error_code ret;
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krb5_principal p;
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krb5_ccache ccache;
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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: %u", ret);
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#endif
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return 1;
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}
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ret = krb5_make_principal(context, &p, NULL,
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login_info->pw_name, "root", NULL);
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if(ret)
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return 1;
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if(su_info->pw_uid != 0 || krb5_kuserok(context, p, su_info->pw_name)) {
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ret = krb5_cc_gen_new(context, &krb5_fcc_ops, &ccache);
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if(ret) {
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#if 1
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krb5_warn(context, ret, "krb5_cc_gen_new");
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#endif
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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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if(ret) {
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krb5_cc_destroy(context, ccache);
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#if 1
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krb5_warn(context, ret, "krb5_verify_user");
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#endif
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return 1;
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}
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{
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char *s;
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asprintf(&s, "%s:%s", krb5_cc_get_type(context, ccache),
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krb5_cc_get_name(context, ccache));
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setenv("KRB5CCNAME", s, 1);
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}
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return 0;
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}
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#endif
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return 1;
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}
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static int
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verify_unix(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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sprintf(prompt, "%s's password: ", su->pw_name);
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r = des_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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return 1;
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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 optind = 0;
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char *su_user;
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struct passwd *su_info;
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char *login_user;
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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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set_progname (argv[0]);
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if(getarg(args, sizeof(args) / sizeof(args[0]), argc, argv, &optind))
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usage(1);
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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(optind >= argc)
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su_user = "root";
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else
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su_user = argv[optind++];
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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 = make_info(pwd);
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login_user = getlogin();
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if(login_user == NULL || (pwd = getpwnam(login_user)) == NULL)
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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 = make_info(pwd);
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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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if(ok == 0 && verify_krb5(login_info, su_info) == 0)
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ok++;
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if(ok == 0 && verify_unix(su_info) != 0) {
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printf("Sorry!\n");
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exit(1);
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}
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{
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char *tty = ttyname (STDERR_FILENO);
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syslog (LOG_NOTICE | LOG_AUTH, tty ? "%s to %s" : "%s to %s on %s",
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login_info->pw_name, su_info->pw_name, tty);
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}
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if(!env_flag) {
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if(full_login) {
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char *k = getenv ("KRBTKFILE");
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char *t = getenv ("TERM");
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environ = malloc (10 * 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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setenv ("PATH", _PATH_DEFPATH, 1);
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if (t)
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setenv ("TERM", t, 1);
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if (k)
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setenv ("KRBTKFILE", k, 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 (full_login || su_info->pw_uid)
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setenv ("USER", su_info->pw_name, 1);
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setenv("HOME", su_info->pw_dir, 1);
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setenv("SHELL", shell, 1);
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}
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{
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int i;
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char **args;
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char *p;
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args = malloc((1 + argc - optind + 1) * sizeof(*args));
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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(full_login)
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asprintf(&args[0], "-%s", p);
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else
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args[0] = p;
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for(i = 1; i < argc - optind + 1; i++)
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args[i] = argv[optind + i - 1];
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args[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)
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err (1, "initgroups");
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if(setuid(su_info->pw_uid) < 0)
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err(1, "setuid");
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execv(shell, args);
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}
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exit(1);
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}
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