source: openpam/trunk/bin/su/su.c @ 213

Last change on this file since 213 was 157, checked in by Dag-Erling Smørgrav, 19 years ago

DBA update and minor whitespace fixes.

File size: 4.9 KB
Line 
1/*-
2 * Copyright (c) 2002 Networks Associates Technology, Inc.
3 * All rights reserved.
4 *
5 * This software was developed for the FreeBSD Project by ThinkSec AS and
6 * Network Associates Laboratories, the Security Research Division of
7 * Network Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
8 * ("CBOSS"), as part of the DARPA CHATS research program.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. The name of the author may not be used to endorse or promote
19 *    products derived from this software without specific prior written
20 *    permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * $P4: //depot/projects/openpam/bin/su/su.c#8 $
35 */
36
37#include <sys/param.h>
38#include <sys/wait.h>
39
40#include <err.h>
41#include <pwd.h>
42#include <stdio.h>
43#include <stdlib.h>
44#include <string.h>
45#include <syslog.h>
46#include <unistd.h>
47
48#include <security/pam_appl.h>
49#include <security/openpam.h>   /* for openpam_ttyconv() */
50
51extern char **environ;
52
53static pam_handle_t *pamh;
54static struct pam_conv pamc;
55
56static void
57usage(void)
58{
59
60        fprintf(stderr, "Usage: su [login [args]]\n");
61        exit(1);
62}
63
64int
65main(int argc, char *argv[])
66{
67        char hostname[MAXHOSTNAMELEN];
68        const char *user, *tty;
69        char **args, **pam_envlist, **pam_env;
70        struct passwd *pwd;
71        int o, pam_err, status;
72        pid_t pid;
73
74        while ((o = getopt(argc, argv, "h")) != -1)
75                switch (o) {
76                case 'h':
77                default:
78                        usage();
79                }
80
81        argc -= optind;
82        argv += optind;
83
84        /* initialize PAM */
85        pamc.conv = &openpam_ttyconv;
86        pam_start("su", argc ? *argv : "root", &pamc, &pamh);
87
88        /* set some items */
89        gethostname(hostname, sizeof(hostname));
90        if ((pam_err = pam_set_item(pamh, PAM_RHOST, hostname)) != PAM_SUCCESS)
91                goto pamerr;
92        user = getlogin();
93        if ((pam_err = pam_set_item(pamh, PAM_RUSER, user)) != PAM_SUCCESS)
94                goto pamerr;
95        tty = ttyname(STDERR_FILENO);
96        if ((pam_err = pam_set_item(pamh, PAM_TTY, tty)) != PAM_SUCCESS)
97                goto pamerr;
98
99        /* authenticate the applicant */
100        if ((pam_err = pam_authenticate(pamh, 0)) != PAM_SUCCESS)
101                goto pamerr;
102        if ((pam_err = pam_acct_mgmt(pamh, 0)) == PAM_NEW_AUTHTOK_REQD)
103                pam_err = pam_chauthtok(pamh, PAM_CHANGE_EXPIRED_AUTHTOK);
104        if (pam_err != PAM_SUCCESS)
105                goto pamerr;
106
107        /* establish the requested credentials */
108        if ((pam_err = pam_setcred(pamh, PAM_ESTABLISH_CRED)) != PAM_SUCCESS)
109                goto pamerr;
110
111        /* authentication succeeded; open a session */
112        if ((pam_err = pam_open_session(pamh, 0)) != PAM_SUCCESS)
113                goto pamerr;
114
115        /* get mapped user name; PAM may have changed it */
116        pam_err = pam_get_item(pamh, PAM_USER, (const void **)&user);
117        if (pam_err != PAM_SUCCESS || (pwd = getpwnam(user)) == NULL)
118                goto pamerr;
119
120        /* set uid and groups */
121        if (initgroups(pwd->pw_name, pwd->pw_gid) == -1) {
122                warn("initgroups()");
123                goto err;
124        }
125        if (setgid(pwd->pw_gid) == -1) {
126                warn("setgid()");
127                goto err;
128        }
129        if (setuid(pwd->pw_uid) == -1) {
130                warn("setuid()");
131                goto err;
132        }
133
134        /* export PAM environment */
135        if ((pam_envlist = pam_getenvlist(pamh)) != NULL) {
136                for (pam_env = pam_envlist; *pam_env != NULL; ++pam_env) {
137                        putenv(*pam_env);
138                        free(*pam_env);
139                }
140                free(pam_envlist);
141        }
142
143        /* build argument list */
144        if ((args = calloc(argc + 2, sizeof *args)) == NULL) {
145                warn("calloc()");
146                goto err;
147        }
148        *args = pwd->pw_shell;
149        memcpy(args + 1, argv, argc * sizeof *args);
150
151        /* fork and exec */
152        switch ((pid = fork())) {
153        case -1:
154                warn("fork()");
155                goto err;
156        case 0:
157                /* child: start a shell */
158                execve(*args, args, environ);
159                warn("execve()");
160                _exit(1);
161        default:
162                /* parent: wait for child to exit */
163                waitpid(pid, &status, 0);
164
165                /* close the session and release PAM resources */
166                pam_err = pam_close_session(pamh, 0);
167                pam_end(pamh, pam_err);
168
169                exit(WEXITSTATUS(status));
170        }
171
172pamerr:
173        pam_end(pamh, pam_err);
174        fprintf(stderr, "Sorry\n");
175        exit(1);
176err:
177        pam_end(pamh, pam_err);
178        exit(1);
179}
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