1 /* $NetBSD: pam_chroot.c,v 1.5 2012/01/03 19:02:54 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2003 Networks Associates Technology, Inc.
5 * All rights reserved.
6 *
7 * This software was developed for the FreeBSD Project by ThinkSec AS and
8 * NAI Labs, the Security Research Division of Network Associates, Inc.
9 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
10 * DARPA CHATS research program.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. The name of the author may not be used to endorse or promote
21 * products derived from this software without specific prior written
22 * permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37 #include <sys/cdefs.h>
38 #ifdef __FreeBSD__
39 __FBSDID("$FreeBSD: src/lib/libpam/modules/pam_chroot/pam_chroot.c,v 1.3 2003/04/30 00:40:24 des Exp $");
40 #else
41 __RCSID("$NetBSD: pam_chroot.c,v 1.5 2012/01/03 19:02:54 christos Exp $");
42 #endif
43
44 #include <sys/param.h>
45
46 #include <pwd.h>
47 #include <stdio.h>
48 #include <string.h>
49 #include <errno.h>
50 #include <unistd.h>
51
52 #define PAM_SM_SESSION
53
54 #include <security/pam_appl.h>
55 #include <security/pam_modules.h>
56 #include <security/openpam.h>
57
58 PAM_EXTERN int
pam_sm_open_session(pam_handle_t * pamh,int flags __unused,int argc __unused,const char * argv[]__unused)59 pam_sm_open_session(pam_handle_t *pamh, int flags __unused,
60 int argc __unused, const char *argv[] __unused)
61 {
62 const char *dir, *end, *cwd, *user;
63 struct passwd *pwd, pwres;
64 char buf[PATH_MAX];
65 char pwbuf[1024];
66
67 if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS ||
68 user == NULL ||
69 getpwnam_r(user, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 ||
70 pwd == NULL)
71 return (PAM_SESSION_ERR);
72 if (pwd->pw_uid == 0 && !openpam_get_option(pamh, "also_root"))
73 return (PAM_SUCCESS);
74 if (pwd->pw_dir == NULL)
75 return (PAM_SESSION_ERR);
76 if ((end = strstr(pwd->pw_dir, "/./")) != NULL) {
77 if (snprintf(buf, sizeof(buf), "%.*s",
78 (int)(end - pwd->pw_dir), pwd->pw_dir) > (int)sizeof(buf)) {
79 openpam_log(PAM_LOG_ERROR,
80 "%s's home directory is too long", user);
81 return (PAM_SESSION_ERR);
82 }
83 dir = buf;
84 cwd = end + 2;
85 } else if ((dir = openpam_get_option(pamh, "dir")) != NULL) {
86 if ((cwd = openpam_get_option(pamh, "cwd")) == NULL)
87 cwd = "/";
88 } else {
89 if (openpam_get_option(pamh, "always")) {
90 openpam_log(PAM_LOG_ERROR,
91 "%s has no chroot directory", user);
92 return (PAM_SESSION_ERR);
93 }
94 return (PAM_SUCCESS);
95 }
96
97 openpam_log(PAM_LOG_DEBUG, "chrooting %s to %s", dir, user);
98
99 if (chroot(dir) == -1) {
100 openpam_log(PAM_LOG_ERROR, "chroot(): %s", strerror(errno));
101 return (PAM_SESSION_ERR);
102 }
103 if (chdir(cwd) == -1) {
104 openpam_log(PAM_LOG_ERROR, "chdir(): %s", strerror(errno));
105 return (PAM_SESSION_ERR);
106 }
107 pam_setenv(pamh, "HOME", cwd, 1);
108 return (PAM_SUCCESS);
109 }
110
111 PAM_EXTERN int
pam_sm_close_session(pam_handle_t * pamh __unused,int flags __unused,int argc __unused,const char * argv[]__unused)112 pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused,
113 int argc __unused, const char *argv[] __unused)
114 {
115
116 return (PAM_SUCCESS);
117 }
118
119 PAM_MODULE_ENTRY("pam_chroot");
120