1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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 __FBSDID("$FreeBSD$"); 39 40 #include <sys/param.h> 41 42 #include <pwd.h> 43 #include <stdio.h> 44 #include <string.h> 45 #include <unistd.h> 46 47 #define PAM_SM_SESSION 48 49 #include <security/pam_appl.h> 50 #include <security/pam_modules.h> 51 #include <security/openpam.h> 52 53 PAM_EXTERN int 54 pam_sm_open_session(pam_handle_t *pamh, int flags __unused, 55 int argc __unused, const char *argv[] __unused) 56 { 57 const char *dir, *end, *cwd, *user; 58 struct passwd *pwd; 59 char buf[PATH_MAX]; 60 61 if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS || 62 user == NULL || (pwd = getpwnam(user)) == NULL) 63 return (PAM_SESSION_ERR); 64 if (pwd->pw_uid == 0 && !openpam_get_option(pamh, "also_root")) 65 return (PAM_SUCCESS); 66 if (pwd->pw_dir == NULL) 67 return (PAM_SESSION_ERR); 68 if ((end = strstr(pwd->pw_dir, "/./")) != NULL) { 69 if (snprintf(buf, sizeof(buf), "%.*s", 70 (int)(end - pwd->pw_dir), pwd->pw_dir) > (int)sizeof(buf)) { 71 openpam_log(PAM_LOG_ERROR, 72 "%s's home directory is too long", user); 73 return (PAM_SESSION_ERR); 74 } 75 dir = buf; 76 cwd = end + 2; 77 } else if ((dir = openpam_get_option(pamh, "dir")) != NULL) { 78 if ((cwd = openpam_get_option(pamh, "cwd")) == NULL) 79 cwd = "/"; 80 } else { 81 if (openpam_get_option(pamh, "always")) { 82 openpam_log(PAM_LOG_ERROR, 83 "%s has no chroot directory", user); 84 return (PAM_SESSION_ERR); 85 } 86 return (PAM_SUCCESS); 87 } 88 89 openpam_log(PAM_LOG_DEBUG, "chrooting %s to %s", dir, user); 90 91 if (chroot(dir) == -1) { 92 openpam_log(PAM_LOG_ERROR, "chroot(): %m"); 93 return (PAM_SESSION_ERR); 94 } 95 if (chdir(cwd) == -1) { 96 openpam_log(PAM_LOG_ERROR, "chdir(): %m"); 97 return (PAM_SESSION_ERR); 98 } 99 pam_setenv(pamh, "HOME", cwd, 1); 100 return (PAM_SUCCESS); 101 } 102 103 PAM_EXTERN int 104 pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused, 105 int argc __unused, const char *argv[] __unused) 106 { 107 108 return (PAM_SUCCESS); 109 } 110 111 PAM_MODULE_ENTRY("pam_chroot"); 112