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/param.h> 38 39 #include <pwd.h> 40 #include <stdio.h> 41 #include <string.h> 42 #include <unistd.h> 43 44 #define PAM_SM_SESSION 45 46 #include <security/pam_appl.h> 47 #include <security/pam_modules.h> 48 #include <security/openpam.h> 49 50 PAM_EXTERN int 51 pam_sm_open_session(pam_handle_t *pamh, int flags __unused, 52 int argc __unused, const char *argv[] __unused) 53 { 54 const char *dir, *end, *cwd, *user; 55 struct passwd *pwd; 56 char buf[PATH_MAX]; 57 58 if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS || 59 user == NULL || (pwd = getpwnam(user)) == NULL) 60 return (PAM_SESSION_ERR); 61 if (pwd->pw_uid == 0 && !openpam_get_option(pamh, "also_root")) 62 return (PAM_SUCCESS); 63 if (pwd->pw_dir == NULL) 64 return (PAM_SESSION_ERR); 65 if ((end = strstr(pwd->pw_dir, "/./")) != NULL) { 66 if (snprintf(buf, sizeof(buf), "%.*s", 67 (int)(end - pwd->pw_dir), pwd->pw_dir) > (int)sizeof(buf)) { 68 openpam_log(PAM_LOG_ERROR, 69 "%s's home directory is too long", user); 70 return (PAM_SESSION_ERR); 71 } 72 dir = buf; 73 cwd = end + 2; 74 } else if ((dir = openpam_get_option(pamh, "dir")) != NULL) { 75 if ((cwd = openpam_get_option(pamh, "cwd")) == NULL) 76 cwd = "/"; 77 } else { 78 if (openpam_get_option(pamh, "always")) { 79 openpam_log(PAM_LOG_ERROR, 80 "%s has no chroot directory", user); 81 return (PAM_SESSION_ERR); 82 } 83 return (PAM_SUCCESS); 84 } 85 86 openpam_log(PAM_LOG_DEBUG, "chrooting %s to %s", dir, user); 87 88 if (chroot(dir) == -1) { 89 openpam_log(PAM_LOG_ERROR, "chroot(): %m"); 90 return (PAM_SESSION_ERR); 91 } 92 if (chdir(cwd) == -1) { 93 openpam_log(PAM_LOG_ERROR, "chdir(): %m"); 94 return (PAM_SESSION_ERR); 95 } 96 pam_setenv(pamh, "HOME", cwd, 1); 97 return (PAM_SUCCESS); 98 } 99 100 PAM_EXTERN int 101 pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused, 102 int argc __unused, const char *argv[] __unused) 103 { 104 105 return (PAM_SUCCESS); 106 } 107 108 PAM_MODULE_ENTRY("pam_chroot"); 109