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 * $FreeBSD: head/lib/libpam/modules/pam_chroot/pam_chroot.c 326219 2017-11-26 02:00:33Z pfg $ 37 */ 38 39 #include <sys/param.h> 40 41 #include <pwd.h> 42 #include <stdio.h> 43 #include <string.h> 44 #include <unistd.h> 45 46 #define PAM_SM_SESSION 47 48 #include <security/pam_appl.h> 49 #include <security/pam_modules.h> 50 #include <security/openpam.h> 51 52 PAM_EXTERN int 53 pam_sm_open_session(pam_handle_t *pamh, int flags __unused, 54 int argc __unused, const char *argv[] __unused) 55 { 56 const char *dir, *end, *cwd, *user; 57 struct passwd *pwd; 58 char buf[PATH_MAX]; 59 60 if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS || 61 user == NULL || (pwd = getpwnam(user)) == NULL) 62 return (PAM_SESSION_ERR); 63 if (pwd->pw_uid == 0 && !openpam_get_option(pamh, "also_root")) 64 return (PAM_SUCCESS); 65 if (pwd->pw_dir == NULL) 66 return (PAM_SESSION_ERR); 67 if ((end = strstr(pwd->pw_dir, "/./")) != NULL) { 68 if (snprintf(buf, sizeof(buf), "%.*s", 69 (int)(end - pwd->pw_dir), pwd->pw_dir) > (int)sizeof(buf)) { 70 openpam_log(PAM_LOG_ERROR, 71 "%s's home directory is too long", user); 72 return (PAM_SESSION_ERR); 73 } 74 dir = buf; 75 cwd = end + 2; 76 } else if ((dir = openpam_get_option(pamh, "dir")) != NULL) { 77 if ((cwd = openpam_get_option(pamh, "cwd")) == NULL) 78 cwd = "/"; 79 } else { 80 if (openpam_get_option(pamh, "always")) { 81 openpam_log(PAM_LOG_ERROR, 82 "%s has no chroot directory", user); 83 return (PAM_SESSION_ERR); 84 } 85 return (PAM_SUCCESS); 86 } 87 88 openpam_log(PAM_LOG_DEBUG, "chrooting %s to %s", dir, user); 89 90 if (chroot(dir) == -1) { 91 openpam_log(PAM_LOG_ERROR, "chroot(): %m"); 92 return (PAM_SESSION_ERR); 93 } 94 if (chdir(cwd) == -1) { 95 openpam_log(PAM_LOG_ERROR, "chdir(): %m"); 96 return (PAM_SESSION_ERR); 97 } 98 pam_setenv(pamh, "HOME", cwd, 1); 99 return (PAM_SUCCESS); 100 } 101 102 PAM_EXTERN int 103 pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused, 104 int argc __unused, const char *argv[] __unused) 105 { 106 107 return (PAM_SUCCESS); 108 } 109 110 PAM_MODULE_ENTRY("pam_chroot"); 111