pam_chroot.c revision 112857
1/*- 2 * Copyright (c) 2003 Networks Associates Technology, Inc. 3 * All rights reserved. 4 * 5 * This software was developed for the FreeBSD Project by ThinkSec AS and 6 * NAI Labs, the Security Research Division of Network Associates, Inc. 7 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the 8 * 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 35#include <sys/cdefs.h> 36__FBSDID("$FreeBSD: head/lib/libpam/modules/pam_chroot/pam_chroot.c 112857 2003-03-30 22:58:23Z des $"); 37 38#include <sys/param.h> 39 40#include <pwd.h> 41#include <stdio.h> 42#include <string.h> 43#include <unistd.h> 44 45#define PAM_SM_SESSION 46 47#include <security/pam_appl.h> 48#include <security/pam_modules.h> 49#include <security/openpam.h> 50 51PAM_EXTERN int 52pam_sm_open_session(pam_handle_t *pamh, int flags __unused, 53 int argc __unused, const char *argv[] __unused) 54{ 55 const char *dir, *end, *user; 56 struct passwd *pwd; 57 char buf[PATH_MAX]; 58 59 if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS || 60 user == NULL || (pwd = getpwnam(user)) == NULL) 61 return (PAM_SESSION_ERR); 62 if (pwd->pw_uid == 0 && !openpam_get_option(pamh, "also_root")) 63 return (PAM_SUCCESS); 64 if (pwd->pw_dir == NULL) 65 return (PAM_SESSION_ERR); 66 if ((end = strstr(pwd->pw_dir, "/./")) != NULL) { 67 if (snprintf(buf, sizeof(buf), "%.*s", 68 (int)(end - pwd->pw_dir), pwd->pw_dir) > (int)sizeof(buf)) { 69 openpam_log(PAM_LOG_ERROR, 70 "%s's home directory is too long", user); 71 return (PAM_SESSION_ERR); 72 } 73 dir = buf; 74 } else if ((dir = openpam_get_option(pamh, "dir")) == NULL) { 75 if (openpam_get_option(pamh, "always")) { 76 openpam_log(PAM_LOG_ERROR, 77 "%s has no chroot directory", user); 78 return (PAM_SESSION_ERR); 79 } 80 return (PAM_SUCCESS); 81 } 82 83 openpam_log(PAM_LOG_DEBUG, "chrooting %s to %s", dir, user); 84 85 if (chroot(dir) == -1) { 86 openpam_log(PAM_LOG_ERROR, "chroot(): %m"); 87 return (PAM_SESSION_ERR); 88 } 89 chdir("/"); 90 return (PAM_SUCCESS); 91} 92 93PAM_EXTERN int 94pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused, 95 int argc __unused, const char *argv[] __unused) 96{ 97 98 return (PAM_SUCCESS); 99} 100 101PAM_MODULE_ENTRY("pam_chroot"); 102