1 /* $NetBSD: pam_chroot.c,v 1.4 2005/04/19 03:15:34 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 1.4 2005/04/19 03:15:34 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 <unistd.h> 50 51 #define PAM_SM_SESSION 52 53 #include <security/pam_appl.h> 54 #include <security/pam_modules.h> 55 #include <security/openpam.h> 56 57 PAM_EXTERN int 58 pam_sm_open_session(pam_handle_t *pamh, int flags __unused, 59 int argc __unused, const char *argv[] __unused) 60 { 61 const char *dir, *end, *cwd, *user; 62 struct passwd *pwd, pwres; 63 char buf[PATH_MAX]; 64 char pwbuf[1024]; 65 66 if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS || 67 user == NULL || 68 getpwnam_r(user, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 || 69 pwd == NULL) 70 return (PAM_SESSION_ERR); 71 if (pwd->pw_uid == 0 && !openpam_get_option(pamh, "also_root")) 72 return (PAM_SUCCESS); 73 if (pwd->pw_dir == NULL) 74 return (PAM_SESSION_ERR); 75 if ((end = strstr(pwd->pw_dir, "/./")) != NULL) { 76 if (snprintf(buf, sizeof(buf), "%.*s", 77 (int)(end - pwd->pw_dir), pwd->pw_dir) > (int)sizeof(buf)) { 78 openpam_log(PAM_LOG_ERROR, 79 "%s's home directory is too long", user); 80 return (PAM_SESSION_ERR); 81 } 82 dir = buf; 83 cwd = end + 2; 84 } else if ((dir = openpam_get_option(pamh, "dir")) != NULL) { 85 if ((cwd = openpam_get_option(pamh, "cwd")) == NULL) 86 cwd = "/"; 87 } else { 88 if (openpam_get_option(pamh, "always")) { 89 openpam_log(PAM_LOG_ERROR, 90 "%s has no chroot directory", user); 91 return (PAM_SESSION_ERR); 92 } 93 return (PAM_SUCCESS); 94 } 95 96 openpam_log(PAM_LOG_DEBUG, "chrooting %s to %s", dir, user); 97 98 if (chroot(dir) == -1) { 99 openpam_log(PAM_LOG_ERROR, "chroot(): %m"); 100 return (PAM_SESSION_ERR); 101 } 102 if (chdir(cwd) == -1) { 103 openpam_log(PAM_LOG_ERROR, "chdir(): %m"); 104 return (PAM_SESSION_ERR); 105 } 106 pam_setenv(pamh, "HOME", cwd, 1); 107 return (PAM_SUCCESS); 108 } 109 110 PAM_EXTERN int 111 pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused, 112 int argc __unused, const char *argv[] __unused) 113 { 114 115 return (PAM_SUCCESS); 116 } 117 118 PAM_MODULE_ENTRY("pam_chroot"); 119