1 /* $NetBSD: pam_exec.c,v 1.3 2005/02/26 16:03:58 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 2001,2003 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_exec/pam_exec.c,v 1.4 2005/02/01 10:37:07 des Exp $"); 40 #else 41 __RCSID("$NetBSD: pam_exec.c,v 1.3 2005/02/26 16:03:58 thorpej Exp $"); 42 #endif 43 44 #include <sys/types.h> 45 #include <sys/wait.h> 46 47 #include <errno.h> 48 #include <stdlib.h> 49 #include <stdio.h> 50 #include <string.h> 51 #include <unistd.h> 52 53 #include <security/pam_appl.h> 54 #include <security/pam_modules.h> 55 #include <security/openpam.h> 56 57 #define ENV_ITEM(n) { (n), #n } 58 static struct { 59 int item; 60 const char *name; 61 } env_items[] = { 62 ENV_ITEM(PAM_SERVICE), 63 ENV_ITEM(PAM_USER), 64 ENV_ITEM(PAM_TTY), 65 ENV_ITEM(PAM_RHOST), 66 ENV_ITEM(PAM_RUSER), 67 }; 68 69 /* 70 * XXX Until we import OpenPAM Feterita. 71 */ 72 static void 73 openpam_free_envlist(char **envlist) 74 { 75 char **env; 76 77 for (env = envlist; *env != NULL; ++env) 78 free(*env); 79 free(envlist); 80 } 81 82 static int 83 _pam_exec(pam_handle_t *pamh __unused, int flags __unused, 84 int argc, const char *argv[]) 85 { 86 int childerr, envlen, i, nitems, pam_err, status; 87 char **envlist, **tmp; 88 pid_t pid; 89 90 if (argc < 1) 91 return (PAM_SERVICE_ERR); 92 93 /* 94 * XXX For additional credit, divert child's stdin/stdout/stderr 95 * to the conversation function. 96 */ 97 98 /* 99 * Set up the child's environment list. It consists of the PAM 100 * environment, plus a few hand-picked PAM items. 101 */ 102 envlist = pam_getenvlist(pamh); 103 for (envlen = 0; envlist[envlen] != NULL; ++envlen) 104 /* nothing */ ; 105 nitems = sizeof(env_items) / sizeof(*env_items); 106 tmp = realloc(envlist, (envlen + nitems + 1) * sizeof **envlist); 107 if (tmp == NULL) { 108 openpam_free_envlist(envlist); 109 return (PAM_BUF_ERR); 110 } 111 envlist = tmp; 112 for (i = 0; i < nitems; ++i) { 113 const void *item; 114 char *envstr; 115 116 pam_err = pam_get_item(pamh, env_items[i].item, &item); 117 if (pam_err != PAM_SUCCESS || item == NULL) 118 continue; 119 asprintf(&envstr, "%s=%s", env_items[i].name, 120 (const char *)item); 121 if (envstr == NULL) { 122 openpam_free_envlist(envlist); 123 return (PAM_BUF_ERR); 124 } 125 envlist[envlen++] = envstr; 126 envlist[envlen] = NULL; 127 } 128 129 /* 130 * Fork and run the command. By using vfork() instead of fork(), 131 * we can distinguish between an execve() failure and a non-zero 132 * exit code from the command. 133 */ 134 childerr = 0; 135 if ((pid = vfork()) == 0) { 136 /*LINTED const cast*/ 137 execve(argv[0], (char **)__UNCONST(argv), envlist); 138 childerr = errno; 139 _exit(1); 140 } 141 openpam_free_envlist(envlist); 142 if (pid == -1) { 143 openpam_log(PAM_LOG_ERROR, "vfork(): %m"); 144 return (PAM_SYSTEM_ERR); 145 } 146 if (waitpid(pid, &status, 0) == -1) { 147 openpam_log(PAM_LOG_ERROR, "waitpid(): %m"); 148 return (PAM_SYSTEM_ERR); 149 } 150 if (childerr != 0) { 151 openpam_log(PAM_LOG_ERROR, "execve(): %m"); 152 return (PAM_SYSTEM_ERR); 153 } 154 if (WIFSIGNALED(status)) { 155 openpam_log(PAM_LOG_ERROR, "%s caught signal %d%s", 156 argv[0], WTERMSIG(status), 157 WCOREDUMP(status) ? " (core dumped)" : ""); 158 return (PAM_SYSTEM_ERR); 159 } 160 if (!WIFEXITED(status)) { 161 openpam_log(PAM_LOG_ERROR, "unknown status 0x%x", status); 162 return (PAM_SYSTEM_ERR); 163 } 164 if (WEXITSTATUS(status) != 0) { 165 openpam_log(PAM_LOG_ERROR, "%s returned code %d", 166 argv[0], WEXITSTATUS(status)); 167 return (PAM_SYSTEM_ERR); 168 } 169 return (PAM_SUCCESS); 170 } 171 172 PAM_EXTERN int 173 pam_sm_authenticate(pam_handle_t *pamh, int flags, 174 int argc, const char *argv[]) 175 { 176 177 return (_pam_exec(pamh, flags, argc, argv)); 178 } 179 180 PAM_EXTERN int 181 pam_sm_setcred(pam_handle_t *pamh, int flags, 182 int argc, const char *argv[]) 183 { 184 185 return (_pam_exec(pamh, flags, argc, argv)); 186 } 187 188 PAM_EXTERN int 189 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags, 190 int argc, const char *argv[]) 191 { 192 193 return (_pam_exec(pamh, flags, argc, argv)); 194 } 195 196 PAM_EXTERN int 197 pam_sm_open_session(pam_handle_t *pamh, int flags, 198 int argc, const char *argv[]) 199 { 200 201 return (_pam_exec(pamh, flags, argc, argv)); 202 } 203 204 PAM_EXTERN int 205 pam_sm_close_session(pam_handle_t *pamh, int flags, 206 int argc, const char *argv[]) 207 { 208 209 return (_pam_exec(pamh, flags, argc, argv)); 210 } 211 212 PAM_EXTERN int 213 pam_sm_chauthtok(pam_handle_t *pamh, int flags, 214 int argc, const char *argv[]) 215 { 216 217 return (_pam_exec(pamh, flags, argc, argv)); 218 } 219 220 PAM_MODULE_ENTRY("pam_exec"); 221