1 /*- 2 * Copyright (c) 2001,2003 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("$FreeBSD$"); 37 38 #include <sys/types.h> 39 #include <sys/wait.h> 40 41 #include <errno.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <unistd.h> 46 47 #include <security/pam_appl.h> 48 #include <security/pam_modules.h> 49 #include <security/openpam.h> 50 51 #define ENV_ITEM(n) { (n), #n } 52 static struct { 53 int item; 54 const char *name; 55 } env_items[] = { 56 ENV_ITEM(PAM_SERVICE), 57 ENV_ITEM(PAM_USER), 58 ENV_ITEM(PAM_TTY), 59 ENV_ITEM(PAM_RHOST), 60 ENV_ITEM(PAM_RUSER), 61 }; 62 63 static int 64 _pam_exec(pam_handle_t *pamh __unused, int flags __unused, 65 int argc, const char *argv[]) 66 { 67 int envlen, i, nitems, pam_err, status; 68 char *env, **envlist, **tmp; 69 volatile int childerr; 70 pid_t pid; 71 72 if (argc < 1) 73 return (PAM_SERVICE_ERR); 74 75 /* 76 * XXX For additional credit, divert child's stdin/stdout/stderr 77 * to the conversation function. 78 */ 79 80 /* 81 * Set up the child's environment list. It consists of the PAM 82 * environment, plus a few hand-picked PAM items. 83 */ 84 envlist = pam_getenvlist(pamh); 85 for (envlen = 0; envlist[envlen] != NULL; ++envlen) 86 /* nothing */ ; 87 nitems = sizeof(env_items) / sizeof(*env_items); 88 tmp = realloc(envlist, (envlen + nitems + 1) * sizeof(*envlist)); 89 if (tmp == NULL) { 90 openpam_free_envlist(envlist); 91 return (PAM_BUF_ERR); 92 } 93 envlist = tmp; 94 for (i = 0; i < nitems; ++i) { 95 const void *item; 96 char *envstr; 97 98 pam_err = pam_get_item(pamh, env_items[i].item, &item); 99 if (pam_err != PAM_SUCCESS || item == NULL) 100 continue; 101 asprintf(&envstr, "%s=%s", env_items[i].name, item); 102 if (envstr == NULL) { 103 openpam_free_envlist(envlist); 104 return (PAM_BUF_ERR); 105 } 106 envlist[envlen++] = envstr; 107 envlist[envlen] = NULL; 108 } 109 110 /* 111 * Fork and run the command. By using vfork() instead of fork(), 112 * we can distinguish between an execve() failure and a non-zero 113 * exit code from the command. 114 */ 115 childerr = 0; 116 if ((pid = vfork()) == 0) { 117 execve(argv[0], (char * const *)argv, (char * const *)envlist); 118 childerr = errno; 119 _exit(1); 120 } 121 openpam_free_envlist(envlist); 122 if (pid == -1) { 123 openpam_log(PAM_LOG_ERROR, "vfork(): %m"); 124 return (PAM_SYSTEM_ERR); 125 } 126 if (waitpid(pid, &status, 0) == -1) { 127 openpam_log(PAM_LOG_ERROR, "waitpid(): %m"); 128 return (PAM_SYSTEM_ERR); 129 } 130 if (childerr != 0) { 131 openpam_log(PAM_LOG_ERROR, "execve(): %m"); 132 return (PAM_SYSTEM_ERR); 133 } 134 if (WIFSIGNALED(status)) { 135 openpam_log(PAM_LOG_ERROR, "%s caught signal %d%s", 136 argv[0], WTERMSIG(status), 137 WCOREDUMP(status) ? " (core dumped)" : ""); 138 return (PAM_SYSTEM_ERR); 139 } 140 if (!WIFEXITED(status)) { 141 openpam_log(PAM_LOG_ERROR, "unknown status 0x%x", status); 142 return (PAM_SYSTEM_ERR); 143 } 144 if (WEXITSTATUS(status) != 0) { 145 openpam_log(PAM_LOG_ERROR, "%s returned code %d", 146 argv[0], WEXITSTATUS(status)); 147 return (PAM_SYSTEM_ERR); 148 } 149 return (PAM_SUCCESS); 150 } 151 152 PAM_EXTERN int 153 pam_sm_authenticate(pam_handle_t *pamh, int flags, 154 int argc, const char *argv[]) 155 { 156 157 return (_pam_exec(pamh, flags, argc, argv)); 158 } 159 160 PAM_EXTERN int 161 pam_sm_setcred(pam_handle_t *pamh, int flags, 162 int argc, const char *argv[]) 163 { 164 165 return (_pam_exec(pamh, flags, argc, argv)); 166 } 167 168 PAM_EXTERN int 169 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags, 170 int argc, const char *argv[]) 171 { 172 173 return (_pam_exec(pamh, flags, argc, argv)); 174 } 175 176 PAM_EXTERN int 177 pam_sm_open_session(pam_handle_t *pamh, int flags, 178 int argc, const char *argv[]) 179 { 180 181 return (_pam_exec(pamh, flags, argc, argv)); 182 } 183 184 PAM_EXTERN int 185 pam_sm_close_session(pam_handle_t *pamh, int flags, 186 int argc, const char *argv[]) 187 { 188 189 return (_pam_exec(pamh, flags, argc, argv)); 190 } 191 192 PAM_EXTERN int 193 pam_sm_chauthtok(pam_handle_t *pamh, int flags, 194 int argc, const char *argv[]) 195 { 196 197 return (_pam_exec(pamh, flags, argc, argv)); 198 } 199 200 PAM_MODULE_ENTRY("pam_exec"); 201