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