1 /*- 2 * Copyright (c) 2002-2003 Networks Associates Technology, Inc. 3 * Copyright (c) 2004-2011 Dag-Erling Smørgrav 4 * All rights reserved. 5 * 6 * This software was developed for the FreeBSD Project by ThinkSec AS and 7 * Network Associates Laboratories, the Security Research Division of 8 * Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 9 * ("CBOSS"), as part of the DARPA CHATS research program. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. The name of the author may not be used to endorse or promote 20 * products derived from this software without specific prior written 21 * permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifdef HAVE_CONFIG_H 37 # include "config.h" 38 #endif 39 40 #include <sys/param.h> 41 42 #include <dlfcn.h> 43 #include <errno.h> 44 #include <fcntl.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <unistd.h> 49 50 #include <security/pam_appl.h> 51 52 #include "openpam_impl.h" 53 #include "openpam_asprintf.h" 54 #include "openpam_ctype.h" 55 #include "openpam_dlfunc.h" 56 57 #ifndef RTLD_NOW 58 #define RTLD_NOW RTLD_LAZY 59 #endif 60 61 /* 62 * OpenPAM internal 63 * 64 * Perform sanity checks and attempt to load a module 65 */ 66 67 #ifdef HAVE_FDLOPEN 68 static void * 69 try_dlopen(const char *modfn) 70 { 71 void *dlh; 72 int fd; 73 74 openpam_log(PAM_LOG_LIBDEBUG, "dlopen(%s)", modfn); 75 if ((fd = open(modfn, O_RDONLY)) < 0) { 76 if (errno != ENOENT) 77 openpam_log(PAM_LOG_ERROR, "%s: %m", modfn); 78 return (NULL); 79 } 80 if (OPENPAM_FEATURE(VERIFY_MODULE_FILE) && 81 openpam_check_desc_owner_perms(modfn, fd) != 0) { 82 close(fd); 83 return (NULL); 84 } 85 if ((dlh = fdlopen(fd, RTLD_NOW)) == NULL) { 86 openpam_log(PAM_LOG_ERROR, "%s: %s", modfn, dlerror()); 87 close(fd); 88 errno = 0; 89 return (NULL); 90 } 91 close(fd); 92 return (dlh); 93 } 94 #else 95 static void * 96 try_dlopen(const char *modfn) 97 { 98 int check_module_file; 99 void *dlh; 100 101 openpam_log(PAM_LOG_LIBDEBUG, "dlopen(%s)", modfn); 102 openpam_get_feature(OPENPAM_VERIFY_MODULE_FILE, 103 &check_module_file); 104 if (check_module_file && 105 openpam_check_path_owner_perms(modfn) != 0) 106 return (NULL); 107 if ((dlh = dlopen(modfn, RTLD_NOW)) == NULL) { 108 openpam_log(PAM_LOG_ERROR, "%s: %s", modfn, dlerror()); 109 errno = 0; 110 return (NULL); 111 } 112 return (dlh); 113 } 114 #endif 115 116 /* 117 * Try to load a module from the suggested location. 118 */ 119 static pam_module_t * 120 try_module(const char *modpath) 121 { 122 const pam_module_t *dlmodule; 123 pam_module_t *module; 124 int i, serrno; 125 126 if ((module = calloc(1, sizeof *module)) == NULL || 127 (module->path = strdup(modpath)) == NULL || 128 (module->dlh = try_dlopen(modpath)) == NULL) 129 goto err; 130 dlmodule = dlsym(module->dlh, "_pam_module"); 131 for (i = 0; i < PAM_NUM_PRIMITIVES; ++i) { 132 if (dlmodule) { 133 module->func[i] = dlmodule->func[i]; 134 } else { 135 module->func[i] = (pam_func_t)dlfunc(module->dlh, 136 pam_sm_func_name[i]); 137 /* 138 * This openpam_log() call is a major source of 139 * log spam, and the cases that matter are caught 140 * and logged in openpam_dispatch(). This would 141 * be less problematic if dlerror() returned an 142 * error code so we could log an error only when 143 * dlfunc() failed for a reason other than "no 144 * such symbol". 145 */ 146 #if 0 147 if (module->func[i] == NULL) 148 openpam_log(PAM_LOG_LIBDEBUG, "%s: %s(): %s", 149 modpath, pam_sm_func_name[i], dlerror()); 150 #endif 151 } 152 } 153 return (module); 154 err: 155 serrno = errno; 156 if (module != NULL) { 157 if (module->dlh != NULL) 158 dlclose(module->dlh); 159 if (module->path != NULL) 160 FREE(module->path); 161 FREE(module); 162 } 163 errno = serrno; 164 if (serrno != 0 && serrno != ENOENT) 165 openpam_log(PAM_LOG_ERROR, "%s: %m", modpath); 166 errno = serrno; 167 return (NULL); 168 } 169 170 /* 171 * OpenPAM internal 172 * 173 * Locate a dynamically linked module 174 */ 175 176 pam_module_t * 177 openpam_dynamic(const char *modname) 178 { 179 pam_module_t *module; 180 char modpath[PATH_MAX]; 181 const char **path, *p; 182 int has_so, has_ver; 183 int dot, len; 184 185 /* 186 * Simple case: module name contains path separator(s) 187 */ 188 if (strchr(modname, '/') != NULL) { 189 /* 190 * Absolute paths are not allowed if RESTRICT_MODULE_NAME 191 * is in effect (default off). Relative paths are never 192 * allowed. 193 */ 194 if (OPENPAM_FEATURE(RESTRICT_MODULE_NAME) || 195 modname[0] != '/') { 196 openpam_log(PAM_LOG_ERROR, 197 "invalid module name: %s", modname); 198 return (NULL); 199 } 200 return (try_module(modname)); 201 } 202 203 /* 204 * Check for .so and version sufixes 205 */ 206 p = strchr(modname, '\0'); 207 has_ver = has_so = 0; 208 while (is_digit(*p)) 209 --p; 210 if (*p == '.' && *++p != '\0') { 211 /* found a numeric suffix */ 212 has_ver = 1; 213 /* assume that .so is either present or unneeded */ 214 has_so = 1; 215 } else if (*p == '\0' && p >= modname + sizeof PAM_SOEXT && 216 strcmp(p - sizeof PAM_SOEXT + 1, PAM_SOEXT) == 0) { 217 /* found .so suffix */ 218 has_so = 1; 219 } 220 221 /* 222 * Complicated case: search for the module in the usual places. 223 */ 224 for (path = openpam_module_path; *path != NULL; ++path) { 225 /* 226 * Assemble the full path, including the version suffix. Take 227 * note of where the suffix begins so we can cut it off later. 228 */ 229 if (has_ver) 230 len = snprintf(modpath, sizeof modpath, "%s/%s%n", 231 *path, modname, &dot); 232 else if (has_so) 233 len = snprintf(modpath, sizeof modpath, "%s/%s%n.%d", 234 *path, modname, &dot, LIB_MAJ); 235 else 236 len = snprintf(modpath, sizeof modpath, "%s/%s%s%n.%d", 237 *path, modname, PAM_SOEXT, &dot, LIB_MAJ); 238 /* check for overflow */ 239 if (len < 0 || (unsigned int)len >= sizeof modpath) { 240 errno = ENOENT; 241 continue; 242 } 243 /* try the versioned path */ 244 if ((module = try_module(modpath)) != NULL) 245 return (module); 246 if (errno == ENOENT && modpath[dot] != '\0') { 247 /* no luck, try the unversioned path */ 248 modpath[dot] = '\0'; 249 if ((module = try_module(modpath)) != NULL) 250 return (module); 251 } 252 } 253 254 /* :( */ 255 return (NULL); 256 } 257 258 /* 259 * NOPARSE 260 */ 261