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 * $OpenPAM: openpam_dynamic.c 938 2017-04-30 21:34:42Z des $ 36 */ 37 38 #ifdef HAVE_CONFIG_H 39 # include "config.h" 40 #endif 41 42 #include <sys/param.h> 43 44 #include <dlfcn.h> 45 #include <errno.h> 46 #include <fcntl.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <unistd.h> 51 52 #include <security/pam_appl.h> 53 54 #include "openpam_impl.h" 55 #include "openpam_asprintf.h" 56 #include "openpam_ctype.h" 57 #include "openpam_dlfunc.h" 58 59 #ifndef RTLD_NOW 60 #define RTLD_NOW RTLD_LAZY 61 #endif 62 63 /* 64 * OpenPAM internal 65 * 66 * Perform sanity checks and attempt to load a module 67 */ 68 69 #ifdef HAVE_FDLOPEN 70 static void * 71 try_dlopen(const char *modfn) 72 { 73 void *dlh; 74 int fd; 75 76 openpam_log(PAM_LOG_LIBDEBUG, "dlopen(%s)", modfn); 77 if ((fd = open(modfn, O_RDONLY)) < 0) { 78 if (errno != ENOENT) 79 openpam_log(PAM_LOG_ERROR, "%s: %m", modfn); 80 return (NULL); 81 } 82 if (OPENPAM_FEATURE(VERIFY_MODULE_FILE) && 83 openpam_check_desc_owner_perms(modfn, fd) != 0) { 84 close(fd); 85 return (NULL); 86 } 87 if ((dlh = fdlopen(fd, RTLD_NOW)) == NULL) { 88 openpam_log(PAM_LOG_ERROR, "%s: %s", modfn, dlerror()); 89 close(fd); 90 errno = 0; 91 return (NULL); 92 } 93 close(fd); 94 return (dlh); 95 } 96 #else 97 static void * 98 try_dlopen(const char *modfn) 99 { 100 int check_module_file; 101 void *dlh; 102 103 openpam_log(PAM_LOG_LIBDEBUG, "dlopen(%s)", modfn); 104 openpam_get_feature(OPENPAM_VERIFY_MODULE_FILE, 105 &check_module_file); 106 if (check_module_file && 107 openpam_check_path_owner_perms(modfn) != 0) 108 return (NULL); 109 if ((dlh = dlopen(modfn, RTLD_NOW)) == NULL) { 110 openpam_log(PAM_LOG_ERROR, "%s: %s", modfn, dlerror()); 111 errno = 0; 112 return (NULL); 113 } 114 return (dlh); 115 } 116 #endif 117 118 /* 119 * Try to load a module from the suggested location. 120 */ 121 static pam_module_t * 122 try_module(const char *modpath) 123 { 124 const pam_module_t *dlmodule; 125 pam_module_t *module; 126 int i, serrno; 127 128 if ((module = calloc(1, sizeof *module)) == NULL || 129 (module->path = strdup(modpath)) == NULL || 130 (module->dlh = try_dlopen(modpath)) == NULL) 131 goto err; 132 dlmodule = dlsym(module->dlh, "_pam_module"); 133 for (i = 0; i < PAM_NUM_PRIMITIVES; ++i) { 134 if (dlmodule) { 135 module->func[i] = dlmodule->func[i]; 136 } else { 137 module->func[i] = (pam_func_t)dlfunc(module->dlh, 138 pam_sm_func_name[i]); 139 /* 140 * This openpam_log() call is a major source of 141 * log spam, and the cases that matter are caught 142 * and logged in openpam_dispatch(). This would 143 * be less problematic if dlerror() returned an 144 * error code so we could log an error only when 145 * dlfunc() failed for a reason other than "no 146 * such symbol". 147 */ 148 #if 0 149 if (module->func[i] == NULL) 150 openpam_log(PAM_LOG_LIBDEBUG, "%s: %s(): %s", 151 modpath, pam_sm_func_name[i], dlerror()); 152 #endif 153 } 154 } 155 return (module); 156 err: 157 serrno = errno; 158 if (module != NULL) { 159 if (module->dlh != NULL) 160 dlclose(module->dlh); 161 if (module->path != NULL) 162 FREE(module->path); 163 FREE(module); 164 } 165 errno = serrno; 166 if (serrno != 0 && serrno != ENOENT) 167 openpam_log(PAM_LOG_ERROR, "%s: %m", modpath); 168 errno = serrno; 169 return (NULL); 170 } 171 172 /* 173 * OpenPAM internal 174 * 175 * Locate a dynamically linked module 176 */ 177 178 pam_module_t * 179 openpam_dynamic(const char *modname) 180 { 181 pam_module_t *module; 182 char modpath[PATH_MAX]; 183 const char **path, *p; 184 int has_so, has_ver; 185 int dot, len; 186 187 /* 188 * Simple case: module name contains path separator(s) 189 */ 190 if (strchr(modname, '/') != NULL) { 191 /* 192 * Absolute paths are not allowed if RESTRICT_MODULE_NAME 193 * is in effect (default off). Relative paths are never 194 * allowed. 195 */ 196 if (OPENPAM_FEATURE(RESTRICT_MODULE_NAME) || 197 modname[0] != '/') { 198 openpam_log(PAM_LOG_ERROR, 199 "invalid module name: %s", modname); 200 return (NULL); 201 } 202 return (try_module(modname)); 203 } 204 205 /* 206 * Check for .so and version sufixes 207 */ 208 p = strchr(modname, '\0'); 209 has_ver = has_so = 0; 210 while (is_digit(*p)) 211 --p; 212 if (*p == '.' && *++p != '\0') { 213 /* found a numeric suffix */ 214 has_ver = 1; 215 /* assume that .so is either present or unneeded */ 216 has_so = 1; 217 } else if (*p == '\0' && p >= modname + sizeof PAM_SOEXT && 218 strcmp(p - sizeof PAM_SOEXT + 1, PAM_SOEXT) == 0) { 219 /* found .so suffix */ 220 has_so = 1; 221 } 222 223 /* 224 * Complicated case: search for the module in the usual places. 225 */ 226 for (path = openpam_module_path; *path != NULL; ++path) { 227 /* 228 * Assemble the full path, including the version suffix. Take 229 * note of where the suffix begins so we can cut it off later. 230 */ 231 if (has_ver) 232 len = snprintf(modpath, sizeof modpath, "%s/%s%n", 233 *path, modname, &dot); 234 else if (has_so) 235 len = snprintf(modpath, sizeof modpath, "%s/%s%n.%d", 236 *path, modname, &dot, LIB_MAJ); 237 else 238 len = snprintf(modpath, sizeof modpath, "%s/%s%s%n.%d", 239 *path, modname, PAM_SOEXT, &dot, LIB_MAJ); 240 /* check for overflow */ 241 if (len < 0 || (unsigned int)len >= sizeof modpath) { 242 errno = ENOENT; 243 continue; 244 } 245 /* try the versioned path */ 246 if ((module = try_module(modpath)) != NULL) 247 return (module); 248 if (errno == ENOENT && modpath[dot] != '\0') { 249 /* no luck, try the unversioned path */ 250 modpath[dot] = '\0'; 251 if ((module = try_module(modpath)) != NULL) 252 return (module); 253 } 254 } 255 256 /* :( */ 257 return (NULL); 258 } 259 260 /* 261 * NOPARSE 262 */ 263