1 /* 2 * Copyright (c) 1997-2000, 2003-2005 Kungliga Tekniska H�gskolan 3 * (Royal Institute of Technology, Stockholm, Sweden). 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * 3. Neither the name of the Institute nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #include "kadm5_locl.h" 35 #include "kadm5-pwcheck.h" 36 37 RCSID("$Id: password_quality.c 17595 2006-05-30 21:51:55Z lha $"); 38 39 #ifdef HAVE_SYS_WAIT_H 40 #include <sys/wait.h> 41 #endif 42 #ifdef HAVE_DLFCN_H 43 #include <dlfcn.h> 44 #endif 45 46 static int 47 min_length_passwd_quality (krb5_context context, 48 krb5_principal principal, 49 krb5_data *pwd, 50 const char *opaque, 51 char *message, 52 size_t length) 53 { 54 uint32_t min_length = krb5_config_get_int_default(context, NULL, 6, 55 "password_quality", 56 "min_length", 57 NULL); 58 59 if (pwd->length < min_length) { 60 strlcpy(message, "Password too short", length); 61 return 1; 62 } else 63 return 0; 64 } 65 66 static const char * 67 min_length_passwd_quality_v0 (krb5_context context, 68 krb5_principal principal, 69 krb5_data *pwd) 70 { 71 static char message[1024]; 72 int ret; 73 74 message[0] = '\0'; 75 76 ret = min_length_passwd_quality(context, principal, pwd, NULL, 77 message, sizeof(message)); 78 if (ret) 79 return message; 80 return NULL; 81 } 82 83 84 static int 85 char_class_passwd_quality (krb5_context context, 86 krb5_principal principal, 87 krb5_data *pwd, 88 const char *opaque, 89 char *message, 90 size_t length) 91 { 92 const char *classes[] = { 93 "ABCDEFGHIJKLMNOPQRSTUVWXYZ", 94 "abcdefghijklmnopqrstuvwxyz", 95 "1234567890", 96 "!@#$%^&*()/?<>,.{[]}\\|'~`\" " 97 }; 98 int i, counter = 0, req_classes; 99 size_t len; 100 char *pw; 101 102 req_classes = krb5_config_get_int_default(context, NULL, 3, 103 "password_quality", 104 "min_classes", 105 NULL); 106 107 len = pwd->length + 1; 108 pw = malloc(len); 109 if (pw == NULL) { 110 strlcpy(message, "out of memory", length); 111 return 1; 112 } 113 strlcpy(pw, pwd->data, len); 114 len = strlen(pw); 115 116 for (i = 0; i < sizeof(classes)/sizeof(classes[0]); i++) { 117 if (strcspn(pw, classes[i]) < len) 118 counter++; 119 } 120 memset(pw, 0, pwd->length + 1); 121 free(pw); 122 if (counter < req_classes) { 123 snprintf(message, length, 124 "Password doesn't meet complexity requirement.\n" 125 "Add more characters from the following classes:\n" 126 "1. English uppercase characters (A through Z)\n" 127 "2. English lowercase characters (a through z)\n" 128 "3. Base 10 digits (0 through 9)\n" 129 "4. Nonalphanumeric characters (e.g., !, $, #, %%)"); 130 return 1; 131 } 132 return 0; 133 } 134 135 static int 136 external_passwd_quality (krb5_context context, 137 krb5_principal principal, 138 krb5_data *pwd, 139 const char *opaque, 140 char *message, 141 size_t length) 142 { 143 krb5_error_code ret; 144 const char *program; 145 char *p; 146 pid_t child; 147 int status; 148 char reply[1024]; 149 FILE *in = NULL, *out = NULL, *error = NULL; 150 151 if (memchr(pwd->data, pwd->length, '\n') != NULL) { 152 snprintf(message, length, "password contains newline, " 153 "not valid for external test"); 154 return 1; 155 } 156 157 program = krb5_config_get_string(context, NULL, 158 "password_quality", 159 "external_program", 160 NULL); 161 if (program == NULL) { 162 snprintf(message, length, "external password quality " 163 "program not configured"); 164 return 1; 165 } 166 167 ret = krb5_unparse_name(context, principal, &p); 168 if (ret) { 169 strlcpy(message, "out of memory", length); 170 return 1; 171 } 172 173 child = pipe_execv(&in, &out, &error, program, p, NULL); 174 if (child < 0) { 175 snprintf(message, length, "external password quality " 176 "program failed to execute for principal %s", p); 177 free(p); 178 return 1; 179 } 180 181 fprintf(in, "principal: %s\n" 182 "new-password: %.*s\n" 183 "end\n", 184 p, (int)pwd->length, (char *)pwd->data); 185 186 fclose(in); 187 188 if (fgets(reply, sizeof(reply), out) == NULL) { 189 190 if (fgets(reply, sizeof(reply), error) == NULL) { 191 snprintf(message, length, "external password quality " 192 "program failed without error"); 193 194 } else { 195 reply[strcspn(reply, "\n")] = '\0'; 196 snprintf(message, length, "External password quality " 197 "program failed: %s", reply); 198 } 199 200 fclose(out); 201 fclose(error); 202 waitpid(child, &status, 0); 203 return 1; 204 } 205 reply[strcspn(reply, "\n")] = '\0'; 206 207 fclose(out); 208 fclose(error); 209 210 if (waitpid(child, &status, 0) < 0) { 211 snprintf(message, length, "external program failed: %s", reply); 212 free(p); 213 return 1; 214 } 215 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { 216 snprintf(message, length, "external program failed: %s", reply); 217 free(p); 218 return 1; 219 } 220 221 if (strcmp(reply, "APPROVED") != 0) { 222 snprintf(message, length, "%s", reply); 223 free(p); 224 return 1; 225 } 226 227 free(p); 228 229 return 0; 230 } 231 232 233 static kadm5_passwd_quality_check_func_v0 passwd_quality_check = 234 min_length_passwd_quality_v0; 235 236 struct kadm5_pw_policy_check_func builtin_funcs[] = { 237 { "minimum-length", min_length_passwd_quality }, 238 { "character-class", char_class_passwd_quality }, 239 { "external-check", external_passwd_quality }, 240 { NULL } 241 }; 242 struct kadm5_pw_policy_verifier builtin_verifier = { 243 "builtin", 244 KADM5_PASSWD_VERSION_V1, 245 "Heimdal builtin", 246 builtin_funcs 247 }; 248 249 static struct kadm5_pw_policy_verifier **verifiers; 250 static int num_verifiers; 251 252 /* 253 * setup the password quality hook 254 */ 255 256 #ifndef RTLD_NOW 257 #define RTLD_NOW 0 258 #endif 259 260 void 261 kadm5_setup_passwd_quality_check(krb5_context context, 262 const char *check_library, 263 const char *check_function) 264 { 265 #ifdef HAVE_DLOPEN 266 void *handle; 267 void *sym; 268 int *version; 269 const char *tmp; 270 271 if(check_library == NULL) { 272 tmp = krb5_config_get_string(context, NULL, 273 "password_quality", 274 "check_library", 275 NULL); 276 if(tmp != NULL) 277 check_library = tmp; 278 } 279 if(check_function == NULL) { 280 tmp = krb5_config_get_string(context, NULL, 281 "password_quality", 282 "check_function", 283 NULL); 284 if(tmp != NULL) 285 check_function = tmp; 286 } 287 if(check_library != NULL && check_function == NULL) 288 check_function = "passwd_check"; 289 290 if(check_library == NULL) 291 return; 292 handle = dlopen(check_library, RTLD_NOW); 293 if(handle == NULL) { 294 krb5_warnx(context, "failed to open `%s'", check_library); 295 return; 296 } 297 version = dlsym(handle, "version"); 298 if(version == NULL) { 299 krb5_warnx(context, 300 "didn't find `version' symbol in `%s'", check_library); 301 dlclose(handle); 302 return; 303 } 304 if(*version != KADM5_PASSWD_VERSION_V0) { 305 krb5_warnx(context, 306 "version of loaded library is %d (expected %d)", 307 *version, KADM5_PASSWD_VERSION_V0); 308 dlclose(handle); 309 return; 310 } 311 sym = dlsym(handle, check_function); 312 if(sym == NULL) { 313 krb5_warnx(context, 314 "didn't find `%s' symbol in `%s'", 315 check_function, check_library); 316 dlclose(handle); 317 return; 318 } 319 passwd_quality_check = (kadm5_passwd_quality_check_func_v0) sym; 320 #endif /* HAVE_DLOPEN */ 321 } 322 323 #ifdef HAVE_DLOPEN 324 325 static krb5_error_code 326 add_verifier(krb5_context context, const char *check_library) 327 { 328 struct kadm5_pw_policy_verifier *v, **tmp; 329 void *handle; 330 int i; 331 332 handle = dlopen(check_library, RTLD_NOW); 333 if(handle == NULL) { 334 krb5_warnx(context, "failed to open `%s'", check_library); 335 return ENOENT; 336 } 337 v = dlsym(handle, "kadm5_password_verifier"); 338 if(v == NULL) { 339 krb5_warnx(context, 340 "didn't find `kadm5_password_verifier' symbol " 341 "in `%s'", check_library); 342 dlclose(handle); 343 return ENOENT; 344 } 345 if(v->version != KADM5_PASSWD_VERSION_V1) { 346 krb5_warnx(context, 347 "version of loaded library is %d (expected %d)", 348 v->version, KADM5_PASSWD_VERSION_V1); 349 dlclose(handle); 350 return EINVAL; 351 } 352 for (i = 0; i < num_verifiers; i++) { 353 if (strcmp(v->name, verifiers[i]->name) == 0) 354 break; 355 } 356 if (i < num_verifiers) { 357 krb5_warnx(context, "password verifier library `%s' is already loaded", 358 v->name); 359 dlclose(handle); 360 return 0; 361 } 362 363 tmp = realloc(verifiers, (num_verifiers + 1) * sizeof(*verifiers)); 364 if (tmp == NULL) { 365 krb5_warnx(context, "out of memory"); 366 dlclose(handle); 367 return 0; 368 } 369 verifiers = tmp; 370 verifiers[num_verifiers] = v; 371 num_verifiers++; 372 373 return 0; 374 } 375 376 #endif 377 378 krb5_error_code 379 kadm5_add_passwd_quality_verifier(krb5_context context, 380 const char *check_library) 381 { 382 #ifdef HAVE_DLOPEN 383 384 if(check_library == NULL) { 385 krb5_error_code ret; 386 char **tmp; 387 388 tmp = krb5_config_get_strings(context, NULL, 389 "password_quality", 390 "policy_libraries", 391 NULL); 392 if(tmp == NULL) 393 return 0; 394 395 while(tmp) { 396 ret = add_verifier(context, *tmp); 397 if (ret) 398 return ret; 399 tmp++; 400 } 401 } 402 return add_verifier(context, check_library); 403 #else 404 return 0; 405 #endif /* HAVE_DLOPEN */ 406 } 407 408 /* 409 * 410 */ 411 412 static const struct kadm5_pw_policy_check_func * 413 find_func(krb5_context context, const char *name) 414 { 415 const struct kadm5_pw_policy_check_func *f; 416 char *module = NULL; 417 const char *p, *func; 418 int i; 419 420 p = strchr(name, ':'); 421 if (p) { 422 func = p + 1; 423 module = strndup(name, p - name); 424 if (module == NULL) 425 return NULL; 426 } else 427 func = name; 428 429 /* Find module in loaded modules first */ 430 for (i = 0; i < num_verifiers; i++) { 431 if (module && strcmp(module, verifiers[i]->name) != 0) 432 continue; 433 for (f = verifiers[i]->funcs; f->name ; f++) 434 if (strcmp(name, f->name) == 0) { 435 if (module) 436 free(module); 437 return f; 438 } 439 } 440 /* Lets try try the builtin modules */ 441 if (module == NULL || strcmp(module, "builtin") == 0) { 442 for (f = builtin_verifier.funcs; f->name ; f++) 443 if (strcmp(func, f->name) == 0) { 444 if (module) 445 free(module); 446 return f; 447 } 448 } 449 if (module) 450 free(module); 451 return NULL; 452 } 453 454 const char * 455 kadm5_check_password_quality (krb5_context context, 456 krb5_principal principal, 457 krb5_data *pwd_data) 458 { 459 const struct kadm5_pw_policy_check_func *proc; 460 static char error_msg[1024]; 461 const char *msg; 462 char **v, **vp; 463 int ret; 464 465 /* 466 * Check if we should use the old version of policy function. 467 */ 468 469 v = krb5_config_get_strings(context, NULL, 470 "password_quality", 471 "policies", 472 NULL); 473 if (v == NULL) { 474 msg = (*passwd_quality_check) (context, principal, pwd_data); 475 krb5_set_error_string(context, "password policy failed: %s", msg); 476 return msg; 477 } 478 479 error_msg[0] = '\0'; 480 481 msg = NULL; 482 for(vp = v; *vp; vp++) { 483 proc = find_func(context, *vp); 484 if (proc == NULL) { 485 msg = "failed to find password verifier function"; 486 krb5_set_error_string(context, "Failed to find password policy " 487 "function: %s", *vp); 488 break; 489 } 490 ret = (proc->func)(context, principal, pwd_data, NULL, 491 error_msg, sizeof(error_msg)); 492 if (ret) { 493 krb5_set_error_string(context, "Password policy " 494 "%s failed with %s", 495 proc->name, error_msg); 496 msg = error_msg; 497 break; 498 } 499 } 500 krb5_config_free_strings(v); 501 502 /* If the default quality check isn't used, lets check that the 503 * old quality function the user have set too */ 504 if (msg == NULL && passwd_quality_check != min_length_passwd_quality_v0) { 505 msg = (*passwd_quality_check) (context, principal, pwd_data); 506 if (msg) 507 krb5_set_error_string(context, "(old) password policy " 508 "failed with %s", msg); 509 510 } 511 return msg; 512 } 513