crypto/rand/rand_lib.c

   1 /*
   2  * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (the "License").  You may not use
   5  * this file except in compliance with the License.  You can obtain a copy
   6  * in the file LICENSE in the source distribution or at
   7  * https://www.openssl.org/source/license.html
   8  */
   9
  10 #include <stdio.h>
  11 #include <time.h>
  12 #include "internal/cryptlib.h"
  13 #include <openssl/opensslconf.h>
  14 #include "internal/rand_int.h"
  15 #include <openssl/engine.h>
  16 #include "internal/thread_once.h"
  17 #include "rand_lcl.h"
  18
  19 #ifndef OPENSSL_NO_ENGINE
  20 /* non-NULL if default_RAND_meth is ENGINE-provided */
  21 static ENGINE *funct_ref;
  22 static CRYPTO_RWLOCK *rand_engine_lock;
  23 #endif
  24 static CRYPTO_RWLOCK *rand_meth_lock;
  25 static const RAND_METHOD *default_RAND_meth;
  26 static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT;
  27
  28 int rand_fork_count;
  29
  30 #ifdef OPENSSL_RAND_SEED_RDTSC
  31 /*
  32  * IMPORTANT NOTE:  It is not currently possible to use this code
  33  * because we are not sure about the amount of randomness it provides.
  34  * Some SP900 tests have been run, but there is internal skepticism.
  35  * So for now this code is not used.
  36  */
  37 # error "RDTSC enabled?  Should not be possible!"
  38
  39 /*
  40  * Acquire entropy from high-speed clock
  41  *
  42  * Since we get some randomness from the low-order bits of the
  43  * high-speed clock, it can help.
  44  *
  45  * Returns the total entropy count, if it exceeds the requested
  46  * entropy count. Otherwise, returns an entropy count of 0.
  47  */
  48 size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool)
  49 {
  50     unsigned char c;
  51     int i;
  52
  53     if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) {
  54         for (i = 0; i < TSC_READ_COUNT; i++) {
  55             c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
  56             RAND_POOL_add(pool, &c, 1, 4);
  57         }
  58     }
  59     return RAND_POOL_entropy_available(pool);
  60 }
  61 #endif
  62
  63 #ifdef OPENSSL_RAND_SEED_RDCPU
  64 size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len);
  65 size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len);
  66
  67 extern unsigned int OPENSSL_ia32cap_P[];
  68
  69 /*
  70  * Acquire entropy using Intel-specific cpu instructions
  71  *
  72  * Uses the RDSEED instruction if available, otherwise uses
  73  * RDRAND if available.
  74  *
  75  * For the differences between RDSEED and RDRAND, and why RDSEED
  76  * is the preferred choice, see https://goo.gl/oK3KcN
  77  *
  78  * Returns the total entropy count, if it exceeds the requested
  79  * entropy count. Otherwise, returns an entropy count of 0.
  80  */
  81 size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool)
  82 {
  83     size_t bytes_needed;
  84     unsigned char *buffer;
  85
  86     bytes_needed = RAND_POOL_bytes_needed(pool, 8 /*entropy_per_byte*/);
  87     if (bytes_needed > 0) {
  88         buffer = RAND_POOL_add_begin(pool, bytes_needed);
  89
  90         if (buffer != NULL) {
  91
  92             /* If RDSEED is available, use that. */
  93             if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
  94                 if (OPENSSL_ia32_rdseed_bytes(buffer, bytes_needed)
  95                     == bytes_needed)
  96                     return RAND_POOL_add_end(pool,
  97                                              bytes_needed,
  98                                              8 * bytes_needed);
  99             }
 100
 101             /* Second choice is RDRAND. */
 102             if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
 103                 if (OPENSSL_ia32_rdrand_bytes(buffer, bytes_needed)
 104                     == bytes_needed)
 105                     return RAND_POOL_add_end(pool,
 106                                              bytes_needed,
 107                                              8 * bytes_needed);
 108             }
 109
 110             return RAND_POOL_add_end(pool, 0, 0);
 111         }
 112     }
 113
 114     return RAND_POOL_entropy_available(pool);
 115 }
 116 #endif
 117
 118
 119 /*
 120  * Implements the get_entropy() callback (see RAND_DRBG_set_callbacks())
 121  *
 122  * If the DRBG has a parent, then the required amount of entropy input
 123  * is fetched using the parent's RAND_DRBG_generate().
 124  *
 125  * Otherwise, the entropy is polled from the system entropy sources
 126  * using RAND_POOL_acquire_entropy().
 127  *
 128  * If a random pool has been added to the DRBG using RAND_add(), then
 129  * its entropy will be used up first.
 130  */
 131 size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
 132                         unsigned char **pout,
 133                         int entropy, size_t min_len, size_t max_len)
 134 {
 135     size_t ret = 0;
 136     size_t entropy_available = 0;
 137     RAND_POOL *pool = RAND_POOL_new(entropy, min_len, max_len);
 138
 139     if (pool == NULL)
 140         return 0;
 141
 142     if (drbg->pool) {
 143         RAND_POOL_add(pool,
 144                       RAND_POOL_buffer(drbg->pool),
 145                       RAND_POOL_length(drbg->pool),
 146                       RAND_POOL_entropy(drbg->pool));
 147         RAND_POOL_free(drbg->pool);
 148         drbg->pool = NULL;
 149     }
 150
 151     if (drbg->parent) {
 152         size_t bytes_needed = RAND_POOL_bytes_needed(pool, 8);
 153         unsigned char *buffer = RAND_POOL_add_begin(pool, bytes_needed);
 154
 155         if (buffer != NULL) {
 156             size_t bytes = 0;
 157
 158             /*
 159              * Get random from parent, include our state as additional input.
 160              * Our lock is already held, but we need to lock our parent before
 161              * generating bits from it.
 162              */
 163             if (drbg->parent->lock)
 164                 CRYPTO_THREAD_write_lock(drbg->parent->lock);
 165             if (RAND_DRBG_generate(drbg->parent,
 166                                    buffer, bytes_needed,
 167                                    0,
 168                                    (unsigned char *)drbg, sizeof(*drbg)) != 0)
 169                 bytes = bytes_needed;
 170             if (drbg->parent->lock)
 171                 CRYPTO_THREAD_unlock(drbg->parent->lock);
 172
 173             entropy_available = RAND_POOL_add_end(pool, bytes, 8 * bytes);
 174         }
 175
 176     } else {
 177         /* Get entropy by polling system entropy sources. */
 178         entropy_available = RAND_POOL_acquire_entropy(pool);
 179     }
 180
 181     if (entropy_available > 0) {
 182         ret   = RAND_POOL_length(pool);
 183         *pout = RAND_POOL_detach(pool);
 184     }
 185
 186     RAND_POOL_free(pool);
 187     return ret;
 188 }
 189
 190
 191 /*
 192  * Implements the cleanup_entropy() callback (see RAND_DRBG_set_callbacks())
 193  *
 194  */
 195 void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
 196                                unsigned char *out, size_t outlen)
 197 {
 198     OPENSSL_secure_clear_free(out, outlen);
 199 }
 200
 201 void rand_fork()
 202 {
 203     rand_fork_count++;
 204 }
 205
 206 DEFINE_RUN_ONCE_STATIC(do_rand_init)
 207 {
 208     int ret = 1;
 209
 210 #ifndef OPENSSL_NO_ENGINE
 211     rand_engine_lock = CRYPTO_THREAD_glock_new("rand_engine");
 212     ret &= rand_engine_lock != NULL;
 213 #endif
 214     rand_meth_lock = CRYPTO_THREAD_glock_new("rand_meth");
 215     ret &= rand_meth_lock != NULL;
 216
 217     return ret;
 218 }
 219
 220 void rand_cleanup_int(void)
 221 {
 222     const RAND_METHOD *meth = default_RAND_meth;
 223
 224     if (meth != NULL && meth->cleanup != NULL)
 225         meth->cleanup();
 226     RAND_set_rand_method(NULL);
 227 #ifndef OPENSSL_NO_ENGINE
 228     CRYPTO_THREAD_lock_free(rand_engine_lock);
 229 #endif
 230     CRYPTO_THREAD_lock_free(rand_meth_lock);
 231 }
 232
 233 /*
 234  * RAND_poll() reseeds the default RNG using random input
 235  *
 236  * The random input is obtained from polling various entropy
 237  * sources which depend on the operating system and are
 238  * configurable via the --with-rand-seed configure option.
 239  */
 240 int RAND_poll(void)
 241 {
 242     int ret = 0;
 243
 244     RAND_POOL *pool = NULL;
 245
 246     const RAND_METHOD *meth = RAND_get_rand_method();
 247
 248     if (meth == RAND_OpenSSL()) {
 249         /* fill random pool and seed the default DRBG */
 250         RAND_DRBG *drbg = RAND_DRBG_get0_global();
 251
 252         if (drbg == NULL)
 253             return 0;
 254
 255         CRYPTO_THREAD_write_lock(drbg->lock);
 256         ret = rand_drbg_restart(drbg, NULL, 0, 0);
 257         CRYPTO_THREAD_unlock(drbg->lock);
 258
 259         return ret;
 260
 261     } else {
 262         /* fill random pool and seed the current legacy RNG */
 263         pool = RAND_POOL_new(RAND_DRBG_STRENGTH,
 264                              RAND_DRBG_STRENGTH / 8,
 265                              DRBG_MINMAX_FACTOR * (RAND_DRBG_STRENGTH / 8));
 266         if (pool == NULL)
 267             return 0;
 268
 269         if (RAND_POOL_acquire_entropy(pool) == 0)
 270             goto err;
 271
 272         if (meth->add == NULL
 273             || meth->add(RAND_POOL_buffer(pool),
 274                          RAND_POOL_length(pool),
 275                          (RAND_POOL_entropy(pool) / 8.0)) == 0)
 276             goto err;
 277
 278         ret = 1;
 279     }
 280
 281 err:
 282     RAND_POOL_free(pool);
 283     return ret;
 284 }
 285
 286 /*
 287  * The 'random pool' acts as a dumb container for collecting random
 288  * input from various entropy sources. The pool has no knowledge about
 289  * whether its randomness is fed into a legacy RAND_METHOD via RAND_add()
 290  * or into a new style RAND_DRBG. It is the callers duty to 1) initialize the
 291  * random pool, 2) pass it to the polling callbacks, 3) seed the RNG, and
 292  * 4) cleanup the random pool again.
 293  *
 294  * The random pool contains no locking mechanism because its scope and
 295  * lifetime is intended to be restricted to a single stack frame.
 296  */
 297 struct rand_pool_st {
 298     unsigned char *buffer;  /* points to the beginning of the random pool */
 299     size_t len; /* current number of random bytes contained in the pool */
 300
 301     size_t min_len; /* minimum number of random bytes requested */
 302     size_t max_len; /* maximum number of random bytes (allocated buffer size) */
 303     size_t entropy; /* current entropy count in bits */
 304     size_t requested_entropy; /* requested entropy count in bits */
 305 };
 306
 307 /*
 308  * Allocate memory and initialize a new random pool
 309  */
 310
 311 RAND_POOL *RAND_POOL_new(int entropy, size_t min_len, size_t max_len)
 312 {
 313     RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
 314
 315     if (pool == NULL) {
 316         RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
 317         goto err;
 318     }
 319
 320     pool->min_len = min_len;
 321     pool->max_len = max_len;
 322
 323     pool->buffer = OPENSSL_secure_zalloc(pool->max_len);
 324     if (pool->buffer == NULL) {
 325         RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
 326         goto err;
 327     }
 328
 329     pool->requested_entropy = entropy;
 330
 331     return pool;
 332
 333 err:
 334     OPENSSL_free(pool);
 335     return NULL;
 336 }
 337
 338 /*
 339  * Free |pool|, securely erasing its buffer.
 340  */
 341 void RAND_POOL_free(RAND_POOL *pool)
 342 {
 343     if (pool == NULL)
 344         return;
 345
 346     OPENSSL_secure_clear_free(pool->buffer, pool->max_len);
 347     OPENSSL_free(pool);
 348 }
 349
 350 /*
 351  * Return the |pool|'s buffer to the caller (readonly).
 352  */
 353 const unsigned char *RAND_POOL_buffer(RAND_POOL *pool)
 354 {
 355     return pool->buffer;
 356 }
 357
 358 /*
 359  * Return the |pool|'s entropy to the caller.
 360  */
 361 size_t RAND_POOL_entropy(RAND_POOL *pool)
 362 {
 363     return pool->entropy;
 364 }
 365
 366 /*
 367  * Return the |pool|'s buffer length to the caller.
 368  */
 369 size_t RAND_POOL_length(RAND_POOL *pool)
 370 {
 371     return pool->len;
 372 }
 373
 374 /*
 375  * Detach the |pool| buffer and return it to the caller.
 376  * It's the responsibility of the caller to free the buffer
 377  * using OPENSSL_secure_clear_free().
 378  */
 379 unsigned char *RAND_POOL_detach(RAND_POOL *pool)
 380 {
 381     unsigned char *ret = pool->buffer;
 382     pool->buffer = NULL;
 383     return ret;
 384 }
 385
 386
 387 /*
 388  * If every byte of the input contains |entropy_per_bytes| bits of entropy,
 389  * how many bytes does one need to obtain at least |bits| bits of entropy?
 390  */
 391 #define ENTROPY_TO_BYTES(bits, entropy_per_bytes) \
 392     (((bits) + ((entropy_per_bytes) - 1))/(entropy_per_bytes))
 393
 394
 395 /*
 396  * Checks whether the |pool|'s entropy is available to the caller.
 397  * This is the case when entropy count and buffer length are high enough.
 398  * Returns
 399  *
 400  *  |entropy|  if the entropy count and buffer size is large enough
 401  *      0      otherwise
 402  */
 403 size_t RAND_POOL_entropy_available(RAND_POOL *pool)
 404 {
 405     if (pool->entropy < pool->requested_entropy)
 406         return 0;
 407
 408     if (pool->len < pool->min_len)
 409         return 0;
 410
 411     return pool->entropy;
 412 }
 413
 414 /*
 415  * Returns the (remaining) amount of entropy needed to fill
 416  * the random pool.
 417  */
 418
 419 size_t RAND_POOL_entropy_needed(RAND_POOL *pool)
 420 {
 421     if (pool->entropy < pool->requested_entropy)
 422         return pool->requested_entropy - pool->entropy;
 423
 424     return 0;
 425 }
 426
 427 /*
 428  * Returns the number of bytes needed to fill the pool, assuming
 429  * the input has 'entropy_per_byte' entropy bits per byte.
 430  * In case of an error, 0 is returned.
 431  */
 432
 433 size_t RAND_POOL_bytes_needed(RAND_POOL *pool, unsigned int entropy_per_byte)
 434 {
 435     size_t bytes_needed;
 436     size_t entropy_needed = RAND_POOL_entropy_needed(pool);
 437
 438     if (entropy_per_byte < 1 || entropy_per_byte > 8) {
 439         RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_ARGUMENT_OUT_OF_RANGE);
 440         return 0;
 441     }
 442
 443     bytes_needed = ENTROPY_TO_BYTES(entropy_needed, entropy_per_byte);
 444
 445     if (bytes_needed > pool->max_len - pool->len) {
 446         /* not enough space left */
 447         RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_RANDOM_POOL_OVERFLOW);
 448         return 0;
 449     }
 450
 451     if (pool->len < pool->min_len &&
 452         bytes_needed < pool->min_len - pool->len)
 453         /* to meet the min_len requirement */
 454         bytes_needed = pool->min_len - pool->len;
 455
 456     return bytes_needed;
 457 }
 458
 459 /* Returns the remaining number of bytes available */
 460 size_t RAND_POOL_bytes_remaining(RAND_POOL *pool)
 461 {
 462     return pool->max_len - pool->len;
 463 }
 464
 465 /*
 466  * Add random bytes to the random pool.
 467  *
 468  * It is expected that the |buffer| contains |len| bytes of
 469  * random input which contains at least |entropy| bits of
 470  * randomness.
 471  *
 472  * Return available amount of entropy after this operation.
 473  * (see RAND_POOL_entropy_available(pool))
 474  */
 475 size_t RAND_POOL_add(RAND_POOL *pool,
 476                      const unsigned char *buffer, size_t len, size_t entropy)
 477 {
 478     if (len > pool->max_len - pool->len) {
 479         RANDerr(RAND_F_RAND_POOL_ADD, RAND_R_ENTROPY_INPUT_TOO_LONG);
 480         return 0;
 481     }
 482
 483     if (len > 0) {
 484         memcpy(pool->buffer + pool->len, buffer, len);
 485         pool->len += len;
 486         pool->entropy += entropy;
 487     }
 488
 489     return RAND_POOL_entropy_available(pool);
 490 }
 491
 492 /*
 493  * Start to add random bytes to the random pool in-place.
 494  *
 495  * Reserves the next |len| bytes for adding random bytes in-place
 496  * and returns a pointer to the buffer.
 497  * The caller is allowed to copy up to |len| bytes into the buffer.
 498  * If |len| == 0 this is considered a no-op and a NULL pointer
 499  * is returned without producing an error message.
 500  *
 501  * After updating the buffer, RAND_POOL_add_end() needs to be called
 502  * to finish the udpate operation (see next comment).
 503  */
 504 unsigned char *RAND_POOL_add_begin(RAND_POOL *pool, size_t len)
 505 {
 506     if (len == 0)
 507         return NULL;
 508
 509     if (len > pool->max_len - pool->len) {
 510         RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, RAND_R_RANDOM_POOL_OVERFLOW);
 511         return NULL;
 512     }
 513
 514     return pool->buffer + pool->len;
 515 }
 516
 517 /*
 518  * Finish to add random bytes to the random pool in-place.
 519  *
 520  * Finishes an in-place update of the random pool started by
 521  * RAND_POOL_add_begin() (see previous comment).
 522  * It is expected that |len| bytes of random input have been added
 523  * to the buffer which contain at least |entropy| bits of randomness.
 524  * It is allowed to add less bytes than originally reserved.
 525  */
 526 size_t RAND_POOL_add_end(RAND_POOL *pool, size_t len, size_t entropy)
 527 {
 528     if (len > pool->max_len - pool->len) {
 529         RANDerr(RAND_F_RAND_POOL_ADD_END, RAND_R_RANDOM_POOL_OVERFLOW);
 530         return 0;
 531     }
 532
 533     if (len > 0) {
 534         pool->len += len;
 535         pool->entropy += entropy;
 536     }
 537
 538     return RAND_POOL_entropy_available(pool);
 539 }
 540
 541 int RAND_set_rand_method(const RAND_METHOD *meth)
 542 {
 543     if (!RUN_ONCE(&rand_init, do_rand_init))
 544         return 0;
 545
 546     CRYPTO_THREAD_write_lock(rand_meth_lock);
 547 #ifndef OPENSSL_NO_ENGINE
 548     ENGINE_finish(funct_ref);
 549     funct_ref = NULL;
 550 #endif
 551     default_RAND_meth = meth;
 552     CRYPTO_THREAD_unlock(rand_meth_lock);
 553     return 1;
 554 }
 555
 556 const RAND_METHOD *RAND_get_rand_method(void)
 557 {
 558     const RAND_METHOD *tmp_meth = NULL;
 559
 560     if (!RUN_ONCE(&rand_init, do_rand_init))
 561         return NULL;
 562
 563     CRYPTO_THREAD_write_lock(rand_meth_lock);
 564     if (default_RAND_meth == NULL) {
 565 #ifndef OPENSSL_NO_ENGINE
 566         ENGINE *e;
 567
 568         /* If we have an engine that can do RAND, use it. */
 569         if ((e = ENGINE_get_default_RAND()) != NULL
 570                 && (tmp_meth = ENGINE_get_RAND(e)) != NULL) {
 571             funct_ref = e;
 572             default_RAND_meth = tmp_meth;
 573         } else {
 574             ENGINE_finish(e);
 575             default_RAND_meth = &rand_meth;
 576         }
 577 #else
 578         default_RAND_meth = &rand_meth;
 579 #endif
 580     }
 581     tmp_meth = default_RAND_meth;
 582     CRYPTO_THREAD_unlock(rand_meth_lock);
 583     return tmp_meth;
 584 }
 585
 586 #ifndef OPENSSL_NO_ENGINE
 587 int RAND_set_rand_engine(ENGINE *engine)
 588 {
 589     const RAND_METHOD *tmp_meth = NULL;
 590
 591     if (!RUN_ONCE(&rand_init, do_rand_init))
 592         return 0;
 593
 594     if (engine != NULL) {
 595         if (!ENGINE_init(engine))
 596             return 0;
 597         tmp_meth = ENGINE_get_RAND(engine);
 598         if (tmp_meth == NULL) {
 599             ENGINE_finish(engine);
 600             return 0;
 601         }
 602     }
 603     CRYPTO_THREAD_write_lock(rand_engine_lock);
 604     /* This function releases any prior ENGINE so call it first */
 605     RAND_set_rand_method(tmp_meth);
 606     funct_ref = engine;
 607     CRYPTO_THREAD_unlock(rand_engine_lock);
 608     return 1;
 609 }
 610 #endif
 611
 612 void RAND_seed(const void *buf, int num)
 613 {
 614     const RAND_METHOD *meth = RAND_get_rand_method();
 615
 616     if (meth->seed != NULL)
 617         meth->seed(buf, num);
 618 }
 619
 620 void RAND_add(const void *buf, int num, double randomness)
 621 {
 622     const RAND_METHOD *meth = RAND_get_rand_method();
 623
 624     if (meth->add != NULL)
 625         meth->add(buf, num, randomness);
 626 }
 627
 628 /*
 629  * This function is not part of RAND_METHOD, so if we're not using
 630  * the default method, then just call RAND_bytes().  Otherwise make
 631  * sure we're instantiated and use the private DRBG.
 632  */
 633 int RAND_priv_bytes(unsigned char *buf, int num)
 634 {
 635     const RAND_METHOD *meth = RAND_get_rand_method();
 636     RAND_DRBG *drbg;
 637     int ret;
 638
 639     if (meth != RAND_OpenSSL())
 640         return RAND_bytes(buf, num);
 641
 642     drbg = RAND_DRBG_get0_priv_global();
 643     if (drbg == NULL)
 644         return 0;
 645
 646     /* We have to lock the DRBG before generating bits from it. */
 647     CRYPTO_THREAD_write_lock(drbg->lock);
 648     ret = RAND_DRBG_generate(drbg, buf, num, 0, NULL, 0);
 649     CRYPTO_THREAD_unlock(drbg->lock);
 650     return ret;
 651 }
 652
 653 int RAND_bytes(unsigned char *buf, int num)
 654 {
 655     const RAND_METHOD *meth = RAND_get_rand_method();
 656
 657     if (meth->bytes != NULL)
 658         return meth->bytes(buf, num);
 659     RANDerr(RAND_F_RAND_BYTES, RAND_R_FUNC_NOT_IMPLEMENTED);
 660     return -1;
 661 }
 662
 663 #if OPENSSL_API_COMPAT < 0x10100000L
 664 int RAND_pseudo_bytes(unsigned char *buf, int num)
 665 {
 666     const RAND_METHOD *meth = RAND_get_rand_method();
 667
 668     if (meth->pseudorand != NULL)
 669         return meth->pseudorand(buf, num);
 670     return -1;
 671 }
 672 #endif
 673
 674 int RAND_status(void)
 675 {
 676     const RAND_METHOD *meth = RAND_get_rand_method();
 677
 678     if (meth->status != NULL)
 679         return meth->status();
 680     return 0;
 681 }