release/src-rt-6.x.4708/router/dropbear/common-algo.c

   1 /*
   2  * Dropbear SSH
   3  *
   4  * Copyright (c) 2002,2003 Matt Johnston
   5  * Copyright (c) 2004 by Mihnea Stoenescu
   6  * All rights reserved.
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24  * SOFTWARE. */
  25
  26 #include "includes.h"
  27 #include "algo.h"
  28 #include "session.h"
  29 #include "dbutil.h"
  30 #include "kex.h"
  31 #include "ltc_prng.h"
  32 #include "ecc.h"
  33
  34 /* This file (algo.c) organises the ciphers which can be used, and is used to
  35  * decide which ciphers/hashes/compression/signing to use during key exchange*/
  36
  37 static int void_cipher(const unsigned char* in, unsigned char* out,
  38                 unsigned long len, void* UNUSED(cipher_state)) {
  39         if (in != out) {
  40                 memmove(out, in, len);
  41         }
  42         return CRYPT_OK;
  43 }
  44
  45 static int void_start(int UNUSED(cipher), const unsigned char* UNUSED(IV),
  46                         const unsigned char* UNUSED(key),
  47                         int UNUSED(keylen), int UNUSED(num_rounds), void* UNUSED(cipher_state)) {
  48         return CRYPT_OK;
  49 }
  50
  51 /* Mappings for ciphers, parameters are
  52    {&cipher_desc, keysize, blocksize} */
  53
  54 /* Remember to add new ciphers/hashes to regciphers/reghashes too */
  55
  56 #ifdef DROPBEAR_AES256
  57 static const struct dropbear_cipher dropbear_aes256 =
  58         {&aes_desc, 32, 16};
  59 #endif
  60 #ifdef DROPBEAR_AES128
  61 static const struct dropbear_cipher dropbear_aes128 =
  62         {&aes_desc, 16, 16};
  63 #endif
  64 #ifdef DROPBEAR_BLOWFISH
  65 static const struct dropbear_cipher dropbear_blowfish =
  66         {&blowfish_desc, 16, 8};
  67 #endif
  68 #ifdef DROPBEAR_TWOFISH256
  69 static const struct dropbear_cipher dropbear_twofish256 =
  70         {&twofish_desc, 32, 16};
  71 #endif
  72 #ifdef DROPBEAR_TWOFISH128
  73 static const struct dropbear_cipher dropbear_twofish128 =
  74         {&twofish_desc, 16, 16};
  75 #endif
  76 #ifdef DROPBEAR_3DES
  77 static const struct dropbear_cipher dropbear_3des =
  78         {&des3_desc, 24, 8};
  79 #endif
  80
  81 /* used to indicate no encryption, as defined in rfc2410 */
  82 const struct dropbear_cipher dropbear_nocipher =
  83         {NULL, 16, 8};
  84
  85 /* A few void* s are required to silence warnings
  86  * about the symmetric_CBC vs symmetric_CTR cipher_state pointer */
  87 #ifdef DROPBEAR_ENABLE_CBC_MODE
  88 const struct dropbear_cipher_mode dropbear_mode_cbc =
  89         {(void*)cbc_start, (void*)cbc_encrypt, (void*)cbc_decrypt};
  90 #endif /* DROPBEAR_ENABLE_CBC_MODE */
  91
  92 const struct dropbear_cipher_mode dropbear_mode_none =
  93         {void_start, void_cipher, void_cipher};
  94
  95 #ifdef DROPBEAR_ENABLE_CTR_MODE
  96 /* a wrapper to make ctr_start and cbc_start look the same */
  97 static int dropbear_big_endian_ctr_start(int cipher,
  98                 const unsigned char *IV,
  99                 const unsigned char *key, int keylen,
 100                 int num_rounds, symmetric_CTR *ctr) {
 101         return ctr_start(cipher, IV, key, keylen, num_rounds, CTR_COUNTER_BIG_ENDIAN, ctr);
 102 }
 103 const struct dropbear_cipher_mode dropbear_mode_ctr =
 104         {(void*)dropbear_big_endian_ctr_start, (void*)ctr_encrypt, (void*)ctr_decrypt};
 105 #endif /* DROPBEAR_ENABLE_CTR_MODE */
 106
 107 /* Mapping of ssh hashes to libtomcrypt hashes, including keysize etc.
 108    {&hash_desc, keysize, hashsize} */
 109
 110 #ifdef DROPBEAR_SHA1_HMAC
 111 static const struct dropbear_hash dropbear_sha1 =
 112         {&sha1_desc, 20, 20};
 113 #endif
 114 #ifdef DROPBEAR_SHA1_96_HMAC
 115 static const struct dropbear_hash dropbear_sha1_96 =
 116         {&sha1_desc, 20, 12};
 117 #endif
 118 #ifdef DROPBEAR_SHA2_256_HMAC
 119 static const struct dropbear_hash dropbear_sha2_256 =
 120         {&sha256_desc, 32, 32};
 121 #endif
 122 #ifdef DROPBEAR_SHA2_512_HMAC
 123 static const struct dropbear_hash dropbear_sha2_512 =
 124         {&sha512_desc, 64, 64};
 125 #endif
 126 #ifdef DROPBEAR_MD5_HMAC
 127 static const struct dropbear_hash dropbear_md5 =
 128         {&md5_desc, 16, 16};
 129 #endif
 130
 131 const struct dropbear_hash dropbear_nohash =
 132         {NULL, 16, 0}; /* used initially */
 133
 134
 135 /* The following map ssh names to internal values.
 136  * The ordering here is important for the client - the first mode
 137  * that is also supported by the server will get used. */
 138
 139 algo_type sshciphers[] = {
 140 #ifdef DROPBEAR_ENABLE_CTR_MODE
 141 #ifdef DROPBEAR_AES128
 142         {"aes128-ctr", 0, &dropbear_aes128, 1, &dropbear_mode_ctr},
 143 #endif
 144 #ifdef DROPBEAR_AES256
 145         {"aes256-ctr", 0, &dropbear_aes256, 1, &dropbear_mode_ctr},
 146 #endif
 147 #ifdef DROPBEAR_TWOFISH_CTR
 148 /* twofish ctr is conditional as it hasn't been tested for interoperability, see options.h */
 149 #ifdef DROPBEAR_TWOFISH256
 150         {"twofish256-ctr", 0, &dropbear_twofish256, 1, &dropbear_mode_ctr},
 151 #endif
 152 #ifdef DROPBEAR_TWOFISH128
 153         {"twofish128-ctr", 0, &dropbear_twofish128, 1, &dropbear_mode_ctr},
 154 #endif
 155 #endif /* DROPBEAR_TWOFISH_CTR */
 156 #endif /* DROPBEAR_ENABLE_CTR_MODE */
 157
 158 #ifdef DROPBEAR_ENABLE_CBC_MODE
 159 #ifdef DROPBEAR_AES128
 160         {"aes128-cbc", 0, &dropbear_aes128, 1, &dropbear_mode_cbc},
 161 #endif
 162 #ifdef DROPBEAR_AES256
 163         {"aes256-cbc", 0, &dropbear_aes256, 1, &dropbear_mode_cbc},
 164 #endif
 165 #ifdef DROPBEAR_TWOFISH256
 166         {"twofish256-cbc", 0, &dropbear_twofish256, 1, &dropbear_mode_cbc},
 167         {"twofish-cbc", 0, &dropbear_twofish256, 1, &dropbear_mode_cbc},
 168 #endif
 169 #ifdef DROPBEAR_TWOFISH128
 170         {"twofish128-cbc", 0, &dropbear_twofish128, 1, &dropbear_mode_cbc},
 171 #endif
 172 #ifdef DROPBEAR_3DES
 173         {"3des-ctr", 0, &dropbear_3des, 1, &dropbear_mode_ctr},
 174 #endif
 175 #ifdef DROPBEAR_3DES
 176         {"3des-cbc", 0, &dropbear_3des, 1, &dropbear_mode_cbc},
 177 #endif
 178 #ifdef DROPBEAR_BLOWFISH
 179         {"blowfish-cbc", 0, &dropbear_blowfish, 1, &dropbear_mode_cbc},
 180 #endif
 181 #endif /* DROPBEAR_ENABLE_CBC_MODE */
 182 #ifdef DROPBEAR_NONE_CIPHER
 183         {"none", 0, (void*)&dropbear_nocipher, 1, &dropbear_mode_none},
 184 #endif
 185         {NULL, 0, NULL, 0, NULL}
 186 };
 187
 188 algo_type sshhashes[] = {
 189 #ifdef DROPBEAR_SHA1_96_HMAC
 190         {"hmac-sha1-96", 0, &dropbear_sha1_96, 1, NULL},
 191 #endif
 192 #ifdef DROPBEAR_SHA1_HMAC
 193         {"hmac-sha1", 0, &dropbear_sha1, 1, NULL},
 194 #endif
 195 #ifdef DROPBEAR_SHA2_256_HMAC
 196         {"hmac-sha2-256", 0, &dropbear_sha2_256, 1, NULL},
 197 #endif
 198 #ifdef DROPBEAR_SHA2_512_HMAC
 199         {"hmac-sha2-512", 0, &dropbear_sha2_512, 1, NULL},
 200 #endif
 201 #ifdef DROPBEAR_MD5_HMAC
 202         {"hmac-md5", 0, (void*)&dropbear_md5, 1, NULL},
 203 #endif
 204 #ifdef DROPBEAR_NONE_INTEGRITY
 205         {"none", 0, (void*)&dropbear_nohash, 1, NULL},
 206 #endif
 207         {NULL, 0, NULL, 0, NULL}
 208 };
 209
 210 #ifndef DISABLE_ZLIB
 211 algo_type ssh_compress[] = {
 212         {"zlib@openssh.com", DROPBEAR_COMP_ZLIB_DELAY, NULL, 1, NULL},
 213         {"zlib", DROPBEAR_COMP_ZLIB, NULL, 1, NULL},
 214         {"none", DROPBEAR_COMP_NONE, NULL, 1, NULL},
 215         {NULL, 0, NULL, 0, NULL}
 216 };
 217
 218 algo_type ssh_delaycompress[] = {
 219         {"zlib@openssh.com", DROPBEAR_COMP_ZLIB_DELAY, NULL, 1, NULL},
 220         {"none", DROPBEAR_COMP_NONE, NULL, 1, NULL},
 221         {NULL, 0, NULL, 0, NULL}
 222 };
 223 #endif
 224
 225 algo_type ssh_nocompress[] = {
 226         {"none", DROPBEAR_COMP_NONE, NULL, 1, NULL},
 227         {NULL, 0, NULL, 0, NULL}
 228 };
 229
 230 algo_type sshhostkey[] = {
 231 #ifdef DROPBEAR_ECDSA
 232 #ifdef DROPBEAR_ECC_256
 233         {"ecdsa-sha2-nistp256", DROPBEAR_SIGNKEY_ECDSA_NISTP256, NULL, 1, NULL},
 234 #endif
 235 #ifdef DROPBEAR_ECC_384
 236         {"ecdsa-sha2-nistp384", DROPBEAR_SIGNKEY_ECDSA_NISTP384, NULL, 1, NULL},
 237 #endif
 238 #ifdef DROPBEAR_ECC_521
 239         {"ecdsa-sha2-nistp521", DROPBEAR_SIGNKEY_ECDSA_NISTP521, NULL, 1, NULL},
 240 #endif
 241 #endif
 242 #ifdef DROPBEAR_RSA
 243         {"ssh-rsa", DROPBEAR_SIGNKEY_RSA, NULL, 1, NULL},
 244 #endif
 245 #ifdef DROPBEAR_DSS
 246         {"ssh-dss", DROPBEAR_SIGNKEY_DSS, NULL, 1, NULL},
 247 #endif
 248         {NULL, 0, NULL, 0, NULL}
 249 };
 250
 251 static const struct dropbear_kex kex_dh_group1 = {DROPBEAR_KEX_NORMAL_DH, dh_p_1, DH_P_1_LEN, NULL, &sha1_desc };
 252 static const struct dropbear_kex kex_dh_group14 = {DROPBEAR_KEX_NORMAL_DH, dh_p_14, DH_P_14_LEN, NULL, &sha1_desc };
 253
 254 /* These can't be const since dropbear_ecc_fill_dp() fills out
 255  ecc_curve at runtime */
 256 #ifdef DROPBEAR_ECDH
 257 #ifdef DROPBEAR_ECC_256
 258 static struct dropbear_kex kex_ecdh_nistp256 = {DROPBEAR_KEX_ECDH, NULL, 0, &ecc_curve_nistp256, &sha256_desc };
 259 #endif
 260 #ifdef DROPBEAR_ECC_384
 261 static struct dropbear_kex kex_ecdh_nistp384 = {DROPBEAR_KEX_ECDH, NULL, 0, &ecc_curve_nistp384, &sha384_desc };
 262 #endif
 263 #ifdef DROPBEAR_ECC_521
 264 static struct dropbear_kex kex_ecdh_nistp521 = {DROPBEAR_KEX_ECDH, NULL, 0, &ecc_curve_nistp521, &sha512_desc };
 265 #endif
 266 #endif /* DROPBEAR_ECDH */
 267
 268 #ifdef DROPBEAR_CURVE25519
 269 /* Referred to directly */
 270 static const struct dropbear_kex kex_curve25519 = {DROPBEAR_KEX_CURVE25519, NULL, 0, NULL, &sha256_desc };
 271 #endif
 272
 273 algo_type sshkex[] = {
 274 #ifdef DROPBEAR_CURVE25519
 275         {"curve25519-sha256@libssh.org", 0, &kex_curve25519, 1, NULL},
 276 #endif
 277 #ifdef DROPBEAR_ECDH
 278 #ifdef DROPBEAR_ECC_521
 279         {"ecdh-sha2-nistp521", 0, &kex_ecdh_nistp521, 1, NULL},
 280 #endif
 281 #ifdef DROPBEAR_ECC_384
 282         {"ecdh-sha2-nistp384", 0, &kex_ecdh_nistp384, 1, NULL},
 283 #endif
 284 #ifdef DROPBEAR_ECC_256
 285         {"ecdh-sha2-nistp256", 0, &kex_ecdh_nistp256, 1, NULL},
 286 #endif
 287 #endif
 288         {"diffie-hellman-group14-sha1", 0, &kex_dh_group14, 1, NULL},
 289         {"diffie-hellman-group1-sha1", 0, &kex_dh_group1, 1, NULL},
 290 #ifdef USE_KEXGUESS2
 291         {KEXGUESS2_ALGO_NAME, KEXGUESS2_ALGO_ID, NULL, 1, NULL},
 292 #endif
 293         {NULL, 0, NULL, 0, NULL}
 294 };
 295
 296 /* algolen specifies the length of algo, algos is our local list to match
 297  * against.
 298  * Returns DROPBEAR_SUCCESS if we have a match for algo, DROPBEAR_FAILURE
 299  * otherwise */
 300 int have_algo(char* algo, size_t algolen, algo_type algos[]) {
 301
 302         int i;
 303
 304         for (i = 0; algos[i].name != NULL; i++) {
 305                 if (strlen(algos[i].name) == algolen
 306                                 && (strncmp(algos[i].name, algo, algolen) == 0)) {
 307                         return DROPBEAR_SUCCESS;
 308                 }
 309         }
 310
 311         return DROPBEAR_FAILURE;
 312 }
 313
 314 /* Output a comma separated list of algorithms to a buffer */
 315 void buf_put_algolist(buffer * buf, algo_type localalgos[]) {
 316
 317         unsigned int i, len;
 318         unsigned int donefirst = 0;
 319         buffer *algolist = NULL;
 320
 321         algolist = buf_new(200);
 322         for (i = 0; localalgos[i].name != NULL; i++) {
 323                 if (localalgos[i].usable) {
 324                         if (donefirst)
 325                                 buf_putbyte(algolist, ',');
 326                         donefirst = 1;
 327                         len = strlen(localalgos[i].name);
 328                         buf_putbytes(algolist, (const unsigned char *) localalgos[i].name, len);
 329                 }
 330         }
 331         buf_putstring(buf, (const char*)algolist->data, algolist->len);
 332         buf_free(algolist);
 333 }
 334
 335 /* match the first algorithm in the comma-separated list in buf which is
 336  * also in localalgos[], or return NULL on failure.
 337  * (*goodguess) is set to 1 if the preferred client/server algos match,
 338  * 0 otherwise. This is used for checking if the kexalgo/hostkeyalgos are
 339  * guessed correctly */
 340 algo_type * buf_match_algo(buffer* buf, algo_type localalgos[],
 341                 enum kexguess2_used *kexguess2, int *goodguess)
 342 {
 343
 344         char * algolist = NULL;
 345         const char *remotenames[MAX_PROPOSED_ALGO], *localnames[MAX_PROPOSED_ALGO];
 346         unsigned int len;
 347         unsigned int remotecount, localcount, clicount, servcount, i, j;
 348         algo_type * ret = NULL;
 349         const char **clinames, **servnames;
 350
 351         if (goodguess) {
 352                 *goodguess = 0;
 353         }
 354
 355         /* get the comma-separated list from the buffer ie "algo1,algo2,algo3" */
 356         algolist = buf_getstring(buf, &len);
 357         TRACE(("buf_match_algo: %s", algolist))
 358         if (len > MAX_PROPOSED_ALGO*(MAX_NAME_LEN+1)) {
 359                 goto out;
 360         }
 361
 362         /* remotenames will contain a list of the strings parsed out */
 363         /* We will have at least one string (even if it's just "") */
 364         remotenames[0] = algolist;
 365         remotecount = 1;
 366         for (i = 0; i < len; i++) {
 367                 if (algolist[i] == '\0') {
 368                         /* someone is trying something strange */
 369                         goto out;
 370                 }
 371                 if (algolist[i] == ',') {
 372                         algolist[i] = '\0';
 373                         remotenames[remotecount] = &algolist[i+1];
 374                         remotecount++;
 375                 }
 376                 if (remotecount >= MAX_PROPOSED_ALGO) {
 377                         break;
 378                 }
 379         }
 380         if (kexguess2 && *kexguess2 == KEXGUESS2_LOOK) {
 381                 for (i = 0; i < remotecount; i++)
 382                 {
 383                         if (strcmp(remotenames[i], KEXGUESS2_ALGO_NAME) == 0) {
 384                                 *kexguess2 = KEXGUESS2_YES;
 385                                 break;
 386                         }
 387                 }
 388                 if (*kexguess2 == KEXGUESS2_LOOK) {
 389                         *kexguess2 = KEXGUESS2_NO;
 390                 }
 391         }
 392
 393         for (i = 0; localalgos[i].name != NULL; i++) {
 394                 if (localalgos[i].usable) {
 395                         localnames[i] = localalgos[i].name;
 396                 } else {
 397                         localnames[i] = NULL;
 398                 }
 399         }
 400         localcount = i;
 401
 402         if (IS_DROPBEAR_SERVER) {
 403                 clinames = remotenames;
 404                 clicount = remotecount;
 405                 servnames = localnames;
 406                 servcount = localcount;
 407         } else {
 408                 clinames = localnames;
 409                 clicount = localcount;
 410                 servnames = remotenames;
 411                 servcount = remotecount;
 412         }
 413
 414         /* iterate and find the first match */
 415         for (i = 0; i < clicount; i++) {
 416                 for (j = 0; j < servcount; j++) {
 417                         if (!(servnames[j] && clinames[i])) {
 418                                 /* unusable algos are NULL */
 419                                 continue;
 420                         }
 421                         if (strcmp(servnames[j], clinames[i]) == 0) {
 422                                 /* set if it was a good guess */
 423                                 if (goodguess && kexguess2) {
 424                                         if (*kexguess2 == KEXGUESS2_YES) {
 425                                                 if (i == 0) {
 426                                                         *goodguess = 1;
 427                                                 }
 428
 429                                         } else {
 430                                                 if (i == 0 && j == 0) {
 431                                                         *goodguess = 1;
 432                                                 }
 433                                         }
 434                                 }
 435                                 /* set the algo to return */
 436                                 if (IS_DROPBEAR_SERVER) {
 437                                         ret = &localalgos[j];
 438                                 } else {
 439                                         ret = &localalgos[i];
 440                                 }
 441                                 goto out;
 442                         }
 443                 }
 444         }
 445
 446 out:
 447         m_free(algolist);
 448         return ret;
 449 }
 450
 451 #ifdef DROPBEAR_NONE_CIPHER
 452
 453 void
 454 set_algo_usable(algo_type algos[], const char * algo_name, int usable)
 455 {
 456         algo_type *a;
 457         for (a = algos; a->name != NULL; a++)
 458         {
 459                 if (strcmp(a->name, algo_name) == 0)
 460                 {
 461                         a->usable = usable;
 462                         return;
 463                 }
 464         }
 465 }
 466
 467 int
 468 get_algo_usable(algo_type algos[], const char * algo_name)
 469 {
 470         algo_type *a;
 471         for (a = algos; a->name != NULL; a++)
 472         {
 473                 if (strcmp(a->name, algo_name) == 0)
 474                 {
 475                         return a->usable;
 476                 }
 477         }
 478         return 0;
 479 }
 480
 481 #endif /* DROPBEAR_NONE_CIPHER */
 482
 483 #ifdef ENABLE_USER_ALGO_LIST
 484
 485 char *
 486 algolist_string(algo_type algos[])
 487 {
 488         char *ret_list;
 489         buffer *b = buf_new(200);
 490         buf_put_algolist(b, algos);
 491         buf_setpos(b, b->len);
 492         buf_putbyte(b, '\0');
 493         buf_setpos(b, 4);
 494         ret_list = m_strdup((const char *) buf_getptr(b, b->len - b->pos));
 495         buf_free(b);
 496         return ret_list;
 497 }
 498
 499 static algo_type*
 500 check_algo(const char* algo_name, algo_type *algos)
 501 {
 502         algo_type *a;
 503         for (a = algos; a->name != NULL; a++)
 504         {
 505                 if (strcmp(a->name, algo_name) == 0)
 506                 {
 507                         return a;
 508                 }
 509         }
 510
 511         return NULL;
 512 }
 513
 514 static void
 515 try_add_algo(const char *algo_name, algo_type *algos,
 516                 const char *algo_desc, algo_type * new_algos, int *num_ret)
 517 {
 518         algo_type *match_algo = check_algo(algo_name, algos);
 519         if (!match_algo)
 520         {
 521                 dropbear_log(LOG_WARNING, "This Dropbear program does not support '%s' %s algorithm", algo_name, algo_desc);
 522                 return;
 523         }
 524
 525         new_algos[*num_ret] = *match_algo;
 526         (*num_ret)++;
 527 }
 528
 529 /* Checks a user provided comma-separated algorithm list for available
 530  * options. Any that are not acceptable are removed in-place. Returns the
 531  * number of valid algorithms. */
 532 int
 533 check_user_algos(const char* user_algo_list, algo_type * algos,
 534                 const char *algo_desc)
 535 {
 536         algo_type new_algos[MAX_PROPOSED_ALGO];
 537         /* this has two passes. first we sweep through the given list of
 538          * algorithms and mark them as usable=2 in the algo_type[] array... */
 539         int num_ret = 0;
 540         char *work_list = m_strdup(user_algo_list);
 541         char *last_name = work_list;
 542         char *c;
 543         for (c = work_list; *c; c++)
 544         {
 545                 if (*c == ',')
 546                 {
 547                         *c = '\0';
 548                         try_add_algo(last_name, algos, algo_desc, new_algos, &num_ret);
 549                         c++;
 550                         last_name = c;
 551                 }
 552         }
 553         try_add_algo(last_name, algos, algo_desc, new_algos, &num_ret);
 554         m_free(work_list);
 555
 556         new_algos[num_ret].name = NULL;
 557
 558         /* Copy one more as a blank delimiter */
 559         memcpy(algos, new_algos, sizeof(*new_algos) * (num_ret+1));
 560         return num_ret;
 561 }
 562 #endif /* ENABLE_USER_ALGO_LIST */