cipher.c revision 1.5.4.1
1/* $NetBSD: cipher.c,v 1.5.4.1 2015/04/30 06:07:30 riz Exp $ */ 2/* $OpenBSD: cipher.c,v 1.100 2015/01/14 10:29:45 djm Exp $ */ 3/* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * 15 * Copyright (c) 1999 Niels Provos. All rights reserved. 16 * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39#include "includes.h" 40__RCSID("$NetBSD: cipher.c,v 1.5.4.1 2015/04/30 06:07:30 riz Exp $"); 41#include <sys/types.h> 42 43#include <string.h> 44#include <stdarg.h> 45#include <stdio.h> 46 47#include "cipher.h" 48#include "misc.h" 49#include "sshbuf.h" 50#include "ssherr.h" 51#include "digest.h" 52 53#ifdef WITH_SSH1 54extern const EVP_CIPHER *evp_ssh1_bf(void); 55extern const EVP_CIPHER *evp_ssh1_3des(void); 56extern int ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int); 57#endif 58 59struct sshcipher { 60 const char *name; 61 int number; /* for ssh1 only */ 62 u_int block_size; 63 u_int key_len; 64 u_int iv_len; /* defaults to block_size */ 65 u_int auth_len; 66 u_int discard_len; 67 u_int flags; 68#define CFLAG_CBC (1<<0) 69#define CFLAG_CHACHAPOLY (1<<1) 70#define CFLAG_AESCTR (1<<2) 71#define CFLAG_NONE (1<<3) 72#ifdef WITH_OPENSSL 73 const EVP_CIPHER *(*evptype)(void); 74#else 75 void *ignored; 76#endif 77}; 78 79static const struct sshcipher ciphers[] = { 80#ifdef WITH_SSH1 81 { "des", SSH_CIPHER_DES, 8, 8, 0, 0, 0, 1, EVP_des_cbc }, 82 { "3des", SSH_CIPHER_3DES, 8, 16, 0, 0, 0, 1, evp_ssh1_3des }, 83 { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, 0, 0, 0, 1, evp_ssh1_bf }, 84#endif 85#ifdef WITH_OPENSSL 86 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, 0, EVP_enc_null }, 87 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, 0, 0, 0, 1, EVP_des_ede3_cbc }, 88 { "blowfish-cbc", 89 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_bf_cbc }, 90 { "cast128-cbc", 91 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_cast5_cbc }, 92 { "arcfour", SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 0, EVP_rc4 }, 93 { "arcfour128", SSH_CIPHER_SSH2, 8, 16, 0, 0, 1536, 0, EVP_rc4 }, 94 { "arcfour256", SSH_CIPHER_SSH2, 8, 32, 0, 0, 1536, 0, EVP_rc4 }, 95 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 1, EVP_aes_128_cbc }, 96 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 1, EVP_aes_192_cbc }, 97 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc }, 98 { "rijndael-cbc@lysator.liu.se", 99 SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc }, 100#ifdef AES_CTR_MT 101 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 0, evp_aes_ctr_mt }, 102 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 0, evp_aes_ctr_mt }, 103 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 0, evp_aes_ctr_mt }, 104#else 105 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 0, EVP_aes_128_ctr }, 106 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 0, EVP_aes_192_ctr }, 107 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 0, EVP_aes_256_ctr }, 108#endif 109 { "aes128-gcm@openssh.com", 110 SSH_CIPHER_SSH2, 16, 16, 12, 16, 0, 0, EVP_aes_128_gcm }, 111 { "aes256-gcm@openssh.com", 112 SSH_CIPHER_SSH2, 16, 32, 12, 16, 0, 0, EVP_aes_256_gcm }, 113#else 114 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, CFLAG_AESCTR, NULL }, 115 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, CFLAG_AESCTR, NULL }, 116 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, CFLAG_AESCTR, NULL }, 117 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, CFLAG_NONE, NULL }, 118#endif 119 { "chacha20-poly1305@openssh.com", 120 SSH_CIPHER_SSH2, 8, 64, 0, 16, 0, CFLAG_CHACHAPOLY, NULL }, 121 122 { NULL, SSH_CIPHER_INVALID, 0, 0, 0, 0, 0, 0, NULL } 123}; 124 125/*--*/ 126 127/* Returns a comma-separated list of supported ciphers. */ 128char * 129cipher_alg_list(char sep, int auth_only) 130{ 131 char *tmp, *ret = NULL; 132 size_t nlen, rlen = 0; 133 const struct sshcipher *c; 134 135 for (c = ciphers; c->name != NULL; c++) { 136 if (c->number != SSH_CIPHER_SSH2) 137 continue; 138 if (auth_only && c->auth_len == 0) 139 continue; 140 if (ret != NULL) 141 ret[rlen++] = sep; 142 nlen = strlen(c->name); 143 if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) { 144 free(ret); 145 return NULL; 146 } 147 ret = tmp; 148 memcpy(ret + rlen, c->name, nlen + 1); 149 rlen += nlen; 150 } 151 return ret; 152} 153 154u_int 155cipher_blocksize(const struct sshcipher *c) 156{ 157 return (c->block_size); 158} 159 160u_int 161cipher_keylen(const struct sshcipher *c) 162{ 163 return (c->key_len); 164} 165 166u_int 167cipher_seclen(const struct sshcipher *c) 168{ 169 if (strcmp("3des-cbc", c->name) == 0) 170 return 14; 171 return cipher_keylen(c); 172} 173 174u_int 175cipher_authlen(const struct sshcipher *c) 176{ 177 return (c->auth_len); 178} 179 180u_int 181cipher_ivlen(const struct sshcipher *c) 182{ 183 /* 184 * Default is cipher block size, except for chacha20+poly1305 that 185 * needs no IV. XXX make iv_len == -1 default? 186 */ 187 return (c->iv_len != 0 || (c->flags & CFLAG_CHACHAPOLY) != 0) ? 188 c->iv_len : c->block_size; 189} 190 191u_int 192cipher_get_number(const struct sshcipher *c) 193{ 194 return (c->number); 195} 196 197u_int 198cipher_is_cbc(const struct sshcipher *c) 199{ 200 return (c->flags & CFLAG_CBC) != 0; 201} 202 203u_int 204cipher_mask_ssh1(int client) 205{ 206 u_int mask = 0; 207 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */ 208 mask |= 1 << SSH_CIPHER_BLOWFISH; 209 if (client) { 210 mask |= 1 << SSH_CIPHER_DES; 211 } 212 return mask; 213} 214 215const struct sshcipher * 216cipher_by_name(const char *name) 217{ 218 const struct sshcipher *c; 219 for (c = ciphers; c->name != NULL; c++) 220 if (strcmp(c->name, name) == 0) 221 return c; 222 return NULL; 223} 224 225const struct sshcipher * 226cipher_by_number(int id) 227{ 228 const struct sshcipher *c; 229 for (c = ciphers; c->name != NULL; c++) 230 if (c->number == id) 231 return c; 232 return NULL; 233} 234 235#define CIPHER_SEP "," 236int 237ciphers_valid(const char *names) 238{ 239 const struct sshcipher *c; 240 char *cipher_list, *cp; 241 char *p; 242 243 if (names == NULL || strcmp(names, "") == 0) 244 return 0; 245 if ((cipher_list = cp = strdup(names)) == NULL) 246 return 0; 247 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0'; 248 (p = strsep(&cp, CIPHER_SEP))) { 249 c = cipher_by_name(p); 250 if (c == NULL || (c->number != SSH_CIPHER_SSH2 && 251c->number != SSH_CIPHER_NONE)) { 252 free(cipher_list); 253 return 0; 254 } 255 } 256 free(cipher_list); 257 return 1; 258} 259 260/* 261 * Parses the name of the cipher. Returns the number of the corresponding 262 * cipher, or -1 on error. 263 */ 264 265int 266cipher_number(const char *name) 267{ 268 const struct sshcipher *c; 269 if (name == NULL) 270 return -1; 271 for (c = ciphers; c->name != NULL; c++) 272 if (strcasecmp(c->name, name) == 0) 273 return c->number; 274 return -1; 275} 276 277const char * 278cipher_name(int id) 279{ 280 const struct sshcipher *c = cipher_by_number(id); 281 return (c==NULL) ? "<unknown>" : c->name; 282} 283 284const char * 285cipher_warning_message(const struct sshcipher_ctx *cc) 286{ 287 if (cc == NULL || cc->cipher == NULL) 288 return NULL; 289 if (cc->cipher->number == SSH_CIPHER_DES) 290 return "use of DES is strongly discouraged due to " 291 "cryptographic weaknesses"; 292 return NULL; 293} 294 295int 296cipher_init(struct sshcipher_ctx *cc, const struct sshcipher *cipher, 297 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen, 298 int do_encrypt) 299{ 300#ifdef WITH_OPENSSL 301 int ret = SSH_ERR_INTERNAL_ERROR; 302 const EVP_CIPHER *type; 303 int klen; 304 u_char *junk, *discard; 305 306 if (cipher->number == SSH_CIPHER_DES) { 307 if (keylen > 8) 308 keylen = 8; 309 } 310#endif 311 cc->plaintext = (cipher->number == SSH_CIPHER_NONE); 312 cc->encrypt = do_encrypt; 313 314 if (keylen < cipher->key_len || 315 (iv != NULL && ivlen < cipher_ivlen(cipher))) 316 return SSH_ERR_INVALID_ARGUMENT; 317 318 cc->cipher = cipher; 319 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) { 320 return chachapoly_init(&cc->cp_ctx, key, keylen); 321 } 322#ifndef WITH_OPENSSL 323 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) { 324 aesctr_keysetup(&cc->ac_ctx, key, 8 * keylen, 8 * ivlen); 325 aesctr_ivsetup(&cc->ac_ctx, iv); 326 return 0; 327 } 328 if ((cc->cipher->flags & CFLAG_NONE) != 0) 329 return 0; 330 return SSH_ERR_INVALID_ARGUMENT; 331#else 332 type = (*cipher->evptype)(); 333 EVP_CIPHER_CTX_init(&cc->evp); 334 if (EVP_CipherInit(&cc->evp, type, NULL, __UNCONST(iv), 335 (do_encrypt == CIPHER_ENCRYPT)) == 0) { 336 ret = SSH_ERR_LIBCRYPTO_ERROR; 337 goto bad; 338 } 339 if (cipher_authlen(cipher) && 340 !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_SET_IV_FIXED, 341 -1, __UNCONST(iv))) { 342 ret = SSH_ERR_LIBCRYPTO_ERROR; 343 goto bad; 344 } 345 klen = EVP_CIPHER_CTX_key_length(&cc->evp); 346 if (klen > 0 && keylen != (u_int)klen) { 347 if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0) { 348 ret = SSH_ERR_LIBCRYPTO_ERROR; 349 goto bad; 350 } 351 } 352 if (EVP_CipherInit(&cc->evp, NULL, __UNCONST(key), NULL, -1) == 0) { 353 ret = SSH_ERR_LIBCRYPTO_ERROR; 354 goto bad; 355 } 356 357 if (cipher->discard_len > 0) { 358 if ((junk = malloc(cipher->discard_len)) == NULL || 359 (discard = malloc(cipher->discard_len)) == NULL) { 360 if (junk != NULL) 361 free(junk); 362 ret = SSH_ERR_ALLOC_FAIL; 363 goto bad; 364 } 365 ret = EVP_Cipher(&cc->evp, discard, junk, cipher->discard_len); 366 explicit_bzero(discard, cipher->discard_len); 367 free(junk); 368 free(discard); 369 if (ret != 1) { 370 ret = SSH_ERR_LIBCRYPTO_ERROR; 371 bad: 372 EVP_CIPHER_CTX_cleanup(&cc->evp); 373 return ret; 374 } 375 } 376#endif 377 return 0; 378} 379 380/* 381 * cipher_crypt() operates as following: 382 * Copy 'aadlen' bytes (without en/decryption) from 'src' to 'dest'. 383 * Theses bytes are treated as additional authenticated data for 384 * authenticated encryption modes. 385 * En/Decrypt 'len' bytes at offset 'aadlen' from 'src' to 'dest'. 386 * Use 'authlen' bytes at offset 'len'+'aadlen' as the authentication tag. 387 * This tag is written on encryption and verified on decryption. 388 * Both 'aadlen' and 'authlen' can be set to 0. 389 */ 390int 391cipher_crypt(struct sshcipher_ctx *cc, u_int seqnr, u_char *dest, 392 const u_char *src, u_int len, u_int aadlen, u_int authlen) 393{ 394 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) { 395 return chachapoly_crypt(&cc->cp_ctx, seqnr, dest, src, 396 len, aadlen, authlen, cc->encrypt); 397 } 398#ifndef WITH_OPENSSL 399 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) { 400 if (aadlen) 401 memcpy(dest, src, aadlen); 402 aesctr_encrypt_bytes(&cc->ac_ctx, src + aadlen, 403 dest + aadlen, len); 404 return 0; 405 } 406 if ((cc->cipher->flags & CFLAG_NONE) != 0) { 407 memcpy(dest, src, aadlen + len); 408 return 0; 409 } 410 return SSH_ERR_INVALID_ARGUMENT; 411#else 412 if (authlen) { 413 u_char lastiv[1]; 414 415 if (authlen != cipher_authlen(cc->cipher)) 416 return SSH_ERR_INVALID_ARGUMENT; 417 /* increment IV */ 418 if (!EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_IV_GEN, 419 1, lastiv)) 420 return SSH_ERR_LIBCRYPTO_ERROR; 421 /* set tag on decyption */ 422 if (!cc->encrypt && 423 !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_SET_TAG, 424 authlen, __UNCONST(src + aadlen + len))) 425 return SSH_ERR_LIBCRYPTO_ERROR; 426 } 427 if (aadlen) { 428 if (authlen && 429 EVP_Cipher(&cc->evp, NULL, (const u_char *)src, aadlen) < 0) 430 return SSH_ERR_LIBCRYPTO_ERROR; 431 memcpy(dest, src, aadlen); 432 } 433 if (len % cc->cipher->block_size) 434 return SSH_ERR_INVALID_ARGUMENT; 435 if (EVP_Cipher(&cc->evp, dest + aadlen, (const u_char *)src + aadlen, 436 len) < 0) 437 return SSH_ERR_LIBCRYPTO_ERROR; 438 if (authlen) { 439 /* compute tag (on encrypt) or verify tag (on decrypt) */ 440 if (EVP_Cipher(&cc->evp, NULL, NULL, 0) < 0) 441 return cc->encrypt ? 442 SSH_ERR_LIBCRYPTO_ERROR : SSH_ERR_MAC_INVALID; 443 if (cc->encrypt && 444 !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_GET_TAG, 445 authlen, dest + aadlen + len)) 446 return SSH_ERR_LIBCRYPTO_ERROR; 447 } 448 return 0; 449#endif 450} 451 452/* Extract the packet length, including any decryption necessary beforehand */ 453int 454cipher_get_length(struct sshcipher_ctx *cc, u_int *plenp, u_int seqnr, 455 const u_char *cp, u_int len) 456{ 457 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 458 return chachapoly_get_length(&cc->cp_ctx, plenp, seqnr, 459 cp, len); 460 if (len < 4) 461 return SSH_ERR_MESSAGE_INCOMPLETE; 462 *plenp = get_u32(cp); 463 return 0; 464} 465 466int 467cipher_cleanup(struct sshcipher_ctx *cc) 468{ 469 if (cc == NULL || cc->cipher == NULL) 470 return 0; 471 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 472 explicit_bzero(&cc->cp_ctx, sizeof(cc->cp_ctx)); 473 else if ((cc->cipher->flags & CFLAG_AESCTR) != 0) 474 explicit_bzero(&cc->ac_ctx, sizeof(cc->ac_ctx)); 475#ifdef WITH_OPENSSL 476 else if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0) 477 return SSH_ERR_LIBCRYPTO_ERROR; 478#endif 479 return 0; 480} 481 482/* 483 * Selects the cipher, and keys if by computing the MD5 checksum of the 484 * passphrase and using the resulting 16 bytes as the key. 485 */ 486int 487cipher_set_key_string(struct sshcipher_ctx *cc, const struct sshcipher *cipher, 488 const char *passphrase, int do_encrypt) 489{ 490 u_char digest[16]; 491 int r = SSH_ERR_INTERNAL_ERROR; 492 493 if ((r = ssh_digest_memory(SSH_DIGEST_MD5, 494 passphrase, strlen(passphrase), 495 digest, sizeof(digest))) != 0) 496 goto out; 497 498 r = cipher_init(cc, cipher, digest, 16, NULL, 0, do_encrypt); 499 out: 500 explicit_bzero(digest, sizeof(digest)); 501 return r; 502} 503 504/* 505 * Exports an IV from the sshcipher_ctx required to export the key 506 * state back from the unprivileged child to the privileged parent 507 * process. 508 */ 509int 510cipher_get_keyiv_len(const struct sshcipher_ctx *cc) 511{ 512 const struct sshcipher *c = cc->cipher; 513 int ivlen = 0; 514 515 if (c->number == SSH_CIPHER_3DES) 516 ivlen = 24; 517 else if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 518 ivlen = 0; 519 else if ((cc->cipher->flags & CFLAG_AESCTR) != 0) 520 ivlen = sizeof(cc->ac_ctx.ctr); 521#ifdef WITH_OPENSSL 522 else 523 ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp); 524#endif /* WITH_OPENSSL */ 525 return (ivlen); 526} 527 528int 529cipher_get_keyiv(struct sshcipher_ctx *cc, u_char *iv, u_int len) 530{ 531 const struct sshcipher *c = cc->cipher; 532#ifdef WITH_OPENSSL 533 int evplen; 534#endif 535 536 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) { 537 if (len != 0) 538 return SSH_ERR_INVALID_ARGUMENT; 539 return 0; 540 } 541 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) { 542 if (len != sizeof(cc->ac_ctx.ctr)) 543 return SSH_ERR_INVALID_ARGUMENT; 544 memcpy(iv, cc->ac_ctx.ctr, len); 545 return 0; 546 } 547 if ((cc->cipher->flags & CFLAG_NONE) != 0) 548 return 0; 549 550 switch (c->number) { 551#ifdef WITH_OPENSSL 552 case SSH_CIPHER_NONE: 553 case SSH_CIPHER_SSH2: 554 case SSH_CIPHER_DES: 555 case SSH_CIPHER_BLOWFISH: 556 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp); 557 if (evplen == 0) 558 return 0; 559 else if (evplen < 0) 560 return SSH_ERR_LIBCRYPTO_ERROR; 561 if ((u_int)evplen != len) 562 return SSH_ERR_INVALID_ARGUMENT; 563 if (cipher_authlen(c)) { 564 if (!EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_IV_GEN, 565 len, iv)) 566 return SSH_ERR_LIBCRYPTO_ERROR; 567 } else 568 memcpy(iv, cc->evp.iv, len); 569 break; 570#endif 571#ifdef WITH_SSH1 572 case SSH_CIPHER_3DES: 573 return ssh1_3des_iv(&cc->evp, 0, iv, 24); 574#endif 575 default: 576 return SSH_ERR_INVALID_ARGUMENT; 577 } 578 return 0; 579} 580 581int 582cipher_set_keyiv(struct sshcipher_ctx *cc, const u_char *iv) 583{ 584 const struct sshcipher *c = cc->cipher; 585#ifdef WITH_OPENSSL 586 int evplen = 0; 587#endif 588 589 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 590 return 0; 591 if ((cc->cipher->flags & CFLAG_NONE) != 0) 592 return 0; 593 594 switch (c->number) { 595#ifdef WITH_OPENSSL 596 case SSH_CIPHER_NONE: 597 case SSH_CIPHER_SSH2: 598 case SSH_CIPHER_DES: 599 case SSH_CIPHER_BLOWFISH: 600 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp); 601 if (evplen <= 0) 602 return SSH_ERR_LIBCRYPTO_ERROR; 603 if (cipher_authlen(c)) { 604 /* XXX iv arg is const, but EVP_CIPHER_CTX_ctrl isn't */ 605 if (!EVP_CIPHER_CTX_ctrl(&cc->evp, 606 EVP_CTRL_GCM_SET_IV_FIXED, -1, __UNCONST(iv))) 607 return SSH_ERR_LIBCRYPTO_ERROR; 608 } else 609 memcpy(cc->evp.iv, iv, evplen); 610 break; 611#endif 612#ifdef WITH_SSH1 613 case SSH_CIPHER_3DES: 614 return ssh1_3des_iv(&cc->evp, 1, __UNCONST(iv), 24); 615#endif 616 default: 617 return SSH_ERR_INVALID_ARGUMENT; 618 } 619 return 0; 620} 621 622#ifdef WITH_OPENSSL 623#define EVP_X_STATE(evp) (evp).cipher_data 624#define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size 625#endif 626 627int 628cipher_get_keycontext(const struct sshcipher_ctx *cc, u_char *dat) 629{ 630#ifdef WITH_OPENSSL 631 const struct sshcipher *c = cc->cipher; 632 int plen = 0; 633 634 if (c->evptype == EVP_rc4) { 635 plen = EVP_X_STATE_LEN(cc->evp); 636 if (dat == NULL) 637 return (plen); 638 memcpy(dat, EVP_X_STATE(cc->evp), plen); 639 } 640 return (plen); 641#else 642 return 0; 643#endif 644} 645 646void 647cipher_set_keycontext(struct sshcipher_ctx *cc, const u_char *dat) 648{ 649#ifdef WITH_OPENSSL 650 const struct sshcipher *c = cc->cipher; 651 int plen; 652 653 if (c->evptype == EVP_rc4) { 654 plen = EVP_X_STATE_LEN(cc->evp); 655 memcpy(EVP_X_STATE(cc->evp), dat, plen); 656 } 657#endif 658} 659