1 /* $OpenBSD: cipher.c,v 1.101 2015/12/10 17:08:40 mmcc Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * 7 * As far as I am concerned, the code I have written for this software 8 * can be used freely for any purpose. Any derived versions of this 9 * software must be clearly marked as such, and if the derived work is 10 * incompatible with the protocol description in the RFC file, it must be 11 * called by a name other than "ssh" or "Secure Shell". 12 * 13 * 14 * Copyright (c) 1999 Niels Provos. All rights reserved. 15 * Copyright (c) 1999, 2000 Markus Friedl. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #include "includes.h" 39 40 #include <sys/types.h> 41 42 #include <string.h> 43 #include <stdarg.h> 44 #include <stdio.h> 45 46 #include "cipher.h" 47 #include "misc.h" 48 #include "sshbuf.h" 49 #include "ssherr.h" 50 #include "digest.h" 51 52 #include "openbsd-compat/openssl-compat.h" 53 54 #ifdef WITH_SSH1 55 extern const EVP_CIPHER *evp_ssh1_bf(void); 56 extern const EVP_CIPHER *evp_ssh1_3des(void); 57 extern int ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int); 58 #endif 59 60 struct sshcipher { 61 char *name; 62 int number; /* for ssh1 only */ 63 u_int block_size; 64 u_int key_len; 65 u_int iv_len; /* defaults to block_size */ 66 u_int auth_len; 67 u_int discard_len; 68 u_int flags; 69 #define CFLAG_CBC (1<<0) 70 #define CFLAG_CHACHAPOLY (1<<1) 71 #define CFLAG_AESCTR (1<<2) 72 #define CFLAG_NONE (1<<3) 73 #ifdef WITH_OPENSSL 74 const EVP_CIPHER *(*evptype)(void); 75 #else 76 void *ignored; 77 #endif 78 }; 79 80 static const struct sshcipher ciphers[] = { 81 #ifdef WITH_SSH1 82 { "des", SSH_CIPHER_DES, 8, 8, 0, 0, 0, 1, EVP_des_cbc }, 83 { "3des", SSH_CIPHER_3DES, 8, 16, 0, 0, 0, 1, evp_ssh1_3des }, 84 { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, 0, 0, 0, 1, evp_ssh1_bf }, 85 #endif /* WITH_SSH1 */ 86 #ifdef WITH_OPENSSL 87 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, 0, EVP_enc_null }, 88 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, 0, 0, 0, 1, EVP_des_ede3_cbc }, 89 { "blowfish-cbc", 90 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_bf_cbc }, 91 { "cast128-cbc", 92 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_cast5_cbc }, 93 { "arcfour", SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 0, EVP_rc4 }, 94 { "arcfour128", SSH_CIPHER_SSH2, 8, 16, 0, 0, 1536, 0, EVP_rc4 }, 95 { "arcfour256", SSH_CIPHER_SSH2, 8, 32, 0, 0, 1536, 0, EVP_rc4 }, 96 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 1, EVP_aes_128_cbc }, 97 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 1, EVP_aes_192_cbc }, 98 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc }, 99 { "rijndael-cbc@lysator.liu.se", 100 SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc }, 101 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 0, EVP_aes_128_ctr }, 102 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 0, EVP_aes_192_ctr }, 103 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 0, EVP_aes_256_ctr }, 104 # ifdef OPENSSL_HAVE_EVPGCM 105 { "aes128-gcm@openssh.com", 106 SSH_CIPHER_SSH2, 16, 16, 12, 16, 0, 0, EVP_aes_128_gcm }, 107 { "aes256-gcm@openssh.com", 108 SSH_CIPHER_SSH2, 16, 32, 12, 16, 0, 0, EVP_aes_256_gcm }, 109 # endif /* OPENSSL_HAVE_EVPGCM */ 110 #else /* WITH_OPENSSL */ 111 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, CFLAG_AESCTR, NULL }, 112 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, CFLAG_AESCTR, NULL }, 113 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, CFLAG_AESCTR, NULL }, 114 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, CFLAG_NONE, NULL }, 115 #endif /* WITH_OPENSSL */ 116 { "chacha20-poly1305@openssh.com", 117 SSH_CIPHER_SSH2, 8, 64, 0, 16, 0, CFLAG_CHACHAPOLY, NULL }, 118 119 { NULL, SSH_CIPHER_INVALID, 0, 0, 0, 0, 0, 0, NULL } 120 }; 121 122 /*--*/ 123 124 /* Returns a comma-separated list of supported ciphers. */ 125 char * 126 cipher_alg_list(char sep, int auth_only) 127 { 128 char *tmp, *ret = NULL; 129 size_t nlen, rlen = 0; 130 const struct sshcipher *c; 131 132 for (c = ciphers; c->name != NULL; c++) { 133 if (c->number != SSH_CIPHER_SSH2) 134 continue; 135 if (auth_only && c->auth_len == 0) 136 continue; 137 if (ret != NULL) 138 ret[rlen++] = sep; 139 nlen = strlen(c->name); 140 if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) { 141 free(ret); 142 return NULL; 143 } 144 ret = tmp; 145 memcpy(ret + rlen, c->name, nlen + 1); 146 rlen += nlen; 147 } 148 return ret; 149 } 150 151 u_int 152 cipher_blocksize(const struct sshcipher *c) 153 { 154 return (c->block_size); 155 } 156 157 u_int 158 cipher_keylen(const struct sshcipher *c) 159 { 160 return (c->key_len); 161 } 162 163 u_int 164 cipher_seclen(const struct sshcipher *c) 165 { 166 if (strcmp("3des-cbc", c->name) == 0) 167 return 14; 168 return cipher_keylen(c); 169 } 170 171 u_int 172 cipher_authlen(const struct sshcipher *c) 173 { 174 return (c->auth_len); 175 } 176 177 u_int 178 cipher_ivlen(const struct sshcipher *c) 179 { 180 /* 181 * Default is cipher block size, except for chacha20+poly1305 that 182 * needs no IV. XXX make iv_len == -1 default? 183 */ 184 return (c->iv_len != 0 || (c->flags & CFLAG_CHACHAPOLY) != 0) ? 185 c->iv_len : c->block_size; 186 } 187 188 u_int 189 cipher_get_number(const struct sshcipher *c) 190 { 191 return (c->number); 192 } 193 194 u_int 195 cipher_is_cbc(const struct sshcipher *c) 196 { 197 return (c->flags & CFLAG_CBC) != 0; 198 } 199 200 u_int 201 cipher_mask_ssh1(int client) 202 { 203 u_int mask = 0; 204 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */ 205 mask |= 1 << SSH_CIPHER_BLOWFISH; 206 if (client) { 207 mask |= 1 << SSH_CIPHER_DES; 208 } 209 return mask; 210 } 211 212 const struct sshcipher * 213 cipher_by_name(const char *name) 214 { 215 const struct sshcipher *c; 216 for (c = ciphers; c->name != NULL; c++) 217 if (strcmp(c->name, name) == 0) 218 return c; 219 return NULL; 220 } 221 222 const struct sshcipher * 223 cipher_by_number(int id) 224 { 225 const struct sshcipher *c; 226 for (c = ciphers; c->name != NULL; c++) 227 if (c->number == id) 228 return c; 229 return NULL; 230 } 231 232 #define CIPHER_SEP "," 233 int 234 ciphers_valid(const char *names) 235 { 236 const struct sshcipher *c; 237 char *cipher_list, *cp; 238 char *p; 239 240 if (names == NULL || strcmp(names, "") == 0) 241 return 0; 242 if ((cipher_list = cp = strdup(names)) == NULL) 243 return 0; 244 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0'; 245 (p = strsep(&cp, CIPHER_SEP))) { 246 c = cipher_by_name(p); 247 if (c == NULL || c->number != SSH_CIPHER_SSH2) { 248 free(cipher_list); 249 return 0; 250 } 251 } 252 free(cipher_list); 253 return 1; 254 } 255 256 /* 257 * Parses the name of the cipher. Returns the number of the corresponding 258 * cipher, or -1 on error. 259 */ 260 261 int 262 cipher_number(const char *name) 263 { 264 const struct sshcipher *c; 265 if (name == NULL) 266 return -1; 267 for (c = ciphers; c->name != NULL; c++) 268 if (strcasecmp(c->name, name) == 0) 269 return c->number; 270 return -1; 271 } 272 273 char * 274 cipher_name(int id) 275 { 276 const struct sshcipher *c = cipher_by_number(id); 277 return (c==NULL) ? "<unknown>" : c->name; 278 } 279 280 const char * 281 cipher_warning_message(const struct sshcipher_ctx *cc) 282 { 283 if (cc == NULL || cc->cipher == NULL) 284 return NULL; 285 if (cc->cipher->number == SSH_CIPHER_DES) 286 return "use of DES is strongly discouraged due to " 287 "cryptographic weaknesses"; 288 return NULL; 289 } 290 291 int 292 cipher_init(struct sshcipher_ctx *cc, const struct sshcipher *cipher, 293 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen, 294 int do_encrypt) 295 { 296 #ifdef WITH_OPENSSL 297 int ret = SSH_ERR_INTERNAL_ERROR; 298 const EVP_CIPHER *type; 299 int klen; 300 u_char *junk, *discard; 301 302 if (cipher->number == SSH_CIPHER_DES) { 303 if (keylen > 8) 304 keylen = 8; 305 } 306 #endif 307 cc->plaintext = (cipher->number == SSH_CIPHER_NONE); 308 cc->encrypt = do_encrypt; 309 310 if (keylen < cipher->key_len || 311 (iv != NULL && ivlen < cipher_ivlen(cipher))) 312 return SSH_ERR_INVALID_ARGUMENT; 313 314 cc->cipher = cipher; 315 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) { 316 return chachapoly_init(&cc->cp_ctx, key, keylen); 317 } 318 #ifndef WITH_OPENSSL 319 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) { 320 aesctr_keysetup(&cc->ac_ctx, key, 8 * keylen, 8 * ivlen); 321 aesctr_ivsetup(&cc->ac_ctx, iv); 322 return 0; 323 } 324 if ((cc->cipher->flags & CFLAG_NONE) != 0) 325 return 0; 326 return SSH_ERR_INVALID_ARGUMENT; 327 #else 328 type = (*cipher->evptype)(); 329 EVP_CIPHER_CTX_init(&cc->evp); 330 if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv, 331 (do_encrypt == CIPHER_ENCRYPT)) == 0) { 332 ret = SSH_ERR_LIBCRYPTO_ERROR; 333 goto bad; 334 } 335 if (cipher_authlen(cipher) && 336 !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_SET_IV_FIXED, 337 -1, (u_char *)iv)) { 338 ret = SSH_ERR_LIBCRYPTO_ERROR; 339 goto bad; 340 } 341 klen = EVP_CIPHER_CTX_key_length(&cc->evp); 342 if (klen > 0 && keylen != (u_int)klen) { 343 if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0) { 344 ret = SSH_ERR_LIBCRYPTO_ERROR; 345 goto bad; 346 } 347 } 348 if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0) { 349 ret = SSH_ERR_LIBCRYPTO_ERROR; 350 goto bad; 351 } 352 353 if (cipher->discard_len > 0) { 354 if ((junk = malloc(cipher->discard_len)) == NULL || 355 (discard = malloc(cipher->discard_len)) == NULL) { 356 free(junk); 357 ret = SSH_ERR_ALLOC_FAIL; 358 goto bad; 359 } 360 ret = EVP_Cipher(&cc->evp, discard, junk, cipher->discard_len); 361 explicit_bzero(discard, cipher->discard_len); 362 free(junk); 363 free(discard); 364 if (ret != 1) { 365 ret = SSH_ERR_LIBCRYPTO_ERROR; 366 bad: 367 EVP_CIPHER_CTX_cleanup(&cc->evp); 368 return ret; 369 } 370 } 371 #endif 372 return 0; 373 } 374 375 /* 376 * cipher_crypt() operates as following: 377 * Copy 'aadlen' bytes (without en/decryption) from 'src' to 'dest'. 378 * Theses bytes are treated as additional authenticated data for 379 * authenticated encryption modes. 380 * En/Decrypt 'len' bytes at offset 'aadlen' from 'src' to 'dest'. 381 * Use 'authlen' bytes at offset 'len'+'aadlen' as the authentication tag. 382 * This tag is written on encryption and verified on decryption. 383 * Both 'aadlen' and 'authlen' can be set to 0. 384 */ 385 int 386 cipher_crypt(struct sshcipher_ctx *cc, u_int seqnr, u_char *dest, 387 const u_char *src, u_int len, u_int aadlen, u_int authlen) 388 { 389 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) { 390 return chachapoly_crypt(&cc->cp_ctx, seqnr, dest, src, 391 len, aadlen, authlen, cc->encrypt); 392 } 393 #ifndef WITH_OPENSSL 394 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) { 395 if (aadlen) 396 memcpy(dest, src, aadlen); 397 aesctr_encrypt_bytes(&cc->ac_ctx, src + aadlen, 398 dest + aadlen, len); 399 return 0; 400 } 401 if ((cc->cipher->flags & CFLAG_NONE) != 0) { 402 memcpy(dest, src, aadlen + len); 403 return 0; 404 } 405 return SSH_ERR_INVALID_ARGUMENT; 406 #else 407 if (authlen) { 408 u_char lastiv[1]; 409 410 if (authlen != cipher_authlen(cc->cipher)) 411 return SSH_ERR_INVALID_ARGUMENT; 412 /* increment IV */ 413 if (!EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_IV_GEN, 414 1, lastiv)) 415 return SSH_ERR_LIBCRYPTO_ERROR; 416 /* set tag on decyption */ 417 if (!cc->encrypt && 418 !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_SET_TAG, 419 authlen, (u_char *)src + aadlen + len)) 420 return SSH_ERR_LIBCRYPTO_ERROR; 421 } 422 if (aadlen) { 423 if (authlen && 424 EVP_Cipher(&cc->evp, NULL, (u_char *)src, aadlen) < 0) 425 return SSH_ERR_LIBCRYPTO_ERROR; 426 memcpy(dest, src, aadlen); 427 } 428 if (len % cc->cipher->block_size) 429 return SSH_ERR_INVALID_ARGUMENT; 430 if (EVP_Cipher(&cc->evp, dest + aadlen, (u_char *)src + aadlen, 431 len) < 0) 432 return SSH_ERR_LIBCRYPTO_ERROR; 433 if (authlen) { 434 /* compute tag (on encrypt) or verify tag (on decrypt) */ 435 if (EVP_Cipher(&cc->evp, NULL, NULL, 0) < 0) 436 return cc->encrypt ? 437 SSH_ERR_LIBCRYPTO_ERROR : SSH_ERR_MAC_INVALID; 438 if (cc->encrypt && 439 !EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_GET_TAG, 440 authlen, dest + aadlen + len)) 441 return SSH_ERR_LIBCRYPTO_ERROR; 442 } 443 return 0; 444 #endif 445 } 446 447 /* Extract the packet length, including any decryption necessary beforehand */ 448 int 449 cipher_get_length(struct sshcipher_ctx *cc, u_int *plenp, u_int seqnr, 450 const u_char *cp, u_int len) 451 { 452 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 453 return chachapoly_get_length(&cc->cp_ctx, plenp, seqnr, 454 cp, len); 455 if (len < 4) 456 return SSH_ERR_MESSAGE_INCOMPLETE; 457 *plenp = get_u32(cp); 458 return 0; 459 } 460 461 int 462 cipher_cleanup(struct sshcipher_ctx *cc) 463 { 464 if (cc == NULL || cc->cipher == NULL) 465 return 0; 466 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 467 explicit_bzero(&cc->cp_ctx, sizeof(cc->cp_ctx)); 468 else if ((cc->cipher->flags & CFLAG_AESCTR) != 0) 469 explicit_bzero(&cc->ac_ctx, sizeof(cc->ac_ctx)); 470 #ifdef WITH_OPENSSL 471 else if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0) 472 return SSH_ERR_LIBCRYPTO_ERROR; 473 #endif 474 return 0; 475 } 476 477 /* 478 * Selects the cipher, and keys if by computing the MD5 checksum of the 479 * passphrase and using the resulting 16 bytes as the key. 480 */ 481 int 482 cipher_set_key_string(struct sshcipher_ctx *cc, const struct sshcipher *cipher, 483 const char *passphrase, int do_encrypt) 484 { 485 u_char digest[16]; 486 int r = SSH_ERR_INTERNAL_ERROR; 487 488 if ((r = ssh_digest_memory(SSH_DIGEST_MD5, 489 passphrase, strlen(passphrase), 490 digest, sizeof(digest))) != 0) 491 goto out; 492 493 r = cipher_init(cc, cipher, digest, 16, NULL, 0, do_encrypt); 494 out: 495 explicit_bzero(digest, sizeof(digest)); 496 return r; 497 } 498 499 /* 500 * Exports an IV from the sshcipher_ctx required to export the key 501 * state back from the unprivileged child to the privileged parent 502 * process. 503 */ 504 int 505 cipher_get_keyiv_len(const struct sshcipher_ctx *cc) 506 { 507 const struct sshcipher *c = cc->cipher; 508 int ivlen = 0; 509 510 if (c->number == SSH_CIPHER_3DES) 511 ivlen = 24; 512 else if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 513 ivlen = 0; 514 else if ((cc->cipher->flags & CFLAG_AESCTR) != 0) 515 ivlen = sizeof(cc->ac_ctx.ctr); 516 #ifdef WITH_OPENSSL 517 else 518 ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp); 519 #endif /* WITH_OPENSSL */ 520 return (ivlen); 521 } 522 523 int 524 cipher_get_keyiv(struct sshcipher_ctx *cc, u_char *iv, u_int len) 525 { 526 const struct sshcipher *c = cc->cipher; 527 #ifdef WITH_OPENSSL 528 int evplen; 529 #endif 530 531 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) { 532 if (len != 0) 533 return SSH_ERR_INVALID_ARGUMENT; 534 return 0; 535 } 536 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) { 537 if (len != sizeof(cc->ac_ctx.ctr)) 538 return SSH_ERR_INVALID_ARGUMENT; 539 memcpy(iv, cc->ac_ctx.ctr, len); 540 return 0; 541 } 542 if ((cc->cipher->flags & CFLAG_NONE) != 0) 543 return 0; 544 545 switch (c->number) { 546 #ifdef WITH_OPENSSL 547 case SSH_CIPHER_SSH2: 548 case SSH_CIPHER_DES: 549 case SSH_CIPHER_BLOWFISH: 550 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp); 551 if (evplen == 0) 552 return 0; 553 else if (evplen < 0) 554 return SSH_ERR_LIBCRYPTO_ERROR; 555 if ((u_int)evplen != len) 556 return SSH_ERR_INVALID_ARGUMENT; 557 #ifndef OPENSSL_HAVE_EVPCTR 558 if (c->evptype == evp_aes_128_ctr) 559 ssh_aes_ctr_iv(&cc->evp, 0, iv, len); 560 else 561 #endif 562 if (cipher_authlen(c)) { 563 if (!EVP_CIPHER_CTX_ctrl(&cc->evp, EVP_CTRL_GCM_IV_GEN, 564 len, iv)) 565 return SSH_ERR_LIBCRYPTO_ERROR; 566 } else 567 memcpy(iv, cc->evp.iv, len); 568 break; 569 #endif 570 #ifdef WITH_SSH1 571 case SSH_CIPHER_3DES: 572 return ssh1_3des_iv(&cc->evp, 0, iv, 24); 573 #endif 574 default: 575 return SSH_ERR_INVALID_ARGUMENT; 576 } 577 return 0; 578 } 579 580 int 581 cipher_set_keyiv(struct sshcipher_ctx *cc, const u_char *iv) 582 { 583 const struct sshcipher *c = cc->cipher; 584 #ifdef WITH_OPENSSL 585 int evplen = 0; 586 #endif 587 588 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 589 return 0; 590 if ((cc->cipher->flags & CFLAG_NONE) != 0) 591 return 0; 592 593 switch (c->number) { 594 #ifdef WITH_OPENSSL 595 case SSH_CIPHER_SSH2: 596 case SSH_CIPHER_DES: 597 case SSH_CIPHER_BLOWFISH: 598 evplen = EVP_CIPHER_CTX_iv_length(&cc->evp); 599 if (evplen <= 0) 600 return SSH_ERR_LIBCRYPTO_ERROR; 601 if (cipher_authlen(c)) { 602 /* XXX iv arg is const, but EVP_CIPHER_CTX_ctrl isn't */ 603 if (!EVP_CIPHER_CTX_ctrl(&cc->evp, 604 EVP_CTRL_GCM_SET_IV_FIXED, -1, (void *)iv)) 605 return SSH_ERR_LIBCRYPTO_ERROR; 606 } else 607 memcpy(cc->evp.iv, iv, evplen); 608 break; 609 #endif 610 #ifdef WITH_SSH1 611 case SSH_CIPHER_3DES: 612 return ssh1_3des_iv(&cc->evp, 1, (u_char *)iv, 24); 613 #endif 614 default: 615 return SSH_ERR_INVALID_ARGUMENT; 616 } 617 return 0; 618 } 619 620 #ifdef WITH_OPENSSL 621 #define EVP_X_STATE(evp) (evp).cipher_data 622 #define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size 623 #endif 624 625 int 626 cipher_get_keycontext(const struct sshcipher_ctx *cc, u_char *dat) 627 { 628 #ifdef WITH_OPENSSL 629 const struct sshcipher *c = cc->cipher; 630 int plen = 0; 631 632 if (c->evptype == EVP_rc4) { 633 plen = EVP_X_STATE_LEN(cc->evp); 634 if (dat == NULL) 635 return (plen); 636 memcpy(dat, EVP_X_STATE(cc->evp), plen); 637 } 638 return (plen); 639 #else 640 return 0; 641 #endif 642 } 643 644 void 645 cipher_set_keycontext(struct sshcipher_ctx *cc, const u_char *dat) 646 { 647 #ifdef WITH_OPENSSL 648 const struct sshcipher *c = cc->cipher; 649 int plen; 650 651 if (c->evptype == EVP_rc4) { 652 plen = EVP_X_STATE_LEN(cc->evp); 653 memcpy(EVP_X_STATE(cc->evp), dat, plen); 654 } 655 #endif 656 } 657