1 /* $OpenBSD: cipher.c,v 1.102 2016/08/03 05:41:57 djm 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_ctx { 61 int plaintext; 62 int encrypt; 63 EVP_CIPHER_CTX *evp; 64 struct chachapoly_ctx cp_ctx; /* XXX union with evp? */ 65 struct aesctr_ctx ac_ctx; /* XXX union with evp? */ 66 const struct sshcipher *cipher; 67 }; 68 69 struct sshcipher { 70 char *name; 71 int number; /* for ssh1 only */ 72 u_int block_size; 73 u_int key_len; 74 u_int iv_len; /* defaults to block_size */ 75 u_int auth_len; 76 u_int discard_len; 77 u_int flags; 78 #define CFLAG_CBC (1<<0) 79 #define CFLAG_CHACHAPOLY (1<<1) 80 #define CFLAG_AESCTR (1<<2) 81 #define CFLAG_NONE (1<<3) 82 #ifdef WITH_OPENSSL 83 const EVP_CIPHER *(*evptype)(void); 84 #else 85 void *ignored; 86 #endif 87 }; 88 89 static const struct sshcipher ciphers[] = { 90 #ifdef WITH_SSH1 91 { "des", SSH_CIPHER_DES, 8, 8, 0, 0, 0, 1, EVP_des_cbc }, 92 { "3des", SSH_CIPHER_3DES, 8, 16, 0, 0, 0, 1, evp_ssh1_3des }, 93 # ifndef OPENSSL_NO_BF 94 { "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, 0, 0, 0, 1, evp_ssh1_bf }, 95 # endif /* OPENSSL_NO_BF */ 96 #endif /* WITH_SSH1 */ 97 #ifdef WITH_OPENSSL 98 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, 0, EVP_enc_null }, 99 { "3des-cbc", SSH_CIPHER_SSH2, 8, 24, 0, 0, 0, 1, EVP_des_ede3_cbc }, 100 # ifndef OPENSSL_NO_BF 101 { "blowfish-cbc", 102 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_bf_cbc }, 103 # endif /* OPENSSL_NO_BF */ 104 # ifndef OPENSSL_NO_CAST 105 { "cast128-cbc", 106 SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 1, EVP_cast5_cbc }, 107 # endif /* OPENSSL_NO_CAST */ 108 # ifndef OPENSSL_NO_RC4 109 { "arcfour", SSH_CIPHER_SSH2, 8, 16, 0, 0, 0, 0, EVP_rc4 }, 110 { "arcfour128", SSH_CIPHER_SSH2, 8, 16, 0, 0, 1536, 0, EVP_rc4 }, 111 { "arcfour256", SSH_CIPHER_SSH2, 8, 32, 0, 0, 1536, 0, EVP_rc4 }, 112 # endif /* OPENSSL_NO_RC4 */ 113 { "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 1, EVP_aes_128_cbc }, 114 { "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 1, EVP_aes_192_cbc }, 115 { "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc }, 116 { "rijndael-cbc@lysator.liu.se", 117 SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 1, EVP_aes_256_cbc }, 118 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, 0, EVP_aes_128_ctr }, 119 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, 0, EVP_aes_192_ctr }, 120 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, 0, EVP_aes_256_ctr }, 121 # ifdef OPENSSL_HAVE_EVPGCM 122 { "aes128-gcm@openssh.com", 123 SSH_CIPHER_SSH2, 16, 16, 12, 16, 0, 0, EVP_aes_128_gcm }, 124 { "aes256-gcm@openssh.com", 125 SSH_CIPHER_SSH2, 16, 32, 12, 16, 0, 0, EVP_aes_256_gcm }, 126 # endif /* OPENSSL_HAVE_EVPGCM */ 127 #else /* WITH_OPENSSL */ 128 { "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, 0, 0, CFLAG_AESCTR, NULL }, 129 { "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, 0, 0, CFLAG_AESCTR, NULL }, 130 { "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, 0, 0, CFLAG_AESCTR, NULL }, 131 { "none", SSH_CIPHER_NONE, 8, 0, 0, 0, 0, CFLAG_NONE, NULL }, 132 #endif /* WITH_OPENSSL */ 133 { "chacha20-poly1305@openssh.com", 134 SSH_CIPHER_SSH2, 8, 64, 0, 16, 0, CFLAG_CHACHAPOLY, NULL }, 135 136 { NULL, SSH_CIPHER_INVALID, 0, 0, 0, 0, 0, 0, NULL } 137 }; 138 139 /*--*/ 140 141 /* Returns a comma-separated list of supported ciphers. */ 142 char * 143 cipher_alg_list(char sep, int auth_only) 144 { 145 char *tmp, *ret = NULL; 146 size_t nlen, rlen = 0; 147 const struct sshcipher *c; 148 149 for (c = ciphers; c->name != NULL; c++) { 150 if (c->number != SSH_CIPHER_SSH2) 151 continue; 152 if (auth_only && c->auth_len == 0) 153 continue; 154 if (ret != NULL) 155 ret[rlen++] = sep; 156 nlen = strlen(c->name); 157 if ((tmp = realloc(ret, rlen + nlen + 2)) == NULL) { 158 free(ret); 159 return NULL; 160 } 161 ret = tmp; 162 memcpy(ret + rlen, c->name, nlen + 1); 163 rlen += nlen; 164 } 165 return ret; 166 } 167 168 u_int 169 cipher_blocksize(const struct sshcipher *c) 170 { 171 return (c->block_size); 172 } 173 174 u_int 175 cipher_keylen(const struct sshcipher *c) 176 { 177 return (c->key_len); 178 } 179 180 u_int 181 cipher_seclen(const struct sshcipher *c) 182 { 183 if (strcmp("3des-cbc", c->name) == 0) 184 return 14; 185 return cipher_keylen(c); 186 } 187 188 u_int 189 cipher_authlen(const struct sshcipher *c) 190 { 191 return (c->auth_len); 192 } 193 194 u_int 195 cipher_ivlen(const struct sshcipher *c) 196 { 197 /* 198 * Default is cipher block size, except for chacha20+poly1305 that 199 * needs no IV. XXX make iv_len == -1 default? 200 */ 201 return (c->iv_len != 0 || (c->flags & CFLAG_CHACHAPOLY) != 0) ? 202 c->iv_len : c->block_size; 203 } 204 205 u_int 206 cipher_get_number(const struct sshcipher *c) 207 { 208 return (c->number); 209 } 210 211 u_int 212 cipher_is_cbc(const struct sshcipher *c) 213 { 214 return (c->flags & CFLAG_CBC) != 0; 215 } 216 217 u_int 218 cipher_ctx_is_plaintext(struct sshcipher_ctx *cc) 219 { 220 return cc->plaintext; 221 } 222 223 u_int 224 cipher_ctx_get_number(struct sshcipher_ctx *cc) 225 { 226 return cc->cipher->number; 227 } 228 229 u_int 230 cipher_mask_ssh1(int client) 231 { 232 u_int mask = 0; 233 mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */ 234 mask |= 1 << SSH_CIPHER_BLOWFISH; 235 if (client) { 236 mask |= 1 << SSH_CIPHER_DES; 237 } 238 return mask; 239 } 240 241 const struct sshcipher * 242 cipher_by_name(const char *name) 243 { 244 const struct sshcipher *c; 245 for (c = ciphers; c->name != NULL; c++) 246 if (strcmp(c->name, name) == 0) 247 return c; 248 return NULL; 249 } 250 251 const struct sshcipher * 252 cipher_by_number(int id) 253 { 254 const struct sshcipher *c; 255 for (c = ciphers; c->name != NULL; c++) 256 if (c->number == id) 257 return c; 258 return NULL; 259 } 260 261 #define CIPHER_SEP "," 262 int 263 ciphers_valid(const char *names) 264 { 265 const struct sshcipher *c; 266 char *cipher_list, *cp; 267 char *p; 268 269 if (names == NULL || strcmp(names, "") == 0) 270 return 0; 271 if ((cipher_list = cp = strdup(names)) == NULL) 272 return 0; 273 for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0'; 274 (p = strsep(&cp, CIPHER_SEP))) { 275 c = cipher_by_name(p); 276 if (c == NULL || c->number != SSH_CIPHER_SSH2) { 277 free(cipher_list); 278 return 0; 279 } 280 } 281 free(cipher_list); 282 return 1; 283 } 284 285 /* 286 * Parses the name of the cipher. Returns the number of the corresponding 287 * cipher, or -1 on error. 288 */ 289 290 int 291 cipher_number(const char *name) 292 { 293 const struct sshcipher *c; 294 if (name == NULL) 295 return -1; 296 for (c = ciphers; c->name != NULL; c++) 297 if (strcasecmp(c->name, name) == 0) 298 return c->number; 299 return -1; 300 } 301 302 char * 303 cipher_name(int id) 304 { 305 const struct sshcipher *c = cipher_by_number(id); 306 return (c==NULL) ? "<unknown>" : c->name; 307 } 308 309 const char * 310 cipher_warning_message(const struct sshcipher_ctx *cc) 311 { 312 if (cc == NULL || cc->cipher == NULL) 313 return NULL; 314 if (cc->cipher->number == SSH_CIPHER_DES) 315 return "use of DES is strongly discouraged due to " 316 "cryptographic weaknesses"; 317 return NULL; 318 } 319 320 int 321 cipher_init(struct sshcipher_ctx **ccp, const struct sshcipher *cipher, 322 const u_char *key, u_int keylen, const u_char *iv, u_int ivlen, 323 int do_encrypt) 324 { 325 struct sshcipher_ctx *cc = NULL; 326 int ret = SSH_ERR_INTERNAL_ERROR; 327 #ifdef WITH_OPENSSL 328 const EVP_CIPHER *type; 329 int klen; 330 u_char *junk, *discard; 331 #endif 332 333 *ccp = NULL; 334 if ((cc = calloc(sizeof(*cc), 1)) == NULL) 335 return SSH_ERR_ALLOC_FAIL; 336 337 if (cipher->number == SSH_CIPHER_DES) { 338 if (keylen > 8) 339 keylen = 8; 340 } 341 342 cc->plaintext = (cipher->number == SSH_CIPHER_NONE); 343 cc->encrypt = do_encrypt; 344 345 if (keylen < cipher->key_len || 346 (iv != NULL && ivlen < cipher_ivlen(cipher))) { 347 ret = SSH_ERR_INVALID_ARGUMENT; 348 goto out; 349 } 350 351 cc->cipher = cipher; 352 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) { 353 ret = chachapoly_init(&cc->cp_ctx, key, keylen); 354 goto out; 355 } 356 #ifndef WITH_OPENSSL 357 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) { 358 aesctr_keysetup(&cc->ac_ctx, key, 8 * keylen, 8 * ivlen); 359 aesctr_ivsetup(&cc->ac_ctx, iv); 360 ret = 0; 361 goto out; 362 } 363 if ((cc->cipher->flags & CFLAG_NONE) != 0) { 364 ret = 0; 365 goto out; 366 } 367 ret = SSH_ERR_INVALID_ARGUMENT; 368 goto out; 369 #else /* WITH_OPENSSL */ 370 type = (*cipher->evptype)(); 371 if ((cc->evp = EVP_CIPHER_CTX_new()) == NULL) { 372 ret = SSH_ERR_ALLOC_FAIL; 373 goto out; 374 } 375 if (EVP_CipherInit(cc->evp, type, NULL, (u_char *)iv, 376 (do_encrypt == CIPHER_ENCRYPT)) == 0) { 377 ret = SSH_ERR_LIBCRYPTO_ERROR; 378 goto out; 379 } 380 if (cipher_authlen(cipher) && 381 !EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_SET_IV_FIXED, 382 -1, (u_char *)iv)) { 383 ret = SSH_ERR_LIBCRYPTO_ERROR; 384 goto out; 385 } 386 klen = EVP_CIPHER_CTX_key_length(cc->evp); 387 if (klen > 0 && keylen != (u_int)klen) { 388 if (EVP_CIPHER_CTX_set_key_length(cc->evp, keylen) == 0) { 389 ret = SSH_ERR_LIBCRYPTO_ERROR; 390 goto out; 391 } 392 } 393 if (EVP_CipherInit(cc->evp, NULL, (u_char *)key, NULL, -1) == 0) { 394 ret = SSH_ERR_LIBCRYPTO_ERROR; 395 goto out; 396 } 397 398 if (cipher->discard_len > 0) { 399 if ((junk = malloc(cipher->discard_len)) == NULL || 400 (discard = malloc(cipher->discard_len)) == NULL) { 401 free(junk); 402 ret = SSH_ERR_ALLOC_FAIL; 403 goto out; 404 } 405 ret = EVP_Cipher(cc->evp, discard, junk, cipher->discard_len); 406 explicit_bzero(discard, cipher->discard_len); 407 free(junk); 408 free(discard); 409 if (ret != 1) { 410 ret = SSH_ERR_LIBCRYPTO_ERROR; 411 goto out; 412 } 413 } 414 ret = 0; 415 #endif /* WITH_OPENSSL */ 416 out: 417 if (ret == 0) { 418 /* success */ 419 *ccp = cc; 420 } else { 421 if (cc != NULL) { 422 #ifdef WITH_OPENSSL 423 if (cc->evp != NULL) 424 EVP_CIPHER_CTX_free(cc->evp); 425 #endif /* WITH_OPENSSL */ 426 explicit_bzero(cc, sizeof(*cc)); 427 free(cc); 428 } 429 } 430 return ret; 431 } 432 433 /* 434 * cipher_crypt() operates as following: 435 * Copy 'aadlen' bytes (without en/decryption) from 'src' to 'dest'. 436 * Theses bytes are treated as additional authenticated data for 437 * authenticated encryption modes. 438 * En/Decrypt 'len' bytes at offset 'aadlen' from 'src' to 'dest'. 439 * Use 'authlen' bytes at offset 'len'+'aadlen' as the authentication tag. 440 * This tag is written on encryption and verified on decryption. 441 * Both 'aadlen' and 'authlen' can be set to 0. 442 */ 443 int 444 cipher_crypt(struct sshcipher_ctx *cc, u_int seqnr, u_char *dest, 445 const u_char *src, u_int len, u_int aadlen, u_int authlen) 446 { 447 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) { 448 return chachapoly_crypt(&cc->cp_ctx, seqnr, dest, src, 449 len, aadlen, authlen, cc->encrypt); 450 } 451 #ifndef WITH_OPENSSL 452 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) { 453 if (aadlen) 454 memcpy(dest, src, aadlen); 455 aesctr_encrypt_bytes(&cc->ac_ctx, src + aadlen, 456 dest + aadlen, len); 457 return 0; 458 } 459 if ((cc->cipher->flags & CFLAG_NONE) != 0) { 460 memcpy(dest, src, aadlen + len); 461 return 0; 462 } 463 return SSH_ERR_INVALID_ARGUMENT; 464 #else 465 if (authlen) { 466 u_char lastiv[1]; 467 468 if (authlen != cipher_authlen(cc->cipher)) 469 return SSH_ERR_INVALID_ARGUMENT; 470 /* increment IV */ 471 if (!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_IV_GEN, 472 1, lastiv)) 473 return SSH_ERR_LIBCRYPTO_ERROR; 474 /* set tag on decyption */ 475 if (!cc->encrypt && 476 !EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_SET_TAG, 477 authlen, (u_char *)src + aadlen + len)) 478 return SSH_ERR_LIBCRYPTO_ERROR; 479 } 480 if (aadlen) { 481 if (authlen && 482 EVP_Cipher(cc->evp, NULL, (u_char *)src, aadlen) < 0) 483 return SSH_ERR_LIBCRYPTO_ERROR; 484 memcpy(dest, src, aadlen); 485 } 486 if (len % cc->cipher->block_size) 487 return SSH_ERR_INVALID_ARGUMENT; 488 if (EVP_Cipher(cc->evp, dest + aadlen, (u_char *)src + aadlen, 489 len) < 0) 490 return SSH_ERR_LIBCRYPTO_ERROR; 491 if (authlen) { 492 /* compute tag (on encrypt) or verify tag (on decrypt) */ 493 if (EVP_Cipher(cc->evp, NULL, NULL, 0) < 0) 494 return cc->encrypt ? 495 SSH_ERR_LIBCRYPTO_ERROR : SSH_ERR_MAC_INVALID; 496 if (cc->encrypt && 497 !EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_GET_TAG, 498 authlen, dest + aadlen + len)) 499 return SSH_ERR_LIBCRYPTO_ERROR; 500 } 501 return 0; 502 #endif 503 } 504 505 /* Extract the packet length, including any decryption necessary beforehand */ 506 int 507 cipher_get_length(struct sshcipher_ctx *cc, u_int *plenp, u_int seqnr, 508 const u_char *cp, u_int len) 509 { 510 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 511 return chachapoly_get_length(&cc->cp_ctx, plenp, seqnr, 512 cp, len); 513 if (len < 4) 514 return SSH_ERR_MESSAGE_INCOMPLETE; 515 *plenp = get_u32(cp); 516 return 0; 517 } 518 519 void 520 cipher_free(struct sshcipher_ctx *cc) 521 { 522 if (cc == NULL) 523 return; 524 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 525 explicit_bzero(&cc->cp_ctx, sizeof(cc->cp_ctx)); 526 else if ((cc->cipher->flags & CFLAG_AESCTR) != 0) 527 explicit_bzero(&cc->ac_ctx, sizeof(cc->ac_ctx)); 528 #ifdef WITH_OPENSSL 529 if (cc->evp != NULL) { 530 EVP_CIPHER_CTX_free(cc->evp); 531 cc->evp = NULL; 532 } 533 #endif 534 explicit_bzero(cc, sizeof(*cc)); 535 free(cc); 536 } 537 538 /* 539 * Selects the cipher, and keys if by computing the MD5 checksum of the 540 * passphrase and using the resulting 16 bytes as the key. 541 */ 542 int 543 cipher_set_key_string(struct sshcipher_ctx **ccp, 544 const struct sshcipher *cipher, const char *passphrase, int do_encrypt) 545 { 546 u_char digest[16]; 547 int r = SSH_ERR_INTERNAL_ERROR; 548 549 if ((r = ssh_digest_memory(SSH_DIGEST_MD5, 550 passphrase, strlen(passphrase), 551 digest, sizeof(digest))) != 0) 552 goto out; 553 554 r = cipher_init(ccp, cipher, digest, 16, NULL, 0, do_encrypt); 555 out: 556 explicit_bzero(digest, sizeof(digest)); 557 return r; 558 } 559 560 /* 561 * Exports an IV from the sshcipher_ctx required to export the key 562 * state back from the unprivileged child to the privileged parent 563 * process. 564 */ 565 int 566 cipher_get_keyiv_len(const struct sshcipher_ctx *cc) 567 { 568 const struct sshcipher *c = cc->cipher; 569 int ivlen = 0; 570 571 if (c->number == SSH_CIPHER_3DES) 572 ivlen = 24; 573 else if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 574 ivlen = 0; 575 else if ((cc->cipher->flags & CFLAG_AESCTR) != 0) 576 ivlen = sizeof(cc->ac_ctx.ctr); 577 #ifdef WITH_OPENSSL 578 else 579 ivlen = EVP_CIPHER_CTX_iv_length(cc->evp); 580 #endif /* WITH_OPENSSL */ 581 return (ivlen); 582 } 583 584 int 585 cipher_get_keyiv(struct sshcipher_ctx *cc, u_char *iv, u_int len) 586 { 587 const struct sshcipher *c = cc->cipher; 588 #ifdef WITH_OPENSSL 589 int evplen; 590 #endif 591 592 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) { 593 if (len != 0) 594 return SSH_ERR_INVALID_ARGUMENT; 595 return 0; 596 } 597 if ((cc->cipher->flags & CFLAG_AESCTR) != 0) { 598 if (len != sizeof(cc->ac_ctx.ctr)) 599 return SSH_ERR_INVALID_ARGUMENT; 600 memcpy(iv, cc->ac_ctx.ctr, len); 601 return 0; 602 } 603 if ((cc->cipher->flags & CFLAG_NONE) != 0) 604 return 0; 605 606 switch (c->number) { 607 #ifdef WITH_OPENSSL 608 case SSH_CIPHER_SSH2: 609 case SSH_CIPHER_DES: 610 case SSH_CIPHER_BLOWFISH: 611 evplen = EVP_CIPHER_CTX_iv_length(cc->evp); 612 if (evplen == 0) 613 return 0; 614 else if (evplen < 0) 615 return SSH_ERR_LIBCRYPTO_ERROR; 616 if ((u_int)evplen != len) 617 return SSH_ERR_INVALID_ARGUMENT; 618 #ifndef OPENSSL_HAVE_EVPCTR 619 if (c->evptype == evp_aes_128_ctr) 620 ssh_aes_ctr_iv(cc->evp, 0, iv, len); 621 else 622 #endif 623 if (cipher_authlen(c)) { 624 if (!EVP_CIPHER_CTX_ctrl(cc->evp, EVP_CTRL_GCM_IV_GEN, 625 len, iv)) 626 return SSH_ERR_LIBCRYPTO_ERROR; 627 } else 628 memcpy(iv, cc->evp->iv, len); 629 break; 630 #endif 631 #ifdef WITH_SSH1 632 case SSH_CIPHER_3DES: 633 return ssh1_3des_iv(cc->evp, 0, iv, 24); 634 #endif 635 default: 636 return SSH_ERR_INVALID_ARGUMENT; 637 } 638 return 0; 639 } 640 641 int 642 cipher_set_keyiv(struct sshcipher_ctx *cc, const u_char *iv) 643 { 644 const struct sshcipher *c = cc->cipher; 645 #ifdef WITH_OPENSSL 646 int evplen = 0; 647 #endif 648 649 if ((cc->cipher->flags & CFLAG_CHACHAPOLY) != 0) 650 return 0; 651 if ((cc->cipher->flags & CFLAG_NONE) != 0) 652 return 0; 653 654 switch (c->number) { 655 #ifdef WITH_OPENSSL 656 case SSH_CIPHER_SSH2: 657 case SSH_CIPHER_DES: 658 case SSH_CIPHER_BLOWFISH: 659 evplen = EVP_CIPHER_CTX_iv_length(cc->evp); 660 if (evplen <= 0) 661 return SSH_ERR_LIBCRYPTO_ERROR; 662 #ifndef OPENSSL_HAVE_EVPCTR 663 /* XXX iv arg is const, but ssh_aes_ctr_iv isn't */ 664 if (c->evptype == evp_aes_128_ctr) 665 ssh_aes_ctr_iv(cc->evp, 1, (u_char *)iv, evplen); 666 else 667 #endif 668 if (cipher_authlen(c)) { 669 /* XXX iv arg is const, but EVP_CIPHER_CTX_ctrl isn't */ 670 if (!EVP_CIPHER_CTX_ctrl(cc->evp, 671 EVP_CTRL_GCM_SET_IV_FIXED, -1, (void *)iv)) 672 return SSH_ERR_LIBCRYPTO_ERROR; 673 } else 674 memcpy(cc->evp->iv, iv, evplen); 675 break; 676 #endif 677 #ifdef WITH_SSH1 678 case SSH_CIPHER_3DES: 679 return ssh1_3des_iv(cc->evp, 1, (u_char *)iv, 24); 680 #endif 681 default: 682 return SSH_ERR_INVALID_ARGUMENT; 683 } 684 return 0; 685 } 686 687 #ifdef WITH_OPENSSL 688 #define EVP_X_STATE(evp) (evp)->cipher_data 689 #define EVP_X_STATE_LEN(evp) (evp)->cipher->ctx_size 690 #endif 691 692 int 693 cipher_get_keycontext(const struct sshcipher_ctx *cc, u_char *dat) 694 { 695 #if defined(WITH_OPENSSL) && !defined(OPENSSL_NO_RC4) 696 const struct sshcipher *c = cc->cipher; 697 int plen = 0; 698 699 if (c->evptype == EVP_rc4) { 700 plen = EVP_X_STATE_LEN(cc->evp); 701 if (dat == NULL) 702 return (plen); 703 memcpy(dat, EVP_X_STATE(cc->evp), plen); 704 } 705 return (plen); 706 #else 707 return 0; 708 #endif 709 } 710 711 void 712 cipher_set_keycontext(struct sshcipher_ctx *cc, const u_char *dat) 713 { 714 #if defined(WITH_OPENSSL) && !defined(OPENSSL_NO_RC4) 715 const struct sshcipher *c = cc->cipher; 716 int plen; 717 718 if (c->evptype == EVP_rc4) { 719 plen = EVP_X_STATE_LEN(cc->evp); 720 memcpy(EVP_X_STATE(cc->evp), dat, plen); 721 } 722 #endif 723 } 724