1/* 2 * linux/net/sunrpc/gss_krb5_crypto.c 3 * 4 * Copyright (c) 2000-2008 The Regents of the University of Michigan. 5 * All rights reserved. 6 * 7 * Andy Adamson <andros@umich.edu> 8 * Bruce Fields <bfields@umich.edu> 9 */ 10 11/* 12 * Copyright (C) 1998 by the FundsXpress, INC. 13 * 14 * All rights reserved. 15 * 16 * Export of this software from the United States of America may require 17 * a specific license from the United States Government. It is the 18 * responsibility of any person or organization contemplating export to 19 * obtain such a license before exporting. 20 * 21 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and 22 * distribute this software and its documentation for any purpose and 23 * without fee is hereby granted, provided that the above copyright 24 * notice appear in all copies and that both that copyright notice and 25 * this permission notice appear in supporting documentation, and that 26 * the name of FundsXpress. not be used in advertising or publicity pertaining 27 * to distribution of the software without specific, written prior 28 * permission. FundsXpress makes no representations about the suitability of 29 * this software for any purpose. It is provided "as is" without express 30 * or implied warranty. 31 * 32 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 33 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 34 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 35 */ 36 37#include <linux/err.h> 38#include <linux/types.h> 39#include <linux/mm.h> 40#include <linux/scatterlist.h> 41#include <linux/crypto.h> 42#include <linux/highmem.h> 43#include <linux/pagemap.h> 44#include <linux/random.h> 45#include <linux/sunrpc/gss_krb5.h> 46#include <linux/sunrpc/xdr.h> 47 48#ifdef RPC_DEBUG 49# define RPCDBG_FACILITY RPCDBG_AUTH 50#endif 51 52u32 53krb5_encrypt( 54 struct crypto_blkcipher *tfm, 55 void * iv, 56 void * in, 57 void * out, 58 int length) 59{ 60 u32 ret = -EINVAL; 61 struct scatterlist sg[1]; 62 u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0}; 63 struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv }; 64 65 if (length % crypto_blkcipher_blocksize(tfm) != 0) 66 goto out; 67 68 if (crypto_blkcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) { 69 dprintk("RPC: gss_k5encrypt: tfm iv size too large %d\n", 70 crypto_blkcipher_ivsize(tfm)); 71 goto out; 72 } 73 74 if (iv) 75 memcpy(local_iv, iv, crypto_blkcipher_ivsize(tfm)); 76 77 memcpy(out, in, length); 78 sg_init_one(sg, out, length); 79 80 ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length); 81out: 82 dprintk("RPC: krb5_encrypt returns %d\n", ret); 83 return ret; 84} 85 86u32 87krb5_decrypt( 88 struct crypto_blkcipher *tfm, 89 void * iv, 90 void * in, 91 void * out, 92 int length) 93{ 94 u32 ret = -EINVAL; 95 struct scatterlist sg[1]; 96 u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0}; 97 struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv }; 98 99 if (length % crypto_blkcipher_blocksize(tfm) != 0) 100 goto out; 101 102 if (crypto_blkcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) { 103 dprintk("RPC: gss_k5decrypt: tfm iv size too large %d\n", 104 crypto_blkcipher_ivsize(tfm)); 105 goto out; 106 } 107 if (iv) 108 memcpy(local_iv,iv, crypto_blkcipher_ivsize(tfm)); 109 110 memcpy(out, in, length); 111 sg_init_one(sg, out, length); 112 113 ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length); 114out: 115 dprintk("RPC: gss_k5decrypt returns %d\n",ret); 116 return ret; 117} 118 119static int 120checksummer(struct scatterlist *sg, void *data) 121{ 122 struct hash_desc *desc = data; 123 124 return crypto_hash_update(desc, sg, sg->length); 125} 126 127static int 128arcfour_hmac_md5_usage_to_salt(unsigned int usage, u8 salt[4]) 129{ 130 unsigned int ms_usage; 131 132 switch (usage) { 133 case KG_USAGE_SIGN: 134 ms_usage = 15; 135 break; 136 case KG_USAGE_SEAL: 137 ms_usage = 13; 138 break; 139 default: 140 return -EINVAL; 141 } 142 salt[0] = (ms_usage >> 0) & 0xff; 143 salt[1] = (ms_usage >> 8) & 0xff; 144 salt[2] = (ms_usage >> 16) & 0xff; 145 salt[3] = (ms_usage >> 24) & 0xff; 146 147 return 0; 148} 149 150static u32 151make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen, 152 struct xdr_buf *body, int body_offset, u8 *cksumkey, 153 unsigned int usage, struct xdr_netobj *cksumout) 154{ 155 struct hash_desc desc; 156 struct scatterlist sg[1]; 157 int err; 158 u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN]; 159 u8 rc4salt[4]; 160 struct crypto_hash *md5; 161 struct crypto_hash *hmac_md5; 162 163 if (cksumkey == NULL) 164 return GSS_S_FAILURE; 165 166 if (cksumout->len < kctx->gk5e->cksumlength) { 167 dprintk("%s: checksum buffer length, %u, too small for %s\n", 168 __func__, cksumout->len, kctx->gk5e->name); 169 return GSS_S_FAILURE; 170 } 171 172 if (arcfour_hmac_md5_usage_to_salt(usage, rc4salt)) { 173 dprintk("%s: invalid usage value %u\n", __func__, usage); 174 return GSS_S_FAILURE; 175 } 176 177 md5 = crypto_alloc_hash("md5", 0, CRYPTO_ALG_ASYNC); 178 if (IS_ERR(md5)) 179 return GSS_S_FAILURE; 180 181 hmac_md5 = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, 182 CRYPTO_ALG_ASYNC); 183 if (IS_ERR(hmac_md5)) { 184 crypto_free_hash(md5); 185 return GSS_S_FAILURE; 186 } 187 188 desc.tfm = md5; 189 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 190 191 err = crypto_hash_init(&desc); 192 if (err) 193 goto out; 194 sg_init_one(sg, rc4salt, 4); 195 err = crypto_hash_update(&desc, sg, 4); 196 if (err) 197 goto out; 198 199 sg_init_one(sg, header, hdrlen); 200 err = crypto_hash_update(&desc, sg, hdrlen); 201 if (err) 202 goto out; 203 err = xdr_process_buf(body, body_offset, body->len - body_offset, 204 checksummer, &desc); 205 if (err) 206 goto out; 207 err = crypto_hash_final(&desc, checksumdata); 208 if (err) 209 goto out; 210 211 desc.tfm = hmac_md5; 212 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 213 214 err = crypto_hash_init(&desc); 215 if (err) 216 goto out; 217 err = crypto_hash_setkey(hmac_md5, cksumkey, kctx->gk5e->keylength); 218 if (err) 219 goto out; 220 221 sg_init_one(sg, checksumdata, crypto_hash_digestsize(md5)); 222 err = crypto_hash_digest(&desc, sg, crypto_hash_digestsize(md5), 223 checksumdata); 224 if (err) 225 goto out; 226 227 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength); 228 cksumout->len = kctx->gk5e->cksumlength; 229out: 230 crypto_free_hash(md5); 231 crypto_free_hash(hmac_md5); 232 return err ? GSS_S_FAILURE : 0; 233} 234 235/* 236 * checksum the plaintext data and hdrlen bytes of the token header 237 * The checksum is performed over the first 8 bytes of the 238 * gss token header and then over the data body 239 */ 240u32 241make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen, 242 struct xdr_buf *body, int body_offset, u8 *cksumkey, 243 unsigned int usage, struct xdr_netobj *cksumout) 244{ 245 struct hash_desc desc; 246 struct scatterlist sg[1]; 247 int err; 248 u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN]; 249 unsigned int checksumlen; 250 251 if (kctx->gk5e->ctype == CKSUMTYPE_HMAC_MD5_ARCFOUR) 252 return make_checksum_hmac_md5(kctx, header, hdrlen, 253 body, body_offset, 254 cksumkey, usage, cksumout); 255 256 if (cksumout->len < kctx->gk5e->cksumlength) { 257 dprintk("%s: checksum buffer length, %u, too small for %s\n", 258 __func__, cksumout->len, kctx->gk5e->name); 259 return GSS_S_FAILURE; 260 } 261 262 desc.tfm = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC); 263 if (IS_ERR(desc.tfm)) 264 return GSS_S_FAILURE; 265 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 266 267 checksumlen = crypto_hash_digestsize(desc.tfm); 268 269 if (cksumkey != NULL) { 270 err = crypto_hash_setkey(desc.tfm, cksumkey, 271 kctx->gk5e->keylength); 272 if (err) 273 goto out; 274 } 275 276 err = crypto_hash_init(&desc); 277 if (err) 278 goto out; 279 sg_init_one(sg, header, hdrlen); 280 err = crypto_hash_update(&desc, sg, hdrlen); 281 if (err) 282 goto out; 283 err = xdr_process_buf(body, body_offset, body->len - body_offset, 284 checksummer, &desc); 285 if (err) 286 goto out; 287 err = crypto_hash_final(&desc, checksumdata); 288 if (err) 289 goto out; 290 291 switch (kctx->gk5e->ctype) { 292 case CKSUMTYPE_RSA_MD5: 293 err = kctx->gk5e->encrypt(kctx->seq, NULL, checksumdata, 294 checksumdata, checksumlen); 295 if (err) 296 goto out; 297 memcpy(cksumout->data, 298 checksumdata + checksumlen - kctx->gk5e->cksumlength, 299 kctx->gk5e->cksumlength); 300 break; 301 case CKSUMTYPE_HMAC_SHA1_DES3: 302 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength); 303 break; 304 default: 305 BUG(); 306 break; 307 } 308 cksumout->len = kctx->gk5e->cksumlength; 309out: 310 crypto_free_hash(desc.tfm); 311 return err ? GSS_S_FAILURE : 0; 312} 313 314/* 315 * checksum the plaintext data and hdrlen bytes of the token header 316 * Per rfc4121, sec. 4.2.4, the checksum is performed over the data 317 * body then over the first 16 octets of the MIC token 318 * Inclusion of the header data in the calculation of the 319 * checksum is optional. 320 */ 321u32 322make_checksum_v2(struct krb5_ctx *kctx, char *header, int hdrlen, 323 struct xdr_buf *body, int body_offset, u8 *cksumkey, 324 unsigned int usage, struct xdr_netobj *cksumout) 325{ 326 struct hash_desc desc; 327 struct scatterlist sg[1]; 328 int err; 329 u8 checksumdata[GSS_KRB5_MAX_CKSUM_LEN]; 330 unsigned int checksumlen; 331 332 if (kctx->gk5e->keyed_cksum == 0) { 333 dprintk("%s: expected keyed hash for %s\n", 334 __func__, kctx->gk5e->name); 335 return GSS_S_FAILURE; 336 } 337 if (cksumkey == NULL) { 338 dprintk("%s: no key supplied for %s\n", 339 __func__, kctx->gk5e->name); 340 return GSS_S_FAILURE; 341 } 342 343 desc.tfm = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, 344 CRYPTO_ALG_ASYNC); 345 if (IS_ERR(desc.tfm)) 346 return GSS_S_FAILURE; 347 checksumlen = crypto_hash_digestsize(desc.tfm); 348 desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP; 349 350 err = crypto_hash_setkey(desc.tfm, cksumkey, kctx->gk5e->keylength); 351 if (err) 352 goto out; 353 354 err = crypto_hash_init(&desc); 355 if (err) 356 goto out; 357 err = xdr_process_buf(body, body_offset, body->len - body_offset, 358 checksummer, &desc); 359 if (err) 360 goto out; 361 if (header != NULL) { 362 sg_init_one(sg, header, hdrlen); 363 err = crypto_hash_update(&desc, sg, hdrlen); 364 if (err) 365 goto out; 366 } 367 err = crypto_hash_final(&desc, checksumdata); 368 if (err) 369 goto out; 370 371 cksumout->len = kctx->gk5e->cksumlength; 372 373 switch (kctx->gk5e->ctype) { 374 case CKSUMTYPE_HMAC_SHA1_96_AES128: 375 case CKSUMTYPE_HMAC_SHA1_96_AES256: 376 /* note that this truncates the hash */ 377 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength); 378 break; 379 default: 380 BUG(); 381 break; 382 } 383out: 384 crypto_free_hash(desc.tfm); 385 return err ? GSS_S_FAILURE : 0; 386} 387 388struct encryptor_desc { 389 u8 iv[GSS_KRB5_MAX_BLOCKSIZE]; 390 struct blkcipher_desc desc; 391 int pos; 392 struct xdr_buf *outbuf; 393 struct page **pages; 394 struct scatterlist infrags[4]; 395 struct scatterlist outfrags[4]; 396 int fragno; 397 int fraglen; 398}; 399 400static int 401encryptor(struct scatterlist *sg, void *data) 402{ 403 struct encryptor_desc *desc = data; 404 struct xdr_buf *outbuf = desc->outbuf; 405 struct page *in_page; 406 int thislen = desc->fraglen + sg->length; 407 int fraglen, ret; 408 int page_pos; 409 410 /* Worst case is 4 fragments: head, end of page 1, start 411 * of page 2, tail. Anything more is a bug. */ 412 BUG_ON(desc->fragno > 3); 413 414 page_pos = desc->pos - outbuf->head[0].iov_len; 415 if (page_pos >= 0 && page_pos < outbuf->page_len) { 416 /* pages are not in place: */ 417 int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT; 418 in_page = desc->pages[i]; 419 } else { 420 in_page = sg_page(sg); 421 } 422 sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length, 423 sg->offset); 424 sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length, 425 sg->offset); 426 desc->fragno++; 427 desc->fraglen += sg->length; 428 desc->pos += sg->length; 429 430 fraglen = thislen & (crypto_blkcipher_blocksize(desc->desc.tfm) - 1); 431 thislen -= fraglen; 432 433 if (thislen == 0) 434 return 0; 435 436 sg_mark_end(&desc->infrags[desc->fragno - 1]); 437 sg_mark_end(&desc->outfrags[desc->fragno - 1]); 438 439 ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags, 440 desc->infrags, thislen); 441 if (ret) 442 return ret; 443 444 sg_init_table(desc->infrags, 4); 445 sg_init_table(desc->outfrags, 4); 446 447 if (fraglen) { 448 sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen, 449 sg->offset + sg->length - fraglen); 450 desc->infrags[0] = desc->outfrags[0]; 451 sg_assign_page(&desc->infrags[0], in_page); 452 desc->fragno = 1; 453 desc->fraglen = fraglen; 454 } else { 455 desc->fragno = 0; 456 desc->fraglen = 0; 457 } 458 return 0; 459} 460 461int 462gss_encrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf, 463 int offset, struct page **pages) 464{ 465 int ret; 466 struct encryptor_desc desc; 467 468 BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0); 469 470 memset(desc.iv, 0, sizeof(desc.iv)); 471 desc.desc.tfm = tfm; 472 desc.desc.info = desc.iv; 473 desc.desc.flags = 0; 474 desc.pos = offset; 475 desc.outbuf = buf; 476 desc.pages = pages; 477 desc.fragno = 0; 478 desc.fraglen = 0; 479 480 sg_init_table(desc.infrags, 4); 481 sg_init_table(desc.outfrags, 4); 482 483 ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc); 484 return ret; 485} 486 487struct decryptor_desc { 488 u8 iv[GSS_KRB5_MAX_BLOCKSIZE]; 489 struct blkcipher_desc desc; 490 struct scatterlist frags[4]; 491 int fragno; 492 int fraglen; 493}; 494 495static int 496decryptor(struct scatterlist *sg, void *data) 497{ 498 struct decryptor_desc *desc = data; 499 int thislen = desc->fraglen + sg->length; 500 int fraglen, ret; 501 502 /* Worst case is 4 fragments: head, end of page 1, start 503 * of page 2, tail. Anything more is a bug. */ 504 BUG_ON(desc->fragno > 3); 505 sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length, 506 sg->offset); 507 desc->fragno++; 508 desc->fraglen += sg->length; 509 510 fraglen = thislen & (crypto_blkcipher_blocksize(desc->desc.tfm) - 1); 511 thislen -= fraglen; 512 513 if (thislen == 0) 514 return 0; 515 516 sg_mark_end(&desc->frags[desc->fragno - 1]); 517 518 ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags, 519 desc->frags, thislen); 520 if (ret) 521 return ret; 522 523 sg_init_table(desc->frags, 4); 524 525 if (fraglen) { 526 sg_set_page(&desc->frags[0], sg_page(sg), fraglen, 527 sg->offset + sg->length - fraglen); 528 desc->fragno = 1; 529 desc->fraglen = fraglen; 530 } else { 531 desc->fragno = 0; 532 desc->fraglen = 0; 533 } 534 return 0; 535} 536 537int 538gss_decrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf, 539 int offset) 540{ 541 struct decryptor_desc desc; 542 543 /* XXXJBF: */ 544 BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0); 545 546 memset(desc.iv, 0, sizeof(desc.iv)); 547 desc.desc.tfm = tfm; 548 desc.desc.info = desc.iv; 549 desc.desc.flags = 0; 550 desc.fragno = 0; 551 desc.fraglen = 0; 552 553 sg_init_table(desc.frags, 4); 554 555 return xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc); 556} 557 558/* 559 * This function makes the assumption that it was ultimately called 560 * from gss_wrap(). 561 * 562 * The client auth_gss code moves any existing tail data into a 563 * separate page before calling gss_wrap. 564 * The server svcauth_gss code ensures that both the head and the 565 * tail have slack space of RPC_MAX_AUTH_SIZE before calling gss_wrap. 566 * 567 * Even with that guarantee, this function may be called more than 568 * once in the processing of gss_wrap(). The best we can do is 569 * verify at compile-time (see GSS_KRB5_SLACK_CHECK) that the 570 * largest expected shift will fit within RPC_MAX_AUTH_SIZE. 571 * At run-time we can verify that a single invocation of this 572 * function doesn't attempt to use more the RPC_MAX_AUTH_SIZE. 573 */ 574 575int 576xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen) 577{ 578 u8 *p; 579 580 if (shiftlen == 0) 581 return 0; 582 583 BUILD_BUG_ON(GSS_KRB5_MAX_SLACK_NEEDED > RPC_MAX_AUTH_SIZE); 584 BUG_ON(shiftlen > RPC_MAX_AUTH_SIZE); 585 586 p = buf->head[0].iov_base + base; 587 588 memmove(p + shiftlen, p, buf->head[0].iov_len - base); 589 590 buf->head[0].iov_len += shiftlen; 591 buf->len += shiftlen; 592 593 return 0; 594} 595 596static u32 597gss_krb5_cts_crypt(struct crypto_blkcipher *cipher, struct xdr_buf *buf, 598 u32 offset, u8 *iv, struct page **pages, int encrypt) 599{ 600 u32 ret; 601 struct scatterlist sg[1]; 602 struct blkcipher_desc desc = { .tfm = cipher, .info = iv }; 603 u8 data[GSS_KRB5_MAX_BLOCKSIZE * 2]; 604 struct page **save_pages; 605 u32 len = buf->len - offset; 606 607 if (len > ARRAY_SIZE(data)) { 608 WARN_ON(0); 609 return -ENOMEM; 610 } 611 612 /* 613 * For encryption, we want to read from the cleartext 614 * page cache pages, and write the encrypted data to 615 * the supplied xdr_buf pages. 616 */ 617 save_pages = buf->pages; 618 if (encrypt) 619 buf->pages = pages; 620 621 ret = read_bytes_from_xdr_buf(buf, offset, data, len); 622 buf->pages = save_pages; 623 if (ret) 624 goto out; 625 626 sg_init_one(sg, data, len); 627 628 if (encrypt) 629 ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, len); 630 else 631 ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, len); 632 633 if (ret) 634 goto out; 635 636 ret = write_bytes_to_xdr_buf(buf, offset, data, len); 637 638out: 639 return ret; 640} 641 642u32 643gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset, 644 struct xdr_buf *buf, struct page **pages) 645{ 646 u32 err; 647 struct xdr_netobj hmac; 648 u8 *cksumkey; 649 u8 *ecptr; 650 struct crypto_blkcipher *cipher, *aux_cipher; 651 int blocksize; 652 struct page **save_pages; 653 int nblocks, nbytes; 654 struct encryptor_desc desc; 655 u32 cbcbytes; 656 unsigned int usage; 657 658 if (kctx->initiate) { 659 cipher = kctx->initiator_enc; 660 aux_cipher = kctx->initiator_enc_aux; 661 cksumkey = kctx->initiator_integ; 662 usage = KG_USAGE_INITIATOR_SEAL; 663 } else { 664 cipher = kctx->acceptor_enc; 665 aux_cipher = kctx->acceptor_enc_aux; 666 cksumkey = kctx->acceptor_integ; 667 usage = KG_USAGE_ACCEPTOR_SEAL; 668 } 669 blocksize = crypto_blkcipher_blocksize(cipher); 670 671 /* hide the gss token header and insert the confounder */ 672 offset += GSS_KRB5_TOK_HDR_LEN; 673 if (xdr_extend_head(buf, offset, kctx->gk5e->conflen)) 674 return GSS_S_FAILURE; 675 gss_krb5_make_confounder(buf->head[0].iov_base + offset, kctx->gk5e->conflen); 676 offset -= GSS_KRB5_TOK_HDR_LEN; 677 678 if (buf->tail[0].iov_base != NULL) { 679 ecptr = buf->tail[0].iov_base + buf->tail[0].iov_len; 680 } else { 681 buf->tail[0].iov_base = buf->head[0].iov_base 682 + buf->head[0].iov_len; 683 buf->tail[0].iov_len = 0; 684 ecptr = buf->tail[0].iov_base; 685 } 686 687 /* copy plaintext gss token header after filler (if any) */ 688 memcpy(ecptr, buf->head[0].iov_base + offset, GSS_KRB5_TOK_HDR_LEN); 689 buf->tail[0].iov_len += GSS_KRB5_TOK_HDR_LEN; 690 buf->len += GSS_KRB5_TOK_HDR_LEN; 691 692 /* Do the HMAC */ 693 hmac.len = GSS_KRB5_MAX_CKSUM_LEN; 694 hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len; 695 696 /* 697 * When we are called, pages points to the real page cache 698 * data -- which we can't go and encrypt! buf->pages points 699 * to scratch pages which we are going to send off to the 700 * client/server. Swap in the plaintext pages to calculate 701 * the hmac. 702 */ 703 save_pages = buf->pages; 704 buf->pages = pages; 705 706 err = make_checksum_v2(kctx, NULL, 0, buf, 707 offset + GSS_KRB5_TOK_HDR_LEN, 708 cksumkey, usage, &hmac); 709 buf->pages = save_pages; 710 if (err) 711 return GSS_S_FAILURE; 712 713 nbytes = buf->len - offset - GSS_KRB5_TOK_HDR_LEN; 714 nblocks = (nbytes + blocksize - 1) / blocksize; 715 cbcbytes = 0; 716 if (nblocks > 2) 717 cbcbytes = (nblocks - 2) * blocksize; 718 719 memset(desc.iv, 0, sizeof(desc.iv)); 720 721 if (cbcbytes) { 722 desc.pos = offset + GSS_KRB5_TOK_HDR_LEN; 723 desc.fragno = 0; 724 desc.fraglen = 0; 725 desc.pages = pages; 726 desc.outbuf = buf; 727 desc.desc.info = desc.iv; 728 desc.desc.flags = 0; 729 desc.desc.tfm = aux_cipher; 730 731 sg_init_table(desc.infrags, 4); 732 sg_init_table(desc.outfrags, 4); 733 734 err = xdr_process_buf(buf, offset + GSS_KRB5_TOK_HDR_LEN, 735 cbcbytes, encryptor, &desc); 736 if (err) 737 goto out_err; 738 } 739 740 /* Make sure IV carries forward from any CBC results. */ 741 err = gss_krb5_cts_crypt(cipher, buf, 742 offset + GSS_KRB5_TOK_HDR_LEN + cbcbytes, 743 desc.iv, pages, 1); 744 if (err) { 745 err = GSS_S_FAILURE; 746 goto out_err; 747 } 748 749 /* Now update buf to account for HMAC */ 750 buf->tail[0].iov_len += kctx->gk5e->cksumlength; 751 buf->len += kctx->gk5e->cksumlength; 752 753out_err: 754 if (err) 755 err = GSS_S_FAILURE; 756 return err; 757} 758 759u32 760gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf, 761 u32 *headskip, u32 *tailskip) 762{ 763 struct xdr_buf subbuf; 764 u32 ret = 0; 765 u8 *cksum_key; 766 struct crypto_blkcipher *cipher, *aux_cipher; 767 struct xdr_netobj our_hmac_obj; 768 u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN]; 769 u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN]; 770 int nblocks, blocksize, cbcbytes; 771 struct decryptor_desc desc; 772 unsigned int usage; 773 774 if (kctx->initiate) { 775 cipher = kctx->acceptor_enc; 776 aux_cipher = kctx->acceptor_enc_aux; 777 cksum_key = kctx->acceptor_integ; 778 usage = KG_USAGE_ACCEPTOR_SEAL; 779 } else { 780 cipher = kctx->initiator_enc; 781 aux_cipher = kctx->initiator_enc_aux; 782 cksum_key = kctx->initiator_integ; 783 usage = KG_USAGE_INITIATOR_SEAL; 784 } 785 blocksize = crypto_blkcipher_blocksize(cipher); 786 787 788 /* create a segment skipping the header and leaving out the checksum */ 789 xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN, 790 (buf->len - offset - GSS_KRB5_TOK_HDR_LEN - 791 kctx->gk5e->cksumlength)); 792 793 nblocks = (subbuf.len + blocksize - 1) / blocksize; 794 795 cbcbytes = 0; 796 if (nblocks > 2) 797 cbcbytes = (nblocks - 2) * blocksize; 798 799 memset(desc.iv, 0, sizeof(desc.iv)); 800 801 if (cbcbytes) { 802 desc.fragno = 0; 803 desc.fraglen = 0; 804 desc.desc.info = desc.iv; 805 desc.desc.flags = 0; 806 desc.desc.tfm = aux_cipher; 807 808 sg_init_table(desc.frags, 4); 809 810 ret = xdr_process_buf(&subbuf, 0, cbcbytes, decryptor, &desc); 811 if (ret) 812 goto out_err; 813 } 814 815 /* Make sure IV carries forward from any CBC results. */ 816 ret = gss_krb5_cts_crypt(cipher, &subbuf, cbcbytes, desc.iv, NULL, 0); 817 if (ret) 818 goto out_err; 819 820 821 /* Calculate our hmac over the plaintext data */ 822 our_hmac_obj.len = sizeof(our_hmac); 823 our_hmac_obj.data = our_hmac; 824 825 ret = make_checksum_v2(kctx, NULL, 0, &subbuf, 0, 826 cksum_key, usage, &our_hmac_obj); 827 if (ret) 828 goto out_err; 829 830 /* Get the packet's hmac value */ 831 ret = read_bytes_from_xdr_buf(buf, buf->len - kctx->gk5e->cksumlength, 832 pkt_hmac, kctx->gk5e->cksumlength); 833 if (ret) 834 goto out_err; 835 836 if (memcmp(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) { 837 ret = GSS_S_BAD_SIG; 838 goto out_err; 839 } 840 *headskip = kctx->gk5e->conflen; 841 *tailskip = kctx->gk5e->cksumlength; 842out_err: 843 if (ret && ret != GSS_S_BAD_SIG) 844 ret = GSS_S_FAILURE; 845 return ret; 846} 847 848/* 849 * Compute Kseq given the initial session key and the checksum. 850 * Set the key of the given cipher. 851 */ 852int 853krb5_rc4_setup_seq_key(struct krb5_ctx *kctx, struct crypto_blkcipher *cipher, 854 unsigned char *cksum) 855{ 856 struct crypto_hash *hmac; 857 struct hash_desc desc; 858 struct scatterlist sg[1]; 859 u8 Kseq[GSS_KRB5_MAX_KEYLEN]; 860 u32 zeroconstant = 0; 861 int err; 862 863 dprintk("%s: entered\n", __func__); 864 865 hmac = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC); 866 if (IS_ERR(hmac)) { 867 dprintk("%s: error %ld, allocating hash '%s'\n", 868 __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name); 869 return PTR_ERR(hmac); 870 } 871 872 desc.tfm = hmac; 873 desc.flags = 0; 874 875 err = crypto_hash_init(&desc); 876 if (err) 877 goto out_err; 878 879 /* Compute intermediate Kseq from session key */ 880 err = crypto_hash_setkey(hmac, kctx->Ksess, kctx->gk5e->keylength); 881 if (err) 882 goto out_err; 883 884 sg_init_table(sg, 1); 885 sg_set_buf(sg, &zeroconstant, 4); 886 887 err = crypto_hash_digest(&desc, sg, 4, Kseq); 888 if (err) 889 goto out_err; 890 891 /* Compute final Kseq from the checksum and intermediate Kseq */ 892 err = crypto_hash_setkey(hmac, Kseq, kctx->gk5e->keylength); 893 if (err) 894 goto out_err; 895 896 sg_set_buf(sg, cksum, 8); 897 898 err = crypto_hash_digest(&desc, sg, 8, Kseq); 899 if (err) 900 goto out_err; 901 902 err = crypto_blkcipher_setkey(cipher, Kseq, kctx->gk5e->keylength); 903 if (err) 904 goto out_err; 905 906 err = 0; 907 908out_err: 909 crypto_free_hash(hmac); 910 dprintk("%s: returning %d\n", __func__, err); 911 return err; 912} 913 914/* 915 * Compute Kcrypt given the initial session key and the plaintext seqnum. 916 * Set the key of cipher kctx->enc. 917 */ 918int 919krb5_rc4_setup_enc_key(struct krb5_ctx *kctx, struct crypto_blkcipher *cipher, 920 s32 seqnum) 921{ 922 struct crypto_hash *hmac; 923 struct hash_desc desc; 924 struct scatterlist sg[1]; 925 u8 Kcrypt[GSS_KRB5_MAX_KEYLEN]; 926 u8 zeroconstant[4] = {0}; 927 u8 seqnumarray[4]; 928 int err, i; 929 930 dprintk("%s: entered, seqnum %u\n", __func__, seqnum); 931 932 hmac = crypto_alloc_hash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC); 933 if (IS_ERR(hmac)) { 934 dprintk("%s: error %ld, allocating hash '%s'\n", 935 __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name); 936 return PTR_ERR(hmac); 937 } 938 939 desc.tfm = hmac; 940 desc.flags = 0; 941 942 err = crypto_hash_init(&desc); 943 if (err) 944 goto out_err; 945 946 /* Compute intermediate Kcrypt from session key */ 947 for (i = 0; i < kctx->gk5e->keylength; i++) 948 Kcrypt[i] = kctx->Ksess[i] ^ 0xf0; 949 950 err = crypto_hash_setkey(hmac, Kcrypt, kctx->gk5e->keylength); 951 if (err) 952 goto out_err; 953 954 sg_init_table(sg, 1); 955 sg_set_buf(sg, zeroconstant, 4); 956 957 err = crypto_hash_digest(&desc, sg, 4, Kcrypt); 958 if (err) 959 goto out_err; 960 961 /* Compute final Kcrypt from the seqnum and intermediate Kcrypt */ 962 err = crypto_hash_setkey(hmac, Kcrypt, kctx->gk5e->keylength); 963 if (err) 964 goto out_err; 965 966 seqnumarray[0] = (unsigned char) ((seqnum >> 24) & 0xff); 967 seqnumarray[1] = (unsigned char) ((seqnum >> 16) & 0xff); 968 seqnumarray[2] = (unsigned char) ((seqnum >> 8) & 0xff); 969 seqnumarray[3] = (unsigned char) ((seqnum >> 0) & 0xff); 970 971 sg_set_buf(sg, seqnumarray, 4); 972 973 err = crypto_hash_digest(&desc, sg, 4, Kcrypt); 974 if (err) 975 goto out_err; 976 977 err = crypto_blkcipher_setkey(cipher, Kcrypt, kctx->gk5e->keylength); 978 if (err) 979 goto out_err; 980 981 err = 0; 982 983out_err: 984 crypto_free_hash(hmac); 985 dprintk("%s: returning %d\n", __func__, err); 986 return err; 987} 988 989