1 /* 2 * CCM: Counter with CBC-MAC 3 * 4 * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com> 5 * 6 * This program is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License as published by the Free 8 * Software Foundation; either version 2 of the License, or (at your option) 9 * any later version. 10 * 11 */ 12 13 #include <crypto/internal/aead.h> 14 #include <crypto/internal/skcipher.h> 15 #include <crypto/scatterwalk.h> 16 #include <linux/err.h> 17 #include <linux/init.h> 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/slab.h> 21 22 #include "internal.h" 23 24 struct ccm_instance_ctx { 25 struct crypto_skcipher_spawn ctr; 26 struct crypto_spawn cipher; 27 }; 28 29 struct crypto_ccm_ctx { 30 struct crypto_cipher *cipher; 31 struct crypto_ablkcipher *ctr; 32 }; 33 34 struct crypto_rfc4309_ctx { 35 struct crypto_aead *child; 36 u8 nonce[3]; 37 }; 38 39 struct crypto_ccm_req_priv_ctx { 40 u8 odata[16]; 41 u8 idata[16]; 42 u8 auth_tag[16]; 43 u32 ilen; 44 u32 flags; 45 struct scatterlist src[2]; 46 struct scatterlist dst[2]; 47 struct ablkcipher_request abreq; 48 }; 49 50 static inline struct crypto_ccm_req_priv_ctx *crypto_ccm_reqctx( 51 struct aead_request *req) 52 { 53 unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req)); 54 55 return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1); 56 } 57 58 static int set_msg_len(u8 *block, unsigned int msglen, int csize) 59 { 60 __be32 data; 61 62 memset(block, 0, csize); 63 block += csize; 64 65 if (csize >= 4) 66 csize = 4; 67 else if (msglen > (1 << (8 * csize))) 68 return -EOVERFLOW; 69 70 data = cpu_to_be32(msglen); 71 memcpy(block - csize, (u8 *)&data + 4 - csize, csize); 72 73 return 0; 74 } 75 76 static int crypto_ccm_setkey(struct crypto_aead *aead, const u8 *key, 77 unsigned int keylen) 78 { 79 struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead); 80 struct crypto_ablkcipher *ctr = ctx->ctr; 81 struct crypto_cipher *tfm = ctx->cipher; 82 int err = 0; 83 84 crypto_ablkcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK); 85 crypto_ablkcipher_set_flags(ctr, crypto_aead_get_flags(aead) & 86 CRYPTO_TFM_REQ_MASK); 87 err = crypto_ablkcipher_setkey(ctr, key, keylen); 88 crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctr) & 89 CRYPTO_TFM_RES_MASK); 90 if (err) 91 goto out; 92 93 crypto_cipher_clear_flags(tfm, CRYPTO_TFM_REQ_MASK); 94 crypto_cipher_set_flags(tfm, crypto_aead_get_flags(aead) & 95 CRYPTO_TFM_REQ_MASK); 96 err = crypto_cipher_setkey(tfm, key, keylen); 97 crypto_aead_set_flags(aead, crypto_cipher_get_flags(tfm) & 98 CRYPTO_TFM_RES_MASK); 99 100 out: 101 return err; 102 } 103 104 static int crypto_ccm_setauthsize(struct crypto_aead *tfm, 105 unsigned int authsize) 106 { 107 switch (authsize) { 108 case 4: 109 case 6: 110 case 8: 111 case 10: 112 case 12: 113 case 14: 114 case 16: 115 break; 116 default: 117 return -EINVAL; 118 } 119 120 return 0; 121 } 122 123 static int format_input(u8 *info, struct aead_request *req, 124 unsigned int cryptlen) 125 { 126 struct crypto_aead *aead = crypto_aead_reqtfm(req); 127 unsigned int lp = req->iv[0]; 128 unsigned int l = lp + 1; 129 unsigned int m; 130 131 m = crypto_aead_authsize(aead); 132 133 memcpy(info, req->iv, 16); 134 135 /* format control info per RFC 3610 and 136 * NIST Special Publication 800-38C 137 */ 138 *info |= (8 * ((m - 2) / 2)); 139 if (req->assoclen) 140 *info |= 64; 141 142 return set_msg_len(info + 16 - l, cryptlen, l); 143 } 144 145 static int format_adata(u8 *adata, unsigned int a) 146 { 147 int len = 0; 148 149 /* add control info for associated data 150 * RFC 3610 and NIST Special Publication 800-38C 151 */ 152 if (a < 65280) { 153 *(__be16 *)adata = cpu_to_be16(a); 154 len = 2; 155 } else { 156 *(__be16 *)adata = cpu_to_be16(0xfffe); 157 *(__be32 *)&adata[2] = cpu_to_be32(a); 158 len = 6; 159 } 160 161 return len; 162 } 163 164 static void compute_mac(struct crypto_cipher *tfm, u8 *data, int n, 165 struct crypto_ccm_req_priv_ctx *pctx) 166 { 167 unsigned int bs = 16; 168 u8 *odata = pctx->odata; 169 u8 *idata = pctx->idata; 170 int datalen, getlen; 171 172 datalen = n; 173 174 /* first time in here, block may be partially filled. */ 175 getlen = bs - pctx->ilen; 176 if (datalen >= getlen) { 177 memcpy(idata + pctx->ilen, data, getlen); 178 crypto_xor(odata, idata, bs); 179 crypto_cipher_encrypt_one(tfm, odata, odata); 180 datalen -= getlen; 181 data += getlen; 182 pctx->ilen = 0; 183 } 184 185 /* now encrypt rest of data */ 186 while (datalen >= bs) { 187 crypto_xor(odata, data, bs); 188 crypto_cipher_encrypt_one(tfm, odata, odata); 189 190 datalen -= bs; 191 data += bs; 192 } 193 194 /* check and see if there's leftover data that wasn't 195 * enough to fill a block. 196 */ 197 if (datalen) { 198 memcpy(idata + pctx->ilen, data, datalen); 199 pctx->ilen += datalen; 200 } 201 } 202 203 static void get_data_to_compute(struct crypto_cipher *tfm, 204 struct crypto_ccm_req_priv_ctx *pctx, 205 struct scatterlist *sg, unsigned int len) 206 { 207 struct scatter_walk walk; 208 u8 *data_src; 209 int n; 210 211 scatterwalk_start(&walk, sg); 212 213 while (len) { 214 n = scatterwalk_clamp(&walk, len); 215 if (!n) { 216 scatterwalk_start(&walk, sg_next(walk.sg)); 217 n = scatterwalk_clamp(&walk, len); 218 } 219 data_src = scatterwalk_map(&walk); 220 221 compute_mac(tfm, data_src, n, pctx); 222 len -= n; 223 224 scatterwalk_unmap(data_src); 225 scatterwalk_advance(&walk, n); 226 scatterwalk_done(&walk, 0, len); 227 if (len) 228 crypto_yield(pctx->flags); 229 } 230 231 /* any leftover needs padding and then encrypted */ 232 if (pctx->ilen) { 233 int padlen; 234 u8 *odata = pctx->odata; 235 u8 *idata = pctx->idata; 236 237 padlen = 16 - pctx->ilen; 238 memset(idata + pctx->ilen, 0, padlen); 239 crypto_xor(odata, idata, 16); 240 crypto_cipher_encrypt_one(tfm, odata, odata); 241 pctx->ilen = 0; 242 } 243 } 244 245 static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain, 246 unsigned int cryptlen) 247 { 248 struct crypto_aead *aead = crypto_aead_reqtfm(req); 249 struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead); 250 struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req); 251 struct crypto_cipher *cipher = ctx->cipher; 252 unsigned int assoclen = req->assoclen; 253 u8 *odata = pctx->odata; 254 u8 *idata = pctx->idata; 255 int err; 256 257 /* format control data for input */ 258 err = format_input(odata, req, cryptlen); 259 if (err) 260 goto out; 261 262 /* encrypt first block to use as start in computing mac */ 263 crypto_cipher_encrypt_one(cipher, odata, odata); 264 265 /* format associated data and compute into mac */ 266 if (assoclen) { 267 pctx->ilen = format_adata(idata, assoclen); 268 get_data_to_compute(cipher, pctx, req->assoc, req->assoclen); 269 } else { 270 pctx->ilen = 0; 271 } 272 273 /* compute plaintext into mac */ 274 get_data_to_compute(cipher, pctx, plain, cryptlen); 275 276 out: 277 return err; 278 } 279 280 static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err) 281 { 282 struct aead_request *req = areq->data; 283 struct crypto_aead *aead = crypto_aead_reqtfm(req); 284 struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req); 285 u8 *odata = pctx->odata; 286 287 if (!err) 288 scatterwalk_map_and_copy(odata, req->dst, req->cryptlen, 289 crypto_aead_authsize(aead), 1); 290 aead_request_complete(req, err); 291 } 292 293 static inline int crypto_ccm_check_iv(const u8 *iv) 294 { 295 /* 2 <= L <= 8, so 1 <= L' <= 7. */ 296 if (1 > iv[0] || iv[0] > 7) 297 return -EINVAL; 298 299 return 0; 300 } 301 302 static int crypto_ccm_encrypt(struct aead_request *req) 303 { 304 struct crypto_aead *aead = crypto_aead_reqtfm(req); 305 struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead); 306 struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req); 307 struct ablkcipher_request *abreq = &pctx->abreq; 308 struct scatterlist *dst; 309 unsigned int cryptlen = req->cryptlen; 310 u8 *odata = pctx->odata; 311 u8 *iv = req->iv; 312 int err; 313 314 err = crypto_ccm_check_iv(iv); 315 if (err) 316 return err; 317 318 pctx->flags = aead_request_flags(req); 319 320 err = crypto_ccm_auth(req, req->src, cryptlen); 321 if (err) 322 return err; 323 324 /* Note: rfc 3610 and NIST 800-38C require counter of 325 * zero to encrypt auth tag. 326 */ 327 memset(iv + 15 - iv[0], 0, iv[0] + 1); 328 329 sg_init_table(pctx->src, 2); 330 sg_set_buf(pctx->src, odata, 16); 331 scatterwalk_sg_chain(pctx->src, 2, req->src); 332 333 dst = pctx->src; 334 if (req->src != req->dst) { 335 sg_init_table(pctx->dst, 2); 336 sg_set_buf(pctx->dst, odata, 16); 337 scatterwalk_sg_chain(pctx->dst, 2, req->dst); 338 dst = pctx->dst; 339 } 340 341 ablkcipher_request_set_tfm(abreq, ctx->ctr); 342 ablkcipher_request_set_callback(abreq, pctx->flags, 343 crypto_ccm_encrypt_done, req); 344 ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv); 345 err = crypto_ablkcipher_encrypt(abreq); 346 if (err) 347 return err; 348 349 /* copy authtag to end of dst */ 350 scatterwalk_map_and_copy(odata, req->dst, cryptlen, 351 crypto_aead_authsize(aead), 1); 352 return err; 353 } 354 355 static void crypto_ccm_decrypt_done(struct crypto_async_request *areq, 356 int err) 357 { 358 struct aead_request *req = areq->data; 359 struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req); 360 struct crypto_aead *aead = crypto_aead_reqtfm(req); 361 unsigned int authsize = crypto_aead_authsize(aead); 362 unsigned int cryptlen = req->cryptlen - authsize; 363 364 if (!err) { 365 err = crypto_ccm_auth(req, req->dst, cryptlen); 366 if (!err && memcmp(pctx->auth_tag, pctx->odata, authsize)) 367 err = -EBADMSG; 368 } 369 aead_request_complete(req, err); 370 } 371 372 static int crypto_ccm_decrypt(struct aead_request *req) 373 { 374 struct crypto_aead *aead = crypto_aead_reqtfm(req); 375 struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead); 376 struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req); 377 struct ablkcipher_request *abreq = &pctx->abreq; 378 struct scatterlist *dst; 379 unsigned int authsize = crypto_aead_authsize(aead); 380 unsigned int cryptlen = req->cryptlen; 381 u8 *authtag = pctx->auth_tag; 382 u8 *odata = pctx->odata; 383 u8 *iv = req->iv; 384 int err; 385 386 if (cryptlen < authsize) 387 return -EINVAL; 388 cryptlen -= authsize; 389 390 err = crypto_ccm_check_iv(iv); 391 if (err) 392 return err; 393 394 pctx->flags = aead_request_flags(req); 395 396 scatterwalk_map_and_copy(authtag, req->src, cryptlen, authsize, 0); 397 398 memset(iv + 15 - iv[0], 0, iv[0] + 1); 399 400 sg_init_table(pctx->src, 2); 401 sg_set_buf(pctx->src, authtag, 16); 402 scatterwalk_sg_chain(pctx->src, 2, req->src); 403 404 dst = pctx->src; 405 if (req->src != req->dst) { 406 sg_init_table(pctx->dst, 2); 407 sg_set_buf(pctx->dst, authtag, 16); 408 scatterwalk_sg_chain(pctx->dst, 2, req->dst); 409 dst = pctx->dst; 410 } 411 412 ablkcipher_request_set_tfm(abreq, ctx->ctr); 413 ablkcipher_request_set_callback(abreq, pctx->flags, 414 crypto_ccm_decrypt_done, req); 415 ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv); 416 err = crypto_ablkcipher_decrypt(abreq); 417 if (err) 418 return err; 419 420 err = crypto_ccm_auth(req, req->dst, cryptlen); 421 if (err) 422 return err; 423 424 /* verify */ 425 if (memcmp(authtag, odata, authsize)) 426 return -EBADMSG; 427 428 return err; 429 } 430 431 static int crypto_ccm_init_tfm(struct crypto_tfm *tfm) 432 { 433 struct crypto_instance *inst = (void *)tfm->__crt_alg; 434 struct ccm_instance_ctx *ictx = crypto_instance_ctx(inst); 435 struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm); 436 struct crypto_cipher *cipher; 437 struct crypto_ablkcipher *ctr; 438 unsigned long align; 439 int err; 440 441 cipher = crypto_spawn_cipher(&ictx->cipher); 442 if (IS_ERR(cipher)) 443 return PTR_ERR(cipher); 444 445 ctr = crypto_spawn_skcipher(&ictx->ctr); 446 err = PTR_ERR(ctr); 447 if (IS_ERR(ctr)) 448 goto err_free_cipher; 449 450 ctx->cipher = cipher; 451 ctx->ctr = ctr; 452 453 align = crypto_tfm_alg_alignmask(tfm); 454 align &= ~(crypto_tfm_ctx_alignment() - 1); 455 tfm->crt_aead.reqsize = align + 456 sizeof(struct crypto_ccm_req_priv_ctx) + 457 crypto_ablkcipher_reqsize(ctr); 458 459 return 0; 460 461 err_free_cipher: 462 crypto_free_cipher(cipher); 463 return err; 464 } 465 466 static void crypto_ccm_exit_tfm(struct crypto_tfm *tfm) 467 { 468 struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm); 469 470 crypto_free_cipher(ctx->cipher); 471 crypto_free_ablkcipher(ctx->ctr); 472 } 473 474 static struct crypto_instance *crypto_ccm_alloc_common(struct rtattr **tb, 475 const char *full_name, 476 const char *ctr_name, 477 const char *cipher_name) 478 { 479 struct crypto_attr_type *algt; 480 struct crypto_instance *inst; 481 struct crypto_alg *ctr; 482 struct crypto_alg *cipher; 483 struct ccm_instance_ctx *ictx; 484 int err; 485 486 algt = crypto_get_attr_type(tb); 487 err = PTR_ERR(algt); 488 if (IS_ERR(algt)) 489 return ERR_PTR(err); 490 491 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) 492 return ERR_PTR(-EINVAL); 493 494 cipher = crypto_alg_mod_lookup(cipher_name, CRYPTO_ALG_TYPE_CIPHER, 495 CRYPTO_ALG_TYPE_MASK); 496 err = PTR_ERR(cipher); 497 if (IS_ERR(cipher)) 498 return ERR_PTR(err); 499 500 err = -EINVAL; 501 if (cipher->cra_blocksize != 16) 502 goto out_put_cipher; 503 504 inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL); 505 err = -ENOMEM; 506 if (!inst) 507 goto out_put_cipher; 508 509 ictx = crypto_instance_ctx(inst); 510 511 err = crypto_init_spawn(&ictx->cipher, cipher, inst, 512 CRYPTO_ALG_TYPE_MASK); 513 if (err) 514 goto err_free_inst; 515 516 crypto_set_skcipher_spawn(&ictx->ctr, inst); 517 err = crypto_grab_skcipher(&ictx->ctr, ctr_name, 0, 518 crypto_requires_sync(algt->type, 519 algt->mask)); 520 if (err) 521 goto err_drop_cipher; 522 523 ctr = crypto_skcipher_spawn_alg(&ictx->ctr); 524 525 /* Not a stream cipher? */ 526 err = -EINVAL; 527 if (ctr->cra_blocksize != 1) 528 goto err_drop_ctr; 529 530 /* We want the real thing! */ 531 if (ctr->cra_ablkcipher.ivsize != 16) 532 goto err_drop_ctr; 533 534 err = -ENAMETOOLONG; 535 if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, 536 "ccm_base(%s,%s)", ctr->cra_driver_name, 537 cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 538 goto err_drop_ctr; 539 540 memcpy(inst->alg.cra_name, full_name, CRYPTO_MAX_ALG_NAME); 541 542 inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD; 543 inst->alg.cra_flags |= ctr->cra_flags & CRYPTO_ALG_ASYNC; 544 inst->alg.cra_priority = cipher->cra_priority + ctr->cra_priority; 545 inst->alg.cra_blocksize = 1; 546 inst->alg.cra_alignmask = cipher->cra_alignmask | ctr->cra_alignmask | 547 (__alignof__(u32) - 1); 548 inst->alg.cra_type = &crypto_aead_type; 549 inst->alg.cra_aead.ivsize = 16; 550 inst->alg.cra_aead.maxauthsize = 16; 551 inst->alg.cra_ctxsize = sizeof(struct crypto_ccm_ctx); 552 inst->alg.cra_init = crypto_ccm_init_tfm; 553 inst->alg.cra_exit = crypto_ccm_exit_tfm; 554 inst->alg.cra_aead.setkey = crypto_ccm_setkey; 555 inst->alg.cra_aead.setauthsize = crypto_ccm_setauthsize; 556 inst->alg.cra_aead.encrypt = crypto_ccm_encrypt; 557 inst->alg.cra_aead.decrypt = crypto_ccm_decrypt; 558 559 out: 560 crypto_mod_put(cipher); 561 return inst; 562 563 err_drop_ctr: 564 crypto_drop_skcipher(&ictx->ctr); 565 err_drop_cipher: 566 crypto_drop_spawn(&ictx->cipher); 567 err_free_inst: 568 kfree(inst); 569 out_put_cipher: 570 inst = ERR_PTR(err); 571 goto out; 572 } 573 574 static struct crypto_instance *crypto_ccm_alloc(struct rtattr **tb) 575 { 576 int err; 577 const char *cipher_name; 578 char ctr_name[CRYPTO_MAX_ALG_NAME]; 579 char full_name[CRYPTO_MAX_ALG_NAME]; 580 581 cipher_name = crypto_attr_alg_name(tb[1]); 582 err = PTR_ERR(cipher_name); 583 if (IS_ERR(cipher_name)) 584 return ERR_PTR(err); 585 586 if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)", 587 cipher_name) >= CRYPTO_MAX_ALG_NAME) 588 return ERR_PTR(-ENAMETOOLONG); 589 590 if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >= 591 CRYPTO_MAX_ALG_NAME) 592 return ERR_PTR(-ENAMETOOLONG); 593 594 return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name); 595 } 596 597 static void crypto_ccm_free(struct crypto_instance *inst) 598 { 599 struct ccm_instance_ctx *ctx = crypto_instance_ctx(inst); 600 601 crypto_drop_spawn(&ctx->cipher); 602 crypto_drop_skcipher(&ctx->ctr); 603 kfree(inst); 604 } 605 606 static struct crypto_template crypto_ccm_tmpl = { 607 .name = "ccm", 608 .alloc = crypto_ccm_alloc, 609 .free = crypto_ccm_free, 610 .module = THIS_MODULE, 611 }; 612 613 static struct crypto_instance *crypto_ccm_base_alloc(struct rtattr **tb) 614 { 615 int err; 616 const char *ctr_name; 617 const char *cipher_name; 618 char full_name[CRYPTO_MAX_ALG_NAME]; 619 620 ctr_name = crypto_attr_alg_name(tb[1]); 621 err = PTR_ERR(ctr_name); 622 if (IS_ERR(ctr_name)) 623 return ERR_PTR(err); 624 625 cipher_name = crypto_attr_alg_name(tb[2]); 626 err = PTR_ERR(cipher_name); 627 if (IS_ERR(cipher_name)) 628 return ERR_PTR(err); 629 630 if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)", 631 ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME) 632 return ERR_PTR(-ENAMETOOLONG); 633 634 return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name); 635 } 636 637 static struct crypto_template crypto_ccm_base_tmpl = { 638 .name = "ccm_base", 639 .alloc = crypto_ccm_base_alloc, 640 .free = crypto_ccm_free, 641 .module = THIS_MODULE, 642 }; 643 644 static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key, 645 unsigned int keylen) 646 { 647 struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent); 648 struct crypto_aead *child = ctx->child; 649 int err; 650 651 if (keylen < 3) 652 return -EINVAL; 653 654 keylen -= 3; 655 memcpy(ctx->nonce, key + keylen, 3); 656 657 crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK); 658 crypto_aead_set_flags(child, crypto_aead_get_flags(parent) & 659 CRYPTO_TFM_REQ_MASK); 660 err = crypto_aead_setkey(child, key, keylen); 661 crypto_aead_set_flags(parent, crypto_aead_get_flags(child) & 662 CRYPTO_TFM_RES_MASK); 663 664 return err; 665 } 666 667 static int crypto_rfc4309_setauthsize(struct crypto_aead *parent, 668 unsigned int authsize) 669 { 670 struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent); 671 672 switch (authsize) { 673 case 8: 674 case 12: 675 case 16: 676 break; 677 default: 678 return -EINVAL; 679 } 680 681 return crypto_aead_setauthsize(ctx->child, authsize); 682 } 683 684 static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req) 685 { 686 struct aead_request *subreq = aead_request_ctx(req); 687 struct crypto_aead *aead = crypto_aead_reqtfm(req); 688 struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead); 689 struct crypto_aead *child = ctx->child; 690 u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child), 691 crypto_aead_alignmask(child) + 1); 692 693 /* L' */ 694 iv[0] = 3; 695 696 memcpy(iv + 1, ctx->nonce, 3); 697 memcpy(iv + 4, req->iv, 8); 698 699 aead_request_set_tfm(subreq, child); 700 aead_request_set_callback(subreq, req->base.flags, req->base.complete, 701 req->base.data); 702 aead_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, iv); 703 aead_request_set_assoc(subreq, req->assoc, req->assoclen); 704 705 return subreq; 706 } 707 708 static int crypto_rfc4309_encrypt(struct aead_request *req) 709 { 710 req = crypto_rfc4309_crypt(req); 711 712 return crypto_aead_encrypt(req); 713 } 714 715 static int crypto_rfc4309_decrypt(struct aead_request *req) 716 { 717 req = crypto_rfc4309_crypt(req); 718 719 return crypto_aead_decrypt(req); 720 } 721 722 static int crypto_rfc4309_init_tfm(struct crypto_tfm *tfm) 723 { 724 struct crypto_instance *inst = (void *)tfm->__crt_alg; 725 struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst); 726 struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm); 727 struct crypto_aead *aead; 728 unsigned long align; 729 730 aead = crypto_spawn_aead(spawn); 731 if (IS_ERR(aead)) 732 return PTR_ERR(aead); 733 734 ctx->child = aead; 735 736 align = crypto_aead_alignmask(aead); 737 align &= ~(crypto_tfm_ctx_alignment() - 1); 738 tfm->crt_aead.reqsize = sizeof(struct aead_request) + 739 ALIGN(crypto_aead_reqsize(aead), 740 crypto_tfm_ctx_alignment()) + 741 align + 16; 742 743 return 0; 744 } 745 746 static void crypto_rfc4309_exit_tfm(struct crypto_tfm *tfm) 747 { 748 struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm); 749 750 crypto_free_aead(ctx->child); 751 } 752 753 static struct crypto_instance *crypto_rfc4309_alloc(struct rtattr **tb) 754 { 755 struct crypto_attr_type *algt; 756 struct crypto_instance *inst; 757 struct crypto_aead_spawn *spawn; 758 struct crypto_alg *alg; 759 const char *ccm_name; 760 int err; 761 762 algt = crypto_get_attr_type(tb); 763 err = PTR_ERR(algt); 764 if (IS_ERR(algt)) 765 return ERR_PTR(err); 766 767 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) 768 return ERR_PTR(-EINVAL); 769 770 ccm_name = crypto_attr_alg_name(tb[1]); 771 err = PTR_ERR(ccm_name); 772 if (IS_ERR(ccm_name)) 773 return ERR_PTR(err); 774 775 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL); 776 if (!inst) 777 return ERR_PTR(-ENOMEM); 778 779 spawn = crypto_instance_ctx(inst); 780 crypto_set_aead_spawn(spawn, inst); 781 err = crypto_grab_aead(spawn, ccm_name, 0, 782 crypto_requires_sync(algt->type, algt->mask)); 783 if (err) 784 goto out_free_inst; 785 786 alg = crypto_aead_spawn_alg(spawn); 787 788 err = -EINVAL; 789 790 /* We only support 16-byte blocks. */ 791 if (alg->cra_aead.ivsize != 16) 792 goto out_drop_alg; 793 794 /* Not a stream cipher? */ 795 if (alg->cra_blocksize != 1) 796 goto out_drop_alg; 797 798 err = -ENAMETOOLONG; 799 if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, 800 "rfc4309(%s)", alg->cra_name) >= CRYPTO_MAX_ALG_NAME || 801 snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, 802 "rfc4309(%s)", alg->cra_driver_name) >= 803 CRYPTO_MAX_ALG_NAME) 804 goto out_drop_alg; 805 806 inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD; 807 inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC; 808 inst->alg.cra_priority = alg->cra_priority; 809 inst->alg.cra_blocksize = 1; 810 inst->alg.cra_alignmask = alg->cra_alignmask; 811 inst->alg.cra_type = &crypto_nivaead_type; 812 813 inst->alg.cra_aead.ivsize = 8; 814 inst->alg.cra_aead.maxauthsize = 16; 815 816 inst->alg.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx); 817 818 inst->alg.cra_init = crypto_rfc4309_init_tfm; 819 inst->alg.cra_exit = crypto_rfc4309_exit_tfm; 820 821 inst->alg.cra_aead.setkey = crypto_rfc4309_setkey; 822 inst->alg.cra_aead.setauthsize = crypto_rfc4309_setauthsize; 823 inst->alg.cra_aead.encrypt = crypto_rfc4309_encrypt; 824 inst->alg.cra_aead.decrypt = crypto_rfc4309_decrypt; 825 826 inst->alg.cra_aead.geniv = "seqiv"; 827 828 out: 829 return inst; 830 831 out_drop_alg: 832 crypto_drop_aead(spawn); 833 out_free_inst: 834 kfree(inst); 835 inst = ERR_PTR(err); 836 goto out; 837 } 838 839 static void crypto_rfc4309_free(struct crypto_instance *inst) 840 { 841 crypto_drop_spawn(crypto_instance_ctx(inst)); 842 kfree(inst); 843 } 844 845 static struct crypto_template crypto_rfc4309_tmpl = { 846 .name = "rfc4309", 847 .alloc = crypto_rfc4309_alloc, 848 .free = crypto_rfc4309_free, 849 .module = THIS_MODULE, 850 }; 851 852 static int __init crypto_ccm_module_init(void) 853 { 854 int err; 855 856 err = crypto_register_template(&crypto_ccm_base_tmpl); 857 if (err) 858 goto out; 859 860 err = crypto_register_template(&crypto_ccm_tmpl); 861 if (err) 862 goto out_undo_base; 863 864 err = crypto_register_template(&crypto_rfc4309_tmpl); 865 if (err) 866 goto out_undo_ccm; 867 868 out: 869 return err; 870 871 out_undo_ccm: 872 crypto_unregister_template(&crypto_ccm_tmpl); 873 out_undo_base: 874 crypto_unregister_template(&crypto_ccm_base_tmpl); 875 goto out; 876 } 877 878 static void __exit crypto_ccm_module_exit(void) 879 { 880 crypto_unregister_template(&crypto_rfc4309_tmpl); 881 crypto_unregister_template(&crypto_ccm_tmpl); 882 crypto_unregister_template(&crypto_ccm_base_tmpl); 883 } 884 885 module_init(crypto_ccm_module_init); 886 module_exit(crypto_ccm_module_exit); 887 888 MODULE_LICENSE("GPL"); 889 MODULE_DESCRIPTION("Counter with CBC MAC"); 890 MODULE_ALIAS("ccm_base"); 891 MODULE_ALIAS("rfc4309"); 892