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 if (cryptlen) 275 get_data_to_compute(cipher, pctx, plain, cryptlen); 276 277 out: 278 return err; 279 } 280 281 static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err) 282 { 283 struct aead_request *req = areq->data; 284 struct crypto_aead *aead = crypto_aead_reqtfm(req); 285 struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req); 286 u8 *odata = pctx->odata; 287 288 if (!err) 289 scatterwalk_map_and_copy(odata, req->dst, req->cryptlen, 290 crypto_aead_authsize(aead), 1); 291 aead_request_complete(req, err); 292 } 293 294 static inline int crypto_ccm_check_iv(const u8 *iv) 295 { 296 /* 2 <= L <= 8, so 1 <= L' <= 7. */ 297 if (1 > iv[0] || iv[0] > 7) 298 return -EINVAL; 299 300 return 0; 301 } 302 303 static int crypto_ccm_encrypt(struct aead_request *req) 304 { 305 struct crypto_aead *aead = crypto_aead_reqtfm(req); 306 struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead); 307 struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req); 308 struct ablkcipher_request *abreq = &pctx->abreq; 309 struct scatterlist *dst; 310 unsigned int cryptlen = req->cryptlen; 311 u8 *odata = pctx->odata; 312 u8 *iv = req->iv; 313 int err; 314 315 err = crypto_ccm_check_iv(iv); 316 if (err) 317 return err; 318 319 pctx->flags = aead_request_flags(req); 320 321 err = crypto_ccm_auth(req, req->src, cryptlen); 322 if (err) 323 return err; 324 325 /* Note: rfc 3610 and NIST 800-38C require counter of 326 * zero to encrypt auth tag. 327 */ 328 memset(iv + 15 - iv[0], 0, iv[0] + 1); 329 330 sg_init_table(pctx->src, 2); 331 sg_set_buf(pctx->src, odata, 16); 332 scatterwalk_sg_chain(pctx->src, 2, req->src); 333 334 dst = pctx->src; 335 if (req->src != req->dst) { 336 sg_init_table(pctx->dst, 2); 337 sg_set_buf(pctx->dst, odata, 16); 338 scatterwalk_sg_chain(pctx->dst, 2, req->dst); 339 dst = pctx->dst; 340 } 341 342 ablkcipher_request_set_tfm(abreq, ctx->ctr); 343 ablkcipher_request_set_callback(abreq, pctx->flags, 344 crypto_ccm_encrypt_done, req); 345 ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv); 346 err = crypto_ablkcipher_encrypt(abreq); 347 if (err) 348 return err; 349 350 /* copy authtag to end of dst */ 351 scatterwalk_map_and_copy(odata, req->dst, cryptlen, 352 crypto_aead_authsize(aead), 1); 353 return err; 354 } 355 356 static void crypto_ccm_decrypt_done(struct crypto_async_request *areq, 357 int err) 358 { 359 struct aead_request *req = areq->data; 360 struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req); 361 struct crypto_aead *aead = crypto_aead_reqtfm(req); 362 unsigned int authsize = crypto_aead_authsize(aead); 363 unsigned int cryptlen = req->cryptlen - authsize; 364 365 if (!err) { 366 err = crypto_ccm_auth(req, req->dst, cryptlen); 367 if (!err && crypto_memneq(pctx->auth_tag, pctx->odata, authsize)) 368 err = -EBADMSG; 369 } 370 aead_request_complete(req, err); 371 } 372 373 static int crypto_ccm_decrypt(struct aead_request *req) 374 { 375 struct crypto_aead *aead = crypto_aead_reqtfm(req); 376 struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead); 377 struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req); 378 struct ablkcipher_request *abreq = &pctx->abreq; 379 struct scatterlist *dst; 380 unsigned int authsize = crypto_aead_authsize(aead); 381 unsigned int cryptlen = req->cryptlen; 382 u8 *authtag = pctx->auth_tag; 383 u8 *odata = pctx->odata; 384 u8 *iv = req->iv; 385 int err; 386 387 if (cryptlen < authsize) 388 return -EINVAL; 389 cryptlen -= authsize; 390 391 err = crypto_ccm_check_iv(iv); 392 if (err) 393 return err; 394 395 pctx->flags = aead_request_flags(req); 396 397 scatterwalk_map_and_copy(authtag, req->src, cryptlen, authsize, 0); 398 399 memset(iv + 15 - iv[0], 0, iv[0] + 1); 400 401 sg_init_table(pctx->src, 2); 402 sg_set_buf(pctx->src, authtag, 16); 403 scatterwalk_sg_chain(pctx->src, 2, req->src); 404 405 dst = pctx->src; 406 if (req->src != req->dst) { 407 sg_init_table(pctx->dst, 2); 408 sg_set_buf(pctx->dst, authtag, 16); 409 scatterwalk_sg_chain(pctx->dst, 2, req->dst); 410 dst = pctx->dst; 411 } 412 413 ablkcipher_request_set_tfm(abreq, ctx->ctr); 414 ablkcipher_request_set_callback(abreq, pctx->flags, 415 crypto_ccm_decrypt_done, req); 416 ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv); 417 err = crypto_ablkcipher_decrypt(abreq); 418 if (err) 419 return err; 420 421 err = crypto_ccm_auth(req, req->dst, cryptlen); 422 if (err) 423 return err; 424 425 /* verify */ 426 if (crypto_memneq(authtag, odata, authsize)) 427 return -EBADMSG; 428 429 return err; 430 } 431 432 static int crypto_ccm_init_tfm(struct crypto_tfm *tfm) 433 { 434 struct crypto_instance *inst = (void *)tfm->__crt_alg; 435 struct ccm_instance_ctx *ictx = crypto_instance_ctx(inst); 436 struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm); 437 struct crypto_cipher *cipher; 438 struct crypto_ablkcipher *ctr; 439 unsigned long align; 440 int err; 441 442 cipher = crypto_spawn_cipher(&ictx->cipher); 443 if (IS_ERR(cipher)) 444 return PTR_ERR(cipher); 445 446 ctr = crypto_spawn_skcipher(&ictx->ctr); 447 err = PTR_ERR(ctr); 448 if (IS_ERR(ctr)) 449 goto err_free_cipher; 450 451 ctx->cipher = cipher; 452 ctx->ctr = ctr; 453 454 align = crypto_tfm_alg_alignmask(tfm); 455 align &= ~(crypto_tfm_ctx_alignment() - 1); 456 crypto_aead_set_reqsize(__crypto_aead_cast(tfm), 457 align + sizeof(struct crypto_ccm_req_priv_ctx) + 458 crypto_ablkcipher_reqsize(ctr)); 459 460 return 0; 461 462 err_free_cipher: 463 crypto_free_cipher(cipher); 464 return err; 465 } 466 467 static void crypto_ccm_exit_tfm(struct crypto_tfm *tfm) 468 { 469 struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm); 470 471 crypto_free_cipher(ctx->cipher); 472 crypto_free_ablkcipher(ctx->ctr); 473 } 474 475 static struct crypto_instance *crypto_ccm_alloc_common(struct rtattr **tb, 476 const char *full_name, 477 const char *ctr_name, 478 const char *cipher_name) 479 { 480 struct crypto_attr_type *algt; 481 struct crypto_instance *inst; 482 struct crypto_alg *ctr; 483 struct crypto_alg *cipher; 484 struct ccm_instance_ctx *ictx; 485 int err; 486 487 algt = crypto_get_attr_type(tb); 488 if (IS_ERR(algt)) 489 return ERR_CAST(algt); 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 if (IS_ERR(cipher)) 497 return ERR_CAST(cipher); 498 499 err = -EINVAL; 500 if (cipher->cra_blocksize != 16) 501 goto out_put_cipher; 502 503 inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL); 504 err = -ENOMEM; 505 if (!inst) 506 goto out_put_cipher; 507 508 ictx = crypto_instance_ctx(inst); 509 510 err = crypto_init_spawn(&ictx->cipher, cipher, inst, 511 CRYPTO_ALG_TYPE_MASK); 512 if (err) 513 goto err_free_inst; 514 515 crypto_set_skcipher_spawn(&ictx->ctr, inst); 516 err = crypto_grab_skcipher(&ictx->ctr, ctr_name, 0, 517 crypto_requires_sync(algt->type, 518 algt->mask)); 519 if (err) 520 goto err_drop_cipher; 521 522 ctr = crypto_skcipher_spawn_alg(&ictx->ctr); 523 524 /* Not a stream cipher? */ 525 err = -EINVAL; 526 if (ctr->cra_blocksize != 1) 527 goto err_drop_ctr; 528 529 /* We want the real thing! */ 530 if (ctr->cra_ablkcipher.ivsize != 16) 531 goto err_drop_ctr; 532 533 err = -ENAMETOOLONG; 534 if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, 535 "ccm_base(%s,%s)", ctr->cra_driver_name, 536 cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME) 537 goto err_drop_ctr; 538 539 memcpy(inst->alg.cra_name, full_name, CRYPTO_MAX_ALG_NAME); 540 541 inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD; 542 inst->alg.cra_flags |= ctr->cra_flags & CRYPTO_ALG_ASYNC; 543 inst->alg.cra_priority = cipher->cra_priority + ctr->cra_priority; 544 inst->alg.cra_blocksize = 1; 545 inst->alg.cra_alignmask = cipher->cra_alignmask | ctr->cra_alignmask | 546 (__alignof__(u32) - 1); 547 inst->alg.cra_type = &crypto_aead_type; 548 inst->alg.cra_aead.ivsize = 16; 549 inst->alg.cra_aead.maxauthsize = 16; 550 inst->alg.cra_ctxsize = sizeof(struct crypto_ccm_ctx); 551 inst->alg.cra_init = crypto_ccm_init_tfm; 552 inst->alg.cra_exit = crypto_ccm_exit_tfm; 553 inst->alg.cra_aead.setkey = crypto_ccm_setkey; 554 inst->alg.cra_aead.setauthsize = crypto_ccm_setauthsize; 555 inst->alg.cra_aead.encrypt = crypto_ccm_encrypt; 556 inst->alg.cra_aead.decrypt = crypto_ccm_decrypt; 557 558 out: 559 crypto_mod_put(cipher); 560 return inst; 561 562 err_drop_ctr: 563 crypto_drop_skcipher(&ictx->ctr); 564 err_drop_cipher: 565 crypto_drop_spawn(&ictx->cipher); 566 err_free_inst: 567 kfree(inst); 568 out_put_cipher: 569 inst = ERR_PTR(err); 570 goto out; 571 } 572 573 static struct crypto_instance *crypto_ccm_alloc(struct rtattr **tb) 574 { 575 const char *cipher_name; 576 char ctr_name[CRYPTO_MAX_ALG_NAME]; 577 char full_name[CRYPTO_MAX_ALG_NAME]; 578 579 cipher_name = crypto_attr_alg_name(tb[1]); 580 if (IS_ERR(cipher_name)) 581 return ERR_CAST(cipher_name); 582 583 if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)", 584 cipher_name) >= CRYPTO_MAX_ALG_NAME) 585 return ERR_PTR(-ENAMETOOLONG); 586 587 if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >= 588 CRYPTO_MAX_ALG_NAME) 589 return ERR_PTR(-ENAMETOOLONG); 590 591 return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name); 592 } 593 594 static void crypto_ccm_free(struct crypto_instance *inst) 595 { 596 struct ccm_instance_ctx *ctx = crypto_instance_ctx(inst); 597 598 crypto_drop_spawn(&ctx->cipher); 599 crypto_drop_skcipher(&ctx->ctr); 600 kfree(inst); 601 } 602 603 static struct crypto_template crypto_ccm_tmpl = { 604 .name = "ccm", 605 .alloc = crypto_ccm_alloc, 606 .free = crypto_ccm_free, 607 .module = THIS_MODULE, 608 }; 609 610 static struct crypto_instance *crypto_ccm_base_alloc(struct rtattr **tb) 611 { 612 const char *ctr_name; 613 const char *cipher_name; 614 char full_name[CRYPTO_MAX_ALG_NAME]; 615 616 ctr_name = crypto_attr_alg_name(tb[1]); 617 if (IS_ERR(ctr_name)) 618 return ERR_CAST(ctr_name); 619 620 cipher_name = crypto_attr_alg_name(tb[2]); 621 if (IS_ERR(cipher_name)) 622 return ERR_CAST(cipher_name); 623 624 if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)", 625 ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME) 626 return ERR_PTR(-ENAMETOOLONG); 627 628 return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name); 629 } 630 631 static struct crypto_template crypto_ccm_base_tmpl = { 632 .name = "ccm_base", 633 .alloc = crypto_ccm_base_alloc, 634 .free = crypto_ccm_free, 635 .module = THIS_MODULE, 636 }; 637 638 static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key, 639 unsigned int keylen) 640 { 641 struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent); 642 struct crypto_aead *child = ctx->child; 643 int err; 644 645 if (keylen < 3) 646 return -EINVAL; 647 648 keylen -= 3; 649 memcpy(ctx->nonce, key + keylen, 3); 650 651 crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK); 652 crypto_aead_set_flags(child, crypto_aead_get_flags(parent) & 653 CRYPTO_TFM_REQ_MASK); 654 err = crypto_aead_setkey(child, key, keylen); 655 crypto_aead_set_flags(parent, crypto_aead_get_flags(child) & 656 CRYPTO_TFM_RES_MASK); 657 658 return err; 659 } 660 661 static int crypto_rfc4309_setauthsize(struct crypto_aead *parent, 662 unsigned int authsize) 663 { 664 struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent); 665 666 switch (authsize) { 667 case 8: 668 case 12: 669 case 16: 670 break; 671 default: 672 return -EINVAL; 673 } 674 675 return crypto_aead_setauthsize(ctx->child, authsize); 676 } 677 678 static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req) 679 { 680 struct aead_request *subreq = aead_request_ctx(req); 681 struct crypto_aead *aead = crypto_aead_reqtfm(req); 682 struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead); 683 struct crypto_aead *child = ctx->child; 684 u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child), 685 crypto_aead_alignmask(child) + 1); 686 687 /* L' */ 688 iv[0] = 3; 689 690 memcpy(iv + 1, ctx->nonce, 3); 691 memcpy(iv + 4, req->iv, 8); 692 693 aead_request_set_tfm(subreq, child); 694 aead_request_set_callback(subreq, req->base.flags, req->base.complete, 695 req->base.data); 696 aead_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, iv); 697 aead_request_set_assoc(subreq, req->assoc, req->assoclen); 698 699 return subreq; 700 } 701 702 static int crypto_rfc4309_encrypt(struct aead_request *req) 703 { 704 req = crypto_rfc4309_crypt(req); 705 706 return crypto_aead_encrypt(req); 707 } 708 709 static int crypto_rfc4309_decrypt(struct aead_request *req) 710 { 711 req = crypto_rfc4309_crypt(req); 712 713 return crypto_aead_decrypt(req); 714 } 715 716 static int crypto_rfc4309_init_tfm(struct crypto_tfm *tfm) 717 { 718 struct crypto_instance *inst = (void *)tfm->__crt_alg; 719 struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst); 720 struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm); 721 struct crypto_aead *aead; 722 unsigned long align; 723 724 aead = crypto_spawn_aead(spawn); 725 if (IS_ERR(aead)) 726 return PTR_ERR(aead); 727 728 ctx->child = aead; 729 730 align = crypto_aead_alignmask(aead); 731 align &= ~(crypto_tfm_ctx_alignment() - 1); 732 crypto_aead_set_reqsize(__crypto_aead_cast(tfm), 733 sizeof(struct aead_request) + 734 ALIGN(crypto_aead_reqsize(aead), crypto_tfm_ctx_alignment()) + 735 align + 16); 736 737 return 0; 738 } 739 740 static void crypto_rfc4309_exit_tfm(struct crypto_tfm *tfm) 741 { 742 struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm); 743 744 crypto_free_aead(ctx->child); 745 } 746 747 static struct crypto_instance *crypto_rfc4309_alloc(struct rtattr **tb) 748 { 749 struct crypto_attr_type *algt; 750 struct crypto_instance *inst; 751 struct crypto_aead_spawn *spawn; 752 struct crypto_alg *alg; 753 const char *ccm_name; 754 int err; 755 756 algt = crypto_get_attr_type(tb); 757 if (IS_ERR(algt)) 758 return ERR_CAST(algt); 759 760 if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask) 761 return ERR_PTR(-EINVAL); 762 763 ccm_name = crypto_attr_alg_name(tb[1]); 764 if (IS_ERR(ccm_name)) 765 return ERR_CAST(ccm_name); 766 767 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL); 768 if (!inst) 769 return ERR_PTR(-ENOMEM); 770 771 spawn = crypto_instance_ctx(inst); 772 crypto_set_aead_spawn(spawn, inst); 773 err = crypto_grab_aead(spawn, ccm_name, 0, 774 crypto_requires_sync(algt->type, algt->mask)); 775 if (err) 776 goto out_free_inst; 777 778 alg = crypto_aead_spawn_alg(spawn); 779 780 err = -EINVAL; 781 782 /* We only support 16-byte blocks. */ 783 if (alg->cra_aead.ivsize != 16) 784 goto out_drop_alg; 785 786 /* Not a stream cipher? */ 787 if (alg->cra_blocksize != 1) 788 goto out_drop_alg; 789 790 err = -ENAMETOOLONG; 791 if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, 792 "rfc4309(%s)", alg->cra_name) >= CRYPTO_MAX_ALG_NAME || 793 snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, 794 "rfc4309(%s)", alg->cra_driver_name) >= 795 CRYPTO_MAX_ALG_NAME) 796 goto out_drop_alg; 797 798 inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD; 799 inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC; 800 inst->alg.cra_priority = alg->cra_priority; 801 inst->alg.cra_blocksize = 1; 802 inst->alg.cra_alignmask = alg->cra_alignmask; 803 inst->alg.cra_type = &crypto_nivaead_type; 804 805 inst->alg.cra_aead.ivsize = 8; 806 inst->alg.cra_aead.maxauthsize = 16; 807 808 inst->alg.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx); 809 810 inst->alg.cra_init = crypto_rfc4309_init_tfm; 811 inst->alg.cra_exit = crypto_rfc4309_exit_tfm; 812 813 inst->alg.cra_aead.setkey = crypto_rfc4309_setkey; 814 inst->alg.cra_aead.setauthsize = crypto_rfc4309_setauthsize; 815 inst->alg.cra_aead.encrypt = crypto_rfc4309_encrypt; 816 inst->alg.cra_aead.decrypt = crypto_rfc4309_decrypt; 817 818 inst->alg.cra_aead.geniv = "seqiv"; 819 820 out: 821 return inst; 822 823 out_drop_alg: 824 crypto_drop_aead(spawn); 825 out_free_inst: 826 kfree(inst); 827 inst = ERR_PTR(err); 828 goto out; 829 } 830 831 static void crypto_rfc4309_free(struct crypto_instance *inst) 832 { 833 crypto_drop_spawn(crypto_instance_ctx(inst)); 834 kfree(inst); 835 } 836 837 static struct crypto_template crypto_rfc4309_tmpl = { 838 .name = "rfc4309", 839 .alloc = crypto_rfc4309_alloc, 840 .free = crypto_rfc4309_free, 841 .module = THIS_MODULE, 842 }; 843 844 static int __init crypto_ccm_module_init(void) 845 { 846 int err; 847 848 err = crypto_register_template(&crypto_ccm_base_tmpl); 849 if (err) 850 goto out; 851 852 err = crypto_register_template(&crypto_ccm_tmpl); 853 if (err) 854 goto out_undo_base; 855 856 err = crypto_register_template(&crypto_rfc4309_tmpl); 857 if (err) 858 goto out_undo_ccm; 859 860 out: 861 return err; 862 863 out_undo_ccm: 864 crypto_unregister_template(&crypto_ccm_tmpl); 865 out_undo_base: 866 crypto_unregister_template(&crypto_ccm_base_tmpl); 867 goto out; 868 } 869 870 static void __exit crypto_ccm_module_exit(void) 871 { 872 crypto_unregister_template(&crypto_rfc4309_tmpl); 873 crypto_unregister_template(&crypto_ccm_tmpl); 874 crypto_unregister_template(&crypto_ccm_base_tmpl); 875 } 876 877 module_init(crypto_ccm_module_init); 878 module_exit(crypto_ccm_module_exit); 879 880 MODULE_LICENSE("GPL"); 881 MODULE_DESCRIPTION("Counter with CBC MAC"); 882 MODULE_ALIAS_CRYPTO("ccm_base"); 883 MODULE_ALIAS_CRYPTO("rfc4309"); 884 MODULE_ALIAS_CRYPTO("ccm"); 885