crypto/ccm.c

   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         if (IS_ERR(algt))
 488                 return ERR_CAST(algt);
 489
 490         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 491                 return ERR_PTR(-EINVAL);
 492
 493         cipher = crypto_alg_mod_lookup(cipher_name,  CRYPTO_ALG_TYPE_CIPHER,
 494                                        CRYPTO_ALG_TYPE_MASK);
 495         if (IS_ERR(cipher))
 496                 return ERR_CAST(cipher);
 497
 498         err = -EINVAL;
 499         if (cipher->cra_blocksize != 16)
 500                 goto out_put_cipher;
 501
 502         inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
 503         err = -ENOMEM;
 504         if (!inst)
 505                 goto out_put_cipher;
 506
 507         ictx = crypto_instance_ctx(inst);
 508
 509         err = crypto_init_spawn(&ictx->cipher, cipher, inst,
 510                                 CRYPTO_ALG_TYPE_MASK);
 511         if (err)
 512                 goto err_free_inst;
 513
 514         crypto_set_skcipher_spawn(&ictx->ctr, inst);
 515         err = crypto_grab_skcipher(&ictx->ctr, ctr_name, 0,
 516                                    crypto_requires_sync(algt->type,
 517                                                         algt->mask));
 518         if (err)
 519                 goto err_drop_cipher;
 520
 521         ctr = crypto_skcipher_spawn_alg(&ictx->ctr);
 522
 523         /* Not a stream cipher? */
 524         err = -EINVAL;
 525         if (ctr->cra_blocksize != 1)
 526                 goto err_drop_ctr;
 527
 528         /* We want the real thing! */
 529         if (ctr->cra_ablkcipher.ivsize != 16)
 530                 goto err_drop_ctr;
 531
 532         err = -ENAMETOOLONG;
 533         if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 534                      "ccm_base(%s,%s)", ctr->cra_driver_name,
 535                      cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 536                 goto err_drop_ctr;
 537
 538         memcpy(inst->alg.cra_name, full_name, CRYPTO_MAX_ALG_NAME);
 539
 540         inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
 541         inst->alg.cra_flags |= ctr->cra_flags & CRYPTO_ALG_ASYNC;
 542         inst->alg.cra_priority = cipher->cra_priority + ctr->cra_priority;
 543         inst->alg.cra_blocksize = 1;
 544         inst->alg.cra_alignmask = cipher->cra_alignmask | ctr->cra_alignmask |
 545                                   (__alignof__(u32) - 1);
 546         inst->alg.cra_type = &crypto_aead_type;
 547         inst->alg.cra_aead.ivsize = 16;
 548         inst->alg.cra_aead.maxauthsize = 16;
 549         inst->alg.cra_ctxsize = sizeof(struct crypto_ccm_ctx);
 550         inst->alg.cra_init = crypto_ccm_init_tfm;
 551         inst->alg.cra_exit = crypto_ccm_exit_tfm;
 552         inst->alg.cra_aead.setkey = crypto_ccm_setkey;
 553         inst->alg.cra_aead.setauthsize = crypto_ccm_setauthsize;
 554         inst->alg.cra_aead.encrypt = crypto_ccm_encrypt;
 555         inst->alg.cra_aead.decrypt = crypto_ccm_decrypt;
 556
 557 out:
 558         crypto_mod_put(cipher);
 559         return inst;
 560
 561 err_drop_ctr:
 562         crypto_drop_skcipher(&ictx->ctr);
 563 err_drop_cipher:
 564         crypto_drop_spawn(&ictx->cipher);
 565 err_free_inst:
 566         kfree(inst);
 567 out_put_cipher:
 568         inst = ERR_PTR(err);
 569         goto out;
 570 }
 571
 572 static struct crypto_instance *crypto_ccm_alloc(struct rtattr **tb)
 573 {
 574         const char *cipher_name;
 575         char ctr_name[CRYPTO_MAX_ALG_NAME];
 576         char full_name[CRYPTO_MAX_ALG_NAME];
 577
 578         cipher_name = crypto_attr_alg_name(tb[1]);
 579         if (IS_ERR(cipher_name))
 580                 return ERR_CAST(cipher_name);
 581
 582         if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
 583                      cipher_name) >= CRYPTO_MAX_ALG_NAME)
 584                 return ERR_PTR(-ENAMETOOLONG);
 585
 586         if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >=
 587             CRYPTO_MAX_ALG_NAME)
 588                 return ERR_PTR(-ENAMETOOLONG);
 589
 590         return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
 591 }
 592
 593 static void crypto_ccm_free(struct crypto_instance *inst)
 594 {
 595         struct ccm_instance_ctx *ctx = crypto_instance_ctx(inst);
 596
 597         crypto_drop_spawn(&ctx->cipher);
 598         crypto_drop_skcipher(&ctx->ctr);
 599         kfree(inst);
 600 }
 601
 602 static struct crypto_template crypto_ccm_tmpl = {
 603         .name = "ccm",
 604         .alloc = crypto_ccm_alloc,
 605         .free = crypto_ccm_free,
 606         .module = THIS_MODULE,
 607 };
 608
 609 static struct crypto_instance *crypto_ccm_base_alloc(struct rtattr **tb)
 610 {
 611         const char *ctr_name;
 612         const char *cipher_name;
 613         char full_name[CRYPTO_MAX_ALG_NAME];
 614
 615         ctr_name = crypto_attr_alg_name(tb[1]);
 616         if (IS_ERR(ctr_name))
 617                 return ERR_CAST(ctr_name);
 618
 619         cipher_name = crypto_attr_alg_name(tb[2]);
 620         if (IS_ERR(cipher_name))
 621                 return ERR_CAST(cipher_name);
 622
 623         if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)",
 624                      ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME)
 625                 return ERR_PTR(-ENAMETOOLONG);
 626
 627         return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
 628 }
 629
 630 static struct crypto_template crypto_ccm_base_tmpl = {
 631         .name = "ccm_base",
 632         .alloc = crypto_ccm_base_alloc,
 633         .free = crypto_ccm_free,
 634         .module = THIS_MODULE,
 635 };
 636
 637 static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
 638                                  unsigned int keylen)
 639 {
 640         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
 641         struct crypto_aead *child = ctx->child;
 642         int err;
 643
 644         if (keylen < 3)
 645                 return -EINVAL;
 646
 647         keylen -= 3;
 648         memcpy(ctx->nonce, key + keylen, 3);
 649
 650         crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 651         crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
 652                                      CRYPTO_TFM_REQ_MASK);
 653         err = crypto_aead_setkey(child, key, keylen);
 654         crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
 655                                       CRYPTO_TFM_RES_MASK);
 656
 657         return err;
 658 }
 659
 660 static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
 661                                       unsigned int authsize)
 662 {
 663         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
 664
 665         switch (authsize) {
 666         case 8:
 667         case 12:
 668         case 16:
 669                 break;
 670         default:
 671                 return -EINVAL;
 672         }
 673
 674         return crypto_aead_setauthsize(ctx->child, authsize);
 675 }
 676
 677 static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
 678 {
 679         struct aead_request *subreq = aead_request_ctx(req);
 680         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 681         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
 682         struct crypto_aead *child = ctx->child;
 683         u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
 684                            crypto_aead_alignmask(child) + 1);
 685
 686         /* L' */
 687         iv[0] = 3;
 688
 689         memcpy(iv + 1, ctx->nonce, 3);
 690         memcpy(iv + 4, req->iv, 8);
 691
 692         aead_request_set_tfm(subreq, child);
 693         aead_request_set_callback(subreq, req->base.flags, req->base.complete,
 694                                   req->base.data);
 695         aead_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, iv);
 696         aead_request_set_assoc(subreq, req->assoc, req->assoclen);
 697
 698         return subreq;
 699 }
 700
 701 static int crypto_rfc4309_encrypt(struct aead_request *req)
 702 {
 703         req = crypto_rfc4309_crypt(req);
 704
 705         return crypto_aead_encrypt(req);
 706 }
 707
 708 static int crypto_rfc4309_decrypt(struct aead_request *req)
 709 {
 710         req = crypto_rfc4309_crypt(req);
 711
 712         return crypto_aead_decrypt(req);
 713 }
 714
 715 static int crypto_rfc4309_init_tfm(struct crypto_tfm *tfm)
 716 {
 717         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 718         struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst);
 719         struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
 720         struct crypto_aead *aead;
 721         unsigned long align;
 722
 723         aead = crypto_spawn_aead(spawn);
 724         if (IS_ERR(aead))
 725                 return PTR_ERR(aead);
 726
 727         ctx->child = aead;
 728
 729         align = crypto_aead_alignmask(aead);
 730         align &= ~(crypto_tfm_ctx_alignment() - 1);
 731         tfm->crt_aead.reqsize = sizeof(struct aead_request) +
 732                                 ALIGN(crypto_aead_reqsize(aead),
 733                                       crypto_tfm_ctx_alignment()) +
 734                                 align + 16;
 735
 736         return 0;
 737 }
 738
 739 static void crypto_rfc4309_exit_tfm(struct crypto_tfm *tfm)
 740 {
 741         struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
 742
 743         crypto_free_aead(ctx->child);
 744 }
 745
 746 static struct crypto_instance *crypto_rfc4309_alloc(struct rtattr **tb)
 747 {
 748         struct crypto_attr_type *algt;
 749         struct crypto_instance *inst;
 750         struct crypto_aead_spawn *spawn;
 751         struct crypto_alg *alg;
 752         const char *ccm_name;
 753         int err;
 754
 755         algt = crypto_get_attr_type(tb);
 756         if (IS_ERR(algt))
 757                 return ERR_CAST(algt);
 758
 759         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 760                 return ERR_PTR(-EINVAL);
 761
 762         ccm_name = crypto_attr_alg_name(tb[1]);
 763         if (IS_ERR(ccm_name))
 764                 return ERR_CAST(ccm_name);
 765
 766         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 767         if (!inst)
 768                 return ERR_PTR(-ENOMEM);
 769
 770         spawn = crypto_instance_ctx(inst);
 771         crypto_set_aead_spawn(spawn, inst);
 772         err = crypto_grab_aead(spawn, ccm_name, 0,
 773                                crypto_requires_sync(algt->type, algt->mask));
 774         if (err)
 775                 goto out_free_inst;
 776
 777         alg = crypto_aead_spawn_alg(spawn);
 778
 779         err = -EINVAL;
 780
 781         /* We only support 16-byte blocks. */
 782         if (alg->cra_aead.ivsize != 16)
 783                 goto out_drop_alg;
 784
 785         /* Not a stream cipher? */
 786         if (alg->cra_blocksize != 1)
 787                 goto out_drop_alg;
 788
 789         err = -ENAMETOOLONG;
 790         if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
 791                      "rfc4309(%s)", alg->cra_name) >= CRYPTO_MAX_ALG_NAME ||
 792             snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 793                      "rfc4309(%s)", alg->cra_driver_name) >=
 794             CRYPTO_MAX_ALG_NAME)
 795                 goto out_drop_alg;
 796
 797         inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
 798         inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
 799         inst->alg.cra_priority = alg->cra_priority;
 800         inst->alg.cra_blocksize = 1;
 801         inst->alg.cra_alignmask = alg->cra_alignmask;
 802         inst->alg.cra_type = &crypto_nivaead_type;
 803
 804         inst->alg.cra_aead.ivsize = 8;
 805         inst->alg.cra_aead.maxauthsize = 16;
 806
 807         inst->alg.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);
 808
 809         inst->alg.cra_init = crypto_rfc4309_init_tfm;
 810         inst->alg.cra_exit = crypto_rfc4309_exit_tfm;
 811
 812         inst->alg.cra_aead.setkey = crypto_rfc4309_setkey;
 813         inst->alg.cra_aead.setauthsize = crypto_rfc4309_setauthsize;
 814         inst->alg.cra_aead.encrypt = crypto_rfc4309_encrypt;
 815         inst->alg.cra_aead.decrypt = crypto_rfc4309_decrypt;
 816
 817         inst->alg.cra_aead.geniv = "seqiv";
 818
 819 out:
 820         return inst;
 821
 822 out_drop_alg:
 823         crypto_drop_aead(spawn);
 824 out_free_inst:
 825         kfree(inst);
 826         inst = ERR_PTR(err);
 827         goto out;
 828 }
 829
 830 static void crypto_rfc4309_free(struct crypto_instance *inst)
 831 {
 832         crypto_drop_spawn(crypto_instance_ctx(inst));
 833         kfree(inst);
 834 }
 835
 836 static struct crypto_template crypto_rfc4309_tmpl = {
 837         .name = "rfc4309",
 838         .alloc = crypto_rfc4309_alloc,
 839         .free = crypto_rfc4309_free,
 840         .module = THIS_MODULE,
 841 };
 842
 843 static int __init crypto_ccm_module_init(void)
 844 {
 845         int err;
 846
 847         err = crypto_register_template(&crypto_ccm_base_tmpl);
 848         if (err)
 849                 goto out;
 850
 851         err = crypto_register_template(&crypto_ccm_tmpl);
 852         if (err)
 853                 goto out_undo_base;
 854
 855         err = crypto_register_template(&crypto_rfc4309_tmpl);
 856         if (err)
 857                 goto out_undo_ccm;
 858
 859 out:
 860         return err;
 861
 862 out_undo_ccm:
 863         crypto_unregister_template(&crypto_ccm_tmpl);
 864 out_undo_base:
 865         crypto_unregister_template(&crypto_ccm_base_tmpl);
 866         goto out;
 867 }
 868
 869 static void __exit crypto_ccm_module_exit(void)
 870 {
 871         crypto_unregister_template(&crypto_rfc4309_tmpl);
 872         crypto_unregister_template(&crypto_ccm_tmpl);
 873         crypto_unregister_template(&crypto_ccm_base_tmpl);
 874 }
 875
 876 module_init(crypto_ccm_module_init);
 877 module_exit(crypto_ccm_module_exit);
 878
 879 MODULE_LICENSE("GPL");
 880 MODULE_DESCRIPTION("Counter with CBC MAC");
 881 MODULE_ALIAS("ccm_base");
 882 MODULE_ALIAS("rfc4309");