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, 0);
 220
 221                 compute_mac(tfm, data_src, n, pctx);
 222                 len -= n;
 223
 224                 scatterwalk_unmap(data_src, 0);
 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");