crypto/ccm.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * CCM: Counter with CBC-MAC
   4  *
   5  * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
   6  */
   7
   8 #include <crypto/internal/aead.h>
   9 #include <crypto/internal/hash.h>
  10 #include <crypto/internal/skcipher.h>
  11 #include <crypto/scatterwalk.h>
  12 #include <linux/err.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17
  18 #include "internal.h"
  19
  20 struct ccm_instance_ctx {
  21         struct crypto_skcipher_spawn ctr;
  22         struct crypto_ahash_spawn mac;
  23 };
  24
  25 struct crypto_ccm_ctx {
  26         struct crypto_ahash *mac;
  27         struct crypto_skcipher *ctr;
  28 };
  29
  30 struct crypto_rfc4309_ctx {
  31         struct crypto_aead *child;
  32         u8 nonce[3];
  33 };
  34
  35 struct crypto_rfc4309_req_ctx {
  36         struct scatterlist src[3];
  37         struct scatterlist dst[3];
  38         struct aead_request subreq;
  39 };
  40
  41 struct crypto_ccm_req_priv_ctx {
  42         u8 odata[16];
  43         u8 idata[16];
  44         u8 auth_tag[16];
  45         u32 flags;
  46         struct scatterlist src[3];
  47         struct scatterlist dst[3];
  48         union {
  49                 struct ahash_request ahreq;
  50                 struct skcipher_request skreq;
  51         };
  52 };
  53
  54 struct cbcmac_tfm_ctx {
  55         struct crypto_cipher *child;
  56 };
  57
  58 struct cbcmac_desc_ctx {
  59         unsigned int len;
  60 };
  61
  62 static inline struct crypto_ccm_req_priv_ctx *crypto_ccm_reqctx(
  63         struct aead_request *req)
  64 {
  65         unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));
  66
  67         return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
  68 }
  69
  70 static int set_msg_len(u8 *block, unsigned int msglen, int csize)
  71 {
  72         __be32 data;
  73
  74         memset(block, 0, csize);
  75         block += csize;
  76
  77         if (csize >= 4)
  78                 csize = 4;
  79         else if (msglen > (1 << (8 * csize)))
  80                 return -EOVERFLOW;
  81
  82         data = cpu_to_be32(msglen);
  83         memcpy(block - csize, (u8 *)&data + 4 - csize, csize);
  84
  85         return 0;
  86 }
  87
  88 static int crypto_ccm_setkey(struct crypto_aead *aead, const u8 *key,
  89                              unsigned int keylen)
  90 {
  91         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
  92         struct crypto_skcipher *ctr = ctx->ctr;
  93         struct crypto_ahash *mac = ctx->mac;
  94         int err = 0;
  95
  96         crypto_skcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
  97         crypto_skcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
  98                                        CRYPTO_TFM_REQ_MASK);
  99         err = crypto_skcipher_setkey(ctr, key, keylen);
 100         crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctr) &
 101                               CRYPTO_TFM_RES_MASK);
 102         if (err)
 103                 goto out;
 104
 105         crypto_ahash_clear_flags(mac, CRYPTO_TFM_REQ_MASK);
 106         crypto_ahash_set_flags(mac, crypto_aead_get_flags(aead) &
 107                                     CRYPTO_TFM_REQ_MASK);
 108         err = crypto_ahash_setkey(mac, key, keylen);
 109         crypto_aead_set_flags(aead, crypto_ahash_get_flags(mac) &
 110                               CRYPTO_TFM_RES_MASK);
 111
 112 out:
 113         return err;
 114 }
 115
 116 static int crypto_ccm_setauthsize(struct crypto_aead *tfm,
 117                                   unsigned int authsize)
 118 {
 119         switch (authsize) {
 120         case 4:
 121         case 6:
 122         case 8:
 123         case 10:
 124         case 12:
 125         case 14:
 126         case 16:
 127                 break;
 128         default:
 129                 return -EINVAL;
 130         }
 131
 132         return 0;
 133 }
 134
 135 static int format_input(u8 *info, struct aead_request *req,
 136                         unsigned int cryptlen)
 137 {
 138         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 139         unsigned int lp = req->iv[0];
 140         unsigned int l = lp + 1;
 141         unsigned int m;
 142
 143         m = crypto_aead_authsize(aead);
 144
 145         memcpy(info, req->iv, 16);
 146
 147         /* format control info per RFC 3610 and
 148          * NIST Special Publication 800-38C
 149          */
 150         *info |= (8 * ((m - 2) / 2));
 151         if (req->assoclen)
 152                 *info |= 64;
 153
 154         return set_msg_len(info + 16 - l, cryptlen, l);
 155 }
 156
 157 static int format_adata(u8 *adata, unsigned int a)
 158 {
 159         int len = 0;
 160
 161         /* add control info for associated data
 162          * RFC 3610 and NIST Special Publication 800-38C
 163          */
 164         if (a < 65280) {
 165                 *(__be16 *)adata = cpu_to_be16(a);
 166                 len = 2;
 167         } else  {
 168                 *(__be16 *)adata = cpu_to_be16(0xfffe);
 169                 *(__be32 *)&adata[2] = cpu_to_be32(a);
 170                 len = 6;
 171         }
 172
 173         return len;
 174 }
 175
 176 static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain,
 177                            unsigned int cryptlen)
 178 {
 179         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 180         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 181         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
 182         struct ahash_request *ahreq = &pctx->ahreq;
 183         unsigned int assoclen = req->assoclen;
 184         struct scatterlist sg[3];
 185         u8 *odata = pctx->odata;
 186         u8 *idata = pctx->idata;
 187         int ilen, err;
 188
 189         /* format control data for input */
 190         err = format_input(odata, req, cryptlen);
 191         if (err)
 192                 goto out;
 193
 194         sg_init_table(sg, 3);
 195         sg_set_buf(&sg[0], odata, 16);
 196
 197         /* format associated data and compute into mac */
 198         if (assoclen) {
 199                 ilen = format_adata(idata, assoclen);
 200                 sg_set_buf(&sg[1], idata, ilen);
 201                 sg_chain(sg, 3, req->src);
 202         } else {
 203                 ilen = 0;
 204                 sg_chain(sg, 2, req->src);
 205         }
 206
 207         ahash_request_set_tfm(ahreq, ctx->mac);
 208         ahash_request_set_callback(ahreq, pctx->flags, NULL, NULL);
 209         ahash_request_set_crypt(ahreq, sg, NULL, assoclen + ilen + 16);
 210         err = crypto_ahash_init(ahreq);
 211         if (err)
 212                 goto out;
 213         err = crypto_ahash_update(ahreq);
 214         if (err)
 215                 goto out;
 216
 217         /* we need to pad the MAC input to a round multiple of the block size */
 218         ilen = 16 - (assoclen + ilen) % 16;
 219         if (ilen < 16) {
 220                 memset(idata, 0, ilen);
 221                 sg_init_table(sg, 2);
 222                 sg_set_buf(&sg[0], idata, ilen);
 223                 if (plain)
 224                         sg_chain(sg, 2, plain);
 225                 plain = sg;
 226                 cryptlen += ilen;
 227         }
 228
 229         ahash_request_set_crypt(ahreq, plain, pctx->odata, cryptlen);
 230         err = crypto_ahash_finup(ahreq);
 231 out:
 232         return err;
 233 }
 234
 235 static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err)
 236 {
 237         struct aead_request *req = areq->data;
 238         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 239         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 240         u8 *odata = pctx->odata;
 241
 242         if (!err)
 243                 scatterwalk_map_and_copy(odata, req->dst,
 244                                          req->assoclen + req->cryptlen,
 245                                          crypto_aead_authsize(aead), 1);
 246         aead_request_complete(req, err);
 247 }
 248
 249 static inline int crypto_ccm_check_iv(const u8 *iv)
 250 {
 251         /* 2 <= L <= 8, so 1 <= L' <= 7. */
 252         if (1 > iv[0] || iv[0] > 7)
 253                 return -EINVAL;
 254
 255         return 0;
 256 }
 257
 258 static int crypto_ccm_init_crypt(struct aead_request *req, u8 *tag)
 259 {
 260         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 261         struct scatterlist *sg;
 262         u8 *iv = req->iv;
 263         int err;
 264
 265         err = crypto_ccm_check_iv(iv);
 266         if (err)
 267                 return err;
 268
 269         pctx->flags = aead_request_flags(req);
 270
 271          /* Note: rfc 3610 and NIST 800-38C require counter of
 272          * zero to encrypt auth tag.
 273          */
 274         memset(iv + 15 - iv[0], 0, iv[0] + 1);
 275
 276         sg_init_table(pctx->src, 3);
 277         sg_set_buf(pctx->src, tag, 16);
 278         sg = scatterwalk_ffwd(pctx->src + 1, req->src, req->assoclen);
 279         if (sg != pctx->src + 1)
 280                 sg_chain(pctx->src, 2, sg);
 281
 282         if (req->src != req->dst) {
 283                 sg_init_table(pctx->dst, 3);
 284                 sg_set_buf(pctx->dst, tag, 16);
 285                 sg = scatterwalk_ffwd(pctx->dst + 1, req->dst, req->assoclen);
 286                 if (sg != pctx->dst + 1)
 287                         sg_chain(pctx->dst, 2, sg);
 288         }
 289
 290         return 0;
 291 }
 292
 293 static int crypto_ccm_encrypt(struct aead_request *req)
 294 {
 295         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 296         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
 297         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 298         struct skcipher_request *skreq = &pctx->skreq;
 299         struct scatterlist *dst;
 300         unsigned int cryptlen = req->cryptlen;
 301         u8 *odata = pctx->odata;
 302         u8 *iv = req->iv;
 303         int err;
 304
 305         err = crypto_ccm_init_crypt(req, odata);
 306         if (err)
 307                 return err;
 308
 309         err = crypto_ccm_auth(req, sg_next(pctx->src), cryptlen);
 310         if (err)
 311                 return err;
 312
 313         dst = pctx->src;
 314         if (req->src != req->dst)
 315                 dst = pctx->dst;
 316
 317         skcipher_request_set_tfm(skreq, ctx->ctr);
 318         skcipher_request_set_callback(skreq, pctx->flags,
 319                                       crypto_ccm_encrypt_done, req);
 320         skcipher_request_set_crypt(skreq, pctx->src, dst, cryptlen + 16, iv);
 321         err = crypto_skcipher_encrypt(skreq);
 322         if (err)
 323                 return err;
 324
 325         /* copy authtag to end of dst */
 326         scatterwalk_map_and_copy(odata, sg_next(dst), cryptlen,
 327                                  crypto_aead_authsize(aead), 1);
 328         return err;
 329 }
 330
 331 static void crypto_ccm_decrypt_done(struct crypto_async_request *areq,
 332                                    int err)
 333 {
 334         struct aead_request *req = areq->data;
 335         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 336         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 337         unsigned int authsize = crypto_aead_authsize(aead);
 338         unsigned int cryptlen = req->cryptlen - authsize;
 339         struct scatterlist *dst;
 340
 341         pctx->flags = 0;
 342
 343         dst = sg_next(req->src == req->dst ? pctx->src : pctx->dst);
 344
 345         if (!err) {
 346                 err = crypto_ccm_auth(req, dst, cryptlen);
 347                 if (!err && crypto_memneq(pctx->auth_tag, pctx->odata, authsize))
 348                         err = -EBADMSG;
 349         }
 350         aead_request_complete(req, err);
 351 }
 352
 353 static int crypto_ccm_decrypt(struct aead_request *req)
 354 {
 355         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 356         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
 357         struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 358         struct skcipher_request *skreq = &pctx->skreq;
 359         struct scatterlist *dst;
 360         unsigned int authsize = crypto_aead_authsize(aead);
 361         unsigned int cryptlen = req->cryptlen;
 362         u8 *authtag = pctx->auth_tag;
 363         u8 *odata = pctx->odata;
 364         u8 *iv = pctx->idata;
 365         int err;
 366
 367         cryptlen -= authsize;
 368
 369         err = crypto_ccm_init_crypt(req, authtag);
 370         if (err)
 371                 return err;
 372
 373         scatterwalk_map_and_copy(authtag, sg_next(pctx->src), cryptlen,
 374                                  authsize, 0);
 375
 376         dst = pctx->src;
 377         if (req->src != req->dst)
 378                 dst = pctx->dst;
 379
 380         memcpy(iv, req->iv, 16);
 381
 382         skcipher_request_set_tfm(skreq, ctx->ctr);
 383         skcipher_request_set_callback(skreq, pctx->flags,
 384                                       crypto_ccm_decrypt_done, req);
 385         skcipher_request_set_crypt(skreq, pctx->src, dst, cryptlen + 16, iv);
 386         err = crypto_skcipher_decrypt(skreq);
 387         if (err)
 388                 return err;
 389
 390         err = crypto_ccm_auth(req, sg_next(dst), cryptlen);
 391         if (err)
 392                 return err;
 393
 394         /* verify */
 395         if (crypto_memneq(authtag, odata, authsize))
 396                 return -EBADMSG;
 397
 398         return err;
 399 }
 400
 401 static int crypto_ccm_init_tfm(struct crypto_aead *tfm)
 402 {
 403         struct aead_instance *inst = aead_alg_instance(tfm);
 404         struct ccm_instance_ctx *ictx = aead_instance_ctx(inst);
 405         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(tfm);
 406         struct crypto_ahash *mac;
 407         struct crypto_skcipher *ctr;
 408         unsigned long align;
 409         int err;
 410
 411         mac = crypto_spawn_ahash(&ictx->mac);
 412         if (IS_ERR(mac))
 413                 return PTR_ERR(mac);
 414
 415         ctr = crypto_spawn_skcipher(&ictx->ctr);
 416         err = PTR_ERR(ctr);
 417         if (IS_ERR(ctr))
 418                 goto err_free_mac;
 419
 420         ctx->mac = mac;
 421         ctx->ctr = ctr;
 422
 423         align = crypto_aead_alignmask(tfm);
 424         align &= ~(crypto_tfm_ctx_alignment() - 1);
 425         crypto_aead_set_reqsize(
 426                 tfm,
 427                 align + sizeof(struct crypto_ccm_req_priv_ctx) +
 428                 max(crypto_ahash_reqsize(mac), crypto_skcipher_reqsize(ctr)));
 429
 430         return 0;
 431
 432 err_free_mac:
 433         crypto_free_ahash(mac);
 434         return err;
 435 }
 436
 437 static void crypto_ccm_exit_tfm(struct crypto_aead *tfm)
 438 {
 439         struct crypto_ccm_ctx *ctx = crypto_aead_ctx(tfm);
 440
 441         crypto_free_ahash(ctx->mac);
 442         crypto_free_skcipher(ctx->ctr);
 443 }
 444
 445 static void crypto_ccm_free(struct aead_instance *inst)
 446 {
 447         struct ccm_instance_ctx *ctx = aead_instance_ctx(inst);
 448
 449         crypto_drop_ahash(&ctx->mac);
 450         crypto_drop_skcipher(&ctx->ctr);
 451         kfree(inst);
 452 }
 453
 454 static int crypto_ccm_create_common(struct crypto_template *tmpl,
 455                                     struct rtattr **tb,
 456                                     const char *ctr_name,
 457                                     const char *mac_name)
 458 {
 459         struct crypto_attr_type *algt;
 460         struct aead_instance *inst;
 461         struct skcipher_alg *ctr;
 462         struct crypto_alg *mac_alg;
 463         struct hash_alg_common *mac;
 464         struct ccm_instance_ctx *ictx;
 465         int err;
 466
 467         algt = crypto_get_attr_type(tb);
 468         if (IS_ERR(algt))
 469                 return PTR_ERR(algt);
 470
 471         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 472                 return -EINVAL;
 473
 474         mac_alg = crypto_find_alg(mac_name, &crypto_ahash_type,
 475                                   CRYPTO_ALG_TYPE_HASH,
 476                                   CRYPTO_ALG_TYPE_AHASH_MASK |
 477                                   CRYPTO_ALG_ASYNC);
 478         if (IS_ERR(mac_alg))
 479                 return PTR_ERR(mac_alg);
 480
 481         mac = __crypto_hash_alg_common(mac_alg);
 482         err = -EINVAL;
 483         if (strncmp(mac->base.cra_name, "cbcmac(", 7) != 0 ||
 484             mac->digestsize != 16)
 485                 goto out_put_mac;
 486
 487         inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
 488         err = -ENOMEM;
 489         if (!inst)
 490                 goto out_put_mac;
 491
 492         ictx = aead_instance_ctx(inst);
 493         err = crypto_init_ahash_spawn(&ictx->mac, mac,
 494                                       aead_crypto_instance(inst));
 495         if (err)
 496                 goto err_free_inst;
 497
 498         crypto_set_skcipher_spawn(&ictx->ctr, aead_crypto_instance(inst));
 499         err = crypto_grab_skcipher(&ictx->ctr, ctr_name, 0,
 500                                    crypto_requires_sync(algt->type,
 501                                                         algt->mask));
 502         if (err)
 503                 goto err_drop_mac;
 504
 505         ctr = crypto_spawn_skcipher_alg(&ictx->ctr);
 506
 507         /* The skcipher algorithm must be CTR mode, using 16-byte blocks. */
 508         err = -EINVAL;
 509         if (strncmp(ctr->base.cra_name, "ctr(", 4) != 0 ||
 510             crypto_skcipher_alg_ivsize(ctr) != 16 ||
 511             ctr->base.cra_blocksize != 1)
 512                 goto err_drop_ctr;
 513
 514         /* ctr and cbcmac must use the same underlying block cipher. */
 515         if (strcmp(ctr->base.cra_name + 4, mac->base.cra_name + 7) != 0)
 516                 goto err_drop_ctr;
 517
 518         err = -ENAMETOOLONG;
 519         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 520                      "ccm(%s", ctr->base.cra_name + 4) >= CRYPTO_MAX_ALG_NAME)
 521                 goto err_drop_ctr;
 522
 523         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 524                      "ccm_base(%s,%s)", ctr->base.cra_driver_name,
 525                      mac->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 526                 goto err_drop_ctr;
 527
 528         inst->alg.base.cra_flags = ctr->base.cra_flags & CRYPTO_ALG_ASYNC;
 529         inst->alg.base.cra_priority = (mac->base.cra_priority +
 530                                        ctr->base.cra_priority) / 2;
 531         inst->alg.base.cra_blocksize = 1;
 532         inst->alg.base.cra_alignmask = mac->base.cra_alignmask |
 533                                        ctr->base.cra_alignmask;
 534         inst->alg.ivsize = 16;
 535         inst->alg.chunksize = crypto_skcipher_alg_chunksize(ctr);
 536         inst->alg.maxauthsize = 16;
 537         inst->alg.base.cra_ctxsize = sizeof(struct crypto_ccm_ctx);
 538         inst->alg.init = crypto_ccm_init_tfm;
 539         inst->alg.exit = crypto_ccm_exit_tfm;
 540         inst->alg.setkey = crypto_ccm_setkey;
 541         inst->alg.setauthsize = crypto_ccm_setauthsize;
 542         inst->alg.encrypt = crypto_ccm_encrypt;
 543         inst->alg.decrypt = crypto_ccm_decrypt;
 544
 545         inst->free = crypto_ccm_free;
 546
 547         err = aead_register_instance(tmpl, inst);
 548         if (err)
 549                 goto err_drop_ctr;
 550
 551 out_put_mac:
 552         crypto_mod_put(mac_alg);
 553         return err;
 554
 555 err_drop_ctr:
 556         crypto_drop_skcipher(&ictx->ctr);
 557 err_drop_mac:
 558         crypto_drop_ahash(&ictx->mac);
 559 err_free_inst:
 560         kfree(inst);
 561         goto out_put_mac;
 562 }
 563
 564 static int crypto_ccm_create(struct crypto_template *tmpl, struct rtattr **tb)
 565 {
 566         const char *cipher_name;
 567         char ctr_name[CRYPTO_MAX_ALG_NAME];
 568         char mac_name[CRYPTO_MAX_ALG_NAME];
 569
 570         cipher_name = crypto_attr_alg_name(tb[1]);
 571         if (IS_ERR(cipher_name))
 572                 return PTR_ERR(cipher_name);
 573
 574         if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
 575                      cipher_name) >= CRYPTO_MAX_ALG_NAME)
 576                 return -ENAMETOOLONG;
 577
 578         if (snprintf(mac_name, CRYPTO_MAX_ALG_NAME, "cbcmac(%s)",
 579                      cipher_name) >= CRYPTO_MAX_ALG_NAME)
 580                 return -ENAMETOOLONG;
 581
 582         return crypto_ccm_create_common(tmpl, tb, ctr_name, mac_name);
 583 }
 584
 585 static int crypto_ccm_base_create(struct crypto_template *tmpl,
 586                                   struct rtattr **tb)
 587 {
 588         const char *ctr_name;
 589         const char *mac_name;
 590
 591         ctr_name = crypto_attr_alg_name(tb[1]);
 592         if (IS_ERR(ctr_name))
 593                 return PTR_ERR(ctr_name);
 594
 595         mac_name = crypto_attr_alg_name(tb[2]);
 596         if (IS_ERR(mac_name))
 597                 return PTR_ERR(mac_name);
 598
 599         return crypto_ccm_create_common(tmpl, tb, ctr_name, mac_name);
 600 }
 601
 602 static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
 603                                  unsigned int keylen)
 604 {
 605         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
 606         struct crypto_aead *child = ctx->child;
 607         int err;
 608
 609         if (keylen < 3)
 610                 return -EINVAL;
 611
 612         keylen -= 3;
 613         memcpy(ctx->nonce, key + keylen, 3);
 614
 615         crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 616         crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
 617                                      CRYPTO_TFM_REQ_MASK);
 618         err = crypto_aead_setkey(child, key, keylen);
 619         crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
 620                                       CRYPTO_TFM_RES_MASK);
 621
 622         return err;
 623 }
 624
 625 static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
 626                                       unsigned int authsize)
 627 {
 628         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
 629
 630         switch (authsize) {
 631         case 8:
 632         case 12:
 633         case 16:
 634                 break;
 635         default:
 636                 return -EINVAL;
 637         }
 638
 639         return crypto_aead_setauthsize(ctx->child, authsize);
 640 }
 641
 642 static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
 643 {
 644         struct crypto_rfc4309_req_ctx *rctx = aead_request_ctx(req);
 645         struct aead_request *subreq = &rctx->subreq;
 646         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 647         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
 648         struct crypto_aead *child = ctx->child;
 649         struct scatterlist *sg;
 650         u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
 651                            crypto_aead_alignmask(child) + 1);
 652
 653         /* L' */
 654         iv[0] = 3;
 655
 656         memcpy(iv + 1, ctx->nonce, 3);
 657         memcpy(iv + 4, req->iv, 8);
 658
 659         scatterwalk_map_and_copy(iv + 16, req->src, 0, req->assoclen - 8, 0);
 660
 661         sg_init_table(rctx->src, 3);
 662         sg_set_buf(rctx->src, iv + 16, req->assoclen - 8);
 663         sg = scatterwalk_ffwd(rctx->src + 1, req->src, req->assoclen);
 664         if (sg != rctx->src + 1)
 665                 sg_chain(rctx->src, 2, sg);
 666
 667         if (req->src != req->dst) {
 668                 sg_init_table(rctx->dst, 3);
 669                 sg_set_buf(rctx->dst, iv + 16, req->assoclen - 8);
 670                 sg = scatterwalk_ffwd(rctx->dst + 1, req->dst, req->assoclen);
 671                 if (sg != rctx->dst + 1)
 672                         sg_chain(rctx->dst, 2, sg);
 673         }
 674
 675         aead_request_set_tfm(subreq, child);
 676         aead_request_set_callback(subreq, req->base.flags, req->base.complete,
 677                                   req->base.data);
 678         aead_request_set_crypt(subreq, rctx->src,
 679                                req->src == req->dst ? rctx->src : rctx->dst,
 680                                req->cryptlen, iv);
 681         aead_request_set_ad(subreq, req->assoclen - 8);
 682
 683         return subreq;
 684 }
 685
 686 static int crypto_rfc4309_encrypt(struct aead_request *req)
 687 {
 688         if (req->assoclen != 16 && req->assoclen != 20)
 689                 return -EINVAL;
 690
 691         req = crypto_rfc4309_crypt(req);
 692
 693         return crypto_aead_encrypt(req);
 694 }
 695
 696 static int crypto_rfc4309_decrypt(struct aead_request *req)
 697 {
 698         if (req->assoclen != 16 && req->assoclen != 20)
 699                 return -EINVAL;
 700
 701         req = crypto_rfc4309_crypt(req);
 702
 703         return crypto_aead_decrypt(req);
 704 }
 705
 706 static int crypto_rfc4309_init_tfm(struct crypto_aead *tfm)
 707 {
 708         struct aead_instance *inst = aead_alg_instance(tfm);
 709         struct crypto_aead_spawn *spawn = aead_instance_ctx(inst);
 710         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(tfm);
 711         struct crypto_aead *aead;
 712         unsigned long align;
 713
 714         aead = crypto_spawn_aead(spawn);
 715         if (IS_ERR(aead))
 716                 return PTR_ERR(aead);
 717
 718         ctx->child = aead;
 719
 720         align = crypto_aead_alignmask(aead);
 721         align &= ~(crypto_tfm_ctx_alignment() - 1);
 722         crypto_aead_set_reqsize(
 723                 tfm,
 724                 sizeof(struct crypto_rfc4309_req_ctx) +
 725                 ALIGN(crypto_aead_reqsize(aead), crypto_tfm_ctx_alignment()) +
 726                 align + 32);
 727
 728         return 0;
 729 }
 730
 731 static void crypto_rfc4309_exit_tfm(struct crypto_aead *tfm)
 732 {
 733         struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(tfm);
 734
 735         crypto_free_aead(ctx->child);
 736 }
 737
 738 static void crypto_rfc4309_free(struct aead_instance *inst)
 739 {
 740         crypto_drop_aead(aead_instance_ctx(inst));
 741         kfree(inst);
 742 }
 743
 744 static int crypto_rfc4309_create(struct crypto_template *tmpl,
 745                                  struct rtattr **tb)
 746 {
 747         struct crypto_attr_type *algt;
 748         struct aead_instance *inst;
 749         struct crypto_aead_spawn *spawn;
 750         struct aead_alg *alg;
 751         const char *ccm_name;
 752         int err;
 753
 754         algt = crypto_get_attr_type(tb);
 755         if (IS_ERR(algt))
 756                 return PTR_ERR(algt);
 757
 758         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 759                 return -EINVAL;
 760
 761         ccm_name = crypto_attr_alg_name(tb[1]);
 762         if (IS_ERR(ccm_name))
 763                 return PTR_ERR(ccm_name);
 764
 765         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 766         if (!inst)
 767                 return -ENOMEM;
 768
 769         spawn = aead_instance_ctx(inst);
 770         crypto_set_aead_spawn(spawn, aead_crypto_instance(inst));
 771         err = crypto_grab_aead(spawn, ccm_name, 0,
 772                                crypto_requires_sync(algt->type, algt->mask));
 773         if (err)
 774                 goto out_free_inst;
 775
 776         alg = crypto_spawn_aead_alg(spawn);
 777
 778         err = -EINVAL;
 779
 780         /* We only support 16-byte blocks. */
 781         if (crypto_aead_alg_ivsize(alg) != 16)
 782                 goto out_drop_alg;
 783
 784         /* Not a stream cipher? */
 785         if (alg->base.cra_blocksize != 1)
 786                 goto out_drop_alg;
 787
 788         err = -ENAMETOOLONG;
 789         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 790                      "rfc4309(%s)", alg->base.cra_name) >=
 791             CRYPTO_MAX_ALG_NAME ||
 792             snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 793                      "rfc4309(%s)", alg->base.cra_driver_name) >=
 794             CRYPTO_MAX_ALG_NAME)
 795                 goto out_drop_alg;
 796
 797         inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
 798         inst->alg.base.cra_priority = alg->base.cra_priority;
 799         inst->alg.base.cra_blocksize = 1;
 800         inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
 801
 802         inst->alg.ivsize = 8;
 803         inst->alg.chunksize = crypto_aead_alg_chunksize(alg);
 804         inst->alg.maxauthsize = 16;
 805
 806         inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);
 807
 808         inst->alg.init = crypto_rfc4309_init_tfm;
 809         inst->alg.exit = crypto_rfc4309_exit_tfm;
 810
 811         inst->alg.setkey = crypto_rfc4309_setkey;
 812         inst->alg.setauthsize = crypto_rfc4309_setauthsize;
 813         inst->alg.encrypt = crypto_rfc4309_encrypt;
 814         inst->alg.decrypt = crypto_rfc4309_decrypt;
 815
 816         inst->free = crypto_rfc4309_free;
 817
 818         err = aead_register_instance(tmpl, inst);
 819         if (err)
 820                 goto out_drop_alg;
 821
 822 out:
 823         return err;
 824
 825 out_drop_alg:
 826         crypto_drop_aead(spawn);
 827 out_free_inst:
 828         kfree(inst);
 829         goto out;
 830 }
 831
 832 static int crypto_cbcmac_digest_setkey(struct crypto_shash *parent,
 833                                      const u8 *inkey, unsigned int keylen)
 834 {
 835         struct cbcmac_tfm_ctx *ctx = crypto_shash_ctx(parent);
 836
 837         return crypto_cipher_setkey(ctx->child, inkey, keylen);
 838 }
 839
 840 static int crypto_cbcmac_digest_init(struct shash_desc *pdesc)
 841 {
 842         struct cbcmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
 843         int bs = crypto_shash_digestsize(pdesc->tfm);
 844         u8 *dg = (u8 *)ctx + crypto_shash_descsize(pdesc->tfm) - bs;
 845
 846         ctx->len = 0;
 847         memset(dg, 0, bs);
 848
 849         return 0;
 850 }
 851
 852 static int crypto_cbcmac_digest_update(struct shash_desc *pdesc, const u8 *p,
 853                                        unsigned int len)
 854 {
 855         struct crypto_shash *parent = pdesc->tfm;
 856         struct cbcmac_tfm_ctx *tctx = crypto_shash_ctx(parent);
 857         struct cbcmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
 858         struct crypto_cipher *tfm = tctx->child;
 859         int bs = crypto_shash_digestsize(parent);
 860         u8 *dg = (u8 *)ctx + crypto_shash_descsize(parent) - bs;
 861
 862         while (len > 0) {
 863                 unsigned int l = min(len, bs - ctx->len);
 864
 865                 crypto_xor(dg + ctx->len, p, l);
 866                 ctx->len +=l;
 867                 len -= l;
 868                 p += l;
 869
 870                 if (ctx->len == bs) {
 871                         crypto_cipher_encrypt_one(tfm, dg, dg);
 872                         ctx->len = 0;
 873                 }
 874         }
 875
 876         return 0;
 877 }
 878
 879 static int crypto_cbcmac_digest_final(struct shash_desc *pdesc, u8 *out)
 880 {
 881         struct crypto_shash *parent = pdesc->tfm;
 882         struct cbcmac_tfm_ctx *tctx = crypto_shash_ctx(parent);
 883         struct cbcmac_desc_ctx *ctx = shash_desc_ctx(pdesc);
 884         struct crypto_cipher *tfm = tctx->child;
 885         int bs = crypto_shash_digestsize(parent);
 886         u8 *dg = (u8 *)ctx + crypto_shash_descsize(parent) - bs;
 887
 888         if (ctx->len)
 889                 crypto_cipher_encrypt_one(tfm, dg, dg);
 890
 891         memcpy(out, dg, bs);
 892         return 0;
 893 }
 894
 895 static int cbcmac_init_tfm(struct crypto_tfm *tfm)
 896 {
 897         struct crypto_cipher *cipher;
 898         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 899         struct crypto_spawn *spawn = crypto_instance_ctx(inst);
 900         struct cbcmac_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
 901
 902         cipher = crypto_spawn_cipher(spawn);
 903         if (IS_ERR(cipher))
 904                 return PTR_ERR(cipher);
 905
 906         ctx->child = cipher;
 907
 908         return 0;
 909 };
 910
 911 static void cbcmac_exit_tfm(struct crypto_tfm *tfm)
 912 {
 913         struct cbcmac_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
 914         crypto_free_cipher(ctx->child);
 915 }
 916
 917 static int cbcmac_create(struct crypto_template *tmpl, struct rtattr **tb)
 918 {
 919         struct shash_instance *inst;
 920         struct crypto_alg *alg;
 921         int err;
 922
 923         err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
 924         if (err)
 925                 return err;
 926
 927         alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
 928                                   CRYPTO_ALG_TYPE_MASK);
 929         if (IS_ERR(alg))
 930                 return PTR_ERR(alg);
 931
 932         inst = shash_alloc_instance("cbcmac", alg);
 933         err = PTR_ERR(inst);
 934         if (IS_ERR(inst))
 935                 goto out_put_alg;
 936
 937         err = crypto_init_spawn(shash_instance_ctx(inst), alg,
 938                                 shash_crypto_instance(inst),
 939                                 CRYPTO_ALG_TYPE_MASK);
 940         if (err)
 941                 goto out_free_inst;
 942
 943         inst->alg.base.cra_priority = alg->cra_priority;
 944         inst->alg.base.cra_blocksize = 1;
 945
 946         inst->alg.digestsize = alg->cra_blocksize;
 947         inst->alg.descsize = ALIGN(sizeof(struct cbcmac_desc_ctx),
 948                                    alg->cra_alignmask + 1) +
 949                              alg->cra_blocksize;
 950
 951         inst->alg.base.cra_ctxsize = sizeof(struct cbcmac_tfm_ctx);
 952         inst->alg.base.cra_init = cbcmac_init_tfm;
 953         inst->alg.base.cra_exit = cbcmac_exit_tfm;
 954
 955         inst->alg.init = crypto_cbcmac_digest_init;
 956         inst->alg.update = crypto_cbcmac_digest_update;
 957         inst->alg.final = crypto_cbcmac_digest_final;
 958         inst->alg.setkey = crypto_cbcmac_digest_setkey;
 959
 960         err = shash_register_instance(tmpl, inst);
 961
 962 out_free_inst:
 963         if (err)
 964                 shash_free_instance(shash_crypto_instance(inst));
 965
 966 out_put_alg:
 967         crypto_mod_put(alg);
 968         return err;
 969 }
 970
 971 static struct crypto_template crypto_ccm_tmpls[] = {
 972         {
 973                 .name = "cbcmac",
 974                 .create = cbcmac_create,
 975                 .free = shash_free_instance,
 976                 .module = THIS_MODULE,
 977         }, {
 978                 .name = "ccm_base",
 979                 .create = crypto_ccm_base_create,
 980                 .module = THIS_MODULE,
 981         }, {
 982                 .name = "ccm",
 983                 .create = crypto_ccm_create,
 984                 .module = THIS_MODULE,
 985         }, {
 986                 .name = "rfc4309",
 987                 .create = crypto_rfc4309_create,
 988                 .module = THIS_MODULE,
 989         },
 990 };
 991
 992 static int __init crypto_ccm_module_init(void)
 993 {
 994         return crypto_register_templates(crypto_ccm_tmpls,
 995                                          ARRAY_SIZE(crypto_ccm_tmpls));
 996 }
 997
 998 static void __exit crypto_ccm_module_exit(void)
 999 {
1000         crypto_unregister_templates(crypto_ccm_tmpls,
1001                                     ARRAY_SIZE(crypto_ccm_tmpls));
1002 }
1003
1004 subsys_initcall(crypto_ccm_module_init);
1005 module_exit(crypto_ccm_module_exit);
1006
1007 MODULE_LICENSE("GPL");
1008 MODULE_DESCRIPTION("Counter with CBC MAC");
1009 MODULE_ALIAS_CRYPTO("ccm_base");
1010 MODULE_ALIAS_CRYPTO("rfc4309");
1011 MODULE_ALIAS_CRYPTO("ccm");