crypto/gcm.c

   1 /*
   2  * GCM: Galois/Counter Mode.
   3  *
   4  * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
   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 version 2 as published
   8  * by the Free Software Foundation.
   9  */
  10
  11 #include <crypto/gf128mul.h>
  12 #include <crypto/internal/aead.h>
  13 #include <crypto/internal/skcipher.h>
  14 #include <crypto/scatterwalk.h>
  15 #include <linux/completion.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 struct gcm_instance_ctx {
  23         struct crypto_skcipher_spawn ctr;
  24 };
  25
  26 struct crypto_gcm_ctx {
  27         struct crypto_ablkcipher *ctr;
  28         struct gf128mul_4k *gf128;
  29 };
  30
  31 struct crypto_rfc4106_ctx {
  32         struct crypto_aead *child;
  33         u8 nonce[4];
  34 };
  35
  36 struct crypto_gcm_ghash_ctx {
  37         u32 bytes;
  38         u32 flags;
  39         struct gf128mul_4k *gf128;
  40         u8 buffer[16];
  41 };
  42
  43 struct crypto_gcm_req_priv_ctx {
  44         u8 auth_tag[16];
  45         u8 iauth_tag[16];
  46         struct scatterlist src[2];
  47         struct scatterlist dst[2];
  48         struct crypto_gcm_ghash_ctx ghash;
  49         struct ablkcipher_request abreq;
  50 };
  51
  52 struct crypto_gcm_setkey_result {
  53         int err;
  54         struct completion completion;
  55 };
  56
  57 static inline struct crypto_gcm_req_priv_ctx *crypto_gcm_reqctx(
  58         struct aead_request *req)
  59 {
  60         unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));
  61
  62         return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
  63 }
  64
  65 static void crypto_gcm_ghash_init(struct crypto_gcm_ghash_ctx *ctx, u32 flags,
  66                                   struct gf128mul_4k *gf128)
  67 {
  68         ctx->bytes = 0;
  69         ctx->flags = flags;
  70         ctx->gf128 = gf128;
  71         memset(ctx->buffer, 0, 16);
  72 }
  73
  74 static void crypto_gcm_ghash_update(struct crypto_gcm_ghash_ctx *ctx,
  75                                     const u8 *src, unsigned int srclen)
  76 {
  77         u8 *dst = ctx->buffer;
  78
  79         if (ctx->bytes) {
  80                 int n = min(srclen, ctx->bytes);
  81                 u8 *pos = dst + (16 - ctx->bytes);
  82
  83                 ctx->bytes -= n;
  84                 srclen -= n;
  85
  86                 while (n--)
  87                         *pos++ ^= *src++;
  88
  89                 if (!ctx->bytes)
  90                         gf128mul_4k_lle((be128 *)dst, ctx->gf128);
  91         }
  92
  93         while (srclen >= 16) {
  94                 crypto_xor(dst, src, 16);
  95                 gf128mul_4k_lle((be128 *)dst, ctx->gf128);
  96                 src += 16;
  97                 srclen -= 16;
  98         }
  99
 100         if (srclen) {
 101                 ctx->bytes = 16 - srclen;
 102                 while (srclen--)
 103                         *dst++ ^= *src++;
 104         }
 105 }
 106
 107 static void crypto_gcm_ghash_update_sg(struct crypto_gcm_ghash_ctx *ctx,
 108                                        struct scatterlist *sg, int len)
 109 {
 110         struct scatter_walk walk;
 111         u8 *src;
 112         int n;
 113
 114         if (!len)
 115                 return;
 116
 117         scatterwalk_start(&walk, sg);
 118
 119         while (len) {
 120                 n = scatterwalk_clamp(&walk, len);
 121
 122                 if (!n) {
 123                         scatterwalk_start(&walk, scatterwalk_sg_next(walk.sg));
 124                         n = scatterwalk_clamp(&walk, len);
 125                 }
 126
 127                 src = scatterwalk_map(&walk, 0);
 128
 129                 crypto_gcm_ghash_update(ctx, src, n);
 130                 len -= n;
 131
 132                 scatterwalk_unmap(src, 0);
 133                 scatterwalk_advance(&walk, n);
 134                 scatterwalk_done(&walk, 0, len);
 135                 if (len)
 136                         crypto_yield(ctx->flags);
 137         }
 138 }
 139
 140 static void crypto_gcm_ghash_flush(struct crypto_gcm_ghash_ctx *ctx)
 141 {
 142         u8 *dst = ctx->buffer;
 143
 144         if (ctx->bytes) {
 145                 u8 *tmp = dst + (16 - ctx->bytes);
 146
 147                 while (ctx->bytes--)
 148                         *tmp++ ^= 0;
 149
 150                 gf128mul_4k_lle((be128 *)dst, ctx->gf128);
 151         }
 152
 153         ctx->bytes = 0;
 154 }
 155
 156 static void crypto_gcm_ghash_final_xor(struct crypto_gcm_ghash_ctx *ctx,
 157                                        unsigned int authlen,
 158                                        unsigned int cryptlen, u8 *dst)
 159 {
 160         u8 *buf = ctx->buffer;
 161         u128 lengths;
 162
 163         lengths.a = cpu_to_be64(authlen * 8);
 164         lengths.b = cpu_to_be64(cryptlen * 8);
 165
 166         crypto_gcm_ghash_flush(ctx);
 167         crypto_xor(buf, (u8 *)&lengths, 16);
 168         gf128mul_4k_lle((be128 *)buf, ctx->gf128);
 169         crypto_xor(dst, buf, 16);
 170 }
 171
 172 static void crypto_gcm_setkey_done(struct crypto_async_request *req, int err)
 173 {
 174         struct crypto_gcm_setkey_result *result = req->data;
 175
 176         if (err == -EINPROGRESS)
 177                 return;
 178
 179         result->err = err;
 180         complete(&result->completion);
 181 }
 182
 183 static int crypto_gcm_setkey(struct crypto_aead *aead, const u8 *key,
 184                              unsigned int keylen)
 185 {
 186         struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
 187         struct crypto_ablkcipher *ctr = ctx->ctr;
 188         struct {
 189                 be128 hash;
 190                 u8 iv[8];
 191
 192                 struct crypto_gcm_setkey_result result;
 193
 194                 struct scatterlist sg[1];
 195                 struct ablkcipher_request req;
 196         } *data;
 197         int err;
 198
 199         crypto_ablkcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
 200         crypto_ablkcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
 201                                    CRYPTO_TFM_REQ_MASK);
 202
 203         err = crypto_ablkcipher_setkey(ctr, key, keylen);
 204         if (err)
 205                 return err;
 206
 207         crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctr) &
 208                                        CRYPTO_TFM_RES_MASK);
 209
 210         data = kzalloc(sizeof(*data) + crypto_ablkcipher_reqsize(ctr),
 211                        GFP_KERNEL);
 212         if (!data)
 213                 return -ENOMEM;
 214
 215         init_completion(&data->result.completion);
 216         sg_init_one(data->sg, &data->hash, sizeof(data->hash));
 217         ablkcipher_request_set_tfm(&data->req, ctr);
 218         ablkcipher_request_set_callback(&data->req, CRYPTO_TFM_REQ_MAY_SLEEP |
 219                                                     CRYPTO_TFM_REQ_MAY_BACKLOG,
 220                                         crypto_gcm_setkey_done,
 221                                         &data->result);
 222         ablkcipher_request_set_crypt(&data->req, data->sg, data->sg,
 223                                      sizeof(data->hash), data->iv);
 224
 225         err = crypto_ablkcipher_encrypt(&data->req);
 226         if (err == -EINPROGRESS || err == -EBUSY) {
 227                 err = wait_for_completion_interruptible(
 228                         &data->result.completion);
 229                 if (!err)
 230                         err = data->result.err;
 231         }
 232
 233         if (err)
 234                 goto out;
 235
 236         if (ctx->gf128 != NULL)
 237                 gf128mul_free_4k(ctx->gf128);
 238
 239         ctx->gf128 = gf128mul_init_4k_lle(&data->hash);
 240
 241         if (ctx->gf128 == NULL)
 242                 err = -ENOMEM;
 243
 244 out:
 245         kfree(data);
 246         return err;
 247 }
 248
 249 static int crypto_gcm_setauthsize(struct crypto_aead *tfm,
 250                                   unsigned int authsize)
 251 {
 252         switch (authsize) {
 253         case 4:
 254         case 8:
 255         case 12:
 256         case 13:
 257         case 14:
 258         case 15:
 259         case 16:
 260                 break;
 261         default:
 262                 return -EINVAL;
 263         }
 264
 265         return 0;
 266 }
 267
 268 static void crypto_gcm_init_crypt(struct ablkcipher_request *ablk_req,
 269                                   struct aead_request *req,
 270                                   unsigned int cryptlen)
 271 {
 272         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 273         struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead);
 274         struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
 275         u32 flags = req->base.tfm->crt_flags;
 276         struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;
 277         struct scatterlist *dst;
 278         __be32 counter = cpu_to_be32(1);
 279
 280         memset(pctx->auth_tag, 0, sizeof(pctx->auth_tag));
 281         memcpy(req->iv + 12, &counter, 4);
 282
 283         sg_init_table(pctx->src, 2);
 284         sg_set_buf(pctx->src, pctx->auth_tag, sizeof(pctx->auth_tag));
 285         scatterwalk_sg_chain(pctx->src, 2, req->src);
 286
 287         dst = pctx->src;
 288         if (req->src != req->dst) {
 289                 sg_init_table(pctx->dst, 2);
 290                 sg_set_buf(pctx->dst, pctx->auth_tag, sizeof(pctx->auth_tag));
 291                 scatterwalk_sg_chain(pctx->dst, 2, req->dst);
 292                 dst = pctx->dst;
 293         }
 294
 295         ablkcipher_request_set_tfm(ablk_req, ctx->ctr);
 296         ablkcipher_request_set_crypt(ablk_req, pctx->src, dst,
 297                                      cryptlen + sizeof(pctx->auth_tag),
 298                                      req->iv);
 299
 300         crypto_gcm_ghash_init(ghash, flags, ctx->gf128);
 301
 302         crypto_gcm_ghash_update_sg(ghash, req->assoc, req->assoclen);
 303         crypto_gcm_ghash_flush(ghash);
 304 }
 305
 306 static int crypto_gcm_hash(struct aead_request *req)
 307 {
 308         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 309         struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
 310         u8 *auth_tag = pctx->auth_tag;
 311         struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;
 312
 313         crypto_gcm_ghash_update_sg(ghash, req->dst, req->cryptlen);
 314         crypto_gcm_ghash_final_xor(ghash, req->assoclen, req->cryptlen,
 315                                    auth_tag);
 316
 317         scatterwalk_map_and_copy(auth_tag, req->dst, req->cryptlen,
 318                                  crypto_aead_authsize(aead), 1);
 319         return 0;
 320 }
 321
 322 static void crypto_gcm_encrypt_done(struct crypto_async_request *areq, int err)
 323 {
 324         struct aead_request *req = areq->data;
 325
 326         if (!err)
 327                 err = crypto_gcm_hash(req);
 328
 329         aead_request_complete(req, err);
 330 }
 331
 332 static int crypto_gcm_encrypt(struct aead_request *req)
 333 {
 334         struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
 335         struct ablkcipher_request *abreq = &pctx->abreq;
 336         int err;
 337
 338         crypto_gcm_init_crypt(abreq, req, req->cryptlen);
 339         ablkcipher_request_set_callback(abreq, aead_request_flags(req),
 340                                         crypto_gcm_encrypt_done, req);
 341
 342         err = crypto_ablkcipher_encrypt(abreq);
 343         if (err)
 344                 return err;
 345
 346         return crypto_gcm_hash(req);
 347 }
 348
 349 static int crypto_gcm_verify(struct aead_request *req)
 350 {
 351         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 352         struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
 353         struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;
 354         u8 *auth_tag = pctx->auth_tag;
 355         u8 *iauth_tag = pctx->iauth_tag;
 356         unsigned int authsize = crypto_aead_authsize(aead);
 357         unsigned int cryptlen = req->cryptlen - authsize;
 358
 359         crypto_gcm_ghash_final_xor(ghash, req->assoclen, cryptlen, auth_tag);
 360
 361         authsize = crypto_aead_authsize(aead);
 362         scatterwalk_map_and_copy(iauth_tag, req->src, cryptlen, authsize, 0);
 363         return memcmp(iauth_tag, auth_tag, authsize) ? -EBADMSG : 0;
 364 }
 365
 366 static void crypto_gcm_decrypt_done(struct crypto_async_request *areq, int err)
 367 {
 368         struct aead_request *req = areq->data;
 369
 370         if (!err)
 371                 err = crypto_gcm_verify(req);
 372
 373         aead_request_complete(req, err);
 374 }
 375
 376 static int crypto_gcm_decrypt(struct aead_request *req)
 377 {
 378         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 379         struct crypto_gcm_req_priv_ctx *pctx = crypto_gcm_reqctx(req);
 380         struct ablkcipher_request *abreq = &pctx->abreq;
 381         struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash;
 382         unsigned int cryptlen = req->cryptlen;
 383         unsigned int authsize = crypto_aead_authsize(aead);
 384         int err;
 385
 386         if (cryptlen < authsize)
 387                 return -EINVAL;
 388         cryptlen -= authsize;
 389
 390         crypto_gcm_init_crypt(abreq, req, cryptlen);
 391         ablkcipher_request_set_callback(abreq, aead_request_flags(req),
 392                                         crypto_gcm_decrypt_done, req);
 393
 394         crypto_gcm_ghash_update_sg(ghash, req->src, cryptlen);
 395
 396         err = crypto_ablkcipher_decrypt(abreq);
 397         if (err)
 398                 return err;
 399
 400         return crypto_gcm_verify(req);
 401 }
 402
 403 static int crypto_gcm_init_tfm(struct crypto_tfm *tfm)
 404 {
 405         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 406         struct gcm_instance_ctx *ictx = crypto_instance_ctx(inst);
 407         struct crypto_gcm_ctx *ctx = crypto_tfm_ctx(tfm);
 408         struct crypto_ablkcipher *ctr;
 409         unsigned long align;
 410         int err;
 411
 412         ctr = crypto_spawn_skcipher(&ictx->ctr);
 413         err = PTR_ERR(ctr);
 414         if (IS_ERR(ctr))
 415                 return err;
 416
 417         ctx->ctr = ctr;
 418         ctx->gf128 = NULL;
 419
 420         align = crypto_tfm_alg_alignmask(tfm);
 421         align &= ~(crypto_tfm_ctx_alignment() - 1);
 422         tfm->crt_aead.reqsize = align +
 423                                 sizeof(struct crypto_gcm_req_priv_ctx) +
 424                                 crypto_ablkcipher_reqsize(ctr);
 425
 426         return 0;
 427 }
 428
 429 static void crypto_gcm_exit_tfm(struct crypto_tfm *tfm)
 430 {
 431         struct crypto_gcm_ctx *ctx = crypto_tfm_ctx(tfm);
 432
 433         if (ctx->gf128 != NULL)
 434                 gf128mul_free_4k(ctx->gf128);
 435
 436         crypto_free_ablkcipher(ctx->ctr);
 437 }
 438
 439 static struct crypto_instance *crypto_gcm_alloc_common(struct rtattr **tb,
 440                                                        const char *full_name,
 441                                                        const char *ctr_name)
 442 {
 443         struct crypto_attr_type *algt;
 444         struct crypto_instance *inst;
 445         struct crypto_alg *ctr;
 446         struct gcm_instance_ctx *ctx;
 447         int err;
 448
 449         algt = crypto_get_attr_type(tb);
 450         err = PTR_ERR(algt);
 451         if (IS_ERR(algt))
 452                 return ERR_PTR(err);
 453
 454         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 455                 return ERR_PTR(-EINVAL);
 456
 457         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 458         if (!inst)
 459                 return ERR_PTR(-ENOMEM);
 460
 461         ctx = crypto_instance_ctx(inst);
 462         crypto_set_skcipher_spawn(&ctx->ctr, inst);
 463         err = crypto_grab_skcipher(&ctx->ctr, ctr_name, 0,
 464                                    crypto_requires_sync(algt->type,
 465                                                         algt->mask));
 466         if (err)
 467                 goto err_free_inst;
 468
 469         ctr = crypto_skcipher_spawn_alg(&ctx->ctr);
 470
 471         /* We only support 16-byte blocks. */
 472         if (ctr->cra_ablkcipher.ivsize != 16)
 473                 goto out_put_ctr;
 474
 475         /* Not a stream cipher? */
 476         err = -EINVAL;
 477         if (ctr->cra_blocksize != 1)
 478                 goto out_put_ctr;
 479
 480         err = -ENAMETOOLONG;
 481         if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 482                      "gcm_base(%s)", ctr->cra_driver_name) >=
 483             CRYPTO_MAX_ALG_NAME)
 484                 goto out_put_ctr;
 485
 486         memcpy(inst->alg.cra_name, full_name, CRYPTO_MAX_ALG_NAME);
 487
 488         inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
 489         inst->alg.cra_flags |= ctr->cra_flags & CRYPTO_ALG_ASYNC;
 490         inst->alg.cra_priority = ctr->cra_priority;
 491         inst->alg.cra_blocksize = 1;
 492         inst->alg.cra_alignmask = ctr->cra_alignmask | (__alignof__(u64) - 1);
 493         inst->alg.cra_type = &crypto_aead_type;
 494         inst->alg.cra_aead.ivsize = 16;
 495         inst->alg.cra_aead.maxauthsize = 16;
 496         inst->alg.cra_ctxsize = sizeof(struct crypto_gcm_ctx);
 497         inst->alg.cra_init = crypto_gcm_init_tfm;
 498         inst->alg.cra_exit = crypto_gcm_exit_tfm;
 499         inst->alg.cra_aead.setkey = crypto_gcm_setkey;
 500         inst->alg.cra_aead.setauthsize = crypto_gcm_setauthsize;
 501         inst->alg.cra_aead.encrypt = crypto_gcm_encrypt;
 502         inst->alg.cra_aead.decrypt = crypto_gcm_decrypt;
 503
 504 out:
 505         return inst;
 506
 507 out_put_ctr:
 508         crypto_drop_skcipher(&ctx->ctr);
 509 err_free_inst:
 510         kfree(inst);
 511         inst = ERR_PTR(err);
 512         goto out;
 513 }
 514
 515 static struct crypto_instance *crypto_gcm_alloc(struct rtattr **tb)
 516 {
 517         int err;
 518         const char *cipher_name;
 519         char ctr_name[CRYPTO_MAX_ALG_NAME];
 520         char full_name[CRYPTO_MAX_ALG_NAME];
 521
 522         cipher_name = crypto_attr_alg_name(tb[1]);
 523         err = PTR_ERR(cipher_name);
 524         if (IS_ERR(cipher_name))
 525                 return ERR_PTR(err);
 526
 527         if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)", cipher_name) >=
 528             CRYPTO_MAX_ALG_NAME)
 529                 return ERR_PTR(-ENAMETOOLONG);
 530
 531         if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "gcm(%s)", cipher_name) >=
 532             CRYPTO_MAX_ALG_NAME)
 533                 return ERR_PTR(-ENAMETOOLONG);
 534
 535         return crypto_gcm_alloc_common(tb, full_name, ctr_name);
 536 }
 537
 538 static void crypto_gcm_free(struct crypto_instance *inst)
 539 {
 540         struct gcm_instance_ctx *ctx = crypto_instance_ctx(inst);
 541
 542         crypto_drop_skcipher(&ctx->ctr);
 543         kfree(inst);
 544 }
 545
 546 static struct crypto_template crypto_gcm_tmpl = {
 547         .name = "gcm",
 548         .alloc = crypto_gcm_alloc,
 549         .free = crypto_gcm_free,
 550         .module = THIS_MODULE,
 551 };
 552
 553 static struct crypto_instance *crypto_gcm_base_alloc(struct rtattr **tb)
 554 {
 555         int err;
 556         const char *ctr_name;
 557         char full_name[CRYPTO_MAX_ALG_NAME];
 558
 559         ctr_name = crypto_attr_alg_name(tb[1]);
 560         err = PTR_ERR(ctr_name);
 561         if (IS_ERR(ctr_name))
 562                 return ERR_PTR(err);
 563
 564         if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "gcm_base(%s)",
 565                      ctr_name) >= CRYPTO_MAX_ALG_NAME)
 566                 return ERR_PTR(-ENAMETOOLONG);
 567
 568         return crypto_gcm_alloc_common(tb, full_name, ctr_name);
 569 }
 570
 571 static struct crypto_template crypto_gcm_base_tmpl = {
 572         .name = "gcm_base",
 573         .alloc = crypto_gcm_base_alloc,
 574         .free = crypto_gcm_free,
 575         .module = THIS_MODULE,
 576 };
 577
 578 static int crypto_rfc4106_setkey(struct crypto_aead *parent, const u8 *key,
 579                                  unsigned int keylen)
 580 {
 581         struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(parent);
 582         struct crypto_aead *child = ctx->child;
 583         int err;
 584
 585         if (keylen < 4)
 586                 return -EINVAL;
 587
 588         keylen -= 4;
 589         memcpy(ctx->nonce, key + keylen, 4);
 590
 591         crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 592         crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
 593                                      CRYPTO_TFM_REQ_MASK);
 594         err = crypto_aead_setkey(child, key, keylen);
 595         crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
 596                                       CRYPTO_TFM_RES_MASK);
 597
 598         return err;
 599 }
 600
 601 static int crypto_rfc4106_setauthsize(struct crypto_aead *parent,
 602                                       unsigned int authsize)
 603 {
 604         struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(parent);
 605
 606         switch (authsize) {
 607         case 8:
 608         case 12:
 609         case 16:
 610                 break;
 611         default:
 612                 return -EINVAL;
 613         }
 614
 615         return crypto_aead_setauthsize(ctx->child, authsize);
 616 }
 617
 618 static struct aead_request *crypto_rfc4106_crypt(struct aead_request *req)
 619 {
 620         struct aead_request *subreq = aead_request_ctx(req);
 621         struct crypto_aead *aead = crypto_aead_reqtfm(req);
 622         struct crypto_rfc4106_ctx *ctx = crypto_aead_ctx(aead);
 623         struct crypto_aead *child = ctx->child;
 624         u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
 625                            crypto_aead_alignmask(child) + 1);
 626
 627         memcpy(iv, ctx->nonce, 4);
 628         memcpy(iv + 4, req->iv, 8);
 629
 630         aead_request_set_tfm(subreq, child);
 631         aead_request_set_callback(subreq, req->base.flags, req->base.complete,
 632                                   req->base.data);
 633         aead_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, iv);
 634         aead_request_set_assoc(subreq, req->assoc, req->assoclen);
 635
 636         return subreq;
 637 }
 638
 639 static int crypto_rfc4106_encrypt(struct aead_request *req)
 640 {
 641         req = crypto_rfc4106_crypt(req);
 642
 643         return crypto_aead_encrypt(req);
 644 }
 645
 646 static int crypto_rfc4106_decrypt(struct aead_request *req)
 647 {
 648         req = crypto_rfc4106_crypt(req);
 649
 650         return crypto_aead_decrypt(req);
 651 }
 652
 653 static int crypto_rfc4106_init_tfm(struct crypto_tfm *tfm)
 654 {
 655         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 656         struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst);
 657         struct crypto_rfc4106_ctx *ctx = crypto_tfm_ctx(tfm);
 658         struct crypto_aead *aead;
 659         unsigned long align;
 660
 661         aead = crypto_spawn_aead(spawn);
 662         if (IS_ERR(aead))
 663                 return PTR_ERR(aead);
 664
 665         ctx->child = aead;
 666
 667         align = crypto_aead_alignmask(aead);
 668         align &= ~(crypto_tfm_ctx_alignment() - 1);
 669         tfm->crt_aead.reqsize = sizeof(struct aead_request) +
 670                                 ALIGN(crypto_aead_reqsize(aead),
 671                                       crypto_tfm_ctx_alignment()) +
 672                                 align + 16;
 673
 674         return 0;
 675 }
 676
 677 static void crypto_rfc4106_exit_tfm(struct crypto_tfm *tfm)
 678 {
 679         struct crypto_rfc4106_ctx *ctx = crypto_tfm_ctx(tfm);
 680
 681         crypto_free_aead(ctx->child);
 682 }
 683
 684 static struct crypto_instance *crypto_rfc4106_alloc(struct rtattr **tb)
 685 {
 686         struct crypto_attr_type *algt;
 687         struct crypto_instance *inst;
 688         struct crypto_aead_spawn *spawn;
 689         struct crypto_alg *alg;
 690         const char *ccm_name;
 691         int err;
 692
 693         algt = crypto_get_attr_type(tb);
 694         err = PTR_ERR(algt);
 695         if (IS_ERR(algt))
 696                 return ERR_PTR(err);
 697
 698         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 699                 return ERR_PTR(-EINVAL);
 700
 701         ccm_name = crypto_attr_alg_name(tb[1]);
 702         err = PTR_ERR(ccm_name);
 703         if (IS_ERR(ccm_name))
 704                 return ERR_PTR(err);
 705
 706         inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 707         if (!inst)
 708                 return ERR_PTR(-ENOMEM);
 709
 710         spawn = crypto_instance_ctx(inst);
 711         crypto_set_aead_spawn(spawn, inst);
 712         err = crypto_grab_aead(spawn, ccm_name, 0,
 713                                crypto_requires_sync(algt->type, algt->mask));
 714         if (err)
 715                 goto out_free_inst;
 716
 717         alg = crypto_aead_spawn_alg(spawn);
 718
 719         err = -EINVAL;
 720
 721         /* We only support 16-byte blocks. */
 722         if (alg->cra_aead.ivsize != 16)
 723                 goto out_drop_alg;
 724
 725         /* Not a stream cipher? */
 726         if (alg->cra_blocksize != 1)
 727                 goto out_drop_alg;
 728
 729         err = -ENAMETOOLONG;
 730         if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
 731                      "rfc4106(%s)", alg->cra_name) >= CRYPTO_MAX_ALG_NAME ||
 732             snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 733                      "rfc4106(%s)", alg->cra_driver_name) >=
 734             CRYPTO_MAX_ALG_NAME)
 735                 goto out_drop_alg;
 736
 737         inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
 738         inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
 739         inst->alg.cra_priority = alg->cra_priority;
 740         inst->alg.cra_blocksize = 1;
 741         inst->alg.cra_alignmask = alg->cra_alignmask;
 742         inst->alg.cra_type = &crypto_nivaead_type;
 743
 744         inst->alg.cra_aead.ivsize = 8;
 745         inst->alg.cra_aead.maxauthsize = 16;
 746
 747         inst->alg.cra_ctxsize = sizeof(struct crypto_rfc4106_ctx);
 748
 749         inst->alg.cra_init = crypto_rfc4106_init_tfm;
 750         inst->alg.cra_exit = crypto_rfc4106_exit_tfm;
 751
 752         inst->alg.cra_aead.setkey = crypto_rfc4106_setkey;
 753         inst->alg.cra_aead.setauthsize = crypto_rfc4106_setauthsize;
 754         inst->alg.cra_aead.encrypt = crypto_rfc4106_encrypt;
 755         inst->alg.cra_aead.decrypt = crypto_rfc4106_decrypt;
 756
 757         inst->alg.cra_aead.geniv = "seqiv";
 758
 759 out:
 760         return inst;
 761
 762 out_drop_alg:
 763         crypto_drop_aead(spawn);
 764 out_free_inst:
 765         kfree(inst);
 766         inst = ERR_PTR(err);
 767         goto out;
 768 }
 769
 770 static void crypto_rfc4106_free(struct crypto_instance *inst)
 771 {
 772         crypto_drop_spawn(crypto_instance_ctx(inst));
 773         kfree(inst);
 774 }
 775
 776 static struct crypto_template crypto_rfc4106_tmpl = {
 777         .name = "rfc4106",
 778         .alloc = crypto_rfc4106_alloc,
 779         .free = crypto_rfc4106_free,
 780         .module = THIS_MODULE,
 781 };
 782
 783 static int __init crypto_gcm_module_init(void)
 784 {
 785         int err;
 786
 787         err = crypto_register_template(&crypto_gcm_base_tmpl);
 788         if (err)
 789                 goto out;
 790
 791         err = crypto_register_template(&crypto_gcm_tmpl);
 792         if (err)
 793                 goto out_undo_base;
 794
 795         err = crypto_register_template(&crypto_rfc4106_tmpl);
 796         if (err)
 797                 goto out_undo_gcm;
 798
 799 out:
 800         return err;
 801
 802 out_undo_gcm:
 803         crypto_unregister_template(&crypto_gcm_tmpl);
 804 out_undo_base:
 805         crypto_unregister_template(&crypto_gcm_base_tmpl);
 806         goto out;
 807 }
 808
 809 static void __exit crypto_gcm_module_exit(void)
 810 {
 811         crypto_unregister_template(&crypto_rfc4106_tmpl);
 812         crypto_unregister_template(&crypto_gcm_tmpl);
 813         crypto_unregister_template(&crypto_gcm_base_tmpl);
 814 }
 815
 816 module_init(crypto_gcm_module_init);
 817 module_exit(crypto_gcm_module_exit);
 818
 819 MODULE_LICENSE("GPL");
 820 MODULE_DESCRIPTION("Galois/Counter Mode");
 821 MODULE_AUTHOR("Mikko Herranen <mh1@iki.fi>");
 822 MODULE_ALIAS("gcm_base");
 823 MODULE_ALIAS("rfc4106");