crypto/chacha20poly1305.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * ChaCha20-Poly1305 AEAD, RFC7539
   4  *
   5  * Copyright (C) 2015 Martin Willi
   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 <crypto/chacha.h>
  13 #include <crypto/poly1305.h>
  14 #include <linux/err.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18
  19 #include "internal.h"
  20
  21 struct chachapoly_instance_ctx {
  22         struct crypto_skcipher_spawn chacha;
  23         struct crypto_ahash_spawn poly;
  24         unsigned int saltlen;
  25 };
  26
  27 struct chachapoly_ctx {
  28         struct crypto_skcipher *chacha;
  29         struct crypto_ahash *poly;
  30         /* key bytes we use for the ChaCha20 IV */
  31         unsigned int saltlen;
  32         u8 salt[];
  33 };
  34
  35 struct poly_req {
  36         /* zero byte padding for AD/ciphertext, as needed */
  37         u8 pad[POLY1305_BLOCK_SIZE];
  38         /* tail data with AD/ciphertext lengths */
  39         struct {
  40                 __le64 assoclen;
  41                 __le64 cryptlen;
  42         } tail;
  43         struct scatterlist src[1];
  44         struct ahash_request req; /* must be last member */
  45 };
  46
  47 struct chacha_req {
  48         u8 iv[CHACHA_IV_SIZE];
  49         struct scatterlist src[1];
  50         struct skcipher_request req; /* must be last member */
  51 };
  52
  53 struct chachapoly_req_ctx {
  54         struct scatterlist src[2];
  55         struct scatterlist dst[2];
  56         /* the key we generate for Poly1305 using Chacha20 */
  57         u8 key[POLY1305_KEY_SIZE];
  58         /* calculated Poly1305 tag */
  59         u8 tag[POLY1305_DIGEST_SIZE];
  60         /* length of data to en/decrypt, without ICV */
  61         unsigned int cryptlen;
  62         /* Actual AD, excluding IV */
  63         unsigned int assoclen;
  64         /* request flags, with MAY_SLEEP cleared if needed */
  65         u32 flags;
  66         union {
  67                 struct poly_req poly;
  68                 struct chacha_req chacha;
  69         } u;
  70 };
  71
  72 static inline void async_done_continue(struct aead_request *req, int err,
  73                                        int (*cont)(struct aead_request *))
  74 {
  75         if (!err) {
  76                 struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
  77
  78                 rctx->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
  79                 err = cont(req);
  80         }
  81
  82         if (err != -EINPROGRESS && err != -EBUSY)
  83                 aead_request_complete(req, err);
  84 }
  85
  86 static void chacha_iv(u8 *iv, struct aead_request *req, u32 icb)
  87 {
  88         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
  89         __le32 leicb = cpu_to_le32(icb);
  90
  91         memcpy(iv, &leicb, sizeof(leicb));
  92         memcpy(iv + sizeof(leicb), ctx->salt, ctx->saltlen);
  93         memcpy(iv + sizeof(leicb) + ctx->saltlen, req->iv,
  94                CHACHA_IV_SIZE - sizeof(leicb) - ctx->saltlen);
  95 }
  96
  97 static int poly_verify_tag(struct aead_request *req)
  98 {
  99         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 100         u8 tag[sizeof(rctx->tag)];
 101
 102         scatterwalk_map_and_copy(tag, req->src,
 103                                  req->assoclen + rctx->cryptlen,
 104                                  sizeof(tag), 0);
 105         if (crypto_memneq(tag, rctx->tag, sizeof(tag)))
 106                 return -EBADMSG;
 107         return 0;
 108 }
 109
 110 static int poly_copy_tag(struct aead_request *req)
 111 {
 112         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 113
 114         scatterwalk_map_and_copy(rctx->tag, req->dst,
 115                                  req->assoclen + rctx->cryptlen,
 116                                  sizeof(rctx->tag), 1);
 117         return 0;
 118 }
 119
 120 static void chacha_decrypt_done(struct crypto_async_request *areq, int err)
 121 {
 122         async_done_continue(areq->data, err, poly_verify_tag);
 123 }
 124
 125 static int chacha_decrypt(struct aead_request *req)
 126 {
 127         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 128         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 129         struct chacha_req *creq = &rctx->u.chacha;
 130         struct scatterlist *src, *dst;
 131         int err;
 132
 133         if (rctx->cryptlen == 0)
 134                 goto skip;
 135
 136         chacha_iv(creq->iv, req, 1);
 137
 138         src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
 139         dst = src;
 140         if (req->src != req->dst)
 141                 dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
 142
 143         skcipher_request_set_callback(&creq->req, rctx->flags,
 144                                       chacha_decrypt_done, req);
 145         skcipher_request_set_tfm(&creq->req, ctx->chacha);
 146         skcipher_request_set_crypt(&creq->req, src, dst,
 147                                    rctx->cryptlen, creq->iv);
 148         err = crypto_skcipher_decrypt(&creq->req);
 149         if (err)
 150                 return err;
 151
 152 skip:
 153         return poly_verify_tag(req);
 154 }
 155
 156 static int poly_tail_continue(struct aead_request *req)
 157 {
 158         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 159
 160         if (rctx->cryptlen == req->cryptlen) /* encrypting */
 161                 return poly_copy_tag(req);
 162
 163         return chacha_decrypt(req);
 164 }
 165
 166 static void poly_tail_done(struct crypto_async_request *areq, int err)
 167 {
 168         async_done_continue(areq->data, err, poly_tail_continue);
 169 }
 170
 171 static int poly_tail(struct aead_request *req)
 172 {
 173         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 174         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 175         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 176         struct poly_req *preq = &rctx->u.poly;
 177         int err;
 178
 179         preq->tail.assoclen = cpu_to_le64(rctx->assoclen);
 180         preq->tail.cryptlen = cpu_to_le64(rctx->cryptlen);
 181         sg_init_one(preq->src, &preq->tail, sizeof(preq->tail));
 182
 183         ahash_request_set_callback(&preq->req, rctx->flags,
 184                                    poly_tail_done, req);
 185         ahash_request_set_tfm(&preq->req, ctx->poly);
 186         ahash_request_set_crypt(&preq->req, preq->src,
 187                                 rctx->tag, sizeof(preq->tail));
 188
 189         err = crypto_ahash_finup(&preq->req);
 190         if (err)
 191                 return err;
 192
 193         return poly_tail_continue(req);
 194 }
 195
 196 static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
 197 {
 198         async_done_continue(areq->data, err, poly_tail);
 199 }
 200
 201 static int poly_cipherpad(struct aead_request *req)
 202 {
 203         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 204         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 205         struct poly_req *preq = &rctx->u.poly;
 206         unsigned int padlen;
 207         int err;
 208
 209         padlen = -rctx->cryptlen % POLY1305_BLOCK_SIZE;
 210         memset(preq->pad, 0, sizeof(preq->pad));
 211         sg_init_one(preq->src, preq->pad, padlen);
 212
 213         ahash_request_set_callback(&preq->req, rctx->flags,
 214                                    poly_cipherpad_done, req);
 215         ahash_request_set_tfm(&preq->req, ctx->poly);
 216         ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
 217
 218         err = crypto_ahash_update(&preq->req);
 219         if (err)
 220                 return err;
 221
 222         return poly_tail(req);
 223 }
 224
 225 static void poly_cipher_done(struct crypto_async_request *areq, int err)
 226 {
 227         async_done_continue(areq->data, err, poly_cipherpad);
 228 }
 229
 230 static int poly_cipher(struct aead_request *req)
 231 {
 232         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 233         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 234         struct poly_req *preq = &rctx->u.poly;
 235         struct scatterlist *crypt = req->src;
 236         int err;
 237
 238         if (rctx->cryptlen == req->cryptlen) /* encrypting */
 239                 crypt = req->dst;
 240
 241         crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);
 242
 243         ahash_request_set_callback(&preq->req, rctx->flags,
 244                                    poly_cipher_done, req);
 245         ahash_request_set_tfm(&preq->req, ctx->poly);
 246         ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);
 247
 248         err = crypto_ahash_update(&preq->req);
 249         if (err)
 250                 return err;
 251
 252         return poly_cipherpad(req);
 253 }
 254
 255 static void poly_adpad_done(struct crypto_async_request *areq, int err)
 256 {
 257         async_done_continue(areq->data, err, poly_cipher);
 258 }
 259
 260 static int poly_adpad(struct aead_request *req)
 261 {
 262         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 263         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 264         struct poly_req *preq = &rctx->u.poly;
 265         unsigned int padlen;
 266         int err;
 267
 268         padlen = -rctx->assoclen % POLY1305_BLOCK_SIZE;
 269         memset(preq->pad, 0, sizeof(preq->pad));
 270         sg_init_one(preq->src, preq->pad, padlen);
 271
 272         ahash_request_set_callback(&preq->req, rctx->flags,
 273                                    poly_adpad_done, req);
 274         ahash_request_set_tfm(&preq->req, ctx->poly);
 275         ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
 276
 277         err = crypto_ahash_update(&preq->req);
 278         if (err)
 279                 return err;
 280
 281         return poly_cipher(req);
 282 }
 283
 284 static void poly_ad_done(struct crypto_async_request *areq, int err)
 285 {
 286         async_done_continue(areq->data, err, poly_adpad);
 287 }
 288
 289 static int poly_ad(struct aead_request *req)
 290 {
 291         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 292         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 293         struct poly_req *preq = &rctx->u.poly;
 294         int err;
 295
 296         ahash_request_set_callback(&preq->req, rctx->flags,
 297                                    poly_ad_done, req);
 298         ahash_request_set_tfm(&preq->req, ctx->poly);
 299         ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);
 300
 301         err = crypto_ahash_update(&preq->req);
 302         if (err)
 303                 return err;
 304
 305         return poly_adpad(req);
 306 }
 307
 308 static void poly_setkey_done(struct crypto_async_request *areq, int err)
 309 {
 310         async_done_continue(areq->data, err, poly_ad);
 311 }
 312
 313 static int poly_setkey(struct aead_request *req)
 314 {
 315         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 316         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 317         struct poly_req *preq = &rctx->u.poly;
 318         int err;
 319
 320         sg_init_one(preq->src, rctx->key, sizeof(rctx->key));
 321
 322         ahash_request_set_callback(&preq->req, rctx->flags,
 323                                    poly_setkey_done, req);
 324         ahash_request_set_tfm(&preq->req, ctx->poly);
 325         ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key));
 326
 327         err = crypto_ahash_update(&preq->req);
 328         if (err)
 329                 return err;
 330
 331         return poly_ad(req);
 332 }
 333
 334 static void poly_init_done(struct crypto_async_request *areq, int err)
 335 {
 336         async_done_continue(areq->data, err, poly_setkey);
 337 }
 338
 339 static int poly_init(struct aead_request *req)
 340 {
 341         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 342         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 343         struct poly_req *preq = &rctx->u.poly;
 344         int err;
 345
 346         ahash_request_set_callback(&preq->req, rctx->flags,
 347                                    poly_init_done, req);
 348         ahash_request_set_tfm(&preq->req, ctx->poly);
 349
 350         err = crypto_ahash_init(&preq->req);
 351         if (err)
 352                 return err;
 353
 354         return poly_setkey(req);
 355 }
 356
 357 static void poly_genkey_done(struct crypto_async_request *areq, int err)
 358 {
 359         async_done_continue(areq->data, err, poly_init);
 360 }
 361
 362 static int poly_genkey(struct aead_request *req)
 363 {
 364         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 365         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 366         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 367         struct chacha_req *creq = &rctx->u.chacha;
 368         int err;
 369
 370         rctx->assoclen = req->assoclen;
 371
 372         if (crypto_aead_ivsize(tfm) == 8) {
 373                 if (rctx->assoclen < 8)
 374                         return -EINVAL;
 375                 rctx->assoclen -= 8;
 376         }
 377
 378         memset(rctx->key, 0, sizeof(rctx->key));
 379         sg_init_one(creq->src, rctx->key, sizeof(rctx->key));
 380
 381         chacha_iv(creq->iv, req, 0);
 382
 383         skcipher_request_set_callback(&creq->req, rctx->flags,
 384                                       poly_genkey_done, req);
 385         skcipher_request_set_tfm(&creq->req, ctx->chacha);
 386         skcipher_request_set_crypt(&creq->req, creq->src, creq->src,
 387                                    POLY1305_KEY_SIZE, creq->iv);
 388
 389         err = crypto_skcipher_decrypt(&creq->req);
 390         if (err)
 391                 return err;
 392
 393         return poly_init(req);
 394 }
 395
 396 static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
 397 {
 398         async_done_continue(areq->data, err, poly_genkey);
 399 }
 400
 401 static int chacha_encrypt(struct aead_request *req)
 402 {
 403         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 404         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 405         struct chacha_req *creq = &rctx->u.chacha;
 406         struct scatterlist *src, *dst;
 407         int err;
 408
 409         if (req->cryptlen == 0)
 410                 goto skip;
 411
 412         chacha_iv(creq->iv, req, 1);
 413
 414         src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
 415         dst = src;
 416         if (req->src != req->dst)
 417                 dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
 418
 419         skcipher_request_set_callback(&creq->req, rctx->flags,
 420                                       chacha_encrypt_done, req);
 421         skcipher_request_set_tfm(&creq->req, ctx->chacha);
 422         skcipher_request_set_crypt(&creq->req, src, dst,
 423                                    req->cryptlen, creq->iv);
 424         err = crypto_skcipher_encrypt(&creq->req);
 425         if (err)
 426                 return err;
 427
 428 skip:
 429         return poly_genkey(req);
 430 }
 431
 432 static int chachapoly_encrypt(struct aead_request *req)
 433 {
 434         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 435
 436         rctx->cryptlen = req->cryptlen;
 437         rctx->flags = aead_request_flags(req);
 438
 439         /* encrypt call chain:
 440          * - chacha_encrypt/done()
 441          * - poly_genkey/done()
 442          * - poly_init/done()
 443          * - poly_setkey/done()
 444          * - poly_ad/done()
 445          * - poly_adpad/done()
 446          * - poly_cipher/done()
 447          * - poly_cipherpad/done()
 448          * - poly_tail/done/continue()
 449          * - poly_copy_tag()
 450          */
 451         return chacha_encrypt(req);
 452 }
 453
 454 static int chachapoly_decrypt(struct aead_request *req)
 455 {
 456         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 457
 458         rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
 459         rctx->flags = aead_request_flags(req);
 460
 461         /* decrypt call chain:
 462          * - poly_genkey/done()
 463          * - poly_init/done()
 464          * - poly_setkey/done()
 465          * - poly_ad/done()
 466          * - poly_adpad/done()
 467          * - poly_cipher/done()
 468          * - poly_cipherpad/done()
 469          * - poly_tail/done/continue()
 470          * - chacha_decrypt/done()
 471          * - poly_verify_tag()
 472          */
 473         return poly_genkey(req);
 474 }
 475
 476 static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
 477                              unsigned int keylen)
 478 {
 479         struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
 480         int err;
 481
 482         if (keylen != ctx->saltlen + CHACHA_KEY_SIZE)
 483                 return -EINVAL;
 484
 485         keylen -= ctx->saltlen;
 486         memcpy(ctx->salt, key + keylen, ctx->saltlen);
 487
 488         crypto_skcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
 489         crypto_skcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
 490                                                CRYPTO_TFM_REQ_MASK);
 491
 492         err = crypto_skcipher_setkey(ctx->chacha, key, keylen);
 493         crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctx->chacha) &
 494                                     CRYPTO_TFM_RES_MASK);
 495         return err;
 496 }
 497
 498 static int chachapoly_setauthsize(struct crypto_aead *tfm,
 499                                   unsigned int authsize)
 500 {
 501         if (authsize != POLY1305_DIGEST_SIZE)
 502                 return -EINVAL;
 503
 504         return 0;
 505 }
 506
 507 static int chachapoly_init(struct crypto_aead *tfm)
 508 {
 509         struct aead_instance *inst = aead_alg_instance(tfm);
 510         struct chachapoly_instance_ctx *ictx = aead_instance_ctx(inst);
 511         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 512         struct crypto_skcipher *chacha;
 513         struct crypto_ahash *poly;
 514         unsigned long align;
 515
 516         poly = crypto_spawn_ahash(&ictx->poly);
 517         if (IS_ERR(poly))
 518                 return PTR_ERR(poly);
 519
 520         chacha = crypto_spawn_skcipher(&ictx->chacha);
 521         if (IS_ERR(chacha)) {
 522                 crypto_free_ahash(poly);
 523                 return PTR_ERR(chacha);
 524         }
 525
 526         ctx->chacha = chacha;
 527         ctx->poly = poly;
 528         ctx->saltlen = ictx->saltlen;
 529
 530         align = crypto_aead_alignmask(tfm);
 531         align &= ~(crypto_tfm_ctx_alignment() - 1);
 532         crypto_aead_set_reqsize(
 533                 tfm,
 534                 align + offsetof(struct chachapoly_req_ctx, u) +
 535                 max(offsetof(struct chacha_req, req) +
 536                     sizeof(struct skcipher_request) +
 537                     crypto_skcipher_reqsize(chacha),
 538                     offsetof(struct poly_req, req) +
 539                     sizeof(struct ahash_request) +
 540                     crypto_ahash_reqsize(poly)));
 541
 542         return 0;
 543 }
 544
 545 static void chachapoly_exit(struct crypto_aead *tfm)
 546 {
 547         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 548
 549         crypto_free_ahash(ctx->poly);
 550         crypto_free_skcipher(ctx->chacha);
 551 }
 552
 553 static void chachapoly_free(struct aead_instance *inst)
 554 {
 555         struct chachapoly_instance_ctx *ctx = aead_instance_ctx(inst);
 556
 557         crypto_drop_skcipher(&ctx->chacha);
 558         crypto_drop_ahash(&ctx->poly);
 559         kfree(inst);
 560 }
 561
 562 static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
 563                              const char *name, unsigned int ivsize)
 564 {
 565         struct crypto_attr_type *algt;
 566         struct aead_instance *inst;
 567         struct skcipher_alg *chacha;
 568         struct crypto_alg *poly;
 569         struct hash_alg_common *poly_hash;
 570         struct chachapoly_instance_ctx *ctx;
 571         const char *chacha_name, *poly_name;
 572         int err;
 573
 574         if (ivsize > CHACHAPOLY_IV_SIZE)
 575                 return -EINVAL;
 576
 577         algt = crypto_get_attr_type(tb);
 578         if (IS_ERR(algt))
 579                 return PTR_ERR(algt);
 580
 581         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 582                 return -EINVAL;
 583
 584         chacha_name = crypto_attr_alg_name(tb[1]);
 585         if (IS_ERR(chacha_name))
 586                 return PTR_ERR(chacha_name);
 587         poly_name = crypto_attr_alg_name(tb[2]);
 588         if (IS_ERR(poly_name))
 589                 return PTR_ERR(poly_name);
 590
 591         poly = crypto_find_alg(poly_name, &crypto_ahash_type,
 592                                CRYPTO_ALG_TYPE_HASH,
 593                                CRYPTO_ALG_TYPE_AHASH_MASK |
 594                                crypto_requires_sync(algt->type,
 595                                                     algt->mask));
 596         if (IS_ERR(poly))
 597                 return PTR_ERR(poly);
 598         poly_hash = __crypto_hash_alg_common(poly);
 599
 600         err = -EINVAL;
 601         if (poly_hash->digestsize != POLY1305_DIGEST_SIZE)
 602                 goto out_put_poly;
 603
 604         err = -ENOMEM;
 605         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 606         if (!inst)
 607                 goto out_put_poly;
 608
 609         ctx = aead_instance_ctx(inst);
 610         ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
 611         err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
 612                                       aead_crypto_instance(inst));
 613         if (err)
 614                 goto err_free_inst;
 615
 616         crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
 617         err = crypto_grab_skcipher(&ctx->chacha, chacha_name, 0,
 618                                    crypto_requires_sync(algt->type,
 619                                                         algt->mask));
 620         if (err)
 621                 goto err_drop_poly;
 622
 623         chacha = crypto_spawn_skcipher_alg(&ctx->chacha);
 624
 625         err = -EINVAL;
 626         /* Need 16-byte IV size, including Initial Block Counter value */
 627         if (crypto_skcipher_alg_ivsize(chacha) != CHACHA_IV_SIZE)
 628                 goto out_drop_chacha;
 629         /* Not a stream cipher? */
 630         if (chacha->base.cra_blocksize != 1)
 631                 goto out_drop_chacha;
 632
 633         err = -ENAMETOOLONG;
 634         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 635                      "%s(%s,%s)", name, chacha->base.cra_name,
 636                      poly->cra_name) >= CRYPTO_MAX_ALG_NAME)
 637                 goto out_drop_chacha;
 638         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 639                      "%s(%s,%s)", name, chacha->base.cra_driver_name,
 640                      poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 641                 goto out_drop_chacha;
 642
 643         inst->alg.base.cra_flags = (chacha->base.cra_flags | poly->cra_flags) &
 644                                    CRYPTO_ALG_ASYNC;
 645         inst->alg.base.cra_priority = (chacha->base.cra_priority +
 646                                        poly->cra_priority) / 2;
 647         inst->alg.base.cra_blocksize = 1;
 648         inst->alg.base.cra_alignmask = chacha->base.cra_alignmask |
 649                                        poly->cra_alignmask;
 650         inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
 651                                      ctx->saltlen;
 652         inst->alg.ivsize = ivsize;
 653         inst->alg.chunksize = crypto_skcipher_alg_chunksize(chacha);
 654         inst->alg.maxauthsize = POLY1305_DIGEST_SIZE;
 655         inst->alg.init = chachapoly_init;
 656         inst->alg.exit = chachapoly_exit;
 657         inst->alg.encrypt = chachapoly_encrypt;
 658         inst->alg.decrypt = chachapoly_decrypt;
 659         inst->alg.setkey = chachapoly_setkey;
 660         inst->alg.setauthsize = chachapoly_setauthsize;
 661
 662         inst->free = chachapoly_free;
 663
 664         err = aead_register_instance(tmpl, inst);
 665         if (err)
 666                 goto out_drop_chacha;
 667
 668 out_put_poly:
 669         crypto_mod_put(poly);
 670         return err;
 671
 672 out_drop_chacha:
 673         crypto_drop_skcipher(&ctx->chacha);
 674 err_drop_poly:
 675         crypto_drop_ahash(&ctx->poly);
 676 err_free_inst:
 677         kfree(inst);
 678         goto out_put_poly;
 679 }
 680
 681 static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
 682 {
 683         return chachapoly_create(tmpl, tb, "rfc7539", 12);
 684 }
 685
 686 static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
 687 {
 688         return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
 689 }
 690
 691 static struct crypto_template rfc7539_tmpls[] = {
 692         {
 693                 .name = "rfc7539",
 694                 .create = rfc7539_create,
 695                 .module = THIS_MODULE,
 696         }, {
 697                 .name = "rfc7539esp",
 698                 .create = rfc7539esp_create,
 699                 .module = THIS_MODULE,
 700         },
 701 };
 702
 703 static int __init chacha20poly1305_module_init(void)
 704 {
 705         return crypto_register_templates(rfc7539_tmpls,
 706                                          ARRAY_SIZE(rfc7539_tmpls));
 707 }
 708
 709 static void __exit chacha20poly1305_module_exit(void)
 710 {
 711         crypto_unregister_templates(rfc7539_tmpls,
 712                                     ARRAY_SIZE(rfc7539_tmpls));
 713 }
 714
 715 subsys_initcall(chacha20poly1305_module_init);
 716 module_exit(chacha20poly1305_module_exit);
 717
 718 MODULE_LICENSE("GPL");
 719 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
 720 MODULE_DESCRIPTION("ChaCha20-Poly1305 AEAD");
 721 MODULE_ALIAS_CRYPTO("rfc7539");
 722 MODULE_ALIAS_CRYPTO("rfc7539esp");