crypto/chacha20poly1305.c

   1 /*
   2  * ChaCha20-Poly1305 AEAD, RFC7539
   3  *
   4  * Copyright (C) 2015 Martin Willi
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  */
  11
  12 #include <crypto/internal/aead.h>
  13 #include <crypto/internal/hash.h>
  14 #include <crypto/internal/skcipher.h>
  15 #include <crypto/scatterwalk.h>
  16 #include <crypto/chacha20.h>
  17 #include <crypto/poly1305.h>
  18 #include <linux/err.h>
  19 #include <linux/init.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22
  23 #include "internal.h"
  24
  25 #define CHACHAPOLY_IV_SIZE      12
  26
  27 struct chachapoly_instance_ctx {
  28         struct crypto_skcipher_spawn chacha;
  29         struct crypto_ahash_spawn poly;
  30         unsigned int saltlen;
  31 };
  32
  33 struct chachapoly_ctx {
  34         struct crypto_skcipher *chacha;
  35         struct crypto_ahash *poly;
  36         /* key bytes we use for the ChaCha20 IV */
  37         unsigned int saltlen;
  38         u8 salt[];
  39 };
  40
  41 struct poly_req {
  42         /* zero byte padding for AD/ciphertext, as needed */
  43         u8 pad[POLY1305_BLOCK_SIZE];
  44         /* tail data with AD/ciphertext lengths */
  45         struct {
  46                 __le64 assoclen;
  47                 __le64 cryptlen;
  48         } tail;
  49         struct scatterlist src[1];
  50         struct ahash_request req; /* must be last member */
  51 };
  52
  53 struct chacha_req {
  54         u8 iv[CHACHA20_IV_SIZE];
  55         struct scatterlist src[1];
  56         struct skcipher_request req; /* must be last member */
  57 };
  58
  59 struct chachapoly_req_ctx {
  60         struct scatterlist src[2];
  61         struct scatterlist dst[2];
  62         /* the key we generate for Poly1305 using Chacha20 */
  63         u8 key[POLY1305_KEY_SIZE];
  64         /* calculated Poly1305 tag */
  65         u8 tag[POLY1305_DIGEST_SIZE];
  66         /* length of data to en/decrypt, without ICV */
  67         unsigned int cryptlen;
  68         /* Actual AD, excluding IV */
  69         unsigned int assoclen;
  70         /* request flags, with MAY_SLEEP cleared if needed */
  71         u32 flags;
  72         union {
  73                 struct poly_req poly;
  74                 struct chacha_req chacha;
  75         } u;
  76 };
  77
  78 static inline void async_done_continue(struct aead_request *req, int err,
  79                                        int (*cont)(struct aead_request *))
  80 {
  81         if (!err) {
  82                 struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
  83
  84                 rctx->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
  85                 err = cont(req);
  86         }
  87
  88         if (err != -EINPROGRESS && err != -EBUSY)
  89                 aead_request_complete(req, err);
  90 }
  91
  92 static void chacha_iv(u8 *iv, struct aead_request *req, u32 icb)
  93 {
  94         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
  95         __le32 leicb = cpu_to_le32(icb);
  96
  97         memcpy(iv, &leicb, sizeof(leicb));
  98         memcpy(iv + sizeof(leicb), ctx->salt, ctx->saltlen);
  99         memcpy(iv + sizeof(leicb) + ctx->saltlen, req->iv,
 100                CHACHA20_IV_SIZE - sizeof(leicb) - ctx->saltlen);
 101 }
 102
 103 static int poly_verify_tag(struct aead_request *req)
 104 {
 105         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 106         u8 tag[sizeof(rctx->tag)];
 107
 108         scatterwalk_map_and_copy(tag, req->src,
 109                                  req->assoclen + rctx->cryptlen,
 110                                  sizeof(tag), 0);
 111         if (crypto_memneq(tag, rctx->tag, sizeof(tag)))
 112                 return -EBADMSG;
 113         return 0;
 114 }
 115
 116 static int poly_copy_tag(struct aead_request *req)
 117 {
 118         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 119
 120         scatterwalk_map_and_copy(rctx->tag, req->dst,
 121                                  req->assoclen + rctx->cryptlen,
 122                                  sizeof(rctx->tag), 1);
 123         return 0;
 124 }
 125
 126 static void chacha_decrypt_done(struct crypto_async_request *areq, int err)
 127 {
 128         async_done_continue(areq->data, err, poly_verify_tag);
 129 }
 130
 131 static int chacha_decrypt(struct aead_request *req)
 132 {
 133         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 134         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 135         struct chacha_req *creq = &rctx->u.chacha;
 136         struct scatterlist *src, *dst;
 137         int err;
 138
 139         if (rctx->cryptlen == 0)
 140                 goto skip;
 141
 142         chacha_iv(creq->iv, req, 1);
 143
 144         sg_init_table(rctx->src, 2);
 145         src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
 146         dst = src;
 147
 148         if (req->src != req->dst) {
 149                 sg_init_table(rctx->dst, 2);
 150                 dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
 151         }
 152
 153         skcipher_request_set_callback(&creq->req, rctx->flags,
 154                                       chacha_decrypt_done, req);
 155         skcipher_request_set_tfm(&creq->req, ctx->chacha);
 156         skcipher_request_set_crypt(&creq->req, src, dst,
 157                                    rctx->cryptlen, creq->iv);
 158         err = crypto_skcipher_decrypt(&creq->req);
 159         if (err)
 160                 return err;
 161
 162 skip:
 163         return poly_verify_tag(req);
 164 }
 165
 166 static int poly_tail_continue(struct aead_request *req)
 167 {
 168         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 169
 170         if (rctx->cryptlen == req->cryptlen) /* encrypting */
 171                 return poly_copy_tag(req);
 172
 173         return chacha_decrypt(req);
 174 }
 175
 176 static void poly_tail_done(struct crypto_async_request *areq, int err)
 177 {
 178         async_done_continue(areq->data, err, poly_tail_continue);
 179 }
 180
 181 static int poly_tail(struct aead_request *req)
 182 {
 183         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 184         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 185         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 186         struct poly_req *preq = &rctx->u.poly;
 187         __le64 len;
 188         int err;
 189
 190         sg_init_table(preq->src, 1);
 191         len = cpu_to_le64(rctx->assoclen);
 192         memcpy(&preq->tail.assoclen, &len, sizeof(len));
 193         len = cpu_to_le64(rctx->cryptlen);
 194         memcpy(&preq->tail.cryptlen, &len, sizeof(len));
 195         sg_set_buf(preq->src, &preq->tail, sizeof(preq->tail));
 196
 197         ahash_request_set_callback(&preq->req, rctx->flags,
 198                                    poly_tail_done, req);
 199         ahash_request_set_tfm(&preq->req, ctx->poly);
 200         ahash_request_set_crypt(&preq->req, preq->src,
 201                                 rctx->tag, sizeof(preq->tail));
 202
 203         err = crypto_ahash_finup(&preq->req);
 204         if (err)
 205                 return err;
 206
 207         return poly_tail_continue(req);
 208 }
 209
 210 static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
 211 {
 212         async_done_continue(areq->data, err, poly_tail);
 213 }
 214
 215 static int poly_cipherpad(struct aead_request *req)
 216 {
 217         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 218         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 219         struct poly_req *preq = &rctx->u.poly;
 220         unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
 221         int err;
 222
 223         padlen = (bs - (rctx->cryptlen % bs)) % bs;
 224         memset(preq->pad, 0, sizeof(preq->pad));
 225         sg_init_table(preq->src, 1);
 226         sg_set_buf(preq->src, &preq->pad, padlen);
 227
 228         ahash_request_set_callback(&preq->req, rctx->flags,
 229                                    poly_cipherpad_done, req);
 230         ahash_request_set_tfm(&preq->req, ctx->poly);
 231         ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
 232
 233         err = crypto_ahash_update(&preq->req);
 234         if (err)
 235                 return err;
 236
 237         return poly_tail(req);
 238 }
 239
 240 static void poly_cipher_done(struct crypto_async_request *areq, int err)
 241 {
 242         async_done_continue(areq->data, err, poly_cipherpad);
 243 }
 244
 245 static int poly_cipher(struct aead_request *req)
 246 {
 247         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 248         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 249         struct poly_req *preq = &rctx->u.poly;
 250         struct scatterlist *crypt = req->src;
 251         int err;
 252
 253         if (rctx->cryptlen == req->cryptlen) /* encrypting */
 254                 crypt = req->dst;
 255
 256         sg_init_table(rctx->src, 2);
 257         crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);
 258
 259         ahash_request_set_callback(&preq->req, rctx->flags,
 260                                    poly_cipher_done, req);
 261         ahash_request_set_tfm(&preq->req, ctx->poly);
 262         ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);
 263
 264         err = crypto_ahash_update(&preq->req);
 265         if (err)
 266                 return err;
 267
 268         return poly_cipherpad(req);
 269 }
 270
 271 static void poly_adpad_done(struct crypto_async_request *areq, int err)
 272 {
 273         async_done_continue(areq->data, err, poly_cipher);
 274 }
 275
 276 static int poly_adpad(struct aead_request *req)
 277 {
 278         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 279         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 280         struct poly_req *preq = &rctx->u.poly;
 281         unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
 282         int err;
 283
 284         padlen = (bs - (rctx->assoclen % bs)) % bs;
 285         memset(preq->pad, 0, sizeof(preq->pad));
 286         sg_init_table(preq->src, 1);
 287         sg_set_buf(preq->src, preq->pad, padlen);
 288
 289         ahash_request_set_callback(&preq->req, rctx->flags,
 290                                    poly_adpad_done, req);
 291         ahash_request_set_tfm(&preq->req, ctx->poly);
 292         ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
 293
 294         err = crypto_ahash_update(&preq->req);
 295         if (err)
 296                 return err;
 297
 298         return poly_cipher(req);
 299 }
 300
 301 static void poly_ad_done(struct crypto_async_request *areq, int err)
 302 {
 303         async_done_continue(areq->data, err, poly_adpad);
 304 }
 305
 306 static int poly_ad(struct aead_request *req)
 307 {
 308         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 309         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 310         struct poly_req *preq = &rctx->u.poly;
 311         int err;
 312
 313         ahash_request_set_callback(&preq->req, rctx->flags,
 314                                    poly_ad_done, req);
 315         ahash_request_set_tfm(&preq->req, ctx->poly);
 316         ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);
 317
 318         err = crypto_ahash_update(&preq->req);
 319         if (err)
 320                 return err;
 321
 322         return poly_adpad(req);
 323 }
 324
 325 static void poly_setkey_done(struct crypto_async_request *areq, int err)
 326 {
 327         async_done_continue(areq->data, err, poly_ad);
 328 }
 329
 330 static int poly_setkey(struct aead_request *req)
 331 {
 332         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 333         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 334         struct poly_req *preq = &rctx->u.poly;
 335         int err;
 336
 337         sg_init_table(preq->src, 1);
 338         sg_set_buf(preq->src, rctx->key, sizeof(rctx->key));
 339
 340         ahash_request_set_callback(&preq->req, rctx->flags,
 341                                    poly_setkey_done, req);
 342         ahash_request_set_tfm(&preq->req, ctx->poly);
 343         ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key));
 344
 345         err = crypto_ahash_update(&preq->req);
 346         if (err)
 347                 return err;
 348
 349         return poly_ad(req);
 350 }
 351
 352 static void poly_init_done(struct crypto_async_request *areq, int err)
 353 {
 354         async_done_continue(areq->data, err, poly_setkey);
 355 }
 356
 357 static int poly_init(struct aead_request *req)
 358 {
 359         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 360         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 361         struct poly_req *preq = &rctx->u.poly;
 362         int err;
 363
 364         ahash_request_set_callback(&preq->req, rctx->flags,
 365                                    poly_init_done, req);
 366         ahash_request_set_tfm(&preq->req, ctx->poly);
 367
 368         err = crypto_ahash_init(&preq->req);
 369         if (err)
 370                 return err;
 371
 372         return poly_setkey(req);
 373 }
 374
 375 static void poly_genkey_done(struct crypto_async_request *areq, int err)
 376 {
 377         async_done_continue(areq->data, err, poly_init);
 378 }
 379
 380 static int poly_genkey(struct aead_request *req)
 381 {
 382         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 383         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 384         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 385         struct chacha_req *creq = &rctx->u.chacha;
 386         int err;
 387
 388         rctx->assoclen = req->assoclen;
 389
 390         if (crypto_aead_ivsize(tfm) == 8) {
 391                 if (rctx->assoclen < 8)
 392                         return -EINVAL;
 393                 rctx->assoclen -= 8;
 394         }
 395
 396         sg_init_table(creq->src, 1);
 397         memset(rctx->key, 0, sizeof(rctx->key));
 398         sg_set_buf(creq->src, rctx->key, sizeof(rctx->key));
 399
 400         chacha_iv(creq->iv, req, 0);
 401
 402         skcipher_request_set_callback(&creq->req, rctx->flags,
 403                                       poly_genkey_done, req);
 404         skcipher_request_set_tfm(&creq->req, ctx->chacha);
 405         skcipher_request_set_crypt(&creq->req, creq->src, creq->src,
 406                                    POLY1305_KEY_SIZE, creq->iv);
 407
 408         err = crypto_skcipher_decrypt(&creq->req);
 409         if (err)
 410                 return err;
 411
 412         return poly_init(req);
 413 }
 414
 415 static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
 416 {
 417         async_done_continue(areq->data, err, poly_genkey);
 418 }
 419
 420 static int chacha_encrypt(struct aead_request *req)
 421 {
 422         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 423         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 424         struct chacha_req *creq = &rctx->u.chacha;
 425         struct scatterlist *src, *dst;
 426         int err;
 427
 428         if (req->cryptlen == 0)
 429                 goto skip;
 430
 431         chacha_iv(creq->iv, req, 1);
 432
 433         sg_init_table(rctx->src, 2);
 434         src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
 435         dst = src;
 436
 437         if (req->src != req->dst) {
 438                 sg_init_table(rctx->dst, 2);
 439                 dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
 440         }
 441
 442         skcipher_request_set_callback(&creq->req, rctx->flags,
 443                                       chacha_encrypt_done, req);
 444         skcipher_request_set_tfm(&creq->req, ctx->chacha);
 445         skcipher_request_set_crypt(&creq->req, src, dst,
 446                                    req->cryptlen, creq->iv);
 447         err = crypto_skcipher_encrypt(&creq->req);
 448         if (err)
 449                 return err;
 450
 451 skip:
 452         return poly_genkey(req);
 453 }
 454
 455 static int chachapoly_encrypt(struct aead_request *req)
 456 {
 457         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 458
 459         rctx->cryptlen = req->cryptlen;
 460         rctx->flags = aead_request_flags(req);
 461
 462         /* encrypt call chain:
 463          * - chacha_encrypt/done()
 464          * - poly_genkey/done()
 465          * - poly_init/done()
 466          * - poly_setkey/done()
 467          * - poly_ad/done()
 468          * - poly_adpad/done()
 469          * - poly_cipher/done()
 470          * - poly_cipherpad/done()
 471          * - poly_tail/done/continue()
 472          * - poly_copy_tag()
 473          */
 474         return chacha_encrypt(req);
 475 }
 476
 477 static int chachapoly_decrypt(struct aead_request *req)
 478 {
 479         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 480
 481         rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
 482         rctx->flags = aead_request_flags(req);
 483
 484         /* decrypt call chain:
 485          * - poly_genkey/done()
 486          * - poly_init/done()
 487          * - poly_setkey/done()
 488          * - poly_ad/done()
 489          * - poly_adpad/done()
 490          * - poly_cipher/done()
 491          * - poly_cipherpad/done()
 492          * - poly_tail/done/continue()
 493          * - chacha_decrypt/done()
 494          * - poly_verify_tag()
 495          */
 496         return poly_genkey(req);
 497 }
 498
 499 static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
 500                              unsigned int keylen)
 501 {
 502         struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
 503         int err;
 504
 505         if (keylen != ctx->saltlen + CHACHA20_KEY_SIZE)
 506                 return -EINVAL;
 507
 508         keylen -= ctx->saltlen;
 509         memcpy(ctx->salt, key + keylen, ctx->saltlen);
 510
 511         crypto_skcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
 512         crypto_skcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
 513                                                CRYPTO_TFM_REQ_MASK);
 514
 515         err = crypto_skcipher_setkey(ctx->chacha, key, keylen);
 516         crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctx->chacha) &
 517                                     CRYPTO_TFM_RES_MASK);
 518         return err;
 519 }
 520
 521 static int chachapoly_setauthsize(struct crypto_aead *tfm,
 522                                   unsigned int authsize)
 523 {
 524         if (authsize != POLY1305_DIGEST_SIZE)
 525                 return -EINVAL;
 526
 527         return 0;
 528 }
 529
 530 static int chachapoly_init(struct crypto_aead *tfm)
 531 {
 532         struct aead_instance *inst = aead_alg_instance(tfm);
 533         struct chachapoly_instance_ctx *ictx = aead_instance_ctx(inst);
 534         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 535         struct crypto_skcipher *chacha;
 536         struct crypto_ahash *poly;
 537         unsigned long align;
 538
 539         poly = crypto_spawn_ahash(&ictx->poly);
 540         if (IS_ERR(poly))
 541                 return PTR_ERR(poly);
 542
 543         chacha = crypto_spawn_skcipher2(&ictx->chacha);
 544         if (IS_ERR(chacha)) {
 545                 crypto_free_ahash(poly);
 546                 return PTR_ERR(chacha);
 547         }
 548
 549         ctx->chacha = chacha;
 550         ctx->poly = poly;
 551         ctx->saltlen = ictx->saltlen;
 552
 553         align = crypto_aead_alignmask(tfm);
 554         align &= ~(crypto_tfm_ctx_alignment() - 1);
 555         crypto_aead_set_reqsize(
 556                 tfm,
 557                 align + offsetof(struct chachapoly_req_ctx, u) +
 558                 max(offsetof(struct chacha_req, req) +
 559                     sizeof(struct skcipher_request) +
 560                     crypto_skcipher_reqsize(chacha),
 561                     offsetof(struct poly_req, req) +
 562                     sizeof(struct ahash_request) +
 563                     crypto_ahash_reqsize(poly)));
 564
 565         return 0;
 566 }
 567
 568 static void chachapoly_exit(struct crypto_aead *tfm)
 569 {
 570         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 571
 572         crypto_free_ahash(ctx->poly);
 573         crypto_free_skcipher(ctx->chacha);
 574 }
 575
 576 static void chachapoly_free(struct aead_instance *inst)
 577 {
 578         struct chachapoly_instance_ctx *ctx = aead_instance_ctx(inst);
 579
 580         crypto_drop_skcipher(&ctx->chacha);
 581         crypto_drop_ahash(&ctx->poly);
 582         kfree(inst);
 583 }
 584
 585 static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
 586                              const char *name, unsigned int ivsize)
 587 {
 588         struct crypto_attr_type *algt;
 589         struct aead_instance *inst;
 590         struct skcipher_alg *chacha;
 591         struct crypto_alg *poly;
 592         struct hash_alg_common *poly_hash;
 593         struct chachapoly_instance_ctx *ctx;
 594         const char *chacha_name, *poly_name;
 595         int err;
 596
 597         if (ivsize > CHACHAPOLY_IV_SIZE)
 598                 return -EINVAL;
 599
 600         algt = crypto_get_attr_type(tb);
 601         if (IS_ERR(algt))
 602                 return PTR_ERR(algt);
 603
 604         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 605                 return -EINVAL;
 606
 607         chacha_name = crypto_attr_alg_name(tb[1]);
 608         if (IS_ERR(chacha_name))
 609                 return PTR_ERR(chacha_name);
 610         poly_name = crypto_attr_alg_name(tb[2]);
 611         if (IS_ERR(poly_name))
 612                 return PTR_ERR(poly_name);
 613
 614         poly = crypto_find_alg(poly_name, &crypto_ahash_type,
 615                                CRYPTO_ALG_TYPE_HASH,
 616                                CRYPTO_ALG_TYPE_AHASH_MASK |
 617                                crypto_requires_sync(algt->type,
 618                                                     algt->mask));
 619         if (IS_ERR(poly))
 620                 return PTR_ERR(poly);
 621         poly_hash = __crypto_hash_alg_common(poly);
 622
 623         err = -EINVAL;
 624         if (poly_hash->digestsize != POLY1305_DIGEST_SIZE)
 625                 goto out_put_poly;
 626
 627         err = -ENOMEM;
 628         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 629         if (!inst)
 630                 goto out_put_poly;
 631
 632         ctx = aead_instance_ctx(inst);
 633         ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
 634         err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
 635                                       aead_crypto_instance(inst));
 636         if (err)
 637                 goto err_free_inst;
 638
 639         crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
 640         err = crypto_grab_skcipher2(&ctx->chacha, chacha_name, 0,
 641                                     crypto_requires_sync(algt->type,
 642                                                          algt->mask));
 643         if (err)
 644                 goto err_drop_poly;
 645
 646         chacha = crypto_spawn_skcipher_alg(&ctx->chacha);
 647
 648         err = -EINVAL;
 649         /* Need 16-byte IV size, including Initial Block Counter value */
 650         if (crypto_skcipher_alg_ivsize(chacha) != CHACHA20_IV_SIZE)
 651                 goto out_drop_chacha;
 652         /* Not a stream cipher? */
 653         if (chacha->base.cra_blocksize != 1)
 654                 goto out_drop_chacha;
 655
 656         err = -ENAMETOOLONG;
 657         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 658                      "%s(%s,%s)", name, chacha->base.cra_name,
 659                      poly->cra_name) >= CRYPTO_MAX_ALG_NAME)
 660                 goto out_drop_chacha;
 661         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 662                      "%s(%s,%s)", name, chacha->base.cra_driver_name,
 663                      poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 664                 goto out_drop_chacha;
 665
 666         inst->alg.base.cra_flags = (chacha->base.cra_flags | poly->cra_flags) &
 667                                    CRYPTO_ALG_ASYNC;
 668         inst->alg.base.cra_priority = (chacha->base.cra_priority +
 669                                        poly->cra_priority) / 2;
 670         inst->alg.base.cra_blocksize = 1;
 671         inst->alg.base.cra_alignmask = chacha->base.cra_alignmask |
 672                                        poly->cra_alignmask;
 673         inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
 674                                      ctx->saltlen;
 675         inst->alg.ivsize = ivsize;
 676         inst->alg.chunksize = crypto_skcipher_alg_chunksize(chacha);
 677         inst->alg.maxauthsize = POLY1305_DIGEST_SIZE;
 678         inst->alg.init = chachapoly_init;
 679         inst->alg.exit = chachapoly_exit;
 680         inst->alg.encrypt = chachapoly_encrypt;
 681         inst->alg.decrypt = chachapoly_decrypt;
 682         inst->alg.setkey = chachapoly_setkey;
 683         inst->alg.setauthsize = chachapoly_setauthsize;
 684
 685         inst->free = chachapoly_free;
 686
 687         err = aead_register_instance(tmpl, inst);
 688         if (err)
 689                 goto out_drop_chacha;
 690
 691 out_put_poly:
 692         crypto_mod_put(poly);
 693         return err;
 694
 695 out_drop_chacha:
 696         crypto_drop_skcipher(&ctx->chacha);
 697 err_drop_poly:
 698         crypto_drop_ahash(&ctx->poly);
 699 err_free_inst:
 700         kfree(inst);
 701         goto out_put_poly;
 702 }
 703
 704 static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
 705 {
 706         return chachapoly_create(tmpl, tb, "rfc7539", 12);
 707 }
 708
 709 static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
 710 {
 711         return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
 712 }
 713
 714 static struct crypto_template rfc7539_tmpl = {
 715         .name = "rfc7539",
 716         .create = rfc7539_create,
 717         .module = THIS_MODULE,
 718 };
 719
 720 static struct crypto_template rfc7539esp_tmpl = {
 721         .name = "rfc7539esp",
 722         .create = rfc7539esp_create,
 723         .module = THIS_MODULE,
 724 };
 725
 726 static int __init chacha20poly1305_module_init(void)
 727 {
 728         int err;
 729
 730         err = crypto_register_template(&rfc7539_tmpl);
 731         if (err)
 732                 return err;
 733
 734         err = crypto_register_template(&rfc7539esp_tmpl);
 735         if (err)
 736                 crypto_unregister_template(&rfc7539_tmpl);
 737
 738         return err;
 739 }
 740
 741 static void __exit chacha20poly1305_module_exit(void)
 742 {
 743         crypto_unregister_template(&rfc7539esp_tmpl);
 744         crypto_unregister_template(&rfc7539_tmpl);
 745 }
 746
 747 module_init(chacha20poly1305_module_init);
 748 module_exit(chacha20poly1305_module_exit);
 749
 750 MODULE_LICENSE("GPL");
 751 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
 752 MODULE_DESCRIPTION("ChaCha20-Poly1305 AEAD");
 753 MODULE_ALIAS_CRYPTO("rfc7539");
 754 MODULE_ALIAS_CRYPTO("rfc7539esp");