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_ablkcipher *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 ablkcipher_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         union {
  71                 struct poly_req poly;
  72                 struct chacha_req chacha;
  73         } u;
  74 };
  75
  76 static inline void async_done_continue(struct aead_request *req, int err,
  77                                        int (*cont)(struct aead_request *))
  78 {
  79         if (!err)
  80                 err = cont(req);
  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                CHACHA20_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         chacha_iv(creq->iv, req, 1);
 134
 135         sg_init_table(rctx->src, 2);
 136         src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
 137         dst = src;
 138
 139         if (req->src != req->dst) {
 140                 sg_init_table(rctx->dst, 2);
 141                 dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
 142         }
 143
 144         ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
 145                                         chacha_decrypt_done, req);
 146         ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
 147         ablkcipher_request_set_crypt(&creq->req, src, dst,
 148                                      rctx->cryptlen, creq->iv);
 149         err = crypto_ablkcipher_decrypt(&creq->req);
 150         if (err)
 151                 return err;
 152
 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         __le64 len;
 178         int err;
 179
 180         sg_init_table(preq->src, 1);
 181         len = cpu_to_le64(rctx->assoclen);
 182         memcpy(&preq->tail.assoclen, &len, sizeof(len));
 183         len = cpu_to_le64(rctx->cryptlen);
 184         memcpy(&preq->tail.cryptlen, &len, sizeof(len));
 185         sg_set_buf(preq->src, &preq->tail, sizeof(preq->tail));
 186
 187         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 188                                    poly_tail_done, req);
 189         ahash_request_set_tfm(&preq->req, ctx->poly);
 190         ahash_request_set_crypt(&preq->req, preq->src,
 191                                 rctx->tag, sizeof(preq->tail));
 192
 193         err = crypto_ahash_finup(&preq->req);
 194         if (err)
 195                 return err;
 196
 197         return poly_tail_continue(req);
 198 }
 199
 200 static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
 201 {
 202         async_done_continue(areq->data, err, poly_tail);
 203 }
 204
 205 static int poly_cipherpad(struct aead_request *req)
 206 {
 207         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 208         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 209         struct poly_req *preq = &rctx->u.poly;
 210         unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
 211         int err;
 212
 213         padlen = (bs - (rctx->cryptlen % bs)) % bs;
 214         memset(preq->pad, 0, sizeof(preq->pad));
 215         sg_init_table(preq->src, 1);
 216         sg_set_buf(preq->src, &preq->pad, padlen);
 217
 218         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 219                                    poly_cipherpad_done, req);
 220         ahash_request_set_tfm(&preq->req, ctx->poly);
 221         ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
 222
 223         err = crypto_ahash_update(&preq->req);
 224         if (err)
 225                 return err;
 226
 227         return poly_tail(req);
 228 }
 229
 230 static void poly_cipher_done(struct crypto_async_request *areq, int err)
 231 {
 232         async_done_continue(areq->data, err, poly_cipherpad);
 233 }
 234
 235 static int poly_cipher(struct aead_request *req)
 236 {
 237         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 238         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 239         struct poly_req *preq = &rctx->u.poly;
 240         struct scatterlist *crypt = req->src;
 241         int err;
 242
 243         if (rctx->cryptlen == req->cryptlen) /* encrypting */
 244                 crypt = req->dst;
 245
 246         sg_init_table(rctx->src, 2);
 247         crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);
 248
 249         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 250                                    poly_cipher_done, req);
 251         ahash_request_set_tfm(&preq->req, ctx->poly);
 252         ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);
 253
 254         err = crypto_ahash_update(&preq->req);
 255         if (err)
 256                 return err;
 257
 258         return poly_cipherpad(req);
 259 }
 260
 261 static void poly_adpad_done(struct crypto_async_request *areq, int err)
 262 {
 263         async_done_continue(areq->data, err, poly_cipher);
 264 }
 265
 266 static int poly_adpad(struct aead_request *req)
 267 {
 268         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 269         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 270         struct poly_req *preq = &rctx->u.poly;
 271         unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
 272         int err;
 273
 274         padlen = (bs - (rctx->assoclen % bs)) % bs;
 275         memset(preq->pad, 0, sizeof(preq->pad));
 276         sg_init_table(preq->src, 1);
 277         sg_set_buf(preq->src, preq->pad, padlen);
 278
 279         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 280                                    poly_adpad_done, req);
 281         ahash_request_set_tfm(&preq->req, ctx->poly);
 282         ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
 283
 284         err = crypto_ahash_update(&preq->req);
 285         if (err)
 286                 return err;
 287
 288         return poly_cipher(req);
 289 }
 290
 291 static void poly_ad_done(struct crypto_async_request *areq, int err)
 292 {
 293         async_done_continue(areq->data, err, poly_adpad);
 294 }
 295
 296 static int poly_ad(struct aead_request *req)
 297 {
 298         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 299         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 300         struct poly_req *preq = &rctx->u.poly;
 301         int err;
 302
 303         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 304                                    poly_ad_done, req);
 305         ahash_request_set_tfm(&preq->req, ctx->poly);
 306         ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);
 307
 308         err = crypto_ahash_update(&preq->req);
 309         if (err)
 310                 return err;
 311
 312         return poly_adpad(req);
 313 }
 314
 315 static void poly_setkey_done(struct crypto_async_request *areq, int err)
 316 {
 317         async_done_continue(areq->data, err, poly_ad);
 318 }
 319
 320 static int poly_setkey(struct aead_request *req)
 321 {
 322         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 323         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 324         struct poly_req *preq = &rctx->u.poly;
 325         int err;
 326
 327         sg_init_table(preq->src, 1);
 328         sg_set_buf(preq->src, rctx->key, sizeof(rctx->key));
 329
 330         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 331                                    poly_setkey_done, req);
 332         ahash_request_set_tfm(&preq->req, ctx->poly);
 333         ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key));
 334
 335         err = crypto_ahash_update(&preq->req);
 336         if (err)
 337                 return err;
 338
 339         return poly_ad(req);
 340 }
 341
 342 static void poly_init_done(struct crypto_async_request *areq, int err)
 343 {
 344         async_done_continue(areq->data, err, poly_setkey);
 345 }
 346
 347 static int poly_init(struct aead_request *req)
 348 {
 349         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 350         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 351         struct poly_req *preq = &rctx->u.poly;
 352         int err;
 353
 354         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 355                                    poly_init_done, req);
 356         ahash_request_set_tfm(&preq->req, ctx->poly);
 357
 358         err = crypto_ahash_init(&preq->req);
 359         if (err)
 360                 return err;
 361
 362         return poly_setkey(req);
 363 }
 364
 365 static void poly_genkey_done(struct crypto_async_request *areq, int err)
 366 {
 367         async_done_continue(areq->data, err, poly_init);
 368 }
 369
 370 static int poly_genkey(struct aead_request *req)
 371 {
 372         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 373         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 374         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 375         struct chacha_req *creq = &rctx->u.chacha;
 376         int err;
 377
 378         rctx->assoclen = req->assoclen;
 379
 380         if (crypto_aead_ivsize(tfm) == 8) {
 381                 if (rctx->assoclen < 8)
 382                         return -EINVAL;
 383                 rctx->assoclen -= 8;
 384         }
 385
 386         sg_init_table(creq->src, 1);
 387         memset(rctx->key, 0, sizeof(rctx->key));
 388         sg_set_buf(creq->src, rctx->key, sizeof(rctx->key));
 389
 390         chacha_iv(creq->iv, req, 0);
 391
 392         ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
 393                                         poly_genkey_done, req);
 394         ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
 395         ablkcipher_request_set_crypt(&creq->req, creq->src, creq->src,
 396                                      POLY1305_KEY_SIZE, creq->iv);
 397
 398         err = crypto_ablkcipher_decrypt(&creq->req);
 399         if (err)
 400                 return err;
 401
 402         return poly_init(req);
 403 }
 404
 405 static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
 406 {
 407         async_done_continue(areq->data, err, poly_genkey);
 408 }
 409
 410 static int chacha_encrypt(struct aead_request *req)
 411 {
 412         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 413         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 414         struct chacha_req *creq = &rctx->u.chacha;
 415         struct scatterlist *src, *dst;
 416         int err;
 417
 418         chacha_iv(creq->iv, req, 1);
 419
 420         sg_init_table(rctx->src, 2);
 421         src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
 422         dst = src;
 423
 424         if (req->src != req->dst) {
 425                 sg_init_table(rctx->dst, 2);
 426                 dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
 427         }
 428
 429         ablkcipher_request_set_callback(&creq->req, aead_request_flags(req),
 430                                         chacha_encrypt_done, req);
 431         ablkcipher_request_set_tfm(&creq->req, ctx->chacha);
 432         ablkcipher_request_set_crypt(&creq->req, src, dst,
 433                                      req->cryptlen, creq->iv);
 434         err = crypto_ablkcipher_encrypt(&creq->req);
 435         if (err)
 436                 return err;
 437
 438         return poly_genkey(req);
 439 }
 440
 441 static int chachapoly_encrypt(struct aead_request *req)
 442 {
 443         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 444
 445         rctx->cryptlen = req->cryptlen;
 446
 447         /* encrypt call chain:
 448          * - chacha_encrypt/done()
 449          * - poly_genkey/done()
 450          * - poly_init/done()
 451          * - poly_setkey/done()
 452          * - poly_ad/done()
 453          * - poly_adpad/done()
 454          * - poly_cipher/done()
 455          * - poly_cipherpad/done()
 456          * - poly_tail/done/continue()
 457          * - poly_copy_tag()
 458          */
 459         return chacha_encrypt(req);
 460 }
 461
 462 static int chachapoly_decrypt(struct aead_request *req)
 463 {
 464         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 465
 466         rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
 467
 468         /* decrypt call chain:
 469          * - poly_genkey/done()
 470          * - poly_init/done()
 471          * - poly_setkey/done()
 472          * - poly_ad/done()
 473          * - poly_adpad/done()
 474          * - poly_cipher/done()
 475          * - poly_cipherpad/done()
 476          * - poly_tail/done/continue()
 477          * - chacha_decrypt/done()
 478          * - poly_verify_tag()
 479          */
 480         return poly_genkey(req);
 481 }
 482
 483 static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
 484                              unsigned int keylen)
 485 {
 486         struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
 487         int err;
 488
 489         if (keylen != ctx->saltlen + CHACHA20_KEY_SIZE)
 490                 return -EINVAL;
 491
 492         keylen -= ctx->saltlen;
 493         memcpy(ctx->salt, key + keylen, ctx->saltlen);
 494
 495         crypto_ablkcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
 496         crypto_ablkcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
 497                                     CRYPTO_TFM_REQ_MASK);
 498
 499         err = crypto_ablkcipher_setkey(ctx->chacha, key, keylen);
 500         crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctx->chacha) &
 501                               CRYPTO_TFM_RES_MASK);
 502         return err;
 503 }
 504
 505 static int chachapoly_setauthsize(struct crypto_aead *tfm,
 506                                   unsigned int authsize)
 507 {
 508         if (authsize != POLY1305_DIGEST_SIZE)
 509                 return -EINVAL;
 510
 511         return 0;
 512 }
 513
 514 static int chachapoly_init(struct crypto_aead *tfm)
 515 {
 516         struct aead_instance *inst = aead_alg_instance(tfm);
 517         struct chachapoly_instance_ctx *ictx = aead_instance_ctx(inst);
 518         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 519         struct crypto_ablkcipher *chacha;
 520         struct crypto_ahash *poly;
 521         unsigned long align;
 522
 523         poly = crypto_spawn_ahash(&ictx->poly);
 524         if (IS_ERR(poly))
 525                 return PTR_ERR(poly);
 526
 527         chacha = crypto_spawn_skcipher(&ictx->chacha);
 528         if (IS_ERR(chacha)) {
 529                 crypto_free_ahash(poly);
 530                 return PTR_ERR(chacha);
 531         }
 532
 533         ctx->chacha = chacha;
 534         ctx->poly = poly;
 535         ctx->saltlen = ictx->saltlen;
 536
 537         align = crypto_aead_alignmask(tfm);
 538         align &= ~(crypto_tfm_ctx_alignment() - 1);
 539         crypto_aead_set_reqsize(
 540                 tfm,
 541                 align + offsetof(struct chachapoly_req_ctx, u) +
 542                 max(offsetof(struct chacha_req, req) +
 543                     sizeof(struct ablkcipher_request) +
 544                     crypto_ablkcipher_reqsize(chacha),
 545                     offsetof(struct poly_req, req) +
 546                     sizeof(struct ahash_request) +
 547                     crypto_ahash_reqsize(poly)));
 548
 549         return 0;
 550 }
 551
 552 static void chachapoly_exit(struct crypto_aead *tfm)
 553 {
 554         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 555
 556         crypto_free_ahash(ctx->poly);
 557         crypto_free_ablkcipher(ctx->chacha);
 558 }
 559
 560 static void chachapoly_free(struct aead_instance *inst)
 561 {
 562         struct chachapoly_instance_ctx *ctx = aead_instance_ctx(inst);
 563
 564         crypto_drop_skcipher(&ctx->chacha);
 565         crypto_drop_ahash(&ctx->poly);
 566         kfree(inst);
 567 }
 568
 569 static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
 570                              const char *name, unsigned int ivsize)
 571 {
 572         struct crypto_attr_type *algt;
 573         struct aead_instance *inst;
 574         struct crypto_alg *chacha;
 575         struct crypto_alg *poly;
 576         struct hash_alg_common *poly_hash;
 577         struct chachapoly_instance_ctx *ctx;
 578         const char *chacha_name, *poly_name;
 579         int err;
 580
 581         if (ivsize > CHACHAPOLY_IV_SIZE)
 582                 return -EINVAL;
 583
 584         algt = crypto_get_attr_type(tb);
 585         if (IS_ERR(algt))
 586                 return PTR_ERR(algt);
 587
 588         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 589                 return -EINVAL;
 590
 591         chacha_name = crypto_attr_alg_name(tb[1]);
 592         if (IS_ERR(chacha_name))
 593                 return PTR_ERR(chacha_name);
 594         poly_name = crypto_attr_alg_name(tb[2]);
 595         if (IS_ERR(poly_name))
 596                 return PTR_ERR(poly_name);
 597
 598         poly = crypto_find_alg(poly_name, &crypto_ahash_type,
 599                                CRYPTO_ALG_TYPE_HASH,
 600                                CRYPTO_ALG_TYPE_AHASH_MASK);
 601         if (IS_ERR(poly))
 602                 return PTR_ERR(poly);
 603         poly_hash = __crypto_hash_alg_common(poly);
 604
 605         err = -EINVAL;
 606         if (poly_hash->digestsize != POLY1305_DIGEST_SIZE)
 607                 goto out_put_poly;
 608
 609         err = -ENOMEM;
 610         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 611         if (!inst)
 612                 goto out_put_poly;
 613
 614         ctx = aead_instance_ctx(inst);
 615         ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
 616         err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
 617                                       aead_crypto_instance(inst));
 618         if (err)
 619                 goto err_free_inst;
 620
 621         crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
 622         err = crypto_grab_skcipher(&ctx->chacha, chacha_name, 0,
 623                                    crypto_requires_sync(algt->type,
 624                                                         algt->mask));
 625         if (err)
 626                 goto err_drop_poly;
 627
 628         chacha = crypto_skcipher_spawn_alg(&ctx->chacha);
 629
 630         err = -EINVAL;
 631         /* Need 16-byte IV size, including Initial Block Counter value */
 632         if (chacha->cra_ablkcipher.ivsize != CHACHA20_IV_SIZE)
 633                 goto out_drop_chacha;
 634         /* Not a stream cipher? */
 635         if (chacha->cra_blocksize != 1)
 636                 goto out_drop_chacha;
 637
 638         err = -ENAMETOOLONG;
 639         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 640                      "%s(%s,%s)", name, chacha_name,
 641                      poly_name) >= CRYPTO_MAX_ALG_NAME)
 642                 goto out_drop_chacha;
 643         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 644                      "%s(%s,%s)", name, chacha->cra_driver_name,
 645                      poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 646                 goto out_drop_chacha;
 647
 648         inst->alg.base.cra_flags = (chacha->cra_flags | poly->cra_flags) &
 649                                    CRYPTO_ALG_ASYNC;
 650         inst->alg.base.cra_priority = (chacha->cra_priority +
 651                                        poly->cra_priority) / 2;
 652         inst->alg.base.cra_blocksize = 1;
 653         inst->alg.base.cra_alignmask = chacha->cra_alignmask |
 654                                        poly->cra_alignmask;
 655         inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
 656                                      ctx->saltlen;
 657         inst->alg.ivsize = ivsize;
 658         inst->alg.maxauthsize = POLY1305_DIGEST_SIZE;
 659         inst->alg.init = chachapoly_init;
 660         inst->alg.exit = chachapoly_exit;
 661         inst->alg.encrypt = chachapoly_encrypt;
 662         inst->alg.decrypt = chachapoly_decrypt;
 663         inst->alg.setkey = chachapoly_setkey;
 664         inst->alg.setauthsize = chachapoly_setauthsize;
 665
 666         inst->free = chachapoly_free;
 667
 668         err = aead_register_instance(tmpl, inst);
 669         if (err)
 670                 goto out_drop_chacha;
 671
 672 out_put_poly:
 673         crypto_mod_put(poly);
 674         return err;
 675
 676 out_drop_chacha:
 677         crypto_drop_skcipher(&ctx->chacha);
 678 err_drop_poly:
 679         crypto_drop_ahash(&ctx->poly);
 680 err_free_inst:
 681         kfree(inst);
 682         goto out_put_poly;
 683 }
 684
 685 static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
 686 {
 687         return chachapoly_create(tmpl, tb, "rfc7539", 12);
 688 }
 689
 690 static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
 691 {
 692         return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
 693 }
 694
 695 static struct crypto_template rfc7539_tmpl = {
 696         .name = "rfc7539",
 697         .create = rfc7539_create,
 698         .module = THIS_MODULE,
 699 };
 700
 701 static struct crypto_template rfc7539esp_tmpl = {
 702         .name = "rfc7539esp",
 703         .create = rfc7539esp_create,
 704         .module = THIS_MODULE,
 705 };
 706
 707 static int __init chacha20poly1305_module_init(void)
 708 {
 709         int err;
 710
 711         err = crypto_register_template(&rfc7539_tmpl);
 712         if (err)
 713                 return err;
 714
 715         err = crypto_register_template(&rfc7539esp_tmpl);
 716         if (err)
 717                 crypto_unregister_template(&rfc7539_tmpl);
 718
 719         return err;
 720 }
 721
 722 static void __exit chacha20poly1305_module_exit(void)
 723 {
 724         crypto_unregister_template(&rfc7539esp_tmpl);
 725         crypto_unregister_template(&rfc7539_tmpl);
 726 }
 727
 728 module_init(chacha20poly1305_module_init);
 729 module_exit(chacha20poly1305_module_exit);
 730
 731 MODULE_LICENSE("GPL");
 732 MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
 733 MODULE_DESCRIPTION("ChaCha20-Poly1305 AEAD");
 734 MODULE_ALIAS_CRYPTO("rfc7539");
 735 MODULE_ALIAS_CRYPTO("rfc7539esp");