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/chacha.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 struct chachapoly_instance_ctx {
  26         struct crypto_skcipher_spawn chacha;
  27         struct crypto_ahash_spawn poly;
  28         unsigned int saltlen;
  29 };
  30
  31 struct chachapoly_ctx {
  32         struct crypto_skcipher *chacha;
  33         struct crypto_ahash *poly;
  34         /* key bytes we use for the ChaCha20 IV */
  35         unsigned int saltlen;
  36         u8 salt[];
  37 };
  38
  39 struct poly_req {
  40         /* zero byte padding for AD/ciphertext, as needed */
  41         u8 pad[POLY1305_BLOCK_SIZE];
  42         /* tail data with AD/ciphertext lengths */
  43         struct {
  44                 __le64 assoclen;
  45                 __le64 cryptlen;
  46         } tail;
  47         struct scatterlist src[1];
  48         struct ahash_request req; /* must be last member */
  49 };
  50
  51 struct chacha_req {
  52         u8 iv[CHACHA_IV_SIZE];
  53         struct scatterlist src[1];
  54         struct skcipher_request req; /* must be last member */
  55 };
  56
  57 struct chachapoly_req_ctx {
  58         struct scatterlist src[2];
  59         struct scatterlist dst[2];
  60         /* the key we generate for Poly1305 using Chacha20 */
  61         u8 key[POLY1305_KEY_SIZE];
  62         /* calculated Poly1305 tag */
  63         u8 tag[POLY1305_DIGEST_SIZE];
  64         /* length of data to en/decrypt, without ICV */
  65         unsigned int cryptlen;
  66         /* Actual AD, excluding IV */
  67         unsigned int assoclen;
  68         union {
  69                 struct poly_req poly;
  70                 struct chacha_req chacha;
  71         } u;
  72 };
  73
  74 static inline void async_done_continue(struct aead_request *req, int err,
  75                                        int (*cont)(struct aead_request *))
  76 {
  77         if (!err)
  78                 err = cont(req);
  79
  80         if (err != -EINPROGRESS && err != -EBUSY)
  81                 aead_request_complete(req, err);
  82 }
  83
  84 static void chacha_iv(u8 *iv, struct aead_request *req, u32 icb)
  85 {
  86         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
  87         __le32 leicb = cpu_to_le32(icb);
  88
  89         memcpy(iv, &leicb, sizeof(leicb));
  90         memcpy(iv + sizeof(leicb), ctx->salt, ctx->saltlen);
  91         memcpy(iv + sizeof(leicb) + ctx->saltlen, req->iv,
  92                CHACHA_IV_SIZE - sizeof(leicb) - ctx->saltlen);
  93 }
  94
  95 static int poly_verify_tag(struct aead_request *req)
  96 {
  97         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
  98         u8 tag[sizeof(rctx->tag)];
  99
 100         scatterwalk_map_and_copy(tag, req->src,
 101                                  req->assoclen + rctx->cryptlen,
 102                                  sizeof(tag), 0);
 103         if (crypto_memneq(tag, rctx->tag, sizeof(tag)))
 104                 return -EBADMSG;
 105         return 0;
 106 }
 107
 108 static int poly_copy_tag(struct aead_request *req)
 109 {
 110         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 111
 112         scatterwalk_map_and_copy(rctx->tag, req->dst,
 113                                  req->assoclen + rctx->cryptlen,
 114                                  sizeof(rctx->tag), 1);
 115         return 0;
 116 }
 117
 118 static void chacha_decrypt_done(struct crypto_async_request *areq, int err)
 119 {
 120         async_done_continue(areq->data, err, poly_verify_tag);
 121 }
 122
 123 static int chacha_decrypt(struct aead_request *req)
 124 {
 125         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 126         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 127         struct chacha_req *creq = &rctx->u.chacha;
 128         struct scatterlist *src, *dst;
 129         int err;
 130
 131         if (rctx->cryptlen == 0)
 132                 goto skip;
 133
 134         chacha_iv(creq->iv, req, 1);
 135
 136         sg_init_table(rctx->src, 2);
 137         src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
 138         dst = src;
 139
 140         if (req->src != req->dst) {
 141                 sg_init_table(rctx->dst, 2);
 142                 dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
 143         }
 144
 145         skcipher_request_set_callback(&creq->req, aead_request_flags(req),
 146                                       chacha_decrypt_done, req);
 147         skcipher_request_set_tfm(&creq->req, ctx->chacha);
 148         skcipher_request_set_crypt(&creq->req, src, dst,
 149                                    rctx->cryptlen, creq->iv);
 150         err = crypto_skcipher_decrypt(&creq->req);
 151         if (err)
 152                 return err;
 153
 154 skip:
 155         return poly_verify_tag(req);
 156 }
 157
 158 static int poly_tail_continue(struct aead_request *req)
 159 {
 160         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 161
 162         if (rctx->cryptlen == req->cryptlen) /* encrypting */
 163                 return poly_copy_tag(req);
 164
 165         return chacha_decrypt(req);
 166 }
 167
 168 static void poly_tail_done(struct crypto_async_request *areq, int err)
 169 {
 170         async_done_continue(areq->data, err, poly_tail_continue);
 171 }
 172
 173 static int poly_tail(struct aead_request *req)
 174 {
 175         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 176         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 177         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 178         struct poly_req *preq = &rctx->u.poly;
 179         __le64 len;
 180         int err;
 181
 182         sg_init_table(preq->src, 1);
 183         len = cpu_to_le64(rctx->assoclen);
 184         memcpy(&preq->tail.assoclen, &len, sizeof(len));
 185         len = cpu_to_le64(rctx->cryptlen);
 186         memcpy(&preq->tail.cryptlen, &len, sizeof(len));
 187         sg_set_buf(preq->src, &preq->tail, sizeof(preq->tail));
 188
 189         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 190                                    poly_tail_done, req);
 191         ahash_request_set_tfm(&preq->req, ctx->poly);
 192         ahash_request_set_crypt(&preq->req, preq->src,
 193                                 rctx->tag, sizeof(preq->tail));
 194
 195         err = crypto_ahash_finup(&preq->req);
 196         if (err)
 197                 return err;
 198
 199         return poly_tail_continue(req);
 200 }
 201
 202 static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
 203 {
 204         async_done_continue(areq->data, err, poly_tail);
 205 }
 206
 207 static int poly_cipherpad(struct aead_request *req)
 208 {
 209         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 210         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 211         struct poly_req *preq = &rctx->u.poly;
 212         unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
 213         int err;
 214
 215         padlen = (bs - (rctx->cryptlen % bs)) % bs;
 216         memset(preq->pad, 0, sizeof(preq->pad));
 217         sg_init_table(preq->src, 1);
 218         sg_set_buf(preq->src, &preq->pad, padlen);
 219
 220         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 221                                    poly_cipherpad_done, req);
 222         ahash_request_set_tfm(&preq->req, ctx->poly);
 223         ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
 224
 225         err = crypto_ahash_update(&preq->req);
 226         if (err)
 227                 return err;
 228
 229         return poly_tail(req);
 230 }
 231
 232 static void poly_cipher_done(struct crypto_async_request *areq, int err)
 233 {
 234         async_done_continue(areq->data, err, poly_cipherpad);
 235 }
 236
 237 static int poly_cipher(struct aead_request *req)
 238 {
 239         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 240         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 241         struct poly_req *preq = &rctx->u.poly;
 242         struct scatterlist *crypt = req->src;
 243         int err;
 244
 245         if (rctx->cryptlen == req->cryptlen) /* encrypting */
 246                 crypt = req->dst;
 247
 248         sg_init_table(rctx->src, 2);
 249         crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);
 250
 251         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 252                                    poly_cipher_done, req);
 253         ahash_request_set_tfm(&preq->req, ctx->poly);
 254         ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);
 255
 256         err = crypto_ahash_update(&preq->req);
 257         if (err)
 258                 return err;
 259
 260         return poly_cipherpad(req);
 261 }
 262
 263 static void poly_adpad_done(struct crypto_async_request *areq, int err)
 264 {
 265         async_done_continue(areq->data, err, poly_cipher);
 266 }
 267
 268 static int poly_adpad(struct aead_request *req)
 269 {
 270         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 271         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 272         struct poly_req *preq = &rctx->u.poly;
 273         unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
 274         int err;
 275
 276         padlen = (bs - (rctx->assoclen % bs)) % bs;
 277         memset(preq->pad, 0, sizeof(preq->pad));
 278         sg_init_table(preq->src, 1);
 279         sg_set_buf(preq->src, preq->pad, padlen);
 280
 281         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 282                                    poly_adpad_done, req);
 283         ahash_request_set_tfm(&preq->req, ctx->poly);
 284         ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
 285
 286         err = crypto_ahash_update(&preq->req);
 287         if (err)
 288                 return err;
 289
 290         return poly_cipher(req);
 291 }
 292
 293 static void poly_ad_done(struct crypto_async_request *areq, int err)
 294 {
 295         async_done_continue(areq->data, err, poly_adpad);
 296 }
 297
 298 static int poly_ad(struct aead_request *req)
 299 {
 300         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 301         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 302         struct poly_req *preq = &rctx->u.poly;
 303         int err;
 304
 305         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 306                                    poly_ad_done, req);
 307         ahash_request_set_tfm(&preq->req, ctx->poly);
 308         ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);
 309
 310         err = crypto_ahash_update(&preq->req);
 311         if (err)
 312                 return err;
 313
 314         return poly_adpad(req);
 315 }
 316
 317 static void poly_setkey_done(struct crypto_async_request *areq, int err)
 318 {
 319         async_done_continue(areq->data, err, poly_ad);
 320 }
 321
 322 static int poly_setkey(struct aead_request *req)
 323 {
 324         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 325         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 326         struct poly_req *preq = &rctx->u.poly;
 327         int err;
 328
 329         sg_init_table(preq->src, 1);
 330         sg_set_buf(preq->src, rctx->key, sizeof(rctx->key));
 331
 332         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 333                                    poly_setkey_done, req);
 334         ahash_request_set_tfm(&preq->req, ctx->poly);
 335         ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key));
 336
 337         err = crypto_ahash_update(&preq->req);
 338         if (err)
 339                 return err;
 340
 341         return poly_ad(req);
 342 }
 343
 344 static void poly_init_done(struct crypto_async_request *areq, int err)
 345 {
 346         async_done_continue(areq->data, err, poly_setkey);
 347 }
 348
 349 static int poly_init(struct aead_request *req)
 350 {
 351         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 352         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 353         struct poly_req *preq = &rctx->u.poly;
 354         int err;
 355
 356         ahash_request_set_callback(&preq->req, aead_request_flags(req),
 357                                    poly_init_done, req);
 358         ahash_request_set_tfm(&preq->req, ctx->poly);
 359
 360         err = crypto_ahash_init(&preq->req);
 361         if (err)
 362                 return err;
 363
 364         return poly_setkey(req);
 365 }
 366
 367 static void poly_genkey_done(struct crypto_async_request *areq, int err)
 368 {
 369         async_done_continue(areq->data, err, poly_init);
 370 }
 371
 372 static int poly_genkey(struct aead_request *req)
 373 {
 374         struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 375         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 376         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 377         struct chacha_req *creq = &rctx->u.chacha;
 378         int err;
 379
 380         rctx->assoclen = req->assoclen;
 381
 382         if (crypto_aead_ivsize(tfm) == 8) {
 383                 if (rctx->assoclen < 8)
 384                         return -EINVAL;
 385                 rctx->assoclen -= 8;
 386         }
 387
 388         sg_init_table(creq->src, 1);
 389         memset(rctx->key, 0, sizeof(rctx->key));
 390         sg_set_buf(creq->src, rctx->key, sizeof(rctx->key));
 391
 392         chacha_iv(creq->iv, req, 0);
 393
 394         skcipher_request_set_callback(&creq->req, aead_request_flags(req),
 395                                       poly_genkey_done, req);
 396         skcipher_request_set_tfm(&creq->req, ctx->chacha);
 397         skcipher_request_set_crypt(&creq->req, creq->src, creq->src,
 398                                    POLY1305_KEY_SIZE, creq->iv);
 399
 400         err = crypto_skcipher_decrypt(&creq->req);
 401         if (err)
 402                 return err;
 403
 404         return poly_init(req);
 405 }
 406
 407 static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
 408 {
 409         async_done_continue(areq->data, err, poly_genkey);
 410 }
 411
 412 static int chacha_encrypt(struct aead_request *req)
 413 {
 414         struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 415         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 416         struct chacha_req *creq = &rctx->u.chacha;
 417         struct scatterlist *src, *dst;
 418         int err;
 419
 420         if (req->cryptlen == 0)
 421                 goto skip;
 422
 423         chacha_iv(creq->iv, req, 1);
 424
 425         sg_init_table(rctx->src, 2);
 426         src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
 427         dst = src;
 428
 429         if (req->src != req->dst) {
 430                 sg_init_table(rctx->dst, 2);
 431                 dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
 432         }
 433
 434         skcipher_request_set_callback(&creq->req, aead_request_flags(req),
 435                                       chacha_encrypt_done, req);
 436         skcipher_request_set_tfm(&creq->req, ctx->chacha);
 437         skcipher_request_set_crypt(&creq->req, src, dst,
 438                                    req->cryptlen, creq->iv);
 439         err = crypto_skcipher_encrypt(&creq->req);
 440         if (err)
 441                 return err;
 442
 443 skip:
 444         return poly_genkey(req);
 445 }
 446
 447 static int chachapoly_encrypt(struct aead_request *req)
 448 {
 449         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 450
 451         rctx->cryptlen = req->cryptlen;
 452
 453         /* encrypt call chain:
 454          * - chacha_encrypt/done()
 455          * - poly_genkey/done()
 456          * - poly_init/done()
 457          * - poly_setkey/done()
 458          * - poly_ad/done()
 459          * - poly_adpad/done()
 460          * - poly_cipher/done()
 461          * - poly_cipherpad/done()
 462          * - poly_tail/done/continue()
 463          * - poly_copy_tag()
 464          */
 465         return chacha_encrypt(req);
 466 }
 467
 468 static int chachapoly_decrypt(struct aead_request *req)
 469 {
 470         struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 471
 472         rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
 473
 474         /* decrypt call chain:
 475          * - poly_genkey/done()
 476          * - poly_init/done()
 477          * - poly_setkey/done()
 478          * - poly_ad/done()
 479          * - poly_adpad/done()
 480          * - poly_cipher/done()
 481          * - poly_cipherpad/done()
 482          * - poly_tail/done/continue()
 483          * - chacha_decrypt/done()
 484          * - poly_verify_tag()
 485          */
 486         return poly_genkey(req);
 487 }
 488
 489 static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
 490                              unsigned int keylen)
 491 {
 492         struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
 493         int err;
 494
 495         if (keylen != ctx->saltlen + CHACHA_KEY_SIZE)
 496                 return -EINVAL;
 497
 498         keylen -= ctx->saltlen;
 499         memcpy(ctx->salt, key + keylen, ctx->saltlen);
 500
 501         crypto_skcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
 502         crypto_skcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
 503                                                CRYPTO_TFM_REQ_MASK);
 504
 505         err = crypto_skcipher_setkey(ctx->chacha, key, keylen);
 506         crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctx->chacha) &
 507                                     CRYPTO_TFM_RES_MASK);
 508         return err;
 509 }
 510
 511 static int chachapoly_setauthsize(struct crypto_aead *tfm,
 512                                   unsigned int authsize)
 513 {
 514         if (authsize != POLY1305_DIGEST_SIZE)
 515                 return -EINVAL;
 516
 517         return 0;
 518 }
 519
 520 static int chachapoly_init(struct crypto_aead *tfm)
 521 {
 522         struct aead_instance *inst = aead_alg_instance(tfm);
 523         struct chachapoly_instance_ctx *ictx = aead_instance_ctx(inst);
 524         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 525         struct crypto_skcipher *chacha;
 526         struct crypto_ahash *poly;
 527         unsigned long align;
 528
 529         poly = crypto_spawn_ahash(&ictx->poly);
 530         if (IS_ERR(poly))
 531                 return PTR_ERR(poly);
 532
 533         chacha = crypto_spawn_skcipher(&ictx->chacha);
 534         if (IS_ERR(chacha)) {
 535                 crypto_free_ahash(poly);
 536                 return PTR_ERR(chacha);
 537         }
 538
 539         ctx->chacha = chacha;
 540         ctx->poly = poly;
 541         ctx->saltlen = ictx->saltlen;
 542
 543         align = crypto_aead_alignmask(tfm);
 544         align &= ~(crypto_tfm_ctx_alignment() - 1);
 545         crypto_aead_set_reqsize(
 546                 tfm,
 547                 align + offsetof(struct chachapoly_req_ctx, u) +
 548                 max(offsetof(struct chacha_req, req) +
 549                     sizeof(struct skcipher_request) +
 550                     crypto_skcipher_reqsize(chacha),
 551                     offsetof(struct poly_req, req) +
 552                     sizeof(struct ahash_request) +
 553                     crypto_ahash_reqsize(poly)));
 554
 555         return 0;
 556 }
 557
 558 static void chachapoly_exit(struct crypto_aead *tfm)
 559 {
 560         struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 561
 562         crypto_free_ahash(ctx->poly);
 563         crypto_free_skcipher(ctx->chacha);
 564 }
 565
 566 static void chachapoly_free(struct aead_instance *inst)
 567 {
 568         struct chachapoly_instance_ctx *ctx = aead_instance_ctx(inst);
 569
 570         crypto_drop_skcipher(&ctx->chacha);
 571         crypto_drop_ahash(&ctx->poly);
 572         kfree(inst);
 573 }
 574
 575 static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
 576                              const char *name, unsigned int ivsize)
 577 {
 578         struct crypto_attr_type *algt;
 579         struct aead_instance *inst;
 580         struct skcipher_alg *chacha;
 581         struct crypto_alg *poly;
 582         struct hash_alg_common *poly_hash;
 583         struct chachapoly_instance_ctx *ctx;
 584         const char *chacha_name, *poly_name;
 585         int err;
 586
 587         if (ivsize > CHACHAPOLY_IV_SIZE)
 588                 return -EINVAL;
 589
 590         algt = crypto_get_attr_type(tb);
 591         if (IS_ERR(algt))
 592                 return PTR_ERR(algt);
 593
 594         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 595                 return -EINVAL;
 596
 597         chacha_name = crypto_attr_alg_name(tb[1]);
 598         if (IS_ERR(chacha_name))
 599                 return PTR_ERR(chacha_name);
 600         poly_name = crypto_attr_alg_name(tb[2]);
 601         if (IS_ERR(poly_name))
 602                 return PTR_ERR(poly_name);
 603
 604         poly = crypto_find_alg(poly_name, &crypto_ahash_type,
 605                                CRYPTO_ALG_TYPE_HASH,
 606                                CRYPTO_ALG_TYPE_AHASH_MASK |
 607                                crypto_requires_sync(algt->type,
 608                                                     algt->mask));
 609         if (IS_ERR(poly))
 610                 return PTR_ERR(poly);
 611         poly_hash = __crypto_hash_alg_common(poly);
 612
 613         err = -EINVAL;
 614         if (poly_hash->digestsize != POLY1305_DIGEST_SIZE)
 615                 goto out_put_poly;
 616
 617         err = -ENOMEM;
 618         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 619         if (!inst)
 620                 goto out_put_poly;
 621
 622         ctx = aead_instance_ctx(inst);
 623         ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
 624         err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
 625                                       aead_crypto_instance(inst));
 626         if (err)
 627                 goto err_free_inst;
 628
 629         crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
 630         err = crypto_grab_skcipher(&ctx->chacha, chacha_name, 0,
 631                                    crypto_requires_sync(algt->type,
 632                                                         algt->mask));
 633         if (err)
 634                 goto err_drop_poly;
 635
 636         chacha = crypto_spawn_skcipher_alg(&ctx->chacha);
 637
 638         err = -EINVAL;
 639         /* Need 16-byte IV size, including Initial Block Counter value */
 640         if (crypto_skcipher_alg_ivsize(chacha) != CHACHA_IV_SIZE)
 641                 goto out_drop_chacha;
 642         /* Not a stream cipher? */
 643         if (chacha->base.cra_blocksize != 1)
 644                 goto out_drop_chacha;
 645
 646         err = -ENAMETOOLONG;
 647         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 648                      "%s(%s,%s)", name, chacha->base.cra_name,
 649                      poly->cra_name) >= CRYPTO_MAX_ALG_NAME)
 650                 goto out_drop_chacha;
 651         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 652                      "%s(%s,%s)", name, chacha->base.cra_driver_name,
 653                      poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 654                 goto out_drop_chacha;
 655
 656         inst->alg.base.cra_flags = (chacha->base.cra_flags | poly->cra_flags) &
 657                                    CRYPTO_ALG_ASYNC;
 658         inst->alg.base.cra_priority = (chacha->base.cra_priority +
 659                                        poly->cra_priority) / 2;
 660         inst->alg.base.cra_blocksize = 1;
 661         inst->alg.base.cra_alignmask = chacha->base.cra_alignmask |
 662                                        poly->cra_alignmask;
 663         inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
 664                                      ctx->saltlen;
 665         inst->alg.ivsize = ivsize;
 666         inst->alg.chunksize = crypto_skcipher_alg_chunksize(chacha);
 667         inst->alg.maxauthsize = POLY1305_DIGEST_SIZE;
 668         inst->alg.init = chachapoly_init;
 669         inst->alg.exit = chachapoly_exit;
 670         inst->alg.encrypt = chachapoly_encrypt;
 671         inst->alg.decrypt = chachapoly_decrypt;
 672         inst->alg.setkey = chachapoly_setkey;
 673         inst->alg.setauthsize = chachapoly_setauthsize;
 674
 675         inst->free = chachapoly_free;
 676
 677         err = aead_register_instance(tmpl, inst);
 678         if (err)
 679                 goto out_drop_chacha;
 680
 681 out_put_poly:
 682         crypto_mod_put(poly);
 683         return err;
 684
 685 out_drop_chacha:
 686         crypto_drop_skcipher(&ctx->chacha);
 687 err_drop_poly:
 688         crypto_drop_ahash(&ctx->poly);
 689 err_free_inst:
 690         kfree(inst);
 691         goto out_put_poly;
 692 }
 693
 694 static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
 695 {
 696         return chachapoly_create(tmpl, tb, "rfc7539", 12);
 697 }
 698
 699 static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
 700 {
 701         return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
 702 }
 703
 704 static struct crypto_template rfc7539_tmpls[] = {
 705         {
 706                 .name = "rfc7539",
 707                 .create = rfc7539_create,
 708                 .module = THIS_MODULE,
 709         }, {
 710                 .name = "rfc7539esp",
 711                 .create = rfc7539esp_create,
 712                 .module = THIS_MODULE,
 713         },
 714 };
 715
 716 static int __init chacha20poly1305_module_init(void)
 717 {
 718         return crypto_register_templates(rfc7539_tmpls,
 719                                          ARRAY_SIZE(rfc7539_tmpls));
 720 }
 721
 722 static void __exit chacha20poly1305_module_exit(void)
 723 {
 724         crypto_unregister_templates(rfc7539_tmpls,
 725                                     ARRAY_SIZE(rfc7539_tmpls));
 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");