linux/crypto/chacha20poly1305.c
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   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
  27struct chachapoly_instance_ctx {
  28        struct crypto_skcipher_spawn chacha;
  29        struct crypto_ahash_spawn poly;
  30        unsigned int saltlen;
  31};
  32
  33struct 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
  41struct 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
  53struct chacha_req {
  54        u8 iv[CHACHA20_IV_SIZE];
  55        struct scatterlist src[1];
  56        struct skcipher_request req; /* must be last member */
  57};
  58
  59struct 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
  76static 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
  86static 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
  97static 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
 110static 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
 120static void chacha_decrypt_done(struct crypto_async_request *areq, int err)
 121{
 122        async_done_continue(areq->data, err, poly_verify_tag);
 123}
 124
 125static 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        sg_init_table(rctx->src, 2);
 139        src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
 140        dst = src;
 141
 142        if (req->src != req->dst) {
 143                sg_init_table(rctx->dst, 2);
 144                dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
 145        }
 146
 147        skcipher_request_set_callback(&creq->req, aead_request_flags(req),
 148                                      chacha_decrypt_done, req);
 149        skcipher_request_set_tfm(&creq->req, ctx->chacha);
 150        skcipher_request_set_crypt(&creq->req, src, dst,
 151                                   rctx->cryptlen, creq->iv);
 152        err = crypto_skcipher_decrypt(&creq->req);
 153        if (err)
 154                return err;
 155
 156skip:
 157        return poly_verify_tag(req);
 158}
 159
 160static int poly_tail_continue(struct aead_request *req)
 161{
 162        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 163
 164        if (rctx->cryptlen == req->cryptlen) /* encrypting */
 165                return poly_copy_tag(req);
 166
 167        return chacha_decrypt(req);
 168}
 169
 170static void poly_tail_done(struct crypto_async_request *areq, int err)
 171{
 172        async_done_continue(areq->data, err, poly_tail_continue);
 173}
 174
 175static int poly_tail(struct aead_request *req)
 176{
 177        struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 178        struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 179        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 180        struct poly_req *preq = &rctx->u.poly;
 181        __le64 len;
 182        int err;
 183
 184        sg_init_table(preq->src, 1);
 185        len = cpu_to_le64(rctx->assoclen);
 186        memcpy(&preq->tail.assoclen, &len, sizeof(len));
 187        len = cpu_to_le64(rctx->cryptlen);
 188        memcpy(&preq->tail.cryptlen, &len, sizeof(len));
 189        sg_set_buf(preq->src, &preq->tail, sizeof(preq->tail));
 190
 191        ahash_request_set_callback(&preq->req, aead_request_flags(req),
 192                                   poly_tail_done, req);
 193        ahash_request_set_tfm(&preq->req, ctx->poly);
 194        ahash_request_set_crypt(&preq->req, preq->src,
 195                                rctx->tag, sizeof(preq->tail));
 196
 197        err = crypto_ahash_finup(&preq->req);
 198        if (err)
 199                return err;
 200
 201        return poly_tail_continue(req);
 202}
 203
 204static void poly_cipherpad_done(struct crypto_async_request *areq, int err)
 205{
 206        async_done_continue(areq->data, err, poly_tail);
 207}
 208
 209static int poly_cipherpad(struct aead_request *req)
 210{
 211        struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 212        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 213        struct poly_req *preq = &rctx->u.poly;
 214        unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
 215        int err;
 216
 217        padlen = (bs - (rctx->cryptlen % bs)) % bs;
 218        memset(preq->pad, 0, sizeof(preq->pad));
 219        sg_init_table(preq->src, 1);
 220        sg_set_buf(preq->src, &preq->pad, padlen);
 221
 222        ahash_request_set_callback(&preq->req, aead_request_flags(req),
 223                                   poly_cipherpad_done, req);
 224        ahash_request_set_tfm(&preq->req, ctx->poly);
 225        ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
 226
 227        err = crypto_ahash_update(&preq->req);
 228        if (err)
 229                return err;
 230
 231        return poly_tail(req);
 232}
 233
 234static void poly_cipher_done(struct crypto_async_request *areq, int err)
 235{
 236        async_done_continue(areq->data, err, poly_cipherpad);
 237}
 238
 239static int poly_cipher(struct aead_request *req)
 240{
 241        struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 242        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 243        struct poly_req *preq = &rctx->u.poly;
 244        struct scatterlist *crypt = req->src;
 245        int err;
 246
 247        if (rctx->cryptlen == req->cryptlen) /* encrypting */
 248                crypt = req->dst;
 249
 250        sg_init_table(rctx->src, 2);
 251        crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);
 252
 253        ahash_request_set_callback(&preq->req, aead_request_flags(req),
 254                                   poly_cipher_done, req);
 255        ahash_request_set_tfm(&preq->req, ctx->poly);
 256        ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen);
 257
 258        err = crypto_ahash_update(&preq->req);
 259        if (err)
 260                return err;
 261
 262        return poly_cipherpad(req);
 263}
 264
 265static void poly_adpad_done(struct crypto_async_request *areq, int err)
 266{
 267        async_done_continue(areq->data, err, poly_cipher);
 268}
 269
 270static int poly_adpad(struct aead_request *req)
 271{
 272        struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 273        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 274        struct poly_req *preq = &rctx->u.poly;
 275        unsigned int padlen, bs = POLY1305_BLOCK_SIZE;
 276        int err;
 277
 278        padlen = (bs - (rctx->assoclen % bs)) % bs;
 279        memset(preq->pad, 0, sizeof(preq->pad));
 280        sg_init_table(preq->src, 1);
 281        sg_set_buf(preq->src, preq->pad, padlen);
 282
 283        ahash_request_set_callback(&preq->req, aead_request_flags(req),
 284                                   poly_adpad_done, req);
 285        ahash_request_set_tfm(&preq->req, ctx->poly);
 286        ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen);
 287
 288        err = crypto_ahash_update(&preq->req);
 289        if (err)
 290                return err;
 291
 292        return poly_cipher(req);
 293}
 294
 295static void poly_ad_done(struct crypto_async_request *areq, int err)
 296{
 297        async_done_continue(areq->data, err, poly_adpad);
 298}
 299
 300static int poly_ad(struct aead_request *req)
 301{
 302        struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 303        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 304        struct poly_req *preq = &rctx->u.poly;
 305        int err;
 306
 307        ahash_request_set_callback(&preq->req, aead_request_flags(req),
 308                                   poly_ad_done, req);
 309        ahash_request_set_tfm(&preq->req, ctx->poly);
 310        ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen);
 311
 312        err = crypto_ahash_update(&preq->req);
 313        if (err)
 314                return err;
 315
 316        return poly_adpad(req);
 317}
 318
 319static void poly_setkey_done(struct crypto_async_request *areq, int err)
 320{
 321        async_done_continue(areq->data, err, poly_ad);
 322}
 323
 324static int poly_setkey(struct aead_request *req)
 325{
 326        struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 327        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 328        struct poly_req *preq = &rctx->u.poly;
 329        int err;
 330
 331        sg_init_table(preq->src, 1);
 332        sg_set_buf(preq->src, rctx->key, sizeof(rctx->key));
 333
 334        ahash_request_set_callback(&preq->req, aead_request_flags(req),
 335                                   poly_setkey_done, req);
 336        ahash_request_set_tfm(&preq->req, ctx->poly);
 337        ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key));
 338
 339        err = crypto_ahash_update(&preq->req);
 340        if (err)
 341                return err;
 342
 343        return poly_ad(req);
 344}
 345
 346static void poly_init_done(struct crypto_async_request *areq, int err)
 347{
 348        async_done_continue(areq->data, err, poly_setkey);
 349}
 350
 351static int poly_init(struct aead_request *req)
 352{
 353        struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 354        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 355        struct poly_req *preq = &rctx->u.poly;
 356        int err;
 357
 358        ahash_request_set_callback(&preq->req, aead_request_flags(req),
 359                                   poly_init_done, req);
 360        ahash_request_set_tfm(&preq->req, ctx->poly);
 361
 362        err = crypto_ahash_init(&preq->req);
 363        if (err)
 364                return err;
 365
 366        return poly_setkey(req);
 367}
 368
 369static void poly_genkey_done(struct crypto_async_request *areq, int err)
 370{
 371        async_done_continue(areq->data, err, poly_init);
 372}
 373
 374static int poly_genkey(struct aead_request *req)
 375{
 376        struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 377        struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 378        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 379        struct chacha_req *creq = &rctx->u.chacha;
 380        int err;
 381
 382        rctx->assoclen = req->assoclen;
 383
 384        if (crypto_aead_ivsize(tfm) == 8) {
 385                if (rctx->assoclen < 8)
 386                        return -EINVAL;
 387                rctx->assoclen -= 8;
 388        }
 389
 390        sg_init_table(creq->src, 1);
 391        memset(rctx->key, 0, sizeof(rctx->key));
 392        sg_set_buf(creq->src, rctx->key, sizeof(rctx->key));
 393
 394        chacha_iv(creq->iv, req, 0);
 395
 396        skcipher_request_set_callback(&creq->req, aead_request_flags(req),
 397                                      poly_genkey_done, req);
 398        skcipher_request_set_tfm(&creq->req, ctx->chacha);
 399        skcipher_request_set_crypt(&creq->req, creq->src, creq->src,
 400                                   POLY1305_KEY_SIZE, creq->iv);
 401
 402        err = crypto_skcipher_decrypt(&creq->req);
 403        if (err)
 404                return err;
 405
 406        return poly_init(req);
 407}
 408
 409static void chacha_encrypt_done(struct crypto_async_request *areq, int err)
 410{
 411        async_done_continue(areq->data, err, poly_genkey);
 412}
 413
 414static int chacha_encrypt(struct aead_request *req)
 415{
 416        struct chachapoly_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 417        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 418        struct chacha_req *creq = &rctx->u.chacha;
 419        struct scatterlist *src, *dst;
 420        int err;
 421
 422        if (req->cryptlen == 0)
 423                goto skip;
 424
 425        chacha_iv(creq->iv, req, 1);
 426
 427        sg_init_table(rctx->src, 2);
 428        src = scatterwalk_ffwd(rctx->src, req->src, req->assoclen);
 429        dst = src;
 430
 431        if (req->src != req->dst) {
 432                sg_init_table(rctx->dst, 2);
 433                dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen);
 434        }
 435
 436        skcipher_request_set_callback(&creq->req, aead_request_flags(req),
 437                                      chacha_encrypt_done, req);
 438        skcipher_request_set_tfm(&creq->req, ctx->chacha);
 439        skcipher_request_set_crypt(&creq->req, src, dst,
 440                                   req->cryptlen, creq->iv);
 441        err = crypto_skcipher_encrypt(&creq->req);
 442        if (err)
 443                return err;
 444
 445skip:
 446        return poly_genkey(req);
 447}
 448
 449static int chachapoly_encrypt(struct aead_request *req)
 450{
 451        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 452
 453        rctx->cryptlen = req->cryptlen;
 454
 455        /* encrypt call chain:
 456         * - chacha_encrypt/done()
 457         * - poly_genkey/done()
 458         * - poly_init/done()
 459         * - poly_setkey/done()
 460         * - poly_ad/done()
 461         * - poly_adpad/done()
 462         * - poly_cipher/done()
 463         * - poly_cipherpad/done()
 464         * - poly_tail/done/continue()
 465         * - poly_copy_tag()
 466         */
 467        return chacha_encrypt(req);
 468}
 469
 470static int chachapoly_decrypt(struct aead_request *req)
 471{
 472        struct chachapoly_req_ctx *rctx = aead_request_ctx(req);
 473
 474        rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE;
 475
 476        /* decrypt call chain:
 477         * - poly_genkey/done()
 478         * - poly_init/done()
 479         * - poly_setkey/done()
 480         * - poly_ad/done()
 481         * - poly_adpad/done()
 482         * - poly_cipher/done()
 483         * - poly_cipherpad/done()
 484         * - poly_tail/done/continue()
 485         * - chacha_decrypt/done()
 486         * - poly_verify_tag()
 487         */
 488        return poly_genkey(req);
 489}
 490
 491static int chachapoly_setkey(struct crypto_aead *aead, const u8 *key,
 492                             unsigned int keylen)
 493{
 494        struct chachapoly_ctx *ctx = crypto_aead_ctx(aead);
 495        int err;
 496
 497        if (keylen != ctx->saltlen + CHACHA20_KEY_SIZE)
 498                return -EINVAL;
 499
 500        keylen -= ctx->saltlen;
 501        memcpy(ctx->salt, key + keylen, ctx->saltlen);
 502
 503        crypto_skcipher_clear_flags(ctx->chacha, CRYPTO_TFM_REQ_MASK);
 504        crypto_skcipher_set_flags(ctx->chacha, crypto_aead_get_flags(aead) &
 505                                               CRYPTO_TFM_REQ_MASK);
 506
 507        err = crypto_skcipher_setkey(ctx->chacha, key, keylen);
 508        crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctx->chacha) &
 509                                    CRYPTO_TFM_RES_MASK);
 510        return err;
 511}
 512
 513static int chachapoly_setauthsize(struct crypto_aead *tfm,
 514                                  unsigned int authsize)
 515{
 516        if (authsize != POLY1305_DIGEST_SIZE)
 517                return -EINVAL;
 518
 519        return 0;
 520}
 521
 522static int chachapoly_init(struct crypto_aead *tfm)
 523{
 524        struct aead_instance *inst = aead_alg_instance(tfm);
 525        struct chachapoly_instance_ctx *ictx = aead_instance_ctx(inst);
 526        struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 527        struct crypto_skcipher *chacha;
 528        struct crypto_ahash *poly;
 529        unsigned long align;
 530
 531        poly = crypto_spawn_ahash(&ictx->poly);
 532        if (IS_ERR(poly))
 533                return PTR_ERR(poly);
 534
 535        chacha = crypto_spawn_skcipher(&ictx->chacha);
 536        if (IS_ERR(chacha)) {
 537                crypto_free_ahash(poly);
 538                return PTR_ERR(chacha);
 539        }
 540
 541        ctx->chacha = chacha;
 542        ctx->poly = poly;
 543        ctx->saltlen = ictx->saltlen;
 544
 545        align = crypto_aead_alignmask(tfm);
 546        align &= ~(crypto_tfm_ctx_alignment() - 1);
 547        crypto_aead_set_reqsize(
 548                tfm,
 549                align + offsetof(struct chachapoly_req_ctx, u) +
 550                max(offsetof(struct chacha_req, req) +
 551                    sizeof(struct skcipher_request) +
 552                    crypto_skcipher_reqsize(chacha),
 553                    offsetof(struct poly_req, req) +
 554                    sizeof(struct ahash_request) +
 555                    crypto_ahash_reqsize(poly)));
 556
 557        return 0;
 558}
 559
 560static void chachapoly_exit(struct crypto_aead *tfm)
 561{
 562        struct chachapoly_ctx *ctx = crypto_aead_ctx(tfm);
 563
 564        crypto_free_ahash(ctx->poly);
 565        crypto_free_skcipher(ctx->chacha);
 566}
 567
 568static void chachapoly_free(struct aead_instance *inst)
 569{
 570        struct chachapoly_instance_ctx *ctx = aead_instance_ctx(inst);
 571
 572        crypto_drop_skcipher(&ctx->chacha);
 573        crypto_drop_ahash(&ctx->poly);
 574        kfree(inst);
 575}
 576
 577static int chachapoly_create(struct crypto_template *tmpl, struct rtattr **tb,
 578                             const char *name, unsigned int ivsize)
 579{
 580        struct crypto_attr_type *algt;
 581        struct aead_instance *inst;
 582        struct skcipher_alg *chacha;
 583        struct crypto_alg *poly;
 584        struct hash_alg_common *poly_hash;
 585        struct chachapoly_instance_ctx *ctx;
 586        const char *chacha_name, *poly_name;
 587        int err;
 588
 589        if (ivsize > CHACHAPOLY_IV_SIZE)
 590                return -EINVAL;
 591
 592        algt = crypto_get_attr_type(tb);
 593        if (IS_ERR(algt))
 594                return PTR_ERR(algt);
 595
 596        if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 597                return -EINVAL;
 598
 599        chacha_name = crypto_attr_alg_name(tb[1]);
 600        if (IS_ERR(chacha_name))
 601                return PTR_ERR(chacha_name);
 602        poly_name = crypto_attr_alg_name(tb[2]);
 603        if (IS_ERR(poly_name))
 604                return PTR_ERR(poly_name);
 605
 606        poly = crypto_find_alg(poly_name, &crypto_ahash_type,
 607                               CRYPTO_ALG_TYPE_HASH,
 608                               CRYPTO_ALG_TYPE_AHASH_MASK |
 609                               crypto_requires_sync(algt->type,
 610                                                    algt->mask));
 611        if (IS_ERR(poly))
 612                return PTR_ERR(poly);
 613        poly_hash = __crypto_hash_alg_common(poly);
 614
 615        err = -EINVAL;
 616        if (poly_hash->digestsize != POLY1305_DIGEST_SIZE)
 617                goto out_put_poly;
 618
 619        err = -ENOMEM;
 620        inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 621        if (!inst)
 622                goto out_put_poly;
 623
 624        ctx = aead_instance_ctx(inst);
 625        ctx->saltlen = CHACHAPOLY_IV_SIZE - ivsize;
 626        err = crypto_init_ahash_spawn(&ctx->poly, poly_hash,
 627                                      aead_crypto_instance(inst));
 628        if (err)
 629                goto err_free_inst;
 630
 631        crypto_set_skcipher_spawn(&ctx->chacha, aead_crypto_instance(inst));
 632        err = crypto_grab_skcipher(&ctx->chacha, chacha_name, 0,
 633                                   crypto_requires_sync(algt->type,
 634                                                        algt->mask));
 635        if (err)
 636                goto err_drop_poly;
 637
 638        chacha = crypto_spawn_skcipher_alg(&ctx->chacha);
 639
 640        err = -EINVAL;
 641        /* Need 16-byte IV size, including Initial Block Counter value */
 642        if (crypto_skcipher_alg_ivsize(chacha) != CHACHA20_IV_SIZE)
 643                goto out_drop_chacha;
 644        /* Not a stream cipher? */
 645        if (chacha->base.cra_blocksize != 1)
 646                goto out_drop_chacha;
 647
 648        err = -ENAMETOOLONG;
 649        if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 650                     "%s(%s,%s)", name, chacha_name,
 651                     poly_name) >= CRYPTO_MAX_ALG_NAME)
 652                goto out_drop_chacha;
 653        if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 654                     "%s(%s,%s)", name, chacha->base.cra_driver_name,
 655                     poly->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 656                goto out_drop_chacha;
 657
 658        inst->alg.base.cra_flags = (chacha->base.cra_flags | poly->cra_flags) &
 659                                   CRYPTO_ALG_ASYNC;
 660        inst->alg.base.cra_priority = (chacha->base.cra_priority +
 661                                       poly->cra_priority) / 2;
 662        inst->alg.base.cra_blocksize = 1;
 663        inst->alg.base.cra_alignmask = chacha->base.cra_alignmask |
 664                                       poly->cra_alignmask;
 665        inst->alg.base.cra_ctxsize = sizeof(struct chachapoly_ctx) +
 666                                     ctx->saltlen;
 667        inst->alg.ivsize = ivsize;
 668        inst->alg.chunksize = crypto_skcipher_alg_chunksize(chacha);
 669        inst->alg.maxauthsize = POLY1305_DIGEST_SIZE;
 670        inst->alg.init = chachapoly_init;
 671        inst->alg.exit = chachapoly_exit;
 672        inst->alg.encrypt = chachapoly_encrypt;
 673        inst->alg.decrypt = chachapoly_decrypt;
 674        inst->alg.setkey = chachapoly_setkey;
 675        inst->alg.setauthsize = chachapoly_setauthsize;
 676
 677        inst->free = chachapoly_free;
 678
 679        err = aead_register_instance(tmpl, inst);
 680        if (err)
 681                goto out_drop_chacha;
 682
 683out_put_poly:
 684        crypto_mod_put(poly);
 685        return err;
 686
 687out_drop_chacha:
 688        crypto_drop_skcipher(&ctx->chacha);
 689err_drop_poly:
 690        crypto_drop_ahash(&ctx->poly);
 691err_free_inst:
 692        kfree(inst);
 693        goto out_put_poly;
 694}
 695
 696static int rfc7539_create(struct crypto_template *tmpl, struct rtattr **tb)
 697{
 698        return chachapoly_create(tmpl, tb, "rfc7539", 12);
 699}
 700
 701static int rfc7539esp_create(struct crypto_template *tmpl, struct rtattr **tb)
 702{
 703        return chachapoly_create(tmpl, tb, "rfc7539esp", 8);
 704}
 705
 706static struct crypto_template rfc7539_tmpl = {
 707        .name = "rfc7539",
 708        .create = rfc7539_create,
 709        .module = THIS_MODULE,
 710};
 711
 712static struct crypto_template rfc7539esp_tmpl = {
 713        .name = "rfc7539esp",
 714        .create = rfc7539esp_create,
 715        .module = THIS_MODULE,
 716};
 717
 718static int __init chacha20poly1305_module_init(void)
 719{
 720        int err;
 721
 722        err = crypto_register_template(&rfc7539_tmpl);
 723        if (err)
 724                return err;
 725
 726        err = crypto_register_template(&rfc7539esp_tmpl);
 727        if (err)
 728                crypto_unregister_template(&rfc7539_tmpl);
 729
 730        return err;
 731}
 732
 733static void __exit chacha20poly1305_module_exit(void)
 734{
 735        crypto_unregister_template(&rfc7539esp_tmpl);
 736        crypto_unregister_template(&rfc7539_tmpl);
 737}
 738
 739module_init(chacha20poly1305_module_init);
 740module_exit(chacha20poly1305_module_exit);
 741
 742MODULE_LICENSE("GPL");
 743MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
 744MODULE_DESCRIPTION("ChaCha20-Poly1305 AEAD");
 745MODULE_ALIAS_CRYPTO("rfc7539");
 746MODULE_ALIAS_CRYPTO("rfc7539esp");
 747