linux/crypto/ccm.c
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   1/*
   2 * CCM: Counter with CBC-MAC
   3 *
   4 * (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
   5 *
   6 * This program is free software; you can redistribute it and/or modify it
   7 * under the terms of the GNU General Public License as published by the Free
   8 * Software Foundation; either version 2 of the License, or (at your option)
   9 * any later version.
  10 *
  11 */
  12
  13#include <crypto/internal/aead.h>
  14#include <crypto/internal/skcipher.h>
  15#include <crypto/scatterwalk.h>
  16#include <linux/err.h>
  17#include <linux/init.h>
  18#include <linux/kernel.h>
  19#include <linux/module.h>
  20#include <linux/slab.h>
  21
  22#include "internal.h"
  23
  24struct ccm_instance_ctx {
  25        struct crypto_skcipher_spawn ctr;
  26        struct crypto_spawn cipher;
  27};
  28
  29struct crypto_ccm_ctx {
  30        struct crypto_cipher *cipher;
  31        struct crypto_ablkcipher *ctr;
  32};
  33
  34struct crypto_rfc4309_ctx {
  35        struct crypto_aead *child;
  36        u8 nonce[3];
  37};
  38
  39struct crypto_ccm_req_priv_ctx {
  40        u8 odata[16];
  41        u8 idata[16];
  42        u8 auth_tag[16];
  43        u32 ilen;
  44        u32 flags;
  45        struct scatterlist src[2];
  46        struct scatterlist dst[2];
  47        struct ablkcipher_request abreq;
  48};
  49
  50static inline struct crypto_ccm_req_priv_ctx *crypto_ccm_reqctx(
  51        struct aead_request *req)
  52{
  53        unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));
  54
  55        return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
  56}
  57
  58static int set_msg_len(u8 *block, unsigned int msglen, int csize)
  59{
  60        __be32 data;
  61
  62        memset(block, 0, csize);
  63        block += csize;
  64
  65        if (csize >= 4)
  66                csize = 4;
  67        else if (msglen > (1 << (8 * csize)))
  68                return -EOVERFLOW;
  69
  70        data = cpu_to_be32(msglen);
  71        memcpy(block - csize, (u8 *)&data + 4 - csize, csize);
  72
  73        return 0;
  74}
  75
  76static int crypto_ccm_setkey(struct crypto_aead *aead, const u8 *key,
  77                             unsigned int keylen)
  78{
  79        struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
  80        struct crypto_ablkcipher *ctr = ctx->ctr;
  81        struct crypto_cipher *tfm = ctx->cipher;
  82        int err = 0;
  83
  84        crypto_ablkcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
  85        crypto_ablkcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
  86                                    CRYPTO_TFM_REQ_MASK);
  87        err = crypto_ablkcipher_setkey(ctr, key, keylen);
  88        crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctr) &
  89                              CRYPTO_TFM_RES_MASK);
  90        if (err)
  91                goto out;
  92
  93        crypto_cipher_clear_flags(tfm, CRYPTO_TFM_REQ_MASK);
  94        crypto_cipher_set_flags(tfm, crypto_aead_get_flags(aead) &
  95                                    CRYPTO_TFM_REQ_MASK);
  96        err = crypto_cipher_setkey(tfm, key, keylen);
  97        crypto_aead_set_flags(aead, crypto_cipher_get_flags(tfm) &
  98                              CRYPTO_TFM_RES_MASK);
  99
 100out:
 101        return err;
 102}
 103
 104static int crypto_ccm_setauthsize(struct crypto_aead *tfm,
 105                                  unsigned int authsize)
 106{
 107        switch (authsize) {
 108        case 4:
 109        case 6:
 110        case 8:
 111        case 10:
 112        case 12:
 113        case 14:
 114        case 16:
 115                break;
 116        default:
 117                return -EINVAL;
 118        }
 119
 120        return 0;
 121}
 122
 123static int format_input(u8 *info, struct aead_request *req,
 124                        unsigned int cryptlen)
 125{
 126        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 127        unsigned int lp = req->iv[0];
 128        unsigned int l = lp + 1;
 129        unsigned int m;
 130
 131        m = crypto_aead_authsize(aead);
 132
 133        memcpy(info, req->iv, 16);
 134
 135        /* format control info per RFC 3610 and
 136         * NIST Special Publication 800-38C
 137         */
 138        *info |= (8 * ((m - 2) / 2));
 139        if (req->assoclen)
 140                *info |= 64;
 141
 142        return set_msg_len(info + 16 - l, cryptlen, l);
 143}
 144
 145static int format_adata(u8 *adata, unsigned int a)
 146{
 147        int len = 0;
 148
 149        /* add control info for associated data
 150         * RFC 3610 and NIST Special Publication 800-38C
 151         */
 152        if (a < 65280) {
 153                *(__be16 *)adata = cpu_to_be16(a);
 154                len = 2;
 155        } else  {
 156                *(__be16 *)adata = cpu_to_be16(0xfffe);
 157                *(__be32 *)&adata[2] = cpu_to_be32(a);
 158                len = 6;
 159        }
 160
 161        return len;
 162}
 163
 164static void compute_mac(struct crypto_cipher *tfm, u8 *data, int n,
 165                       struct crypto_ccm_req_priv_ctx *pctx)
 166{
 167        unsigned int bs = 16;
 168        u8 *odata = pctx->odata;
 169        u8 *idata = pctx->idata;
 170        int datalen, getlen;
 171
 172        datalen = n;
 173
 174        /* first time in here, block may be partially filled. */
 175        getlen = bs - pctx->ilen;
 176        if (datalen >= getlen) {
 177                memcpy(idata + pctx->ilen, data, getlen);
 178                crypto_xor(odata, idata, bs);
 179                crypto_cipher_encrypt_one(tfm, odata, odata);
 180                datalen -= getlen;
 181                data += getlen;
 182                pctx->ilen = 0;
 183        }
 184
 185        /* now encrypt rest of data */
 186        while (datalen >= bs) {
 187                crypto_xor(odata, data, bs);
 188                crypto_cipher_encrypt_one(tfm, odata, odata);
 189
 190                datalen -= bs;
 191                data += bs;
 192        }
 193
 194        /* check and see if there's leftover data that wasn't
 195         * enough to fill a block.
 196         */
 197        if (datalen) {
 198                memcpy(idata + pctx->ilen, data, datalen);
 199                pctx->ilen += datalen;
 200        }
 201}
 202
 203static void get_data_to_compute(struct crypto_cipher *tfm,
 204                               struct crypto_ccm_req_priv_ctx *pctx,
 205                               struct scatterlist *sg, unsigned int len)
 206{
 207        struct scatter_walk walk;
 208        u8 *data_src;
 209        int n;
 210
 211        scatterwalk_start(&walk, sg);
 212
 213        while (len) {
 214                n = scatterwalk_clamp(&walk, len);
 215                if (!n) {
 216                        scatterwalk_start(&walk, sg_next(walk.sg));
 217                        n = scatterwalk_clamp(&walk, len);
 218                }
 219                data_src = scatterwalk_map(&walk);
 220
 221                compute_mac(tfm, data_src, n, pctx);
 222                len -= n;
 223
 224                scatterwalk_unmap(data_src);
 225                scatterwalk_advance(&walk, n);
 226                scatterwalk_done(&walk, 0, len);
 227                if (len)
 228                        crypto_yield(pctx->flags);
 229        }
 230
 231        /* any leftover needs padding and then encrypted */
 232        if (pctx->ilen) {
 233                int padlen;
 234                u8 *odata = pctx->odata;
 235                u8 *idata = pctx->idata;
 236
 237                padlen = 16 - pctx->ilen;
 238                memset(idata + pctx->ilen, 0, padlen);
 239                crypto_xor(odata, idata, 16);
 240                crypto_cipher_encrypt_one(tfm, odata, odata);
 241                pctx->ilen = 0;
 242        }
 243}
 244
 245static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain,
 246                           unsigned int cryptlen)
 247{
 248        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 249        struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
 250        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 251        struct crypto_cipher *cipher = ctx->cipher;
 252        unsigned int assoclen = req->assoclen;
 253        u8 *odata = pctx->odata;
 254        u8 *idata = pctx->idata;
 255        int err;
 256
 257        /* format control data for input */
 258        err = format_input(odata, req, cryptlen);
 259        if (err)
 260                goto out;
 261
 262        /* encrypt first block to use as start in computing mac  */
 263        crypto_cipher_encrypt_one(cipher, odata, odata);
 264
 265        /* format associated data and compute into mac */
 266        if (assoclen) {
 267                pctx->ilen = format_adata(idata, assoclen);
 268                get_data_to_compute(cipher, pctx, req->assoc, req->assoclen);
 269        } else {
 270                pctx->ilen = 0;
 271        }
 272
 273        /* compute plaintext into mac */
 274        get_data_to_compute(cipher, pctx, plain, cryptlen);
 275
 276out:
 277        return err;
 278}
 279
 280static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err)
 281{
 282        struct aead_request *req = areq->data;
 283        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 284        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 285        u8 *odata = pctx->odata;
 286
 287        if (!err)
 288                scatterwalk_map_and_copy(odata, req->dst, req->cryptlen,
 289                                         crypto_aead_authsize(aead), 1);
 290        aead_request_complete(req, err);
 291}
 292
 293static inline int crypto_ccm_check_iv(const u8 *iv)
 294{
 295        /* 2 <= L <= 8, so 1 <= L' <= 7. */
 296        if (1 > iv[0] || iv[0] > 7)
 297                return -EINVAL;
 298
 299        return 0;
 300}
 301
 302static int crypto_ccm_encrypt(struct aead_request *req)
 303{
 304        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 305        struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
 306        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 307        struct ablkcipher_request *abreq = &pctx->abreq;
 308        struct scatterlist *dst;
 309        unsigned int cryptlen = req->cryptlen;
 310        u8 *odata = pctx->odata;
 311        u8 *iv = req->iv;
 312        int err;
 313
 314        err = crypto_ccm_check_iv(iv);
 315        if (err)
 316                return err;
 317
 318        pctx->flags = aead_request_flags(req);
 319
 320        err = crypto_ccm_auth(req, req->src, cryptlen);
 321        if (err)
 322                return err;
 323
 324         /* Note: rfc 3610 and NIST 800-38C require counter of
 325         * zero to encrypt auth tag.
 326         */
 327        memset(iv + 15 - iv[0], 0, iv[0] + 1);
 328
 329        sg_init_table(pctx->src, 2);
 330        sg_set_buf(pctx->src, odata, 16);
 331        scatterwalk_sg_chain(pctx->src, 2, req->src);
 332
 333        dst = pctx->src;
 334        if (req->src != req->dst) {
 335                sg_init_table(pctx->dst, 2);
 336                sg_set_buf(pctx->dst, odata, 16);
 337                scatterwalk_sg_chain(pctx->dst, 2, req->dst);
 338                dst = pctx->dst;
 339        }
 340
 341        ablkcipher_request_set_tfm(abreq, ctx->ctr);
 342        ablkcipher_request_set_callback(abreq, pctx->flags,
 343                                        crypto_ccm_encrypt_done, req);
 344        ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
 345        err = crypto_ablkcipher_encrypt(abreq);
 346        if (err)
 347                return err;
 348
 349        /* copy authtag to end of dst */
 350        scatterwalk_map_and_copy(odata, req->dst, cryptlen,
 351                                 crypto_aead_authsize(aead), 1);
 352        return err;
 353}
 354
 355static void crypto_ccm_decrypt_done(struct crypto_async_request *areq,
 356                                   int err)
 357{
 358        struct aead_request *req = areq->data;
 359        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 360        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 361        unsigned int authsize = crypto_aead_authsize(aead);
 362        unsigned int cryptlen = req->cryptlen - authsize;
 363
 364        if (!err) {
 365                err = crypto_ccm_auth(req, req->dst, cryptlen);
 366                if (!err && memcmp(pctx->auth_tag, pctx->odata, authsize))
 367                        err = -EBADMSG;
 368        }
 369        aead_request_complete(req, err);
 370}
 371
 372static int crypto_ccm_decrypt(struct aead_request *req)
 373{
 374        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 375        struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
 376        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 377        struct ablkcipher_request *abreq = &pctx->abreq;
 378        struct scatterlist *dst;
 379        unsigned int authsize = crypto_aead_authsize(aead);
 380        unsigned int cryptlen = req->cryptlen;
 381        u8 *authtag = pctx->auth_tag;
 382        u8 *odata = pctx->odata;
 383        u8 *iv = req->iv;
 384        int err;
 385
 386        if (cryptlen < authsize)
 387                return -EINVAL;
 388        cryptlen -= authsize;
 389
 390        err = crypto_ccm_check_iv(iv);
 391        if (err)
 392                return err;
 393
 394        pctx->flags = aead_request_flags(req);
 395
 396        scatterwalk_map_and_copy(authtag, req->src, cryptlen, authsize, 0);
 397
 398        memset(iv + 15 - iv[0], 0, iv[0] + 1);
 399
 400        sg_init_table(pctx->src, 2);
 401        sg_set_buf(pctx->src, authtag, 16);
 402        scatterwalk_sg_chain(pctx->src, 2, req->src);
 403
 404        dst = pctx->src;
 405        if (req->src != req->dst) {
 406                sg_init_table(pctx->dst, 2);
 407                sg_set_buf(pctx->dst, authtag, 16);
 408                scatterwalk_sg_chain(pctx->dst, 2, req->dst);
 409                dst = pctx->dst;
 410        }
 411
 412        ablkcipher_request_set_tfm(abreq, ctx->ctr);
 413        ablkcipher_request_set_callback(abreq, pctx->flags,
 414                                        crypto_ccm_decrypt_done, req);
 415        ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
 416        err = crypto_ablkcipher_decrypt(abreq);
 417        if (err)
 418                return err;
 419
 420        err = crypto_ccm_auth(req, req->dst, cryptlen);
 421        if (err)
 422                return err;
 423
 424        /* verify */
 425        if (memcmp(authtag, odata, authsize))
 426                return -EBADMSG;
 427
 428        return err;
 429}
 430
 431static int crypto_ccm_init_tfm(struct crypto_tfm *tfm)
 432{
 433        struct crypto_instance *inst = (void *)tfm->__crt_alg;
 434        struct ccm_instance_ctx *ictx = crypto_instance_ctx(inst);
 435        struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
 436        struct crypto_cipher *cipher;
 437        struct crypto_ablkcipher *ctr;
 438        unsigned long align;
 439        int err;
 440
 441        cipher = crypto_spawn_cipher(&ictx->cipher);
 442        if (IS_ERR(cipher))
 443                return PTR_ERR(cipher);
 444
 445        ctr = crypto_spawn_skcipher(&ictx->ctr);
 446        err = PTR_ERR(ctr);
 447        if (IS_ERR(ctr))
 448                goto err_free_cipher;
 449
 450        ctx->cipher = cipher;
 451        ctx->ctr = ctr;
 452
 453        align = crypto_tfm_alg_alignmask(tfm);
 454        align &= ~(crypto_tfm_ctx_alignment() - 1);
 455        tfm->crt_aead.reqsize = align +
 456                                sizeof(struct crypto_ccm_req_priv_ctx) +
 457                                crypto_ablkcipher_reqsize(ctr);
 458
 459        return 0;
 460
 461err_free_cipher:
 462        crypto_free_cipher(cipher);
 463        return err;
 464}
 465
 466static void crypto_ccm_exit_tfm(struct crypto_tfm *tfm)
 467{
 468        struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
 469
 470        crypto_free_cipher(ctx->cipher);
 471        crypto_free_ablkcipher(ctx->ctr);
 472}
 473
 474static struct crypto_instance *crypto_ccm_alloc_common(struct rtattr **tb,
 475                                                       const char *full_name,
 476                                                       const char *ctr_name,
 477                                                       const char *cipher_name)
 478{
 479        struct crypto_attr_type *algt;
 480        struct crypto_instance *inst;
 481        struct crypto_alg *ctr;
 482        struct crypto_alg *cipher;
 483        struct ccm_instance_ctx *ictx;
 484        int err;
 485
 486        algt = crypto_get_attr_type(tb);
 487        if (IS_ERR(algt))
 488                return ERR_CAST(algt);
 489
 490        if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 491                return ERR_PTR(-EINVAL);
 492
 493        cipher = crypto_alg_mod_lookup(cipher_name,  CRYPTO_ALG_TYPE_CIPHER,
 494                                       CRYPTO_ALG_TYPE_MASK);
 495        if (IS_ERR(cipher))
 496                return ERR_CAST(cipher);
 497
 498        err = -EINVAL;
 499        if (cipher->cra_blocksize != 16)
 500                goto out_put_cipher;
 501
 502        inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
 503        err = -ENOMEM;
 504        if (!inst)
 505                goto out_put_cipher;
 506
 507        ictx = crypto_instance_ctx(inst);
 508
 509        err = crypto_init_spawn(&ictx->cipher, cipher, inst,
 510                                CRYPTO_ALG_TYPE_MASK);
 511        if (err)
 512                goto err_free_inst;
 513
 514        crypto_set_skcipher_spawn(&ictx->ctr, inst);
 515        err = crypto_grab_skcipher(&ictx->ctr, ctr_name, 0,
 516                                   crypto_requires_sync(algt->type,
 517                                                        algt->mask));
 518        if (err)
 519                goto err_drop_cipher;
 520
 521        ctr = crypto_skcipher_spawn_alg(&ictx->ctr);
 522
 523        /* Not a stream cipher? */
 524        err = -EINVAL;
 525        if (ctr->cra_blocksize != 1)
 526                goto err_drop_ctr;
 527
 528        /* We want the real thing! */
 529        if (ctr->cra_ablkcipher.ivsize != 16)
 530                goto err_drop_ctr;
 531
 532        err = -ENAMETOOLONG;
 533        if (snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 534                     "ccm_base(%s,%s)", ctr->cra_driver_name,
 535                     cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 536                goto err_drop_ctr;
 537
 538        memcpy(inst->alg.cra_name, full_name, CRYPTO_MAX_ALG_NAME);
 539
 540        inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
 541        inst->alg.cra_flags |= ctr->cra_flags & CRYPTO_ALG_ASYNC;
 542        inst->alg.cra_priority = cipher->cra_priority + ctr->cra_priority;
 543        inst->alg.cra_blocksize = 1;
 544        inst->alg.cra_alignmask = cipher->cra_alignmask | ctr->cra_alignmask |
 545                                  (__alignof__(u32) - 1);
 546        inst->alg.cra_type = &crypto_aead_type;
 547        inst->alg.cra_aead.ivsize = 16;
 548        inst->alg.cra_aead.maxauthsize = 16;
 549        inst->alg.cra_ctxsize = sizeof(struct crypto_ccm_ctx);
 550        inst->alg.cra_init = crypto_ccm_init_tfm;
 551        inst->alg.cra_exit = crypto_ccm_exit_tfm;
 552        inst->alg.cra_aead.setkey = crypto_ccm_setkey;
 553        inst->alg.cra_aead.setauthsize = crypto_ccm_setauthsize;
 554        inst->alg.cra_aead.encrypt = crypto_ccm_encrypt;
 555        inst->alg.cra_aead.decrypt = crypto_ccm_decrypt;
 556
 557out:
 558        crypto_mod_put(cipher);
 559        return inst;
 560
 561err_drop_ctr:
 562        crypto_drop_skcipher(&ictx->ctr);
 563err_drop_cipher:
 564        crypto_drop_spawn(&ictx->cipher);
 565err_free_inst:
 566        kfree(inst);
 567out_put_cipher:
 568        inst = ERR_PTR(err);
 569        goto out;
 570}
 571
 572static struct crypto_instance *crypto_ccm_alloc(struct rtattr **tb)
 573{
 574        const char *cipher_name;
 575        char ctr_name[CRYPTO_MAX_ALG_NAME];
 576        char full_name[CRYPTO_MAX_ALG_NAME];
 577
 578        cipher_name = crypto_attr_alg_name(tb[1]);
 579        if (IS_ERR(cipher_name))
 580                return ERR_CAST(cipher_name);
 581
 582        if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
 583                     cipher_name) >= CRYPTO_MAX_ALG_NAME)
 584                return ERR_PTR(-ENAMETOOLONG);
 585
 586        if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >=
 587            CRYPTO_MAX_ALG_NAME)
 588                return ERR_PTR(-ENAMETOOLONG);
 589
 590        return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
 591}
 592
 593static void crypto_ccm_free(struct crypto_instance *inst)
 594{
 595        struct ccm_instance_ctx *ctx = crypto_instance_ctx(inst);
 596
 597        crypto_drop_spawn(&ctx->cipher);
 598        crypto_drop_skcipher(&ctx->ctr);
 599        kfree(inst);
 600}
 601
 602static struct crypto_template crypto_ccm_tmpl = {
 603        .name = "ccm",
 604        .alloc = crypto_ccm_alloc,
 605        .free = crypto_ccm_free,
 606        .module = THIS_MODULE,
 607};
 608
 609static struct crypto_instance *crypto_ccm_base_alloc(struct rtattr **tb)
 610{
 611        const char *ctr_name;
 612        const char *cipher_name;
 613        char full_name[CRYPTO_MAX_ALG_NAME];
 614
 615        ctr_name = crypto_attr_alg_name(tb[1]);
 616        if (IS_ERR(ctr_name))
 617                return ERR_CAST(ctr_name);
 618
 619        cipher_name = crypto_attr_alg_name(tb[2]);
 620        if (IS_ERR(cipher_name))
 621                return ERR_CAST(cipher_name);
 622
 623        if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)",
 624                     ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME)
 625                return ERR_PTR(-ENAMETOOLONG);
 626
 627        return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
 628}
 629
 630static struct crypto_template crypto_ccm_base_tmpl = {
 631        .name = "ccm_base",
 632        .alloc = crypto_ccm_base_alloc,
 633        .free = crypto_ccm_free,
 634        .module = THIS_MODULE,
 635};
 636
 637static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
 638                                 unsigned int keylen)
 639{
 640        struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
 641        struct crypto_aead *child = ctx->child;
 642        int err;
 643
 644        if (keylen < 3)
 645                return -EINVAL;
 646
 647        keylen -= 3;
 648        memcpy(ctx->nonce, key + keylen, 3);
 649
 650        crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 651        crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
 652                                     CRYPTO_TFM_REQ_MASK);
 653        err = crypto_aead_setkey(child, key, keylen);
 654        crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
 655                                      CRYPTO_TFM_RES_MASK);
 656
 657        return err;
 658}
 659
 660static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
 661                                      unsigned int authsize)
 662{
 663        struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
 664
 665        switch (authsize) {
 666        case 8:
 667        case 12:
 668        case 16:
 669                break;
 670        default:
 671                return -EINVAL;
 672        }
 673
 674        return crypto_aead_setauthsize(ctx->child, authsize);
 675}
 676
 677static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
 678{
 679        struct aead_request *subreq = aead_request_ctx(req);
 680        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 681        struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
 682        struct crypto_aead *child = ctx->child;
 683        u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
 684                           crypto_aead_alignmask(child) + 1);
 685
 686        /* L' */
 687        iv[0] = 3;
 688
 689        memcpy(iv + 1, ctx->nonce, 3);
 690        memcpy(iv + 4, req->iv, 8);
 691
 692        aead_request_set_tfm(subreq, child);
 693        aead_request_set_callback(subreq, req->base.flags, req->base.complete,
 694                                  req->base.data);
 695        aead_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, iv);
 696        aead_request_set_assoc(subreq, req->assoc, req->assoclen);
 697
 698        return subreq;
 699}
 700
 701static int crypto_rfc4309_encrypt(struct aead_request *req)
 702{
 703        req = crypto_rfc4309_crypt(req);
 704
 705        return crypto_aead_encrypt(req);
 706}
 707
 708static int crypto_rfc4309_decrypt(struct aead_request *req)
 709{
 710        req = crypto_rfc4309_crypt(req);
 711
 712        return crypto_aead_decrypt(req);
 713}
 714
 715static int crypto_rfc4309_init_tfm(struct crypto_tfm *tfm)
 716{
 717        struct crypto_instance *inst = (void *)tfm->__crt_alg;
 718        struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst);
 719        struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
 720        struct crypto_aead *aead;
 721        unsigned long align;
 722
 723        aead = crypto_spawn_aead(spawn);
 724        if (IS_ERR(aead))
 725                return PTR_ERR(aead);
 726
 727        ctx->child = aead;
 728
 729        align = crypto_aead_alignmask(aead);
 730        align &= ~(crypto_tfm_ctx_alignment() - 1);
 731        tfm->crt_aead.reqsize = sizeof(struct aead_request) +
 732                                ALIGN(crypto_aead_reqsize(aead),
 733                                      crypto_tfm_ctx_alignment()) +
 734                                align + 16;
 735
 736        return 0;
 737}
 738
 739static void crypto_rfc4309_exit_tfm(struct crypto_tfm *tfm)
 740{
 741        struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
 742
 743        crypto_free_aead(ctx->child);
 744}
 745
 746static struct crypto_instance *crypto_rfc4309_alloc(struct rtattr **tb)
 747{
 748        struct crypto_attr_type *algt;
 749        struct crypto_instance *inst;
 750        struct crypto_aead_spawn *spawn;
 751        struct crypto_alg *alg;
 752        const char *ccm_name;
 753        int err;
 754
 755        algt = crypto_get_attr_type(tb);
 756        if (IS_ERR(algt))
 757                return ERR_CAST(algt);
 758
 759        if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 760                return ERR_PTR(-EINVAL);
 761
 762        ccm_name = crypto_attr_alg_name(tb[1]);
 763        if (IS_ERR(ccm_name))
 764                return ERR_CAST(ccm_name);
 765
 766        inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 767        if (!inst)
 768                return ERR_PTR(-ENOMEM);
 769
 770        spawn = crypto_instance_ctx(inst);
 771        crypto_set_aead_spawn(spawn, inst);
 772        err = crypto_grab_aead(spawn, ccm_name, 0,
 773                               crypto_requires_sync(algt->type, algt->mask));
 774        if (err)
 775                goto out_free_inst;
 776
 777        alg = crypto_aead_spawn_alg(spawn);
 778
 779        err = -EINVAL;
 780
 781        /* We only support 16-byte blocks. */
 782        if (alg->cra_aead.ivsize != 16)
 783                goto out_drop_alg;
 784
 785        /* Not a stream cipher? */
 786        if (alg->cra_blocksize != 1)
 787                goto out_drop_alg;
 788
 789        err = -ENAMETOOLONG;
 790        if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
 791                     "rfc4309(%s)", alg->cra_name) >= CRYPTO_MAX_ALG_NAME ||
 792            snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 793                     "rfc4309(%s)", alg->cra_driver_name) >=
 794            CRYPTO_MAX_ALG_NAME)
 795                goto out_drop_alg;
 796
 797        inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
 798        inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
 799        inst->alg.cra_priority = alg->cra_priority;
 800        inst->alg.cra_blocksize = 1;
 801        inst->alg.cra_alignmask = alg->cra_alignmask;
 802        inst->alg.cra_type = &crypto_nivaead_type;
 803
 804        inst->alg.cra_aead.ivsize = 8;
 805        inst->alg.cra_aead.maxauthsize = 16;
 806
 807        inst->alg.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);
 808
 809        inst->alg.cra_init = crypto_rfc4309_init_tfm;
 810        inst->alg.cra_exit = crypto_rfc4309_exit_tfm;
 811
 812        inst->alg.cra_aead.setkey = crypto_rfc4309_setkey;
 813        inst->alg.cra_aead.setauthsize = crypto_rfc4309_setauthsize;
 814        inst->alg.cra_aead.encrypt = crypto_rfc4309_encrypt;
 815        inst->alg.cra_aead.decrypt = crypto_rfc4309_decrypt;
 816
 817        inst->alg.cra_aead.geniv = "seqiv";
 818
 819out:
 820        return inst;
 821
 822out_drop_alg:
 823        crypto_drop_aead(spawn);
 824out_free_inst:
 825        kfree(inst);
 826        inst = ERR_PTR(err);
 827        goto out;
 828}
 829
 830static void crypto_rfc4309_free(struct crypto_instance *inst)
 831{
 832        crypto_drop_spawn(crypto_instance_ctx(inst));
 833        kfree(inst);
 834}
 835
 836static struct crypto_template crypto_rfc4309_tmpl = {
 837        .name = "rfc4309",
 838        .alloc = crypto_rfc4309_alloc,
 839        .free = crypto_rfc4309_free,
 840        .module = THIS_MODULE,
 841};
 842
 843static int __init crypto_ccm_module_init(void)
 844{
 845        int err;
 846
 847        err = crypto_register_template(&crypto_ccm_base_tmpl);
 848        if (err)
 849                goto out;
 850
 851        err = crypto_register_template(&crypto_ccm_tmpl);
 852        if (err)
 853                goto out_undo_base;
 854
 855        err = crypto_register_template(&crypto_rfc4309_tmpl);
 856        if (err)
 857                goto out_undo_ccm;
 858
 859out:
 860        return err;
 861
 862out_undo_ccm:
 863        crypto_unregister_template(&crypto_ccm_tmpl);
 864out_undo_base:
 865        crypto_unregister_template(&crypto_ccm_base_tmpl);
 866        goto out;
 867}
 868
 869static void __exit crypto_ccm_module_exit(void)
 870{
 871        crypto_unregister_template(&crypto_rfc4309_tmpl);
 872        crypto_unregister_template(&crypto_ccm_tmpl);
 873        crypto_unregister_template(&crypto_ccm_base_tmpl);
 874}
 875
 876module_init(crypto_ccm_module_init);
 877module_exit(crypto_ccm_module_exit);
 878
 879MODULE_LICENSE("GPL");
 880MODULE_DESCRIPTION("Counter with CBC MAC");
 881MODULE_ALIAS("ccm_base");
 882MODULE_ALIAS("rfc4309");
 883
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