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, 0);
 220
 221                compute_mac(tfm, data_src, n, pctx);
 222                len -= n;
 223
 224                scatterwalk_unmap(data_src, 0);
 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        }
 270
 271        /* compute plaintext into mac */
 272        get_data_to_compute(cipher, pctx, plain, cryptlen);
 273
 274out:
 275        return err;
 276}
 277
 278static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err)
 279{
 280        struct aead_request *req = areq->data;
 281        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 282        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 283        u8 *odata = pctx->odata;
 284
 285        if (!err)
 286                scatterwalk_map_and_copy(odata, req->dst, req->cryptlen,
 287                                         crypto_aead_authsize(aead), 1);
 288        aead_request_complete(req, err);
 289}
 290
 291static inline int crypto_ccm_check_iv(const u8 *iv)
 292{
 293        /* 2 <= L <= 8, so 1 <= L' <= 7. */
 294        if (1 > iv[0] || iv[0] > 7)
 295                return -EINVAL;
 296
 297        return 0;
 298}
 299
 300static int crypto_ccm_encrypt(struct aead_request *req)
 301{
 302        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 303        struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
 304        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 305        struct ablkcipher_request *abreq = &pctx->abreq;
 306        struct scatterlist *dst;
 307        unsigned int cryptlen = req->cryptlen;
 308        u8 *odata = pctx->odata;
 309        u8 *iv = req->iv;
 310        int err;
 311
 312        err = crypto_ccm_check_iv(iv);
 313        if (err)
 314                return err;
 315
 316        pctx->flags = aead_request_flags(req);
 317
 318        err = crypto_ccm_auth(req, req->src, cryptlen);
 319        if (err)
 320                return err;
 321
 322         /* Note: rfc 3610 and NIST 800-38C require counter of
 323         * zero to encrypt auth tag.
 324         */
 325        memset(iv + 15 - iv[0], 0, iv[0] + 1);
 326
 327        sg_init_table(pctx->src, 2);
 328        sg_set_buf(pctx->src, odata, 16);
 329        scatterwalk_sg_chain(pctx->src, 2, req->src);
 330
 331        dst = pctx->src;
 332        if (req->src != req->dst) {
 333                sg_init_table(pctx->dst, 2);
 334                sg_set_buf(pctx->dst, odata, 16);
 335                scatterwalk_sg_chain(pctx->dst, 2, req->dst);
 336                dst = pctx->dst;
 337        }
 338
 339        ablkcipher_request_set_tfm(abreq, ctx->ctr);
 340        ablkcipher_request_set_callback(abreq, pctx->flags,
 341                                        crypto_ccm_encrypt_done, req);
 342        ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
 343        err = crypto_ablkcipher_encrypt(abreq);
 344        if (err)
 345                return err;
 346
 347        /* copy authtag to end of dst */
 348        scatterwalk_map_and_copy(odata, req->dst, cryptlen,
 349                                 crypto_aead_authsize(aead), 1);
 350        return err;
 351}
 352
 353static void crypto_ccm_decrypt_done(struct crypto_async_request *areq,
 354                                   int err)
 355{
 356        struct aead_request *req = areq->data;
 357        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 358        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 359        unsigned int authsize = crypto_aead_authsize(aead);
 360        unsigned int cryptlen = req->cryptlen - authsize;
 361
 362        if (!err) {
 363                err = crypto_ccm_auth(req, req->dst, cryptlen);
 364                if (!err && memcmp(pctx->auth_tag, pctx->odata, authsize))
 365                        err = -EBADMSG;
 366        }
 367        aead_request_complete(req, err);
 368}
 369
 370static int crypto_ccm_decrypt(struct aead_request *req)
 371{
 372        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 373        struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
 374        struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
 375        struct ablkcipher_request *abreq = &pctx->abreq;
 376        struct scatterlist *dst;
 377        unsigned int authsize = crypto_aead_authsize(aead);
 378        unsigned int cryptlen = req->cryptlen;
 379        u8 *authtag = pctx->auth_tag;
 380        u8 *odata = pctx->odata;
 381        u8 *iv = req->iv;
 382        int err;
 383
 384        if (cryptlen < authsize)
 385                return -EINVAL;
 386        cryptlen -= authsize;
 387
 388        err = crypto_ccm_check_iv(iv);
 389        if (err)
 390                return err;
 391
 392        pctx->flags = aead_request_flags(req);
 393
 394        scatterwalk_map_and_copy(authtag, req->src, cryptlen, authsize, 0);
 395
 396        memset(iv + 15 - iv[0], 0, iv[0] + 1);
 397
 398        sg_init_table(pctx->src, 2);
 399        sg_set_buf(pctx->src, authtag, 16);
 400        scatterwalk_sg_chain(pctx->src, 2, req->src);
 401
 402        dst = pctx->src;
 403        if (req->src != req->dst) {
 404                sg_init_table(pctx->dst, 2);
 405                sg_set_buf(pctx->dst, authtag, 16);
 406                scatterwalk_sg_chain(pctx->dst, 2, req->dst);
 407                dst = pctx->dst;
 408        }
 409
 410        ablkcipher_request_set_tfm(abreq, ctx->ctr);
 411        ablkcipher_request_set_callback(abreq, pctx->flags,
 412                                        crypto_ccm_decrypt_done, req);
 413        ablkcipher_request_set_crypt(abreq, pctx->src, dst, cryptlen + 16, iv);
 414        err = crypto_ablkcipher_decrypt(abreq);
 415        if (err)
 416                return err;
 417
 418        err = crypto_ccm_auth(req, req->dst, cryptlen);
 419        if (err)
 420                return err;
 421
 422        /* verify */
 423        if (memcmp(authtag, odata, authsize))
 424                return -EBADMSG;
 425
 426        return err;
 427}
 428
 429static int crypto_ccm_init_tfm(struct crypto_tfm *tfm)
 430{
 431        struct crypto_instance *inst = (void *)tfm->__crt_alg;
 432        struct ccm_instance_ctx *ictx = crypto_instance_ctx(inst);
 433        struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
 434        struct crypto_cipher *cipher;
 435        struct crypto_ablkcipher *ctr;
 436        unsigned long align;
 437        int err;
 438
 439        cipher = crypto_spawn_cipher(&ictx->cipher);
 440        if (IS_ERR(cipher))
 441                return PTR_ERR(cipher);
 442
 443        ctr = crypto_spawn_skcipher(&ictx->ctr);
 444        err = PTR_ERR(ctr);
 445        if (IS_ERR(ctr))
 446                goto err_free_cipher;
 447
 448        ctx->cipher = cipher;
 449        ctx->ctr = ctr;
 450
 451        align = crypto_tfm_alg_alignmask(tfm);
 452        align &= ~(crypto_tfm_ctx_alignment() - 1);
 453        tfm->crt_aead.reqsize = align +
 454                                sizeof(struct crypto_ccm_req_priv_ctx) +
 455                                crypto_ablkcipher_reqsize(ctr);
 456
 457        return 0;
 458
 459err_free_cipher:
 460        crypto_free_cipher(cipher);
 461        return err;
 462}
 463
 464static void crypto_ccm_exit_tfm(struct crypto_tfm *tfm)
 465{
 466        struct crypto_ccm_ctx *ctx = crypto_tfm_ctx(tfm);
 467
 468        crypto_free_cipher(ctx->cipher);
 469        crypto_free_ablkcipher(ctx->ctr);
 470}
 471
 472static struct crypto_instance *crypto_ccm_alloc_common(struct rtattr **tb,
 473                                                       const char *full_name,
 474                                                       const char *ctr_name,
 475                                                       const char *cipher_name)
 476{
 477        struct crypto_attr_type *algt;
 478        struct crypto_instance *inst;
 479        struct crypto_alg *ctr;
 480        struct crypto_alg *cipher;
 481        struct ccm_instance_ctx *ictx;
 482        int err;
 483
 484        algt = crypto_get_attr_type(tb);
 485        err = PTR_ERR(algt);
 486        if (IS_ERR(algt))
 487                return ERR_PTR(err);
 488
 489        if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 490                return ERR_PTR(-EINVAL);
 491
 492        cipher = crypto_alg_mod_lookup(cipher_name,  CRYPTO_ALG_TYPE_CIPHER,
 493                                       CRYPTO_ALG_TYPE_MASK);
 494        err = PTR_ERR(cipher);
 495        if (IS_ERR(cipher))
 496                return ERR_PTR(err);
 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        int err;
 575        const char *cipher_name;
 576        char ctr_name[CRYPTO_MAX_ALG_NAME];
 577        char full_name[CRYPTO_MAX_ALG_NAME];
 578
 579        cipher_name = crypto_attr_alg_name(tb[1]);
 580        err = PTR_ERR(cipher_name);
 581        if (IS_ERR(cipher_name))
 582                return ERR_PTR(err);
 583
 584        if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
 585                     cipher_name) >= CRYPTO_MAX_ALG_NAME)
 586                return ERR_PTR(-ENAMETOOLONG);
 587
 588        if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >=
 589            CRYPTO_MAX_ALG_NAME)
 590                return ERR_PTR(-ENAMETOOLONG);
 591
 592        return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
 593}
 594
 595static void crypto_ccm_free(struct crypto_instance *inst)
 596{
 597        struct ccm_instance_ctx *ctx = crypto_instance_ctx(inst);
 598
 599        crypto_drop_spawn(&ctx->cipher);
 600        crypto_drop_skcipher(&ctx->ctr);
 601        kfree(inst);
 602}
 603
 604static struct crypto_template crypto_ccm_tmpl = {
 605        .name = "ccm",
 606        .alloc = crypto_ccm_alloc,
 607        .free = crypto_ccm_free,
 608        .module = THIS_MODULE,
 609};
 610
 611static struct crypto_instance *crypto_ccm_base_alloc(struct rtattr **tb)
 612{
 613        int err;
 614        const char *ctr_name;
 615        const char *cipher_name;
 616        char full_name[CRYPTO_MAX_ALG_NAME];
 617
 618        ctr_name = crypto_attr_alg_name(tb[1]);
 619        err = PTR_ERR(ctr_name);
 620        if (IS_ERR(ctr_name))
 621                return ERR_PTR(err);
 622
 623        cipher_name = crypto_attr_alg_name(tb[2]);
 624        err = PTR_ERR(cipher_name);
 625        if (IS_ERR(cipher_name))
 626                return ERR_PTR(err);
 627
 628        if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)",
 629                     ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME)
 630                return ERR_PTR(-ENAMETOOLONG);
 631
 632        return crypto_ccm_alloc_common(tb, full_name, ctr_name, cipher_name);
 633}
 634
 635static struct crypto_template crypto_ccm_base_tmpl = {
 636        .name = "ccm_base",
 637        .alloc = crypto_ccm_base_alloc,
 638        .free = crypto_ccm_free,
 639        .module = THIS_MODULE,
 640};
 641
 642static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
 643                                 unsigned int keylen)
 644{
 645        struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
 646        struct crypto_aead *child = ctx->child;
 647        int err;
 648
 649        if (keylen < 3)
 650                return -EINVAL;
 651
 652        keylen -= 3;
 653        memcpy(ctx->nonce, key + keylen, 3);
 654
 655        crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
 656        crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
 657                                     CRYPTO_TFM_REQ_MASK);
 658        err = crypto_aead_setkey(child, key, keylen);
 659        crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
 660                                      CRYPTO_TFM_RES_MASK);
 661
 662        return err;
 663}
 664
 665static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
 666                                      unsigned int authsize)
 667{
 668        struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
 669
 670        switch (authsize) {
 671        case 8:
 672        case 12:
 673        case 16:
 674                break;
 675        default:
 676                return -EINVAL;
 677        }
 678
 679        return crypto_aead_setauthsize(ctx->child, authsize);
 680}
 681
 682static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
 683{
 684        struct aead_request *subreq = aead_request_ctx(req);
 685        struct crypto_aead *aead = crypto_aead_reqtfm(req);
 686        struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
 687        struct crypto_aead *child = ctx->child;
 688        u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
 689                           crypto_aead_alignmask(child) + 1);
 690
 691        /* L' */
 692        iv[0] = 3;
 693
 694        memcpy(iv + 1, ctx->nonce, 3);
 695        memcpy(iv + 4, req->iv, 8);
 696
 697        aead_request_set_tfm(subreq, child);
 698        aead_request_set_callback(subreq, req->base.flags, req->base.complete,
 699                                  req->base.data);
 700        aead_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, iv);
 701        aead_request_set_assoc(subreq, req->assoc, req->assoclen);
 702
 703        return subreq;
 704}
 705
 706static int crypto_rfc4309_encrypt(struct aead_request *req)
 707{
 708        req = crypto_rfc4309_crypt(req);
 709
 710        return crypto_aead_encrypt(req);
 711}
 712
 713static int crypto_rfc4309_decrypt(struct aead_request *req)
 714{
 715        req = crypto_rfc4309_crypt(req);
 716
 717        return crypto_aead_decrypt(req);
 718}
 719
 720static int crypto_rfc4309_init_tfm(struct crypto_tfm *tfm)
 721{
 722        struct crypto_instance *inst = (void *)tfm->__crt_alg;
 723        struct crypto_aead_spawn *spawn = crypto_instance_ctx(inst);
 724        struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
 725        struct crypto_aead *aead;
 726        unsigned long align;
 727
 728        aead = crypto_spawn_aead(spawn);
 729        if (IS_ERR(aead))
 730                return PTR_ERR(aead);
 731
 732        ctx->child = aead;
 733
 734        align = crypto_aead_alignmask(aead);
 735        align &= ~(crypto_tfm_ctx_alignment() - 1);
 736        tfm->crt_aead.reqsize = sizeof(struct aead_request) +
 737                                ALIGN(crypto_aead_reqsize(aead),
 738                                      crypto_tfm_ctx_alignment()) +
 739                                align + 16;
 740
 741        return 0;
 742}
 743
 744static void crypto_rfc4309_exit_tfm(struct crypto_tfm *tfm)
 745{
 746        struct crypto_rfc4309_ctx *ctx = crypto_tfm_ctx(tfm);
 747
 748        crypto_free_aead(ctx->child);
 749}
 750
 751static struct crypto_instance *crypto_rfc4309_alloc(struct rtattr **tb)
 752{
 753        struct crypto_attr_type *algt;
 754        struct crypto_instance *inst;
 755        struct crypto_aead_spawn *spawn;
 756        struct crypto_alg *alg;
 757        const char *ccm_name;
 758        int err;
 759
 760        algt = crypto_get_attr_type(tb);
 761        err = PTR_ERR(algt);
 762        if (IS_ERR(algt))
 763                return ERR_PTR(err);
 764
 765        if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 766                return ERR_PTR(-EINVAL);
 767
 768        ccm_name = crypto_attr_alg_name(tb[1]);
 769        err = PTR_ERR(ccm_name);
 770        if (IS_ERR(ccm_name))
 771                return ERR_PTR(err);
 772
 773        inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 774        if (!inst)
 775                return ERR_PTR(-ENOMEM);
 776
 777        spawn = crypto_instance_ctx(inst);
 778        crypto_set_aead_spawn(spawn, inst);
 779        err = crypto_grab_aead(spawn, ccm_name, 0,
 780                               crypto_requires_sync(algt->type, algt->mask));
 781        if (err)
 782                goto out_free_inst;
 783
 784        alg = crypto_aead_spawn_alg(spawn);
 785
 786        err = -EINVAL;
 787
 788        /* We only support 16-byte blocks. */
 789        if (alg->cra_aead.ivsize != 16)
 790                goto out_drop_alg;
 791
 792        /* Not a stream cipher? */
 793        if (alg->cra_blocksize != 1)
 794                goto out_drop_alg;
 795
 796        err = -ENAMETOOLONG;
 797        if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME,
 798                     "rfc4309(%s)", alg->cra_name) >= CRYPTO_MAX_ALG_NAME ||
 799            snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 800                     "rfc4309(%s)", alg->cra_driver_name) >=
 801            CRYPTO_MAX_ALG_NAME)
 802                goto out_drop_alg;
 803
 804        inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD;
 805        inst->alg.cra_flags |= alg->cra_flags & CRYPTO_ALG_ASYNC;
 806        inst->alg.cra_priority = alg->cra_priority;
 807        inst->alg.cra_blocksize = 1;
 808        inst->alg.cra_alignmask = alg->cra_alignmask;
 809        inst->alg.cra_type = &crypto_nivaead_type;
 810
 811        inst->alg.cra_aead.ivsize = 8;
 812        inst->alg.cra_aead.maxauthsize = 16;
 813
 814        inst->alg.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);
 815
 816        inst->alg.cra_init = crypto_rfc4309_init_tfm;
 817        inst->alg.cra_exit = crypto_rfc4309_exit_tfm;
 818
 819        inst->alg.cra_aead.setkey = crypto_rfc4309_setkey;
 820        inst->alg.cra_aead.setauthsize = crypto_rfc4309_setauthsize;
 821        inst->alg.cra_aead.encrypt = crypto_rfc4309_encrypt;
 822        inst->alg.cra_aead.decrypt = crypto_rfc4309_decrypt;
 823
 824        inst->alg.cra_aead.geniv = "seqiv";
 825
 826out:
 827        return inst;
 828
 829out_drop_alg:
 830        crypto_drop_aead(spawn);
 831out_free_inst:
 832        kfree(inst);
 833        inst = ERR_PTR(err);
 834        goto out;
 835}
 836
 837static void crypto_rfc4309_free(struct crypto_instance *inst)
 838{
 839        crypto_drop_spawn(crypto_instance_ctx(inst));
 840        kfree(inst);
 841}
 842
 843static struct crypto_template crypto_rfc4309_tmpl = {
 844        .name = "rfc4309",
 845        .alloc = crypto_rfc4309_alloc,
 846        .free = crypto_rfc4309_free,
 847        .module = THIS_MODULE,
 848};
 849
 850static int __init crypto_ccm_module_init(void)
 851{
 852        int err;
 853
 854        err = crypto_register_template(&crypto_ccm_base_tmpl);
 855        if (err)
 856                goto out;
 857
 858        err = crypto_register_template(&crypto_ccm_tmpl);
 859        if (err)
 860                goto out_undo_base;
 861
 862        err = crypto_register_template(&crypto_rfc4309_tmpl);
 863        if (err)
 864                goto out_undo_ccm;
 865
 866out:
 867        return err;
 868
 869out_undo_ccm:
 870        crypto_unregister_template(&crypto_ccm_tmpl);
 871out_undo_base:
 872        crypto_unregister_template(&crypto_ccm_base_tmpl);
 873        goto out;
 874}
 875
 876static void __exit crypto_ccm_module_exit(void)
 877{
 878        crypto_unregister_template(&crypto_rfc4309_tmpl);
 879        crypto_unregister_template(&crypto_ccm_tmpl);
 880        crypto_unregister_template(&crypto_ccm_base_tmpl);
 881}
 882
 883module_init(crypto_ccm_module_init);
 884module_exit(crypto_ccm_module_exit);
 885
 886MODULE_LICENSE("GPL");
 887MODULE_DESCRIPTION("Counter with CBC MAC");
 888MODULE_ALIAS("ccm_base");
 889MODULE_ALIAS("rfc4309");
 890