crypto/authencesn.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * authencesn.c - AEAD wrapper for IPsec with extended sequence numbers,
   4  *                 derived from authenc.c
   5  *
   6  * Copyright (C) 2010 secunet Security Networks AG
   7  * Copyright (C) 2010 Steffen Klassert <steffen.klassert@secunet.com>
   8  * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
   9  */
  10
  11 #include <crypto/internal/aead.h>
  12 #include <crypto/internal/hash.h>
  13 #include <crypto/internal/skcipher.h>
  14 #include <crypto/authenc.h>
  15 #include <crypto/null.h>
  16 #include <crypto/scatterwalk.h>
  17 #include <linux/err.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/rtnetlink.h>
  22 #include <linux/slab.h>
  23 #include <linux/spinlock.h>
  24
  25 struct authenc_esn_instance_ctx {
  26         struct crypto_ahash_spawn auth;
  27         struct crypto_skcipher_spawn enc;
  28 };
  29
  30 struct crypto_authenc_esn_ctx {
  31         unsigned int reqoff;
  32         struct crypto_ahash *auth;
  33         struct crypto_skcipher *enc;
  34         struct crypto_sync_skcipher *null;
  35 };
  36
  37 struct authenc_esn_request_ctx {
  38         struct scatterlist src[2];
  39         struct scatterlist dst[2];
  40         char tail[];
  41 };
  42
  43 static void authenc_esn_request_complete(struct aead_request *req, int err)
  44 {
  45         if (err != -EINPROGRESS)
  46                 aead_request_complete(req, err);
  47 }
  48
  49 static int crypto_authenc_esn_setauthsize(struct crypto_aead *authenc_esn,
  50                                           unsigned int authsize)
  51 {
  52         if (authsize > 0 && authsize < 4)
  53                 return -EINVAL;
  54
  55         return 0;
  56 }
  57
  58 static int crypto_authenc_esn_setkey(struct crypto_aead *authenc_esn, const u8 *key,
  59                                      unsigned int keylen)
  60 {
  61         struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
  62         struct crypto_ahash *auth = ctx->auth;
  63         struct crypto_skcipher *enc = ctx->enc;
  64         struct crypto_authenc_keys keys;
  65         int err = -EINVAL;
  66
  67         if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
  68                 goto badkey;
  69
  70         crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
  71         crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc_esn) &
  72                                      CRYPTO_TFM_REQ_MASK);
  73         err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
  74         crypto_aead_set_flags(authenc_esn, crypto_ahash_get_flags(auth) &
  75                                            CRYPTO_TFM_RES_MASK);
  76
  77         if (err)
  78                 goto out;
  79
  80         crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
  81         crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc_esn) &
  82                                          CRYPTO_TFM_REQ_MASK);
  83         err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen);
  84         crypto_aead_set_flags(authenc_esn, crypto_skcipher_get_flags(enc) &
  85                                            CRYPTO_TFM_RES_MASK);
  86
  87 out:
  88         memzero_explicit(&keys, sizeof(keys));
  89         return err;
  90
  91 badkey:
  92         crypto_aead_set_flags(authenc_esn, CRYPTO_TFM_RES_BAD_KEY_LEN);
  93         goto out;
  94 }
  95
  96 static int crypto_authenc_esn_genicv_tail(struct aead_request *req,
  97                                           unsigned int flags)
  98 {
  99         struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 100         struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 101         struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
 102         struct crypto_ahash *auth = ctx->auth;
 103         u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
 104                              crypto_ahash_alignmask(auth) + 1);
 105         unsigned int authsize = crypto_aead_authsize(authenc_esn);
 106         unsigned int assoclen = req->assoclen;
 107         unsigned int cryptlen = req->cryptlen;
 108         struct scatterlist *dst = req->dst;
 109         u32 tmp[2];
 110
 111         /* Move high-order bits of sequence number back. */
 112         scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
 113         scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
 114         scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
 115
 116         scatterwalk_map_and_copy(hash, dst, assoclen + cryptlen, authsize, 1);
 117         return 0;
 118 }
 119
 120 static void authenc_esn_geniv_ahash_done(struct crypto_async_request *areq,
 121                                          int err)
 122 {
 123         struct aead_request *req = areq->data;
 124
 125         err = err ?: crypto_authenc_esn_genicv_tail(req, 0);
 126         aead_request_complete(req, err);
 127 }
 128
 129 static int crypto_authenc_esn_genicv(struct aead_request *req,
 130                                      unsigned int flags)
 131 {
 132         struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 133         struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
 134         struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 135         struct crypto_ahash *auth = ctx->auth;
 136         u8 *hash = PTR_ALIGN((u8 *)areq_ctx->tail,
 137                              crypto_ahash_alignmask(auth) + 1);
 138         struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
 139         unsigned int authsize = crypto_aead_authsize(authenc_esn);
 140         unsigned int assoclen = req->assoclen;
 141         unsigned int cryptlen = req->cryptlen;
 142         struct scatterlist *dst = req->dst;
 143         u32 tmp[2];
 144
 145         if (!authsize)
 146                 return 0;
 147
 148         /* Move high-order bits of sequence number to the end. */
 149         scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
 150         scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
 151         scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
 152
 153         sg_init_table(areq_ctx->dst, 2);
 154         dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
 155
 156         ahash_request_set_tfm(ahreq, auth);
 157         ahash_request_set_crypt(ahreq, dst, hash, assoclen + cryptlen);
 158         ahash_request_set_callback(ahreq, flags,
 159                                    authenc_esn_geniv_ahash_done, req);
 160
 161         return crypto_ahash_digest(ahreq) ?:
 162                crypto_authenc_esn_genicv_tail(req, aead_request_flags(req));
 163 }
 164
 165
 166 static void crypto_authenc_esn_encrypt_done(struct crypto_async_request *req,
 167                                             int err)
 168 {
 169         struct aead_request *areq = req->data;
 170
 171         if (!err)
 172                 err = crypto_authenc_esn_genicv(areq, 0);
 173
 174         authenc_esn_request_complete(areq, err);
 175 }
 176
 177 static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
 178 {
 179         struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 180         struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 181         SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
 182
 183         skcipher_request_set_sync_tfm(skreq, ctx->null);
 184         skcipher_request_set_callback(skreq, aead_request_flags(req),
 185                                       NULL, NULL);
 186         skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL);
 187
 188         return crypto_skcipher_encrypt(skreq);
 189 }
 190
 191 static int crypto_authenc_esn_encrypt(struct aead_request *req)
 192 {
 193         struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 194         struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
 195         struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 196         struct skcipher_request *skreq = (void *)(areq_ctx->tail +
 197                                                   ctx->reqoff);
 198         struct crypto_skcipher *enc = ctx->enc;
 199         unsigned int assoclen = req->assoclen;
 200         unsigned int cryptlen = req->cryptlen;
 201         struct scatterlist *src, *dst;
 202         int err;
 203
 204         sg_init_table(areq_ctx->src, 2);
 205         src = scatterwalk_ffwd(areq_ctx->src, req->src, assoclen);
 206         dst = src;
 207
 208         if (req->src != req->dst) {
 209                 err = crypto_authenc_esn_copy(req, assoclen);
 210                 if (err)
 211                         return err;
 212
 213                 sg_init_table(areq_ctx->dst, 2);
 214                 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
 215         }
 216
 217         skcipher_request_set_tfm(skreq, enc);
 218         skcipher_request_set_callback(skreq, aead_request_flags(req),
 219                                       crypto_authenc_esn_encrypt_done, req);
 220         skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
 221
 222         err = crypto_skcipher_encrypt(skreq);
 223         if (err)
 224                 return err;
 225
 226         return crypto_authenc_esn_genicv(req, aead_request_flags(req));
 227 }
 228
 229 static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
 230                                            unsigned int flags)
 231 {
 232         struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 233         unsigned int authsize = crypto_aead_authsize(authenc_esn);
 234         struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
 235         struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 236         struct skcipher_request *skreq = (void *)(areq_ctx->tail +
 237                                                   ctx->reqoff);
 238         struct crypto_ahash *auth = ctx->auth;
 239         u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
 240                               crypto_ahash_alignmask(auth) + 1);
 241         unsigned int cryptlen = req->cryptlen - authsize;
 242         unsigned int assoclen = req->assoclen;
 243         struct scatterlist *dst = req->dst;
 244         u8 *ihash = ohash + crypto_ahash_digestsize(auth);
 245         u32 tmp[2];
 246
 247         if (!authsize)
 248                 goto decrypt;
 249
 250         /* Move high-order bits of sequence number back. */
 251         scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
 252         scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
 253         scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
 254
 255         if (crypto_memneq(ihash, ohash, authsize))
 256                 return -EBADMSG;
 257
 258 decrypt:
 259
 260         sg_init_table(areq_ctx->dst, 2);
 261         dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);
 262
 263         skcipher_request_set_tfm(skreq, ctx->enc);
 264         skcipher_request_set_callback(skreq, flags,
 265                                       req->base.complete, req->base.data);
 266         skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv);
 267
 268         return crypto_skcipher_decrypt(skreq);
 269 }
 270
 271 static void authenc_esn_verify_ahash_done(struct crypto_async_request *areq,
 272                                           int err)
 273 {
 274         struct aead_request *req = areq->data;
 275
 276         err = err ?: crypto_authenc_esn_decrypt_tail(req, 0);
 277         authenc_esn_request_complete(req, err);
 278 }
 279
 280 static int crypto_authenc_esn_decrypt(struct aead_request *req)
 281 {
 282         struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 283         struct authenc_esn_request_ctx *areq_ctx = aead_request_ctx(req);
 284         struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
 285         struct ahash_request *ahreq = (void *)(areq_ctx->tail + ctx->reqoff);
 286         unsigned int authsize = crypto_aead_authsize(authenc_esn);
 287         struct crypto_ahash *auth = ctx->auth;
 288         u8 *ohash = PTR_ALIGN((u8 *)areq_ctx->tail,
 289                               crypto_ahash_alignmask(auth) + 1);
 290         unsigned int assoclen = req->assoclen;
 291         unsigned int cryptlen = req->cryptlen;
 292         u8 *ihash = ohash + crypto_ahash_digestsize(auth);
 293         struct scatterlist *dst = req->dst;
 294         u32 tmp[2];
 295         int err;
 296
 297         cryptlen -= authsize;
 298
 299         if (req->src != dst) {
 300                 err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
 301                 if (err)
 302                         return err;
 303         }
 304
 305         scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
 306                                  authsize, 0);
 307
 308         if (!authsize)
 309                 goto tail;
 310
 311         /* Move high-order bits of sequence number to the end. */
 312         scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
 313         scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
 314         scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
 315
 316         sg_init_table(areq_ctx->dst, 2);
 317         dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
 318
 319         ahash_request_set_tfm(ahreq, auth);
 320         ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
 321         ahash_request_set_callback(ahreq, aead_request_flags(req),
 322                                    authenc_esn_verify_ahash_done, req);
 323
 324         err = crypto_ahash_digest(ahreq);
 325         if (err)
 326                 return err;
 327
 328 tail:
 329         return crypto_authenc_esn_decrypt_tail(req, aead_request_flags(req));
 330 }
 331
 332 static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
 333 {
 334         struct aead_instance *inst = aead_alg_instance(tfm);
 335         struct authenc_esn_instance_ctx *ictx = aead_instance_ctx(inst);
 336         struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
 337         struct crypto_ahash *auth;
 338         struct crypto_skcipher *enc;
 339         struct crypto_sync_skcipher *null;
 340         int err;
 341
 342         auth = crypto_spawn_ahash(&ictx->auth);
 343         if (IS_ERR(auth))
 344                 return PTR_ERR(auth);
 345
 346         enc = crypto_spawn_skcipher(&ictx->enc);
 347         err = PTR_ERR(enc);
 348         if (IS_ERR(enc))
 349                 goto err_free_ahash;
 350
 351         null = crypto_get_default_null_skcipher();
 352         err = PTR_ERR(null);
 353         if (IS_ERR(null))
 354                 goto err_free_skcipher;
 355
 356         ctx->auth = auth;
 357         ctx->enc = enc;
 358         ctx->null = null;
 359
 360         ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth),
 361                             crypto_ahash_alignmask(auth) + 1);
 362
 363         crypto_aead_set_reqsize(
 364                 tfm,
 365                 sizeof(struct authenc_esn_request_ctx) +
 366                 ctx->reqoff +
 367                 max_t(unsigned int,
 368                       crypto_ahash_reqsize(auth) +
 369                       sizeof(struct ahash_request),
 370                       sizeof(struct skcipher_request) +
 371                       crypto_skcipher_reqsize(enc)));
 372
 373         return 0;
 374
 375 err_free_skcipher:
 376         crypto_free_skcipher(enc);
 377 err_free_ahash:
 378         crypto_free_ahash(auth);
 379         return err;
 380 }
 381
 382 static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
 383 {
 384         struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
 385
 386         crypto_free_ahash(ctx->auth);
 387         crypto_free_skcipher(ctx->enc);
 388         crypto_put_default_null_skcipher();
 389 }
 390
 391 static void crypto_authenc_esn_free(struct aead_instance *inst)
 392 {
 393         struct authenc_esn_instance_ctx *ctx = aead_instance_ctx(inst);
 394
 395         crypto_drop_skcipher(&ctx->enc);
 396         crypto_drop_ahash(&ctx->auth);
 397         kfree(inst);
 398 }
 399
 400 static int crypto_authenc_esn_create(struct crypto_template *tmpl,
 401                                      struct rtattr **tb)
 402 {
 403         struct crypto_attr_type *algt;
 404         struct aead_instance *inst;
 405         struct hash_alg_common *auth;
 406         struct crypto_alg *auth_base;
 407         struct skcipher_alg *enc;
 408         struct authenc_esn_instance_ctx *ctx;
 409         const char *enc_name;
 410         int err;
 411
 412         algt = crypto_get_attr_type(tb);
 413         if (IS_ERR(algt))
 414                 return PTR_ERR(algt);
 415
 416         if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
 417                 return -EINVAL;
 418
 419         auth = ahash_attr_alg(tb[1], CRYPTO_ALG_TYPE_HASH,
 420                               CRYPTO_ALG_TYPE_AHASH_MASK |
 421                               crypto_requires_sync(algt->type, algt->mask));
 422         if (IS_ERR(auth))
 423                 return PTR_ERR(auth);
 424
 425         auth_base = &auth->base;
 426
 427         enc_name = crypto_attr_alg_name(tb[2]);
 428         err = PTR_ERR(enc_name);
 429         if (IS_ERR(enc_name))
 430                 goto out_put_auth;
 431
 432         inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
 433         err = -ENOMEM;
 434         if (!inst)
 435                 goto out_put_auth;
 436
 437         ctx = aead_instance_ctx(inst);
 438
 439         err = crypto_init_ahash_spawn(&ctx->auth, auth,
 440                                       aead_crypto_instance(inst));
 441         if (err)
 442                 goto err_free_inst;
 443
 444         crypto_set_skcipher_spawn(&ctx->enc, aead_crypto_instance(inst));
 445         err = crypto_grab_skcipher(&ctx->enc, enc_name, 0,
 446                                    crypto_requires_sync(algt->type,
 447                                                         algt->mask));
 448         if (err)
 449                 goto err_drop_auth;
 450
 451         enc = crypto_spawn_skcipher_alg(&ctx->enc);
 452
 453         err = -ENAMETOOLONG;
 454         if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
 455                      "authencesn(%s,%s)", auth_base->cra_name,
 456                      enc->base.cra_name) >= CRYPTO_MAX_ALG_NAME)
 457                 goto err_drop_enc;
 458
 459         if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
 460                      "authencesn(%s,%s)", auth_base->cra_driver_name,
 461                      enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
 462                 goto err_drop_enc;
 463
 464         inst->alg.base.cra_flags = (auth_base->cra_flags |
 465                                     enc->base.cra_flags) & CRYPTO_ALG_ASYNC;
 466         inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
 467                                       auth_base->cra_priority;
 468         inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
 469         inst->alg.base.cra_alignmask = auth_base->cra_alignmask |
 470                                        enc->base.cra_alignmask;
 471         inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_esn_ctx);
 472
 473         inst->alg.ivsize = crypto_skcipher_alg_ivsize(enc);
 474         inst->alg.chunksize = crypto_skcipher_alg_chunksize(enc);
 475         inst->alg.maxauthsize = auth->digestsize;
 476
 477         inst->alg.init = crypto_authenc_esn_init_tfm;
 478         inst->alg.exit = crypto_authenc_esn_exit_tfm;
 479
 480         inst->alg.setkey = crypto_authenc_esn_setkey;
 481         inst->alg.setauthsize = crypto_authenc_esn_setauthsize;
 482         inst->alg.encrypt = crypto_authenc_esn_encrypt;
 483         inst->alg.decrypt = crypto_authenc_esn_decrypt;
 484
 485         inst->free = crypto_authenc_esn_free,
 486
 487         err = aead_register_instance(tmpl, inst);
 488         if (err)
 489                 goto err_drop_enc;
 490
 491 out:
 492         crypto_mod_put(auth_base);
 493         return err;
 494
 495 err_drop_enc:
 496         crypto_drop_skcipher(&ctx->enc);
 497 err_drop_auth:
 498         crypto_drop_ahash(&ctx->auth);
 499 err_free_inst:
 500         kfree(inst);
 501 out_put_auth:
 502         goto out;
 503 }
 504
 505 static struct crypto_template crypto_authenc_esn_tmpl = {
 506         .name = "authencesn",
 507         .create = crypto_authenc_esn_create,
 508         .module = THIS_MODULE,
 509 };
 510
 511 static int __init crypto_authenc_esn_module_init(void)
 512 {
 513         return crypto_register_template(&crypto_authenc_esn_tmpl);
 514 }
 515
 516 static void __exit crypto_authenc_esn_module_exit(void)
 517 {
 518         crypto_unregister_template(&crypto_authenc_esn_tmpl);
 519 }
 520
 521 subsys_initcall(crypto_authenc_esn_module_init);
 522 module_exit(crypto_authenc_esn_module_exit);
 523
 524 MODULE_LICENSE("GPL");
 525 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 526 MODULE_DESCRIPTION("AEAD wrapper for IPsec with extended sequence numbers");
 527 MODULE_ALIAS_CRYPTO("authencesn");