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