crypto/api.c

   1 /*
   2  * Scatterlist Cryptographic API.
   3  *
   4  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   5  * Copyright (c) 2002 David S. Miller (davem@redhat.com)
   6  * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
   7  *
   8  * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
   9  * and Nettle, by Niels Möller.
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License as published by the Free
  13  * Software Foundation; either version 2 of the License, or (at your option)
  14  * any later version.
  15  *
  16  */
  17
  18 #include <linux/err.h>
  19 #include <linux/errno.h>
  20 #include <linux/kernel.h>
  21 #include <linux/kmod.h>
  22 #include <linux/module.h>
  23 #include <linux/param.h>
  24 #include <linux/sched/signal.h>
  25 #include <linux/slab.h>
  26 #include <linux/string.h>
  27 #include <linux/completion.h>
  28 #include "internal.h"
  29
  30 LIST_HEAD(crypto_alg_list);
  31 EXPORT_SYMBOL_GPL(crypto_alg_list);
  32 DECLARE_RWSEM(crypto_alg_sem);
  33 EXPORT_SYMBOL_GPL(crypto_alg_sem);
  34
  35 BLOCKING_NOTIFIER_HEAD(crypto_chain);
  36 EXPORT_SYMBOL_GPL(crypto_chain);
  37
  38 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg);
  39
  40 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
  41 {
  42         return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
  43 }
  44 EXPORT_SYMBOL_GPL(crypto_mod_get);
  45
  46 void crypto_mod_put(struct crypto_alg *alg)
  47 {
  48         struct module *module = alg->cra_module;
  49
  50         crypto_alg_put(alg);
  51         module_put(module);
  52 }
  53 EXPORT_SYMBOL_GPL(crypto_mod_put);
  54
  55 static inline int crypto_is_test_larval(struct crypto_larval *larval)
  56 {
  57         return larval->alg.cra_driver_name[0];
  58 }
  59
  60 static struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type,
  61                                               u32 mask)
  62 {
  63         struct crypto_alg *q, *alg = NULL;
  64         int best = -2;
  65
  66         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  67                 int exact, fuzzy;
  68
  69                 if (crypto_is_moribund(q))
  70                         continue;
  71
  72                 if ((q->cra_flags ^ type) & mask)
  73                         continue;
  74
  75                 if (crypto_is_larval(q) &&
  76                     !crypto_is_test_larval((struct crypto_larval *)q) &&
  77                     ((struct crypto_larval *)q)->mask != mask)
  78                         continue;
  79
  80                 exact = !strcmp(q->cra_driver_name, name);
  81                 fuzzy = !strcmp(q->cra_name, name);
  82                 if (!exact && !(fuzzy && q->cra_priority > best))
  83                         continue;
  84
  85                 if (unlikely(!crypto_mod_get(q)))
  86                         continue;
  87
  88                 best = q->cra_priority;
  89                 if (alg)
  90                         crypto_mod_put(alg);
  91                 alg = q;
  92
  93                 if (exact)
  94                         break;
  95         }
  96
  97         return alg;
  98 }
  99
 100 static void crypto_larval_destroy(struct crypto_alg *alg)
 101 {
 102         struct crypto_larval *larval = (void *)alg;
 103
 104         BUG_ON(!crypto_is_larval(alg));
 105         if (larval->adult)
 106                 crypto_mod_put(larval->adult);
 107         kfree(larval);
 108 }
 109
 110 struct crypto_larval *crypto_larval_alloc(const char *name, u32 type, u32 mask)
 111 {
 112         struct crypto_larval *larval;
 113
 114         larval = kzalloc(sizeof(*larval), GFP_KERNEL);
 115         if (!larval)
 116                 return ERR_PTR(-ENOMEM);
 117
 118         larval->mask = mask;
 119         larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
 120         larval->alg.cra_priority = -1;
 121         larval->alg.cra_destroy = crypto_larval_destroy;
 122
 123         strlcpy(larval->alg.cra_name, name, CRYPTO_MAX_ALG_NAME);
 124         init_completion(&larval->completion);
 125
 126         return larval;
 127 }
 128 EXPORT_SYMBOL_GPL(crypto_larval_alloc);
 129
 130 static struct crypto_alg *crypto_larval_add(const char *name, u32 type,
 131                                             u32 mask)
 132 {
 133         struct crypto_alg *alg;
 134         struct crypto_larval *larval;
 135
 136         larval = crypto_larval_alloc(name, type, mask);
 137         if (IS_ERR(larval))
 138                 return ERR_CAST(larval);
 139
 140         refcount_set(&larval->alg.cra_refcnt, 2);
 141
 142         down_write(&crypto_alg_sem);
 143         alg = __crypto_alg_lookup(name, type, mask);
 144         if (!alg) {
 145                 alg = &larval->alg;
 146                 list_add(&alg->cra_list, &crypto_alg_list);
 147         }
 148         up_write(&crypto_alg_sem);
 149
 150         if (alg != &larval->alg) {
 151                 kfree(larval);
 152                 if (crypto_is_larval(alg))
 153                         alg = crypto_larval_wait(alg);
 154         }
 155
 156         return alg;
 157 }
 158
 159 void crypto_larval_kill(struct crypto_alg *alg)
 160 {
 161         struct crypto_larval *larval = (void *)alg;
 162
 163         down_write(&crypto_alg_sem);
 164         list_del(&alg->cra_list);
 165         up_write(&crypto_alg_sem);
 166         complete_all(&larval->completion);
 167         crypto_alg_put(alg);
 168 }
 169 EXPORT_SYMBOL_GPL(crypto_larval_kill);
 170
 171 static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
 172 {
 173         struct crypto_larval *larval = (void *)alg;
 174         long timeout;
 175
 176         timeout = wait_for_completion_killable_timeout(
 177                 &larval->completion, 60 * HZ);
 178
 179         alg = larval->adult;
 180         if (timeout < 0)
 181                 alg = ERR_PTR(-EINTR);
 182         else if (!timeout)
 183                 alg = ERR_PTR(-ETIMEDOUT);
 184         else if (!alg)
 185                 alg = ERR_PTR(-ENOENT);
 186         else if (crypto_is_test_larval(larval) &&
 187                  !(alg->cra_flags & CRYPTO_ALG_TESTED))
 188                 alg = ERR_PTR(-EAGAIN);
 189         else if (!crypto_mod_get(alg))
 190                 alg = ERR_PTR(-EAGAIN);
 191         crypto_mod_put(&larval->alg);
 192
 193         return alg;
 194 }
 195
 196 static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
 197                                             u32 mask)
 198 {
 199         struct crypto_alg *alg;
 200         u32 test = 0;
 201
 202         if (!((type | mask) & CRYPTO_ALG_TESTED))
 203                 test |= CRYPTO_ALG_TESTED;
 204
 205         down_read(&crypto_alg_sem);
 206         alg = __crypto_alg_lookup(name, type | test, mask | test);
 207         if (!alg && test) {
 208                 alg = __crypto_alg_lookup(name, type, mask);
 209                 if (alg && !crypto_is_larval(alg)) {
 210                         /* Test failed */
 211                         crypto_mod_put(alg);
 212                         alg = ERR_PTR(-ELIBBAD);
 213                 }
 214         }
 215         up_read(&crypto_alg_sem);
 216
 217         return alg;
 218 }
 219
 220 static struct crypto_alg *crypto_larval_lookup(const char *name, u32 type,
 221                                                u32 mask)
 222 {
 223         struct crypto_alg *alg;
 224
 225         if (!name)
 226                 return ERR_PTR(-ENOENT);
 227
 228         type &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
 229         mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
 230
 231         alg = crypto_alg_lookup(name, type, mask);
 232         if (!alg && !(mask & CRYPTO_NOLOAD)) {
 233                 request_module("crypto-%s", name);
 234
 235                 if (!((type ^ CRYPTO_ALG_NEED_FALLBACK) & mask &
 236                       CRYPTO_ALG_NEED_FALLBACK))
 237                         request_module("crypto-%s-all", name);
 238
 239                 alg = crypto_alg_lookup(name, type, mask);
 240         }
 241
 242         if (!IS_ERR_OR_NULL(alg) && crypto_is_larval(alg))
 243                 alg = crypto_larval_wait(alg);
 244         else if (!alg)
 245                 alg = crypto_larval_add(name, type, mask);
 246
 247         return alg;
 248 }
 249
 250 int crypto_probing_notify(unsigned long val, void *v)
 251 {
 252         int ok;
 253
 254         ok = blocking_notifier_call_chain(&crypto_chain, val, v);
 255         if (ok == NOTIFY_DONE) {
 256                 request_module("cryptomgr");
 257                 ok = blocking_notifier_call_chain(&crypto_chain, val, v);
 258         }
 259
 260         return ok;
 261 }
 262 EXPORT_SYMBOL_GPL(crypto_probing_notify);
 263
 264 struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
 265 {
 266         struct crypto_alg *alg;
 267         struct crypto_alg *larval;
 268         int ok;
 269
 270         /*
 271          * If the internal flag is set for a cipher, require a caller to
 272          * to invoke the cipher with the internal flag to use that cipher.
 273          * Also, if a caller wants to allocate a cipher that may or may
 274          * not be an internal cipher, use type | CRYPTO_ALG_INTERNAL and
 275          * !(mask & CRYPTO_ALG_INTERNAL).
 276          */
 277         if (!((type | mask) & CRYPTO_ALG_INTERNAL))
 278                 mask |= CRYPTO_ALG_INTERNAL;
 279
 280         larval = crypto_larval_lookup(name, type, mask);
 281         if (IS_ERR(larval) || !crypto_is_larval(larval))
 282                 return larval;
 283
 284         ok = crypto_probing_notify(CRYPTO_MSG_ALG_REQUEST, larval);
 285
 286         if (ok == NOTIFY_STOP)
 287                 alg = crypto_larval_wait(larval);
 288         else {
 289                 crypto_mod_put(larval);
 290                 alg = ERR_PTR(-ENOENT);
 291         }
 292         crypto_larval_kill(larval);
 293         return alg;
 294 }
 295 EXPORT_SYMBOL_GPL(crypto_alg_mod_lookup);
 296
 297 static int crypto_init_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
 298 {
 299         const struct crypto_type *type_obj = tfm->__crt_alg->cra_type;
 300
 301         if (type_obj)
 302                 return type_obj->init(tfm, type, mask);
 303
 304         switch (crypto_tfm_alg_type(tfm)) {
 305         case CRYPTO_ALG_TYPE_CIPHER:
 306                 return crypto_init_cipher_ops(tfm);
 307
 308         case CRYPTO_ALG_TYPE_COMPRESS:
 309                 return crypto_init_compress_ops(tfm);
 310
 311         default:
 312                 break;
 313         }
 314
 315         BUG();
 316         return -EINVAL;
 317 }
 318
 319 static void crypto_exit_ops(struct crypto_tfm *tfm)
 320 {
 321         const struct crypto_type *type = tfm->__crt_alg->cra_type;
 322
 323         if (type && tfm->exit)
 324                 tfm->exit(tfm);
 325 }
 326
 327 static unsigned int crypto_ctxsize(struct crypto_alg *alg, u32 type, u32 mask)
 328 {
 329         const struct crypto_type *type_obj = alg->cra_type;
 330         unsigned int len;
 331
 332         len = alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1);
 333         if (type_obj)
 334                 return len + type_obj->ctxsize(alg, type, mask);
 335
 336         switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
 337         default:
 338                 BUG();
 339
 340         case CRYPTO_ALG_TYPE_CIPHER:
 341                 len += crypto_cipher_ctxsize(alg);
 342                 break;
 343
 344         case CRYPTO_ALG_TYPE_COMPRESS:
 345                 len += crypto_compress_ctxsize(alg);
 346                 break;
 347         }
 348
 349         return len;
 350 }
 351
 352 static void crypto_shoot_alg(struct crypto_alg *alg)
 353 {
 354         down_write(&crypto_alg_sem);
 355         alg->cra_flags |= CRYPTO_ALG_DYING;
 356         up_write(&crypto_alg_sem);
 357 }
 358
 359 struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 type,
 360                                       u32 mask)
 361 {
 362         struct crypto_tfm *tfm = NULL;
 363         unsigned int tfm_size;
 364         int err = -ENOMEM;
 365
 366         tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, type, mask);
 367         tfm = kzalloc(tfm_size, GFP_KERNEL);
 368         if (tfm == NULL)
 369                 goto out_err;
 370
 371         tfm->__crt_alg = alg;
 372
 373         err = crypto_init_ops(tfm, type, mask);
 374         if (err)
 375                 goto out_free_tfm;
 376
 377         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 378                 goto cra_init_failed;
 379
 380         goto out;
 381
 382 cra_init_failed:
 383         crypto_exit_ops(tfm);
 384 out_free_tfm:
 385         if (err == -EAGAIN)
 386                 crypto_shoot_alg(alg);
 387         kfree(tfm);
 388 out_err:
 389         tfm = ERR_PTR(err);
 390 out:
 391         return tfm;
 392 }
 393 EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
 394
 395 /*
 396  *      crypto_alloc_base - Locate algorithm and allocate transform
 397  *      @alg_name: Name of algorithm
 398  *      @type: Type of algorithm
 399  *      @mask: Mask for type comparison
 400  *
 401  *      This function should not be used by new algorithm types.
 402  *      Please use crypto_alloc_tfm instead.
 403  *
 404  *      crypto_alloc_base() will first attempt to locate an already loaded
 405  *      algorithm.  If that fails and the kernel supports dynamically loadable
 406  *      modules, it will then attempt to load a module of the same name or
 407  *      alias.  If that fails it will send a query to any loaded crypto manager
 408  *      to construct an algorithm on the fly.  A refcount is grabbed on the
 409  *      algorithm which is then associated with the new transform.
 410  *
 411  *      The returned transform is of a non-determinate type.  Most people
 412  *      should use one of the more specific allocation functions such as
 413  *      crypto_alloc_blkcipher.
 414  *
 415  *      In case of error the return value is an error pointer.
 416  */
 417 struct crypto_tfm *crypto_alloc_base(const char *alg_name, u32 type, u32 mask)
 418 {
 419         struct crypto_tfm *tfm;
 420         int err;
 421
 422         for (;;) {
 423                 struct crypto_alg *alg;
 424
 425                 alg = crypto_alg_mod_lookup(alg_name, type, mask);
 426                 if (IS_ERR(alg)) {
 427                         err = PTR_ERR(alg);
 428                         goto err;
 429                 }
 430
 431                 tfm = __crypto_alloc_tfm(alg, type, mask);
 432                 if (!IS_ERR(tfm))
 433                         return tfm;
 434
 435                 crypto_mod_put(alg);
 436                 err = PTR_ERR(tfm);
 437
 438 err:
 439                 if (err != -EAGAIN)
 440                         break;
 441                 if (fatal_signal_pending(current)) {
 442                         err = -EINTR;
 443                         break;
 444                 }
 445         }
 446
 447         return ERR_PTR(err);
 448 }
 449 EXPORT_SYMBOL_GPL(crypto_alloc_base);
 450
 451 void *crypto_create_tfm(struct crypto_alg *alg,
 452                         const struct crypto_type *frontend)
 453 {
 454         char *mem;
 455         struct crypto_tfm *tfm = NULL;
 456         unsigned int tfmsize;
 457         unsigned int total;
 458         int err = -ENOMEM;
 459
 460         tfmsize = frontend->tfmsize;
 461         total = tfmsize + sizeof(*tfm) + frontend->extsize(alg);
 462
 463         mem = kzalloc(total, GFP_KERNEL);
 464         if (mem == NULL)
 465                 goto out_err;
 466
 467         tfm = (struct crypto_tfm *)(mem + tfmsize);
 468         tfm->__crt_alg = alg;
 469
 470         err = frontend->init_tfm(tfm);
 471         if (err)
 472                 goto out_free_tfm;
 473
 474         if (!tfm->exit && alg->cra_init && (err = alg->cra_init(tfm)))
 475                 goto cra_init_failed;
 476
 477         goto out;
 478
 479 cra_init_failed:
 480         crypto_exit_ops(tfm);
 481 out_free_tfm:
 482         if (err == -EAGAIN)
 483                 crypto_shoot_alg(alg);
 484         kfree(mem);
 485 out_err:
 486         mem = ERR_PTR(err);
 487 out:
 488         return mem;
 489 }
 490 EXPORT_SYMBOL_GPL(crypto_create_tfm);
 491
 492 struct crypto_alg *crypto_find_alg(const char *alg_name,
 493                                    const struct crypto_type *frontend,
 494                                    u32 type, u32 mask)
 495 {
 496         if (frontend) {
 497                 type &= frontend->maskclear;
 498                 mask &= frontend->maskclear;
 499                 type |= frontend->type;
 500                 mask |= frontend->maskset;
 501         }
 502
 503         return crypto_alg_mod_lookup(alg_name, type, mask);
 504 }
 505 EXPORT_SYMBOL_GPL(crypto_find_alg);
 506
 507 /*
 508  *      crypto_alloc_tfm - Locate algorithm and allocate transform
 509  *      @alg_name: Name of algorithm
 510  *      @frontend: Frontend algorithm type
 511  *      @type: Type of algorithm
 512  *      @mask: Mask for type comparison
 513  *
 514  *      crypto_alloc_tfm() will first attempt to locate an already loaded
 515  *      algorithm.  If that fails and the kernel supports dynamically loadable
 516  *      modules, it will then attempt to load a module of the same name or
 517  *      alias.  If that fails it will send a query to any loaded crypto manager
 518  *      to construct an algorithm on the fly.  A refcount is grabbed on the
 519  *      algorithm which is then associated with the new transform.
 520  *
 521  *      The returned transform is of a non-determinate type.  Most people
 522  *      should use one of the more specific allocation functions such as
 523  *      crypto_alloc_blkcipher.
 524  *
 525  *      In case of error the return value is an error pointer.
 526  */
 527 void *crypto_alloc_tfm(const char *alg_name,
 528                        const struct crypto_type *frontend, u32 type, u32 mask)
 529 {
 530         void *tfm;
 531         int err;
 532
 533         for (;;) {
 534                 struct crypto_alg *alg;
 535
 536                 alg = crypto_find_alg(alg_name, frontend, type, mask);
 537                 if (IS_ERR(alg)) {
 538                         err = PTR_ERR(alg);
 539                         goto err;
 540                 }
 541
 542                 tfm = crypto_create_tfm(alg, frontend);
 543                 if (!IS_ERR(tfm))
 544                         return tfm;
 545
 546                 crypto_mod_put(alg);
 547                 err = PTR_ERR(tfm);
 548
 549 err:
 550                 if (err != -EAGAIN)
 551                         break;
 552                 if (fatal_signal_pending(current)) {
 553                         err = -EINTR;
 554                         break;
 555                 }
 556         }
 557
 558         return ERR_PTR(err);
 559 }
 560 EXPORT_SYMBOL_GPL(crypto_alloc_tfm);
 561
 562 /*
 563  *      crypto_destroy_tfm - Free crypto transform
 564  *      @mem: Start of tfm slab
 565  *      @tfm: Transform to free
 566  *
 567  *      This function frees up the transform and any associated resources,
 568  *      then drops the refcount on the associated algorithm.
 569  */
 570 void crypto_destroy_tfm(void *mem, struct crypto_tfm *tfm)
 571 {
 572         struct crypto_alg *alg;
 573
 574         if (unlikely(!mem))
 575                 return;
 576
 577         alg = tfm->__crt_alg;
 578
 579         if (!tfm->exit && alg->cra_exit)
 580                 alg->cra_exit(tfm);
 581         crypto_exit_ops(tfm);
 582         crypto_mod_put(alg);
 583         kzfree(mem);
 584 }
 585 EXPORT_SYMBOL_GPL(crypto_destroy_tfm);
 586
 587 int crypto_has_alg(const char *name, u32 type, u32 mask)
 588 {
 589         int ret = 0;
 590         struct crypto_alg *alg = crypto_alg_mod_lookup(name, type, mask);
 591
 592         if (!IS_ERR(alg)) {
 593                 crypto_mod_put(alg);
 594                 ret = 1;
 595         }
 596
 597         return ret;
 598 }
 599 EXPORT_SYMBOL_GPL(crypto_has_alg);
 600
 601 void crypto_req_done(struct crypto_async_request *req, int err)
 602 {
 603         struct crypto_wait *wait = req->data;
 604
 605         if (err == -EINPROGRESS)
 606                 return;
 607
 608         wait->err = err;
 609         complete(&wait->completion);
 610 }
 611 EXPORT_SYMBOL_GPL(crypto_req_done);
 612
 613 MODULE_DESCRIPTION("Cryptographic core API");
 614 MODULE_LICENSE("GPL");